SFP 25 1920
989
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ANTIAIRCRAFT MATÉRIEL
• - FOR
MACHINE GUNS
SERVICE HANDBOOK
Prepared in the
Office of the Chief of Ordnance
November, 1919
WASHINGTON
GOVERNMENT PRINTING OFFICE
1920


WAR DEPARTMENT.
Document No. 989.
Office of The Adjutant General.
\\\
5 ).3
AºS
\4)4
FRONTIS PIECE.
PLATE 1.
Handley-Page Bombing Plane encircling
Washington Monument.
Browning Machine Gun on Antiaircraft
Mount.


WAR DEPARTMENT,
WASHINGTON, November 25, 1919.
The following publication, entitled “Antiaircraft Matériel for
Machine Guns, Service Handbook,” is published for the information
and guidance of all concerned.
[062.1, A. G. O.]
BY ORDER OF THE SECRETARY OF WAR :
PEYTON C. MARCH,
General, Chief of Staff.
OFFICIAL:
P. C. HARRIS,
The Adjutant General.
INTRODUCTION.
The object of this book is to describe and explain the use of anti-
aircraft machine gun matériel.
Machine guns of the ordinary mobile army type are used without
alteration for antiaircraft purposes. The antiaircraft devices and
attachments used with these guns are attached to or receive the guns
as issued for field service.
The following handbooks, or those Superseding them, descriptive
of the various guns and a trailer, should be used in connection with
this book, as no attempt has been made to cover the subjects treated
in those publications:
No. 1937, Browning Machine Gun, Model of 1917. A revised version of this
handbook is to be issued as War College Series No. 22.
No. 1775, Wickers Machine Gun, Model of 1915.
No. 1933, Marlin Aircraft Machine Gun, Model of 1917.
No. 1932, Hotchkiss Machine Gun, Model of 1914.
No. 1931, Lewis Machine Gun, Model of 1917.
No. 845, War Department Document. Browning Automatic Rifle, Model 'of
1918.
No. 1980, Antiaircraft Machine Gun Trailer, Model 1918.
lº-Present status of matériel referred to in this handbook is as follows (May 1,
) :
Vickers Machine Gun, Caliber .30, Model of 1915 (2).
Hotchkiss Machine Gun, Čaiſbér, 8-mm. Modeſ of iſ 14 (2).
Lewis Machine Gun, Caliber .30, Model of 1917 ſº type) (4).
Browning Machine Gun, Caliber .30, Model of 1917 (5).
Browning Automatic Rifle, Caliber .30, Model of 1918 (5).
Marlin Tank Machine Gun, Caliber .30, Model of 1918 (3).
Mariin Aircraft Machine Gun, Model of 1917 (7 mg.), Câjîber .30 (2).
Antiaircraft 8ights, adapters, and shoulder Stocks for each gun are similarly classified,
#} Matériel obsolete for issue to troops or for further manufacture.
2) Matériel issued to troops for active use, but considered obsolete for future manu-
facture except for maintenance or emergency production. *
(3) Matériel issued to troops which will probably be replaced by matériel classified
under “A” or “B,” but which is considered suitable as a reserve for active use in the case
of war. Obsolete for future manufacture.
(4) Matériel issued to troops for training or other special purposes, but which is not
considered Suitable for active use in modern warfare. Obsolete for future manufacture.
f º Matériel issued to troops for active use, and considered standard for future manu-
a Cºtt] re.
4
TABLE OF CONTENTS.
Iſist of illustration plates
Conversion tables, weights, measures
Terms used in describing aircraft
CHAPTER I. GENERAL CONSIDERATIONS:
Antiaircraft machine guns
Limitations of aircraft in defense work
Limits of use of antiaircraft machine guns
Searchlights
Wireless intercepting stations
Liaison between antiaircraft and air Service
Use of Small arms against aircraft
Use of firing time
Visibility—distinguishing friend from foe
Clouds
Ammunition, armor-piercing, tracer, and incendiary
Training in antiaircraft fire
• Sighting guide for Small arms without antiaircraft sights___________
CHAPTER II. ANTIAIRCRAFT MACHINE-GUN SIGHTS :
Introduction
Trend of design
Use of the two types of Sight
The main factors in antiaircraft fire
Practical sight design and sighting factors
CHAPTER III. TRENCH SIGHT, ANTIAIRCRAFT (Front Area Sight):
Theory
General description º
General directions for use
Correct and incorrect aiming with Trench Sight (Front Area Sight)_
Directions for attaching and use and list of parts of sight for :
Browning Automatic Rifle, Model of 1918
Browning Machine Gun, Model of 1917
Vickers Machine Gun, Model of 1915
Lewis Machine Gun, Model of 1917
Marlin Aircraft Machine Gun, Model of 1917
Marlin Tank Machine Gun, Model of 1918
Hotchkiss Machine Gun, Model of 1914
CHAPTER IV. PEYCRU SIGHT, ANTIAIRCRAFT (Rear Area Sight):
Theory
General description
General directions for use
Directions for attaching and use and list of parts of sight for :
Hotchkiss Machine Gun, Model of 1914
Browning Machine Gun, Model of 1917
Vickers Machine Gun, Model 1915
Marlin Tank Machine Gun, Model of 1918
Marlin Aircraft Machine Gun, Model of 1917----
1Page.
11
13
17
19
19
19
19
19
19
21
23
23
25
25
26
28
6 TABLE OF CONTENTS.
CHAPTER W. THE STADIA : Page.
Description-- 71.
Theory of use 73
DirectionS for use *-º 73
CHAPTER VI. ANTIAIRCRAFT MACHINE-GUN MOUNTS :
General introduction 77
Types 77
Trend of design 78
Antiaircraft Adapter for Machine Gun Tripod, Model of 1917 (Brown-
ing), and Machine Gun Tripod, Model of 1918 (Cygnet). Descrip-
tion ; directions for attaching ; nethod of use; parts------________ '78
Antiaircraft Improvised Post Mount. Description ; directions for set-
ting up and use; list of parts 86
Antiaircraft Machine Gun Tripod, Model of 1918. Description ; di-
rections for setting up and use; list of parts 93
Antiaircraft Machine Gun Mount, Cygnet type, mounted on Cygnet
Trailer with Ammunition Trailer. Description ; directions for set-
ting up and use; directions for assembling; list Of parts---------- 101
Antiaircraft Machine Gun Trailer, Model 1918 (Sechler) --__________ 119
Adapters for machine guns used on antiaircraft mounts. Browning
and Vickers Adapter; Marlin Aircraft and Marlin Tank Adapter;
Lewis Adapter; Hotchkiss Adapter; Browning Automatic Riſle
Adapter ––––– - * * * e 123
Antiaircraft Machine Gun Light Folding Stand (British) --_________ 134
CHAPTER VII. SHOULDER STOCKS :
Introduction 137
Description ; directions for attaching and use; list of parts of
Stocks for :
Browning Machine Gun, Model of 1917-------- 137
Vickers Machine Gun, Model of 1915__ 139
Marlin Aircraft Machine Gun, Model of 1917, and Marlin Tank
Machine Gun, Model of 1918 141
Hotchkiss Machine Gun, Model of 1914 - - j42
CHAPTER VIII. ACCESSORIES :
Cartridge belts. Browning, Colt (Marlin), Wickers, Expendable_____ 145
Belt-loading machines. Browning, Marlin-Colt, Wickers____________ 147
Ammunition boxes. Browning, Vickers, Expendable 149
Water boxes. Browning, Vickers--------------------------------- 156
Cartridge belt guide. Description and list of parts 159–160
Stadia (range indicator) s 160
Eyeglasses with Fieuzal lens - *m tº 163
40-round Magazine for Browning Automatic Rifle. Description and
list of parts----------- 163–165
PLATE
PLATE
PLATE
PLATE
PLATE
PLATE
PLATE
PLATE
PLATE
PLATE
PLATE
LIST OF ILLUSTRATION PLATES.
CHAPTER I. GENERAL CONSIDERATIONS.
1. Frontispiece. Handley-Page bombing plane encircling Wash-
ington Monument, with Browning machine gun trained on
Same from antiaircraft mount
2. Using an antiaircraft machine gun in trench at the front,
American Expeditionary Forces using Hotchkiss gun------
3. Cover for antiaircraft machine guns. American EXpedition-
ary Forces, France, using a Hotchkiss gun mounted on a
grape arbor sº
4. Cover for antiaircraft machine guns. American Expedition-
ary Forces, France, using Hotchkiss gun reversed on its
tripod against enemy aircraft
5. Antiaircraft machine-gun cartridges, .30 caliber--------------
CHAPTER III. TRENCH SIGHTS, ANTIAIRCRAFT (Front Area).
6. Trench sight Antiaircraft (Front Area Sight). Showing front
sight and rear sight as made for Marlin Tank Machine Gun,
front sight upright
7. Trench Sight, Antiaircraft (Front Area Sight), as made for
Marlin Tank Machine Gun ; showing front sight (a) par-
tially, and (b) completely, down
. Diagram of theory of use of antiaircraft sights______________
9. Diagrams of theory of use of antiaircraft sightS______________
10. Diagram showing correct and incorrect aim at aircraft with the
Trench Sight (Front Area Sight)
11. Trench Sight, Antiaircraft (Front Area Sight), for Browning
Automatic Rifle, Model of 1918
8
PLATE 12. Trench Sight, Antiaircraft (Front Area Sight), for Browning
Machine Gun, Model of 1917 * *
PLATE 13. Trench Sight, Antiaircraft (Front Area Sight), for Vickers
•ºss Machine Gun, Model of 1915
PLATE 14. Trench Sight, Antiaircraft (Front Area Sight), for Lewis
Machine Gun, Model of 1917 •
PLATE 15. Trench Sight, Antiaircraft (Front Area Sight), for Marlin
Aircraft Machine Gun, Model of 1917 * *
PLATE 16. Trench Sight, Antiaircraft (Front Area Sight), for Marlin
Tank Machine Gun, Model of 1918
PLATE 17. Trench Sight, Antiaircraft (Front Area Sight), for Hotchkiss
Machine Gun, Model of 1914
CHAPTER IV. PEYCRU SIGHT, ANTIAIRCRAFT (Rear Area).
PLATE 18. Peycru Sight, Antiaircraft (Rear Area Sight). Shown as
mounted on Browning, Mchine Gun, with line of sight from
gunner's eye to aircraft. Enlargement of front sight frame
and rear sight beaded bar included in plate
PLATE 19. Diagram illustrating windage allowance instructions for Pey-
cru Sight (Rear Area Sight)
Page.
2
16
18
30
31
32.
33
36
3S
40
42
44
46
48
52
54
PLATE 20.
PLATE 21.
PLATE 22.
PLATE 23.
PLATE 24.
PLATE 25.
PLATE 26.
PLATE 27.
PLATE 28.
PLATE 29.
PLATE
PLATE
PLATE
PLATE
PLATE
PLATE
PLATE
PLATE
PLATE
PLATE
PLATE
PLATE
PLATE
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
LIST OF ILLUSTRATION PLATES.
Peycru Sight, Antiaircraft (Rear Area Sight), for Hotchkiss
Machine Gun, Model of 1914
Peycru Sight, Antiaircraft (Rear Area Sight), for Browning
Machine Gun, Model of 1917
Peycru Sight, Antiaircraft (Rear Area Sight), for Vickers Ma-
chine Gun, Model of 1915
Peycru Sight, Antiaircraft (Rear Area Sight), for Marlin Tank
Machine Gun, Model of 1918
Peycru Sight, Antiaircraft (Rear Area Sight), for Marlin Air-
Craft Machine Gun, Model of 1917 - -
CHAPTER V. STADIA (RANGE INDICATOR).
The Stadia, Peycru; (a) complete; (b) half section views
'showing how aircraft should appear in Stadia
Diagram illustrating theory of the stadia
An Officer using the stadia range indicator
CHAPTER VI. ANTIAIRCRAFT MACHINE GUN MoUNTs.
Antiaircraft machine gun mount improvised by American Ex-
peditionary Forces, Belgium. Shows Lewis Machine Gun
with clamp section of British Light Folding Stand mounted
On a Spike in top Of post
Antiaircraft Adapter for Machine Gun Tripod, Model of 1917
(Browning), and Machine Gun Tripod, Model of 1918 (Cyg-
net), complete
Antiaircraft adapter for machine-gun tripods mounted on
Machine Gun Tripod, Model of 1917 (Browning) -----------
Antiaircraft adapter for machine-gun tripods as used in field
on Machine Gun Tripod, Model of 1917 (Browning), with
Browning Machine Gun with antiaircraft equipment________
Antiaircraft adapter for machine-gun tripods mounted On Ma-
chine Gun Tripod, Model of 1918 (Cygnet)
Antiaircraft adapter for machine-gun tripods as used in field
on Machine Gun Tripod, Model of 1918 (Cygnet), with
Browning Machine Gun with antiaircraft equipment_______
Improvised Post Mount, Antiaircraft. Assembled view_______
Improvised Post Mount, Antiaircraft. Dismounted view______
Improvised Post Mount, Antiaircraft, as used with Browning
Machine Gun, Model of 1917, and Lewis Machine Gun, Model
of 1917, with antiaircraft equipment
Improvised Post Mount, Antiaircraft, as used with Browning
Automatic Rifle, Model Of 1918, with 40-round Magazine_-__
Improvised Post Mount, Antiaircraft, as used with Vickers
Machine Gun, Model of 1915, with antiaircraft equipment___
Improvised Post Mount, Antiaircraft, as used with Hotchkiss
Machine Gun, Model of 1914, with antiaircraft equipment__
Antiaircraft Machine Gun Tripod, Model of 1918— -----------
Antiaircraft Machine Gun Tripod, Model of 1918, as used with
Browning Machine Gun, Modèl of 1917, with antiaircraft
equipment -
Antiaircraft Machine Gun Tripod, Model of 1918, as used with
Vickers Machine Gun, Model of 1915, with antiaircraft
equipment
Page.
61
63
65
67
69
72
73
74
76
79
81
82
84
87
88
89
90
91
92
94
95
PLATE 43.
PLATE 44.
PLATE 45.
PLATE 46.
PLATE 47.
PLATE 48.
PLATE 49.
PLATE 50.
PLATE 51.
PLATE 52.
PLATE 53.
PLATE 54.
PLATE 55.
PLATE 56.
PLATE 57.
PLATE 58.
PLATE 59.
PLATE 60.
PLATE 61.
LIST OI!' ILLUSTRATION PLATES.
Antiaircraft Machine Gun Tripod, Model of 1918, as used with
Marlin Tank Machine Gun, Model of 1918, with antiaircraft
equipment -
Antiaircraft Machine Gun Tripod, Model of 1918, as used with
Lewis Machine Gun, Model of 1917, with antiaircraft equip-
ment
Antiaircraft Machine Gun Tripod, Model of 1918, as used with
Hotchkiss Machine Gun, Model of 1914; with antiaircraft
equipment
Antiaircraft Machine Gun Mount, Cygnet type, on Cygnet
Trailer, as used with Browning Machine Gun, Model of 1917,
with antiaircraft equipment
Antiaircraft Machine Gun Mount, Cygnet type, on Cygnet
Trailer, as used with Lewis Machine Gun, Model of 1917,
with antiaircraft equipment
Antiaircraft Machine Gun Mount, Cygnet type, on Cygnet
Trailer, as used with Vickers Machine Gun, Model of 1915,
with antiaircraft equipment
Antiaircraft Machine Gun Mount, Cygnet type, on Cygnet
Trailer, as used with Marlin Tank Machine Gun, Model of
1918, with antiaircraft equipment
Antiaircraft Machine Gun Mount, Cygnet type, on Cygnet
Trailer, as used with Hotchkiss Machine Gun, Model of 1914,
With antiaircraft equipment
Antiaircraft Machine Gun Mount, Cygnet type, on Cygnet
Trailer. Mount Trailer only
Antiaircraft Machine Gun Mount, Cygnet type, on Cygnet
Trailer. Ammunition Trailer only
Antiaircraft Machine Gun Trailer, Model 1918, Sechler type,
with Cygnet Mount and Antiaircraft Machine Gun Tripod,
Model of 1918. Complete view, right side
Antiaircraft Machine Gun Trailer, Model 1918, Sechler type,
with Cygnet Mount, and Antiaircraft Machine Gun Tripod,
Model of 1918, with Marlin Tank and Browning Machine
Guns, with antiaircraft equipment. Body view, left side___
Adapter, Browning and Vickers, for using Browning Machine
Gun, Model of 1917, or Vickers Machine Gun, Model of 1915,
On antiaircraft mounts -
Adapter, Browning and Vickers, for using Browning Machine
Gun, Model of 1917, or Vickers Machine Gun, Model of 1915,
On antiaircraft mounts. Complete with Vickers Ammuni-
tion Box Container, or basket, as issued for Vickers gun---
Adapter, Marlin, for using Marlin Aircraft Machine Gun, Model
of 1917, or Marlin Tank Machine Gun, Model of 1918, on
antiaircraft mounts_ -
Adapter, Lewis, for using Lewis Machine Gun, Model of 1917,
On antiaircraft mounts - - -
Adapter, Eſotchkiss, for using Hotchkiss Machine Gun, Model
of 1914, on antiaircraft mounts - -
Adapter, Browning Automatic Rifle, for using Browning Auto-
matic Rifle, Model of 1918, On antiaircraft mounts__________
Antiaircraft Machine Gun Light Folding Stand, British, as
used with Lewis Machine Gun, with Trench Sight__________
Page.
97
98
99
102
103
104
105
106
108
110
121
124
128
131
132
10
PLATE
PLATE
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| PLATE
PLATE
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PLATE
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
LIST OF ILLUSTRATION PLATES.
CHAPTER VII. ANTIAIRCRAFT MACHINE GUN STOCKS,
Shoulder Stock for Browning Machine Gun, Model of 1917--__
Shoulder Stock for Vickers Machine Gun, Model of 1915
Shoulder Stock for Marlin Tank Machine Gun, Model of 1918,
and Marlin Aircraft Machine Gun, Model of 1917
* - - - - - - ºr * * *
Shoulder Stock for Hotchkiss Machine Gun, Model of 1914____
CHAPTER VIII. ACCESSORIES.
Sections, showing leading ends, of Browning Cartridge Belt,
used with Browning Machine Gun ; Colt Cartridge Belt, used
with Marlin Machine Guns; and Vickers Cartridge Belt, used
With Vickers Machine Gun
Sections of disintegrating belts of metallic links, used by U. S.
aircraft
Browning Belt Loading Machine
Vickers Belt Iloading Machine, loading Vickers Cartridge Belt.
(Cartridges shown are old style, round nosed)
Ammunition Box, Browning, standard wooden type
Ammunition BOX, Wickers__
Ammunition Box, Expendable, Mark I
Ammunition Box, Expendable, Mark I, attached to head of
machine-gun tripod; showing cover stripped back prepara-
tory to use of cartridge belt
Water Box, Vickers, with filling cup (funnel)
Water Box, Browning
Cartridge Belt Guide---------------------------------------
Cartridge Belt Guide as used on Browning Ammunition Box;
showing leading end of Browning Cartridge Belt
Cartridge Belt Guide as used on Wickers Ammunition Box;
showing leading end of Vickers Cartridge Belt
Eyeglasses, or goggles, for antiaircraft work; illustrating a
desirable type
Forty-round Magazine for Browning Automatic Rifle.
in place in a section of the
rifle
ShOWn
Forty-round Magazine for Browning Automatic Rifle. Parts__
Page.
136
139
140
143
144
146
14S
150
152
152
154
164
165
•
i
::i
CONVERSION TABLES.
Weights, Measures, and Thermometers.
Weight
metric ton---------------------------------------.2,204.6 pounds (avoir.).
kilogram———— *— — — — — — — — — — — — — — - - - - - - - - - - - - - 2.2046 pounds (avoir.).
8Tºlſh--------------------------------------------- 0.03527 ounce (avoir.).
ton---------------------------------------------- 1,016 kilograms.
pound-------------------------------------------0.4536 kilogram.
Ollnce-------------------------------------------- 28.35 grams.
Linear measure.
kilometer---------------------------------------- 0.6214 mile.
meter--------------------------------------------39.39 inches.
centimeter---------------------------------------0.3937 inch.
millimeter----------------------------------------0.03937 inch.
mile ----------------------------------------- 1.609 kilometers.
yard--------------------------------------------- 0.9144 meter.
foot - - - -ºm sma. * * * - - - - - - - - * * * * * - - - - - - - - emm * *- - - - -0.3048 meter.
inch----- — — — — — — — — — — — — — — — — — — — — — — — — — — — - - - - - - - - - - - - - 2.54 centimeters.
Square measure. -
Square kilometer---------------------------------.0.3861 square mile.
Square meter__ -10.76 square feet.
Square Centimeter-------------- - - - 0.1550 Square inch.
Square mile - 2.590 Square kilometers.
square foot - - 0.0929 square meter.
Square inch--- t 6.452 Square centimeters.
Cubic measure
cubic meter-------------------------------------- 85.314 cubic feet.
cubic centimeter---------------------------------. 0.0610 Cubic inch.
cubic foot----------------------------------------0.02832 cubic meter.
cubic inch---------------------------------------. 16.3S7 cubic centimeters.
- Capacity.
gallon----- - - - - - - - - - - - -m. am em sm - - -3,785 liters.
Cubic foot - —v 28.317 liters.
liter——— - - 61,023 cubic inches.
liter--------- 2.20 pounds water.
Miscellaneous
pound (avoir.) ------------ - __7,000 grains.
metric ton––––––––––––––––– ––––1,000 kilograms.
gallon 231 cubic inches.
British imperial gallon--------------------------- 277.418 cubic inches.
gallon gasoline weighs 6.50 pounds.
Cubic foot of Water Weighs----------------------- 62.287 pounds at 62° F.
gallon of water weighs________ S.3267 pounds at 62° F.
knot 1.15 miles.
T1
12 CONVERSION TABLES.
COMPARATIVE SCALES OF THERMOMETERS.

Reaumur | Centigrade Fahrenheit
(R.). (C (Fahr.). Remarks.
o o o
80.0 100.0 212 | Water boils at sea level.
68.0 85. 0 185
60. 0 75. 0 167 || Alcohol boils.
48. 0 60. 0 140
42.2 52.8 127 | Tallow melts.
36.0 45. 0 113
29.3 36.7 98 || Blood heat.
24.0 30. 0 86
12.4 15.3 60 | Temperate.
8. 0 10. 0 50
4.0 5. 0 41
0.0 0.0 32 || Water freezes (zero Centigrade
and Reaumur).
— 8.0 —10. 0 14
—14.2 —17.8 0 | Zero Fahrenheit.
—16.0 —20.0 — 4
—24.0 —30. 0 –22
–32.0 —40.0 —40
The Fahrenheit thermometer is in general use in the United States and
English-speaking countries. 180° from freezing to boiling.
The Centigrade thermometer is mainly used in France and other countries
having the metric system. It is used for scientific purposes in every country.
100° from freezing to boiling points.
The Reaumur thermometer is used mainly in Germany and Russia. 80° from
freezing to boiling pointS.
TO COnvert— *
Fahrenheit to Centigrade; subtract 32 and multiply by 5/9.
Fahrenheit to Reaumur; subtract 32 and multiply by 4/9.
Centigrade to Fahrenheit; multiply by 9/5 and add 32.
Centigrade to Reaumur ; multiply by 4/5.
Reaumur to Fahrenheit; multiply by 9/4 and add 32.
Reaumur to Centigrade; multiply by 5/4.
TERMS USED IN DESCRIBING AIRCRAFT.
Airplane :
An aircraft heavier than air.
Monoplane: 2 -
An airplane with one wing on each side of the body.
Biplane:
An airplane with two wings on each side of the body.
Triplane:
An airplane with three wings on each side of the body.
TractOr machines:
Airplanes having the airSCrew, Or propeller, in front Of the WingS.
Pusher machines:
Airplanes having the airscrew, or propeller, behind the Wings.
Nacelle :
The body of a pusher machine which carries the engine controls, observer,
and pilot. In these machines the nacelle projects well in front of the
WingS. g
Fuselage:
The body of a tractor airplane, which carries the pilot, observer, and
engine, and extends back as far as the tail. All fuselages now are COV-
ered with canvas or 3-ply wood.
Under carriage:
The part of the structure connecting the wheels to the nacelle or fuselage.
Tail :
The small horizontal plane at the end of the fuselage.
Rudder :
The Small vertical movable plane or planes attached to the tail.
Fin : -
A small vertical fixed plane on the top of the fuselage and tail. The rud-
der is usually attached to the rear end of the fin.
Stagger:
An airplane is said to have stagger when the lower wings are not set ver-
tically below the upper wings when the airplane is in the flying position.
Dihedral :
An airplane is said to have dihedral when the wings, as seen from the
front, are set at an angle to each other on either side of the body.
Leading edge:
The front edge of the wings of an airplane.
Trailing edge:
The rear edge of the wings of an airplane.
Ailerons:
The flaps fitted to the trailing edge of the main plane in order to give
lateral control. Ailerons are sometimes very conspicuous.
Overhang or extensions:
An airplane is said to have Overhang when the upper wings are longer
than the lower wings.
13
14 TERMS USED IN DESCRIBING AIRCRAFT.
Sweep back: º
An airplane is said to be swept back when the wings, as seen from above
Or below, are not set in a straight line. Sometimes the leading edge is
swept back whilst the trailing edge is straight.
Cut back :
When the trailing edge is longer than the leading edge.
Wedge shape: *
When the leading edge is longer than the trailing edge.
Struts :
The Supports joining the upper wings to the lower wings.
Spread:
Width of an airplane from wing tip to wing tip.
Chord : . -
Distance from the leading edge to the trailing edge of a wing.
Aspect ratio :
Ratio of spread to chord. A plane has a high aspect ratio when the
wings appear long and narrow. - -
Gap :
Vertical distance between the leading edges of the upper and lower main
planes.
Elevators :
The movable portion of the horizontal tailplane for controlling the ascent
or descent of the airplane.
Balloon :
An aircraft lighter than air.
Observation balloon:
A captive balloon used for Observation purposes.
Dirigible balloon or airship :
A motor driven, elongated balloon of rigid or nonrigid type. The first
type is stiffened by framework, the second only by the gas filling.
Bridle : .
The System of ropes attaching a Cable to a captive balloon.
Envelope, Or gas bag : -
The balloon proper, the bag which holds the gas.
Basket: . .
The car suspended beneath a balloon.
Net, or Suspension :
. The system of ropes or rigging which supports the basket or car.
Lobes: * . - t . . .
Air bags at the stern of an elongated balloon.
Equator: -
The greatest horizontal circumference of a spherical balloon.
Stream line : - .
The slope of a balloon whose diameter diminishes toward front and rear.
152535–20–2
15
PLATE 2.
USING AN ANTIAIRCRAFT MACHINE GUN AT THE FRONT. (GUN SHOWN IS A
HOTCHKISS, WITH INFANTRY CORRECTOR SIGHT, NOW DISCARDED.)
16

CHAPTER I.
GENERAL CONSIDERATIONS.
1. - ANTIAIRCRAFT MACHINE GUNS.
The antiaircraft machine gun does not in itself differ in any way
from the ordinary service machine gun. It is, however, equipped
with several accessories adapting it for high-angle fire.
It is necessary that the gun be mounted in such a manner that the
gunner can easily follow a quickly moving, flying target, and in
nearly all of the mounts the gun support swings freely in a horizon-
tal plane about some fixed point, and can be elevated from approxi-
mately 15° depression to 90° elevation. There is no means provided
on antiaircraft mounts for laying the gun accurately in fixed posi-
tion, the idea being to follow the target by direct pointing.
Antiaircraft machine guns are also provided with auxiliary
stocks to facilitate steadying the gun while firing. These stocks.
attach easily at some convenient point on each gun.
Adapters are used which permit various types of guns to be used
on the same mount.
Wheeled mounts, known as trailers, are provided for facilitating
the transportation of machine guns by certain corps.
Guns employed in the defense of forward areas are equipped
with a fixed sight, rapidly usable because it requires no adjusting,
which is known as the Trench Sight. The Trench, or front area,
sights for the various guns are similar, differing only in the means
of attachment to the gun. Guns used in defending rear areas are
equipped with the Peycru Sight, which is adjustable. The reason
for this difference in sights used is that attacking airplanes fly low
over the forward fighting area in order to use their guns on the men
in the trenches and battle front generally, within easy range, but
traveling rapidly, while the heavy, slower bombing aircraft which
attack the rear area fly high to escape artillery, and make the use of
an adjustable sight advisable.
A range indicator, known as a Stadia, is used to estimate the range
of aircraft.
Eyeglasses, or goggles, with Fieuzal lens (amber with a tinge of
green), are also employed in antiaircraft work and constitute part
of the equipment.
Antiaircraft machine-gun mounts, adapters, stocks, trailers,
sights, stadia, and eyeglasses are described in detail in the following
pageS. -
17
PLATE 3.
---
---
-º-
COVER FOR ANTIAIRCRAFT MACHINE GUNS, USING A HOTCH KISS GUN
MOUNTED ON A GRAPE ARBOR.

18
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 19
2. LIMITATIONS OF AIRCRAFT IN DEFENSE WORK.
The work of aircraft, because of the large number of machines that
Would be required to maintain full control of the air, is essentially
confined to offensive fighting and observation. It is very difficult for
a pilot to see enemy machines below him or at any great distance
away—although they may be plainly visible from the ground.
Fighting at a low altitude is also impracticable for aircraft, because
of the limited space for maneuvering. Therefore, enemy aircraft
must be, to a great extent, engaged from the ground.
3. LIMITS OF USE OF ANTIAIRCRAFT MACHINE GUNS.
The use of antiaircraft machine guns against aircraft at a lower
angle of sight than 8°, unless firing into enemy territory, is not
practicable—for the reasons that an aircraft thus sighted, if flying
at normal altitude, would be out of range, and such fire across our
own ground would be dangerous to our own forces.
Firing at aircraft with machine guns of .30 caliber at any greater
distance than 1,300 yards, or meters, has been found to be a useless
waste of ammunition.
4. * SEARCHILIGHTS.
Searchlights are of much importance in antiaircraft work. They
help to keep the enemy aircraft high, make it difficult for them to
aim accurately, and cooperate With our guns by picking out the
hostile machine.
5. WIRELESS INTERCEPTING STATIONS.
Wireless intercepting stations assist in defense by locating air-
planes using wireless. They can follow the movements of the enemy
aircraft, as regards location and direction, so long as it uses its
wireless apparatus, and advise our forces accordingly.
Q
6. LIAISON BETWEEN ANTIAIRCRAFT AND AIR SERVICE.
A close liaison should be maintained between antiaircraft and
air service, the results of thorough liaison during the recent war
having been such as to justify deep and constant effort along this
line.
7. USE OF SMALL ARMS AGAINST AIRCRAFT.
As every unit must be largely responsible for its own protection
against attacks from the air, because our antiaircraft guns and our
aircraft are both limited in their use against very low flying enemy
machines, it is necessary to train machine gunners and riflemen in
effective fire at any hostile aircraft within their range.
Much can be done with small-arms fire, machine gun, and auto-
matic rifle, even though its effect may not be apparent at the time.
Hostile machines are often damaged to such extent that they are
PLATE 4,
º
| - º
|| || º: -
-- ~~ º - - - - -
ºº Sº
- º
- -- - - -
º, -º-º-º-º-
COVER FOR ANTIAIRCRAFT MACHINE GUNS. A. E. F., FRANCE, USING HOTCH KISS
MACHINE GUN ON ITS TRIPOD AGAINST ENE MY AIRCRAFT.
20

ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 21
forced to land. As, however, an airplane at 2,000 feet height has
an area of 12 square miles in which to select a landing place, and
may go 13 miles in any direction before reaching the ground, it is
evident that an enemy aircraft may be put out of action and yet
able to conceal its injury from the attacking party. It is roughly
estimated that an airplane must descend inside a circle having a
diameter of 10 times the height of the machine.
As it is not possible to give in this book detailed instructions for
the conduct of antiaircraft fire under the varying conditions which
are met with, the commander of each unit must direct the use of
its antiaircraft armament to best advantage.
Many factors must be considered in delivering effective fire against
aircraft from the ground. It is obvious that the gunner must shoot
in front of the aircraft to allow for its motion during the time of
flight of the bullet. The sights used in antiaircraft work are de-
vices for assisting the gunner in directing his fire at the proper dis-
tance ahead of the moving target. The speed and range of the air-
plane must be determined and its line of flight noted, quickly and
accurately. Any change in speed or direction which would affect
the sighting must be instantly acted upon. The various means of
deception used by enemy aviators to confuse the gunners must also
be contended with. .
8. USE OF FIRING TIME.
The target of the antiaircraft gunner is usually within range for
only a few seconds and most effective use should be made of that
time. Firing in long bursts—not in short bursts as practiced against
infantry—is considered advisable, as it is usually impossible to tell by
observation what effect the bullets are having and there is great dan-
ger of a break in fire occurring just when most damage might be
inflicted.
9. VISIBILITY – DISTINGUISHING FRIEND FROM FOE.
It is very important that every man engaged in antiaircraft
work should be familiar with the appearance of the various types
of aircraft and able to distinguish friendly from enemy machines.
Experience is necessary to identify the type of an airplane at long
range. It is therefore advisable that the appearance of aircraft of
the various types and nationalities should be studied at every oppor-
tunity. - *
National markings are usually visible to the naked eye at 3,000
feet, if the light and the angle of the machine are favorable for ob-
servation; at the same distance the struts are also visible in side
view. The undercarriage and engine may be seen at 2,500 feet dis-
tance. At 2,000 feet the struts are clear in front view and the pro-
peller, rudder markings, and squadron marks are visible. At 1,000
PLATE 5.
|
Arºor prºod TRACER INCENDIARY ORDINARY.
|
|
|
Mºnºcº Macaº Guº Caº ROC go on
ARMOR-PIERC ING: DISTINGUISHED BY LIGHT GRO OVE AROUND
BULLET. TRACER: DISTINGUISHED BY HAVING BLACK SHELL.
|NCEND ARY: DISTINGUISHED BY HAVING BLACK BULLET.
22









ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 23
feet the heads of the pilot and observer are clear in outline when
the machine is banking; but their features are not distinct. At 500
feet, in good light, the details of the aircraft are clear and the
features of the aviators may be seen.
Great care should be taken to establish the identity of all airplanes.
Identification marks, or cocards, showing the nationality of the
planes will be found near the wing tips on either the under or upper
side. When seen in profile, in general, the only method of identify-
ing the plane, except by silhouette, is by the recognition marking
painted on the rudder. Much time should be spent by antiaircraft
machine gunners in the study of the silhouette of both friendly and
enemy aircraft; and each gunner should have and study frequently
an up-to-date chart showing clearly the silhouette of all the different
types of aircraft.
10. CLOTODS.
Clouds in fine weather are at least 4,000 feet (over 1,300 yards)
above the ground, and aircraft passing through them are out of
range for machine guns of .30 caliber. Rain clouds and the cloud
shreds known as “scud' float as low as 1,500 feet (500 yards) on
Some occasions.
The clouds are often used as screens by skilful aviators, and should
be kept under observation when surprise attack is possible.
11. AMMUNITION: ARMOR-PIERCING, TRACER, AND IN CENDIARY.
As some enemy aircraft are armored, it is customary to use armor-
piercing ammunition mixed with the ordinary service type.
Tracer ammunition is also used, to permit the accuracy of the
fire to be observed. Tracer bullets mark their flight by flaming,
and are visible up to about 500 yards distance, against a favorable
background. They are of about the same weight as the service
bullet and up to 500 yards range have approximately the same
trajectory.
Incendiary ammunition is used against aircraft, with the object
of setting them on fire. The incendiary bullets also act as tracers
to a certain extent. They smoke in their flight and are visible for
about 300 yards. Their trajectory up to 500 yards is practically the
same as that of the service bullet.
Armor-piercing tracer and armor-piercing incendiary cartridges
have been experimentally developed; but are not as yet officially
adopted for general use. -,
Cartridge belts for antiaircraft machine-gun work are filled with
a suitable assortment of armor-piercing, tracer, incendiary, and serv-
ice cartridges; preferably 1 tracer, 1 incendiary, 4 armor-piercing,
and 4 service cartridges in every 10 used. .
24 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
12. TRAINING IN ANTIAIRCRAFT FIRE.
To obtain the utmost value from antiaircraft equipment it is
essential that the officers of each unit concerned should take a live
interest in and encourage to the best of their ability antiaircraft
training. The instructions contained in this book, particularly as
regards the sights used in firing at aircraft, should enable officers to
impart to their command a practical knowledge of this work.
A simple model of an airplane and an ordinary aim corrector will
furnish practical instruction in correct sighting. A special aim
corrector for training antiaircraft machine gunners in the use of
their sights is at present in course of development; but pending its
completion the simple appliances mentioned above will furnish ex-
cellent training. e
A model airplane of the following dimensions, held 10 yards from
the muzzle of the gun, will appear as an aircraft at 1,000 feet
height and 50 degrees angle of sight; that is, at a distance of 1,305
feet, or about 425 yards range:

Type of aircraft. Width of span. Length of body.
2-seater - - - - - - - - - - - - - - 12 inches. . . . . . . . . . 7 inches.
Scout---------------- 8 inches. . . . . . . . . . . 6 inches.
Men may be trained in the correct use of antiaircraft sights in a
very short time; but constant practice in aiming at airplanes is
necessary to obtain the quick action and accurate shooting that is
essential in actual aircraft engagement.
The first instruction, for a period of about one hour, should be
given with a stationary model representing an airplane in any direc-
tion of flight, the student’s aim being checked by the instructor.
When the student is proficient in this practice he should then be
taught how to hold his aim on airplanes in motion, either passing
aircraft or moving models being used for this instruction.
13. SIGHTING GUIDE FOR SMALL ARMS WITHOUT ANTIAIRCRAFT
SIGHTS.
For firing with ordinary service sights at the enemy aircraft
known as “contact patrols,” which attack the men in the trenches
and forward area generally, from heights of about 1,000 down to
150 feet, the following approximate sighting guide may be useful:
For approaching airplane: Set sight at 1,600 yards and aim at the nose of the
airplane.
For crossing airplane: Set sight at 500 yards and aim 14 inches in front of the
noSe Of airplane.
For receding airplane: Set sight at zero and aim # inch below the airplane.
CHAPTEB II.
ANTIAIRCRAFT MACHINE GUN SIGHTS.
INTRODUCTION.
The fact that the accurate direction of antiaircraft fire has as-
sumed the aspect of a science has attracted the attention of numer-
ous minds to the solution of its problems, with a consequent large
variety of designs of instruments for accomplishing the desired
results. The design of sights for antiaircraft machine guns is a
recent development, both abroad and in the United States, having
begun, probably, within the past three years in Europe, and in this
country only since the entry of the United States into the war. It
evidently originated when the necessity for special sights for this
work was made apparent by the first use of machine guns against
aircraft; for undoubtedly the first of these guns fired upward against
enemy airplanes were equipped with regular field sights, the gun-
ners estimating to the best of their ability the amount of “lead "
necessary in sighting to shoot ahead of their target, as in trap-
shooting or hunting.
The control of antiaircraft machine-gun fire differs from the
fire control of large caliber guns in that the range is much less and
the time available for estimating range and firing is very short. In
fact, the use of machine guns against aircraft resolves itself into
roughly estimating the range and line of flight and directing the
gunfire to intercept the target, by means of a sighting arrangement
that will permit direct aim at the target by allowance for its speed
and distance. Shooting at aircraft from the ground. is practically
similar to shooting at birds on the wing; it is necessary to shoot in
front of them to allow for their change of place while the bullet
is on the way.
TREND OF DESIGN.
The trend of design of antiaircraft machine gun sights has been
toward two distinct types: -
1. A fixed front and rear sight based on average conditions (range,
path of flight, altitude, size, and speed of target) on which no me-
chanical adjustments are provided. The common examples of this
class of sights are the “ring sights” used on aircraft guns, and the
- 25
26 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
“forward area,” or “trench sights,” of British design for use on
antiaircraft machine guns.
2. An adjustable sight, embodying some mechanical adjusting
means to meet varying conditions of range, flight, altitude, and speed
of the target. Usually in this class of sights the plane is assumed
to maintain a constant altitude during the firing period, and ad-
justments are made only for its path of flight, range, and speed.
The French developed the “P. B.” and “Corrector” types of sight
for this service and later followed it with the “Peycru” sight.
USE OF THE TWO TYPES OF SIGHT.
As a general rule the fixed sights, such as the “forward area,” are
used against low-flying aircraft in forward areas where the attack is
of such nature that there is no time for any adjustments. The ad-
justable sights, such as the “Peycru,” are used for the defense of
rear areas, where the attacking plane usually flies at a higher alti-
tude and can be seen early enough to permit of better estimation of
the conditions of its approach.
Numerous types and models of sights have been developed and
tested; but the consensus of opinion of the allied armies has been that
the fixed, forward area or trench sight of British type is the best for
the defense of forward areas, and the adjustable Peycru, French,
sight, the best for rear area defense.
It may be noted that no correction is attempted in the design of
these sights for “wind ’’ and “drift” of bullet. The gunner must
learn to apply his own correction for these variable factors. Allow-
ances for the “jump ’’ of the gun and the “angle of fire * are, how-
ever, incorporated in the sight. -
These approved sights which have been developed by practical
study of the use of machine guns against aircraft will later be de-
scribed in detail and as regards their use with each machine gun of
official issue.
THE MAIN FACTORS IN ANTIAIRCRAFT FIRE.
The principal factors which have to be considered in firing at
aircraft are:
1. High velocity of the aircraft.
Direction of the aircraft (changeable).
Short duration of the time for effective fire.
Trajectory of the bullet.
. Velocity and time of flight of the bullet.
. Cone of fire of the machine gun.
Jump of the machine gun.
Drift of the bullet.
:
:
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 27
9. Angle of elevation.
10. Windage.
In design of sights for antiaircraft work these factors must be
taken into consideration. In addition thereto, according to the Zone
of activity for which the sight is required, forward or rear area, must
be considered other factors.
For forward area defense, which implies use of the sight by front-
line forces against low-flying aeroplanes attacking them in trenches,
on roads, as outposts, advanced guards, etc., the additional factors to
be considered in design are:
1. Fixed sights, of which the Trench Sight, British type, is best.
2. Simplicity of operation.
3. Quick attachability and detachability.
4. Noninterference with regular sights.
For rear area defense, which includes the use of machine guns
for the protection of ammunition dumps, depots, hangars, etc., the
gun is semipermanently mounted. For this work the following
factors bear upon the sight design:
1. More weight allowable, because more permanently mounted.
2. Simplicity not so important.
3. Quick detachability not so necessary.
4. Noninterference with regular sights not so essential, as the guns
are primarily antiaircraft.
This grouping of factors requisite in the design of sights is of
recent origin and has only been partially followed in the field use
of sights. * -
The broad classification of antiaircraft machine gun sights is,
as previously stated, that which divides them into:
1. Fixed sights, of which the Trench Sight, British type, is best.
2. Adjustable sights, of which the Peycru, French, sight is best.
In general, fixed sights are those types with either the front or
rear sight consisting of a peephole and the other sight a ring, oval,
or other pattern, which forms a field inclosure in which the target
is positioned for firing, as may be indicated by its path of flight and
distance. The sight remains fixed and the gun is manipulated to
bring the target to the desired position in the sight field. The fixed
sight is generally, and necessarily, a compromise between the variable
factors which bear upon its design. It is made to meet approximately
the average conditions of use, being designed for shooting at an
average angle of fire at aircraft traveling at average speed and alti-
tude. The sight which positions the target may, as stated, be either a
front or rear sight, and a division of opinion exists as to which is the
better location for it; the weight of opinion is, however, in favor
of its use as the front sight. Fixed sights are favored for forward
28 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
area use because of their simplicity and ease of use by slightly
trained personnel.
Adjustable sights usually consist of a more complicated Set, of
which one sight, generally the rear, is adjusted by hand, inde-
pendently of the gun, in order to secure the desired sighting. This
necessitates greater facility and skill on the part of the gunner, re-
quiring additional training. The other sight, generally the fore
sight, is either fixed, or automatically adjusted without manipulation
by the gunner. Although the adjustable type of antiaircraft ma-
chine-gun sights is more complicated than the fixed type, the finer
approximations of the sighting factors and more accurate firing that
can be obtained by its use, compensate for its lack of simplicity. Ad-
justable sights are favored for the defense of rear areas, for the rea-
sons that the personnel there can be specially trained in their manipu-
lation, and firing can be done more deliberately because of the greater
height and earlier discerned approach of the enemy aircraft.
PRACTICAL SIGHT DESIGN AND SIGHTING FACTORS.
The design of antiaircraft machine-gun sights is usually based on
the factors of target indication that are known to be most commonly
met with in the field.
The sights are so designed, with a series of Sighting points marked
on the speed allowance sight, that when a line of sight is established
• from the gunner's eye through or over the aligning sight and across
one of the offset sighting points to the target, the gunfire will be
deflected at the proper angle to allow for the forward motion of the
target and intercept it in its path of flight. -
In the case of a fixed sight, the angle of fire deflection, or amount
of firing ahead of the target, which is thus obtained, depends upon
the radial dimension of the pattern sight, which is primarily de-
signed for effective fire under average conditions against a plane
traveling 100 miles per hour, at 1,000 feet height and 50° angle of
sight, or 120 miles per hour, at 200 feet altitude and 15° angle of
sight. As, however, the distance between front and rear antiaircraft
sights on a machine gun may be decreased by sliding one sight
closer to the other along the barrel of the gun, the angle of fire de-
flection may be thus increased, under the direction of a competent
officer, to adapt a fixed sight for direct aim on planes traveling at
higher speeds than those for which it is designed as normally
mounted.
The factors generally considered most important are: The speed
of the plane; its direction; its height above the gun; the angle of
elevation of the gun; the time of flight of the bullet and its tra-
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 29
jectory. It will be apparent that it is very difficult to determine
these factors accurately in the field and that even if possible to do so
they would need to be determined instantaneously, because most of
them are constantly changing, as the target varies in Speed, height,
or direction. Another factor to be remembered in this connection is
that of the time necessary to manipulate the gun into proper posi-
tion, which would need to be done while the target indication held
good. It is obvious that antiaircraft machine-gun sighting must
necessarily be approximate. Therefore, definite sets of target indi-
cations are incorporated in the design of sights, the nearest approxi-
mation to the actual conditions being chosen by the gunner. The
error is, of course, recognized; but its actual effect is practically
nullified by the vibrations of the gun and mount, and the rapidity
of fire, which produce a cone of fire of such volume that effective
fire may actually be established. Results in the field justify the
practice which has been followed in sight design.
Although the use of machine guns against aircraft is new, the
number of planes so brought down in recent fighting has been con-
siderable and encouraging, when the fire has been used within its
proper zone of effectiveness, generally considered to be against air-
craft within 2,000 feet height and at 15° or more elevation. The
limit of range for effective fire by machine guns at aircraft has been
found to be 1,300 yards. Firing at planes at greater distance, with
Small arms ammunition of the present power, is ineffective and
wasteful.
- PLATE 6.
Front sight. Rear sight.
TRENCH SIGHT, ANTIAIRCRAFT (FRONT AREA SIGHT), SHOWN AS MOUNTED
ON A MARLIN TANK MACHINE GUN, FRONT SIGHT UPRIGHT.
30

PLATE 7.
Front sight completely turned down and spring
- plunger pin returned to normal position.
Front sight partly turned down; released by
pulling back spring plunger pin.
TRENCH SIGHT, ANTIAIRCRAFT (FRONT AREA SIGHT) FRONT SIGHT ONLY, AS
- USED ON MARLIN TANK MACHINE GUN. SHOWING. HOW THE FRONT SIGHT
IS TURNED DOWN ON GUN BARREL WHEN NOT IN_USE.
152535–20–3 31



CHAPTER III.
TRENCH SIGHT, ANTIAIRCRAFT.
(Front Area Antiaircraft Sight.)
(Plates 1, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 28, 31, 33, 36, 37, 41, 43,
44, 46, 47, 49, 54, 61.)
A. THEORY-MATHEMATICS.
The time of flight of the bullet is an important factor in anti-
aircraft firing, because of the remarkably high speed of the airplane.
The outer sighting oval of the Trench Sight is designed for an air-
plane traveling 100 miles per hour at 1,000 feet above the ground
and 50° angle of elevation from the gun, as in the following diagram.
|
ſ
! G = GUN
|000 FEET A = ARPLANE
| R = RRNGE
|
4
PLATE 8.
It will be seen that an aircraft at 1,000 feet height and 50° angle
of elevation is 1,305 feet distant. From tables in the United States Rifle
Handbook the time of flight of the bullet for 1,305 feet is 0.604
second. In this time the airplane at 100 miles per hour will travel
88.6 feet. The Trench Sight has been so designed that a bullet will
meet in its new position an aircraft at this assumed normal speed,
height, and angle, presuming that the direction and altitude of the
aircraft do not change during the time of flight of the bullet. This
has been accomplished by the use of an oval frame as front sight, of
such design and dimensions that an aircraft viewed through an
aperture backsight as just touching with its nose the outer rim of the
oval and traveling toward its center will be intercepted in its flight
by the bullet. The Trench Sight, front sight, consists of two such oval
frames, one inside the other; the inner oval is designed for aircraft
at closer range, higher speed, and lower elevation angle; assumed
conditions being 200 feet height, 120 miles per hour speed, 15° angle
of elevation. The rear sight is simply a peephole of arbitrary size
through which the oval frame front sight is sighted on the aircraft.
The front and rear sights are mounted on the machine gun at a fixed
32

ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNs. 33
distance apart, the sight radius and name of gun for which intended
being marked on each front sight. -
To determine the size and shape of the front sight for the chosen
sight radius, or distance between front and rear sights, the move-
ment of an aircraft at the assumed normal heights, speeds and angles
of elevation, in all directions from a central spot, was reduced to the
apparent movement on the plane of the front sight, measured from
its center. Corrections were made for the trajectory of the bullet
and the jump for the type of gun on which used and incorporated in
the design. The result was the oval shape of the sight.
A B
AIRPLANE GOING }>
|OOO FEET
>
RIRPLANE CONTING < …ºf
|OOO FEET
º
|
ſ
!
|
l
|
t
|
|
Y
RS
RS = REAR SIGHT º
FTS = FRONT SIGHT -
A = POSITION OF PLANE WHEN TRIGGER PULLED
B = POSITION OF PLANE WHEN BULLET STRIKES
A = POSITION OF PLANE ON FRONT SIGHT WHEN TRIGGER PULLED
B = POSITION OF PLANE ON FRONT SIGHT WHEN BULLET STRIKES
PLATE 9.
The direction of flight of an aircraft has considerable effect upon
its apparent movement, a fact duly taken into account in the sight
design. The aircraft may be going directly across the line of sight,
from right to left or left to right, or coming directly toward or
going directly away from the gun; or, what is more often the case,
going or coming diagonally. Whichever way the aircraft may be
moving, as seen by the gunner's eye through the sights, it will appear
to be rising on the plane of the front sight if it is coming nearer or
falling if it is going away, even though actually at the same height
above the ground. This is due to perspective and is explained in the
following diagram. When the aircraft is flying directly across the
front of the gun it will appear to neither rise nor fall but describe a
horizontal line across the sight.


34 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNs.
B. GENERAL DESCRIPTION.
The sight is a simple device making possible with very little train-
ing effective fire against aircraft by machine guns. It is of the fixed
type of antiaircraft sight and has been adopted by both the British
and United States Armies for forward area defense. As explained
above, it is designed to make correction for the displacement of the
fast-moving aircraft target, at the estimated normal height, speed,
and angle, at the nearer ranges, in which aircraft operate in the for-
ward area of the battle front.
As shown in the several plates accompanying the instructions in
the following pages for the various adaptations of the sight for dif-
ferent guns, the Trench Sight consists of a rear peep sight attachable
to the regular rear sight leaf, or other part near the breech of the
gun, and a concentric double oval front sight of plate metal mounted
on a suitable Support and clamped around the barrel, radiator, or
water jacket of the machine gun, and readily detachable therefrom.
The parts are all metallic and protected with a black rustproof
finish.
C. GENERAL DIRECTIONS FOR USE.
The sights, front and rear, are attached to the gun at the correct
sight radius. The name of the gun for which designed and the
sight radius are marked on each front sight. In measuring sight
radius take the distance from the face of the front sight to the face
of the rear sight. See that the front sight is vertical to the barrel
of the gun. Clamp the sights snugly in place, so that they will
maintain their proper position.
With the sights properly attached and at the correct distance apart,
the gunner sights through the rear peephole across rim of front oval
at the flying target and shifts the line of the gun toward same,
so that the aircraft will constantly appear to be flying directly
toward the center of the front sight. Generally this will require
almost constant changing in the aiming of the gun, as the aircraft
seldom fly long without changing direction.
Given the altitude of the aircraft by the observer, the gunner
chooses the oval which more nearly approximates the range. He
then fires when the nose of the target just touches the outer edge
of the oval chosen and continues to fire, in as long bursts as prac-
ticable, while changing the line of the gun to maintain always the
same relative position of the aircraft and the front sight—that is,
to have the aircraft always flying toward the center of the sight
with its nose just touching the rim of the oval used.
As expertness is acquired by practice, the gunner may use an
imaginary sighting oval between or outside of the two ovals of the
front sight, in cases where the altitude or speed of the aircraft
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 35
renders such action of advantage. Also, as no allowance for windage
has been made in the construction of the sight, the gunner may
arbitrarily correct for this factor when the wind velocity and direc-
tion warrant it.
The front sight may be turned down on the gun when not in use,
and the regular sights of the gun used, if required. Whether upright
or turned down the front sight is locked in position by a spring
Snap which holds it against the vibrations of the gun.
As the sights are made light in weight, and have no protecting
guards, care should be taken in handling them. They should be
detached when out of use for any length of time and carried in the
case provided. The same care and attention should be given them
to preserve their accuracy and serviceability as is required by any
other delicate part of the gun. They should be cleaned and oiled
whenever necessary to prevent rust and wear.
36 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
Sº?
º
SE;
8 9
2, 3, \2.
PLATE 10.-Correct and incorrect aiming with the Trench Sight, Antiaircraft. The circle
inclosing the airplane and section of front sight represents the rear sight aperture.
CORRECT AND IN CORRECT AIMING WITH THE TRENCH SIGHT.
(I'ront Area Antiaircraft Sight.)
(Plate 10.)
Fig. 1. Outer ring in use (altitude 500 to 3,000 feet). CORRECT. The air-
plane is flying toward the ring center, the nose of the airplane is
touching the outer edge of the ring being used, and the point where
the nose of the airplane touches the Outer edge of the ring is Centered
in the back-sight aperture.
Fig. 2. Outer ring in use (altitude 500 to 3,000 feet). INCORRECT. The air-
plane, while touching the outer edge of the ring being used, is not
flying toward the ring center. The bullets will pass below the target.
Fig. 3. Outer ring in use (altitude 500 to 3,000 feet). IN CORRECT. The nose
Of the airplane is not touching the Outer edge of the ring, although it
is flying toward the ring center. If fire were opened on this sighting
the bullets would pass in front of the target. -
Fig. 4. Outer ring in use (altitude 500 to 3,000 feet). INCORRECT. The air-
plane is flying away from, instead of toward, the ring center. Iłul-
lets would pass a long way behind the target.








ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 37
Fig. 5. Outer ring in use (altitude 500 to 3,000 feet). INCORRECT. The nose
of the airplane is not touching the Outer edge of the ring being used ;
but has passed inside that ring, too close to the ring center. On this
sighting fire would be opened too late and the bullets would pass
behind any vital part of the airplane.
Fig. 6. Either outer or inner ring in use. INCOI&RECT. The airplane is not
flying toward ring center, the nose is not touching the outer edge of
ºring being w860, and the point where the nose of airplane would
touch either ring is not centered in the back sight. The bullets Would
pass in front and to the left of the airplane.
Fig. 7. Outer ring in use (altitude 500 to 3,000 feet). IN CORIEECT. The
point where the nose of the airplane touches the outer edge of the
ring used is not centered in the back sight aperture. Even though
the airplane is flying toward the ring center and touching the ring
edge properly, the point of nose contact being off Center Will CauSe
the bullets to pass in front of the airplane.
Fig. 8. Center aperture in use. CORRECT. The airplane is diving toward
the gun. Aim is taken by aligning the ring center aperture, Centered
in the back sight aperture, upon the middle of the upper part of the
plane. The bullets will then hit the vital parts of the airplane.
Fig. 9. Inner ring in use (up to 500 feet). CORRECT. The airplane is flying
toward the center of the ring, the nose of the airplane is touching
the outer edge of the ring being used, and the point of contact be-
tween the nose of the airplane and the outer edge of the ring used is
centered in the back sight aperture.
Fig. 10. Inner ring in use (up to 500 feet). INCORRECT. The nose of the
airplane is not touching the outer edge of the ring being used. The
bullets would pass in front of the target.
Fig. 11. Inner ring in use (up to 500 feet). IN CORRECT. The airplane is
not flying toward the ring center. The bullets would pass to the
right of the airplane. -
SIGHT, ANTIAIRCRAFT, TRENCH. F3; howning AUTOMATIC RIFLE, MODEL
- 918.
(Front Area Antiaircraft Sight.)
(Plates 11, 35.)
1. Directions for attaching.—Remove the sight from its carrying
case. The rear sight replaces the regular rear sight slide of the
rifle. Remove the small stop screw near the upper end of the rear-
sight leaf, and pressing on the thumb piece, or slide catch, remove the
slide. Replace it with the rear sight of the trench sight and replace
the stop screw. -
To attach the front sight, remove the clamping bolt and crown nut
from the front-sight brackets. Spread the brackets apart at the bolt
end and pass the open end of the lower bracket through the opening
between the barrel and the gas cylinder tube bracket, passing it in
af
ANTIAIRCRAFT MATERIEL FOR MACHINE GUNS.
38
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ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 39
from the left side so that the holes for the bolt will appear at the
right side. Press the brackets together loosely around the barrel
and insert the clamping bolt up through the holes and through the
crown nut down from the top. Hold the front sight up approxi-
mately vertical and, while pressing it forward against the gas
cylinder tube bracket, tighten the nut until the sight will stick in
position but may be turned by pressure from the hand. Then make
it exactly vertical by sighting through the rear sight and bringing
the center screw in line with the front sight. Tighten the bolt Se-
curely and the sight is ready for use. *
2. Directions for use.—Keep the rear-sight slide at the top of the
leaf and the leaf upright. Keep the front sight vertical, locked in
its upright position by the Snap plunger at its right side. See that
the front-sight base brackets are kept pressed against the rear of the
gas cylinder tube bracket; when this is the case the correct sight
radius, or distance between front and rear sights, will be maintained.
The general instructions for sighting given in Part C of this
chapter should be followed.
When the sights are out of use they should be folded down on the
barrel.
List of parts, Sight, Amtiaircraft, Trench (British type) (2/.2-inch or 25-inch
sight radius). Browning Automatic Rifle, Model 1918.
(Front Area Antiaircraft Sight.)
Number
No. - Name of part. required.
**-*...*
Bolt, 0.25 inch by 0.812 inch (+4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight----------------------------------------------------------------------------
Front sight bracket (upper). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Sight bracket (lower). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight stop----------------------------------------------------------------------.
Nut Crown, 0.25 inch. -----. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin, Steel, 0.05 inch by 0.275 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin for front Sight bracket. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 || Pin, Split, 0.046 inch (#) by 0.312 inch (4%). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11 | Rear Sight slide------------------------------------------------------------------------
12 | Rear Sight slide catch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13 | Rear Sight slide catch Spring. . . . . . . . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
14 Screw, fillister head, 0.125 inch by 0.187 inch (†). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15 Screw, countersunk head, 0.125 inch by 0.187 inch (#). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16 || Spring--------------------------------------------------------------------------------.
17 | Spring plunger----------------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18 Spring plunger cap.----------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NOTE.-New design of this sight in progress.
SIGHT, ANTIAIRCRAFT, TRENCH, FOR BROWNING MACHINE GUN, MODEL OF 1917.
(Front Area Antiaircraft Sight.)
(Plates 12, 1, 31, 33, 36, 41, 46.)
1. Directions for attaching.—The rear sight consists of a special
rear-sight slide with a large-size peephole, which replaces the regular
slide.
zº
ANTIAIRCRAFT MATERIEL FOR MACHINE GUINS.
40
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ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 41
The front sight consists of the front sight, support, and clamping
bracket to attach the sight about the water jacket of the gun.
To put on the rear sight, remove the regular sight slide by remov-
ing the large and small cap screws; assemble the half nut, spring,
etc., into the trench sight rear slide; place this under the leaf and the
regular slide cap over the leaf and return the screws.
To apply the front sight, remove the clamping nut and bolt;
spread the two parts of the band around the water jacket, with the
pin hinge to the left, and the bolt to the right side. Press the sight
band around the water jacket; insert the bolt up from the bottom
and screw down the clamping nut from the top. Holding the sight
approximately vertical, slide it along the water jacket to the proper
distance from the rear sight for the sight radius, as marked on the
metal of the front sight. Measure this distance from the face of
the rear sight, upright, to the face of the front sight, upright.
Tighten the clamping bolt so that the sight will stick in this posi-
tion, but may be turned about the water jacket by pressure. Looking
through the rear sight bring some central point on the front sight
in line with the regular front sight of the gun. Then tighten the
bolt to clamp the sight securely. The sight is ready for use.
2. Directions for use.—To use the sight, keep the rear sight slide
at the bottom of the leaf and the front sight vertical, locked in its
upright position by the spring plunger at its right side. See that
the sight radius is always maintained at the correct length.
The general instructions for use of the sight, given in Part C of
this chapter, should be followed.
List of parts, Sight, Antiaircraft, Trench (British type) (24.2-inch or 25-inch
sight radius). Browning Machine Gun, Model of 1917.
(Front Area Antiaircraft Sight.)
Number
T
No. Name of part. required.
Bolt, 0.25 inch by 1937 inches (1++)..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Crown nut, 0.25 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clamp block (upper). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * * * * * * * * * * *
Clamp block (lower). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight bracket. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight Support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight stop... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin for front sight bracket... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin, split, 0.046 inch (ºr) by 0.312 inch (*). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear sight aperture disk pivot Screw. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12 | Rivets, 0.125 inch by 1 inch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rivets, 0.125 inch by 0.427 inch (ºs). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rivets, 0.125 inch by 0.812 inch (#). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13 | Rear sight slide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14 | Rear slide cap... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15 | Strap hinge (upper). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16 | Strap hinge (lower)..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17 | Screw, fillister head, 0.125 inch by 0.187 inch (ºs). . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . .
Screw, fillister head, 0.125 inch by 0.312 inch (ºs). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • * *
18 || Spring. . . . . . . . . . . . . . . . . . . . . . . . . . . . -------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . .
19 || Spring plunger. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20 | Spring plunger cap. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
;
NOTE.-New design of this sight in progress.
34.675
mir
:
f
PLATE 13.−Trench Sight, Antiaircraft, for Vickers Machine Gun, Model of 1915.
(Front Area Antiaircraft Sight.)
*


ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNs. 43
sight, ANTIAIRCRAFT, TRENch, for vickers MACHINE GUN, Model of 1915.
(Front Area Antiaircraft. Sight.)
(Plate 13.)
1. Directions for attaching.—The rear sight consists of a special
rear-sight slide cap with a large-size peephole, to take the place of
the regular cap.
The front sight consists of the front sight, support, and clamping
bracket or band, to attach the sight about the water jacket of the gun.
To place the rear sight in position, remove the regular sight slide
by removing the large and small cap screws; assemble the half nut,
spring, etc., into the trench sight rear slide; place this under the
leaf; place the regular slide cap over the leaf and return the screws.
To attach the front sight, remove the clamping nut and bolt;
spread the two parts of the band and place it encircling the water
jacket, with the pin hinge to the right and the bolt to the left side.
Press the band about the water jacket; insert the bolt up from the
bottom and turn down the clamping nut from the top. Holding
the sight approximately vertical, slide it along the water jacket to
proper sight radius distance, as marked in the metal of the front
leaf. Measure this distance from the face of the rear sight, upright
to the face of the front sight, upright. Tighten the clamping bolt
so that the sight will stick in position but may be turned around
the water jacket by pressure. Looking through the rear sight bring
a central point on the front sight in line with the regular front
sight of the gun. Then tighten the bolt to clamp the sight securely
in vertical position. The sight is ready for use. •
List of parts, Sight, Antiaircraft, Trench (British type) (34.875-inch or 25-inch
sight radius). Wickers Machine Gun, Model of 1915.
(Front Area Antiaircraft Sight.)
Number
required.
N
O,
Name of part.
Bolt, 0.25 inch by 1.937 inch (1+$) . . . . . . . . . . . . . . . . . .* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Front sight.------------------------, - . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight bracket. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight stop---------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nut, crown-----------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin for front sight bracket... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin, Split, 0.046 inch (ºr) by 0.312 inch (ºs). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear sight aperture disk pivot Screw. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 | Rear sight slide. . . . . . .- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
11 | Rear slide cap... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12 | Rivets, countersunk head, 0.125 inch by 0.437 inch (I's). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13 | Screws, fillister head, 0.125 inch by 0.187 inch (ºs). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14 | Serows, fillister head, 0.125 inch by 0.312 inch (ºr). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15 | Strap hinge (lower). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16 | Strap hinge (upper). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17 | Clamp block (lower). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1S º block (upper)--------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19 || Countersunk head rivets, 0.125 inch by 0.812 inch (+$). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20 | Countersunk head rivets, 0.125 inch by 0.875 inch... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21 | Spring---------------------------------------------------------------------------------
22 | Spring plunger. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23 Spring plunger cap. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EL FOR MACHINE GUNS. .
a'
ANTIAIRCRAFT MATERI
44
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ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNs. 45
2. Dºrections for use.—In using the sight, keep the rear sight slide
at the bottom of the leaf and the front sight vertical, locked in its
upright position by the spring plunger at the right side. See that
the correct sight radius is always maintained.
Follow the general instructions given in Part C of this chapter
for use of the sight and its care and preservation.
SIGHT, ANTIAIRCRAFT, TRENCH, FOR LEWIS MACHINE GUN, MODEL OF 1917.
(I'ront Area Antiaircraft Sight.)
(Plates 14, 43, 28.)
1. Džrections for attaching.—The rear sight consists of the rear
sight, an L-shaped forging, and its horizontal base, shaped to pass
into the back sight leaf of the gun; a rear sight screw to hold the
sight to the leaf, and a rear sight nut to tighten the screw.
The front sight consists of the front sight leaf, support, bracket,
and a two-part circular clamp band to encircle the radiator casing.
To attach the rear sight, set the regular back sight slide of the gun
down toward the bottom of the leaf; dismount the trench rear sight
from its Screw and nut; place the rear sight aperture piece against
the top face of the gun sight leaf; with the tongue in the opening of
the leaf and pressed up to the top of the opening, the peephole above
the leaf top and on the leaf face toward the eye. Insert the screw
through the leaf into the aperture piece, from the back of the leaf,
pressing the cross head against the leaf back; screw the nut into place
on the screw end and tighten, it so that the rear sight is clamped
Securely in place.
To attach the front sight, remove the clamping nut and bolt;
spread open the two hinged parts of the band and clasp it around
the radiator casing, with the pin hinge to the right and the bolt to
the left side. Press the free ends of the band together, insert the
clamping bolt from the bottom and screw down the nut from the
top. Holding the sight approximately vertical, slide it along the
radiator casing to the proper sight radius distance from the rear
sight, as marked in the metal of the front sight. Measure this dis-
tance from the face of the rear sight, upright, to the face of the
front sight, upright. Tighten the clamping bolt so that the sight
will stick in this position but may be turned about the radiator cas-
ing by pressure. Looking through the rear sight, bring a central
point on the front sight in line with the regular front sight of the
gun. Then tighten the bolt to clamp the sight securely in vertical
position. The sight is ready for use.
2. Directions for use.—In using the sight, keep the rear sight slide
of the gun at the bottom of the leaf, and the leaf upright; keep the
front sight vertical, locked in its upright position by the spring
*3.
*
PLATE 15.—Trench Sight, Antiaircraft, for Marlin Aircraft Machine Gun, Model of 1917.
(I'ront Area Antiaircraft Sight.)
º
^



ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNs. 47
plunger at the right side. See that the correct sight radius is main-
tained.
Follow the general instructions for use of the sight given in Part C
of this chapter.
List of parts, Sight, Antiaircraft, Trench (British type) (25-inch sight radius).
Lewis Machine Gum, Model of 1917.
(Front Area Antiaircraft Sight.)

Number
required.
N
O
Name of part.
Bolt, 0.25 inch by 1.937 inches (1+$)...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clamp block §: * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * s sº e º s ºs = e, e = * * * * * * * * * * * * * * * * * * * * *
Clamp block (upper)-------------------------------------------------------------------
Front sight-----------------------------------------------------------------------------
Front sight bracket. . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Front sight Support------------------------------------------. . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight stop-----------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nut, crown, 0.25 inch------------------------------------------------------------------
Pin for ſront sight bracket.------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 || Pin, split, 0.046 inch § by 0.312 inch (ºs). . . . . . . . . . . . . . . . . . . ., - - - - - - - - - - - - - - - - - - - - - - - - -
11 || Pin, Split, 0.062 inch (ºs) by 0.75 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12 | Rear sight-----------------------------------------------------------------------------
13 | Rear sight screw. ----------------------------------------------------------------------
14 | Rear sight mut-------------------------------------------------------------------------
15 Rivets, steel, countersunk head, 0.125 inch by 0.437 inch (ºs) . . . . . . . . . . . . . . . . . . . . . . . . . . .
16 Rivets, steel, countersunk bead, 0.125 inch by 0.812 inch (#) . . . . . . . . . . . . . . . . . . . . . . . . . . .
17 | Rivets, steel, countersunk head, 0.125 inch by 1 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18 Screws, countersunk head, 0.125 inch by 0.187 inch (ºr). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19 Screws, fillister head, 0.125 inch by 0.187 inch (#). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20 | Strap hinge (lower)--------------------------------------------------------------------
21 | Strap hinge (upper)-----------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -----------
22 | Spring---------------------------------------------------------------------------------
23 Spring plunger---------------------. . . . . . . . . . . . . . . . . . . . . . ------------------------------
24 Spring plunger cap---------------------------------------------------------------------
SIGHT, ANTIAIRCRAFT, TRENCH, FOR MARLIN AIRCRAFT MACHINE GUN, MODEL
OF 1917.
(Front Area Antiaircraft Sight.)
(Plate 15.)
1. Directions for attaching.—The rear sight consists of a plate with
the peephole at the top and the bottom flanged to fit about the front
end of the lock container; also a screw, nut, and lock washer to
fasten the rear sight to the gun.
The front sight consists of the front sight proper, the support,
bracket, band, and set screw with lock nut. --
To attach the rear sight, fit the flange piece with flanges toward
the rear, peephole at the top, vertically about the forward end of
the lock container (old style). Adjust the rear sight vertically so
that the screw hole will align with the hole in the vertical lug at the
forward end of the lock container. Press the screw in through the
holes from the rear. Put on the lock washer and tighten the nut on
the screw so as to hold the rear sight securely in position.
To attach the front sight, loosen the clamping bolt and crown nut,
spread the brackets apart at the bolt end and slide the front sight
over the front end of the gun barrel with hinge pin to the left side
and bolt to the right. Hold the sight leaf approximately vertical
152535—20—4
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
48
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ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 49
and slide the sight along the gun barrel to the proper distance from
the rear sight to give the correct sight radius, as stamped in the metal
of the front sight oval. Measure the sight radius from the face of
the rear sight, upright, to the face of the front sight, upright.
Tighten the clamping nut so that the sight will stick in position but
may be turned about the barrel by pressure. Then adjust the sight
into vertical position by sighting through the rear sight peephole
and moving the front sight into the center of the field of vision.
Tighten the nut to hold the sight securely in position. It is then
ready for use. -
2. Directions for use.—In using the sight, keep the rear sight
firmly held in position by tightening the nut and screw, as necessary.
Reep the front sight in its upright position, locked there by the
spring plunger at the right side, and securely clamped against move-
ment around or along the gun barrel. -
Follow the general directions for use given in Part C of this
chapter.
List of parts, Sight, Antiaircraft, Trench (British type) (25-inch sight radius).
* < ..., Marlin Aircraft Machime Gum, Model of 1917.
(Front Area Antiaircraft Sight.)
Number
required.
N
O.
Name of part.
Brºket hinge pins----...-:::----------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bolt, tap, 0.25 inch by 0.562 inch (T's). . . . . . . . . . . . . . . . . . . . . • * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Front sight---------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight bracket (lower)...... . . . ‘. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight bracket (upper). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight support.-------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front º Stop---------------------------------- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 Nut, 0.19 inch--------------------------------- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
| 9 || Pin, split, 0.046 inch (ºr) by 0.312 inch (º)... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 || Pin, split, 0.062 inch (ºr) by 0.312 inch (ºs)... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11 ! Pin for front sight bracket.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12 | Rear sight...... . * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
13 | Rear sight, flat fillister head screw...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14 Screws, countersunk head, 0.125 inch by 0.187 inch (ºs).... . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15 Screws, flat fillister head, 0.125 inch by 0.187 inch (†). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16 Spring------------------------------------------------------. . . . . . . . . . . . . . . . . . . . . . -- - - - -
17 | Spring plunger---------------------------. . . . . . . . . . . . . . . . . . . . . --------------- . . . . . . . . . .
1S Spring plunger cap. . . . . . . . . . . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Washer, lock, 0.190 inch------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
*
20 | Washer, lock, 0.25 inch.... . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
SIGHT, ANTIAIRCRAFT, TRENCH, FOR MARLIN TANK MACHINE GUN, MODEL OF 1918.
(Front Area Antiaircraft Sight.)
(I’lates 16, 6, 7, 43, 49, 54.)
1. Directions for attaching.—The rear sight consists of a plate
with the peephole at the top and the bottom flanged to fit about
the front end of the lock container; an attaching screw; a nut; a
lock washer. -
The front sight consists of the front sight proper; an oval leaf;
a support bracket; a radiator encircling band; a set screw with a
lock nut.
50 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUINS.
To attach the rear sight, hold it vertical, with the peephole at
the top, and fit its flanged lower end about the forward end of the
lock container of the gun, adjusting so that the screw hole aligns
With the hole in the lug at the forward end of the lock container.
Then put the screw through the holes from the rear side, its head
facing the eye; put on the lock washer and nut; tighten the nut
down on the screw until the rear sight is securely clamped in
position.
To attach the front sight, loosen the lock nut and unscrew the
Set screw until its point is clear of the inner surface of the radiator
band; slide the band over the forward end of the radiator, first
removing the regular front sight of the gun from its place by taking
out the screws holding it; move the front sight along the radiator,
oval leaf upright and locking spring plunger at the right side of
gun, until at the proper sight radius distance from the rear sight,
as marked in the metal of the front sight oval. Then tighten the
set Screw until the band is securely clamped in position on the
radiator, with the oval sight leaf vertical and in line with the rear
sight and gun barrel; tighten the lock nut. The sight is then ready
for use. .
2. Directions for use.—In using the sight keep the front and rear
sights correctly positioned, tightening screws and nuts as often as
may be necessary. Reep the front sight in vertical position, as
locked there by the spring plunger at its right side, and see that it
stays in correct sighting alignment. When sights are out of use
for any length of time, turn the front sight oval leaf down on the
radiator.
Follow the general directions for use of the sight given in Part
C of this chapter.
List of parts, Sight, Antiaircraft, Trench (British type) (25-inch sight radius).
Marlin Tank Gum, Model of 191S.
(Front Area Antiaircraft Sight.)

Number
required.
N
O,
Name of part.
Front sight-----------------------------------------------------------------------------
Front sight band.----------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight bracket------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight support.------------------ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight stop-------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight brace------------- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lock Washer, 0.19 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nut, 0.19 inch... ------------------- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nut, 0.375 inch -------------------------------------------------------------------------
10 || Pin for front sight bracket.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - - - - - - -
11 | Rear sight------------------------------------------------------------------------------ ſ
12 | Rear sight flat ſillister head screw. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13 | Rivets, 0.125 inch by 0.437 inch (I's) countersunk head.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14 || Screws, fillister head, 0.125 inch by 0.187 inch (ºs)... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15 Screws, countersunk head, 0.125 inch by 0.187 inch (ºr)..... . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16 | Set Screw, 0.375 inch by 1 inch (Cup point).-------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17 | Spring----------------------------------------------------------------------------------
18 || Spring plunger-------------------------------------------------------------------------
19 || Spring plunger cap:--------------------------------------------------------------------
20 | Pin, split, 0.046 inch (ºr) by 0.312 inch (*). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 51
SIGHT, ANTIAIRCRAFT, TRENCH, FOR HOTCHKISS MACHINE GUN, MODEL OF 1914.
(Front Area Antiaircraft Sight.) .#
(Plate 17.)
1. Directions for attaching.—The rear sight consists of the rear
sight proper, a bracket, two screws, and one nut. It is a thin plate
with the peephole near the top and the lower end flanged around a
lug on the top of the bracket, to which it is held by a screw. The
bracket is an inverted U-shaped piece with its ends hooked, to engage
the under side edges of the breech cover of the gun, over which it
slides. A vertical set screw with a lock nut bears down against the
top of the breech cover through the arch of the bracket.
The front sight consists of the oval sight leaf; its support; upper
and lower mounting brackets hinged together; a clamping bolt and
nut.
To apply the rear sight, slide back the breech cover of the gun until
the rear sight base bracket can be saddled on it, its leg hooks engag-
ing the lower edges of the cover, if necessary, first loosening the
bracket set screw. Then set the breech cover back in place on the
gun; slide the rear sight bracket as far forward as it will go, butting
against the recoil blocks on both sides; turn down the set screw
against the breech cover top until the bracket is securely clamped in
position and tighten the lock nut. If the aperture part of the rear
sight is detached, place its flanged lower end around the lug on top
of the bracket, with the screw holes in lug and aperture piece in line,
and insert and tighten the attaching screw.
To attach the front sight, loosen the clamping nut and bolt; spread
the hinged upper and lower brackets apart; holding the sight with
leaf vertical and facing rear sight, pass the lower bracket around the
barrel behind the gas cylinder support, through the opening between
barrel and cylinder; close the bracket about barrel, hinge at the left
side, bolt at the right; insert the bolt and screw down the clamping
nut from the top; slide the brackets forward until touching the gas
cylinder support. Then tighten the nut so that the sight will stick
in position but can be turned by hand, and sighting through the rear
sight bring the center of the front sight in line with the regular front
sight of the gun. Tighten the nut until the sight is securely clamped
in position. It is now ready for use.
2. Directions for use.—In using see that the front sight is vertical
and locked in upright position by the spring plunger at right side.
See that both front and rear sights are always rigidly clamped in
proper position, tightening nuts whenever necessary. When the
front sight upper bracket is butting against the rear of the gas cylin-
PLATE 17–Trench Sigh
t, Antiaircraft, for Hotchkiss Machine Gun, Model of 1914.
(Front Area Antiaircraft Sight.)
N

ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 53
der support and the rear sight bracket against the recoil blocks, the
proper sight radius is maintained between front and rear sights.
Follow the general directions for use given in Part C of this
chapter.
List of parts, Sight, Antiaircraft, Trench (British type) (25-inch, 8ight radius).
Hotchlciºs Machine Gun, Model of 1914.
(Front Area Antiaircraft Sight.)
Number
No. - - Name of part. required.
1 | Bolt, 0.25 inch by 0.812 inch (#)------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ------
2 : Check nut, 0.25 inch--------------------------------------------------------------------
3 | Front sight--------------------------, - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
4 | Front sight Support --------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 | Front sight bracket (upper)--. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 | Front sight bracket (lower)---------------------. . . . . . . . . -- . . . . . . . . . . . . . . . . . . . . . . . . . - - - -
7 | Front Sight stop.------------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 || Nut, Crown, 0.25 inch...... . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
9 Pin, steel, 0.187 inch § by 1.125 inch.---------------------------. . . . . . . . . -------------
10 || Pin for front sight bracket-----------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11 Pin, split, 0.046 inch (ºr) by 0.312 inch (#). . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
12 || Pin, split, 0.062 inch (ſº) by 0.75 inch...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - - - - - - - - - -
13 | Rear sight------------------------------------------------------------------------------
14 | Rear sight bracket--------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15 Screw, fillister head, 0.25 inch by 0.5 inch... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16 || Screw, fillister head, 0.125 inch by 0.187 inch (ſº).... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17 | Screw, countersunk head, 0.125 inch by 0.187 inch (#3)..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18 Set Screw, hexagon head, 0.25 inch by 0.625 inch... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19 | Spring----------------------------------------------------------------------------------
20 | Spring plunger. . . . . . . ------------------------------------------------------------------
21 | Spring plunger cap.------------------------------. . . . . . . . . -----------------------------
HINIE GUNS.
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#
Ae
ANTIAIRCRAFT MATERIEL FOR MAC
54
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CHAPTER IV.
PEYCRU SIGHT, ANTIAIRCRAFT.
(Rear Area Antiaircraft Sight.)
(Plates 18, 20, 21, 22, 23, 24.)
A. THEORY.
The Peycru Sight is classed with the movable or rear-area sights.
It is fully as accurate as any machine-gun sight yet designed and is
also quite simple to manipulate. In designing it the 10 variable ele-
ments of antiaircraft fire mentioned in Chapter II were considered in
the same order of importance as listed.
First consideration was given to the speed of the aircraft because
of its variable nature.
The rated speed of aircraft may be expected to change from time
to time with future design, and the fact that the rated speed of an
aircraft is in relation to the surrounding air and not in relation to a
fixed point on the ground makes it apparent that an aircraft going
with the wind would travel faster than the rated speed in regard to
the gun position and less than the rated speed if going against the
wind. In view of these facts, seven airplane speeds were chosen,
varying by intervals of 25 kilometers per hour from 125 to 275 kilo-
meters per hour, both inclusive.
Beads representing these speeds are spaced on the sighting rod
to provide the maximum “lead " as calculated when the aircraft
flies directly across in front of the machine-gun position at 1,300
meters range. The range of 1,300 meters was judged to be the aver-
age range found under actual combat conditions.
The amount of “lead,” other than the maximum necessary to
score a hit on an aircraft, depends upon the direction of flight of
the aircraft. This is readily seen from the fact that no “lead"
at all would be necessary if the aircraft were approaching directly
toward the gun. In such a situation the increase of size is the only
indication of actual approach. Assuming that the aircraft travels
at a constant rate of speed in any horizontal direction, the proper
amount of “lead" is reached by keeping the sighting arm parallel
to the line of flight of the aircraft, as shown by the fact that when
the aircraft flies across the line of sight and requires the maximum
“lead " the same maximum condition is found to be shown on the
sight. In the same way any required fraction of this maximum
“lead '' is correctly shown on the sighting rod, when viewed from
the firing position, at the rear of the gun, by the same act of align-
56 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
ing the sighting rod in a position parallel to the flight of the air-
plane.
While it is not possible to use more than one average range in
calculating the position of the beads, it is possible to make use of an
additional approximate correction for range by using the beads fig-
ured for the higher speeds and utilizing the increased “lead 'so pro-
vided to counterbalance the greater ranges. The same correction
may be applied for the shorter ranges by using the slower speed
beads. This correction is used to take care of the effect of wind on
the airplane also.
Several of the factors mentioned in Chapter II have been found to
be within the accuracy of the sight, and so have been considered
constant or of zero value as the individual case required. These in-
clude cone of fire, jump of the gun, and drift of the bullet. The
velocity of the bullet is a known quantity for any one type of gun and
is rated as 2,700 feet per second at the muzzle of the American,
caliber .30, machine guns. The time of flight is taken from the
range tables of the United States Rifle, Model of 1903.
The two remaining features to be considered are the trajectory of
the bullet and the effect of high angle fire upon this trajectory
curve. The three horizontal wires, together with the top and bottom
of the front sight window, are calculated to give proper tangent
elevation corrections for horizontal fire at the ranges marked on
the sight. Having the front sight hang as a pendulum, automatically
reduces this maximum horizontal correction by the proper amount
as the angle of fire increases, until the correction reaches zero when
firing perpendicularly.
In general, it can be seen that those corrections applying to the
aircraft and its displacement during time of flight are corrected by
manipulating the rear sight, while the necessary changes due to the
vertical trajectory of the bullet are automatically cared for by the
front sight. Adjustments due to the difference in manufacture or
assembly of either the sights or the guns are made at the time of
assembly of each sight on its special gun, as described later in this
chapter.
B. GENERAL DESCRIPTION.
With the exception of the Hotchkiss Peycru sight, which has
been kept interchangeable with the French design, the front and
rear sights proper are, respectively, exactly alike for all American
machine guns and this general description will cover the sight for:
The Browning Machine Gun, Model of 1917.
The Vickers Machine Gun, Model of 1915.
The Marlin Tank Machine Gun, Model of 1918.
The Marlin Aircraft Machine Gun, Model of 1917.
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 57
The rear sight of the Peycru type is fastened to the various guns
by means of a suitable bracket, which differs to suit the conformation
of the particular make of gun.
The standard rear sight is permanently bolted to this bracket by
two standard bolts locked in place by lock washers. Each rear
sight bracket will be described separately under the heading of the
particular gun with which used. The sight proper consists of a
housing made with projection to bolt to the bracket as just mentioned
and a housing cap which, with the housing, forms a horizontal Sup-
port and a vertical bearing, allowing the remaining parts to revolve
360° in azimuth. Inside the housing and forming the bearing with
it, is the rod support which forms the upright frame and supports
the sighting rod and rod pivot at the top and the operating knob
at the bottom. The bearing of the rod pivot is horizontal, which,
in conjunction with the housing bearing, permits the sighting rod
to be pointed in any direction except the extreme top and bottom
position where the operating mechanism would lock. The sighting
rod is threaded to allow easy location of the sighting beads and also
to assemble the entire sighting rod onto the rod pivot by means of
two small nuts tightened against one another on either side of the
rod pivot. The beads on the sighting rod are held in place by body
bound threads and the enamel on the rod and beads. The operating
knob, which is hollow, is fastened to the rod support at its bottom
extremity by a riveted steel pin forming its horizontal axis. Another
steel pin through the ball, but, offset from the first, forms the con-
nection of the operating rod and transmits any vertical rotation of
the knob to the rod pivot above. A slot through the knob and the
rod support forms a passage for this operating rod inside of the
housing. Thus any rotation of the operating knob will produce a
corresponding movement of the sighting rod within the limits of the
definite stops provided to prevent the locking of the operating
mechanism.
The front sight also has a special type of attachment depending
upon the shape of the particular type of machine gun and each of
these will be described under the heading of the several guns for
which they are designed. However, the parts are identical with the
exception of the attaching parts just mentioned and the front sight
proper for the Hotchkiss Machine Gun, Model of 1914, which has
been kept interchangeable with the French Peycru design. The
front sight as a whole may be adjusted laterally by the slotted hole
in the front-sight support and vertically by changing the position of
the locking nuts on the stem of the fork. Inside the fork hangs
the front sight window frame, intersected by one central vertical
sighting wire, with three horizontal wires crossing it at various range
58 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
points. Attached to the front sight, but outside the fork, is a pen-
dulum to aid in stabilizing the front sight in vertical position when
the gun is moved upward for high-angle fire.
C. GENERAL DIRECTIONS FOR USE.
While the details of attachment vary with each type of machine
gun, the same method of alignment is used in each case. It is de-
sirable to follow the sequence of adjustments as listed below when
preparing a Peycru sight for actual fire.
1. Clamp the assembled rear sight and rear sight bracket tightly in
place. -
2. Establish the proper sight radius (25 inches on all guns but
the Hotchkiss, which is 29.43 inches), and clamp the front sight at-
tachment around the barrel or radiator of gun so that the vertical
sighting wire shall be vertical. -
3. Sight the gun by means of the regular sights on an objective
on the horizon and at one of the ranges specified on the front sight,
and hold the gun in this position. -
4. Turn the sighting arm down against the bottom stop and re-
volve it until the notch on the short end of the sighting rod can be
used as a sighting notch to make the lateral adjustment of the front
sight. The actual adjustment is made by loosening the lock nut on
the tap bolt holding the front sight support arm to the front sight
band just enough to allow the upper parts of the front sight to be
moved laterally into line between the rear sight and the object upon
which the gun is pointed. Tighten the tap bolt and then the lock nut
when in the proper lateral position. -
5. Raise or lower the front sight fork by loosening and tightening the
two nuts on the threaded portion at the bottom until the wire marked
with the same range as the distance from the gun to the aiming object
is in vertical alignment between the long notch on the side of the
rod pivot and the distant object.
NOTE.-The use of this notch is made possible by pointing the sighting arm
directly toward Or away from the eye of the person making the alignment.
A special wrench is furnished with each sight to be used when ad-
justing or mounting the sight. -
With the sight properly attached and adjusted at the correct sight
radius, the gunner determines the direction of wind and its approxi-
mate velocity, and is instructed about the nominal speed and range
of the aircraft target by the officer who directs the gunfire. The
sighting rod is placed parallel to the flight of the aircraft and the
gun sighted directly upon the aircraft, aiming across the bead on
the sighting rod, which suits the combined effect of nominal speed,
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 59
wind, and range, through the cross formed by intersection of the
vertical sighting wire with the horizontal wire which represents the
estimated range. As expertness in the use of this sight is acquired by
use and practice, the combining of these different factors becomes
an almost automatic mental operation, and the resultant fire much
more accurate. It is possible to use imaginary points between the
beads and imaginary ranges between horizontal wires of the front
sight when the operator becomes expert.
As the sights are of light construction and have no guards, care
should be used in handling them. The sighting rod On the rear sight
is particularly light to facilitate sighting, and special care must be
used so as not to bend or break it while the sight is attached to the
gun. The sight should be removed from the gun under transporta-
tion or during any extended time when the gun is not held ready for
immediate fire. The same care and attention should be given them to
preserve their accuracy and Serviceability as is given any other deli-
cate mechanism of the gun. They should be cleaned and oiled when-
ever necessary to prevent rust and wear. \ \
The horizontal flight of the combat type of airplane averages 200
kilometers per hour in still air, and the operator uses the red bead.
This is taken as the basis for the following rules for various condi-
tions of flight. The term “to increase one bead " means to use the
bead next farther out on the sighting rod beyond the red bead, and
such action would be caused by a greater speed due to assistance of
wind or gravity (aircraft descending) or because of greater range.
Inversely, “to decrease one bead " means to use the bead next nearer
the rod pivot, and this condition would be caused by the resistance
of wind or gravity (aircraft ascending) or because of a range short
enough for point-blank fire.
General correction, combat airplanes.
Ascending, decrease one bead to 175 kilometers per hour.
Descending, increase two beads to 250 kilometers per hour.
General correction, heavy, bombing type airplanes.
Ascending, decrease two beads to 150 kilometers per hour.
Descending, increase one bead to 225 kilometers per hour.
Horizontal, decrease one bead to 175 kilometers per hour.
Range correction (Hotchkiss gun):
1,000 to 1,400 meters, increase one bead.
1,400 to 1,700 meters, increase two beads.
1,700 to 2,000 meters, increase two beads.
Range correction (American guns):
1,300 to 1,500 meters, increase one bead.
1,500 to 1,600 meters, increase two beads.
{ 0 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNs.
S
73. 2. -
rº -
;
§
§:
A6/7//yS7 Vy//YP W/7// Vy/A/O 2/460/vaa-cy aca/awsr aſa GoavaLLy w/7//
ſ/V/AWO W/AWD
PLATE 19.
Wºnd correction for 24 kilometers (approximately 15 miles) per
hour or 48 kilometers (approximately 30 miles) per hour.
Wind velocities:
Direction. 24 kiloS § miles),
48 kilos (30 miles).
- Beads. Beads.
Against Wind-------...................................................... decrease. . 1 2
With wind........ . . . . . . . . . . . . -------------- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - increase . . 1 2
Diagonally against........................................... . . . . . . . . . . . . . decrease. . . . . . . . . . . . . 1
Diagonally With----------............................. . . . . . . . . . . . . . . . . . . . . increase...} 1 2
It is not practical to expect effective fire with .30-caliber machine
guns at more than 1,300 meters, due to great reduction of velocity
at the greater ranges. - •
As Soon as the line of sight is on the aircraft open fire, if the order
has been given. Fire in bursts of as long duration as practicable,
holding the gun solidly fixed during the burst.
The number of bursts should be as great as possible. Between
bursts, readjust the sighting rod into a parallel position with the
aircraft and increase or decrease the line of sight from bead to
bead as the changing conditions require.
SIGHT, ANTIAIRCRAFT, PEYCRU, FOR HOTCHKISS MACHINE GUN, MODEL OF 1914.
(Rear Area Antiaircraft Sight.) -
- (Plate 20.)
The Peycru sight for the Hotchkiss machine gun has been kept
interchangeable with the French design for that gun in any com-
bination where the sight as a whole is concerned. This sight, which
is mounted upon the gun by attaching it to the shoulder stock, may
be used in both its American and French form upon either the Ameri-
can or French stock for the Hotchkiss gun.
1. Directions for attaching.—Assemble the sight upon the shoulder
stock and then mount the stock upon the gun, as described in Chap-
ter VII, page 137. .

61
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ANTIAIRCRAFT MATERIEL FOR MACHINE
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62 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
In assembling the rear sight to the stock be sure that the machined
shoulders on the housing seat properly with the machined surfaces
on the bracket. The front sight is attached as a unit, to the forward
part of the barrel, at a distance of 29.43 inches from the rear sight,
with the sight on the left-hand side of barrel; aligning adjustments
being then made as previously indicated in this chapter.
2. To dismount.—Reverse the assembling operations.
3. For directions as to the method of using the sight, refer to
Part C of this chapter, “General directions for use.”
List of parts, Sight, Antiaircraft, Peycru (29.43 sight radius), for Hotchlciss
Machine Gun, Model of 1914.
(Rear Area Antiaircraft Sight.)
Number
Name of part. required
N
O.
------
Bolt.----------------------------------------------------------------------------------.
Bolts, 0.125 by 0.5 inch -------------------------..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bolts, tap, 0.375 by 1.5 inches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ---.
Bolts, 0.312 (*) by 1 inch thread, by 0.75 inch long. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Eccentric pin---------------------------------------------........ . . . . . . . . . . . . . . . . . . . . .
Front sight-----------------------------------------------........---------------------
12 Nuts, 0.312inch (*).------------............................................ * = s = * * * * * * * *
13 | Nuts, 0.125 inch........................................................................
14 || Nuts, 0.190 inch by 0.156 (#) thick.......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15 || Nuts, hexagonal, 0.25–28 per inch, U. S. standard thread. . . . . . . . . . . . . p = • - - - - - - - - - - - - - - -
16 Operating knob................................. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
17 | Operating rod--------------------................................. . . . . . . . . . . . . . . . . . . . . .
18 Pendulum. -----------------------------------.................. . . . . . . . . . . . . . . . . . . . . . . .
19 || Pins, Steel, 0.08 by 0.625 inch... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20 Pins, steel, 0.093 § by 0.375 inch-----------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21 || Pins, steel, 0.187 (ºs) by 2 inches... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ‘. . .
22 || Pins, Split, 0.046 (#) by 0.5 inches... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23 Rod, pivot-----------------------------------............... . . . . . . . . . . . . . . . . . . . . . . . . . . .
24 || Rod Support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - - - - -
25 | Screw, round head, 0.125 by 0.312 inch (*). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26 Sight fork--------------------------. . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
27 | Sight fork Cap-- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
28 || Sighting rod, No. 49 (0.073 inch T. D. and S. W. gage) or equal. . . . . . . . . . . . . . . . . . . . . . . . .
29 | Sighting rod bead---------------------------------------------------------------------.
30 | Sighting rod nut. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31 | Sighting rod tube. ------------------------------....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
32 asher, lock, 0.125 inch------------------------...-------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
33 wire, No. 20, 6.034 (W. and M. gage) by 2.375 inches..................................
34 || Wire, No. 20, 0.034 (W. and M. gage) by 1.125 inches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
35 | Washers, 0.25 inch. ------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
36 | Washers, 0.312 inch (ºr). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
37 | Washers, 0.190 by 0.031 (ºx) inch thick. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
38 Wrench-------------------------------------------------------. . . . . . . . . . . . . . . . . . . . . . . . .
SIGHT, ANTIAIRCRAFT, PEYCRU, FOR BROWNING MACHINE GUN, MODEL OF 1917.
(Rear Area Antiaircraft Siſ/ht.)
(Plates 21, 18.)
1. Directions for attaching.—The rear sight will be furnished
assembled to the rear sight bracket. When the end of the inverted
U-shaped bracket has been inserted into the triangular opening
of the panoramic sight bracket on the left-hand side of the gun
as far as the stop will permit, the rear sight will be in the correct
position. Clamp the thumb screw until the sight is held in place
without rattle. The front sight band is tightened slightly on the
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
152535—20—5


64 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
radiator so that the sight is on the left and the clamp on the right.
Follow the detailed directions already given for adjusting the front
sight.
2. To dismount.—Reverse the assembling operation.
3. For directions as to the method of using the sight, refer to
Part C of this chapter, “General directions for use.”
List of parts, Sight, Antiaircraft, Peyoru (25-inch sight radius), for Browning
- Machine Gun, Model of 1917.
(Rear Area Antiaircraft Sight.)

Number
required.
N
O.
Name of part.
Bolts, 0.25 by 0.75 inch-----------------------------------------------------------------
Bolt, tap, 0.312 (*) by 1 inch, thread 0.75 inch long....................................
Clamping screw-----------------------------------------------------------------------.
Clamping screw handle-----------------------------------------------------------------
Eccentric pin........... • * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Front sight-----------------------------------------------------------------------------
Front sight band § e as gº º is as º ºs s as º is s as º is e º ºs e g º ºs e º e º sº º e s ∈ e º º ºs e º ºs e s = sº g º ºs º ºs º e g º ºs ºº e º e º is tº e = *
Front sight band (upper)--------------------------------------------------------------
Front sight bracket--------------------------------------------------------------------
15 Nuts, §§y 0.156 inch (#) thick----------------------------------------------------.
16 Nuts, 0.25 inch------------------------------- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
17 | Nuts, 0.312inch (#)--------------------------------------------------------------------
18 Nuts, 0.312 inch Gºs)---------------------------------------------------- \e ºn as e s = e s e º s • * * *
19| Operating knob------------------------------------------------------------------------
20 | Operating rod--------------------------------------------------------------------------
Pendul
6I1OlùlúIII
22 | Pins, Split, 0.046 (*) by 0.5 inch--------------------------------------------------------
23 || Pins, steel, 0.08 by 0.625 inch-----------------------------------------------------------
24 || Pins, 0.093 § by 0.375 inch-----------------------------------------------------------
25 | Pins, 0.187 (Ps) by 2inches-------------------------------------------------------------
26 | Rear sight bracket--------------------------------------------------------------------.
27 | Rod pivot------------------------------------------------------------------------------
28 || Rod Support--------------------------------------------------------------------------.
29 Screws, round head, steel, 0.125 by 0.375 inch...........................................
30 Screws, 0.125 by 0.312 inch (#)--------------------------------------------- '- - - - - - - - - - - -
31 Sight fork------------------------------------------------------------------------------
32 | Sight fork cap-------------------------------------------------------------------------.
33 | Sighting rod.---------------------------------------------------------------------------
34 || Sighting rod bead----------------------------------------------------------------------
35 | Sighting rod nut-----------------------------------------------------------------------
36 | Sighting rod tube----------------------------------------------------------------------
37 ashers, 0.190 inch by 0.031 inch (ºr) thick ...........................................
38 || Washers, 9.342 ingh (*)---------------------------------------------------------------.
39 Washers, lock, 0.125 inch--------------------------------------------------------------.
40 Washers, 0.25 inch...I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.I.
41 || Wire, No. 20, 0.034 % & M. }
42 Wire, No. 20, 0.034
43 Wrench--------------------------------------------------------------------------------
SIGHT, ANTIAIRCRAFT, PEYCRU, FOR VICKERS MACHINE GUN, MODEL OF 1915.
(Rear Area Antiaircraft Sight.)
(Plate 22.) *
1. Directions for attaching.—The rear sight will be furnished
assembled to the rear sight bracket. To mount it, first unscrew and
remove the upper cap of the left handle grip of the Wickers ma-
chine gun; then set the sight bracket in position, with its circular
aperture over the handle grip top and its lugs straddling the upper
and lower left arms of the handle grip; then replace the screw cap
on the handle grip through the bracket aperture and screw down
L– 2xaca sºr exots
PLATE, 22.-Peycru Sight, Antiaircraft, for Wickers Machine Gun,
(Rear Area Antiaircraft Sight.)
Q
Model of 1915.
Z2°.
#/CAAA’s
/4/5.
\
§

66
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
the cap until the rear sight is rigidly clamped in position, as shown
in illustration.
The front sight band is placed on the water jacket, of the machine
gun, with the sight on the left side and the clamping screw on the
right, at a distance of 25 inches from the rear sight. The sight band
is then adjusted around the radiator until the front sight is vertical;
then clamped in position by turning the clamping Screw.
2.
To dismount.—Reverse the assembling operation.
3. For directions as to the method of using the sight, see Part C
of this chapter, “General directions for use.”
List of parts, Sight, Antiaircraft, Peycru (25-inch sight radius), for Vic/cers
Machine Gun, Model of 1915.
(Rear Area Antiaircraft Sight.)
Name of part.
--~~~~~ *-****
Number
required.
Bolts, 0.25 inch by 0.75 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bolts, tap, 0.312 inch (ſº) by 1 inch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ClampingScrew---------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clamping screw handle... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Eccentric pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight.------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight band § as s s sº * * * * * s e º ºs s is e º sº s s sº tº e s is sº e s s = * * * * * * s is s e e s is a sº a s = s is s sº e º s is e s s a s s sº
Front sight band (upper)... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front sight bracket---------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Sight Support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Handle collar. -------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Housing--------------------------------------------------------------------------------
Housing Cap---------------------------------------------------------------------------
Hinge pin----------------------------------------- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nuts, 0.190 inch by 0.156 inch (3%) thick. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nuts, 0.25 inch--------------------------------------- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Nuts, 0.312 inch (*)--------------------------------------------------------------------
Nuts, 0.312 inch (ºs).---------------------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating knob------------------------------------------------------------------------
Qperating rod-:----…-----------------------------------------------------------------
Pins, 0.08 inch by 0.625 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pins, 0.093 inch #} by 0.375 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pins, 0.187 inch (ºs) by 2 inches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , - - - - - - - - - - - - - - - - - -
Pins, split, 0.046 inch (#) by 0.5 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pendulum - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Rear sight bracket. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rod pivot.------------------------------------------- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Rod Support --------------------------- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Screws, round?lead, 0.125 inch by 0.312 inch (#). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Screws, round head, 0.125 inch by 0.375 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sight fork----------------------------------------- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Sight fork Cap- - - - - - - - - - - - - - - - - - - -,-,-,-,-,- - - - - - - - -3.- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Sighting rod, No. 49 (0.073 inch), T. D. and S. W. gage... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sighting rod bead. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ------------------------------.
Sighting rod nut-------------------------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . .
; rod tube, No. 17, B. & S., gage.-:-----------------. . . . . . . . . . . . . . . . . . . . . . . . . .--
ashers, 0.190 inch by 0.031 inch (ºr) thick. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Washers, 0.312 inch (*). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Washers, lock, 0.25 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Washers, lock, 0.125 inch----------------------------------------. . . . . . . . . . . . . . . . . . . . . . .
Wire, No. 20, 0.034 inch (W. & M. gage) by 2.25
Wire, No. 20, 0.034 inch (W. & M. gage) b
Wrench. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ------------------- - - - - - - - - - - - - - - - - - - - - - - - - - -
& as ºs as * * * is s is ºf s is s a s is is sº s is as s is sº s gº º is sº is sº a s
y
12
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3
SIGHT, ANTIAIRCRAFT, PEYCRU, FOR MARLIN TANK MACHINE GUN, MODEL OF 1918.
(IRear Area Antiaircraft Sight.)
/
(Plate 23.)
1. Directions for attaching.—The rear sight will be furnished
assembled to the rear sight bracket. To mount the Peycru sight, re-
move the two fillister head screws holding the rear sight fixed base on
67
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.ANTIAIRCRAFT MATERIEL FOR MACHINE GUNS.
(‘¿q0ļS Q / 0.10.ųoņtt ſº 100.ł F -- D03I)
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*


68
&
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
the gun. Replace them by the two studs furnished with the sight,
tightening them well.
Place the bracket over the studs and tighten
the nuts against the lock washers and bracket tightly enough to hold
the sight in place firmly. The front sight band is slipped over the
end of the radiator after removing the regular tank front sight. Re-
place the sight just removed. Follow the detailed directions already
given for adjusting the front sight.
2.
To dismount.—Reverse the assembling operations.
3. For directions as to the method of using the sight, see Part C of
this chapter, “General directions for use.”
List of parts, Sight, Antiaircraft, Peycru (25-inch 8ight radius), for Marlin Tank
Machine Gun, Model of 1918.
(Rear Area Antiaircraft Sight.)

N
O.
Name of part.
Number
required.
Wire, 0.034 inch
Attaching screw-----------------------------------------------------------------------.
Bolts, 0.25 inch by 0.75 inch------------------------------------------------------------
Bolts, tap, 0.312 inch (#) by 1inch--------------------------------.................'- - - -
Eccentric pin-------------------------------------------------------------------------.
Front sight----------------------------------------------------------------------------.
Front Sight band-----------------------------------------------------------------------
Front sight brace ----------------------------------------------------------------------
Front Sight bracket--------------------------------------------------------------------
Front sight support--------------------------------------------------------------------
Housing--------------------------------------------------------------------------------
Housing cap. --------------------------------------------------------------------------
Nuts, 0.190 inch by 0.156 inch (#) thick... . . . . . . . . . . . . . . . . . . . ..........................
Nuts, 0.25 inch-------------------------------------------------------------------------
Nuts, 0.312 inch (#)------------------------------------------------------- - - - - - - - - - - - - -
Nuts, 0.312 (#)-------------------------------------------------------------------------
Nuts, 0.375 inch------------------------------------------------------------------------
Operating knob------------------------------------------------------------------------
Operating rod. . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Pendulum-----------------------------------------------------------------------------
Pins, 0.08 inch by 0.625 inch------------------------------------------------------------
Pins, 0.093 inch #} by 0.375 inch------------------------------------------------------
Pins, 0.187 ingh (ºs) by 2inches:-----------------------------------------------------.
Pins, Split, 0.046 inch (ºr) by 0.5 inch------------------------------------------------...
Rear sight bracket---------------------------------------------------------------------
Rivets, 0.126 inch by 0.625 inch---------------------------------------------------------
Rivets, countersunk, 0.125 inch by 0.562inch (#). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rod pivot.-----------------------------------------------------------------------------
Rod support---------------------------------------------------------------------------
Screws, round head, 0.125 inch by 0.312 inch (#). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Screws, round head, 0.125 inch § 0.375 inch-------------------------------------------.
Screws, Set (Cup point), 0.312 inch (#2) by 1 inch - - - - - . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sight fork------------------------------------------------------------------------------
Sight fork cap..... - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Sighting rod, 0.073 inch (No. 49, T. D. and S. W. gage)... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sighting rod bead---------------------------------------------------------------------.
Sighting rod nut---------------------- • - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
ś rod tube----------------------------------------------------------------------
ashers, 0.190 inch by 0.031 inch (#2) thick. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Washers, 0.312 ingh (#)-------------------------------------------------------------...
Washers, lock, 0.125 inch. . . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Washers, 0.25 inch---------------------------------------------------------------------
Washers. 0.375 inch--------------------------------------------------------------------
Wire, 0.034 inch §§ 20, W. & M. § by 2.25 inches------------------------------....
No. 20, W. & M. gage) by 1.125 inches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
|
SIGHT, ANTIAIRCRAFT, PEYCRU, FOR MARLIN AIRCRAFT MACHINE GUN, MoDEL
1.
OF 1917.
(Rear Area Antiaircraft Sight.)
(Plate 24.)
Directions for attaching.—The rear sight will be furnished
assembled to the rear sight bracket. To mount the Peycru sight, re-
remove the two fillister head screws holding the front end of the lock
69
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ANTIAIRCRAFT MATÉRIEL FOR MACEIINE GUNS.
('\\\^\$ 410.404$wguy poły wpo?!)
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70
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNs.
container. These screws will be replaced by special attaching screws
inserted into the same holes, while holding the rear sight bracket
in place. The front sight bracket is slipped over the end of the
barrel so that the sight is on the left-hand side and the clamping bolt
on the right. Follow the detailed direction already given for adjust-
ing the front sight.
2.
To dismount.—Reverse the assembling operations.
3. For directions as to the method of using the sight, refer to
Part C of this chapter, “General directions for use.” *
Aircraft Machine Gun, Model of 1917.
(Rear Area Antiaircraft Sight.)
- List of parts, Sight, Antiaircraft, Peycru (25-inch Sight radius), for Marlin

Name of part.
Number
required.
Attaching screw.---------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..............
Bolts, 0.25 inch by 0.75 inch................................ -------------...............
Bolts, tap, 0.25 inch by 0.75 inch. ------------------------------.... . . . . . . . . . . . . . . . . . . . .
Bolts, 0.312 inch (ºs) by 1inch ---------------------------------------------.... . . . . . . . .
Eccentric pin. -----------------------------. * * * * * * * is s º ºs s sº as sº as s is 4s is sº is e s s as sº is sº e s is as e s a s & as s s s &
Front sight.---------------------------------------------------------------------------.
Front sight bracket -------------------------------------------------------------.......
Front Sight support -------------------------------------------------------------------.
Housing-------------------------------------------------------------------------------.
Housing cap--------------------------------------------------------------------------.
Nuts, 0.190 inch by 0.156 inch (#2) thick . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nuts, 0.25 inch------------------------------------------------------------------.......
Nuts, 0.312 inch (*).------------------------------------------------------------------.
Nuts, 0.312 inch (*)-------------------------------------------------------------------.
Nuts, 0.375 inch-----------------------------------------------------------------------.
Operating knob-----------------------------------------------------------------------.
Operating rod.------------------------------------------------------------------------.
Pendulum -----------------------. . . . . . . . . . . . . . . . *- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Pins, 0.08 inch by 0.625 inch... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * - - - -
Pins, 0.093 inch § by 0.375 inch -----------------------------------------------------
Pins, 0.187 inch (Ps) by 2inches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pins, Split,0.046 inch (*) by 0.5 inch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Sight bracket . . . . . . . . . . . . . . . . . . .-----------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rod pivot.----------------------------------------------------------------------------.
Rod Support --------------------------------------------------------------------------.
Screws, round head, 0.125 inch by 0.312 inch (3%). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Screws, round head, 0.125 inch by 0.375 inch...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sight fork-------------------------------------------------------------------. . . . . . . . . . .
Sight fork cap-----------------------------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . .
Sighting rod, 0.073 inch (No. 49, T. D. & S. W. gage). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sighting rod bead.------------------------------------- as as tº e s is as sº e º ºs e s is a me • * * * * * * * * * * * * * * *
Sighting rod nut-------------------------------------------------------------..........
Sighting rod tube------------------------------------------------------------. . . . . . . . . .
Washers, 0.190 inch by 0.031 inch (#1) thick. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Washers, 0.312 inch (*)-----------------------------------------------. . . . . . . . . . . . . . . . .
Washers, lock, 0.125 inch.-------------------------------------------------------------.
Washers, lock, 0.25 inch------------------------------------------------------------....
Washers, lock, 0.25 inch---------------------------------------------------------------.
Washers, 0.375 inch -------------------------------------------------------------------.
Wire, 0.034 inch §§ 20, W. & M. §
Wire, 0.034 inch (No. 20, W. & M. gage) by 1.125 inches... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wrench-----------------------------------------------------------------------. . . . . . . . .
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S
CHAPTER V.
STADIA.
(Plates 25, 26, 27.)
DESCRIPTION.
The stadia is a very simple device used to estimate the approximate
distance of an aircraft. It consists of a small metal plate having
openings of determined size through which the aircraft is viewed
while the plate is held at a fixed distance from the eye, indicated
by a string attached to the plate, the outer end of the string being
held against the face of the observer.
There are two types of stadia: (a) The British “range indicator,”
which is an oval, flat metal disk with a handle extension, having four
round viewing apertures in its upper section, for viewing light or
heavy type planes, seen sidewise or end-on; (b) the Peycru stadia,
of French design, herewith described and illustrated, which is con-
sidered the best and is the official type.
The Stadia, Peycru, is an oblong, flat, black-enameled metal plate,
about ſº inch thick, 5% inches long, and 1% inches wide, shaped out-
wardly like two lyres joined at the base, as indicated by its French
name of “ lyre telemetre,” and having a deep V opening in each end,
with white lined inner lugs and adjoining range scale marking the
various sighting points. The V openings differ in size; the narrower
one being for use on the smaller, combat, type of aircraft, and the
larger one for heavy aircraft of the bombing type. Aircraft seen
sidewise are viewed as bridging across corresponding lugs; aircraft
seen end-on as bridging between walls of the V in the recesses be-
tween lugs. A cord, 22.83 inches (58 centimeters) in length, runs
loosely through a hole in the center of the stadia, held there by a
button enlooped in each end.
The range scale on this stadia is marked in meters. As a meter is
39.39 inches and a yard 36 inches, and aircraft range finding is neces-
sarily only approximate, yards and meters in antiaircraft work may
be considered as interchangeable units of measurement.
Knowledge of the general dimensions of the various types of air-
craft and ability to recognize them are of essential importance in
the effective use of the stadia range indicator, and it is advisable
that constant training in this regard be carried on. -
71
72 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNs.
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Stadia, Peycru, complete.
FIG. A. FIG. B.
Length view. Width View.
How aircraft should appear in Stadia.
PLATE 25.-Stadia. (Range Indicator.).
Raºuſſé graduation 48 ºn meters.


ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 73
THEORY OF USE OF THE STADIA.
(Plate 26.)
Assume the point E as the eye, and points A–B as two opposite
points on corresponding lugs or notches in V opening of stadia, and
D—G. as the length or width of an aircraft. The line E–G is at
right angle to the line A–B and is the fixed distance from the eye to
the stadia, representing the string when held taut.
Then, since A B and D G are known and fixed, and the angle
A E 0 is the same as the angle D E F and fixed, and the length of
line E C known and fixed, the length of the range line E F is fixed
and may be calculated, as has been done for the various sighting
points marked on the stadia. The range graduations on the stadia
(in meters) are based on the following assumed dimensions of air-
craft viewed: -
Combat type: Side view, 7 meters; end view, 9 meters. *
Bombing type: Side view, 8 meters; end view, 124 meters.
D
_--- ~T
A_____--~~~~ |
_-T |
E. C |F
T- t
T----- |
B T-----_ ~!
G
PLATE 26.—Diagram illustrating theory of the stadia.
DIRECTIONS FOR USE OF STADIA.
(Plates 25, 27.)
(a) Identify the aircraft viewed, type and dimensions.
(b) Decide which end V opening of the stadia suits the type of the
aircraft, “combat” or “bombing.” -
(c) Grasp the stadia by its lower part in one hand with proper
opening uppermost and graduated side faced. Loosen the string
with the other hand and press the beaded tip of it against the chin.
Extend the hand holding the stadia until the spring is taut. Close
one eye. Hold stadia between the eye and the aircraft and move
it about until the aircraft appears as bridging across the V opening
with its Outermost edges just touching the opposite sides of same.
If the aircraft is seen in profile it should appear as bridging across
corresponding lugs, nose touching one and tail the other (fig. A.,
pl. 25); if seen end-on it should be framed in a notch or recess be-
tween lugs, wing tips touching the opposite walls of the V (fig. B,
pl. 25). Note the range indicated by the range scale at the point
where the correct appearance of the aircraft occurs, and instantly
74
PLATE 27.
-
AM OFFICER US ING THE STADIA RANGE INDICATOR.

ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 75
inform the gunner, Hold the stadia always with the aircraft
straight across the V, as in Plate 25.
REMARKS.—The gun commander should estimate the range and
advise the gunner. Every member of the gun crew should, however,
be qualified in the use of the stadia. In forward area or trench
fighting (in which the fixed Trench Sight is usually employed) the
stadia range indicator is not as important a factor as it is in con-
nection with the adjustable sights used in rear areas, for the reason
that the range of the low flying aircraft that attack forward areas
can be judged to large extent without apparatus. Primarily the
stadia, which necessarily must be rapidly used, indicates whether or
not the enemy aircraft is within range. If the outer edges of an
aircraft of approximately known size touch the sides of the correct
aperture at an indicated range of 1,250 meters or less, it is close
enough to shoot at with machine guns—the gunner using his judg-
ment and tracer bullets to get the exact range. Stadia observations
should always be as precisely correct as possible, to Save time and
ammunition. -
When not in use the stadia is carried in the gun sight case.
PLATE 28.
ANTIAIRCRAFT MACHINE GUN MOUNT IMPROVISED BY A. E. F., BELGIUM.
SHOWS LEWIS GUN WITH RAD IATOR CLAMP BAND AND TUBE OF BRITISH
LIGHT FOLDING STAND MOUNTED ON A SPIKE IN TOP OF POST.

76
CHAPTER VI.
ANTIAIRCRAFT MACHINE GUN MOUNTS.
GENERAL INTRODUCTION.
In order that a machine gun may be fired effectively against air-
craft at all altitudes and all angles of approach, the gunner must
be able to maneuver the gun freely in the horizontal and vertical
planes. The ordinary machine gun tripods will not permit of high
angle fire, and it is therefore necessary to provide special means of
mounting machine guns for defense against aircraft.
In the earliest stages of the development of antiaircraft gunnery,
improvised mounts were made in the field with any means at hand.
As an example of this, a cart wheel was often fastened to the top
of a post, so that it would swing horizontally about a central pintle
or axle, and the machine gun was attached to the rim of the wheel.
The gunner would then walk around the post pushing the machine
gun, and was thus able to point the gun, while supported on the rim
of the wheel, in any desired direction. This method was crude, but
effective. In the case of belt-fed guns, it is necessary to guide the
belt into the gun when firing at high angles to insure satisfactory
feeding. This is done by attaching the ammunition box to the
adapter or cradle carrying the gun in Such a manner that the box
will be moved with the gun in all positions. A belt guide, consisting
of a metal clip cover for the ammunition box, is also desirable for
high angle fire to prevent the ammunition belt from falling out of the
box and to guide the belt into the gun.
TYPES.
As the antiaircraft defense roughly divides itself into two divi-
sions, namely, forward area defense and rear area defense, the types
of mounts can also be so classified.
Mounts for forward area work should be as light as consistent with
any certain design and extremely mobile.
Mounts for the defense of rear areas are generally more or less
fixed in position, and can be of a heavier and less mobile type.
Each type of army organization provided with antiaircraft ma-
chine guns offers particular problems as to the type of mount best
suited for its use, and the transportation of material.
Various organizations, among them field artillery batteries, rail-
way batteries, antiaircraft machine gun batteries, infantry machine
77
78 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
gun companies, and organizations detailed for the defense of dumps,
etc., must be provided with suitable antiaircraft machine gun mounts.
To meet the various requirements, the following types of antiair-
craft machine-gun mounts have been developed:
(1) Antiaircraft Machine Gun Mount, Cygnet type, with Trailer
and Ammunition Trailer. -
(2) Antiaircraft Adapter for Machine Gun Tripod, Model of
1917 (Browning), and Machine Gun Tripod, Model of 1918 (Cygnet).
(3) Antiaircraft Improvised Post Mount. -
(4) Antiaircraft Machine Gun Tripod, Model of 1918.
(5) Antiaircraft Machine Gun Trailer, Sechler type.
(6) Antiaircraft Machine Gun Light Folding Tripod.
TREND OF DESIGN.
The trend in design of antiaircraft machine-gun mounts, at this
time, is toward extreme simplicity. About all that is required
is a suitable support which will allow the gun to be swung freely
through 360° in a horizontal plane and elevated freely from approxi-
mately 15° below to 90° above horizontal, with suitable means for
moving the ammunition box with the gun in the case of belt-fed guns.
The guns should be maneuvered by hand and no elevating or tra-
versing gears, hand wheels, or cranks are necessary. No means for
accurately laying the gun are necessary. .
WARNING.
In the use of all antiaircraft machine gun mounts it should be
remembered that if the gun is released, that is, not supported by the
shoulder or hands of the gunner, it will fall to and hang in a vertical
position, pointing upward, as it is free to move and not restrained
or held in position save by the gunner.
Each of these mounts will be described under a separate heading
in the following pages.
ANTIAIRCRAFT ADAPTER FOR MACHINE GUN TRIPOD, MODEL
OF 1917, AND MACHINE GUN TRIPOD, MODEL OF 1918.
(Plates 29, 30, 31, 32, 33.)
1. Description.—The machine gun tripods issued for regular ma-
chine-gun service are not designed to permit of Sufficient elevation
for the high-angle fire necessary against aircraft. In order to utilize
these tripods for antiaircraft work an attachment is required that
will allow of overhead shooting.
The Antiaircraft Adapter for Machine Gun Tripods is designed
for this purpose. It is made for the Machine Gun Tripod, Model
of 1917 (Browning tripod), and Machine Gun Tripod, Model of 1918
(Cygnet tripod). It takes the Browning or Vickers gun.
PLATE 29.
ANTIAIRCRAFT ADAPTER For MacHINE GUN TRIPOD, MODEL OF 1917 (BROWN-
ING), AND MACHINE GUN TRIPOD, MODEL OF 1918 (CYGNET), WITH SIDE
PLATES SET For MoUNTING on LATTER. THE VICKERS AMMUNITION
Box contal NER or ATTAcHING BASKET IS SHOWN AT RIGHT SIDE.
152535–20–6 79


80 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GTUNS.
The adapter consists of a bracket height-extension piece, the lower
end of which bears side plates, detachable and invertible, which rest
on and are fitted to the contour of the head of the tripod gun cradle,
the flange sides of the bracket fitting within the cradle head. A
transverse pin, taking the place of the gun-pivoting pin, passed
through the cradle head and bracket flanges, fastens the adapter
bracket rigidly on the tripod. The upper end of the bracket, or
height-extension piece, receives the adapter proper, or gun holder,
which is attached to the bracket by a pin through coinciding holes in
bracket and adapter. The machine gun is mounted on the adapter
just as it is mounted on the gun cradle of the tripod; that is, with
pins through the forward and rear holes provided in the adapter,
passing through the coinciding attaching holes on the under side of
the gun. -
The adapter has on its left side a clip to receive a Browning Am-
munition Box, and on its right side a clip to receive a metal Container,
or basket, for the Vickers Ammunition Box, which is provided with
no clip slots, or grooves, in its sides to permit direct attachment to the
adapter. .* º .
The adapter pieces or side plates which fit the upper contour of the
tripod-gun cradle and hold the adapter bracket rigid are mounted on
threaded bolt ends which project on the opposite sides of the bracket,
held in place by crown nuts screwed against the plates. One edge of
these plates is made to fit the contour of the Browning tripod head,
the other edge to fit the contour of the Cygnet tripod head. Either
edge is turned downward as required by removing the nuts, inverting
the plates, and Screwing nuts on again. These plates are designed to
provide for filing to fit the tripod head. This filing fit is made neces-
sary by the fact that the tripod heads are not machined to a uniform
tolerance and some variation results.
2. Directions for attaching.—Remove the forward and rear gun
mounting pins from the tripod gun cradle. Place the adapter
bracket, with the proper edges of the side plates downward, with its
lower end flanges within the tripod cradle, flange holes registering
with gun pivot pin holes in the cradle and side plate edges fitting
the cradle head contour. Insert and lock the attaching pin. It may
be necessary to file the edges of the side plates to fit the head contour
of the tripod used. If so, file carefully and not more than necessary,
because the fit should be just right to insure the rigid attachment of
the bracket. g
In mounting the adapter remember that it should incline slightly
toward the antiaircraft gunner, the gun when mounted overhanging
the tripod, in reversed position to its usual Service mounting for low-
angle firing. It is thus possible to get vertical elevation of the gun
if required.
PLATE 30.
ANTIAIRCRAFT ADAPTER FOR MACHINE GUN TRIPODS MOUNTED ON MACHINE
GUN TRIPOD, MODEL OF 1917 (BROWN ING TRIPOD).
S1.

PLATE 31.
---
… º -- º …
ANTIAIRCRAFT ADAPTER FOR MACHINE GUM TRIPODS AS USED ON MACHINE
GUN TRIPOD, MODEL OF 1917, WITH BROWNING MACHINE GUN, MODEL OF
1917, TRENCH SIGHT, EXPENDABLE AMMUNITION BOX AND CARTRIDGE BELT
GUIDE.

82 -
PLATE 32.
ANTIA RoRAFT ADAPTER FOR MACHINE GUN TRIPODS, MOUNTED ON
MACHINE GUN TRIPOD, MODEL OF 1918 (CYGNET TRIPOD).
83



PLATE 33.
º º º
º
… º * .
ANTIAIRCRAFT ADAPTER FOR MACHINE GUN TRIPODS AS USED ON MACHINE
GUN TRIPOD, MODEL OF 1918 (CYGNET), WITH BROWN ING MACHINE GUN,
MoDEL of 1917, TRENCH SIGHT, EXPENDABLE AMMUNITION BOX AND
CARTRIDGE BELT GUIDE.
84

ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 85
Attach the ammunition box by means of the proper clip to side
of adapter; place Cartridge Belt Guide on the ammunition box, and
See that all pins and clamps are tight. The gun, if allowed to hang,
Will now point vertically upward and can be swung and elevated
at Will by hand. It is ready for use.
3. Method of use.—The adapter and gun having been properly
mounted, the ammunition box attached, opened, cartridge belt fed
into the gun and cartridge belt guide placed on ammunition box,
the gunner seats himself on the ground or lies under the gun in
Some convenient position, depending on the angle of fire. It will
probably be necessary for the gunner to place his legs between the
legs of the tripod, which will handicap him in traversing the gun,
especially if the tripod stands on a level surface.
The machine-gun tripod when used with the gun mounted higher
than usual and in reversed position, as necessary in this antiair-
craft work, will probably not be stable at all angles of fire. The
gunner, therefore, must adjust and place the tripod legs to best
advantage and make such provisions for weighting down the tripod
as may seem necessary. It must be remembered that this adapter is
an improvised attachment to accomplish easily and quickly the best
results obtainable under the conditions. It is not an ideal device,
but more in the nature of an emergency mount. .
It is possible to dig a pit and spread the legs of the tripod out
horizontally, placing them on the edges of the pit and operating the
gun from below.
List of parts of Antiaircraft Adapter for Machine Gun Tripod, Model of 1917
(Browning), and Machine Gum Tripod, Model of 1918 (Cygnet).
Number
Name of part. required.
N
O
*-
Adapter piece Spacer-------------------------------------------------------------------
Adapter trunnion pin -----------------------------------------------------------------.
Adapter trunnion pin Stud------------------------------------------------------------.
Adapter piece (right)-------------------------------------------------------------------
Adapter piece (left) --------------------------------- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Ammunition box bracket side piece (left). -----------------------------. . . . . . . . . . . . . . . .
Ammunition box bracket Side piece (right).... . . . . . . . . . . . . . . . . . . . * = • * * * * * * * * * * * * * * * * * * = =
Ammunition boxclip------------------------------------------------------------------
Ammunition box container (Vickers) -----------------------------------..... . . . . . . . . . .
10 || Ammunition box support § * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * s = e º ºs & sº * * * * * = as as sº sº a
11 || Ammunition box support (right).... . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
12 | Bracket clamping handlo--------------------------------------------------------------.
13 | Bracket clamping bolt ----------------------------------------------------------------.
14 | Bracket Cross piece--------------------------------------------------------------------.
15 Belt guide clip------------------------------------------------------------------------.
16 || Belt guide handle---------------------------------------------------------------------.
17 | Belt guide plate-----------------------------------------------------------------------.
18 Chain, complete-----------------------------------------------------------------------.
19 | Nuts, Crown, 0.5 inch------------------------------------------------------------------.
20 | Rivets, button head, 0.187 inch (†) by 0.5 h
21 Rivets, countersunk head, 0.187 inch { .437 inch (ºr)----------------------------.
22 Rivets, countersunk head, 0.187 inch .625 inch---------------------------------
23 Side piece--------------------------------------------------------------------------...-
24 Side piece reinforce (lower)--------------------------------------------------. . . . . . . . . . .
25 | Side piece reinforce (upper)------------------------------------------------------------
26 || Spacer, A=1.85 inches.----------------------------------------------------------------.
27 | Spacer, A=3,125 inches--------------------------------------------------------.........
1
y
º
86 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
ANTIAIRCRAFT IMPROVISED POST MOUNT.
t (Plates 34, 35, 28, 36, 37, 38, 39.)
1. Description.—The Improvised Post Mount for machine guns is
designed as a semifixed mount for use in the defense of rear areas.
It consists simply of a steel spike, to be driven into the top of a
wooden post or steel pipe; a cast metal bracket designed with a
bronze bushing, which is mounted on the steel spike and swings
about it horizontally; and a round steel washer which fits over the
steel spike, against the wooden post top, underneath and forming a
bearing for the bracket in its rotation.
The upper end of the bracket is designed to receive the adapters
furnished with it for the following machine guns:
Browning Machine Gun, Model of 1917, or Vickers Machine Gun,
Model of 1915. Use Browning and Vickers Adapter.
Marlin Aircraft Machine Gun, Model of 1917, or Marlin Tank
Machine Gun, Model of 1918. Use Marlin Adapter.
Lewis Machine Gun, Model of 1917. Use Lewis Adapter.
Hotchkiss Machine Gun, Model of 1914. Use Hotchkiss Adapter.
Browning Automatic Rifle, Model of 1918. Use Browning Auto-
matic Rifle Adapter. *
These adapters are interchangeable on the Antiaircraft Machine
Gun Tripod, Model of 1918, and the Antiaircraft Machine Gun
Mount, Cygnet type, and have clips for attaching ammunition boxes
when for use with belt-fed guns.
2. Directions for setting up and use.—Drive the steel pin or spike
into the top of a wooden post, steel pipe, or other convenient support.
Place the steel washer over the pin so that it rests on the support.
Slide the bracket sleeve over the pin, base resting on the steel
washer. Attach the gun adapter to the upper end of the bracket, by
bringing the mounting pinholes of adapter and bracket into line,
inserting and locking the pin. Mount the gun on the adapter and
fasten by pins, as provided with each adapter for the gun for which
designed. -
The wooden post or steel pipe used as a support should be driven
into, or planted in, the ground Solidly, and so placed that the gunner
can walk around it without interference with anything. Its height
should be such that a gunner can assume a comfortable standing or
crouching position for all angles of fire. It has been found good
practice to plant the post in the center of a circular pit of sufficient
depth to afford cover to the gunner against ground fire.
PLATE 34.
2 * > 8
ANTIAIRCRAFT IMPROVISED POST MOUNT, ASSEMBLED.

PLATE 35.
ANTIA|RCRAFT | IMPROVISED POST MOUNT.
D IS MOUNTED,



88
PLATE 36.
IMPROVISED POST MOUNT, ANTI-
AIRCRAFT, AS USED WITH
BROWN ING MACHINE GUN,
MODEL OF 1917, WITH TRENCH
SIGHT, BROWN ING AND WICK-
- - ERS ADAPTER, BROWN ING
STOCK AND AMMUNITION BOX
AND CARTRIDGE BELT GUIDE.
-
-
|
-
IMPROVISED POST MOUNT, ANTIAIRCRAFT, AS USED WITH LEWIS
MACHINE GUN, MoDEL of 1917, WITH TRENCH SIGHT AND LEWIS
ADAPTER.
89











PLATE 37.
IMPROVISED POST MOUNT, ANTIAIRCRAFT, AS USED
WITH BROWN ING AUTOMATIC RIFLE, MODEL OF
1918, WITH TRENCH SIGHT AND 40-ROUND MAGA-
Z|N E.

- PLATE 38.
-
-
- IMPROVISED Post MoUNT, ANTIAIRCRAFT, AS USED WITH VICKERS
MACHINE GUN, MoDEL of 1915, VICKERS SHOULDER STOCK,
BROWN ING AND WIcke Rs ADAPTER, VICKERS AMMUNITION BOX
AND CARTRIDGE BELT GUIDE. THE GUN IS FITTED WITH AN IN-
FANTRY coPRECTOR SIGHT, NOW DISCARDED FOR PEYCRU SIGHT.
91


PLATE 3.9.
| MPROVISED POST MOUNT, ANTIA|RCRAFT, AS USED
WITH HOTCH KISS MACHINE GUN, MODEL OF 1914,
WITH HOTCH KISS ADAPTER AND HOTCH KISS
SHOULD ER STOCK. G.U.N FITTED WITH | NFANTRY
CORRECTOR SIGHT, NOW DISCARDED FOR PEYCRU
SIGHT.
4)2

2
ANTIAIRCRAFT MATERIEL FOR MACHINE GUINS. 93
List of parts of Antiaircraft Improvised Post Mount for machime guns.
NO Name of part. . Spares.
1 | Bracket--------------------------------------------------------------------- 1 |----------
2 | Bushing--------------------------------------------------------------------- 1 |----------
3 | Bracket pin ----------------------------------------------------------------- 1 - - - - - - - - - -
4 || Bracket bearing Washer............ -----------------------------------------. 1 - - - - - - - - - -
5 | Bracket trunnion pin.------------------------------------------------------- 1 1
6 | Locking screw.-------------------------------------------------------------- 1 1
7 | Pins, 0.125 by 0.375 inch.............. --------------------------------------. 2 - - - - - - - - - -
8 | Chain (bracket trunnion pin), complete................. -------------------. 1 1
Including:
3.5-ounce Steel chain, 7.5 inches long. --- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1
1.25 inch by 1 inch steel ring
0.125 by 0.375 inch steel ring
Chain rivet -
And 1 Cartridge Belt Guide, complete (issued for belt-fed guns). (For list of
parts see p. 159.)
And 1 Adapter for Browning and Vickers Machine Guns, complete. (For
list of parts see p. 126.) -
Or 1 Adapter for Marlin aircraft and Marlin Tank Machine Guns, complete.
(For list of º See p. 129.)
Or 1 Adapter for Lewis Machine Gun, complete. (For list of parts see p. 130.)
Or 1 Adapter for Hotchkiss Machine Gun, complete. (Forlist of partssee p.130.)
Or 1 Aºpter for Browning Automatiº Rifle, complete. (For list of parts see
D.
s' s = • * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
ANTIAIRCRAFT MACHINE GUN TRIPOD, MODEL OF 1918.
(Plates 40, 41, 42, 43, 44, 45, 53, 54.)
1. Description.—The Antiaircraft Machine Gun Tripod, Model of
1918, was designed to provide a convenient means of supporting a
machine gun at a convenient height, approximately 5 feet above the
ground, at the same time allowing it to be freely rotated by hand
in a horizontal plane and freely varied in elevation from about 15°
below horizontal to absolutely vertical position.
The tripod consists of three legs of T section steel, each clamp-bolt
pivoted at the upper end in embracing lugs projecting from the
Outer circumference of a three-section steel band collar that is
slidingly mounted on a steel tube forming a vertically adjustable
center post. The legs are shod with malleable iron or cast steel feet
similar to those used on the Machine Gun Tripod, Model of 1917
(Browning). The steel tube center post terminates at the top in a solid
steel plug, cross pinned in the tube, which has a stop flange abut-
ting the tube end, surmounted by a crown-nut-tipped pin extension
Whereon the gun mounting bracket is pivoted. The bracket used on
this tripod is the same as used on the improvised post mount and
interchangeable with it.
At the lower end of the center post, or elevating tube, is fastened
a three-lugged collar with a leg brace of strap steel bolt-pivoted to
each lug. Along the side of the shank of the T of each leg, toward
the ground, is a series of headed steel studs. The outer end of each
leg brace has a transverse inverted keyhole slot which engages in
certain position and locks on a stud in the nearest leg. The height of
94 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
the tripod is regulated by the amount of spread given to the legs
and the height of the studs engaged by the outer ends of the leg
braces. When in desired position it may be clamped against
spreading by tightening the clamping bolts which hold the leg tops
in the three-section sliding collar, thus tightening the collar lugs on
the legs and the collar against the elevating tube. The bottom of
the elevating tube is provided with a hook ring, or anchor clevis,
for roping down the tripod to its base, as when used mounted on the
Sechler trailer.
(GN - -
- \ \ &\-
(> \\ * ſºn
s
*—
WT
PLATE 40.-Antiaircraft Machine Gun Tripod, Model of 1918.
For transportation the bracket may be removed and the legs and
braces folded up. The tripod weighs, approximately, 60 pounds.
The upper end of the bracket is designed to receive the adapters,
furnished with it, for the following machine guns:
Browning Machine Gun, Model of 1917, or Vickers Machine Gun,
Model of 1915. Use Browning and Vickers Adapter.
Marlin Aircraft Machine Gun, Model of 1917, or Marlin Tank
Machine Gun, Model of 1918. Use Marlin Adapter.
Lewis Machine Gun, Model of 1917. Use Lewis Adapter.
Hotchkiss Machine Gun, Model of 1914. Use Hotchkiss Adapter.
4ts


PLATE 41.
ANTIAIRCRAFT MACHINE GUN TRIPOD, MODEL OF 1918, AS USED WITH BROWN-
ING MACHINE GUN, MoDEL of 1917, WITH SHOULDER STOCK, BROWN ING
AND WICKERS ADAPTER, TRENCH sighT, BROWN ING AM MUNITION BOX
AND CARTRIDGE BELT GUIDE.
152585–20–7. 95

PLATE 42.
ANTIAIRCRAFT MACHINE GUN TRIPOD, MODEL OF 1918, AS USED WITH VICKERS
MACHINE GUN, MODEL OF 1915, VICKERS STOCK, BROWN ING AND WICKERS
ADAPTER, VICKERS AMMUNITION BOX AND CARTRIDGE BELT GUIDE, THE
GUN IS EQUIPPED WITH THE INFANTRY CORRECTOR SIGHT, NOW DISCARDED
FOR PEYC RU SIGHT.

96
--
PLATE 43.
ANTIA RcRAFT MACHINE GUN TRIPOD, MODEL of 1918. As use D WITH MARLIN
TANK MacHINE GUN, MoDEL of 1918, TRENCH SIGHT, MARLIN STOCK,
MARLIN ADAPTER, B.Row NING AMMUNITION Box AND CARTRIDGE BELT
GUIDE.
97.


PLATE 44.
. . . . .
* * * * ****
ANTIA RCRAFT MACHINE GUN TRIPOD, MODEL OF 1918, AS USED WITH LEWIS
MACHINE GUN, MoDEL of 1917, TRENCH sighT, AND LEWIS ADAPTER.

9S
PLATE 45.
ANTIAIRCRAFT MACHINE GUN TRIPOD, MODEL OF 1918, AS USED WITH HOTCH-
KISS MACHINE GUN, MODEL OF 1914, GUN FITTED WITH INFANTRY COR-
RECTOR SIGHT, NOW DISCARDED FOR PEYCRU SIGHT, HOTCH KISS SHOULDER
STOCK AND HOTCH KISS ADAPTER,
Qº)

100 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
Browning Automatic Rifle, Model of 1918. Use Prowning Auto-
matic Rifle Adapter.
These adapters are interchangeable on the Antiaircraft Impro-
vised Post Mount, and the Antiaircraft Machine Gun Mount, Cygnet
type, and have side clips for attaching ammunition boxes when de-
signed for use with belt-fed guns. -
2. Directions for setting up and use.—The tripod legs should be
unfolded and spread to suit the height at which it is desired to
mount the gun. The outer ends of the leg braces should then be
engaged with the leg studs that suit the desired height and leg spread.
The feet of the tripod should be firmly planted in the ground, two
legs forward and one to the rear; the rear leg being placed in the
position in which the gunner will mainly operate, as giving great-
est stability. The general stability of the tripod will of course
depend upon its height and leg spread, which the gunner must ad-
just to meet the conditions. The legs may be weighted down and the
gun can be supported to Some extent by the shoulder stock bearing on
the gunner's shoulder. It is desirable to adjust the height so that the
gunner can conveniently fire at all normal elevations without inter-
ference with the tripod legs while walking around the mount, or
necessarily assuming a strained, crouching position while firing or
following the aircraft target with the gun.
After the tripod has been set in proper position, lock it there by
tightening the clamp collar, clamping legs and elevating post. Place
the bracket in place by sliding its sleeve over the mounting pin
upper terminus of the tripod. Attach to the bracket the proper
adapter for the gun to be used, by means of the registering holes in
bracket and adapter and the pin provided. Then mount the gun
on the adapter by the similar means provided. The gun when
properly mounted on the tripod will, if released, hang in an approxi-
mately vertical position, pointing upward.
When a belt-fed gun is being used, the ammunition box is now
attached to the clip for it on the adapter; in the case of the Vickers
gun the provided ammunition box container or basket being first
attached to the clip. The cartridge belt being fed into the gun and
the cartridge-belt guide placed on the ammunition box, the gun is
ready for use. g
NOTE.-The foregoing description and directions should be read on plate 52,
the tripod shown in the other, photo, views being of the first design, Subse-
quently modified in details, as regards feet, etc.
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUINS.
List of parts of Antiaircraft Machine Gum Tripod, Model of 1918.
101
NO Name of part. § Spares.
1 | Adapter bracket-----------------------------------------------------------, - - 1 ----------
2 | Anchor clevis---------------------------------------------------------------- 1 |----------
3 | Bolt, 0.375 inch by 3.301 inches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ||----------
4 || Bracket trunnion pin. -------------------------------------. - - - - - - - - - - - - - - - - - 1 ----------
5 | Bushing--------------------------------------------------------------------- 1 ----------
6 | Chain (bracket trunnion pin), complete. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
Including: -
3.5-ounce steel chain, 7.5 inches long. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.
0.125 inch by 0.1 inch steel ring--------------------------------------- 1
0.125 inch by 0.375 inch steel ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Chain rivet ----------------------------------------------------------- 1
7 | Clamp bolts.---------------------------------------------------------------- 3 1
8 Clamp nuts.---------------------------------------------- ------------------- - 3 1
9 | Elevating tube, 1.25 inch standard pipe. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
10 | Elevating tube and leg braces . . . . . . . . . . . . . . . . . . . . . . . ---------------------- 3 - - - - - - - - - -
11 | Elevating tube clamps - ---------------------------------------------------- 3 - - - - - - - - - -
12 | Elevating tube plug--------------------------------------------------------- 1 ----------
13 | Legs.------------------------------------------------------------------------ 3 ----------
14 | Leg brace bracket----------------------------------------------------------- 1 ----------
15 Leg brace catches ----------------------------------------------------------- 18 ----------
16 | Leg brace pins--------------------------------------------------------------- 3 |----------
17 | Leg shoes-------------------------------------------------------------------- 3 ||----------
18 || Locking screw--------------------------------------------------------------- 1 |
19 | Name plate ----------------------------------------------------------------- 1 !----------
20 | Nut, crown, 0.375 inch------------------------------------------------------- 1 1
21 | Nut, Crown, 1 inch . . .------------------------------------------------------ 1 ----------
22 || Pins, bronze, 0.125 inch by 0.375 inch. --------------------. . . . . . . . . . . . . . . . . . . 2 ----------
23 || Pins, split, 0.093 inch by 0.75 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . ---------------- 6 3
24 || Pin, split, 0.093 inch by 1 inch-------------------------------------------- --- 1 I
25 | Pin, Split, 0.203 inch by 2 inch----------------------------------------------. 1 1.
26 || Pins, steel, No. 10 (0.191 inch) by 1.687 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 :----------
27 | Pin, steel, No. 10 (0.191 inch) by 2.187 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
28 Rivets, buttonhead, 0.312 inch by 1 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 ----------
29 Screws, roundhead, 0.25 inch by 0.375 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ----------
30 | Washers, 0.375 inch---------------------------------------------------------- 11 3
31 | Washer, 1 inch. . . . . . . . . --------------- * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 1 ! ----------
Andi Cartridge Belt Guide, complete (issued for belt-fed guns). (For list of
parts see p. 1859.)
And 1 Adapter for Browning and Vickers Machine Guns, complete. (For list
of parts see p. 126.
Or 1 Adapter for Marlin Aircraft and Marlin Tank Machine Guns, complete.
(For list of parts see p. 129.
Or 1 Adapter for Lewis Machine Gun, complete. (For list of parts see p. 130.)
Or 1Adapter for Hotchkiss Machine Gun, complete. (For list of partssee p. 130.)
Or 1 * for Browning Automatic ižiše, complete. (For list of parts see
p. 133.
ANTIAIRCRAFT MACHINE GUN MOUNT, CYGNET TYPE, MOUNTED
ON CYGNET TRAILER, WITH AMMUNITION TRAILER.
(Plates 51, 52,46, 47, 48,49, 50.)
1. Description.—This trailer mount, designed and developed by the
Cygnet Manufacturing Co. (Inc.), of Buffalo, N. Y., provides an
antiaircraft mount for machine guns which permits a fixedly
mounted gun to be clamp controllably traversed through a complete
circle horizontally, and rapidly mechanically traversed from approx-
imately 15° below horizontal to vertical angle of elevation.
The mount consists of a low-type pedestal which supports on ball
bearings a hubbed center shaft, and elevating tube, a gunner's seat
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#
PLATE 47.
ANTIAIRCRAFT MACHINE GUN MOUNT, CYGNET TYPE, ON CYGNET TRALLER WITH AMMUNITION
TRALLER, witH LEWIS MACHINE GUN, LEWIS ADAPTER, AND TRENCH SIGHT.

#
PLATE 48.
ANTIAIRCRAFT MACHINE GUN MOUNT, CYGNET TYPE, ON CYGNET TRALLER WITH AMMUNITION
TRALLER, WITH VICKERS MACHINE GUN, MODEL OF 1915, VICKERS AMMUNITION BOX WITH
CARTRIDGE BELT GUIDE. G.U.N FITTED WITH INFANTRY CORRECTOR SIGHT, NOW DISCARDED
FOR PEYCRU SIGHT.

PLATE 49.
5
ANTIAIRCRAFT MACHINE GUN MOUNT, CYGNET TYPE, ON CYGNET TRALLER WITH AMMUNITION TRALLER,
WITH MARLIN TANK MACHINE GUN, MODEL OF 1918, BROWNING AMMUNITION BOX WITH CARTRIDGE
BELT GUIDE, MARLIN ADAPTER AND TRENCH SIGHT.

=
PLATE 50.
ANTIAIRCRAFT MACHINE GUN MOUNT, CYG NET TYPE, ON CYG NET TRAILER WITH AMMUNI-
TION TRAILER, WITH HOTCH KISS MACHINE GUN, MODEL OF 1914, HOTCHKISS ADAPTER
AND SHOULDER STOCK AND INFANTRY CORRECTOR SIGHT, NOW DISCARDED IN FAVOR
OF PEYCRU SIGHT.

ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 107
being bracketed to one side of the hub and swinging with it. The
hub and pedestal are designed so that the gun may be freely and
completely rotated but instantly clamped at any point of rotation,
by means of a handle clamping device. The gunner's seat is adjust-
able in height on the seat bracket.
The elevating mechanism consists of three tubes, the outer tube,
which forms a guiding shaft, being fastened rigidly to the hub,
clamped by an adjusting nut at the bottom of the pedestal. The
elevating tube proper slides in the outer tube, having a bushing at
its lower end and its upper end fastened rigidly to a gear case. The
inner or elevating screw tube is fastened at the bottom of the pedestal
to the adjusting screw nut and has in its upper end a threaded bush-
ing which engages the elevating screw. The elevating Screw,
mounted in the bevel-gear casing on the head of the main elevating
tube, which supports the gun arm, is operated by a handwheel,
located at the left side of the gunner when seated. -
The gun arm is pivoted in a bearing formed by the cap of the
gear case. The rear end of the gun arm is connected to the hub by
a rod extension which forms an elbow joint with it. When the gun
arm bearing is elevated the elbow straightens as the rear end of the
arm is pulled down, elevating the gun muzzle; when the mount head
is lowered the elbow angle becomes acute, the rod pushing up the
rear end of the gun arm and depressing the gun muzzle. The outer
or forward end of the gun arm bears a pivot yoke in which the vari-
ous types of adapters are mounted. Bolted to this pivot yoke is a
short worm arm bearing on the upper side of its rearward end a
telsecoping screw-adjusting post which engages the rear of the gun
adapter, and on its under side a worm which engages a segment of
gear bolted across the gun arm, to provide mechanical means, oper-
ated by a worm knob at the gunner's left, for traversing gun fire
laterally through a limited arc. The worm may be released from
the gear to allow free traversing by hand, if desired, by turning a
knob in the worm arm.
The following machine guns may be used on this mount when the
adapter designed for each gun is used:
Lewis Machine Gun, Model of 1917. . Use Lewis Adapter.
Browning Machine Gun, Model of 1917, or Vickers Machine Gun,
Model of 1918. Use Browning and Vickers Adapter.
Marlin Aircraft Machine Gun, Model of 1917, or Marlin Tank Ma-
chine Gun, Model of 1915. Use Marlin Adapter.
Hotchkiss Machine Gun, Model of 1914. Use Hotchkiss Adapter.
Browning Automatic Rifle, Model of 1918. Use Browning Auto-
matic Rifle Adapter.
º
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PLATE 51,–Antiaircraft Machine Gun Mount, Cygnet type, on Cygnet Trailer with Ammunition Trailer. (Showing Mount Trailer only.)
^


ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 109
These adapters are interchangeable on the Antiaircraft Improvised
Post Mount and the Antiaircraft Machine Gun Mount, Model of
1918, and have side clips for the attachment of ammunition boxes
when designed for use with belt-fed guns.
MOUNT TRAILER.
(Plate 51.)
The trailer is designed to carry the mount and consists of a frame
of steel tubing, braced by a truss rod on the under side, with three
frame-connection castings through which three tubular anchor legs,
clampable in position, slide into contact with the ground. These legs
are used to elevate the wheels from the ground, forming when
dropped a tripod on which the frame rests, providing a steady, rigid
base for the gun mount. -
The front end of the trailer is fitted with a tubular steel cross bar
or handle, to be used when hauling by hand, and eyelet ring, to be
used when being hauled by motor or other means. The rear end
of the trailer is provided with a hook, on which the forward end of
the ammunition trailer may be hitched. The trailer is equipped with
two wire wheels of motor cycle type, pneumatic tired, with inward
hub band brakes, controlled by a ratchet-lever control handle.
A complete spare wheel, with rubber tire attached (28 inches by
3 inches), is carried horizontally between the frame and truss rod
and held in place by clamp bolts fastened to the frame.
A tool box is bolted to the frame and carries the following tools:
For mount—oiler with cap, screwdriver, wrench; for trailer—cycle
tire repair kit, tire pump, tire iron, wheel wrench.
AMMUNITION TRAILER.
(Plate 52.)
This trailer is designed to carry ammunition and consists of a
wheel mounted steel tube frame of approximately triangular shape,
which bears a steel plate ammunition chest, reinforced by a wooden
frame lining. In a triple connection casting in the front part of the
trailer frame a tubular anchor leg with disked foot, same as in trailer
mount, is clampably held in desired position. The wheels are the
same as in the mount trailer, 28 inches by 3 inches, pneumatic tired,
motorcycle type, and controlled by an inward hub brake band con-
nected to a ratchet lever handle. The front end of the trailer frame
is equipped with a tubular cross bar for hauling by hand and an eye-
let for attachment to the hook on the rear of the mount trailer or
hitching to another vehicle.
The ammunition chest, which is bolted to the trailer frame, opens
at the top, the lid being fastened to the chest by four hinges and
alºfº'ſ
w
L
Aº
2* - *—e.
A37
AMºſcº/
Jozº)
Jøſ /24/7.'
PLATE 52.—Antiaircraft Machine Gun Mount, Cygnet type, on Cygnet Trailer With Ammunition Trailer. (Showing Ammunition Trailer only.)
E
^







ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 111
two hasps, one secured by a chained snap hook and the other by a
chained padlock. The chest has been designed to carry the Lewis
machine gun, which straps tightly to gun brackets within the chest.
It carries in addition to the gun one 1,200-round box of ammunition
and two 6-magazine pan boxes; spare parts for the gun, trailer, and
mount, and extra inner tubes for tires. The machine gun cleaning
rod is clamped to the under side of the chest lid. º
NOTE.—The foregoing description should be read on Plates Nos. 51 and 52.
made from the latest drawings. The photographic plates illustrating the use of
the various machine guns on the Cygnet Trailer Mount with Ammunition Trailer,
show the earlier model of the trailer, with side Opening ammunition chest
designed to carry only ammunition boxes; no tool chest; hook where eyelet
is now, etc. - -
General data.
Diameter of wheels— ..— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — inches__ 28
Vertical travel of elevating gear do–––– 15
Maximum height from ground level to center line of elevating hand
Wheel ---------------------------------------------------- inches – 51.2
Width over all----------------------------------------------- do———— 61. 75
Wheel tread------------------------------------------------- do–––– 56
Center line of. Wheels to eyelet--------------------------------- dO____ 60. 187
Weight of mount, low pedestal------------------------------ pounds__ 140
Weight of mount trailer–––––––––––––––––––––––––––––––––––––– do–––– 200
Weight of ammunition trailer--------------------------------- do–––– 180
Total Weight, complete---------------------------------------- do–––– 520
2. Directions for setting up and use.—The trailer mount should be
elevated from the ground by unclamping, dropping below wheel base,
and reclamping the anchor legs; disposing them, according to the
nature of the ground, to level the gun mount as on a rigid tripod.
If in emergency the mount should be used while resting on the wheels,
the brakes should of course be first applied.
After mounting the machine gun on its adapter and the gun and
adapter on the pivot yoke of the mount head, by means of the regis-
tering holes and attaching pins provided, the gunner takes his posi-
tion on the seat and operates the mount as follows:
To turn the mount laterally, loosen the clamp on the hub at the
gunner's left side; the seat and hub then swing horizontally, together
with the mount head. By loosening the clamp collar. handle just
above the hub at the gunner's right side, and tightening the hub
clamp, the mount above the hub may be rotated, leaving the seat in
fixed position. The gunner may thus swing freely with the gun, to
right or left or all around the circle, or swing it to one side or other
from a fixed seat. He may also leave the seat and fire from a stand-
ing position.
When quick elevation is desired the elevating handwheel should be
turned toward the gunner, on the upper turn, he operating the wheel
with his left hand. To obtain additional vertical adjustment, un-
152535–20––8
112 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNs.
clamp the elevating nut below the rear end of the gun adapter, by
turning the elevating nut knob at the gunner's left side, and then
turn the adapter screw knob which is fastened to the adapter adjust-
ing screw, until the desired adjustment is obtained.
The worm and gear wheel segment is used to obtain exact lateral
adjustment, by turning the worm shaft knob with the left hand. To
obtain free and rapid adjustment at this point, disengage the worm
from the gear segment by turning the cam lever located on the right
side of the worm arm.
The worm locking device may be adjusted by loosening the set
screw which locks the adjusting screw located between the worm arm
flanges, then removing the small plug located on top of the arm, in-
serting a screw driver and turning the small adjusting screw against
the cam spring, until adjusted as desired.
The meshing of the worm with the gear segment is adjusted by
loosening the hexagonal nut on top of the arm and turning the ad-
justing Screw. - - +
TRAVELING ORDER.
To avoid breakage when traveling the machine gun must be
clamped tightly to its brackets, and spare parts in chest and tools
carefully packed. It is very important to have the elevating or
anchor legs on the trailers drawn up as high as possible and tightly
clamped to prevent their dropping against the ground while travel-
ing. The chained cotter pin for the draw hook must be used, to pre-
vent jolting disengagement of the trailers from each other, by the
lunette, or eyelet, and hook separating.
The brakes on the trailers are adjusted by means of the nuts on the
brake adjusting bolts.
The anchor legs may be removed from the trailer frames, if neces-
sary, by loosening the clamp, removing the top handle by driving
out the tapered cross pin, and pulling the leg out of its housing, from
below. . -
3. Directions for assembling (mount).--To attach the hub and
outer elevating tube, or guide casing, to the pedestal, place the ball
bearings in position and slide the tube down through the bottom of
the pedestal. Screw the adjusting nut up tight against the ball
bearing and bearing washer at the bottom of the pedestal and apply
the jam nut, locking the jam nut with the small set screw. .
To assemble the elevating mechanism, screw the elevating screw
into the elevating screw tube, or inner tube; insert latter through the
elevating collar, tube bushing, and bevel gear; put on the hexagonal
nut which prevents the gear from being removed.
To assemble the elevating mechanism to the mount, place the
clamp collar over the hub; put the clamp-jam nut, hub-bushing nut,
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNs. 113
felt washer and hub bushing over the elevating tube; screw the
elevating-tube bushing on the elevating tube, locking the bushing
with the set screw, turned in sufficiently to be flush with the outer
surface of the bushing. Insert the complete elevating mechanism
into the assembled pedestal; apply the hexagonal nut under the jam
nut, which fastens the elevating mechanism to the pedestal; place the
hub bushing down against the outer (casing) tube; tighten the clamp-
jam nut against the clamp collar; place the felt washer down tightly
against the hub bushing; screw the hub-bushing nut tight against
the jam nut, applying locking screws in jam nut and bushing nut;
then turn the clamp handle until the hub is clamped tightly against
the pedestal. Place the double-flanged bushing in the gear case;
mesh the vertical gear with the horizontal gear; drive the handwheel
shaft through hole in gear; apply the single-flanged bushing to the
gear case; bolt the gear-case cap to the gear case, and fasten the
elevating handwheel to the shaft with set screws.
To assemble the gun arm to the mount, attach the center of the gun
arm to the cap of the elevating gear case, by means of pivot pin pro-
vided, and bolt the gun-arm connection, or elbow rod, to the hub
clamp and rear end of gun arm. -
To attach the assembled worm arm and pivot yoke to gun arm,
turn same at right angle and insert in hole located at end of gun
arm; when turned to firing position a locking screw in bottom of
arm prevents the yoke from being removed.
To assemble the worm to the worm arm, place the worm in the
worm bracket and insert the worm shaft, locking shaft by screwing
the locking screw into the worm bracket, then bolt the bracket to the
WOI’ll] & TIY).
The gear segment is attached to the gun arm by hexagonal head
SCTOWS.
Assembling trailers.-Assemble the wheels to frame by fitting
on axle, putting on ball-bearing washer and castellated nut; tighten-
ing nut until wheel is snugly mounted, and screwing outer cap on Wheel
hub. Place the anchor legs in position in the frame by loosening
leg clamp in frame, removing handle from top of anchor leg by driv-
ing out tapered cross pin, inserting leg in frame housing from below,
and replacing leg handle. Clamp the anchor legs in high position.
Set brake-control lever in proper working position on trailer frame,
cotter-pinned to brake-connecting rod and fastened to brake-lever
casting stud by washered nut. Tighten in place the cap screws
fastening brake-segment rack to brake lever bracket and the bolts
attaching the bracket to frame. Set brake bands in order by ad-
justing band bolt as required.
4. Dismounting mount and trailers.--To dismount, reverse the as-
sembling operations.
114
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
List of parts of Antiaircraft Machine Gun Mount, Cygnet type, mounted on
Cygnet Trailer with Amymºunition, T'railer.
TRAILF. R. PARTS,
NO Name of part. Nº Spares.
1 | Band, brake. ---------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • 2 . . . . . . . . . .
2 | Base, tool chest....-----------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .
3 É. brake rod. ------------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
4 | Body, tool chest.--------------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
5 | Bolts, 0.375 inch by 1.5 inches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3
6 Bolts, carriage, 0.312 inch (ºr inch) by 8 inches... . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
7 | Bolt, clamp-------------------------------------. . . . . . . . . . . . . . . . . . . . . . . . . 3 1.
8 | Bolt, Spare wheel carrier... --------------.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1
9 | Bolt, U, A-0.59 § B-2.25. ---------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 |. . . . . . . . . .
1ó | Boit, Ü, A-5812 (#), B-2.438 inches (213).................................... 4 |. . . . . . . . . .
11 | Bolt, U.----------------------- • sº sº e e s sº s as s a s gº sº as as ºr e s is is is is sº is as s as sº e s as sº º is & as e s s & sº is nº sº 1 1. ---------
12 | Bolt, U---------------------- A s = * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 4 3
13 | Bottom, tool chest... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 |. . . . . . . . . .
14 | Bracket, brake lever. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 |. ---------
15 | Cap, Spare Wheel dust. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
16 | Carrier, Spare wheel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 |... --------
17 | Catch, brake lever........................................................... 1 |. . . . . . . . . .
18 Chain, complete. ----------------------------------------------------. . . . . . . . 1 1
Consisting of: . -
1 steel safety chain, No. 1 commercial, 5 inches long.
1 split pin, 0.25 inch by 1.5 inches.
19 | Clip----------------------------------------------------------------------. 2 1
20 | Clip. . . . . . . . . . . . . , as tº is sº * * * * * * * * * * * * * * * * * g is a s as sº e º sº sº s as s = <s as a s = s. s e is as a e sº e s sº º is e s is is sº 2 1
21 | Clip, brake band------------------------------------. . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
22 | Clip (truss rod loop).--------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1
23 Connection, frame------------------------------ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. . . . . . . . . .
24 || Connection, frame triple. . . . . . . • * * * * * * * * * * * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 ----------
25 | Collar, brake rod. . . . . . . . . . . . . . . . . . . . . . . . & º ºs º gº tº º º ºs º º ºs s ºf sº ºr nº & º ºs º ºs & E * * * * * * * * * & ſº * 2. l. . . . . . . . . .
26 | Filler, brake rod.bearing.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . .
27 | Handle, anchor leg. . . . . . . . . . . . . . . . . . . . . . . . . . * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3 1. . . . . . . . .
28 || Hinge (female), tool chest.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . ----
25 | Hinge (male), tool chest................................................... 2 . . . . . . . . . .
30 | Hook, draw. -------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 |. . . . . . . . . .
31 | Lever, brake quadrant.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .
32 | Lever (double), brako rod. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
33 | Lever (single) brake rod.............' ...................................... 1 . . . . . . . . . .
34 || Lid, tool chest. . . . . . . . .... * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 1 |. . . . . . . . . .
35 | Lining, brake §. or equal). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2
36 | Lock (No. 1586 Yale or equal). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * 1 . . . . . . . . . .
37 || Loop, truss rod.-----------------------------------. . . . . . . . . . ... * * * * as sº sº as as º ºs ºs º ºs 1 . . . . . . . . . .
38 Lug, clamp--------------------------------------------- . . . . . . . . . . . . . . . . . . . . . 3 1
39 Lunette- - - - - - ----------------------------------------. . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .
Nuts:
40 0.375-inch. ------------------------------------------ . . . . . . . . . . . . . . . . . . . . 12 4
41 0.375-inch, U. S. Standard thread, 24 per inch . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
42 0.375-inch, U. S. standard thread, 24 per inch . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2
43 0.5-inch------------------------------- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
44 15 left hand thread. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
Nuts, square:
45 0.312-inch (*)--------- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * * * * * * * * * . 26 6
46 Nut, axle.------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • * * * * * * * 2 1
47 Nut, carrier bolt wing. . . . . . . • * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 4 1
48 Nut, clamp--------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1
49 Nut, dust Cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.
50 Nut, truss rod connection. . . . . . . . . . . . . . . . . . . .... • * ~ * * * * * * * * * * * * * * * * * * * * * * * * 1 1
51 Peg, anchor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - - - - - 3 . . . . . . . . .
52 Pin (19mg), Clévis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1
53 Pin (short), clevis. . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2 1
Pins, split: .
54 l 0.093 inch (#4) by 0.75 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3
55 0.125 inch by 1.75 inches. . . . . . . . . . . . . . . . . -a < e s = s. s as s s as sº sº e < * * * * * * * * * s ºf s is & sº * * 2 1
Pins, steel:
, 56 0.125 inch by 2.125 inches. . . . . . . . . . . . . . . . . . . . . . . . ,- - - - - - - - - - - - - - - - - - - - - - - - 2 1
57 0.187 inch (ºr) by 0.625 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . . .
58 0.187 inch (ºs) by 1 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . s 1. 2
59 0.375 inch by 3.5 inches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.
60 No. 10, 0.191 by 1.375 inches... . . . . . - * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 7 . . . . . . . . . .
61 No. 10, 0.191 by 1.5 inches... . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3 . . . . . . . . . .
62 No. 10, 0.191 by 1.75 inches... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 . . . . . . . . . .
63 No. 10, 0.191 by 1.875 inches... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - - - - - - - - - - 4 5
64 Pins, taper, 0.208 inch by 1.5 inches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1
65 Plate, anchor------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . . . . . . . . . .
66 Plate, name. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , - - - - - - .* 1 : - - - - - - - - - -
67 Plug, brake lever. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - - - - - - - - - - - - - 1 : . . . . . . . . . .
68 Rack, brake segment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • - - 1 . . . . . . . . . .
2

Rest, truss rod. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
a s = e s ºf s = * * *
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
115
List of parts of Antiaircraft Machine Gun Mount, Cygnet type, etc.—Continued.
TRAILER PARTS-Continued.
|
Nº. 1.
NO Name of part. Rºi Spares.
Rivets (steel): *
70 0.125-inch by 0.687-inch (+4) countersunk head. . . . . . . . . . . . . . . . . . . . . . . . . . . 12 12
71 1.25-inch by 0.25-inch, round head. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 : . . . . . . . . . .
72 0.25-inch by 0.625-inch, 1ound head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 i. . . . . . . . . .
73 Rod, brake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .* - - - - - - 1 : . . . . . . . . . .
74 Rod, brake connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .
75 Rod (front), truss. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .
76 Rod (rear), truss. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .
Screws, round head:
77 0.191 inch (No. 10) by 0.375 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. 1
78 0.25 inch by 0.375 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
Screws, hexagonal head cap: -
79 0.312-inch (*) by 0.625-inch, United States standard thread, 24 per inch. . 2 1
80 Socket (left), ſrame Connection and leg. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .
81 Socket (right), frame connection and leg. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .
82 Spindle, axle----------------------------------------. . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
83 Spring, brake lever------------------------------. . . . . . . . . . . . . . . . . . . . . . . . I 1
84 Stud, brake lever. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
Tubes:
85 Anchor leg-------- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - 3 . . . . . . . . . .
86 Axle-------------------------------------------. . . . . . . . . . . . . . . . . . . . . . . . . 1 - . . . . . . . . .
87 (Inner), brake lever. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 | . . . . . . . . . .
88 (Quter), brake lever. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - . . . . . . . . .
89 (Center), frame--------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - . . . . . . . . .
90 (Cross center), frame. -------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ! . . . . . . . . . .
91 (Side), frame, with holes “A” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .
92 (Side), frame, without holes “A”... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .
93 Frame handle---------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ---------.
94 Lunette.---------------------------------------------------------. . . . . . 1 ! . . . . . . . . . .
95 | Washers, 0.375-inch------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
Washers, lock:
96 0.312-inch (ºs). . . . . . . . . . . . . . . . . .--------------------. . . . . . . . . . . . . . . : - - - - 30 8
97 0.375-inch---------------------------------------. . . . . . . . . . . . . . . . . . . . . . . . . 16 4
Wheels, complete ----------------------------------------------------------- 2 1
98 Each consisting of: 13, 0.375-inch balls (steel).
99 13, 0.437-inch (ºr) balls (steel).
100 1 ball Cup ( ;
101 1 ball Cup (Outer).
102 1 brake drum.
103 1 cone (inner).
104 1 cone (outer). *
105 1 dust guard.
106 1 dust washer (ſelt). w
107 1 hub.
108 1 hub cap. *
109 1 retainer ring (inner).
110 1 retainer ring (outer). .
111 5, 0.25-inch by 0.5-inch rivets (buttonhead).
112 1 rim (tire), Mott Wheel Works, or equal. &
113 40 spokes, wire, with nipples 0.134-inch diameter by 12 inches.
114 1 tire (pneumatic), 28 inches by 3 inches, complete, including inner tube,
valve, etc. ..
Yoke, brake adjusting-------------------.- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2 . . . . . . . . . .
115 To be ſurnished in addition to the above equipment: --
116 Inner tube (28 inches by 3 inches). - - - - - - - - - - - - - - - - . . . . . . . . . . . . . . . . . . . . . . 1 1
117 Blow-out patch § for 28-inch by 3-inch tire. . . . . . . . . . . . . . . - - - - - - - - - 1 - . . . . . . . . .
118 Blow-out patch (outside) for 28-inch by 3-inch tire. . . . . . . . . . . . . . . . . . . . . . . 1 - - - - - - - - - -
119 Cone (outer)------------------------------------------------ . . . . . . . . . . . . . 1 1
120 Dust washer (felt)-----------------------------. ------------------------. 1 1.
121 Hub cap- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 1
MOUNT PARTS.
1 | Arm, gun-------------------------------------------------------------------- 1 ----------
2 Arm, worm. Wheel. ---------------------------------------------------------- 1 ----------
3 Ball, 0.25-inch diameter (steel).---------------------------------------------. 1 ----------
4 Bearing, ball, complete (U. S. Ball Bearing Co. Or equal)... . . . . . . . . . . . . . . . . . . 2 ----------
Éach consisting of: -
1 ball race (inner).
1 ball race (outer).
10 balls (steel), 0.531-inch (+4).
2 ball retainers.
g 10 rivets (steel), 0.062-inch (#) by 0.125-inch.
5 || Bearing, washer º sº sº º is e s sº tº ºf º ºs e º º ºs º ºs º is º º & sº º ºs & ae s. s is a s e a s tº sº º ºs s as e º sº sº ºr sº º sº sº a s gº as ! ----------
6 Bearing, washer (ſelt).------------------------------------------------------- 2 ----------
116 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNs.
List of parts of Amtiaircraft Machine Gun Mount, Cygnet type, etc.—Continued.
MOUNT PARTS-COntinued.
y T Number
No. Name of part. required. Spares.
Bolts (U. S. standard thread):
7 0.375-inch by 1.375 inches (24 threads per º * = * * * * * * * * * * * * * * * * * * * * * * * * * * 4 1
8 0.375-inch by 1.5 inches (24 threads per inch) (low type pedestal only).... 2 1
9 0.5-inch by 2.5 inches (20 threads per inch)... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 1
10 | Bolts, carriage-------------------------------------------.................... 1 I
11 | Bolts, clamp----------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 l
12 | Bolts, clamp collar-----------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l 1
13 | Bolt, gun arm (long)---------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
14 | Bolt, gun arm (short)---------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
15 Bracket, Seat. -----------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ---------.
16. Bracket, Worm. ------------------------------------------------------------. ! ----------
17 | Bushing (double flange). . . . . . . . . . . . . . . . . . . . . . . . . . . . ......................... 1 ----------
18 Bushing (single flange).---------.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ! ---------.
19 | Bushing, elevating tube. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ................ ! ----------
20 | Bushing, elevating tube. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ---------.
21 | Bushing, hub--------------------------------------------... . . . . . . . . . . . . . . . . . 1 ----------
22 | Bushing, hub clamp--------------------------------------------------------- 1 ----------
23 Cam------------------------------------------------------------------------. 1 ----------
24 | Cap, gear case. -------------------------------------------------------------- 1 i----------
25 | Case, gear-------------------------------------------------------------------. 1 ----------
26 Casing, elevating tube. -----------------------------------------------------. 1 ----------
27 | Chain, complete (steel), consisting of:
1 safety chain, No. 1 commercial, 6.75 inches long ............................................
1 ring--------------------------------------------------------------------|------------........
28 Clamp, hub------------------------------------------------------------------ 1 ----------
29 | Collar, clamp------------------------------------------ - - - - - - - - - - - - - - - - - - - - - - 1 i----------
30 | Collar, elevating-----------------------------------------------.............. 1 ----------
31 | Connection, gun arm------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
32 | End, connection.-----------------------------------------------------------. 1 ----------
33 | Fastoner, Seat --------------------------------------------------------------- ! ----------
34 Gear, elevating . . . . . . . . . . . . . . . .* * * * * * * * * * * * * * * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2 ----------
35 | Handle, clamp.-------------------------------------------------------------- 1 ----------
36 | Handle, pivot lever---------------------------------------------------------- 1 ----------
37 | Handle, elevating handwheel... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
38 Handle, hub clamp-...------------------------------------------------------. 1 ----------
39 Handwheel, elevating. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
40 | Hub, elevating-------------------------------------------------------------. 1 ----------
41 || Knob, adapter Screw. -------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
42 Knob, elevating nut. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .
43 Knob, Worm Shaft.---------------------, ------------------------------------ 1 |----------
ICeys: -- *
44 0.125-inch Square by 1.125 inches (13)..................................... 1 ----------
45 0.187-inch § by 0.75-inch by 0.062-inch § * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 1 ----------
46 0.187-inch (†) by 0.75-inch by 0.062-inch (ºr), Woodruff.... . . . . . . . . . . . . . . 1 ----------
47 | Lever, cam-------------------------- * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * = - - - - - - - - - 1 ----------
48 Lug, clamp------------------------------------------------------------------ 1 ----------
49 uts---------* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - * * * * * * * * * * * * * * * * * * * * * * * = • * = • * ~ * 2 1
Nuts, hexagonal head, U. S. standard thread (24 per inch):
50 0.375-inch---------------------------------------------------------------. 2 1
51 0.375-inch---------------------------------------------------------------. . 4 1
52 0.375-inch by 0.375-inch thic'; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 I
53 0.5-inch (20 per inch). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1
54 Nut, adjusting---------------------......... . . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - 1 - . . . . . . . . .
55 | Nut, Cap jam ---------------------------------------------------------------- 1 ----------
50 Nut, clamp------------------------------------------------------------------ 1 ----------
57 | Nut, clamp jam. -----------------------------------------------------------. 1 ----------
Nut, crown, U. S. standard thread:
58 0.5-inch (20 threads per inch). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
59 0.5-inch § threads per § is sº a s a s e º sº a se it s = e = * * * * * * * * * * * * * * * * * * * * * * * * * g º sº 1 1
60 0.5-inch (20 threads per inch). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
61 | Nut, elevating--------------------------------------------------------------. | 1 |----------
62 Nut, hub bushing----------------------------------------------------------. 1 ----------
63 Nut, 0.375-inch, square head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 , 1
64 | Pedestal (low type)---------------------------------------------------------- ! ----------
65 | Pin, handle-----------------------------------------------------------------. 1 . . . . . . . . . .
Pins, split:
66 0.125 by 0.75 inch. ------------------------------------------------------. 1 1
67 0.125 by 1.125 inches. . . . . . . . . . . . . . . . . . . . . . . . . . --------------------------- 3 l
68 0.125 by 1.25 inches. . . . . . . . . . . . . . . . . . . . . . . . . ----------------------------. 1 1
- Pins, steel (driven):
69 0.125 by 0.312 inch (*)... . . . . . . . . . . . . . . . . . . . . ---------. • = * * * * ... • * * * * * * * * * * * * 1 ----------
70 0.125 by 0.75 inch. ------------------------------------------------------- 1 ----------
71 0.125 by 0.875 inch.... . . . . . . . . . . . . . . .- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 ----------
72 0.125 by 1 inch----------------------------------------------------------- 1 ----------
73 0.187 (ºs) by 0.437 inch (ſº). . . . . . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - 2 - . . . . . . . . .
74 0.187 (Ps) by 0.375 inch...------------------------------------------------- 2 . . . . . . . . . .
75 0.187 (Ps) by 1.375 inches.------------------------------------------------ 1 ----------
76 0.187 (Ps) by 2 inches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . --------- 1 ----------
77 0.187 § by 1.5 inches... . . . . . . . . . . . . . . . . . ------------------------------- 2 ... --------
78 0.191 (No. 10) 1,875 inches. . . . . . . . . . .--------------------------------. 1 ----------
79 0.375 by 3.5 inches. ------------------------------------------------------ 1 ----------
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
117
List of parts of Antiaircraft Machine Gun Mount, Cygnet type, etc.—Continued.
MOUNT PARTS-Continued.
No. Name of part. . Spares.
80 Pins, steel (taper), 0.162 by 1.5 inches... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -----------|..........
81 | Plate, name. ... ----------------------. . . . . . . . . . . . . . . . . . --------------------- ! ----------
82 | Plug------------------------------------------------------------------------- ! ----------
83 Plug, 0.156 inch (*) by 0.187 inch (ºs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ! ----------
84 || Plug, elevating Screw tube... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ! ----------
Rivets, steel, oval head:
S5 0.25 by 0.025 inch......-------------------------------------------------- * !----------
86 0.312 (*) by 0.75 inch... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * !----------
87 0.062 by 0.125, inch. . . . . ------------------------------------------------- % ----------
88 0.187 by 0.75 inch. . . . . . . . . . . . . . . . . . . . . . . . . .----------------------------- * ----------
89 0.25 by 0.875, inch--------------. . . . . . . . . . . . . . . . . . . . . . . ------------------ * !----------
90 | Screw º adapter adjusting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . --------- ! ----------
91 Screw (outer), adapter adjusting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ! ----------
92 Screw, elevating------------------------------------------------------------- ! ----------
93 l Screw, locking-...----------------------------------------------------------- 1 1
94 | Screw, locking--------------------------------------------------------------- 1 1
Screw, locking (pivot yoke).------------------------------------------------- I 1
95 Screw, locking.... -------------------------------- - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 1
96 Screws, steel, countersunk head: 0.216 inch by 0.5 inches..................... 2 1
97 Screws, steel, flat head, machine:
98 0.190 (No. } by 0.5 inch. ----------------------------------------------- 2 I
99 0.215 (No. 12) by 0.375 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
Screws, steel, set, headless:
100 0.375 by 1 inch (U. S. standard thread, 24 inch). . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
101 0.25 by 0.375 inch -------------------------------------------------------- 1 1
102 0.375 by 0.5 inch--------------------------------------------------------- 1 1
103 0.25 by 0.375 inch. ------------------------------------------------------- 4 1
104 0.312 (*) by 0.625 inch --------------------------------------------------- 2 l
105 0.375 by 0.375 inch. . . . . . . . . . . . . . ----------------------------------------- 1 I
Screws, steel, hexagonal head cap, U. S. standard thread: !
106 0.375 by 0.875 inch (24 threads per inch)--------------------------------. 2 1
107 0.375 by 1 inch (24 threads per inch) ----------------. . . . . . . . . . . . . . . . . . . . 3 I
108 0.375 by 2.75 inches (24 threads º inch) --------------------------------- 2 I
109 0.5 by 1 inch (20 threads per inch). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1
Screws, roundhead:
110 0.190 (No. 10) by 0.312 inch (*)....... ----------------------------------- l 1
111 0.199 (No. 10) by 0.375 inch. --------------------------------------------- 1 1
112 0.25 by 0.375 inch-------------------------------------------------------- * ----------
113 | Seat.------------------------------------------------------------------------- ! ----------
114 | Segment, Worm. Wheel. ------------------------------------------------------ ! ----------
115 Shaft, cam------------------------------------------------------------------- ! ----------
116 || Shaft, elevating-------------------------------,------------------------------- 1 i----------
117 | Shaft, elevating nut.-------------------------------------------------------- ! ----------
118 Shaft, Worm-------------------------------------------------------------... • * * = ! ----------
119 | Sleeve, elevating screw tube-------------------------------------------------|--------------......
120 | Spring, Cam ----------------------------------------------------------------- ! ----------
121 | Spring, cam locking--------------------------------------------------------- ! i---------.
122 #. Seat.--------------------------------------------------------------- ! ----------
123 Tube, elevating-------------------------------------------------------------- ! ----------
124 Tube, elevating Screw. ------------------------------------------------------ ! ----------
125 | Washer, clamp bushing------------------------------------------------------ ! ----------
126 Washer, hub clamp... -------------------------- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ! ---------.
127 Washer, felt, 0.125 by 1.875 inches, I. D. by 2.25 inches O. D. . . . . . . . . . . . . . . . . . . ! ----------
128 || Washers, lock, 0.375 inch. --------------------------------------------------- 13 3
129 Washers, lock, 0.5 inch------------------------------------------------------ 4 l
130 OTIIl- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I l
131 | Yoke, connection.----------------------------------------------------------- l 1
132 | Yoko, pivot.------------------------------------------- N- - - - - - - - - - - - - - - - - - - - - - l 1
And 1 cartridge belt guide, complete § only when mount is to be used
with a belt fed machine gun). (For list of parts see p. 159.)
And 1 adapter for Lewis machine gun, complete. (For list of parts see p. 130.)
Or 1 adapter for Browning and Vickers machine guns, complete. (For list of
parts see p. 126.) *
Or 1 adapter for Marlin aircraft and Marlin tank machine guns, complete
(For list of parts see p. 129.) , ,
Or 1 adapter for Hotchkiss machinegun, complete. (Forlist of parts see p. 130.)
Or 1 adapter for Browning automatic rifle, complete. (Forlist of parts seep. 133.)
AMMUNITION TRAIT, ER PARTS.
| }
1 | Band, brake. . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - vº - - - - - - - - - - - - - - - 2 . . . . . . . . . . .
2 | Bearing, brake rod.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - 2 - - - - - - - - - -
olts: | .
3 0.375 by 1.5 inches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1
4 0.375 by 4.5 inches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . S 2
5 | Bolt, clamp------------------------------------------------------------------ 1 ----------
6 | Bolt, U---------------------------------------------------------------------- 4 1
118
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GTUNS.
List of parts of Antiaircraft Machine Gun Mount, Cygnet type, etc.—Continued.
AMMUNITION TRAILER PARTS-Continued.
No. Name of part. § Spares.
7 | Bolt, U, A =0.593 (#), B=2.25..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
8 . Bottom------------------------------------. . . . . . . . . . . . . . . . * - - - - - - º ºs s - sº º ºr - - - - - 1 . . . . . . . . . .
9 | Bracket, brake lever. . . . . . . . . . . . . . . . . . . ,- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 . . . . . . . . . .
10 | Bracket, gun------------------------------------------------... . . . . . . . . . . . . . 1 . . . . . . . . . .
11 | Bracket, gun.-----------------------------------------.... . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
12 | Buckle, barrel roller, 1.25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
13 || Catch, brake ſever.’...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .
14 | Chain (steel), complete........................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 I
Each consisting of:
1 steel Safety chain No. 1, commercial, 5 feet long.
1 split pin, 0.25 by 15 inches. -
15 Chain, complete........................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 i. . . . . . . . . .
Each consisting of:
1 chain.
1 bolt snap.
1 chain rivet.
2 chain rings.
16 || Chain, chest, complete... . . . . . . . . . . . . . . . . . . . . ,- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - * - 2 . . . . . . . . . .
17 | Clip-----------------------------------------------------------------------. . 6 2
18 | Clip, brake band.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
19 , T00--- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2 . . . . . . . . . .
20 | Collar, brake rod.-----------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
21 | Qonnection, frame. ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 I-.........
22 | Connection, frame, triple. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ! ---. . . . . . .
23 | Cover, frame (ends). . . . . . . . . . . . . . . . . . . . . . : : - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2 . . . . . . . . . .
24 No. 24, U. S. C. sheet steel cover frame (sides and bottºm)... . . . . . . . . . . . . . . . . ! --- . . . . . . .
25 | No. 24, U. S. C. Sheet Steel cover, lid .............. . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ..........
26 | Filler, brake rod bearing...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
27 Handie, anchor leg-----------------------------------------. . . . . . . . . . . . . . . . . 1 ... . . . . . . .
28 || Hasp, hinge with staple plate, 6-inch leaf, commercial............. . . . . . . . . . . . 2 - . . . . . . . . .
29 || Hinge, 6-inch leaf, commercial.........'... .* * * * * * * * * * * * * * - - - - - - - - * * * * * * * * * * * 4 - . . . . . . . . .
30 | Hook, draw----------------------------------------------------------------- 1 ... . . . . . . .
31 | Lever, brake quadrant. . . . . . . . . . . . . .---------------------. . . . . . . . . . . . . . . . . . . 1 - . . . . . . . . .
32 | Lever (single), brake rod. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 |... . . . . . . .
33 | Lever (double), brake rod. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
34 Lid, complete.-------------------------------------------------------------- 1 --- . . . . . . .
Consisting of:
2 side pieces.
5 cross brackets.
35 | Lining, brake (Raybestos or equal)........ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.
36 | Pug, clamp------------------------------------------------------------------ 1 ... . . . . . . .
37 Lunette--------------------------------------------------------------------- 1 . . . . . . . . . .
38 || Nails, barbed flat head wire, 0.625-inch, No. 13, commercial... . . . . . . . . . . . . . . . . 32 1. . . . . . . . . .
39 || Nails, flat head Wire, 0.75-inch, No. 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 ! . . . . . . . . . .
40 | Nails, Wire, No. 11, 5 by 2inches........ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 . . . . . . . . . .
Nuts:
41 0.375 inch---------------------------------------------------------------- 12 4.
42 0.375 inch, U. S. standard thread, 24 per inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
43 0.375 inch, U. S. standard thread, 24 per inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2
44 || Nut, axle-------------------------------------------------------------------- 2 1
45 Nut, clamp------------------------------------------------------------------ 1 - . . . . . . . . .
46 Nuts, square, 0.312inch (Ps). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3
47 | Padlock (Yale No. 840 or equal). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ---------.
48 Partition “A”.-------------------------------------------------------------- 1 - . . . . . . . . .
49 | Partition “B”. . . . . . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 - . . . . . . . . .
50 | Peg, anchor------------------------------------------------------------------ 1 . . . . . . . . . .
51 Pin (long), clevis-------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1
52 || Pin (short), clevis. . . . . . • * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 2 1
Pins, split: º -
53 0.093 (#4) by 0.75 inch. . . . . . . . . . . . . . . . . . . . . . * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 6 3.
54 0.125 by 1.5 inches. . . . . . . . . . . . . . . . . . . . . . . . .------------------------------ 2 1.
Pins, steel:
55 0.187 §% 0.625 inch:-------------------------------------------------- 2 . . . . . . . . . .
56 0.187 inch (#) by 1inch....:--------------------------------------------- 1 2
57 0.190 inch (No. {} by 1.375 inches. ...------------------------ - - - - - - - - - - - 5 |----------
58 0.191 inch (No. 10) by 1.5 inches. . . . . . . . . . . . . . . . . . -- - - - - - - - - - - - - - - - - - - - - 3 1. ---------
59 0.191 inch (No. 10) by 1.875 inches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ----- 4 3.
60 0.375 inch by 3.5 inches. ------------------------------------------------- 1 1
61 || Pins, taper, 0.208 inch by 1.5 inches------. . . . . . . . . . . . . . . . . . . . . --------------- 1 1
62 | Plate, anchor---------------------------------------------------------------- 1 ----------
63 | Plate, name... --------------------------------------------------------------- 1 ----------
64 || Plug, brake, lever----------------------------------------------------------. 1 ----------
65 | Rack, brake segment... ----------------------------------------------------- 1 ----------
66 | Rails, back------------------------------------------------------------------ 2 ----------
67 | Rails, end...---------------------------------------------------------------- 4 ----------
68 Rails, front------------------------------------------------------------------ 2 ----------
Rivets, countersunk head:
69 0.125 inch by 0.687 inch (+4). . . . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - 12
70 1.40 (#) by 0.25 inch ---------------------------------------------------- 4 --------- *-
71 0.25 inch by 0.625 inch --------------------------------------------------- 4 --------- *
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
119
List of parts of Amtiaircraft Machine Gun Mount, Cygnet type, etc.—Continued.
AMMUNITION TRAILER PARTS-Continued.
r
No. Name of part. ; º; Spares.
7? | Rod, brake. . . . . . . . .--------------------------------------------------------. 1 . . . . . . . . . .
73 || Rod, brake connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ! --- - - - - - - - - - - - - - - - - - 1 ----------
74 Screws, ſlathead, wood, 0.75 inch (No. 10). . . . . . . . . . . . . . . . . . . . . . . . .- - - - - - - - - - 48 12
75 Screws, hexagonal head cap, 0.312 inch (*) by 0.625 inch, U. S. standard
thread, 24 per inch. . . . . . . . . . . . . . . . . . ,- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2 l
Screws, round head:
76 0.19 inch (No. 10) by 0.375 inch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.
77 0.25 inch by 0.375 inch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ----------
78 Screws, round head, steel, 0.625 inch (No. 5). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1
79 || Spindle, axle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
80 | Stiles------------------------------------------------------------------------ 11 - - - - - - - - - -
81 | Stiles, end corner. ---------------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 . . . . . . . . . .
82 | Strap, Pun------------------------------------------------------------------- 2 . . . . . . . . . .
83 | Strap, gun ------------------------------------------------------------------ 2 ----------
84 Strip, bottom (back). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
85 | Strip, bottom (front). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ! ----------
83 | Strip, guide (C"). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
87 || Spring, brake lever . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.
88 | Stud, brake lever. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.
89 Tube, anchor leg. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ! ----------
90 Tube, axle. . . . . . . .--------------------------------------------------------. ! ----------
91 | Tube (inner), brake lever. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ! 1 ----------
92 | Tube (outer), brake lever... . . . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 ----------
93 l Tube, frame handle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
94 | Tube (center), frame. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
95 Tube (Side), frame----------------------------------------------------------- 2 . . . . . . . . . .
96 Tube, lunette- - - -----------------------------------------------------------. ! ----------
Washers: t
97 0.25-inch----------------------------------------------------------------- | 4 1.
98 0.375-inch. . . . . . . . . . . . . . . . . . . . . ------------------------------------------- ! 9 3
Washers, lock:
99 0.312-inch (*). ---------------------------------------------------------- 12 3
100 0.375-inch---------------------------------------------------------------- 16 4
Wheels, complete.----------------------------------------------------------. | 2 |----------
Each consisting of:
13, 0.375-inch balls, steel.
13, Ö437-inch (;) baſis, steel.
1 bail Cup º: s
1 ball cup (outer).
1 brake drum.
1 COne §:}
1 cone (outer). *
1 dust guard. $
1 dust washer (ſelt).
1 hub.
1 hub cap.
1 retainer ring (inner).
1 retainer ring (outer).
5, 0.25-inch by 0.5-inch rivets (buttonhead).
1 rim (tire), Mott Wheel Works, or equal.
40 spokes, wire, with nipples, 0.134 inch diameter by 12 inches.
1 º (pneumatic), 28 inches by 3 inches, complete, including inner tube,
valve, etc. - -
To be furnished in addition to the above equipment:
101 Inner tube (28 inches by 3 inches). ----------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l
102 Blow-out patch (inside) for 28-inch by 3-inch tire . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
103 Blow-out patch (outside) for 28-inch by 3-inch tire. . . . . . . . . . . . . . . . . . . . . . . 1 ----------
104 Cone (outer)------------------------------------- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1
105 Dust washer (ſelt).---------------------------------------------------------------- 1
106 Hub cap----------------------------------------------------------------|---------- 1
107 Yoke, brake-adjusting. -------------------------------------------------- 2 ----------
(SECHLER TRAILER).
(Plates 53 and 54.)
ANTIAIRCRAFT MACHINE GUN TRAILER, MODEL OF 1918
In order to provide for the defense against aircraft of Field Artil-
lery batteries and furnish satisfactory means of transportation for
the necessary material, which weighs approximately a ton and one-
half, a wheeled trailer of heavy wagon type was adopted, the Anti-
aircraft Machine Gun Trailer, Model 1918, known as the Sechler type.
120 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
This trailer consists of the Antiaircraft Machine Gun Trailer body,
Model 1918, mounted on the 14-Ton Trailer chassis, Model 1917. It
carries two machine guns, with mounts for each, and the necessary
spare parts, accessories, and ammunition. Various tools, pick, shovel,
ax, hatchet, etc., are also carried. -
The trailer may be equipped with two Antiaircraft Machine Gun
Mounts, Cygnet type, or two Antiaircraft Machine Gun Tripods,
Model of 1918, or one of each type. One mount, usually the Cygnet, is
located on the rear of the trailer, and the other, usually the high tri-
pod, on the front end. The tripod feet are held from spreading by
steel plate supports on the floor of the trailer, and the tripod may be
fastened down to floor by a turnbuckle rod on same being hitched to
lower end of tripod center post, .
Descriptions of the mounts and instructions regarding their use
may be found in the preceding pages of this chapter. For full par-
ticulars re the trailer itself refer to handbook No. 1980, “Antiaircraft
Machine Gun Trailer, Model 1918.”
Adapters for the machine guns to be used on the trailer are fur-
nished with the mounts. The Browning Machine Gun, Model of 1917,
is intended to be used on this trailer; but any of the other machine
guns provided with antiaircraft adapters for the mounts, viz, the
Vickers Machine Gun, Model of 1915, usable with the Browning
Adapter; the Marlin Aircraft Machine Gun, Model of 1917; the Mar-
lin Tank Machine Gun, Model of 1918; the Hotchkiss Machine Gun,
Model of 1914; the Lewis Machine Gun, Model of 1917; or the Brown-
ing Automatic Rifle, Model of 1918, could be mounted on the trailer if
the Browning Machine Gun were not available.
The spare parts chest located in the center of the trailer body con-
tains spare parts for the two Browning guns designed to be carried,
and on each side of the spare parts chest, running crosswise of the
body, are two gun chests designed to house the guns when not
mounted. The ammunition boxes are placed under the spare parts
and gun chests. Water boxes are carried in strap steel retainers on
the floor of the trailer.
The trailer body is made of oak and substantially braced by corner
angles and side braces. The floor is of oak, bolted to a heavy longi-
tudinal oak sill which rests on the channel steel frame of the trailer
chassis, which is of standard design, with conventional side channel
frame, angular cross members, Šemielliptic springs, and standard
drawbar. Steering is accomplished in the usual manner, the draw-
bar transmitting the motion through a drag link to the tie rod,
thence to the wheel spindles. Both front and rear springs are fixed
at their front ends, being free to move at the other end. Lubrication
of the trailer parts is furnished by grease cups placed at the wear-
ing points, the ends of each spring bolt, each of the front wheel
spindles, and the two ends of the drag link.
§
PLATE 53
ANTIAIRCRAFT MACHINE GUN TRAILER, MoDEL of 1918 (sechLER TYPE), WITH cygne T Mount AND ANTIAIRCRAFT MA-
CHINE GUN TRIPOD, MODEL OF 1918, COMPLETE VIEW, RIGHT SIDE.

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ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 123
A standard coupling is fastened to the rear end of the chassis
frame and is used for attaching other trailers or vehicles.
No special instructions are necessary for the use of the trailer, ex-
cepting those regarding use of the machine-gun mounts.
Summary of details of trailer body and chassis.
Carrying capacity –––––-------------------------------------- tonS__ 1%
Wheel base------------------------------------------------ in Ches__ 77
Width of tread of Wheels------------------------------------- (10–––– 56
Frame width, Over all--------------------------------------- do–––– 37
Frame length, over all--------------------------------------- do---- 121.5
Weight of chassis, unequipped----------------------------- pounds—— 1,495
Weight Of chassis, equipped –––––––––––––– do———— 1, 755
Height from ground to front axle, lowest point______________ inches—— 12. 5
Height from ground to rear axle, lowest point________________ do–––– 15
Height from ground to floor boards, empty_____________________ do–––– 33
Height from ground to coupler center line_-___________________ do–––– 29
Springs, Width, Center to Center------------------------------ do–––– 35. 5
Over-all width, Widest point---------------------------------- do---- 68. 5
Body width, over all----------------------------------------- do–––– 47. 5
Body length, over all----------------------------------------- do---- 123. 5
Body depth, Over all------------------- –––––––––––––––––––––– do–––– 12
Wheel diameter --------------------------------------------- do–––– 32
Tire size---------------------------------------------------- (lo___. 32 by 3
Wheel type, wood, Artillery.
Wheel bearings, No. 307 and No. 308, taper roller, Bock.
Front frame cross member, 2.5'' by 1.5'' by 0.25'' by 36.5'', angle, steel.
Center frame cross member, 2.5'' by 1.5'' by 0.25'' by 36.5’’, angle, steel.
Rear frame cross member, 3'' by 2'' by 0.312'' by 36.5’’, angle, steel.
Side frame member, 3'' by 4 (lb.-ft.), channel, steel.
Floor, oak.
Equipment, etc., see Handbook No. 1980, Anti-Aircraft Machine Gun Trailer,
MOClel 1918.
ADAPTERS FOR MACHINE GUNS USED ON ANTIAIRCRAFT
MOUNTS.
BROWNING AND WICKERS ADAPTER.
(Plates 55, 56, 36, 38, 41, 42, 54.)
This adapter will take either the Browning Machine Gun, Model
of 1917, or the Vickers Machine Gun, Model of 1915.
It fits on the Antiaircraft Improvised Post Mount, the Antiaircraft
Machine Gun Mount, Model of 1918, and the Antiaircraft Machine
Gun Mount, Cygnet type, which is used on both the Cygnet trailer
and Sechler trailer. -
The adapter consists of a steel frame with side holes and chained
cross pins for attachment to machine gun and mount head. It is
made of two, parallel, pressed steel side plates joined by a round
steel cross bar at one end and a pressed steel connecting plate at the
other end.
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124
PLATE 55.
§
ADAPTER, ANTIAIRCRAFT, BROWNING AND VICKERS, FOR USING BROWNING MACHINE
GUN, MoDEL of 1917, OR VICKERS MACHINE GUN, MODEL OF 1915, on ANTAIR-
CRAFT MoUNTS. ComPLETE WITH VICKERS AMMUNITION BOX CONTAINER OR
BASKET AS ISSUED FOR VICKERS GUN.

126 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
On the left side of the adapter is riveted to the side plate a clip
which engages the Browning Ammunition Box, by means of side
grooves near the forward end of the box. On the right side is
riveted a clip which receives a steel Container, or basket, shown at
the right of plate 56, that holds the Vickers Ammunition Box, neces-
Sary because that box has no means of direct attachment to the
adapter. The Vickers box is set in the container by lifting the box
cover, hooking the top front edge of the box under the bent down
flange along the container top, and depressing the box until the
two side springs of the container grip over top sides of box. This
basket attachment is used only with the Wickers Machine Gun.
List of parts, Browning and 'Vickers Adapter.

*
.* Number
No Part. required. Spares
1 | Adapter end---------------------- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 |---------.
2 || Adapter handle º & s sº sº is sº * * * * * is s ºs e s is ºr sº as e º as s sº e s & º ºs º ºs ºs e º sº sº is e º sº gº is sº a se sº * * * * * * * | 1 |----------
3 || Adapter handle (rear). . . . . . . .* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - p = ~ * * * * * * * * * * * * * 1 ----------
4 Adapter separator----------------------------------------------------------- 1 ----------
5 | Adapter side (left)-------------------------------------------------------- - - - , 1 ----------
6 || Adapter side (right). . . . . . . . . . . . . . . . . . . . . . . . . .** * * * * * * * * * * * * * * * * *-------------|' 1 ----------
7 | Ammunition basket holder.................................... ar e = * * * * * * * * * -- 1 ----------
8 Ammunition box holder----------------------------------------------------- 1 |----------
9 | Bushing §. * * * * * * * * * * * * * * * * * * * * * * * *s ºr gº is is sº * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * - 1 ----------
10 | Bushing (adapter)--------------------------------------------- -------------- | 1 |----------
11 | Bushing (adapter handle, rear). --------------------------------------------- 1 ----------
12 #º:::::::::::::::::::::::::::::::::::::::* & s gº tº as sº 1 ----------
13 | Bushing (pivot lever handle). . . . . . .- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 ----------
14 | Bushing (pivot lever handle). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -- - - - - - - - - - - - - - - * 1 ----------
15 | Chain, complete------------------------------------------------------------- 1 ----------
;
3.5 ounce Steel chain, 6 inches long-- - - - - - - - - - - - - - - - - ... - - - - - - - - - - - - - - - 1
0.125-inch by 0.812-inch Steel ring...................................... 1
0.125-inch by 0.375-inch steel rings... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Chain rivet----------------------------------------------------------- 1
3.5-ounce Steel chain, 5 inches long------------------------------------ 1.
0.125-inch by 0.812-inch (+4) Steel ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
0.125-inch by 0.375-inch steel rings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Chain rivet------------------------------------------------ * - - - - - - - - - - 1
17 | Locking screw--------------------------------------------------------------- 1 ----------
18 Looking screw--------------------------------------------------------------- 1 ----------
19| Locking screw--------------------------------------------------------------- 1 ----------
20 ! Pivot lever handle. . . . . . . . . . . . . . . . . . . . . . * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 1 ----------
21 Rivets, buttonhead, 0.187-inch by 0.75-inch...... . . . . . . . . . . . . . . . . . . . . - - - - - - - - i 6 ----------
22 Rivets, buttonhead, 0.25-inch by 0.875-inch......... . . . . . . . . • - - - - - - - - - - - - - - - - : 4 |----------
23 Rivets, countersunk head, 0.25-inch by 0.625-inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 ----------
24 Cº.; Belt Guide, complete, for use on Browning or Vickers ammuni-
ion box-------------------------------------------------- • * * * * * * * * ~ * * * * * * * 1 |----------
25 || Ammunition Box Container or basket, complete for use with Vickers am-
munition box. Only included in issue for Vickers machine gun use. . . . . . 1 ----------
MARLIN AIRCRAFT AND MARLIN TANK ADAPTER.
(Plates 57, 43, 49, 54.)
This adapter will take either the Marlin Aircraft Machine Gun,
Model of 1917, the Marlin Tank Machine Gun, Model of 1918, or the
Colt Machine Gun.
It fits on the Antiaircraft Improvised Post Mount, the Antiair-
craft Machine Gun Tripod, Model of 1918, and the Antiaircraft Ma-
chine Gun Mount, Cygnet type, which is used on both the Cygnet
trailer and Sechler trailer. *
The adapter consists of a steel or malleable-iron casting designed
to take either one of the Marlin Machine Guns, aircraft or tank, or
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128
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 129
the Colt Machine Gun. It is provided with chained handle pins and
lugs with holes whereby its upper side is attached to the gun and its
lower side to the mount head. It has an adjusting Screw which
may be used to fit the adapter tightly to the gun. Only the Brown-
ing Ammunition Box is used with this adapter, the attaching clip
for same being embodied in the casting.
List of parts, Marlin Adapter.

No. Part. ; Spares.
1 | Adapter.......-------------------------------------------------------------- 1 ----------
2 Handle pin (front)----------------------------------------------------------- 1 ----------
3 | Handle pin (rear).----------------------------------------------------------- 1 ----------
4 | Chain (handle pin, front), complete. . . . . . . . . . . . . . . . . . . . . . . . . . . . -------------- 1 ----------
Including:
3.5-ounce steel chain, 6 inches long, 1.
0.125-inch by 0.812-inch steel ring, 1.
No. 10–32 round-head machine screw, 1. *
5 | Chain (handle pin, rear), complete. . . . . . . . . . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - 1 ----------
Including: . .
3.5-ounce steel chain, 6 inches long, 1.
0.125-inch by 0.812-inch steel ring, 1.
No. 10–32 round-head machine screw, 1.
6 | Locking screws-------------------------------------------------------------- 2 ----------
7 | Adjusting Screw------------------------------------------------------------- 1 ----------
8 || Nut (adjusting screw), 0.625-inch by 0.375-inch thick. . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
9 || And 1 Cartridge Belt Guide, complete, for use on Browning Ammunition
Box. (For list of parts see p. 159.)
NOTE.-The handle pin, rear, is used only with the Cygnet Mount, being locked in adapter and left there
when gun is used on the improvised Post Mount or Antiaircraft Machine-Gun Tripod, Model of 1918.
LEWIS ADAPTER.
(Plates 58, 36, 44, 47.)
This adapter takes the Lewis Machine Gun, Model of 1917.
It fits on the Antiaircraft Improvised Post Mount, the Antiaircraft
Machine Gun Mount, Model of 1918, and the Antiaircraft Machine
Gun Mount, Cygnet type, which is used on both the Cygnet trailer and
Sechler trailer. .
The adapter consists of an oblong pressed steel base with a con-
tinuous-edge flange that recesses its under side. Mounted on the base
are two circular steel band clamps, hinged in half at the left side and
eccentric-pin-locked at the right side, which embrace the radiator of
the Lewis gun. The gun is mounted on the adapter by placing it
upon the lower half of the opened clamps, the center adapter clamp
between the two rear bands of the radiator and the end adapter clamp
placed forward on the radiator, adjoining the antiaircraft sight-band
location; then fitting down about the radiator the upper half of the
clamps, until they are lockingly engaged with the lower half clamps,
and turning the handle of the eccentric pin to lock. The adapter is
attached to the gun mount head by means of side flange holes, the
center one for pivot pin and the rear one, which is provided with a
chained pin, for attachment to gun arm elevating screw head, where
there is one on mount used. The gun clamps are designed to fold
down on the adapter base when not in use. *
As
130 ANTIAIRCRAFT MATERIEL FOR MACHINE GUINS.
List of parts Lewis Adapter.
y Number
NO Part. required. Sparos.
1 Adaptor body--------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. . . . . . . . . .
2 Adapter bushing (center)............................................ * - - - - - - - 2 |. . . . . . . . . .
3 Adapter bushing (end). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
4 || Adapter separator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - . . . . . . . . .
5 Gun clamp §: * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * s = e º 1 |. . . . . . . . . .
6 Gun Clamp (upper)--. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - . . . . . . . . .
7 | Gun clamp (lower). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - . . . . . . . . .
8 Gun clamp (upper)----. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - . . . . . . . . .
9| Gun clamp handle.-------.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 |. . . . . . . . . .
10 | Gun clamp handle pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. l. . . . . . . . . .
11 || Gun clamp handle Spring...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
12 Gun clamp hinge pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
13 | Gun clamp holder (end). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 |. . . . . . . . . .
14 || Gun clamp holder (Center)... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 | . . . . . . . . . .
15 Gun clamp holder pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1. . . . . . . . . .
16 || Gun clamp holder washer.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
17 | Locking screw (handle pin, rear)..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - . . . . . . . . .
18 Nuts, crown, 0.5-inch, U. S. standard thread, 20 per inch. . . . . . . . . . . . . . . . . . . . 2 |. . . . . . . . . .
19 || Pins, split, 0.125 inch by 1.25 inch............................................ 2 |. . . . . . . . . .
20 | Handle pin (rear), complete with chain, ring, and round-head machinescrew
(used only with Cygnet Mount). Śams' as in Marlin Adapter list of
parts, page 130... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ! . . . . . . . . . .
HOTCHKISS ADAPTER.
(Plates 59, 39, 45, 50.)
This adapter takes the Hotchkiss Machine Gun, Model of 1914.
It fits on the Antiaircraft Improvised Post Mount, the Antiaircraft
Machine Gun Mount, Model of 1918, and the Antiaircraft Machine
Gun Mount, Cygnet type, which is used on both the Cygnet trailer
and
Sechler trailer.
This adapter consists of a steel casting shaped like a U set upright
across one end of a flat shank.
The gun lugs provide a trunnion
bearing for the gun, which is secured in place by two bearing caps
and winged nut Swing bolts, the rear end of the adapter attaching
to the gun by means of the elevating screw mounting pin, passed
through a lug on upper rear end of adapter. The under side of the
adapter has pivotal and rear lugs for its attachment to gun mount
head, a chained pin being attached to rear lugs for use when re-
quired by mount used.
JMist of parts, Hotchlciss Adapter.
|
ºr Number
No. Part. required. Spares.
1 | Adapter frame... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 | . . . . . . . . . .
2 | Locking screw (handle pin, rear)..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 | . . . . . . . . . .
3 || Pins (trunnion cap, 2; swing bolt, 2)... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - . . . . . . . . .
4 | Swing bolts... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - . . . . . . . . .
5 Thumb nuts... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 |. . . . . . . . . .
6 Trunnion caps... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
7 | Handle pin **) complete, with chain, ring, and round-head machinescrew
(used ºy with Cygnet Mount). Same as in Marlin Adapter list of parts,
page 130. . . . . . . . . . . . . . . . . . . , e = <s s as is es e s is as s as ºs e s = gº tº es sº is is gº sº e º sº tº s ºs e º is tº sº º tº º sº tº tº e º ºn s = * 1 - . . . . . . . . .
:
-
PLATE 59.
22 ||
ADAPTER, ANTIAIRCRAFT, HoTchkiss, FoR Us NG HoTCHKISS MACHINE GUN, MODEL OF 1914, ON
ANTIAIRCRAFT MOUNTS.


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132
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 133
BROWNING AUTOMATIC RIFLE ADAPTER.
(Plates 60, 37.)
This adapter takes the Browning Automatic Rifle, Model of 1918.
It fits on the Antiaircraft Improvised Post Mount, the Antiaircraft
Machine Gun Mount, Model of 1918, and the Antiaircraft Machine
Gun Mount, Cygnet type, which is used on both the Cygnet trailer
and Sechler trailer.
This adapter is approximately of H form and consists of a malle-
able iron or steel casting comprising the two lower wings and one
upper wing, or clamp jaw, the upper end of which houses the pivot
end of a Swing bolt that carries on its threaded free end a washer and
winged clamp nut. The other upper wing, or clamp jaw, is a sep-
arate casting that is hinged at its bottom to the main casting and has
a Swing-bolt slot in its upper center. Clamp jaw sides and bottom
have riveted to their inner surface a lining of thick, roughened-face
leather. The lower wings of the adapter have transverse holes whereby
the adapter is attached by pivot pin to the gun mount head. This
adapter has only one point of attachment to the mount. When used
On mounts having an elevation adjusting screw, the screw should be
turned to its lowest position, and the worm adjustment locked. The
Automatic Rifle should always be placed in the adapter clamp with
the Swing-bolt hinge at the left side, the loose clamp jaw at the right
side, and the fore end of the forearm escutcheon, or chequered hand-
grip, in line with the outer edge of the clamp jaws; this gripping
position of the clamp being necessary for the reason that the gun
stock is solid at this point but hollow under the rear portion of the
forearm escutcheon. In mounting the rifle it is set in the clamp as
directed and the swing bolt turned down across the barrel top into
its slot in the loose clamp jaw, the winged nut being then screwed
tightly against washer and clamp jaw until the rifle is securely
clamped in position.
List of parts, Browning Automatic Rifle Adapter.
* Number º
NO Part. required. Spares.
1 | Adapter clamp. -----------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 |----------
2 | Adapter clamp bolt----------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 |----------
3 Adapter frame-----------------------------------------. . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .
4 | Clamp pins.------------------------------------------------------. . . . . . . . . . . 2 1
5 | Leather strip, 2 inches by 0.187 inch by 2.75 inches.... . . . . . . . . . . . . . . . . . . . . . . . 1 - - - - - - - - - -
6 | Leather strip, 2 inches by 0.187 inch by 5.125 inches..... . . . . . . . . . . . . . . . . . . . . . . 1 ----------
7 Rivets, belt, No. 10, by 0.5 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 . . . . . . . . . .
8 || Pins, split, 0.093 inch by 0.5 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2
9 | Washer, 0.375 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
10 | Wing nut, commercial, 0.375 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l 1.
134 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
ANTIAIRCRAFT MACHINE GUN LIGHT FOLDING STAND
(BRITISH).
(Plate 61.)
The British have developed a very light folding tripod for use
with the Lewis Machine Gun by mobile units. It consists of a tubu-
lar center post with a swiveling, offset, steel rod mounting pin set
in its top, mounted in a basic tripod through sliding collars which
form the tripod head and tripod leg brace yokes respectively. The
center post is held at various heights by a chain attached cross pin
inserted in One of a series of holes through the post. A cap plug in
the bottom of the tubular post prevents its withdrawal through the
tripod collars and also holds a slingstrap staple. The tripod feet
are flat extensions of the legs with a steel stud on the under side to
engage the ground. When the center post stop pin is withdrawn,
the tripod legs may be folded up on the post much as an umbrella
closes. A leather slingstrap extends from the bottom ring to a wire
staple on the upper part of the center post, for carrying the stand.
A steel clamp band, pivoted by lugs in its bracket lower Section to
the top of a short piece of light steel tube, is attached to the Lewis
gun between the two rear bands of its radiator by means of a swing
bolt looped in one end of the clamp band, which engages the slotted
flange in the other end and is tightened on the radiator by a winged
clamping nut. The gun is mounted on the tripod head pin at will
by simply setting on it the light hinged tube of the clamp band.
This stand can easily be redesigned for use with the Browning
Automatic Rifle as well as the Lewis Machine Gun and this develop-
ment will probably follow.
FLATE 61.
ANTIAIRCRAFT LIGHT FOLDING STAND, BRITISH, AS USED
WITH LEWIS MACHINE GUN WITH TRENCH SIGHT.



PLATE 62.
SHOULDER STOCK FOR BROWN ING MACHINE GUN, MODEL OF 1917.
136

CHAPTER VII.
ANTIAIRCRAFT MACHINE-GUN STOCKS.
INTRODUCTION.
Because antiaircraft machine-gun mounts, with the exception of
the Cygnet mount, do not hold the gun fixedly, simply affording a
pivotal support on which the gun may be swung horizontally through
a complete circle, at any angle of fire, from horizontal to vertical, it
was found desirable that means should be provided for steadying
antiaircraft machine guns while firing. The shoulder stock was
designed to meet this want. It allows the gun to be steadied by the
gunner's shoulder and materially enhances the accuracy of his fire.
These stocks are simple and attached by some convenient means to
each type of machine gun requiring same, without alteration in any
way of the gun as issued. -
Stocks are provided for the following machine guns:
Browning Machine Gun, Model of 1917 (Browning Machine Gun
Stock).
Vickers Machine Gun, Model of 1915 (Vickers Machine Gun
Stock). t
Marlin Aircraft Machine Gun, Model of 1917, and Marlin Tank
Machine Gun, Model of 1918 (Marlin Machine Gun Stock).
Hotchkiss Machine Gun, Model of 1914 (Hotchkiss Machine Gun
Stock).
The Lewis Machine Gun and the Browning Automatic Rifle re-
quire no stock attachment, being made with stocks.
On the following pages will be found descriptions, illustrations,
and directions for attachment and use of the shoulder stocks for the
various guns. Also lists of parts.
ANTIAIRCRAFT STOCK, FOR BROWNING MACHINE GUN, MODEL OF 1917.
(Emergency Shoulder Rest for Browning Machine Gun, Mark I.)
(Plates 62, 1, 36, 41.)
1. Description.—The shoulder stock used on the Browning Machine
Gun, Model of 1917, for antiaircraft fire is the same stock, or shoulder
rest, designed for field use with the Browning Tank Machine Gun,
Model of 1919. The stock consists of a piece of seamless steel tubing,
137
138 ANTIAIRCRAFT MATERIEL FOR MACHINE GUNS.
of inner diameter to fit over the cylindrical head of the pistol grip on
the Browning gun, with a transversely corrugated, pressed steel shoul-
der piece welded, by means of an intermediate flange, across its outer
end, forming a T. The front end of the stock has a slot in its under
side to permit passage of the neck of the pistol grip, and a steel
band clamp cuff welded around the upper two-thirds of its circum-
ference. A curved, swinging clamp bolt, or eyebolt, has its eyeleted
butt hinged in a slotted loop in one end of the cuff and a winged
clamping nut mounted on its threaded free end; the bolt and wing
nut engaging a slotted lug on the opposite end of the clamp cuff
to clamp the stock rigidly in place on the gun.
2. Directions for attaching and use.—Open the clamp, if closed, by
unscrewing the wing nut sufficiently to allow the eyebolt to be swung
outward; slide the clamp end of the stock over the head of the
pistol grip of the gun until the clamp is beyond and clear of the
forward side of the pistol grip. Then swing the bolt into place in
the slot of the lug on the opposite end of the clamp cuff and tighten
the wing nut down on the lug until the stock is rigidly held in place.
To detach the stock, reverse the attaching operations.
The gunner presses his shoulder firmly against the shoulder piece,
using the stock both to support and maneuver the gun.
JMist of parts Browning Machine Gun Stock.

No. Part, j Spares.
1 | Shoulder piece. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 |. . . . . . . . . .
2 | Tube flange. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 |----------
3 ube. -- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
4 Clamp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ! . . . . . . . . . .
5 | Eyebolt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. . . . . . . . . .
6 Rivet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 |. . . . . . . . . .
7 | Wing nut. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 |. . . . . . . . . .
ANTIAIRCRAFT STOCK, FOR VICKERS MACHINE GUN, MODEL OF 1915.
(Plates 63, 42.)
1. Description.—The shoulder stock for the Wickers Machine Gun
consists of a T section steel arm having a curved flat steel shoulder
piece welded across one end and a half-hinge bearing, for gun at-
tachment, bolted to the T shank at the other end. Adjoining the
gun bearing and 'slidably riding on top of the T stock arm, to which
it is clampable by a transverse set screw, is a gun rear engaging
clamp piece, or catch. This sliding catch has its forward end forked
and each fork horizontally slotted to engage the plate lower arms of
the twin grip handles on the Vickers machine gun.
2. Directions for attaching and use.—Place the attaching pin
lug on the front end of the adapter between and in hole alignment
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140
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 141
with the rear mounting pin lugs on the under side of the Vickers
gun. Insert the rear gun pin and turn to locked position. Place
the sliding clamp catch far enough back on the stock arm to clear
the handle grips of the gun. Hold the stock arm top surface flat
against the under side of the gun and slide the clamp catch forward
until the slots in its forked front end engage the lower arms of the
handle grips to right and left. Press the catch firmly against the
handle base and clamp the catch rigidly to the stock by tightening
the clamp or adjusting screw by means of its head at the right-hand
side.
To detach the stock, reverse the attaching operations.
The gunner presses his shoulder firmly against the shoulder piece,
using the stock both to support the gun and maneuver it.
List of parts, Vickers Machine Gum Stock.
Number
NO Part. required. Spares.
1 | Arm, stock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - - - - - - - - - - - - - - - - - - - - - - - - 1 ----------
2 | Bolts, 0.250 inch hy 1.25 inches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ----------
3 Catch, sliding. ------------------------------------------------------ - - - - - - - - 1 - - - - ------
4 | Lug, attaching. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
5 | Nuts, 0.25 inch crown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
6 Plate, shoulder.----------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ----------
7 Screw, adjusting. -----------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - . . . . . . . . .
8 || Split pins, 0.062 inch by 0.75 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
9 || Rivets, buttonhead, 0.125 inch by 0.625 inch..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 ----------
ANTIAIRCRAFT STOCK, FOR MARLIN AIRCRAFT MACHINE GUN, MoDEL OF 1917,
AND MARLIN TANK MACHINE GUN, MODEL OF 1918.
(Plates 64, 43, 49, 54.)
1. Description.—The shoulder stock designed for use on either one
of the above machine guns consists simply of an arm of T section steel
to one end of which is riveted a cast shoulder plate. Four holes
in the flange of the T bar at the forward end of the stock provide for
attachment to the gun, by means of screws.
2. Directions for attaching and use.—Remove the rear pin mount-
ing bracket (elevation adjusting screw bracket) from the gun by
removing the four machine screws attaching same. Attach the
shoulder stock to the gun by means of these four screws, the screw
holes in the stock coinciding with the screw holes in the under side
of the gun. •
To detach the stock, reverse the foregoing operations.
In use the gunner presses his shoulder firmly against the shoulder
plate, using the stock both to support and maneuver the gun.
142 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNs.
List of parts, Marlin Machine Gun Stock.

Numbor
NO. Part. - required. Spares
1 | Arm, stock, complete..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • a s e a s s as s - a - 1 |. . . . . . . . -
ncluding— - -
Plate, shoulder--------..................... . . . . . . . . . . . . . . . . . . . . . § a * * * * * * * * *
Rivets, buttonhead, 0.187 inch by 0.75 inch . . . . . . . . . . . . . . . . . . . . . . 4) | |----------
2 | Lock Washers, 0.25 inch, standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - . . . . . . . . .
3 Screws, attaching. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 |. . . . . . . . . .
ANTIAIRCRAFT STOCK, FOR HOTCHKISS MACHINE GUN, MODEL OF 1914.
(Plates 65, 39, 45, 50.)
1. Description.—The shoulder stock for the Hotchkiss Machine Gun
is copied from the French design. It consists of an arm section of
flat steel bar upcurved at its rear end and riveted to a curved shoulder
plate, and riveted at its front end into a channel steel arm extension
which is stepped upward at its forward terminus and there riveted
into the bottom of a U-shaped cross piece with upstanding side flanges
which bear a transverse attaching bolt; the left-hand flange being
provided with a vertical wing designed to mount the Peycru anti-
aircraft sight. Set in the bottom of the stock arm flanged section is
a headless adjusting screw, designed to press against the gun bottom,
if necessary, to make the stock fit rigidly on the gun.
2. Directions for attaching and use.—Remove the breech cover pin
of the Hotchkiss gun. Take the attaching bolt from the stock
flanges. Hold the breech cover in place and slide the stock flanges up
over the gun breech sides from below until the flange bolt holes
register with the cover pin hole of the gun. Insert the stock attach-
ing bolt, from the left side, and screw on the handled nut, washer
placed underneath, until the stock is firmly mounted. If there is any
vertical play, tighten the headless adjusting screw in stock against
gun bottom.
To detach the stock, reverse the attaching operations.
In use the gunner presses his shoulder firmly against the shoulder
plate, using the stock to support and maneuver the gun.
List of parts, Hotchlciss Machine Gun Stock.
NO. Part. . Spares
1 | Attaching bolt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - 1 - . . . . . . . . .
2 || Attaching-bolt nut. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. . . . . . . . .
3 | Shoulder plate. -------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 |----------
4 || Sight bracket (flange piece). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 |. . . . . . . . . .
5 | Stock arm ---------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . | | . . . . . . . . . .
6 | Stock-arm bar. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. . . . . . . . . .
7 | Set Screw-----------------------. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ! . . . . . . . . . .
8 || Rivets, buttonhead, 0.187 inch by 0.562 inch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .
9 || Rivets, buttonhead, 0.25 inch by 0.875 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. . . . . . . . . .
10 Rivets, buttonhead, 0.187 inch by 0.75 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. . . . . . . . . .
11 | Washer, 0.375 inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ! ----------
ºf 161 - O TE GO W 'N m º ENI HOW W SSIX HOLOH BOB » OOLS 83071 fıOHS
_
ºggȚElvina
143
152535–20–10


PLATE 66.
MMM
- -
------- --- : --- ---
-º-º-º-º: - º: -
--- |
-
B. Rownwind
Tº ELT
c O LT
13 ELT
(haan-1 N )
- v c ºxE RS
–21% º – BELY
SECTIONS SHOW ING LEADING ENDS OF BROWN ING CARTRIDGE BELT, USED
WITH BROWN ING MACHINE GUN, COLT CARTRIDGE BELT, USED WITH MAR-
LIN MACHINE GUNS, AND VICKERS CARTRIDGE BELT, USED WITH VICKERS
MACH | NE GUN,





144
CHAPTER VIII.
ACCESSORIES.
The machine gun and automatic rifle accessories used in antiair-
craft work are the same as those issued for ordinary field Service,
namely: Cartridge belts, belt-filling machines, ammunition boxes,
water boxes for water-cooled guns, extra magazines, etc., with the
addition of a cartridge-belt guide to improve the feeding of belt-fed
machine guns at high angles of fire; a stadia range indicator (fully
described in Chapter V); and eyeglasses with Fieuzal lenses—and the
substitution of a 40-round magazine for the 20-round one usually
employed with the Browning Automatic Rifle. A special carrying
pouch is, of course, required with the 40-round magazine. -
CARTRIDGE BELTS.
(Plates 66, 67.)
Ammunition belts are important considerations in antiaircraft
work. As stated previously, in Chapter I, paragraph 11, they should
contain a suitable assortment of tracer, incendiary, and armor-pierc-
ing and ordinary cartridges, and must feed freely into the machine
gun at any angle of fire. The belt itself, which is made to hold 250
or 300 cartridges, consists of two strips of suitable fabric, linen, sea-
island cotton, or reinforced paper, from 1% to 13 inches wide, which
is formed into a series of cartridge loops, or pockets, by interweaving,
wire Stitching, or the riveting together of opposed, transverse strips
Df thin metal. The feeding end of the regular belt has a metal lead-
ing tip, or tongue. *
Another form of belt which has as yet been used only by aircraft
is an expendable belt formed of individual links of thin sheet metal,
which are held together by the cartridges when inserted, as the leaves
of a hinge are held together by the pin. These metallic links are
ejected from the aircraft machine gun as the belt disintegrates in
UISO.
THE BROWNING CARTRIDGE BELT.
The Browning Cartridge Belt, plate 66, is made of strips of sea-
island cotton fabric, 14 inches wide, interwoven to form cartridge
loops, and has a metal-tipped feeding end. It is used in the Brown-
145
PLATE 67.
| |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |
||||||||||| -
| -
||||||||
SECTIONS OF DISINTEGRATING BELTS OF METALLIC LINKS, USED BY UNITED
STATES AIRCRAFT.
146



ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 147
ing Machine Gun. It holds 250 cartridges. It is identified by two
black lines woven in the fabric about one-eighth inch from and
parallel with the cartridge butt edge of the belt. It weighs, empty,
7.5 ounces.
THE COLT CARTRIDGE BELT.
The Colt Cartridge Belt, plate 66, is the same in fabric and make
as the Browning belt, but differs slightly in cartridge loop spacing
and alignment of the belt on the cartridges. It is used with the
Marlin Aircraft and Marlin Tank Machine Guns for antiaircraft
work. It is identified by a single, loop-interrupted, black line woven
in the fabric near and parallel with the cartridge butt edge of the belt.
This belt and the Browning belt are presumably interchangeable, but
in fact are not; they jam in very short time if used in the wrong gun.
THE VICKERS CARTRIDGE BELT.
The Wickers Cartridge Belt, plate 66, is made of two strips of
linen fabric, 1% inches wide, formed into loops by transverse strips
of thin metal on opposite sides, being riveted together through the
fabric. Every fourth metal clip extends to cartridge length, thus
forming a feeding guide and also indicating whether the cartridges
are properly placed in the belt. The feeding end of the belt has a
sheet-metal leading tongue. This belt holds 250 rounds. It is used
with the Vickers and Maxim Machine Guns. It weighs, empty, 24
pounds. - -
The Expendable Cartridge Belt is used only in connection with the
Expendable Ammunition Box, or container (described hereafter under
the heading of Ammunition Boxes), in which it is issued, sealed up.
It is not at present used in antiaircraft work, excepting its possible
incidental employment against very low-flying attacking planes.
This belt is made of two strips of cotton-reinforced paper, 11'ſ inches
wide, formed into cartridge loops by transverse wire stitches or clips.
It holds 300 rounds, as issued with Mark I expendable box. It is
used as yet only with the Browning Machine Gun.
BELT-LOADING MACHINES.
(Plates 68 and 69.)
These machines are used for filling machine-gun belts with car.
tridges. As their use is of importance in antiaircraft work, which
necessitates the filling of belts with a suitable assortment of special
and ordinary cartridges, the officers and men concerned should be
familiar with their construction and operation. Three types of belt
filler are issued, the Browning, Marlin-Colt, and Vickers.
PLATE 68.
-
BROWN ING BELT-LOAD ||NG MACHINE.

148
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 149
THE BROWNING BELT-LOADING MACHINE.
(Plate 68.)
This machine has a cast-iron body to which the other parts are
assembled; a cartridge guide into which the cartridges are stripped
from their clips by the act of insertion; screw holes in the base for
attaching the machine to a table or board; and a crank handle for
operating. It is simple in operation.
Two cartridges are inserted in the leading end of the belt; the belt
end inserted in the feedway, and the crank turned. As the crank
revolves, the belt is drawn through the machine by the rotation of
upper and lower sprocket wheels which engage the cartridge-filled
section of the belt. As the belt loops are moved into filling position
they are simultaneously engaged on both sides by steel needles, and
thereby held open while the feeding plunger pushes a cartridge into
place. It is used for filling the Browning Cartridge Belt.
With tools, accessories, and carrying box, the machine weighs
about 20 pounds.
THE MARLIN-COLT BELT-LOADING MACHINE.
This is practically the same as the Browning Belt-Loading Ma-
chine differing mainly in having only one upper and one lower loop-
opening needle and a longer step in advancing cartridge loops into
filling position. This machine should not be confused with the
Browning one, as they are not interchangeable and will jam in filling
wrong belts. It is used in filling the Colt Cartridge Belt, used in the
Marlin Machine Guns.
THE VICKERS BELT-LOADING MACHINE.
(Plate 69.)
This machine has a bronze body to which the other parts are
assembled; a cartridge guide into which the cartridges are fed from
their clips or packages by hand; a bracket by which the machine may
be attached to the edge of a board or table; and a crank handle for
operating. It is easily operated.
The cartridge guide being filled and the crank turned, the mechan-
ism advances the belt into position; a metal finger is thrust from one
side into the loop in place, opening same, and a cartridge pushed into
the loop from the opposite side by a feeding plunger following the
withdrawal of the opening finger. This belt-filling machine is used
for filling the Vickers Cartridge Belt.
With tools, accessories, and carrying box, the machine weighs about
22 pounds. -
AMMUNITION BOXES.
Ammunition boxes are the carrying cases or containers for
machine-gun cartridge belts. Several types have been in use from
time to time; namely, the Maxim, Vickers, and Browning boxes, of
PLATE 69.
VICKERS BELT-Loading MACHINE LOAD ING WICKERS CARTRIDGE BELT
(CARTRIDGES SHOWN ARE OLD STYLE, ROUND NOSED).

150
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNs. 151
which the latter has become the standard design. This present
standard ammunition box is made of wood; has a strongly hinged
cover with a substantial fastening clasp, and a strap handle for carry-
ing. This box contains a cartridge belt holding 250 rounds and when
empty is intended to be returned and refilled. In use it is attached
to the machine-gun mount in suitable position for the belt to be fed
into the gun. The Browning and Vickers ammunition boxes are
hereafter described.
Expendable ammunition boxes are a recent development and will
probably supersede the refillable boxes now standard. The expend-
able box is made of sheet metal, wood, or sheet metal stiffened by
wood, and of approximately the same outer dimensions as the stand-
ard box, but is not intended to be refilled. Four types have been
designed—one drum-shaped and holding a 200-round belt, the others
rectangular and holding a 300-round belt. Mark I Expendable box,
hereafter described, is considered to be the best design. These boxes
are filled at the munition factory with a loaded expendable cartridge
belt and the sheet-metal cover soft-soldered in place thereon. The
cover has a stiff wire ring looped in one end, by which it may be
grasped and stripped off when the contents of the box are required.
The wire ring may also be used to fasten down the cover temporarily
if the box is not entirely emptied. As this type of ammunition box
is hermetically sealed and its contents protected from damp, and, by
its longer belt capacity and nonreturn for refilling, effects a great
saving in transportation, it is practically certain that these advan-
tages will eventually bring the expendable ammunition container
into almost exclusive use. In this event, the cartridge belts for
antiaircraft work will have to be filled at the munition factory with
the special assortments of cartridges necessary for this purpose,
and the sealed containers for same will require special marking that
will readily identify their contents. -
THE BROWNING AMMUNITION BOX.
(Plates 70, 36, 41, 43, 46, 49, 54.)
This box, the standard type at present, is made of wood, prefer-
ably oak, and is about 4% inches by 12# inches by 7% inches in outer
dimensions. It holds a loaded 250-round cartridge belt. It weighs
when empty 5 to 6 pounds; when filled with the loaded belt, about
20 pounds. It is used with the Browning, Marlin Aircraft and Mar-
lin Tank machine guns for antiaircraft work.
The box is rectangular in shape, with the exception that the
lower front corner is cut away or beveled to permit the box to
clear the traversing dial of the gun tripod when mounted for use.
It is mounted for use by sliding the flanged head end of the box
into engagement with a shallow flanged bracket on the left-hand
PLATE 70.
AMMUNITION BOX, BROWN ING. (STANDARD WOOD EN TYPE.)
* PLATE 71.
AMMUNITION BOX, VICKERS.
152


ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNs. 153
side of the head of the gun mount, which fixes the box in proper
position for feeding the belt to the gun. -
The box has a strongly mounted lid, about 3 inch thick, which
is hinged transversely of its width, about 2 inches from the rear end,
and has inset a spring fastening clasp, releasable only by direct top
pressure, which engages a stud inset in the front face of the box.
A carrying strap of leather is mounted in a recess in the top of the
lid and held there by transverse metal pins which pass through the
lid body and end loops in the strap.
THE VICKERS AMMUNITION BOX.
(Plates 71, 38, 42, 48.)
The Vickers box is used with the Vickers and Maxim machine
guns. In general construction it is practically the same as the
Browning Ammunition Box just described. It differs mainly in being
slightly longer and heavier; fully rectangular and smooth walled.
It is 24 inches longer than the Browning box and has no corner
off nor any side grooves. It is 4% inches by 15 inches by 7% inches
in outer dimensions. It holds a 250-round Vickers Cartridge Belt
and weighs when filled about 21 pounds. For use it is placed in a
metal Container, or basket, fixed on the head of the gun mount on the
right-hand side.
THE EXPENDABLE AMMUNITION BOX, MARK I.
(Plates 72, 73, 1, 31, 33, 54.)
The Expendable box, which is filled and sealed at the munition
factory, is the same in Outer dimensions as the Browning standard
wooden box, being about 4% inches by 12% inches by 7% inches in size
and rectangular except as regards the beveled lower front corner.
For use it is attached to the gun mount in the same way as the
standard box. It holds a loaded 300-round Expendable Cartridge
Belt and weighs when empty, about 5 pounds; when filled, about 19
pounds. It is used with the Browning, Marlin Aircraft, and Marlin
Tank machine guns for antiaircraft work.
This box is formed of terneplate, a species of tinplate coated with
an alloy of tin and lead. It has paneled ends, transversely corrugated
for additional strength; flat sides with mounting grooves indented
at the head end; and a runner-edged, or channeled, top and bottom.
The sides are stiffened by a wooden board lining which is embraced
along its upper and lower edges by the sheet metal, thus forming the
longitudinal protecting ridges, or runners, which give channel form
to the top and bottom of the box. The cover is a single flat strip of
sheet metal, tapered at its front end to enloop a wire ring by which
it may be grasped for stripping off. When the box is filled at the
- PLATE 72.
AMMUNITION BOX, EXPEN DABLE, MARK I.

PLATE 73.
AMMUNITION BOX, EXPENDABLE, MARK I, ATTACHED TO HEAD OF MACHINE-
GUN TRIPO.D. (SHOWING COVER STRIPPED BACK PRE PARATORY TO USE
OF CARTRIDGE BELT.)
155



156 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
munition factory the cover strip is soft-soldered in place, with the
stripping ring at the feeding end of the box. For use the cover may
be pulled completely off, or only sufficiently so to allow the cartridge
belt to feed properly into the gun. If the box should not be emptied
it may be temporarily closed again by flattening down the cover strip
and hooking the stripping ring over a thin metal tongue riveted
for that purpose in the panel recess in the front end of the box. A
cotton web carrying strap is mounted in the panel at the rear end
of the box, held by its looped ends engaging riveted metal cleats.
In order to maintain the expendable cartridge belt in proper
alignment on the cartridges while packed in this expendable, factory-
sealed box, which must stand more transportation than the refillable
type, five guard strips of sheet metal, of box depth and proper width
and loosely strung on a connecting wire, are inserted at intervals
between the belt and the box side, between the tapered ends of the
cartridges.
WATER BOXES.
Water boxes are used for carrying the water necessary for filling
and replenishing the water jackets of water-cooled machine guns,
such as the Browning and Vickers. They are rectangular metal
boxes formed of sheet steel about one-sixteenth of an inch thick,
rustproofed by the parts of the box being zinc galvanized before
assembling, or the steel coated in the sheet with an alloy of tin and
lead. The service boxes issued, the Browning and Vickers, hold,
approximately, 2 gallons of water each, and weigh, respectively, 8
pounds and 10% pounds, when empty; 22% pounds and 26 pounds,
when full. They are filled through a hole located in an oval-
panelled recess in the side or end of box; opened by unscrewing a
quarter turn and lifting out the hinged brass carrying handle;
complete detachment of the stopper being prevented by a chain from
its base to a loose retaining ring inside the box. The boxes are
emptied by unscrewing a chained brass cap from a short valve nozzle
of small diameter on the under side or end of the box, through
which the water is poured into the machine-gun water jacket; in
the Vickers box it is also necessary to raise an interior outlet stopper,
by handle on top of box, before the water is released through nozzle.
The handle-lid has a washer-bearing, threaded flange on its base
which has the thread cut away in opposing quarter Sections of its
circumference, and the socket threading is correspondingly inter-
rupted. The lid must be placed on, therefore, by inserting its
threaded sections in the cutaway sections of the socket; then given
the quarter turn necessary to engage the threaded Sectors of flange
and socket. A semicircular cut in the lid rim aligns with an em-
bossed circle on the circle on the box to indicate the disengaged
position of the lid.
PLATE 74.
Filling cup.
WATER BOX, VICKERS, WITH MACHINE GUN WATER JACKET FILLING CUP.
PLATE 75.
BOX, BROWN ING, FRONT AND REAR VIEWS.




158 ANTIAIRCRAFT MATÉRIEL FoR MACHINE GTUNS.
For filling the machine-gun water jacket from the water box, a
leather funnel with brass nozzle (Fig. 6, plate 74) is provided.
It is carried in the machine-gun spare parts chest.
It has been found that under extreme evaporation conditions
about 4 pint of water is used up in keeping a machine gun cool
during the firing of a 250-round cartridge belt. Therefore, one
Water box of 2 gallons capacity provides enough water to cover the
firing of at least 16,000 rounds; that is, sixty-four 250-round belts,
or over fifty-three 300-round belts.
A possible development in water box application, that is con-
sidered superior to the existing method of filling the water jacket
by holding the water box over same, is the use of a force pump by
which the machine gun automatically feeds the water into its jacket
from the water box placed on the ground. This method of supply-
ing water to the gun has been tried abroad, and, as it has advantages
in easing gun operation, noninterference with fire, saving time, and
lessening exposure of gun crew, may eventually come into general
ll Se.
e THE BROWNING WATER BOX.
(Plate 75.)
This box is made of sheet steel, one-sixteenth inch thick, rust
proofed by being coated in the sheet with an alloy of tin and lead.
The parts are welded and soldered together and the outside of the
box suitably painted. The box is 12# by 7% by 4% inches in outer
dimensions. It holds nearly two gallons of water, 1.93 gallons,
United States measure, and weighs, when empty, 8 pounds; when
full, 22% pounds. The handle-lid is set in an oval recess in one end
of the box and the emptying nozzle at the other end. The filling
aperture is about 2% inches and the outlet aperture about three-
eighths inch in inner diameter. This water box is used with the
Browning machine gun.
THE VICKERS WATER BOX.
(Plate 74.)
This box is made of sheet steel, one-sixteenth inch thick. The
parts, after being formed, are rust proofed by zinc galvanizing;
then assembled by riveting and Soldering and the outside of box
painted. The box is 15 by 7% by 4% inches in outer dimensions. It
holds over two gallons of water, 2.33 gallons, United States measure.
It weighs, when empty, 10% pounds; when full, 26 pounds. The
filling aperture is approximately 2% inches and the emptying outlet
three-eighths inch in inner diameter, the same as in the Browning
PLATE 76.
CARTRIDGE BELT GUIDE.
List of parts: 1, Belt guide clips (2): 2, handle (1): 3, plate, .031 inch (1/32) thick (1);
4, rivets, .187 inch by .375 inch, countersunk (2).
152535–20–11 159

160 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
box. The handle-lid is set in an oval recess on one side of the box
and the emptying nozzle is on the opposite side. In this box, in addi-
tion to the brass cap on the nozzle, the emptying aperture is closed
interiorly by a rubber-cushioned plunger, spring pressed against the
outlet through a brass tube mounted in the box to cover Same, its
controlling rod terminating in a half-ring handle near one end of the
upper side of the box. When this valve handle is raised and turned
to one side it locks in open position; released, it shuts off the water
exit. This water box is used with the Vickers Machine Gun.
CARTRIDGE BELT GUIDE.
(Plates 76, 77, 78, 1, 31, 33, 42, 46, 48, 54.)
In using machine guns against aircraft it was found that when
firing at the high angles of elevation the cartridge belt did not feed
properly into the gun, because of its tendency to come out of the
ammunition box bodily. To insure the free feeding of the belt at all
angles of fire the cartridge belt guide was devised and is included
in the equipment of machine guns for antiaircraft work.
The Cartridge Belt Guide consists of a sheet metal cover plate for
the ammunition box which has its forward end bent upward and
side flanged so that it arches over the feeding end of the box to form
a rectangular guideway, or slot, through which the cartridge belt
feeds into the gun. The cover plate is made of thin sheet steel braced
by a narrow steel strap lengthwise of its center on the upper side,
which also forms a handle over the flat rear section of the plate.
Two steel straps, one crosswise of the cover plate at each end of the
handle brace and riveted through same to the cover, are bent over
the plate edge to form spring legs which grip the sides of the ammu-
nition box to hold the cover plate in place thereon.
In using the Cartridge Belt Guide the ammunition box cover is
opened widely and the belt guide adjusted on the box in its place,
with guide arch flush over the feeding edge of the box and the
handled section flat against the box rim and spring legs engaging
the box sides. It is used with both the Browning and Vickers
ammunition boxes.
STADIA (RANGE INDICATOR).
(Plates 25, 26, 27.)
This device is fully described and explained in Chapter W. The
type of stadia used is the Peycru, which is considered to be the best.
The Stadia (range indicator) is simply a small, oblong metal plate
with apertures of varied size in it and a bead-tipped string of about .
2 feet length attached to its center. The beaded end of the string
PLATE 77.
-
-
CARTRIDGE BELT GUIDE AS USED ON BROWN ING AM M U-
NITION BOX, SHOWING LOADING END OF BROWN ING
CARTRIDG E BELT.
161

PLATE 78.
- -
|
ſ
7-3 or *
CARTRIDGE BELT GUIDE AS USED ON VICKERS AM MUNITION BOX, SHOWING
LOAD ING END OF VICKERS CARTRIDGE BELT.
PLATE 79.
EYEGLASSES OR GOGGLES, FOR ANTIAIRCRAFT WORK WITH FLEUZAL OF
EQUIVALENT LENS (AMBER WITH A TINGE OF GREEN). ILLUSTRATING
A DES I RABLE TYPE.


162
ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS. 163
is held against the face of the user by one hand, while the stadia is
held in the other hand with its most suitably sized aperture be-
...tween the aircraft and the eye. If the approximate dimensions of
the viewed aircraft are known, its apparent size in the proper aper-
ture for its type indicates its distance, and especially whether it is
within range or not. It will be obvious that accurate knowledge of
the general dimensions of aircraft and ability to recognize types are
essential to effective use of the range indicator.
The stadia is carried in the gun-sight case.
EYEGLASSES WITH FIEUZAL LENS.
(Plate 79.)
It has been found that eyeglasses of special type are necessary to
observe aircraft to best advantage. Eyeglasses with Fieuzal lens,
such as are used by the field artillery, meet the requirements for anti-
aircraft work and have therefore been made part of the antiaircraft
machine-gun equipment. These glasses are of the usual commercial
ooggle type and there is nothing especial about them but their color,
which is amber, with a tinge of green, a tint that has proved to be
especially adapted for sky sighting.
A carrying case accompanies each pair of eyeglasses.
Half the number of pairs issued are spares, or extras, and carried in
the Spare parts chest.
40-ROUND MAGAZINE FOR BROWNING AUTOMATIC RIFLE.
(Plates 80, 81, 37.)
To obtain the best results from the Browning Automatic Rifle
when using it as an antiaircraft weapon, it was considered ad-
visable to increase its magazine capacity. The 40-round Magazine
has therefore been devised and is included with the Browning rifle as
issued for use against aircraft. By doubling the magazine capacity it
enables twice as long a burst of fire without interruption as can be
obtained with the 20-round magazine usually employed with this
rifle. As previously stated, the shortness of the time during which
an aircraft is in effective range makes it necessary to pour con-
tinuous fire into it while the opportunity lasts. The 40-round maga-
zine is of the same material and general construction as the usual
Browning 20-round magazine. It differs in having greater depth;
double capacity; a two-section elevating spring, and a curved-rec-
tangle form, curving forward from the trigger guard because of its
greater depth. It weighs, when empty, 134 ounces; when loaded with
Service ammunition, 3 pounds one-half ounce. A suitable carrying
pouch has been designed for it.
PLATE 80.
40-Round MAGAZINE FoR BROWN ING AUTOMATIC RIFLE, SHOWN IN PLACE
|N A SECTION OF THE RIFLE.
164

3.
PLATE 81
- - - --
40-ROUND MAGAZINE FOR BROWN ING AUTOMATIC RFLE, PARTS, SERVICE 20-ROUND MAGAZINE SHOWN AT LEFT SIDE FOR COMPARISON.
List of parts: 1, 40-round magazine tube (1): 2, magazine springs (2): 3, magazine follower, (1): 4, magazine spring separator (1): 5, magazine base (1).

* 2: … …ºrs:
*, * >
:: * : * ~ :- “. . . . . . . ;- , - . . . . . . . . . --> -ºº º ºsº ºr . . . .
- ," . - - - - . . . ...* *
&”
166 ANTIAIRCRAFT MATÉRIEL FOR MACHINE GUNS.
AMMUNITION.
. (Plate 5.) - .
The ammunition used in antiaircraft machine-gun work is special
and in that sense may be considered an accessory to antiaircraft
machine guns. It is described in Chapter I, paragraph 11. -
ADAPTERS.
Adapters, for adapting Service machine gun tripods and mounts
for antiaircraft use, may be considered as an antiaircraft accessory;
but have been treated as part of each tripod or mount. (See Chap-
ter VI, p. 123.) - -
- . . . . .
THE UNIVERSITY OF MICHIGAN
DATE DUE
tº AR 1 6 1994