IC-NRLF 
 
MODEL AEROPLANES 
 
 AND THEIR MOTORS 
 
Waid Carl's model in flight 
 Courtesy Edward P. Warner, Concord Model Club 
 
MODEL AEROPLANES 
 
 AND THEIR MOTORS 
 
 A Practical Book for Beginners 
 
 BY 
 
 GEORGE A. CAVANAGH 
 
 MODEL EDITOR "AERIAL AGE" 
 
 DRAWINGS BY 
 
 HARRY G. SCHULTZ 
 
 PRESIDENT THB AERO-SCIENCB CLUB OF AMERICA 
 
 WITH AN INTRODUCTION BY 
 
 HENRY WOODHOUSE 
 
 Managing Edltoi "Flying" 
 Governor of ihe Aero CluH of America 
 
 NEW YORK 
 
 MOFFAT, YARD & COMPANY 
 1916 
 
e 
 
 COPYRIGHT, 1916, Bv 
 
 MOFFATT, YARD AND COMPANY 
 
 NEW YORK 
 
 All Hfhu rturvid 
 
TO 
 M. T. H. 
 
INTRODUCTION 
 
 HISTORY tells us what some of us luckier 
 ones heard the Wright Brothers themselves 
 tell that the Wrights' active work in aero- 
 nautics was a result of the interest aroused by 
 a toy helicopter presented to them by the Rev- 
 erend Bishop Milton Wright, their father. 
 
 Tremendous developments have taken place 
 in aeronautics and aircraft are fast developing 
 in size, speed, and range of action. They 
 have revolutionized warfare, and seem to be 
 destined to become a most important factor in 
 the reconstruction that will follow the war. 
 
 The greater the development the truer the 
 fact that model aeroplanes may be instru- 
 mental in bringing to aeronautics men who 
 may make valuable contributions to aeronaut- 
 ics. As a matter of fact, there are already 
 in active life, contributing their share to the 
 development of aeronautics, young men who 
 only a few years ago competed for prizes 
 
INTRODUCTION 
 
 which the writer offered for model competi- 
 tion. 
 
 The young men who are now flying models 
 will live in the new age and they have much 
 to give and much to receive from it 
 
 Through the tremendous strides forward of 
 aeronautics there are wonderful possibilities 
 for the employment of ingenuity, genius and 
 skill, and business opportunities, as great as 
 have ever been created by progress in impor- 
 tant lines of human endeavor. Problems of 
 engineering as huge as were solved by master 
 builders; juridical and legal questions to be 
 decided as stupendously difficult as any Glad- 
 stone would wish them; possibilities for the 
 development of international relations greater 
 than were ever conceived; problems of trans- 
 portation to be solved by the application of 
 aircraft, as wonderful as any economist could 
 wish; opportunities to gain distinction splen- 
 did enough to satisfy the most ambitious 
 person. 
 
 HENRY WOODHOUSE. 
 
 New York, June 5th, 1916. 
 
LIST OF CONTENTS 
 
 PAGE 
 
 INTRODUCTION . . * ix 
 
 HISTORY OF MODEL AVIATION i 
 
 CONSTRUCTION ...... 8 
 
 Propellers Wings Frame Assembling Launching 
 Chassis Pontoons Launching an R. O. G. or Model 
 Hydroaeroplane. 
 
 WORLD RECORD MODELS 52 
 
 Lauder Distance and Duration Model Hittle Tractor 
 Hydro La Tour Flying Boat Cook No. 42 Model 
 Alson H. Wheeler Twin Pusher Biplane Rudy Funk 
 Duration Model. 
 
 COMPRESSED AIR MOTOR 83 
 
 A Simple Compressed Air Motor Wise Compressed 
 Air Motor Schober-Funk Three Cylinder Motor 
 The Schober Four Cylinder Opposed Motor, 
 
 COMPRESSED AIR DRIVEN MODELS ...... . . 92 
 
 The McMahon Compressed Air Driven Monoplane 
 The McMahon Compressed Air Driven Biplane. 
 
 GASOLINE MOTORS JOPSON MIDGET ARO GASOLINE MOTOR 112 
 
 STEAM POWER PLANTS , 114 
 
 H. H. Groves Steam Power Plants G. Harris's 
 Steam Engine Professor Langley's Steam Engine 
 French Experiments with Steam Power Plants, 
 
 WORLD'S MODEL FLYING RECORDS 119 
 
 DICTIONARY OF AERONAUTICAL TERMS . ., . . 122 
 
LIST OF ILLUSTRATIONS 
 
 PAGE 
 
 Model Aeroplane in Flight Frontispiece 
 
 First Model Aeroplane Exhibition ...... Opp. 4 
 
 Propellers (Diagram i) ,... 9 
 
 How to cut propellers (Diagram 2) u 
 
 Designs for propellers (Diagram 3) . . 14 
 
 Designs for propellers (Diagram 4) 17 
 
 Wing construction (Diagram 5) 20 
 
 Members of the Aero Science Club Opp. 22 
 
 Members of the Milwaukee," and Illinois Model Aero 
 
 Clubs Opp. 22 
 
 Frame construction (Diagram 6) . .25 
 
 Model Assembly (Diagram 7) 30 
 
 C W. Meyer and Wm. Hodgins exhibiting early type 
 
 models Opp. 32 
 
 Henry Criscouli with five foot model Opp. 32 
 
 Schultz hydroaeroplane Opp. 32 
 
 Rubber winder (Diagram 8) 35 
 
 Chassis construction (Diagram 9) ...... ... 38 
 
 Pontoon construction (Diagram 10) 43 
 
 Obst flying boat Opp. 44 
 
 McLaughlin twin tractor hydroaeroplane .... Opp. 44 
 
 Louis Bamberger hydro about to leave water . . Opp. 44 
 E. B. Hiring and Kennith Sedgwick Milwaukee Club. 
 
 How to launch R. O. G. model Opp. 48 
 
 Waid Carl, Concord Model Club. Launching R. O. G. 
 
 model Opp. 48 
 
LIST OF ILLUSTRATIONS 
 
 PAGE 
 
 Wallace A. Lauder model (Diagram n) . ...... 54 
 
 Lauder distance and duration model Opp. 56 
 
 Lauder R. 0. G. model . Opp. 56 
 
 Lindsay Hittle world record hydroaeroplane (Diagram 12) 61 
 
 La Tour Flying Boat (Diagram 13) 66 
 
 Ellis Cook R. O. G model (Diagram 14) 73 
 
 Funk duration model (Diagram 15) 78 
 
 Rudy Funk speed model Opp. 80 
 
 McMahon and Schober compressed air driven models Opp. 80 
 Alson H. Wheeler twin pusher biplane .... Opp. 82 
 
 C. V. Obst tractor . , Opp. 82 
 
 Simple compressed air motor (Diagram 16) 85 
 
 Schober compressed air driven monoplane . . . Opp. 88 
 Schober compressed air driven biplane .... Opp. 88 
 John McMahon and compressed air driven mono- 
 plane Opp. 94 
 
 Frank Schober preparing model for flight . . . Opp. 94 
 John McMahon pusher biplane (Diagram 17) ... . 98 
 
 Wise compressed air motor Opp. 100 
 
 Schober-Funk five-cylinder rotary motor .... Opp. 100 
 
 Schober four cylinder engine (Diagram 18) 103 
 
 Jopson gasoline motor . Opp. 104 
 
 Sectional view of Jopson motor (Diagram 19) ... 108 
 Power curve of Jopson motor (Diagram 20) . . . .in 
 
 Midget gasoline motor Opp. 112 
 
 English steam power plant , . Opp. 116 
 
 V. E. Johnson steam driven hydroaeroplane . . . Opp. 116 
 
 English compressed air driven biplane Opp. 118 
 
 Tractor hydroaeroplane fitted with steam power plant . . 
 
 .... Opp. 118 
 
 English compressed air motor fitted with simple speed- 
 ometer ; ........ Opp. 118 
 
MODEL AEROPLANES 
 
 HISTORY OF MODEL AVIATION 
 
 MODEL aeroplaning, as a sport, was first in- 
 troduced in America during the. year of 1907. 
 It was then that the first model aeroplane club 
 in America was formed by Miss E. L. Todd, 
 with the assistance of Mr. Edward Durant, 
 now Director of the Aero Science Club of 
 America. Prior to this the model aeroplane 
 was considered an instrument of experimenta- 
 tion or, when built to resemble a full sized 
 machine, was used for exhibition purposes. 
 Noted scientists, men such as Maxim, Langley, 
 Eiffel and others, depended largely on models 
 to bring about the desired results during their 
 experiments. Before the Wright Brothers 
 brought forth and launched the first heavier 
 than air machine their experiments, to a great 
 
2 MODEL AEROPLANES 
 
 extent, were confined to model aeroplanes. 
 There is little doubt but that a large majority 
 of aviators engaged in flying machines in dif- 
 ferent parts of the world were at one time in 
 their career interested in the construction and 
 flying of model aircraft, and from which no 
 doubt they obtained their initial knowledge of 
 the aeroplane, in so far as the same principles 
 and laws apply to any aeroplane, regardless of 
 its size. 
 
 The first model aeroplane club went under 
 the name of the New York Model Aero Club 
 and during its existence a great many of its 
 contests were carried on in armories. The 
 reason for this was because of the fact that the 
 greater number of the models prevalent at that 
 time were built along the lines of full sized 
 machines, and their manner of construction 
 was such as to interfere with the flying ef- 
 ficiency of the model. Streamline construction 
 was something unknown to model constructors 
 in those days and, in consequence, crudely con- 
 structed and heavy models were very often evi- 
 
HISTORY 3 
 
 denced, and, as a result, flights of over one 
 hundred feet were very seldom made. At about 
 the same time model enthusiasts in both Eng- 
 land and France were actively engaged in con- 
 structing and flying models, but the type of 
 model used was of a different design from those 
 flown by the American modelists and as a re- 
 sult of this innovation many of the early rec- 
 ords were held abroad. The type of model 
 flown by the English modelists resembled in ap- 
 pearance the letter "A," hence the term "A" 
 type. 
 
 It was not long after the introduction of this 
 type of model in America that model aero- 
 planing as a sport began to assume an aspect of 
 great interest. Models were constructed along 
 simpler lines and with a greater tendency 
 toward doing away with all unnecessary parts, 
 thus increasing the flying qualities of the 
 models. Flights of greater distance and dura- 
 tion were the objects sought and, in their efforts 
 to achieve them new records were made at most 
 every contest, until flights of from 500 to 1000 
 
4 MODEL AEROPLANES 
 
 feet were common occurrences. By the use of 
 the A type model and the single stick model 
 which made its appearance shortly after the A 
 type model, American modelists succeeded in 
 breaking most of the world records for this 
 type of model which is now termed by English 
 modelists "flying sticks." 
 
 One by one model aeroplane clubs were 
 formed in different parts of the country until 
 to-day there are in existence about twenty-five 
 clubs and all with memberships of from two to 
 eight times that ojf the first model aero club. 
 The work which was started by the New York 
 Model Aero Club is now being carried on by the 
 Aero Science Club of America and its affiliated 
 clubs. The interest in model flying grew to 
 such an extent that during the year of 1915 the 
 Aero Club of America decided to hold the First 
 National Model Aeroplane Competition for the 
 purpose of offering to the young men of Amer- 
 ica an opportunity of becoming acquainted 
 with this new sport and its advantages. The 
 results of this competition were beyond expec- 
 
HISTORY 5 
 
 tation. Models were made capable of flying 
 distances and with durations that, to the 
 early flyers, seemed impossible. In the hand 
 launched contests models were flown for dis- 
 tances ranging from 2000 to 2500 feet, the win- 
 ning flight being 3537 feet, and it might also 
 be said that the contestant who flew this model, 
 with a model of the same design established a 
 duration record of 195 seconds. As this goes 
 to press, information is received that the 
 World's Record for distance for hand launched 
 models has been broken by Thomas Hall, of 
 Chicago, 111., an Illinois Model Aero Club mem- 
 ber, with a flight of 5337 feet. Another in- 
 teresting result of the competition was the es- 
 tablishing of a world hydroaeroplane record by 
 a member of the Illinois Model Aero Club with 
 a model of the tractor type, a f our-bladed pro- 
 peller being used in connection with the model. 
 The flying boat which is a late advent to the 
 field of model flying also proved a record 
 breaker in this competition, having remained in 
 the air after rising from the surface of the 
 
6 MODEL AEROPLANES 
 
 water, for a duration of 43 seconds. This 
 model was flown by a member of the Pacific 
 Northwest Model Aero Club of Seattle, Wash- 
 ington. The establishing of these records 
 clearly indicates the advantage of scientific de- 
 signing and construction and careful handling. 
 So satisfactory have been the results of the 
 First National Model Aeroplane Competition 
 that the Aero Club of America has made ar- 
 rangements for holding the Second National 
 Model Aeroplane Competition during the 
 year 1916. But in the announcement of the 
 Second National Competition the Aero Club of 
 America has made provision for the holding of 
 contests for mechanically driven models, in 
 view of the interest which is being shown by 
 model flyers in the construction of models 
 more closely resembling large machines to be 
 driven by compressed air, steam and gasoline 
 power plants. This is the outcome of a desire 
 on the part of model constructors to substitute 
 for what is now commonly known as the "flying 
 stick," models more closely resembling large 
 
HISTORY 7 
 
 machines, which models can be more satisfac- 
 torily flown by the use of compressed air, steam 
 or gasoline power plants. As in the early days, 
 the best flights made by models using com- 
 pressed air and steam have been made by Eng- 
 lish flyers, the duration of the flights ranging 
 anywhere from 25 to 50 seconds. 
 
 Whether or not the American flyers will re- 
 peat history and achieve greater results with 
 this type of model motive power is something 
 that can only be determined in the future. But 
 in any event the scientific mechanically driven 
 model will, without doubt, assume an important 
 position in the field of model aviation. 
 
CONSTRUCTION 
 
 PROPELLERS 
 
 PROPELLERS may be cut from various kinds 
 of wood, but the most suitable, from every 
 standpoint, is white pine. The advantage of 
 using this wood lies in the fact that the propel- 
 lers may be cut more rapidly and when cut are 
 lighter than those made from most other kinds 
 of wood. When coated with the proper kind 
 of varnish they are sufficiently strong for or- 
 dinary flying. Wood selected for propellers 
 should be free from knots, holes and other im- 
 perfections and it is very desirable that it 
 should be of perfectly straight grain. 
 
 A piece of such clear white pine 8" long, i" 
 wide and 4" thick should be selected and on 
 one side marked TOP. A tracing of the pro- 
 peller similar in design to Figure I, should be 
 laid on this piece of wood and an imprint of the 
 
 propeller design drawn on the TOP side. To 
 
 8 
 
CONSTRUCTION 
 
 Diagram I 
 
10 MODEL AEROPLANES 
 
 find the center of the block two lines should be 
 drawn from the opposite corners, their point of 
 meeting being approximately in the center 
 near enough for all practical purposes to insure 
 greater accuracy. Similar lines should be 
 drawn from the corners on the BOTTOM side of 
 the block of wood. A hole 3-32 of an inch in 
 diameter should be bored through the center 
 thus obtained, through which the propeller 
 shaft will be inserted when the propeller is 
 finished. The two sections of the propeller 
 blades drawn in diagrammatical form on the 
 TOP of the block, should be marked respec- 
 tively BLADE i and BLADE 2, as shown in 
 diagram I. The block is then ready for the 
 commencement of the actual cutting. In cut- 
 ting out the propeller, BLADE i should be held in 
 the left hand and the knife in the other, with 
 the blade of the knife on the straight edge of 
 BLADE i. The cutting should be carried out 
 very carefully with attention constantly paid to 
 Fig. 2-, and should be stopped when the line 
 shown in Fig. 2 has been reached. The semi- 
 
 
CONSTRUCTION 
 
 II 
 
 Diagram 2 
 
12 MODEL AEROPLANES 
 
 blade should then be sandpapered until a small 
 curve is obtained by which the propeller will be 
 enabled to grip the air. 
 
 To cut BLADE 2, BLADE I should be held in 
 the left hand and BLADE 2 cut until the line 
 shown in Fig. 3 is reached, after which the 
 sandpapering process is carried out in the same 
 manner as in the case of BLADE i. During all 
 of the foregoing operations it must be clearly 
 borne in mind that the TOP of the blank pro- 
 peller must always face upward, and the cutting 
 should always be done on the STRAIGHT lines. 
 Should the straight edge be cut on one edge of 
 the blank propeller and the curved edge on the 
 other, it would result in the blades of the 
 finished propeller having a tendency to push in 
 opposite directions and in consequence no pro- 
 pulsion of the model would be possible. 
 
 Attention should next be turned to the back 
 of the propeller blank on which the manner of 
 cutting is exactly like that suggested for the top 
 side, with the exception that instead of cutting 
 along the STRAIGHT lines, the cutting is done 
 
CONSTRUCTION > 13 
 
 along the CURVED lines. In this part of the 
 work great care is to be exercised for by the 
 time the necessary cutting has been done on the 
 back of the propeller the entire structure is very 
 fragile and one excessive stroke of the knife 
 may result in destroying the entire propeller 
 blade. By constantly holding the wood to the 
 light it is possible to determine with a reason- 
 able degree of accuracy the evenness of thick- 
 ness. To complete the BOTTOM side of the pro- 
 peller the blade should be sandpapered as was 
 the top. 
 
 The method of cutting the second propeller 
 is exactly that used in cutting the first propeller, 
 only that the diagram shown in Fig. 4 should be 
 used. This will result in two propellers being 
 made that will revolve in opposite directions in 
 order to produce even and balanced propulsion. 
 If both propellers revolved in the same direc- 
 tion the effect would be to overturn the model. 
 
 In diagram I the propellers are shown with 
 the straight edge as the entering or cutting 
 edge of the blade. Some of the model builders 
 
MODEL AEROPLANES 
 
 Diagram 3 
 
CONSTRUCTION 15 
 
 prefer the curved edge as the cutting edge 
 (diagram 2). It is significant that Mr. Frank 
 Schober, a well known model constructor, 
 tested both designs on his compressed air 
 driven model, and while both propellers were 
 the same in weight, diameter and pitch, the 
 one having the straight edge as the cutting 
 edge was found one-third more efficient. 
 
 When the propellers have been given a light 
 coat of shellac they should be laid aside until 
 the assembling of the complete model. 
 
 By following the foregoing instructions a 
 simple and effective set of propellers will be 
 produced. But in order to vary the experi- 
 mental practice of the constructor various other 
 diagrams, Nos. 3 and 4, illustrating suitable 
 designs, are provided and can be made by ap- 
 plying the above general theory and using the 
 diagrams herewith. 
 
 WINGS 
 
 One of the most important considerations in 
 the construction of a model is the making of the 
 
16 MODEL AEROPLANES 
 
 wings. To obtain the greatest efficiency the 
 wings must be carefully designed, with due at- 
 tention to whether the model is being con- 
 structed for speed, duration or climbing ability. 
 Attention should be given to streamline con- 
 struction ; that is, the parts of the wing should 
 be so assembled that the completed wing would 
 offer the least possible resistance to the air, if 
 the best results are to be obtained. 
 
 For the main wing three strips of spruce, 
 each 30" in length, two of them being 3-16" x 
 J4" and the third 3-16" x 1-16" are required. 
 To make them thoroughly streamline all edges 
 should be carefully rounded off and all surfaces 
 should be smooth. A strip of bamboo at least 
 20" long, y 2 " wide, J^" thick, should be cut 
 into pieces, each piece to be 5 in. long. To 
 secure the necessary curve, %" depth, the 
 pieces of bamboo should be held in steam and 
 slowly bent in a manner closely resembling the 
 skids of an ordinary bob-sled. When the 
 curvature has been obtained, care should be 
 exercised in cutting each piece into four longi- 
 
CONSTRUCTION 
 
 Diagram 4 
 
18 MODEL AEROPLANES 
 
 tudinal strips, from which twelve should be 
 selected to be used as ribs, each to be J^j" 
 wide. The bending of the bamboo preliminary 
 to making the ribs is done in order to secure uni- 
 formity of curvature. 
 
 When this has been done the ribs are ready 
 for fastening to the sticks entering and trail- 
 ing edges and each must be attached an equal 
 distance apart. In order that the ribs may be 
 evenly spaced it is necessary to put a mark 
 every 3" on the larger stick or entering edge 
 of the wing, and also on the flat stick or trailing 
 edge. The main beam which is of the same 
 dimensions as the entering edge is afterwards 
 fastened across the center of the wing, and does 
 not necessarily need to be thus marked, as it is 
 fastened to the ribs after the ribs have been 
 attached to the entering and trailing edges of 
 the wing frame. By holding the ribs one at a 
 time so that the curved edge rests upon the en- 
 tering edge where the mark indicates, as shown 
 in diagram 5, they should be fastened thereon 
 by means of thread and glue. The rear end of 
 
CONSTRUCTION 19 
 
 the rib must be fastened to the trailing edge 
 where the mark indicates, also by thread and 
 glue. 
 
 After all ribs have been thus securely fast- 
 ened to both edges of the frame the third stick, 
 or main beam, should be attached to the frame 
 on the underside, the fastening being made at 
 the highest point of the curve of each rib. This 
 main beam prevents the wing covering from 
 drawing in the end ribs and adds very materi- 
 ally to the strength of the entire wing struc- 
 ture. To cover the wings fiber paper may be 
 used and is a suitable material, but the best re- 
 sults, from a standpoint of flying efficiency and 
 long service, are obtained by the use of China 
 silk. 
 
 The frame of the forward wing or elevator 
 is made in the same manner as is the main wing, 
 but it is only 12" in span by 4" in chord, and 
 is constructed without the use of a main 
 beam. This wing has only five ribs which are 
 made in the same manner as those for the rear 
 wing, and each is placed a distance of 3" apart. 
 
20 
 
 MODEL AEROPLANES 
 
 
 I 
 
 Diagram 5 
 
CONSTRUCTION 21 
 
 A piece of silk measuring 2" longer and 2" 
 wider than each of the wing frames should 
 be used in covering the wings, and this can be 
 held in position by the use of pins prior to the 
 actual sewing. The extra inch of silk on all 
 sides of the frame is placed around the under 
 side of the frame in order that it can be made 
 thoroughly taut when the silk has been sewn 
 close to the edges of the frame. After the silk 
 has been sewn close to the edges the pins may be 
 removed and the surplus silk that hangs from 
 the under side of the frame may be cut off. To 
 make this silk airproof it should be coated with 
 a thin coat of shellac or varnish and the wings 
 should be thoroughly dry before being used. 
 This coating, in addition to airproofing, will as- 
 sist in making the covering perfectly taut, and 
 also in making the wing ready for service when 
 the entire model is ready to be assembled. 
 
 FRAME 
 
 As all other parts of the model are attached 
 to the frame in addition to its having to stand 
 
22 MODEL AEROPLANES 
 
 the strain of the tightly wound rubber strands 
 which serve as the motive power for the model, 
 it must be made strong. It is therefore neces- 
 sary to exercise care and judgment in making 
 certain that the different units that make up the 
 frame are rightly proportioned and are of the 
 proper material. Just as in the large sized 
 aeroplanes there are many types of bodies, so 
 there are many different types of frames in use 
 in model construction, but the standard, and 
 for all practical purposes the best frame, re- 
 sembles the letter A in shape, hence the name 
 A type. The lightness of the frame depends 
 entirely on the materials used and the manner 
 in which it is constructed. 
 
 Some model flyers use but a single stick for 
 the frame, but generally the A type frame is 
 preferred for the reason that it is more durable, 
 the wings can be more securely attached to it, 
 and that it is possible of developing very much 
 better results. 
 
 To construct such an A type frame 2 main 
 sticks to serve as frame side members are neces- 
 
Members of the Aero Science Club 
 
 Members of the Milwaukee and Illinois Model Aero Clubs 
 
CONSTRUCTION 23 
 
 sary and are made from spruce. Each member 
 should be 36" in length, y%" in depth by J4" in 
 width. By rounding the edges and smoothing 
 the various surfaces with sandpaper streamline 
 effect will be secured and will add to the ef- 
 ficiency of the machine as well as to its appear- 
 ance. When the side members are placed in A 
 formation the extremity of the sticks at which 
 they meet should be so tapered in the inner 
 sides that when they meet and are permanently 
 fastened the result will be a continuance of the 
 general streamline effect. The permanent 
 fastening of the frame side members at the 
 point of the A may be accomplished by using 
 either strong fish glue or better, a good water- 
 proof glue and then have the jointure rein- 
 forced by securing a piece of 3-32" steel wire 3" 
 in length and placing the center of it at the 
 point of the A, afterwards bending the wire 
 along either outer edge of the frame side mem- 
 bers, putting as much pressure on the wire as 
 the strength of the structure will permit; after 
 this the reinforced jointure should have thread 
 
24 MODEL AEROPLANES 
 
 wound around it to insure even greater 
 strength. About y*" of the wire on each side 
 of the point should be left clear and afterwards 
 turned into a loop as shown in diagram 6, for 
 the purpose of attaching the hooks that hold 
 the rubber strands. To hold the side members 
 apart at the rear end and for a propeller brace, 
 a piece of bamboo 10" long, J^" thick by J^" 
 in width is required and this should be fastened 
 to the extreme rear ends of the frame side mem- 
 bers, allowing the propeller brace to protrude 
 on either side ij4" as illustrated. To put the 
 propeller brace in position a slot *^" deep by 
 Y&" wide should be cut into the rear ends of the 
 frame side members for the reception of the 
 propeller brace. After the brace has been 
 placed in position the outer edge should come 
 flush with the rear ends of the side members. 
 To hold the brace in place thread and glue 
 should be used in the same manner as described 
 for the point of the frame side members. Be- 
 tween the point of the frame and the propeller 
 brace two bamboo pieces, one 9" long and an- 
 
CONSTRUCTION 
 
 Diagram 6 
 
26 MODEL AEROPLANES 
 
 other 2 1-3" long, should be used as braces for 
 the general strengthening of the structure. 
 The longest piece should be secured across the 
 top of the frame about 9" from the rear and 
 the shorter piece about 9" from the point. 
 
 When these two braces are in position the 
 next matter that calls for the attention of the 
 constructor is the matter of getting into posi- 
 tion at the two outer extremities of the pro- 
 peller brace bearings for the propellers. For 
 this purpose two pieces of 3~32nd inch brass 
 tubing, each y^th of an inch long, should 
 be used, and should be fastened to the under- 
 side of the propeller brace, at each extremity of 
 that brace, by the use of thread and glue. 
 Sometimes greater efficiency is secured by put- 
 ting these pieces of bronze tubing about y^" 
 from the end. Some model constructors make 
 a very neat jointure here by soldering the piece 
 of tubing to a strip of thin brass, which is bent 
 over the end of the propeller brace and bound 
 and glued thereon. In fastening the bronze 
 tubing to the propeller brace it should be so 
 
CONSTRUCTION 27 
 
 adjusted that it will run parallel to the side 
 members of the frame and will therefore offer 
 the least possible resistance to the shaft of the 
 propeller when the rubber strands have been 
 attached. 
 
 When the frame has been completed a coat 
 of shellac should be applied to the entire struc- 
 ture to render it damp-proof. 
 
 ASSEMBLING 
 
 The proper assembling of the parts of the 
 model is as essential to good results as is the 
 designing and making. Parts, although prop- 
 erly made, if improperly placed in relation to 
 each other will very often lead to trouble. 
 Therefore very great care must be exercised in 
 the assembling process. 
 
 When all the parts have been prepared and 
 are ready to be assembled the first thing that 
 should be done is to mount the propellers in 
 position. This must be done very carefully on 
 account of the fact that the propeller shafts 
 are easily bent and if bent the result is consider- 
 
28 MODEL AEROPLANES 
 
 able trouble, for such a bend in the propeller 
 shaft will cause the propeller to revolve irregu- 
 larly with a consequent loss of thrust. Before 
 inserting the propeller shafts in the tubing 4 
 washers each y$" in diameter should be cut 
 from hard metal, and a hole large enough for 
 the propeller shaft to pass through should be 
 bored in the center of each washer. The metal 
 washers should be passed over the straight ends 
 of the shafts which extend from the rear of 
 the tubing, after they have been inserted in the 
 tubing, and in this manner the cutting into the 
 hubs of the propellers which would follow is 
 avoided. The propellers are now to be 
 mounted and this is accomplished by allowing 
 the ends of the shafts, which extend out from 
 the rear of the tubing, to pass through the hole 
 in the hub of each propeller. In mounting the 
 propellers it is absolutely necessary to have the 
 straight edge of the propellers to face the point 
 or front end of the model. The propeller 
 shown in Fig. 4 of diagram i, should be 
 mounted on the left side of the frame to revolve 
 
CONSTRUCTION 29 
 
 to the left, while the propeller shown in Fig. i 
 should be mounted on the right side of the 
 frame to revolve to the right. When the pro- 
 pellers have thus been mounted the one-half 
 inch of shafting which extends out from the 
 hubs of the propellers should be bent over to 
 grip the propeller hub and thereby prevent the 
 shaft from slipping during the unwinding of 
 the rubber strands. For the reception of the 
 rubber strands to provide motive power a hook 
 must be formed in each shaft and this can be 
 done by holding securely that portion of the 
 shaft which extends toward the point of the 
 model, while the end is being formed into a 
 hook as illustrated in diagram 7. 
 
 Eighty- four feet of J^th" flat rubber is 
 necessary to propel the model. This should be 
 strung on each side from the hooks (see dia- 
 gram) at the front part of the model to the pro- 
 peller shafts at the rear of the model. In this 
 way 14 strands of rubber will be evenly strung 
 on each side of the frame. To facilitate the 
 winding of the rubbers two double hooks made 
 
MODEL AEROPLANES 
 
 Diagram 7 
 
CONSTRUCTION 31 
 
 of 3~3 2 " steel wire to resemble the letter S, 
 as shown in diagram 7, should be made. One 
 end of this S hook should be caught on the 
 frame hook, while the other end is attached to 
 the strands of rubber, and to prevent the pos- 
 sible cutting of the strands a piece of rubber 
 tubing is used to cover over all wire hooks that 
 come in contact with the rubber strands pro- 
 viding propelling power. 
 
 The wings are mounted on the top side of the 
 frame members by means of rubber bands and 
 in placing them upon the frame it should be 
 noted that the entering edge of each wing must 
 face the point or front of the model. The 
 wings must be so adjusted on the frame that 
 they result in perfect side balance which means 
 that there is an even amount of surface on 
 either side of the model. To secure a longi- 
 tudinal balance it will be found that the enter- 
 ing edge of the main wing should be placed 
 approximately 8" from the propeller brace or 
 rear of the model, and the entering edge of the 
 small wing or elevator approximately 6" from 
 
32 MODEL AEROPLANES 
 
 the point. But it is only by test flying that a 
 true balance of the entire model can be obtained. 
 To give the necessary power of elevation 
 (or lifting ability) to make the model rise, a 
 small block of wood about i" long by %" 
 square must be placed between the entering 
 edge of the small wing and the frame of the 
 model. 
 
 After the wings have been thus adjusted and 
 a short test flight made to perfect the flying and 
 elevating ability of the model, and this test 
 flight has been satisfactory, the model is ready 
 for launching under its full motive power. 
 
 LAUNCHING 
 
 In the preliminary trials of a model close at- 
 tention must be paid to the few structural ad- 
 justments that will be found to be necessary 
 and which if not properly and quickly remedied 
 will result in the prevention of good flights or 
 even in possible wrecking of the model. Care- 
 ful designing and construction are necessary 
 but it is equally as important that the model 
 
Charles W. Meyers and Henry Criscouli and his five 
 William Hodgins exhibit- foot model. This model 
 
 may be disassembled and 
 packed conveniently in 
 small package 
 
 ing models of early de- 
 sign. 
 
 Harry G. Schultz hydroaeroplane 
 
CONSTRUCTION 33 
 
 should be properly handled when it is complete 
 and ready for flying. 
 
 The approximate idea of the balance of a 
 model can be secured by launching it gently into 
 the air. If the model dives down point first it 
 indicates that the main wing should be moved 
 a little toward the front. If it rises abruptly 
 the main wing should be moved slightly toward 
 the rear. In this way by moving the wing for- 
 ward or rearward until the model glides away 
 gracefully and lands flat upon the ground, 
 proper adjustment of the balance can be ef- 
 fected. If when launching from the hand the 
 model should curve to the left the main wing 
 should be moved slightly to the left of the frame 
 members. And if the curve is to the right the 
 main wing should be moved in that direction. 
 This process can be continued until the model 
 flies in the course desired. 
 
 The winding of the rubber strands to get the 
 necessary propelling power is an important de- 
 tail. The model should be firmly held by some 
 one at the rear with the thumb on either side 
 
34 MODEL AEROPLANES 
 
 member, pressing down on the jointure and 
 with the four fingers of each hand gripping the 
 under side of the frame members, and in this 
 way holding the model steady and until the 
 rubber strands have been sufficiently wound. 
 With the hands in this position the propellers, 
 of course, cannot and should not revolve. The 
 hooks attached to the rubber strands at the 
 point or front of the model should be detached 
 from the side members and affixed to the hooks 
 of the winder. A winder may be made from 
 an ordinary egg beater as is shown in diagram 
 8. When the hooks attached to the rubber 
 strands at the point of the model have been 
 affixed to the winder the rubbers should be 
 stretched four times their ordinary length 
 (good rubber being capable of being stretched 
 seven times its length) and the winding com- 
 menced, the person winding slowly moving in 
 towards the model as the strands are wound. 
 If the ratio of the winder is 5 to I, that is if the 
 rubber is twisted five times to every revolution 
 of the main wheel of the winder, 100 turns of 
 
CONSTRUCTION 
 
 35 
 
 Diagram 8 
 
36 MODEL AEROPLANES 
 
 the winder will be sufficient for the first trial. 
 This propelling power can be increased as the 
 trials proceed. When the winding has been 
 accomplished the rubber hooks should be de- 
 tached from the winder hooks and attached to 
 the hooks at the front of the side members as 
 shown in the diagram. 
 
 In preparation for launching, the model 
 should be held above the head, one hand holding 
 it at the center of the frame, the other in the 
 center of the propeller brace in such a way as 
 to prevent the propellers from revolving. 
 When the model is cast into the air if it is prop- 
 erly adjusted it will fly straight ahead. 
 
 A precaution which is sometimes worthy of 
 attention before the launching of the model 
 under its full power is to test out the propellers 
 to find out whether or not they are properly 
 mounted and whether they revolve evenly and 
 easily. To do this the rubber strands may be 
 given a few turns, enough to revolve the pro- 
 pellers for a brief period, while the machine is 
 held stationary. If the shafts have been prop- 
 
CONSTRUCTION 37 
 
 erly inserted in the hubs of the propellers and 
 have not been bent during the winding of the 
 rubbers, the propellers will revolve evenly and 
 readily. If the propellers revolve unsteadily it 
 indicates that there is a bend in the propeller 
 shafts or the propellers have not been properly 
 balanced. If the trouble is a bend in the shaft, 
 it must be removed before the model is 
 launched on actual flight. If the propeller 
 does not revolve freely the application of some 
 lubrication (such as vaseline) to the shaft 
 will eliminate this trouble. With these adjust- 
 ments made satisfactorily, the model can be 
 launched with the anticipation of good flying. 
 
 CHASSIS 
 
 The preceding instructions and discussions 
 have dealt with different parts of a simple 
 model to be used as a hand-launched type of 
 model. The experience which will come as the 
 result of flying this type of model for a period 
 will undoubtedly tend toward a desire on the 
 part of the constructor to make his model more 
 
MODEL AEROPLANES 
 
 Diagram 9 
 
CONSTRUCTION 39 
 
 nearly represent a large sized aeroplane and 
 will make him want to have his model rise from 
 the ground under its own power. Such a 
 model is known as an R. O. G. type, that is, 
 rises off the ground. To meet this desire all 
 that it is necessary to do is to make a chassis, 
 or carriage, which can be secured to the frame 
 of the model, and with extra power added, will 
 result in a practical R. O. G. model. In con- 
 structing such a chassis or carriage it is neces- 
 sary to bear in mind that it must be made suffi- 
 ciently strong to withstand the shock and stress 
 which it will be called upon to stand when the 
 model descends to the ground. 
 
 For the main struts of the chassis two pieces 
 of bamboo each 9" in length are needed and 
 these should be bent over i" on one end as 
 shown in the diagram, that they may be fast- 
 ened to the under side of the frame members, 
 one on either side, at a point on that member 
 12" from the front. Two similar pieces of 
 bamboo, each piece about 7" in length, are re- 
 quired to act as braces between the frame mem- 
 
40 MODEL AEROPLANES 
 
 bers and the main chassis struts. Each end of 
 each of the braces should be bent over in the 
 same direction and in the same manner as that 
 described for the main strut so that the fasten- 
 ing to the main frame member and the main 
 chassis strut may be accomplished. Steam 
 may be used in bending the ends of the pieces 
 of bamboo. To make the landing chassis suffi- 
 ciently stable to withstand landing shocks a 
 piece of bamboo 9" should be fastened from 
 either side of the main chassis struts at the 
 point where the chassis brace on either side 
 meets with main strut. The ends of this cross 
 brace should be bent in similar fashion to the 
 other braces to enable its being fastened easily 
 and securely. 
 
 Two small wheels constitute the running gear 
 for the front part of the chassis, for which two 
 pieces of 1-16" steel wire each 2 l /" long 
 are required. These small wires are fastened 
 to the bottom ends of the main struts, and to 
 accomplish this the wire should be bent in the 
 center at right angles ; one leg of the angle is 
 
CONSTRUCTION 41 
 
 attached to the bottom end of the main strut as 
 shown in the diagram. Disks for wheels may 
 be cut from a bottle cork which should be ^4" 
 in diameter by approximately y\" in thickness. 
 The edges should be rounded off to prevent 
 chipping. Before mounting the wheels on the 
 axles which have been provided by the wires at- 
 tached to the bottom of the main struts, a piece 
 of bronze tubing 3-32" inside diameter and 
 3-16" long should be inserted in the center of 
 each disk. To secure the least possible resist- 
 ance on the revolutions of the wheels, there 
 should be placed on the wire axles pieces of 
 bronze tubing similar in diameter and y%" in 
 length on either side of the wheel (see illustra- 
 tion). When the wheel is thus placed in posi- 
 tion with the pieces of bronze tubing on either 
 side about %" of the axle wire will extend from 
 the outward end of the outside piece of tubing. 
 This should be bent over the tubing to prevent 
 its falling off and at the same time hold the 
 wheel securely in position. 
 
 For the rear skid a piece of bamboo 6" long 
 
42 MODEL AEROPLANES 
 
 is used, one end of which is curved as in a 
 hockey stick so that it will glide smoothly over 
 the ground. The other end of the rear skid 
 should be bent over about y*" so that it can be 
 securely fastened to the propeller braces, as il- 
 lustrated in the diagram. Two 7" pieces of 
 bamboo are required to act as braces for the 
 rear skid. Both ends of each brace strut are 
 bent over J4" in the same direction, one end of 
 each strut is securely fastened to a side mem- 
 ber 3" from the rear and the other end of each 
 strut is fastened to the rear skid, at their point 
 of meeting as shown in diagram 9, the method 
 of attaching being the same as in the case 
 of the forward portion of the chassis. All 
 joining should be accomplished by first gluing 
 the braces and then binding with thread. 
 When completed, the rear skid should glide 
 along the ground in bobsled fashion, thus pre- 
 venting the propellers from hitting the ground. 
 In making such a chassis or carriage the en- 
 deavor should be made to use, as near as pos- 
 sible, the same weight of material on either side 
 
CONSTRUCTION 
 
 43 
 
 Diagram 10 
 
44 MODEL AEROPLANES 
 
 of the model so as little interference as possible 
 will be made with the general balance of the 
 model in flight. 
 
 PONTOONS 
 
 Having satisfactorily developed the hand 
 launched model and the model rising off the 
 ground under its own propulsion the construc- 
 tor will next turn his mind to the question of 
 having his model rise under its own power from 
 the surface of the water in the fashion of pas- 
 senger-carrying hydros and flying boats. This 
 will be accomplished by the use of pontoons at- 
 tached to a specially designed chassis. 
 
 Three pontoons are necessary and these 
 should be made as light as possible. Each pon- 
 toon should be made 6" long, i" deep toward 
 the forward part, by 4" at the rear and 2" 
 wide. The side members of each pontoon are 
 made from pieces of thin white pine wood 
 i-32nd of an inch thick, slightly curved up at 
 the front and sloped down toward the rear. 
 Small niches should be made on the top and bot- 
 tom sides of the pontoons into which the cross 
 
C. V. Obst World record 
 flying boat 
 
 Twin tractor Hydroaeroplane 
 designed and constructed 
 by George F. McLaughlin 
 
 Louis Bamberger's hydro about to 
 leave surface of water 
 
CONSTRUCTION 45 
 
 braces are inserted and glued. Further refer- 
 ence to diagram 10 will show that at the ex- 
 treme forward end of the sides a cut is made 
 large enough to receive a flat piece of spruce 
 1-16" wide. Another cut of the same dimen- 
 sions is made at the extreme rear end. Still 
 further cuts are made on the top and bottom 
 sides of the pontoons, the forward cuts meas- 
 uring \y 2 " from the front and the rear cuts 
 i J4" from the rear, to join the sides of the pon- 
 toons as illustrated in diagram 10. Six pieces 
 of i -i 6" flat spruce are required for the rear 
 pontoon, the ends of which are held in posi- 
 tion by glue. For the forward pontoon only 4 
 braces are required in so far as the ends of the 
 two main brace spars of the forward part of 
 chassis are inserted in the cuts on the top sides 
 of the pontoon. These brace spars measure 10 
 inches in length and are made from bamboo 
 2/8 th inch in diameter, which necessitates en- 
 largement of the cuts on the top sides of the 
 forward pontoons so that the extreme ends of 
 the spars can be inserted in the cuts in the place 
 
46 MODEL AEROPLANES 
 
 of the braces. To complete the rear pontoon 
 and prepare it for covering, three strips of 
 y%" bamboo are required for struts. Two of 
 these strips should measure 9" in length and 
 should be attached to the front of the pon- 
 toon on the inner side as shown in diagram 10. 
 Thread and glue should be used in attaching 
 the ends of the strips to the pontoon. To en- 
 able fastening to the frame the upper ends of 
 the bamboo strips should be bent over about 
 y 2 ". The third strip should measure 8" in 
 length and is attached to the upper and lower 
 braces toward the front of the pontoon as 
 shown in the diagram. It is necessary that 
 this strip be secured in the approximate center 
 of the pontoon to insure a good balance. For 
 the purpose of securing the upper end of the 
 third strut to the center of the propeller brace 
 a piece of wire ij^" long should be secured to 
 the upper end of the strut and looped as shown 
 in diagram 10. The three pontoons should 
 now be covered with fiber paper and it is neces- 
 sary to exercise care to avoid punctures. For 
 
CONSTRUCTION 47 
 
 the purpose of coating the fiber paper to render 
 it waterproof, a satisfactory solution can be 
 made by mixing banana oil with celluloid until 
 it has attained the desired thickness, after 
 which it should be applied to the covering of 
 the pontoons with a soft brush. 
 
 For the main strut of the forward portion of 
 the chassis two pieces of Y" bamboo, each 
 11" in length, are required and these should 
 be bent over i" on one end as shown in the 
 diagram, that they may be fastened to the un- 
 der side of the frame members, one on either 
 side at a point on that member n" from the 
 front. Two similar pieces of bamboo, each 
 piece 8" in length, are required to act as braces 
 between the frame members and the main 
 chassis struts. Each end of tfye braces should 
 be bent over in the same direction and in the 
 same manner as that described for the main 
 struts so that the fastening to the main frame 
 member and the main chassis struts may be 
 accomplished. Steam or an alcohol lamp may 
 be used in bending the ends of the pieces of 
 
48 MODEL AEROPLANES 
 
 bamboo. To make the chassis sufficiently 
 stable a piece of bamboo 7^" should be fast- 
 ened from either side of the main chassis struts 
 at the point where the chassis brace on either 
 side meets With the main strut. The ends of 
 this cross brace should be bent in similar fash- 
 ion to the other braces to enable its being 
 fastened easily and permanently. 
 
 For the accommodation of the pontoons two 
 strips of flat steel wire, each 4" in length, 
 should be attached to the ends of the main 
 struts, about one inch from the bottom, the 
 farthest ends should be bent to grip the second 
 spar which joins the pontoons. Note diagram 
 10. 
 
 To further strengthen the chassis a strip of 
 flat steel wire sufficiently long enough should be 
 bent so that %" of the central portion can be 
 securely fastened to the center of the cross 
 brace as shown in diagram 10. The two 
 outer ends should be bent down and are fas- 
 tened to the wires which are attached to the bot- 
 tom ends of the struts. This method of at- 
 
Erwin B. Eiring about to release R. O. G. Model. (Note 
 manner of holding propellers.) Kennith Sedgwick, tractor 
 record holder Milwaukee Model Club. Courtesy Gilbert 
 Counsell. 
 
 
 Waid Carl releasing R. O. G. Model. Courtesy Edward 
 P. Warner. 
 
CONSTRUCTION 49 
 
 taching the forward pontoons enables the con- 
 structor to adjust them to any desired angle 
 and also detach them when not in use. 
 
 A model hydroaeroplane is one of the most 
 interesting types of models and if properly 
 taken care of will afford the constructor many 
 pleasant moments. 
 
 LAUNCHING AN R. O. G. OR MODEL 
 HYDROAEROPLANE 
 
 Although the method of determining the bal- 
 ance of an R. O. G. or a model hydroaeroplane 
 is exactly the same as that of a hand launched 
 model, the manner of launching is somewhat 
 different. Instead of holding the model one 
 hand in the center of the frame and the other at 
 the rear as in the case of the hand launched 
 model, in launching an R. O. G. or hydro, the 
 model should be rested upon the ground or 
 water, as the case may be, with both hands 
 holding tightly to the propellers. Then when 
 about to let the model go release both propellers 
 instantly. If the model has sufficient power 
 
50 MODEL AEROPLANES 
 
 and it has been properly adjusted it will glide 
 over the surface of the ground or water for a 
 short distance, then rise into the air. Should 
 the model fail to rise into the air additional 
 strands of rubber should be added, after which 
 it should be rewound and a second attempt 
 made. 
 
 Should the model fail to respond after the ad- 
 dition of extra rubber, the indications are that 
 something requires further adjustment. Per- 
 haps the pontoons need further elevation if the 
 model is a hydro, or if it be an R. O. G. model 
 the forward wing may require an increase of 
 elevation. In any event the model should be 
 carefully examined and adjustments made 
 where necessary, after which the model should 
 be tested for balance and elevation. If satis- 
 fied with the behavior of the model after test 
 flights have been made, another attempt should 
 be made to launch the model from the ground 
 or water. 
 
 On no account try to fly the model in the 
 house, or see, supposing the model is of the R. 
 
CONSTRUCTION 51 
 
 O. G. type, if it will rise from the dining room 
 floor. This advice may seem unnecessary, but 
 it is not so, for there has been quite a number 
 of instances in which the above has been done, 
 nearly always with disastrous results, not al- 
 ways to the model, more often to something of 
 much greater value. The smashing of win- 
 dows has often resulted from such attempts, 
 but generally speaking pictures are the worst 
 sufferers. It is equally unwise to attempt to 
 fly the model in a garden in which there are 
 numerous obstructions, such as trees and so 
 forth. A wrecked model is very often the re- 
 sult of such experimenting. The safest way to 
 determine the flying ability of any model is to 
 take it out in an open field where its flight is 
 less apt to be interrupted. 
 
WORLD RECORD MODELS 
 
 THE LAUDER DISTANCE AND 
 DURATION MODEL 
 
 AFTER many months of experimentation Mr. 
 Wallace A. Lauder succeeded in producing a 
 model that proved to be one of his most suc- 
 cessful models. But a few years ago flights 
 of 1000 feet with a duration of 60 seconds were 
 considered remarkable. But so rapid has been 
 the development of the rubber strand driven 
 model that to-day it is hardly considered worth 
 while to measure a flight of 1000 feet, espe- 
 cially in contests where models fly over 2500 
 feet or 3537 feet which was the distance flown 
 by Mr. Lauder's model during one of the con- 
 tests of the National Model Aeroplane competi- 
 tion of 1915. Mr. Lauder's model on several 
 occasions made flights of over 3500 feet with a 
 duration in each event of over 195 seconds. It 
 
 is therefore to be remembered that this model 
 
 52 
 

 LAUDER WORLD RECORD MODEL 53 
 
 is both a distance and duration model, both 
 qualities being seldom found in one model. 
 
 Reference to the accompanying drawing 
 will give a clear idea of the constructional de- 
 tails. 
 
 The frame or fuselage consists of two side 
 members 40" in length, of straight grained 
 spruce. At the center each member is of ap- 
 proximately cross section, and is J4" m di- 
 ameter. The members taper to about 3-16" at 
 the ends, the circular cross section being main- 
 tained throughout. The frame is braced by a 
 strip of bamboo of streamline form, extending 
 from one side member to the other, 18" from 
 the apex of the frame. The ends of this frame 
 are bent to run parallel to the side members of 
 the frame where they are secured by binding 
 with silk thread and gluing. Piano wire hooks 
 are also secured to the side members of the 
 frame adjacent the ends of the cross brace, and 
 from these hooks extend wires of steel (No. 2 
 music wire) which run diagonally to the rear 
 brace or propeller spar where they are secured. 
 
54 
 
 MODEL AEROPLANES 
 
 Blank 
 
 Diagram n 
 
LAUDER WORLD RECORD MODEL 55 
 
 The frame is braced further by an upwardly 
 arched strip of bamboo, as shown in diagram 
 1 1, this strip being 2 J^ ? " in height. At the top 
 of this brace are two bronze strips of No. 32 
 gauge brass, one above the other, one on top of 
 the brace and the other below. 
 
 Adjacent the ends of these strips of metal are 
 perforations through which pass bracing wires, 
 one of which wires run to the front of the 
 frame where a hook is mounted for its recep- 
 tion, and the other two wires extend to the rear 
 of the frame where they are secured to the pro- 
 peller brace. The propeller brace consists of 
 a strip of streamlined spruce n^4" in length, 
 the propellers being at an angle, thus clearance 
 is allowed J4" wide at the center, tapering to 
 3-16" at the ends. The ends of the propeller 
 brace extend out one inch from the side mem- 
 bers of the frame, to allow room for the rubber 
 strands to be used as motive power. In order 
 to avoid slotting the ends of the side members 
 of the frame so that the propeller brace can be 
 secured therein, thin strips of bamboo are se- 
 
5 6 MODEL AEROPLANES 
 
 cured above and below the end of each side 
 member, by binding with silk thread and glu- 
 ing, the space between these bamboo strips be- 
 ing utilized for the brace which is securely 
 bound and glued therein. The propeller bear- 
 ings consist of strips of very thin bronze (No. 
 32 gauge), about 3-16" in width, bent over 
 $/%" strips of German silver tubing, the tubing 
 being soldered to the bronze strips and the 
 propeller brace, which fits between the up- 
 per and lower portions of the bronze strips, is 
 securely bound and glued thereto. 
 
 The propellers are cut from solid blocks of 
 pine, and are 12" in diameter. The blade, at 
 its widest portion, measures iJMs". The blades 
 are cut very thin, and in order to save weight, 
 they are not shellacked or painted. 
 
 The propeller shafts are of piano wire (No. 
 20 size) to fit the tubing used in the bearings, 
 pass through the propellers and are bent over 
 on the outer side to prevent turning. A few 
 small bronze washers are interposed between 
 the propellers and the outer ends of the tubing 
 
Wallace A. Lauder distance and duration model 
 
 Wallace A. Lander R. O. G. Model 
 
LAUDER WORLD RECORD MODEL 57 
 
 to minimize friction when the propellers are re- 
 volving. Twelve strands of rubber are used 
 for each propeller, the rubber being j" flat. 
 
 The wings are both double surfaced, and are 
 of the swept back type. The span of the main 
 wing is 28%", with a chord of 6y 2 ". The ele- 
 vator has a span of 15" with a chord of 4?4". 
 The main wing has eleven double ribs, these 
 ribs being built up on mean beams of spruce 
 I- 1 6" x 3-16", the front beam being placed i J4" 
 from the entering edge, and the second beam 
 being 2" back from the front beam. The enter- 
 ing and trailing edges are formed from a sin- 
 gle strip of thin split bamboo, all the joints be- 
 ing made by binding with thin silk and gluing. 
 
 The elevator is constructed in like manner, 
 except that it only has seven ribs, and the meas- 
 urements are as above set forth. Both planes 
 are covered with goldbeater's skin, sometimes 
 known as "Zephyr" skin, which is first glued in 
 place and then steamed, which tightens the 
 same on the plane, and given a coat of prepara- 
 tion used for this purpose. 
 
THE HITTLE WORLD RECORD 
 MODEL 
 
 (SINGLE TRACTOR MONOPLANE, 116 SECONDS 
 DURATION RISING FROM WATER) 
 
 THE Kittle World record model hydroaero- 
 plane, designed and constructed by Mr. Lindsay 
 Kittle of the Illinois Model Aero Club, is per- 
 haps one of the most interesting types of models 
 yet produced. The establishing of this record 
 illustrates the value of careful designing and 
 construction and offers to the beginner an ex- 
 ample which might be followed if good results 
 are sought. In having broken the world's 
 model hydroaeroplane record with a tractor 
 type model Mr. Kittle accomplished a feat of 
 twofold importance. First, in having ad- 
 vanced the possibilities of the tractor model, 
 and, second, in illustrating the value of scien- 
 tific construction. The previous record for 
 
 58 
 
KITTLE WORLD RECORD MODEL 59 
 
 this type of model has been but 29 seconds, just 
 one-fourth of the duration made by Mr. Hit- 
 tie's model. 
 
 Mr. Hittle's model shows many new and 
 original features not hitherto combined on any 
 one model. Note diagram 12. The model is 
 of extremely light weight, weighing complete 
 but 1.75 ounces. The floats and their attach- 
 ments have been so designed as to offer the 
 least possible wind resistance. In fact every 
 possible method was utilized in order to cut 
 down weight and resistance on every part of 
 the model. As a result of this doing away with 
 resistance an excellent gliding ratio of 8^4 to I 
 has been obtained. 
 
 For the motor base of the model a single stick 
 of white pine %" deep and 45" in length is used. 
 On the front end the bearing for the propeller 
 is bound with silk thread and a waterproof glue 
 of the constructor's own composition being 
 used to hold it secure. For the bearing a small 
 light weight forging somewhat in the shape of 
 the letter "L" is used, this being made stream- 
 
60 MODEL AEROPLANES 
 
 line. At the rear end of the motor base is at- 
 tached a piano wire hook for the rubber. The 
 stabilizer consisting of a segment of a circle 
 measuring 12" x 8" is attached to the under 
 side of the motor base. The rudder measuring 
 3^" X 3^" is attached to the stabilizer at the 
 rear of the motor base. 
 
 The wing is built up of two beams of white 
 pine with ribs and tips of bamboo and has an 
 area of 215 square inches 
 
 The wing which has a total span of 43" and 
 a chord of 5^" is built up of two beams of 
 white pine with ribs and tips of bamboo and 
 has a total area of 215 square inches. The 
 wing is given a small dihedral and the wing tips 
 are slightly upturned at the rear. 
 
 The trailing edge is longer than the entering 
 edge the ribs being placed somewhat oblique in 
 order to secure an even spacing. The wing is 
 attached to the frame by two small bamboo 
 clips which hold it rigidly and permit easy ad- 
 justment and is set at an angle of about 4 
 degrees with the line of thrust. Both the 
 
KITTLE WORLD RECORD MODEL 61 
 
 PlatvVietS. 
 
 Diagram 12 
 
62 MODEL AEROPLANES 
 
 floats which take practically the whole weight 
 of the machine are situated directly under the 
 wing just far enough behind the center of 
 gravity to prevent the model from tipping back- 
 ward. These floats are attached to the motor 
 base by means of streamlined bamboo struts. 
 Bamboo is also used in the construction of the 
 float frames. A single float of triangular sec- 
 tions is situated just behind the propeller. The 
 entire weight of the floats and their attach- 
 ments is but .23 ounces. 
 
 The propeller which consists of four blades 
 is built up of two propellers joined together at 
 the hubs and securely glued, the completed pro- 
 peller having a diameter of 10" with a theoreti- 
 cal pitch of 14". The blades are fairly nar- 
 row, tapering almost to a point at the tips. 
 The propeller is driven by five strands of %6th" 
 strip rubber at about 760 r. p. m. when the 
 model is in flight. At the time when the model 
 made its record flight of 116 seconds the rubber 
 was given 1500 turns which is not the maxi- 
 mum number of turns. At other times the 
 
KITTLE WORLD RECORD MOQEL 63 
 
 model has flown satisfactorily with less turns 
 of the rubber. While in the air the model flies 
 very slow and stable notwithstanding its light 
 weight and large surface. On three occasions 
 the model has made durations of approximately 
 90 seconds which rather dispenses the possi- 
 bility of its being termed a freak. 
 
THE LA TOUR FLYING BOAT 
 
 ONE of the most notable results of the Na- 
 tional Model Aeroplane Competition of 1915 
 was the establishing of a new world's record 
 for flying boats. Considering that the model 
 flying boat is a difficult type of model to con- 
 struct and fly, the establishing of this new 
 world record of 43 seconds is remarkable. 
 Credit for this performance is due Mr. Robert 
 La Tour of the Pacific Northwest Model Aero 
 Club, who designed, constructed and flew the 
 model flying boat which is herewith described 
 and illustrated. Diagram 13. 
 
 The frame is made of laminated spruce 40" 
 in length, made of two strips glued together. 
 They are %"x%" at the center tapering to 
 %e" x %" at the ends. The cross braces are of 
 split bamboo and are fastened to the frame side 
 members by bringing them to a wedge at the 
 ends and then inserting them into slots in the 
 
 64 
 
LA TOUR FLYING BOAT 65 
 
 sides of the frame side members and are finally 
 drilled and bound to the latter. The rear brace 
 is of streamlined spruce }4"x j"; this butts 
 against the frame side members and is bound 
 to them. The propeller accommodations are 
 made of brass. 
 
 The propellers are 10" in diameter with a 19" 
 pitch. These are carved from a block of 
 Alaska cedar i%" wide by ft" thick. Of 
 course the propellers may also be made from 
 white pine. To turn the propellers 15 strands 
 of Y%" flat rubber are used. 
 
 Bamboo about VIG" square is used to obtain 
 the outline of the wings. The main wing has 
 a span of 33" with a chord of 5 T / 2 ". Split bam- 
 boo is used for the making of the 9 ribs. The 
 wing spar or brace is of spruce %e" x %" and is 
 fastened below the ribs as illustrated in dia- 
 gram 13. The elevator is constructed in like 
 manner but has a span of only I7"x424" and 
 has only 5 ribs. A block %" high is used for 
 elevation. Both wings have a camber of J4" 
 and are covered on the upper side with silk 
 
66 
 
 MODEL AEROPLANES 
 
 Diagram 13 
 
LA TOUR FLYING BOAT 67 
 
 doped with a special varnish and a few coats of 
 white shellac. 
 
 The boat is 20" long, 3" in width and shaped 
 as shown. The slip is ^2" deep and is located 
 7" from the bow. The rear end is brought 
 down steeply to avoid the drag of the water on 
 this point when the boat is leaving the surface 
 of the water. Spruce %4ths of an inch thick is 
 used for the making of the sides, but the cross 
 bracing is of slightly heavier material, there be- 
 ing six braces used throughout. The rear 
 brace is much heavier in order to withstand the 
 pull of the covering and to receive the ends of 
 the wire connections. The outriggers or bal- 
 ancing pontoons are constructed of the same 
 material as that of the boat and are held to- 
 gether by a spruce beam 18" long, y 2 n wide by 
 %e" thick, streamlined. This beam is fastened 
 to the boat by means of three brads to permit 
 changing if necessary. The lower edges of the 
 outriggers should clear the water abo,ut J^" be- 
 fore the steps on the boat leave the water. The 
 boat and outriggers are covered with silk, 
 
68 MODEL AEROPLANES 
 
 shrunk with a special solution and then coated 
 several times with white shellac. It is a good 
 plan to shellac the interior walls of the boat and 
 pontoons before covering to prevent them from 
 losing their form by becoming soft from the 
 influence of water in the case of a puncture. 
 
 The boat is connected to the frame at its 
 front by two steel wires, their ends being in- 
 serted into the cross members of the boat, and 
 then brought up along the sides, crossed and 
 then bound to the frame. A similar pair of 
 connecting wires are used to connect the rear 
 end of the boat to the rear end of the frame. 
 A U-shaped wire is bound to the outrigger 
 beam and frame. A single diagonal strip of 
 bamboo is also fastened to the outrigger beam 
 with a brad, its upper end being bound to the 
 cross bracing of the frame, making a very solid 
 connection. 
 
 Under ideal weather conditions this model 
 will fly on 12 strands of rubber with the possi- 
 bility of a better duration than has been made. 
 But, however, with 15 strands the model will 
 
LA TOUR FLYING BOAT 69 
 
 rise at every attempt. More rubber, however, 
 causes the bow of the boat to nose under and to 
 accommodate this increase of power the boat 
 should be lengthened. 
 
THE COOK NO. 42 WORLD 
 RECORD MODEL 
 
 (TWIN PROPELLER HYDROAEROPLANE, IOO.6 
 SECONDS RISING FROM WATER) 
 
 DURING the National Model Aeroplane Com- 
 petition of 1915 held under the auspices of the 
 Aero Club of America, a number of new world 
 records were established, one of which was for 
 twin propeller hydroaeroplanes. The credit 
 for this record is due Mr. Ellis C. Cook of the 
 Illinois Model Aero Club, who succeeded in 
 getting his model hydroaeroplane which by 
 the way is a rather difficult type of model to 
 operate to rise from the water and remain in 
 the air for a duration of 100.6 seconds. This 
 model is of the common A frame design with 
 the floats or pontoons arranged in the familiar 
 fashion, two forward and one aft. The model 
 is fairly light, weighing, when complete, 3.33 
 
 70 
 
THE COOK NO. 42 MODEL 71 
 
 ounces, ^ ounce of which is made up in rubber 
 strands for motive power. Diagram 14. 
 
 The frame is made of two sticks of white 
 pine for side members, each member measuring 
 $8 1 A" in length, 5 /i 6 " in depth, by H" in width. 
 These are cut to taper toward the ends where 
 they are only Vs" in width by %e" in depth in the 
 front and rear respectively. Three "X" strips 
 of streamlined bamboo measuring %e" in width 
 by %4ths of an inch in depth, are used for brac- 
 ing the frame between the front and rear and 
 are arranged as shown in diagram 14. The 
 propeller bearings are of small streamlined 
 forgings of light weight, and are bound to the 
 rear end of each side member first by gluing, 
 then binding around with thread. The front 
 hook is made of No. 16 piano wire and is bound 
 to the frame as shown in diagram 14. The 
 chassis which holds the floats or pontoons is 
 made of %2" bamboo bent to shape and bound 
 to the frame members. By the use of rubber 
 strands the floats are attached to the chassis; 
 
72 MODEL AEROPLANES 
 
 the forward ones being attached so that angle 
 may be adjusted. 
 
 The main wing has a span of 36" and a 
 chord of 5" and is constructed of two white 
 pine beams each 39" long, with bamboo wing 
 tips. The ribs, seven in number, are also made 
 of bamboo and are spaced along the edges of 
 the wing at a distance of 4^" apart. The 
 "elevator" or front wing has a span of 14" and 
 a chord of 3)4"> the framework of which is 
 made entirely of bamboo. The entering edge 
 of this wing is given a slightly greater dihedral 
 so that the angle of incidence at the tips is 
 greater than at the center. By this method the 
 added incidence in the front wing is obtained. 
 By the use of rubber bands both wings are at- 
 tached to the frame. 
 
 The two forward floats are spaced eight in- 
 ches apart and are of the stepped type, the step 
 being 3%" from the front and has a depth 
 of y%". These two floats are separated by 
 two bamboo strips as shown in the diagram, 
 
THE COOK NO. 42 MODEL 73 
 
 CooJC Kydro. 
 
 Diagram 14 
 
74 MODEL AEROPLANES 
 
 which are tied to the rounded portion of 
 the under carriage by small rubber bands. By 
 the sliding of these strips back and forth the 
 necessary angle of the floats may be obtained to 
 suit conditions. The floats are built up with 
 two thin pieces of white pine for sides, sepa- 
 rated by small pieces of wood about one-half 
 the size of a match in cross section. Chiffon 
 veiling which is used for the covering of the 
 wings, is also used for the covering of the 
 floats, after which it is covered with a special 
 preparation to render both the wings and the 
 floats air and water-tight. 
 
 The two ten-inch propellers with which the 
 model is fitted have a theoretical pitch of twelve 
 and one-half inches. The propellers are 
 carved from blanks one-half inch thick, the 
 blades of the completed propellers having a 
 maximum width of one inch at a radius of 
 three inches. The propeller shafts are made 
 from No. 16 piano wire and have small wash- 
 ers for bearings. Each propeller is driven by 
 three strands of %" strip elastic. The rub- 
 
THE COOK NO. 42 MODEL 75 
 
 her is given 1700 to 1750 turns and revolves the 
 propellers at 1150-1200 r. p. m., when the 
 model is in flight. 
 
 The model usually runs over the surface of 
 the water for a distance of from two to three 
 feet before it rises, after which it climbs at a 
 very steep angle to the necessary altitude. 
 The model seems, when in flight, to be slightly 
 overpowered but this is misleading. The rub- 
 bers usually unwind in from 85 to 90 seconds. 
 On four out of six flights this model has made 
 a duration of between 98 and 100 seconds 
 which is rather unusual for a model of this 
 type. 
 
THE RUDY FUNK DURATION 
 MODEL 
 
 OF the many different types of duration 
 models that have made their appearance dur- 
 ing the year of 1915 perhaps the model de- 
 scribed herewith, constructed and flown by 
 Mr. Rudolph Funk, of the Aero Science Club, 
 was one of the most successful. Unlike most 
 models the propellers of this model are bent 
 and not cut. This model made its appearance 
 during the latter part of 1915, on several oc- 
 casions having flown for over 100 seconds dur- 
 ation. Diagram 15. 
 
 While retaining the important characteristics 
 of his standard model, slight changes have been 
 made. Instead of the usual wire for the con- 
 struction of the frame of the wings, bamboo is 
 used in its place for lightness and strength. 
 The wing frames are single surfaced, China 
 
 76 
 
RUDY FUNK MODEL 77 
 
 silk being used for covering. The "dope" 
 which is used to render the silk airtight is made 
 by dissolving celluloid in banana oil. This in 
 turn is applied to the silk with a soft brush. 
 
 The camber of the main wing is 24" at 
 the center, with a slight reduction towards 
 the negative tips; it also has a dihedral angle 
 of 2 degrees. The main beam, which is secured 
 to the under side of the frame for rigidness, is 
 of spruce i" by 5-64", tapering to 4" x 5-64". 
 The ribs for the main wing and small wing or 
 "elevator" are cut from solid pieces of bamboo 
 3-16" thick by J4" wide. These pieces of bam- 
 boo are first bent to the proper camber and are 
 then cut into strips each 1-16" wide. The ribs 
 are next tapered to a V at the bottom, toward 
 the trailing edge, as shown in diagram 15, and 
 also toward the entering edge. To accommo- 
 date the entering and trailing edges of the 
 frame, each rib is slit slightly at both ends. 
 Both edges of the frame are then inserted in the 
 slots at the ends of the ribs and bound around 
 with silk thread. 
 
MODEL AEROPLANES 
 
 Diagram 15 
 
RUDY FUNK MODEL 79 
 
 The frame is composed of two sticks of silver 
 spruce 38" in length, 5-16" x 3-16", tapering to 
 J4" x 5-32", held apart by a streamline bamboo 
 cross brace in the center. An additional brace 
 of bamboo is securely fastened across the frame 
 toward the front. The propeller brace con- 
 sists of a streamline-cut piece of bamboo 12^2 " 
 in length by y" in width at the center, tapering 
 to y\" toward the ends. The propeller brace 
 is inserted in slots cut in the rear ends of the 
 frame members, then bound and glued. 
 
 The propellers are bent from birch veneer, 
 the bending being done over an alcohol flame 
 as illustrated in diagram 15. But first of all 
 the blades are cut to shape, sandpapered and 
 finished before they are bent. As shown in the 
 drawing a slot is filed in the hub of each blade 
 to enable the propeller shaft to pass through 
 when both have been glued together. The 
 blades are then glued and bound together, first 
 by placing a piece of wire in the slots to insure 
 their being centered and also to prevent their 
 being filled with glue. After this has been done 
 
80 MODEL AEROPLANES 
 
 each propeller is given three coats of the same 
 dope as is used on the wings. 
 
 The propeller bearings are turned out of 
 i -32" bronze tubing, the length of each bearing 
 being 1/2". Steel washers are slipped over 
 the propeller shaft, between the bearing and 
 propeller to insure smooth running. The pro- 
 peller shafts are made from steel hatpins which 
 are heated at both ends, one end of which is 
 bent into a loop to receive the rubber strands, 
 the other end being bent around the hub of the 
 propeller to prevent the shaft from slipping 
 during the unwinding of the rubbers. Two 
 strips of brass, each J4"x 2", are bent around 
 the one-half inch bearing and soldered. The 
 brass strips are then glued and bound onto the 
 ends of the propeller brace as shown in diagram 
 
Rudy Funk speed model 
 
 Schober compressed air driven monoplane. McMahon 
 compressed air driven tractor (right) 
 
THE ALSON H. WHEELER WORLD 
 RECORD MODEL 
 
 (TWIN PUSHER BIPLANE 143 SEC. DURATION 
 RISING FROM THE GROUND) 
 
 SINCE the beginning of model flying very 
 little attention has been paid to the model bi- 
 plane. Practically all records are held by 
 model aeroplanes of the monoplane type. 
 With this fact in view, the record established 
 by Mr. Wheeler with his Twin Pusher Biplane 
 is extraordinary, in so far as it surpasses many 
 of the monoplane records. This model is a 
 very slow flyer, and has excellent gliding abil- 
 ity. At the time when this model flew and 
 broke the world's record, the greater portion of 
 the flight consisted of a beautiful glide of 86 
 seconds' duration, after the power gave out, 
 making it possible for the model to remain in 
 , the air for a duration of 143 seconds. 
 
 81 
 
82 MODEL AEROPLANES 
 
 The frame consists of two I-beams, each 
 48" in length, running parallel, and spaced by 
 cross pieces, each piece iij^" long. The 
 bearing blocks used made it possible for the 
 propellers to clear by one-half inch. Two 12" 
 expanding pitch racing propellers are used 
 and these are mounted on ball bearing shafts. 
 The main upper plane has a span of 34" with 
 a chord of 5", the lower plane being 26" by 5". 
 The elevator consists of two planes, each meas- 
 uring 14" by 5". Cork wheels are used, each 
 being one inch in diameter. For motive power 
 one-eighth inch flat rubber is used, this being 
 coated with glycerine to prevent sticking. 
 
Alson H. Wheeler twin pusher Biplane 
 
 C V. Obst tractor model 
 
A SIMPLE COMPRESSED AIR MOTOR 
 
 DURING the past few years model flyers in 
 America have shown a tendency toward the 
 adoption of compressed air motors for use in 
 connection with model aeroplanes. Hitherto, 
 England has been the home of the compressed 
 air motor, where a great deal of experimenting 
 has been carried on, to a considerable degree 
 of success. Flights of over 40 seconds have 
 been made with models in which compressed 
 air power plants were used. But, however, the 
 desire on the part of a large majority of model 
 flyers in America to build scientific models, that 
 is, models more closely resembling large ma- 
 chines, has made it necessary to find a more 
 suitable means of propulsion; rubber strands 
 being unsatisfactory for such purposes. Many 
 different types of compressed air motors have 
 made their appearance during the past few 
 years, among which the two cylinder opposed 
 
 83 
 
84 MODEL AEROPLANES 
 
 type is very favorably looked upon, because it 
 is perhaps one of the easiest to construct. 
 
 To make a simple two cylinder opposed com- 
 pressed air power plant, as illustrated in Figure 
 i of diagram 16, it is not necessary that the 
 builder be in possession of a machine shop. A 
 file, drill, small gas blow torch and a small vise 
 comprise the principal tools for the making of 
 the motor. 
 
 The first things needed in the making of this 
 motor are cylinders. For the making of the 
 cylinders two fishing rod ferrules, known as 
 female ferrules, are required. And for the 
 heads of the cylinders, two male ferrules are 
 required. Such ferrules can be secured .at 
 most any sporting goods store. The female 
 ferrules should be filed down to a length of 
 2", cut down on one side a distance of y^ 
 of the diameter, then cut in from the end as 
 shown in Figure 7. When this has been done 
 the two male ferrules should be cut off a dis- 
 tance of %" from the top as shown in Figure 
 7a, to serve as heads for the cylinders. A hole 
 
SIMPLE COMPRESSED AIR MOTOR 85 
 
 Flax, fc&S tf /%oor. 
 
 Diagram 16 
 
86 MODEL AEROPLANES 
 
 y%" in diameter should be drilled in the center 
 of each head so as to enable the connecting of 
 the intake pipes. By the use of soft wire solder 
 the heads should be soldered into the ends of the 
 cylinders as shown in Figure id. 
 
 The pistons should now be made ; for this pur- 
 pose two additional male ferrules are required. 
 These should be made to operate freely within 
 the cylinders by twisting them in a rag which 
 has been saturated with oil and upon which has 
 been shaken fine powdered emery. When they 
 have been made to operate freely they should 
 be cut down one-half inch from the closed end 
 as shown in Figure 5a. For the connecting 
 rods, 2 pieces of brass tubing, each &" in 
 diameter by ij4" long, are required, and, as 
 illustrated in Figure 6, should be flattened out 
 at either end and through each end a hole 3-32" 
 in diameter should be drilled. For the con- 
 necting of the piston rods to the pistons, studs 
 are required, and these should be cut from a 
 piece of brass rod }4" in diameter by ^2" 
 in length. As two studs are necessary, one 
 
SIMPLE COMPRESSED AIR MOTOR 87 
 
 for each piston, this piece should be cut in 
 half, after which each piece should be filed in 
 at one end deep enough to receive the end of 
 the connecting rod. Before soldering the 
 studs to the heads of the pistons, however, 
 the connecting rods should be joined to the 
 studs by the use of a steel pin which is passed 
 through the stud and connecting . rod, after 
 which the ends of the pin are flattened, to keep 
 it in position as shown in Figure 5a. 
 
 For the outside valve mechanism and also to 
 serve in the capacity as a bearing for the crank- 
 shaft, a piece of brass tubing ^4" in diameter 
 by I 1 /*" long is required. Into this should be 
 drillpd three holes, each y%" in diameter, and 
 each y*" apart as shown in Figure 4. Next, 
 for the valve shaft and also propeller accommo- 
 dation, secure a piece of 3-16" drill rod 2" long. 
 On the left hand side of the valve shaft, as 
 shown in Figure 3, a cut 1-32" deep by J4" in 
 length is made i" from the end. Another cut 
 of the same dimensions is made on the right 
 side only; this cut is made at a distance of %" 
 from the stud end. 
 
88 MODEL AEROPLANES 
 
 As shown in Figure if, the crank throw con- 
 sists of a flat piece of steel, 3-32" thick, ^" in 
 length by J4" in width. At each end of the 
 crank throw a hole 3-16" in diameter should be 
 drilled, the holes to be one-half inch apart. 
 Into one hole a piece of steel drill rod 3-32" in 
 diameter by *4" long is soldered, to which the 
 connecting rods are mounted, as shown in Fig- 
 ure i f . Into the other hole the stud end of the 
 crank throw is soldered. 
 
 Before making the tank it is most desirable 
 to assemble the parts of the motor, and this 
 may be done by first fitting the pistons into the 
 cylinders as shown in Figure i-b, after which 
 the cylinders should be lapped one over the 
 other and soldered as shown in Figure i-a. 
 When this has been done a hole one-fourth of 
 an inch in diameter should be drilled half way 
 between the ends of the cylinders, and into 
 this hole should be soldered one end of the valve 
 casing shown in Figure 4. For the inlet pipes 
 as shown in Figure i-c secure two pieces of 
 y%" brass tubing and after heating until soft, 
 
Schober pusher type compressed air driven monoplane 
 
 
 
 Schober compressed air driven biplane 
 
SIMPLE COMPRESSED AIR MOTOR 89 
 
 bend both to a shape similar to that shown in 
 Figure i-c. When this has been done solder 
 one end to the end of the cylinder and the other 
 in the second hole of the valve shaft casing. 
 The valve shaft should now be inserted in the 
 valve shaft casing and the connecting rods 
 sprung onto the crank throw as shown in Fig- 
 ure i-d. To loosen up the parts of the motor 
 which have just been assembled it should be 
 filled with oil and by tightly holding the crank- 
 shaft in the jaws of a drill the motor can be 
 worked for a few minutes. 
 
 The tank is made from a sheet of brass or 
 copper foil 15" long by i-ioo" thick. This 
 is made in the form of a cylinder, the edges 
 of which are soldered together as shown in 
 Figure 2*. Sometimes this seam is riveted 
 every one-half inch to increase its strength, 
 but in most cases solder is all that is required 
 to hold the edges together. For the caps, or 
 ends, the tops of two small oil cans are used, 
 each can measuring 2^/2" in diameter. To 
 complete the caps two discs of metal should be 
 
90 MODEL AEROPLANES 
 
 soldered over the ends of the cans where for- 
 merly the spouts were inserted, the bottoms of 
 the cans having been removed. The bottom 
 edges of the cans should be soldered to the 
 ends of the tank as shown in Figure 2. Into 
 one end of the completed tank a hole large 
 enough to receive an ordinary bicycle air valve 
 should be drilled. Figure 2. Another hole is 
 drilled into the other end of the tank, into which 
 is soldered a small gas cock to act as a valve. 
 Figure 2. This should be filed down where 
 necessary, to eliminate unnecessary weight. 
 To connect the tank with the motor, a piece of 
 ]/%" brass tubing 3" long is required, the ends 
 of which are soldered into the holes in the valve 
 shaft casing nearest the cylinders, as shown in 
 Figure i ee. As shown in Figure i ee, a hole 
 y%" in diameter is drilled in one side of this 
 piece, but not through, in the end nearest the 
 tank. Another piece of brass tubing J^" in 
 diameter is required to connect the tank with 
 the motor, one end of which is soldered to the 
 cock in the tank, the other in the hole in the 
 
SIMPLE COMPRESSED AIR MOTOR 91 
 
 pipe which leads from the motor to the tank, 
 illustrated in Figure I ee, thus completing the 
 motor. 
 
 In conclusion it is suggested that the builder 
 exercise careful judgment in both the making 
 and assembling of the different parts of the 
 motor in order to avoid unnecessary trouble 
 and secure satisfactory results. After having 
 constructed a motor as has just been described, 
 the constructor may find it to his desire to con- 
 struct a different type of motor for experi- 
 mental purposes. The constructor therefore 
 may find the descriptions of satisfactory com- 
 pressed air motors in the following paragraphs 
 of suggestive value. 
 
COMPRESSED AIR MODELS 
 
 THE MC MAHON COMPRESSED AIR DRIVEN 
 MONOPLANE 
 
 ONE of the latest developments in the field 
 of model flying is the McMahon compressed air 
 driven monoplane. This model was built to 
 be used as either a tractor or pusher, but in view 
 of its ability to balance more easily as a pusher 
 most of the experiments have been carried out 
 on this machine as a pusher. The machine in 
 itself is simple and inexpensive to construct, the 
 chief portion of the expense being involved in 
 the making of the motor. By using the ma- 
 chine as a pusher a great deal of protection is 
 afforded both the propeller and motor, and this 
 protection helps to avoid damaging the pro- 
 peller or motor, which would mean an addi- 
 tional expenditure for repairs, thus minimizing 
 
 the cost of flying the model. 
 
 92 
 
COMPRESSED AIR MODELS 93 
 
 The frame has been made to accommodate 
 both the tank and motor, and this is done by 
 using two 30" strips of spruce, each J4" wide 
 by y" deep, laid side by side, a distance of 
 three inches apart, up to within 10" of the 
 front, as shown in the accompanying photo- 
 graph. No braces are used on the frame, as 
 the tank, when securely fastened between the 
 frame, acts in that capacity. 
 
 The wings are made in two sections, each 
 section measuring 24" in span by 8" in chord, 
 consisting of two main spars, 3-16" in diameter, 
 one for the entering edge and one for the trail- 
 ing edge. To these edges, at a distance of 
 three inches apart, are attached bamboo ribs, 
 1 8 in all, each measuring 8" in length by l /%" 
 in width by 1-16" thick. The wings are round 
 at the tips, and have a camber of approximately 
 one-half inch, but they are not set at an angle 
 of incidence. Light China silk is used for 
 covering and after being glued over the top of 
 the wing frame is given two coats of dope to 
 shrink and fill the pores of the fabric. A good 
 
94 MODEL AEROPLANES 
 
 "dope" for the purpose can be made from cel- 
 luloid dissolved in banana oil. The wing sec- 
 tions are attached to the frame and braced by 
 light wire. The forward wing or "elevator" is 
 made in the same manner as the main wing, but 
 should measure only 18" x 3". Instead of be- 
 ing made in two sections as the main wing, the 
 forward wing is made in one piece. 
 
 The chassis is made by forming two V struts 
 from strong steel wire sufficiently large enough 
 so that when they are attached to the frame of 
 the model the forward part will be 9" above the 
 ground. One V strut is securely fastened to 
 either side of the frame, at a distance of 8" 
 from the front. A 7" axle is fastened to the 
 ends of these struts. On the axle are mounted 
 two light wheels, each about 2" in diameter. 
 The chassis is braced by light piano wire. 
 
 The rear skid is made in the same manner as 
 the forward skid, only that the ends of the 
 struts are brought together and a wheel i inch 
 in diameter is mounted at the bottom ends by 
 means of a short axle. The struts are not 
 
John McMahon and his compressed air driven 
 monoplane 
 
 Frank Schober preparing his model for flight. 
 Gauge to determine pressure of air may be 
 seen in photograph 
 
COMPRESSED AIR MODELS 95 
 
 more than 7^" long, thus allowing a slight 
 angle to the machine when it is resting upon 
 the ground. 
 
 The machine complete does not weigh over 
 7 ounces. The power plant used in connection 
 with this model is of the two cylinder opposed 
 motor type, with tank such as has just been 
 described in the foregoing chapter. 
 
 The tank is mounted in the frame by drilling 
 a 1-16" hole through either end of the tank, 
 through which a drill rod of this diameter can 
 be inserted. About %ths of the drill rod 
 should extend out on each side of the tank, to 
 permit the fastening of the tank to the frame 
 side members. This method of mounting the 
 tank serves two purposes to a satisfactory de- 
 gree. First, it permits secure fastening; sec- 
 ond, as the rods are passed through the side and 
 cap of the tank they help materially in prevent- 
 ing the caps from being blown off in the event 
 of excessive pressure. 
 
THE MCMAHON COMPRESSED AIR DRIVEN 
 BIPLANE 
 
 IN the McMahon model we find a very satis- 
 factory type of compressed air driven model. 
 On several occasions this model has made 
 flights of over 200 feet with a duration of be- 
 tween 10 and 15 secouds, and the indications 
 are that by the use of a more powerful motor 
 the model can be made to fly a greater distance, 
 with a corresponding increase of duration. 
 The motor used in connection with the model 
 is of the two cylinder opposed type, such as 
 described in the foregoing paragraphs. The 
 tank, however, is somewhat different in design 
 from that just described, it having been made 
 of 28 gauge sheet bronze, riveted every one- 
 half inch. The two long bolts that hold the 
 steel caps on either end of the tank also serve as 
 attachments for the spars that hold the tank to 
 the engine bed, as shown in diagram 18. The 
 tank has been satisfactorily charged to a pres- 
 
 96 
 
COMPRESSED AIR MODELS 97 
 
 sure of 200 Ibs. per square inch, but only a pres- 
 sure of 150 Ibs. is necessary to operate the 
 motor. The tank measures 10" in length by 
 3" in diameter and weighs 7 ounces. 
 
 The wings of this machine are single sur- 
 faced and covered with fiber paper. The top 
 wing measures 42" in span by 6" in chord. 
 The lower wing is 24" by 6". The wings have 
 a total surface of 396 square inches and are 
 built up of two 3-16" dowel sticks, flattened to 
 streamline shape. Only two sets of uprights 
 separate the wings, thus adding to the stream- 
 line appearance of the machine. 
 
 Both tail and rudder are double surfaced and 
 are built entirely of bamboo for lightness, 
 the tail being made in the form of a half cir- 
 cle measuring 12" by 8". Steel wire is used 
 on the construction of the landing chassis, the 
 chassis being so designed as to render it capable 
 of withstanding the most violent shock that it 
 may possibly receive in landing. The propeller 
 used in connection with the model is 14" in di- 
 ameter and has an approximate pitch of 18". 
 
MODEL AEROPLANES 
 
 PI**.. 
 
 /f^ 
 
 \l 
 
 fr 
 
 Diagram 17 
 
COMPRESSED AIR MOTORS 
 
 THE WISE COMPRESSED AIR MOTOR 
 
 ALTHOUGH of peculiar construction, the 
 Wise rotary compressed air motor offers a very 
 interesting design from a viewpoint of ingenu- 
 ity. This motor embodies a number of novel 
 features not hitherto employed in the construc- 
 tion of compressed air motors, and in view of 
 the fact that the majority of compressed air 
 motors are made on the principle of the opposed 
 type, this motor suggests many possibilities for 
 the rotary type motor. 
 
 The motor consists of five cylinders and 
 weighs four ounces, including the propeller and 
 mounting frame. On a pressure of 15 Ibs. the 
 motor will revolve at a speed of 1000 r.p.m. 
 The connecting rods are fastened to the crank- 
 shaft by means of segments and are held by 
 two rings, making it possible to remove any one 
 
 99 
 
ioo MODEL AEROPLANES 
 
 piston without disturbing the others. This is 
 done by simply removing a nut and one ring. 
 The crank case is made from seamless brass 
 tubing, into which the cylinders are brazed. 
 The valve cage and cylinder heads are also 
 turned separately and brazed. One ring only 
 is used in connection with the pistons. The 
 cylinders have a bore of 11-32", with a piston 
 stroke of 7-16". In view of the fact that pull 
 rods show a greater tendency to overcome cen- 
 trifugal force, they are used instead of push 
 rods to operate the valves. The crankshaft has 
 but one post, which is uncovered in turn by each 
 inlet pipe as the motor revolves. The "over- 
 hang" method is used to mount this motor to 
 the model. With the exception of the valve 
 springs, the entire motor, including the mount- 
 ing frame and tank, is made of brass. 
 
 THE SCHOBER-FUNK COMPRESSED AIR MOTOR 
 
 Two of the most enthusiastic advocates of 
 the compressed air motor for use in model aero- 
 planes are Messrs. Frank Schober and Rudolph 
 
COMPRESSED 
 
 Funk, both members of the Aero Science Club. 
 For a number of months both these gentlemen 
 have experimented with compressed air motors 
 of various designs, until they finally produced 
 what is perhaps one of the most satisfactory 
 rotary motors now in use, from a standpoint of 
 simplicity and results. 
 
 As can be seen from the accompanying illus- 
 tration, this little engine is remarkably simple 
 in appearance. The motor complete, with 
 equipment, weighs at the most but 14 ounces. 
 The cylinders, three in all, are stamped from 
 brass shells for strength and lightness. The 
 pistons are made from ebony fiber. The cylin- 
 ders have a bore of jH$", with a piston stroke 
 of y^". The crank case is built up from 
 a small piece of brass tubing and is drilled 
 out for lightness. The crankshaft is hollow, 
 and is supported at the rear by a special bear- 
 ing which acts as a rotary valve, admitting the 
 intake through the crankshaft and permitting 
 the exhaust to escape through a specially con- 
 structed bearing. 
 
"':i MODEL AEROPLANES 
 
 The tank is constructed of 30 gauge sheet 
 bronze, wire wound, and fitted at the ends with 
 spun brass caps. The actual weight of the 
 engine alone is 2^/2 ounces, the tank and fittings 
 weighing n l /2 ounces, making the total weight 
 of the complete power plant 14 ounces. 
 
 THE SCHOBER FOUR CYLINDER OPPOSED 
 MOTOR 
 
 Another interesting type of compressed air 
 motor that has been developed in America is 
 the Schober four cylinder opposed motor. 
 While this motor is different in appearance 
 from most compressed air motors, it has been 
 made to work satisfactorily and is consistent 
 with the same high class construction that is 
 displayed in most all of Mr. Schober's motors. 
 The accompanying diagram 17 illustrates the 
 method of operation of the four cylinder motor. 
 
 The crank case is constructed from four 
 pieces of 24 gauge spring brass, substantially 
 connected in the form of a rectangle, the top 
 and bottom being left open. The front and 
 
COMPRESSED, AIR MOTORS 103 
 
 Diagram 18 
 
104 MODEL AEROPLANES 
 
 rear walls have flanges which engage the inside 
 of the side walls and are secured thereto by 
 four small screws on each side, thereby making 
 it an easy matter to take the crank case apart. 
 
 "The four cylinders are made from drawn 
 brass shells and have a bore of y?' and stroke 
 of y 2 ". The pistons are made of solid 
 red fiber. The two-throw crank-shaft is 
 built up of steel with brass webs. The 
 bearings are of steel. The valves, being over- 
 head, are driven by a gear mounted at the end 
 of the crankshaft, the gear driving the valve 
 shaft by means of a gear on that shaft, with 
 which the crankshaft gear meshes. The valve 
 arrangement, as shown in diagram 18, consists 
 of four recesses cut into the valve shaft, two 
 of which allow the air to pass from the inlet 
 pipes, which lead into the valve chamber at the 
 center of same, to two of the cylinders at once, 
 while the other two recesses allow the exhaust 
 to pass from openings in the sides of the valve 
 chamber. 
 
 The cylinders are secured to the side plates 
 
The interesting horizontal-opposed Jopson gasoline motor 
 for model aeroplanes. The top photograph shows the 
 half-speed shaft and the arrangement of the valve mecha- 
 nism. This engine is air cooled, develops I h.p. at 1,500 
 r.p.m., and weighs 7% Ibs., including gasoline tank and 
 propeller. The bottom view shows the engine with pro- 
 peller in situ. Courtesy Flight. 
 
COMPRESSED AIR MOTORS 105 
 
 of the crank case so that when those side plates 
 are removed, the cylinders are removed with 
 them. The pipes are detachable at their cen- 
 ters; small pipes running to the heads of the 
 cylinders extending into the larger pipes which 
 run to the valve chamber. This arrangement 
 is shown in the end view of the engine. A 17" 
 propeller is used in connection with this engine. 
 
GASOLINE MOTORS 
 
 THE JOPSON I H. P. GASOLINE MOTOR 
 FOR MODEL AEROPLANES 
 
 DURING the past few years several attempts 
 have been made, both in this country and 
 abroad, to produce a reliable gasoline motor for 
 model aeroplane work, but mostly without any 
 degree of success. The reason for this inabil- 
 ity, no doubt, is due to the scarcity of small 
 working parts sufficiently light and at the same 
 time reliable. The engine described herewith, 
 designed by Mr. W. G. Jopson, a member of the 
 Manchester Aero Club, England, is one of the 
 few that have been made to work satisfactorily. 
 
 As the accompanying diagrams 19 and 20 
 and photograph show, the engine is of the four- 
 cycle, horizontal opposed type, having two cast- 
 iron cylinders of ij^" bore and i%" stroke. 
 Each cylinder is cast in one piece, and as the 
 
 106 
 
Wise five cylinder rotary compressed air motor 
 
 Schober-Funk five cylinder rotary motor 
 
 
GASOLINE MOTORS 107 
 
 engine is air cooled, they are cast with radiat- 
 ing fins. One h.p. is developed at 1500 r.p.m. 
 The total weight of the engine, gasoline tank 
 and propeller is *jy 2 Ibs. In preparing the de- 
 sign of this motor, the designs of similar full- 
 sized aero motors were followed as far as pos- 
 sible. The pistons are similar to those used 
 on large aeromotors and are fitted with two 
 rings ; the crankshaft is turned out of two inch 
 special bar steel, and is carried in two phos- 
 phor-bronze bearings. There is no special 
 feature about the connecting rods, these being 
 of the standard type, but very strong and light. 
 To enable the two cylinders to be exactly op- 
 posite one another, the connecting-rods are off- 
 set in the pistons and are connected to the lat- 
 ter by gudgeonpins. The aluminum crank- 
 case is extremely simple, being cylindrical and 
 vertically divided. The inlet valves are auto- 
 matic, the exhaust valves being mechanically 
 operated; the cam-shaft is driven from the 
 main shaft by two-to-one gearing. To assist 
 the exhaust, and also the cooling, small holes 
 
io8 
 
 MODEL AEROPLANES 
 
 Diagram 19 
 
 Sectional elevation of the I h.p. Jopson gasoline motor for 
 models. The disposition of the gasoline tank and wick 
 carburettor is particularly noteworthy. It will be seen 
 that metal journals are provided for the crank-shaft, 
 which is turned out of 2-inch bar steel. Courtesy Flight. 
 
GASOLINE MOTORS 109 
 
 are drilled round the cylinder in such a position 
 that when the piston is at the inner end of its 
 stroke, these holes are uncovered, thus permit- 
 ting the hot exhaust to escape, and so relieve 
 the amount passing through the exhaust valves. 
 The commutator is also driven off the cam- 
 shaft, as shown in the drawing. No distribu- 
 tor is fitted to the commutator, as small ones 
 are somewhat troublesome and very light coils 
 are obtainable at a reasonable price. 
 
 The gasoline tank is made of copper in 
 stream-line form, and is usually fitted to the 
 back of the crankcase, thus reducing the head 
 resistance, but if desired it can be fitted in any 
 other position. The action of the carburettor 
 can be easily seen from the drawings; it is of 
 the surface type and much simpler, lighter and 
 quite as efficient as the spray type. Specially 
 light and simple spark plugs are used, that 
 give very little trouble. The propeller used in 
 connection with this motor is somewhat out of 
 the ordinary, having been specially designed 
 for this engine, and patented. The propeller 
 
no MODEL AEROPLANES 
 
 is made entirely of aluminum and has a varia- 
 ble pitch, this being easily obtainable, as the 
 blades are graduated so that any desired pitch, 
 within certain limits, may be given at once. 
 The results of a series of tests on a 30 inch pro- 
 peller are shown on the accompanying chart, 
 and from it the thrust as certain speeds with a 
 certain pitch can be obtained. Taking the en- 
 gine running at 1540 r.p.m. with a pitch of 15", 
 the thrust comes out at 9^2 Ibs., or more than 
 the weight of the motor and accessories. 
 
GASOLINE MOTORS 
 
 
 X 
 
 AT 1340 tPM, 
 
 X 
 
 X 
 
 9 >Z 15 
 
 PITCH OF BUAOE&CINCHES) 
 
 Diagram 20 
 
 Diagram of results obtained from tests of the I h.p. Jopson 
 model gasoline motor, showing the thrust in pounds at 
 varying speeds with propellers of different pitch. Cour- 
 tesy Flight 
 
THE MIDGET AERO GASOLINE 
 MOTOR 
 
 ALTHOUGH numerous model constructors in 
 America are experimenting with model gaso- 
 line motors, the Midget Gasoline Motor, the 
 product of the Aero Engine Company, Boston, 
 Massachusetts, is perhaps the most satisfac- 
 tory up to the present time. An engine of 
 this type was used by Mr. P. C. McCutchen 
 of Philadelphia, Pennsylvania, in his 8 foot 
 Voisin Type Bi-plane Model, for which he 
 claims a number of satisfactory flights. 
 
 The motor is made from the best iron, steel, 
 aluminum and bronze and the complete weight 
 including a special carburettor, spark plug and 
 spark coil is 2,y 2 Ibs. From the top of the cylin- 
 der head to the bottom of the crank case the 
 motor measures 7". It is possible to obtain 
 from this motor various speeds from 400 to 
 
 112 
 
The Midget ^ H. P. gasoline motor 
 
MIDGET AERO GASOLINE MOTOR 113 
 
 2700 r.p.m., at which speed it develops J4 h.p. 
 The propeller used in connection with this 
 motor measures 18" in diameter and has a 
 13" pitch. 
 
 It might be of interest to know that one of 
 the parties responsible for the development of 
 this motor is Mr. H. W. Aitken, a former 
 model maker and who is now connected with 
 one of the largest aeromotor manufacturing 
 companies in America. 
 
STEAM POWER PLANTS 
 
 ASIDE from the compressed air motor there 
 is the steam driven motor which has been used 
 abroad to a considerable degree of success. 
 Owing to the difficulty in constructing and 
 operating a steam driven motor, very few 
 model flyers in America have devoted any at- 
 tention to the development of this motor as a 
 means of propulsion for model aeroplanes. 
 But irrespective of the limitations of the steam 
 motor a great deal of experimentation has been 
 carried on in England, and without doubt it will 
 soon be experimented with in America. Per- 
 haps one of the most successful steam power 
 plants to have been designed since the develop- 
 ment of the Langley steam driven model, is the 
 Groves type of steam power plant, designed by 
 Mr. H. H. Groves, of England. On one occa- 
 sion several flights were made with a model 
 
 114 
 
STEAM POWER PLANTS 115 
 
 driven by a small steam engine of the Groves 
 type weighing 3 Ibs. The model proved itself 
 capable of rising from the ground under its 
 own power and when launched it flew a distance 
 of 450 feet. This is not a long flight when 
 compared with the flight made by Prof. Lang- 
 ley's steam driven model on November 28, 
 1896, of three-quarters of a mile in I minute 
 and 45 seconds, but the size of the models and 
 also that Mr. Groves' model only made a dura- 
 tion of 30 seconds, must be considered. The 
 model was loaded 12 ounces to the square foot 
 and had a soaring velocity of some 20 m.p.h. 
 The total weight of the power plant was i l /2 
 Ibs. Propeller thrust 10 to 12 ounces. The 
 total weight of the model was 48 ounces. The 
 type of steam plant used in connection with this 
 model was of the flash boiler, pressure fed type, 
 with benzoline for fuel. 
 
 Mr. Groves has done considerable experi- 
 menting with the steam driven type power 
 plant. Many of the designs used in the con- 
 struction of steam plants for models are taken 
 
ii6 MODEL AEROPLANES 
 
 from his designs. A Groves steam power 
 plant is employed in one of Mr. V. E. Johnson's 
 (Model Editor of Flight) model hydroaero- 
 planes, the first power-driven, or "mechanically 
 driven" model hydroaeroplane (so far as can 
 be learned) to rise from the surface of the 
 water under its own power. This model has a 
 total weight of 3 Ibs. 4 ounces. 
 
 Another advocate of the steam driven type 
 model is Mr. G. Harris, also of England. Sev- 
 eral good flights were made by Mr. Harris 
 with his pusher type monoplane equipped with 
 a steam driven motor. As a result of his ex- 
 periments he concluded that mushroom valves 
 with a lift of 1-64 part of an inch were best, 
 used in connection with the pump, and at least 
 12 feet of steel tubing should be used for boiler 
 coils. The first power plant constructed by 
 Mr. Harris contained a boiler coil 8 feet long, 
 but after he had replaced this coil with one 12 
 feet long, irrespective of the fact that the extra 
 length of tube weighed a couple of ounces, the 
 thrust was increased by nearly a half pound. 
 
An English steam power plant for model aeroplanes. 
 Courtesy Flight. 
 
 Model hydroaeroplane owned by V. E. Johnson, Model Edi- 
 tor of Flight, England, equipped with an H. H. Groves 
 steam power plant. This model is the first power driven 
 as far as can be learned to rise from the surface of the 
 
 water under its own power. Courtesy Flight. 
 
STEAM POWER PLANTS 117 
 
 The principal parts used in Mr. Harris's steam 
 power plant was an engine of the H. H. Groves 
 type, twin cylinder, %" bore with a piston 
 stroke of y 2 ". The boiler was made from 12" 
 of 3-16" x 20" G. steel tubing, weighing 10.5 
 ounces. The blow lamp consisted of a steel 
 tube, 5-32" x 22" G. wound round a carbide 
 carrier for a nozzle. The tank was made 
 of brass 5-1000" thick. The pump, 7-32" bore, 
 stroke variable to J4", fitted with two non-re- 
 turn valves (mushroom type) and was geared 
 down from the engine 4.5 to I. 
 
 The Langley steam driven model, of which 
 so much has been said, and which on one occa- 
 sion flew a distance of one-half mile in 90 sec- 
 onds, had a total weight of 30 Ibs., the motor 
 and generating plant constituting one-quarter 
 of this weight. The weight of the complete 
 plant worked out to 7 Ibs. per h.p. The engine 
 developed from i to 1^2 h.p. A flash type 
 boiler was used, with a steam pressure of from 
 150 to 200 Ibs., the coils having been made of 
 copper. A modified naphtha blow-torch, such 
 
ii8 MODEL AEROPLANES 
 
 as is used by plumbers, was used to eject a blast 
 or flame about 2000 Fahrenheit through the 
 center of this coil. A pump was used for cir- 
 culation purposes. With the best mechanical 
 assistance that could be obtained at that date, 
 it took Professor Langley one year to construct 
 the model. 
 
 About ten months after Langley's results, 
 some experiments were carried out by the 
 French at Carquenez, near Toulon. The 
 model used for the experiments weighed in 
 total 70 Ibs., the engine developing more than 
 I h.p. As in the Langley case, twin propellers 
 were used, but instead of being mounted side by 
 side, they were mounted one in front and the 
 other behind. The result of these experiments 
 compared very poorly with Langley's. A 
 flight of only 462 feet was made, with a dura- 
 tion of a few seconds. The maximum velocity 
 is stated to have been 40 m.p.h. The span of 
 this model was a little more than 6 meters, or 
 about 19 feet, with a surface of more than 8 
 square meters, or about 80 square feet. 
 
An English hydroaeroplane of tractor design equipped with 
 steam power plant. Courtesy Flight. 
 
 On the right an English 10 oz. Compressed air driven bi- 
 plane On the left, the engine shown fitted with a simple 
 speedometer for experimental purposes. Courtesy Flight. 
 
WORLD'S MODEL FLYING RECORDS 
 (TwiN PROPELLER PUSHER TYPE MODELS) 
 
 MONOPLANE 
 
 Year 1916. Thomas Hall (America), hand launched, 
 distance 5337 feet. 
 
 Year 1915. Wallace A. Lauder (America), hand 
 launched, distance 3537 feet. 
 
 Year 1915. Wallace A. Lauder (America), hand 
 launched, duration 195 seconds. 
 
 Year 1914. Fred Watkins (America), rise off ground, 
 distance 1761 feet. 
 
 Year 1914. J. E. Louch (England), rise off ground, 
 duration 169 seconds. 
 
 Year 1915: E. C. Cook (America), rise off water, dur- 
 ation 100 seconds. 
 
 (TwiN PROPELLER TRACTOR TYPE) 
 
 MONOPLANE 
 
 Year 1913. Harry Herzog (America), rise off water, 
 duration 28 seconds. 
 
 (TwiN PROPELLER PUSHER TYPE) 
 BIPLANE 
 
 Year 1915. A. H. Wheeler (America), rise off 
 ground, duration 143 seconds. 
 119 
 
120 MODEL AEROPLANES 
 
 (SINGLE PROPELLER PUSHER TYPE) 
 
 MONOPLANE 
 
 Year 1914. J. E. Louch (England), hand launched, 
 
 duration 95 seconds. 
 Year 1914. W. E. Evans (England), rise from ground, 
 
 distance 870 feet. 
 Year 1914. J. E. Louch (England), rise from ground, 
 
 duration 68 seconds. 
 Year 1914. L. H. Slatter (England), rise from water, 
 
 duration 35 seconds. 
 
 (SINGLE PROPELLER TRACTOR TYPE) 
 MONOPLANE 
 
 Year 1915. D. Lathrop (America), hand launched, 
 
 distance 1039 feet. 
 Year 1915. D. Lathrop (America), hand launched, 
 
 duration 240 seconds. 
 Year 1914. C D. Button (England), rise from 
 
 ground, distance 570 feet. 
 Year 1914. J. E. Louch (England), rise from ground, 
 
 duration 94 seconds. 
 Year 1915. L. Kittle (America), rise from water, 
 
 duration 116 seconds. 
 
 (SINGLE PROPELLER TRACTOR TYPE) 
 
 BIPLANE 
 
 Year 1915. Laird Hall (America), rise from ground, 
 duration 76 seconds. 
 
FLYING RECORDS 121 
 
 (FLYING BOAT TYPE) 
 MONOPLANE 
 
 Year 1915. Robert La Tour (America), rise from 
 water, duration 43 seconds. 
 
 (FLYING BOAT TYPE) 
 
 BIPLANE 
 
 Year 1914. C. V. Obst (America), rise from water, 
 duration 27 seconds. 
 
 (MECHANICAL DRIVEN MODEL) 
 
 Year 1914. D. Stanger (England), rise from ground, 
 duration 51 seconds. 
 (All British records are quoted from Flight) 
 
DICTIONARY OF AERONAUTICAL 
 TERMS 
 
 AERODROME A tract of land selected for flying pur- 
 poses. 
 
 AERODYNAMICS The science of Aviation, literally the 
 study of the influence of air in motion. 
 
 AEROFOIL A flat or flexed plane which lends support 
 to an aeroplane. 
 
 AERONAUT One engaged in navigating the air. 
 
 AERONAUTICS The science of navigating the air. 
 
 AEROPLANE A heavier than air machine supported by 
 one or more fixed wings or planes. 
 
 AEROSTATICS The science of aerostation, or of buoy- 
 ancy caused by displacement, ballooning. 
 
 AEROSTATION The science of lighter than air or gas- 
 born machines. 
 
 AILERON The outer edge or tip of a wing, usually 
 adjustable, used to balance or stabilize. 
 
 AIRSHIP Commonly used to denote both heavier and 
 lighter than air machines; correctly a dirigible 
 balloon. 
 
 ANGLE OF INCIDENCE The angle of the wing with 
 the line of travel. 
 
 122 
 
DICTIONARY OF TERMS 123 
 
 ARES In the case of wings, the extent of surface 
 measured on both the upper and lower sides. An 
 area of one square foot comprises the actual sur- 
 face of two square feet. 
 
 ASPECT RATIO The proportion of the chord to the 
 span of a wing. For example if the wing has a 
 span of 30 inches and a chord of 6 inches the 
 
 span 
 
 aspect ratio will be 5 or . , 
 
 Chord. 
 
 AUTOMATIC STABILITY Stability secured by fins, the 
 angle of tne wings and similar devices. 
 
 AVIATOR One engaged in Aviation. 
 
 AVIATION The science of heavier than air machines. 
 
 ANGLE OF BLADE The angle of the blade of a propeller 
 to the axis of the shaft. 
 
 B 
 
 BALANCER A plane or other part intended for lateral 
 
 equilibrium. 
 
 BEARING BLOCK Used in connection with the mount- 
 ing of propellers on model aeroplanes. Made 
 
 from wood and metal. 
 BRACE Strip of bamboo or other material used to join 
 
 together the frame side members. Also used in 
 
 joining other parts of a model. 
 BIPLANE An aeroplane or model aeroplane with two 
 
 wings superposed. 
 BODY The main framework supporting the wing or 
 
 wings and the machinery. 
 
i2 4 MODEL AEROPLANES 
 
 BANKING The lateral tilting of an aeroplane when 
 taking a turn. 
 
 C 
 
 CAMBER The rise of the curved contour of an arched 
 surface above the Chord Line. 
 
 CENTER OF GRAVITY The point at which the aero- 
 plane balances. 
 
 CENTER OF PRESSURE The imaginary line beneath the 
 wing at which the pressure balances. 
 
 CHASSIS (CARRIAGE) The part on which the main 
 body of an aeroplane or model aeroplane is sup- 
 ported on land or water. 
 
 CHORD The distance between the entering and trail- 
 ing edges of a wing. 
 
 D 
 
 DECK The main surface of a biplane or multiplane. 
 DIRECTIONAL CONTROL The ability to determine the 
 
 direction of the flight of an aeroplane. 
 DIRIGIBLE A balloon driven by power. 
 DOPE A coating for wings. 
 DOWN WING With the wind. 
 DRIFT The resistance of the wing to the forward 
 
 movement. 
 DIHEDRAL ANGLE The inclination of the wings to each 
 
 other usually bent up from the center in the form 
 
 of a flat V. 
 
 E 
 
 ELEVATOR The plane or wing intended to control the 
 vertical flight of the machine. 
 
DICTIONARY OF TERMS 125 
 
 ENGINEER One who controls the power, driving the 
 
 machinery. 
 ENTERING EDGE or LEADING EDGE Front edge or edge 
 
 of the surface upon which the air impinges. 
 EQUILIBRATOR A plane or other contrivance which 
 
 makes for stability. 
 
 FIN A fixed vertical plane. 
 
 FLEXED A wing is said to be flexed when it curves up- 
 ward forming an arc of a circle. 
 
 FLYING STICK Name applied to ordinary A type and 
 single stick models. 
 
 FLYING MACHINE Literally a form of lighter than 
 air craft ; a gas-borne airship. 
 
 FLYING BOAT A hull or large float used in connection 
 with an aeroplane to enable its rising from and 
 alighting upon the surface of the water. 
 
 FRAME A single or double stick structure to which all 
 parts of a model are attached. Three or more 
 sticks are sometimes employed in the construction 
 of a frame. However, the usual number is two, 
 joined together in the form of letter "A." 
 
 FRAME HOOKS The looped ends of a piece of wire at- 
 tached to the point of the frame to accommodate 
 the S hooks attached to the rubber strands. 
 
 FRAME SIDE MEMBERS Two main sticks of an A type 
 frame. 
 
 FUSELAGE The body or framework of an aeroplane. 
 
126 MODEL AEROPLANES 
 
 GLIDER An aeroplane without motive power. 
 
 GUY A brace, usually a wire or cord used for tuning 
 up the aeroplane. 
 
 GROSS WEIGHT The weight of the aircraft, compris- 
 ing fuel, lubricating oils and the pilot. 
 
 GYROSCOPE A rotating mechanism for maintaining 
 equilibrium. 
 
 GAP The vertical distance between the superposed 
 wings. 
 
 H 
 
 HANGAR A shed for housing an aeroplane. 
 
 HARBOR A shelter for aircraft. 
 
 HEAVIER THAN AIR A machine weighing more than 
 the air it displaces. 
 
 HELLI COPTER A flying machine in which propellers are 
 utilized to give a lifting effect by their own direct 
 action on the air. In aviation the term implies 
 that the screw exerts a direct lift. 
 
 HELMSMAN One in charge of the steering device. 
 
 HYDROAEROPLANE An aeroplane with pontoons to en- 
 able its rising from the surface of the water. 
 Known as hydro in model circles. 
 
 K 
 
 KEEL A vertical plane or planes arranged longitudi- 
 nally either above or below the body for the pur- 
 pose of giving stability. 
 
DICTIONARY OF TERMS 127 
 
 L 
 
 LATERAL STABILITY Stability which prevents side mo- 
 tion. 
 
 LOADING The gross weight divided by the supporting 
 area measured in square feet. 
 
 LONGITUDINAL STABILITY Stability which prevents 
 fore and aft motion or pitching. 
 
 LONGERONS Main members of the fuselage. Some- 
 times called longitudinals. 
 
 M 
 
 MAST A perpendicular stick holding the stays or 
 struts which keep the wings rigid. 
 
 MODEL AEROPLANE A scale reproduction of a man- 
 carrying machine. 
 
 MECHANICAL POWER A model driven by means other 
 than rubber strands such as compressed air, steam, 
 gasoline, spring, electricity and so forth is termed 
 a mechanical driven model. The power used is 
 termed mechanical power. 
 
 MOTIVE POWER In connection with model aeroplanes a 
 number of rubber strands evenly strung from the 
 propeller shaft to the frame hooks which while 
 unwinding furnish the necessary power to propel 
 the model. 
 
 MAIN BEAM In connection with model aeroplanes 
 a long stick which is secured to the under side of 
 the wing frame at the highest point in the curve 
 of the ribs adding materially to the rigidity of the 
 wing. 
 
128 MODEL AEROPLANES 
 
 MONOPLANE An aeroplane or heavier than air ma- 
 chine supported by a single main wing which may 
 be formed of two wings extending from a central 
 body. 
 
 MOTOR A contrivance for generating driving power. 
 
 MULTIPLANE An aeroplane with more than four 
 wings superposed. 
 
 MOTOR BASE Main stick used for frame of single stick 
 model. 
 
 N 
 
 NACELLE The car of a dirigible balloon, literally a 
 cradle. Also applied to short body used in connec- 
 tion with aeroplanes for the accommodation of the 
 pilot and motor. 
 
 NET WEIGHT Complete weight of the machine with- 
 out pilot, fuel or oil. 
 
 ORNITHOPTER A flapping wing machine which has 
 arched wings like those of a bird. 
 
 ORTHOGONAL A flight maintained by flapping wings. 
 
 OUTRIGGERS Members which extend forward or rear- 
 ward from the main planes for the purpose of 
 supporting the elevator or tail planes of an aero- 
 plane. 
 
 P 
 
 PLANE A surface or wing, either plain or flexed, em- 
 ployed to support or control an aeroplane. 
 PILOT One directing an aeroplane in flight. 
 
DICTIONARY OF TERMS 129 
 
 PITCH Theoretical distance covered by a propeller in 
 
 making one revolution. 
 
 PROPELLER The screw used for driving an aeroplane. 
 PROPELLER BEARINGS Pieces of bronze tubing or strips 
 
 of metal formed to the shape of the letter "L" 
 
 used to mount propellers. Also made from blocks 
 
 of wood. 
 PROPELLER BLANK A block of wood cut to the design 
 
 of a propeller. 
 PROPELLER SPAR(S) The heavy stick or sticks upon 
 
 which the bearing or bearings of a single or twin 
 
 propeller model are mounted. 
 PROPELLER SHAFT A piece of wire which is run 
 
 through the hub of the propeller and tubing in 
 
 mounting the propeller. 
 PYLON Correctly, a structure housing a falling weight 
 
 used for starting an aeroplane, commonly a turn- 
 ing point in aeroplane flights. 
 PUSHER An aeroplane with the propeller or propellers 
 
 situated in back of the main supporting surfaces. 
 
 QUADRUPLANE An aeroplane with four wings super- 
 posed. 
 
 RUDDER A plane or group of planes used to steer an 
 
 aeroplane. 
 RUNNER Strip beneath an aeroplane used for a skid. 
 
130 MODEL AEROPLANES 
 
 RUNNING GEAR or LANDING GEAR That portion of 
 the chassis consisting of the axle, wheels and shock 
 absorber. 
 
 RIB Curved brace fastened to the entering and trail- 
 ing edges of a wing. 
 
 SCALE MODEL A miniature aeroplane exactly repro- 
 ducing the proportions of an original. 
 
 SPAR A mast strut or brace. 
 
 SIDE SLIP The tendency of an aeroplane to slide or 
 slip sideways when too steep banking is attempted. 
 
 STABILITY The power to maintain an even keel in 
 flight. 
 
 STARTING PLATFORM A runway to enable an aero- 
 plane to leave the ground. 
 
 SURFACE FRICTION Resistance offered by planes or 
 wings. 
 
 SLIP The difference between the distance actually 
 traveled by a propeller and that measured by the 
 pitch. 
 
 SOARING FLIGHT A gliding movement without ap- 
 parent effort. 
 
 SUSTAINING SURFACE Extent of the wings or planes 
 which lend support to an aeroplane. 
 
 SPAN (SPREAD) The dimension of a surface across 
 the air stream. 
 
 STREAMLINE Exposing as little surface as possible to 
 offer resistance to air. 
 
DICTIONARY OF TERMS 131 
 
 SKIDS In connection with model aeroplanes, steel 
 wires or strips of bamboo allowed to extend below 
 the frame to protect the model in landing and to 
 permit its rising off the ground or ice. 
 
 S OR MOTOR HOOKS A piece of wire bent in a double 
 hook to resemble the letter "S." One end to 
 be attached to the frame hook, the other serving 
 as accommodation for the rubber strands. 
 
 TAIL The plane or planes, both horizontal and verti- 
 cal, carried behind the main planes. 
 
 TANDEM An arrangement of two planes one behind 
 the other. 
 
 THRUST The power exerted by the propeller of an 
 aeroplane. 
 
 TENSION The power exerted by twisted strands of 
 rubber in unwinding. 
 
 TRACTOR An aeroplane with the propeller situated be- 
 fore the main supporting surfaces. 
 
 TRIPLANE An aeroplane with three wings superposed. 
 
 TRAILING EDGE The rear edge of a surface. 
 
 TORQUE The twisting force of a propeller tending to 
 overturn or swerve an aeroplane sideways. 
 
 U 
 UP WIND Against the wind. 
 
 W 
 
 WAKE The churned or disturbed air in the track of a 
 moving aeroplane. 
 
132 MODEL AEROPLANES 
 
 WASH The movement of the air radiating from the 
 sides of an aeroplane in flight. 
 
 WINGS Planes or supporting surfaces, commonly a 
 pair of wings extending out from a central body. 
 
 WINDER An apparatus used for winding two sets of 
 rubber strands at the same time in opposite direc- 
 tions or one at a time. Very often made from an 
 egg beater or hand drill. 
 
 WARPING The springing of a wing out of its normal 
 shape, thereby creating a temporary difference in 
 the extremities of the wing which enables the wind 
 to heel the machine back again into balance. 
 
 ABREVIATIONS 
 
 H. P. Horse Power. 
 
 R. P. M. Revolutions per minute. 
 
 H. L. Hand launched. 
 
 R. O. G. Rise off ground model. 
 
 R. O. W. Rise off water model. 
 
 M. P. H. Miles per hour. 
 
 THE END 
 
14 DAY USE 
 
 RETURN TO DESK FROM WHICH BORROWED 
 
 LOAN DEPT. 
 
 This book is due on the last date stamped below, 
 or on the date to which renewed. Renewals only: 
 
 Tel. No. 642-3405 
 
 Renewals may be made 4 days prior to date due. 
 Renewed books are subject to immediate recall. 
 
 29 197361 
 
 General Library 
 Univershy^ California