AIRSHIP MANUAL r v. D'ORCY'S AIRSHIP MANUAL D'ORCY'S AIRSHIP MANUAL AN INTERNATIONAL REGISTER OF AIRSHIPS WITH A COMPENDIUM OF THE AIRSHIP'S ELEMENTARY MECHANICS COMPILED AND EDITED BY LADISLAS D'ORCY, M.S.A.E. PUBLISHED BY THE CENTURY CO. NEW YORK : MCMXVII COPYRIGHT, 1917, BY THE CENTURY Co. Published October, 1917 THE ILLUSTRATIONS ARE FROM SPECIAL DRAWINGS BY GEO. F. MCLAUGHLIN. THE PHOTOGRAPHS ARE KINDLY LENT BY MR. HENRY WOODHOUSE FROM HIS PRIVATE COLLECTION. 7 A la Me'moire des Ae'rostiers de la Republique et de ses Allies marts pour la Liberte des Peuples. To the Memory of the Aeronauts of the French Republic and of her Allies who died for the Freedom of the Peoples. 369966 CONTENTS INTRODUCTION ELEMENTARY MECHANICS OF THE AIRSHIP THE AIRSHIP IN THE GREAT WAR I THE WORLD AIRSHIP BUILDERS . . . II THE WORLD'S AIRSHIP PRODUCTION . . III THE MILITARY AIRSHIP FLEETS . . . IV COMPARATIVE STRENGTH OF THE MILITARY PAGE I V AIRSHIP LOSSES OF THE ALLIES VI GERMANY'S AIRSHIP LOSSES PAGE 199 2OI VII THE GERMAN AIRSHIP RAIDS ON GREAT BRITAIN 205 AIRSHIP FLEETS 2 39 5 1 l8 S VIII THE COMMERCIAL AIRSHIP FLEETS OF 1914 209 IX THE WORLD'S AIRSHIP SHEDS .... 313 197 INDEX 229 NOTICE In compliance with the recommendations of the National Advisory Committee for Aeronautics, all data in D'Orcy's Airship Manual are expressed in the metric system. For the convenience of readers unfamiliar with the metric system the approximate equivalents of the metric units employed are herewith given in English units: I meter (m.) = 3% feet. i kilometer (km.) = f statute mile. I cubic meter (cbm. or me.) = 353- cubic feet. ' I kilogram (kg.) = 2^ pounds. I metric ton = 2,200 pounds. INTRODUCTION The present volume is the result of a methodical investigation extending over a period of four years in the course of which many hundreds of English, French, Italian, German and Spanish publications and periodicals dealing with the present status as well as with the early history of airships have care- fully been consulted and digested. It has thus become possible to gather under the cover of a handy reference-book a large amount of hitherto widely scattered information which, having mostly been published in, foreign languages, was not im- mediately available to the English speaking public. The information thus gathered is herewith pre- sented in two parts; one being a compendium of the elementary principles underlying the construc- tion and operation of airships, the other constitut- ing an exhaustive, but tersely worded register of the world's airshipping which furnishes, whenever available, complete data for every airship of 500 cubic meters and over, that has been laid down since 1834. Smaller airships are listed only if they embody unusual features. It has been attempted to furnish here the most up-to-date information regarding the gigantic fleet of airships built by Germany since the beginning of the Great War, a feature which may, in a certain measure, repay the reader for the utter lack of data on the Allies' recent airship constructions, which had to be withheld for military reasons. A revised and enlarged edition of D'Orcy's Airship Manual, in which all the airships built during the Great War will be listed and their features duly discussed, will be issued upon the termination of the war. Ladislas d'Orcy, New York City (U. S. A.) ELEMENTARY MECHANICS OF THE AIRSHIP Definition and Classification. The airship be- longs, with its immediate forerunner, the free bal- loon, to the family of static aircraft. Static aircraft derive their sustentation from a hull which is filled with a gas lighter than air ; free balloons and airships consequently float in the atmosphere, like ships float on the sea, by virtue of buoyancy. The airship's sustentation is, unlike that of the aeroplane, independent of forward motion, in other words, the airship can stay aloft without expending engine power, in which case it drifts with the pre- vailing wind like a free balloon. The airship is the outcome of a century-long endeavor to endow the free balloon with inde- pendent velocity whereby it would be able to navigate the atmosphere regardless of winds in any direction desired; hence the now little used terms of "navigable" and "dirigible balloon" under which the airship first became known. The very nature of the airship's sustentation, which permits to assimilate the airship to the ship of the sea, sufficiently justifies the retention of the term "airship" and the condemnation of the term "dirigible," the customary abbreviation of "dirigible balloon," which may reasonably be applied to the aeroplane too, since it fails to specify the type of aircraft it is supposed to describe. The hitherto customary division of airships into the rigid, semi-rigid, and non-rigid types, which was based on primitive and now obsolescent con- ceptions, has been found totally inadequate to ex- press the features of novel sub-types which have more recently been produced; it has therefore been deemed advisable to adopt a new nomenclature, based on the constructional features of the hull which alone permit fundamental differentiation. Whereas every airship hull presents to the rela- tive wind an essentially rigid body, it follows that the term " rigid " cannot logically be applied to one particular airship type, the same argument* "barring also the terms " semi-rigid " and " non- rigid." Consequently all airships in which the shape of the hull is rendered permanent by means of a rigid structure, the hull frame, are here termed structure airships, whereas all those in which the shape of the hull is maintained through internal pressure are here listed as pressure airships. Structure Airships. The fundamental principles of the structure airship were first laid down in a. patent taken out in 1873 D Y the Alsatian engineer Joseph Spiess. Twenty years later David Schwarz of Zagreb (Croatia) built at Petrograd a structure airship which was the earliest representative of its kind, but it was a failure. Shortly afterwards Count Ferdinand von Zeppelin, a German cavalry general, emulated Schwarz, whose patents he had purchased, and eventually succeeded in developing by gradual improvement of design the highly effi- cient modern structure airship. Structure airships are characterized by a rigid hull frame generally built up of longitudinal girders which are connected at intervals by polygonal ties; the resulting frame- work is covered with a waterproof, but non-gas- tight, fabric skin. On Zeppelin airships every sec- ond tie is braced athwartships by a radial wire truss resembling the spokes of a bicycle wheel, through the hub of which a steel hawser runs from stem to stern. Both the hawser and the radial truss wires are fitted with turnbuckles whereby the whole frame- work may be tightened up when required. The radial, or tie, trusses form the compartments in which from 1 8 to 24 individual gas-cells are housed; the cells are drum-shaped and are fitted with an inflation appendix and a relief-valve. Owing to the constancy of displacement realized by the hull frame, no deformation will occur through a con- traction of the hydrogen, whereas an expansion of the gas will be promptly relieved by the auto- matic and manually operated valves; but as the latter process may create an explosive mixture between the gas-cells and the outer cover, it is necessary to keep this space constantly ventilated by forced draught, the escaping hydrogen being expelled through shafts leading to the roof. These shafts are fitted with automatic valves which can also be manually controlled. As a further measure of precaution recent Zeppe- lin airships have the lower half of the outer skin treated with a gas-proof varnish to prevent its pene- tration by the heavy and impure gas collecting in the bottom of the gas-cells, which on coming in contact with the engine exhaust might set the vessel on fire. The portions of the hull which are in the immedi- ate neighborhood of the propellers are protected against possible injury from this source by a plating of veneer. It has been reported that on the latest Zeppelin airships the gas-cells are connected with a storage tank whither the expanding hydrogen escapes under rising pressure through automatic valves and whence it can be pumped back into the gas- cells when the hydrogen contracts. Whatever truth there be in this so far unverified statement, it is obvious that such a storage tank would greatly obviate the structure airships' great drawback of losing gas and consequently lift in the process of regulating variations of gas-pressure. A similar arrangement incidentally existed on the first Schutte-Lanz airship, where the excess of gas gen- erated by rising pressure was forced by means of a centrifugal pump into two gas-cells which remained empty at sea-level pressure. This system enabled the airship to reach an altitude of 2,000 meters without any loss of gas. The Hull Frame. The material employed in the construction of hull frames is either a zinc aluminum alloy or wood. The former is used in Zeppelin air- ships in the shape of triangular lattice girders, whereas in the Schtitte-Lanz airships laminated wood girders are employed. The wooden girders of the Spiess airship were of tubular form, built in halves and glued together. The longitudinals and polygonals of Zeppelin air- ships are built up of punch-pressed corner-rails and X-pieces; they are riveted together so as to form triangular girders. The only authoritative state- ment regarding the strength and weight of these girders is one by Count Zeppelin to the effect that on his first airship " the aluminum which served as the material of construction had a specific weight of 2.7 kg. and a tensile strength of 33 kg. per square meter of surface. The frames proper (longitudinals) were built of angle and T-bars and the bracing girders (polygonals) of angle bars. The weight of these frames, as applied to the construc- tion, was '0.9 and 1.8 kg. per meter length, this being equivalent to 0.516 kg. per cubic meter of volume." On the Zeppelin airship Sachsen, built in 1913, the adoption of an aluminum alloy of greater tensile strength and the use of triangular girders resulted in a considerable increase in strength, while the weight per meter of length was reduced by 0.13 kg. . On the first Schutte-Lanz airship the hull frame consisted of a closely meshed lattice-work of lami- nated wood girders, spirally wound and diagonally DIAGRAM OF AN 18,000 CBM. ZEPPELIN AIRSHIP, THE SCHWABEN (STRUCTURE TYPE). 1-17 gas cells; a^a, propeller stays; b transmission shaft; di forward car; d 2 after car; d, cabin car; h,, h 2 elevators; ki, k 2 , k 3 radiators 1 gangway; m propeller outrigger; ni-n< propellers; Oi-o 3 horizontal planes; 02 vertical plane; p rudder. crossed, which were kept under tension by cir- cular ties and an elaborate steel wire trussing. This framework possessed a certain amount of springiness which constituted a valuable asset in the case of a rough landing; unfortunately the time and cost of production of this hull proved to be so great that it had to be abandoned on later ships for the Zeppelin type of construction, though the material remained the same. Hull Shapes. One of the most important items of hull design is that of the shape, for this deter- mines the amount of air resistance that must be overcome, the most favorable shape being obvi- ously the one which affords the greatest power economy and develops the least stresses while the airship is under way. The first requirement is primarily one of general efficiency, since the saving of one horse-power reduces, on the average, the dead and live loads (weight of engine, fuel, oil, and cooling water) by 3 kg. per hour of operation. The saving thus effected may advantageously be turned into an increase of fuel, ballast, etc., and is therefore of considerable interest to the airship- builder. The stresses developed by an airship hull in its progress through the air are of two kinds : compres- sion on the bow through impact resistance, and tension on the sides and on the stern through fric- tional resistance and suction, respectively. On structure airships these stresses are, on account of the rigid hull frame, only of relative importance, namely, in so far as they are accompanied by para- site resistance which decreases the power efficiency and by a certain wear of the outer cover. Their value is, nevertheless, considerable enough, for the impact resistance of an airship travelling at a speed of 90 kilometers per hour represents a pressure of 75 kg. per square meter of projected area, that is the area of the cross-section at the master-diameter. On pressure airships, where the hull retains its shape exclusively through internal pressure, the question of using a hull of "streamline" shape that is, of easy penetration is, on the contrary, one of primary importance. According to M. Eiffel, the air resistance which a pressure airship develops in her progress through the air causes a deformation in the hull whereby its volume may increase by as much as 10 per cent, of its displacement. Since to the strain caused by this deformation, which tends to weaken the envelope, must be added those cre- ated by the excess of internal pressure as well as by the considerable bending moment existing in all pressure airships (except .in those of the tension truss type), it follows that the design of pressure DIAGRAM OF A 19,000 CBM. SCHUTTE-LANZ AIRSHIP, THE 5. L. I. (STRUCTURE TYPE), forward car; G 2 after car; Pj, Pj propellers; HI forward elevator; Hj after elevator; Sti, St 3 stabilizer planes; Si, 82 rudders. Courtesy of The Aeroplane. SPECIMEN OF A ZEPPELIN LATTICE-GIRDER. 7 airship hulls should closely follow the best results arrived at through laboratory research work. Aerodynamic Notes on Hulls. A certain diverg- ence of views exists regarding the best streamline shape for airship hulls. In principle the most effi- cient shape appears to be one elliptical, six diam- eters long, with the master-diameter at about from 30 to 40 per cent, of the length aft of the nose, the bow being somewhat blunter than the stern. This shape is the one proposed by the British and French laboratories; the German laboratory sug- gests a similar shape except for the stern, which should taper off to a sharp point. The principle of the dissymmetrical shape of hull was first laid down by the Frenchman Jullien, who built in 1850 an airship model of such shape; it was later taken up and further developed by Captain Renard of the French Army Engineers, who built the celebrated airship La France. Nowadays this shape is used on all but the Zeppelin airships, where the prevalent reason for building the hull straight-sided for three- quarters of its length seems to be facility of con- struction. Standardization of parts used in the construction of the hull frame thus becomes per- fectly feasible for Zeppelin airships, a feature well nigh impossible to achieve were all the longitudinals of different curvature and all polygonals of different diameter, as would be the case in a true streamline shape of hull. Besides reducing the air resistance to be over- come the dissymmetrical, fish-shaped hull has the property of endowing the airship with a certain amount of "weathercock stability" which means that the vessel will tend to always turn into the wind, unless otherwise directed. This feature is very important, because a solid of revolution which progresses in the direction of its longitudinal axis is in a state of indifferent equilibrium, that is to say, the slightest inclination of the axis suffices to produce a turning couple which may cause the air- ship to assume a vertical position relative to the ground. Nevertheless, the fish-shaped hull, even when combined with fin surfaces abaft, can check longi- tudinal instability only up to a certain speed, called the critical speed, which varies according to the radius of curvature of the hull and the angle of inclination to the horizontal. Pressure Airships. The principal feature which distinguishes pressure airships from structure air- ships is that in the former the hull retains its shape through the agency of internal pressure, which must exceed the atmospheric pressure, and not by means of a hull frame. 8 The theory of the pressure airship was first enunciated in a memorandum which General Meusnier submitted in 1784 to the French Academy of Sciences and in which he incorporated a very comprehensive design of a pressure airship. "The Meusnier design was indeed a creation of fundamen- tal importance which, for want of engine power, had to wait upwards of a century before it could be practically employed. " (Zahm.) The first pressure airship that navigated under limited control the air was built in 1852 by Henri Giffard, the inventor of the steam-injector. This steam propelled airship was followed in 1884 by Captain Renard's electrically driven La France which was the first airship to make a return voyage against a moderate wind. The advent of the in- ternal combustion engine completed the pressure airship's conquest of the aerial ocean in 1902 when Henri Juillot produced the gasoline driven "Lebaudy. The Ballonnet. Excess of pressure is generated on most pressure airships by means of one or more ba'onnets, or bladders, which are located in the bot- tom of the hull and can be inflated with air through a fan-blower. A contraction of the gas and the resulting loss of volume and deformation of the hull are thus compensated for by an expansion of the ballonnet ; on the contrary, an expansion of the gas beyond a certain limit (generally 30 mm. of water) will open the ballonnet valves and relieve the pres- sure without loss of gas, through the only escape of air. Should, however, the pressure still rise in spite of the open ballonnet valves the pressure with- in the hull will be relieved by the automatic gas valves which are generally timed to open at 35-40 mm. of water. Both gas and air valves are of the spring-loaded type. Some airships are provided with gas valves both on the top and on the bottom of the hull in which case the upper ones act as safety valves while the lower ones serve as manoeuvre valves. This system permits to expel the heavy, impure gas col- lecting in the bottom of the hull, thus saving the pure gas for further service. Since the very existence of a pressure airship is dependent upon ability to maintain the shape of the hull regardless of variations of atmospheric pressure and temperature, it follows that both the ballonnet and the relief -valves must have a sufficient capacity effectively to compensate sudden changes of buoyancy. For this reason it is also customary to employ on modern airships an auxiliary engine for actuating the ballonnet-blower, thus making the latter independent of a possible breakdown of the main power plant. The ballonnet was invented in 1872 by the French naval architect Dupuy de Lome, although its in- vention is generally accredited to General Meusnier. The latter proposed on the contrary to maintain the tautness of the hull by means of a double skin, the internal acting as a gas-container while the external skin would be -nothing but a protective cover. The continuous air space between the two skins would not only allow its being inflated at the excess of pressure required, but would also give the gas-container an efficient insulation against varia- tions of temperature. This over-a-century-old idea has lately been em- bodied with marked success in the Forlanini type of airships. There the gas container is suitably trussed to the outer cover so that both will maintain their correct relative position. Excess of pressure within the air space is generated in two ways. When the airship is under way an intake valve fitted to the nose of the hull admits and distributes the on- rushing air to the air space whence it escapes through a relief valve mounted on the stern, the amount of internal pressure being regulated by the greater or lesser aperture of the relief valve. Thanks to this arrangement the air circulates all the time around the gas-container and effectively prevents the leaking hydrogen from creating an explosive mixture. When the engines are stopped excess of pressure is generated in the usual way, that is, by means of a fan-blower. Rubberized Fabric. The considerable stresses to which the hull of pressure airships is subjected have brought about the adoption of rubberized fabric of high tensile strength. On Parseval airships of over 8,000 cubic meter volume the fabric is tested to withstand a pressure of 2 metric tons per square meter of surface. For this purpose diagonal doubling is resorted to, which consists in building up the fabric of two or three layers, the threads of which diagonally oppose each other. To counteract the destructive influence of sun- light on rubberized fabric the latter is generally treated on the outside with chrome yellow or aluminum paint. Hence the yellow or silvery color of most airship hulls. Airships whose outer cover is made of rubberized fabric are subject to danger of fire from self -electri- fication because this material quickly becomes elec- trified in dry air. "When rolled up or creased in any way it rustles and gives out electric sparks, the latter being clearly visible in the dark." (Moedebeck.) This danger is particularly characteristic of pres- sure airships where insufficient tautness of the rub- berized envelope and gas leakage may combine to ii \ cause disastrous results. On structure airships this danger is greatly lessened by the use of non- rubberized fabric in the outer cover. To prevent self-electrification airship fabrics built up of several layers of diagonally doubled and specially gummed and varnished silk have more recently been used to good effect. "Gas Tightness" of Fabrics. The rubberized fab- ric used in airship hulls is theoretically gas-tight ; in practice, however, as hydrogen absorbs the air and diffuses through osmosis, allowance must be made for a daily leakage of from one half to one per cent, of the volume. The only really gas-tight material is gold-beater's skin, which is used in the gas-cells of Zeppelin airships ; unfortunately this material has a .low tensile strength and is, furthermore, not as impervious against water as it is against gas so that it cannot be employed to advantage in the con- struction of pressure hulls. On structure airships, where there is an outer cover to protect the gas- cells against the weather, the use of gold-beater's skin is, on the contrary, very satisfactory, although its cost is very high. The Ripping Panel. All pressure airships are provided with a ripping panel whereby the hull can almost instantly be deflated, should the wind prove too strong to permit mooring in the open. The ripping panel, of which there may be several on a large airship, consists of a strip of rubberized fabric which is applied over a vertical seam in the hull. It is operated by a ripping cord which its bright red color easily distinguishes from the rest of the operating cords. The system of construction of structure airships obviously prohibits the use of a ripping panel. The Understructure of Pressure Airships. The understructure of an airship is the part situated underneath the hull proper, which affords accommo- dation for the machinery (engines, transmission, propellers, fuel, oil, and water-tanks, dynamo, ballonet-blower, etc.) and the crew. The machinery and crew are housed on most pressure airships in one 'or more cars which are suspended from the hull by means of rigging guys, whereas on most structure airships the cars are rigidly connected with the hull frame. According to their system of suspension, pressure airships may be divided into the following sub- types : (i) The girderless type, in which the load, rep- resented by a short car, is directly distributed over the hull by means of steel cables ending at the top in crow's feet of flax rope, which are toggled to a rigging band of canvas, sewn upon the bottom of the 12 hull . The rigging band may further be strengthened by canvas belts passing around the hull. This type was originated by Major von Parseval. (2) The car-girder type, originated by the late Colonel Renard, in which the load is distributed over the hull by means of a trellis girder, extending up to two thirds the length of the hull, which is sus- pended by a rigging similar to the one above de- scribed, although the rigging band may be omitted. Only part of the girder is fitted as a car proper in this case, the great length of the girder serving primarily to reduce the bending moment. A diverg- ent application of this principle consists in fitting a short car with fore-and-aft outriggers, which serve the same purpose as a trellis girder, with a consid- erable saving of weight, however. (3) The keel-girder type, in which the load, rep- resented by a short car, is distributed over the hull by means of a girder, attached to the bottom of the hull, from which the car is suspended. There exist many divergent applications of the keel- girder principle. On the original keel-girder airship, the Lebaudy, designed by the eminent French aeronautic expert, M. Henri Juillot, the girder consisted of an oval platform of steel tubing which was built into the underside of the hull and held in place by internal crow's feet. On a later ship, the Morning Post, the girder was long and narrow, built in two pieces, hinged and suspended a short distance from the hull. The Gross-Basenach airships (Prussian Army Airship Works) are built on the same principle. The considerable head-resistance such a sus- pension generates led Italian airship-builders to seek and find a different solution of the problem. In the Italian Army airships, designed by Captains Crocco and Ricaldoni, the so-called "-girder" is nothing but a Gall's chain of considerable propor- tions, which is inserted between two layers of fabric on the bottom of the hull. Thanks to its being articulated, this girder closely follows the hull's curvature, allowing for longitudinal, but not for lateral, play. It realizes a method of suspension which gives for the same amount of air resistance a better distribution of load than the girderless type of airship, which it outwardly resembles. On all the foregoing keel-girder airships the car is suspended a considerable distance below the hull by a rigging of steel cables. The minimum of air resistance not only for the keel-girder type, but for any pressure airship as well, is attained on the Forlanini airships. There the cable rigging is entirely done away with, for the car is closely adherent to the hull. The keel-girder, to DIAGRAM OF THE 7,000 CBM. LEBAUDY AIRSHIP CAPITAINE-MARCHAL (KEEL-GIRDER, PRESSURE TYPE). H gas container; B ballonnet; C girder; M car; P air discharge pipe; Ho elevator; T fuel tank; F landing pyramid; S rudder; Gli- 3 stabilizer planes; e ballonnet partitions. which the car is rigidly connected, consists of a triangular lattice-work of steel tubing which follows the curvature of the hull's underside from stem to stern. The front end serves to stiffen the nose and holds the air intake valve in place ; the rear end car- ries the steering group. This girder, which is en- tirely rigid, is inserted into a longitudinal slot pro- vided in the hull and is supported by a crow's feet rigging from a suspension band which is situated in the centre-line of the hull. (4) The tension-truss type, created by the Span- ish engineer Leonardo Torres-Quevedo, in which the load is distributed over a hull of trefoil section by means of a flexible truss contained within and a cable rigging attached thereto. The tension truss consists of three cables, run- ning from bow to stern, which are carried in fabric pockets sewn to the hull at the intersection lines of the three lobes, and are trussed to one another by flax ropes and fabric strips. When the hull is under pressure, the truss is under tension and acts as a perfectly rigid girder, which distributes the load of the car or cars uniformly over the entire hull. The car is hung to 'this girder by a limited number of cables, the crow's feet of which are toggled within the hull to the lower sides of the triangular girder. Thanks to this feature, not only is the air resistance reduced to a great extent, but large airships of this type can be kept rigid when under way with an excess of pressure of only .15 mm. of water, whereas all other pressure airships require an average pressure of from 25 to 30 mm. of water. It is obvious that, since the load is evenly dis- tributed over the hull, each portion of buoyancy carrying a proportionate amount of load, the bend- ing moment will come very near being nil, which is the ideal condition sought. Furthermore, owing to the much lower internal pressure required, the hull is subjected to stresses and strains of much smaller value than on other pressure airships; con- sequently the life of the hull is increased, and lighter fabric can be used in its manufacture. The only apparent drawback of the "poly lobe" hull is that the surface area exposed to the relative wind is greater than for a hull of circular cross- section, so that the skin friction is proportionately increased. The Understructure of Zeppelins. The above considerations hold true to an even greater extent in the case of structure airships. There the hull frame forms a permanently rigid girder over which the loads can more uniformly be distrib- uted than over a pressure hull. One can dismiss with a few words the Schutte-Lanz type, in which the hull carries the cars on a cable suspension, since it embodies one great drawback of pressure a^ships the avoidance of which should be and is one of the principal points in favor of true structure airships. This drawback is the position of the pro- pellers, which are, except in the case of the For- lanini airships, applied too. far beneath the centre of resistance. As a consequence, airships of the suspended-car type have a tendency to drag the hull behind, thus causing disturbing couples, which must constantly be corrected by the control organs. On true structure airships, such as the Zeppelin, the cars are rigidly connected with the hull and at but a little distance, so that the propulsive apparatus can furnish its maximum of efficiency. Prior to the Great War the Zeppelin airships had a V-shaped keel protruding from underneath the hull, which formed the vessel's backbone and was fitted as a gangway affording passage between the engine cars. In the gangway there were the fuel- and oil-tanks, which fed the Maybach engines, these driving two sets of. twin-screws stayed on outriggers. In the middle the gangway flared out and formed a spa- cious compartment which served on passenger air- ships as a cabin-car, seating twenty -four; on mili- tary airships the compartment was divided into a wardroom for the convenience of the officers, quar- ters fitted with hammocks for the crew, a wireless room, and a photographic cabinet. Lavatories were provided on both types of airships. A lookout post, permitting astronomical observa- tion as well as the mounting of aeroplane-defense guns, was provided on the top of the hull, near the bow. This platform, about three meters square and provided with -a hand-rail, communicated with the forward car by means of a stairway which was in- closed in a shaft of aluminum plating and led right through the hull between two gas-cells. On the latest known type of Zeppelin various alterations are embodied in the understructure. The V-shaped keel no longer protrudes from the hull; the bottom is flat, and the gangway is built up within the hull in the form of an inverted V. Ob- viously a corresponding portion of the drum-shaped gas-cells is cut away. The cars number four and are arranged crosswise: the fore and aft cars ar coaxial, the remaining two cars, nicknamed "power- eggs," being mounted amidships right and left of the hull. The classic double twin-screw drive of ante-bellum Zeppelins is displaced by four pusher- screws, of which there is one on each car, each being driven through a clutch and change-speed gear by a 240 h.p. Maybach engine. The after car houses, however, two more such engines, which drive 16 through" bevel gear shafts a pair of twin-screws stayed on outriggers. The cars are built up of lattice girders similar to those used in the hull frame, and are covered with corrugated aluminum sheeting 2 mm. thick. The forward car comprises three compartments; the one foremost serves as a chart-room and com- mander's cabin, next to which comes. a small wire- less room, the rear compartment constituting the first engine-room. The "power-eggs" and the after car serve chiefly as engine-rooms ; the after car may also afford quarters for the crew. There are two gun emplacements on the roof, one, near the bow, mounting two 12 mm. guns on collapsible tripods and affording to each gun an arc of fire of 1 80 degrees from the center line, and one near the stern, aft of the rudder, mounting a Maxim. Six more guns of this type are mounted on the cars ; namely, two each on the fore and aft cars, and one each on the "power-eggs." Sixty bombs are carried amidships on two racks situated underneath the gangway. The bombs are released by an electro- magnetic gear from a switchboard in the chart-room. The release device can also be worked by hand, though in either case a sliding shutter must first be opened to allow the bombs to drop. Stability, Trim, and Steering. An airship is, when in motion, subject to rotation around "three axes, transverse, vertical, and longitudinal, which cause the airship to assume oscillating movements. . These are, respectively, rotting, yawing and pitching and in order to keep an airship to a true course it is necessary to possess means with which to check these oscillations. Rolling is automatically checked on all airships by having the load underneath the lift, thus placing the centre of gravity below the centre of buoyancy. Yawing is counterbalanced on all modern air- ships by means of vertical fins, and pitching by means of horizontal fins. It is customary to mount these fins directly on the hull, near the stern, or a little distance below it so as to bring them in line with, and a great distance from, the centre of resis- tance. In this respect structure airships possess a distinct advantage over pressure airships in that the fins may be rigidly mounted on the hull frame, whereas on a pressure hull the fins must be stayed by an elaborate truss, which is furthermore depend- ent for its rigidity upon the hull's ability to main- tain its shape. This is why on most keel-girder airships the keel-girder extends far back along the hull and carries the stabilizing fins, a solution which must unreservedly be preferred to that, customary DIAGRAM OF THE P. TYPE AIRSHIPS OF THE ITALIAN ARMY AIRCRAFT WORKS (KEEL-GIRDER PRES- SURE TYPE). V gas valve; B ballonnet; G car; St stabilizer and rudder; aa articulated keel-girder, carried in pocket bb; cc keel-girder links. In the left-hand corner a plan view of part of the keel-girder. 18 on car-girder airships, of mounting the fins on the end of the girder a considerable distance below the hull. The tendency in fin design is at present toward simplification, such as is displayed by the cross- shaped fins, which are gradually displacing the mul- tiplane and cellular fins of the last few years and the inflated fins of still-earlier days. The raison d'etre of the latter was chiefly their ability to lift their own weight; inflated fins did not, however, prove of efficient action and greatly increased the air resistance. The steering of an airship in the horizontal plane that is, sidewise is effected by means of a rudder similar to that used on ships. This rudder is gen- erally of the balanced type, to facilitate manual control, and is mounted in the wake of the vertical fin. In some cases multiplane rudders are em- ployed. Steering sidewise may also be assisted by swivelling-screws. Steering, in the vertical plane that is, up and down is effected in a great variety of ways. An airship can ascend through purely statical means, like a spherical balloon, by jettisoning ballast; but this manoeuvre is never made use of alone, because it is slow and involves much loss of ballast. The proper way for an airship to ascend is to alter its trim, whereby the bow will point upward, so that the pull of the air-screws will be applied at an angle to the horizontal. It is true that the latter object may be attained without change of trim by means of swivelling screws, which can be inclined at the angle desired; but this kind of ascent is highly in- efficient, because it increases to an appreciable ex- tent the projected area of the hull relative to the line of flight, thus creating additional air resistance. Changes of trim can be effected by static or dy- namic means, or by a combination of both. Static control of trim may be attained through a shifting of the centre of buoyancy or of the centre of grav- ity. In the first case the hull is provided with two ballonnets which can respectively be pumped full of air ; thus, for ascending the rear ballonnet is pumped full and the front ballonnet emptied, and vice-versa. The difference between the specific weights of hy- drogen and air causes in the ascent the centre of buoyancy to move forward, which in its turn raises the nose of the airship. This is the system employed on the Parseval and Gross-Basenach air- ships; it is worth noting that on both types addi- tional trim control is secured by a simultaneous shifting of the centre of gravity. On the Parseval airships this is effected by the car itself, which can move back and forth a distance of 0.75 m., owing to the car's main stays passing under rollers. This fore-and-aft motion is limited by appropriate an- chor-stays. On the Gross-Basenach airships the centre of gravity is displaced by trimming-tanks, which are filled and emptied by compressed air. The double-ballonnet system, besides being of very efficient action, has the further advantage of afford- ing means for checking the disequilibrating moments which the sudden surging of hydrogen toward the high side may generate. Additional means for checking this tendency are found on most pressure airships in the form of fabric partitions. The trim can also be controlled by dynamic means through the use of lifting planes (elevators) which raise or depress the airship's nose by virtue of the pressure onrushing air exerts upon them. This system is principally employed on structure airships where the under side of the hull affords a considerable amount of lifting surface when in- clined to the line of flight. On a 20 ton Zeppelin airship 2 tons may thus be added to the static lift, in which case the airship is, at the moment of start- ing, actually heavier than air. On the Zeppelin airships the action of the lifting planes is seconded by static trim control. Prior to the war this was effected by a shifting of the center of gravity. For this purpose the gangway of the early Zeppelins was fitted with a track on which a small lorrie carrying tools and spare parts could be moved back and forth. This primitive system was discarded in 1909 in favor of water- ballast trim, the water being carried in rubber bags which were suspended in the gangway. On the latest known Zeppelins the trim appears to be also controlled by a displacement of the center of buoy- ancy, each gas-cell being provided with a ballonnet whereby the volume of gas can be increased or reduced at will. Since the low tensile strength of gold-beaters' skin, which is the material used in the gas-cells, does not permit the storage of hydro- gen under pressure, all excess or deficiency of gas is regulated by the aforementioned compensating tank (see p. 4). This system, which is nothing but an application of Parseval's double-ballonnet system to the cellular construction, appears on the main as very efficient, for the ascensional speed of the latest Zeppelins is given by Swiss publica- tions as being a thousand meters in three minutes, two thousand meters in eight minutes, and three thousand meters in fifteen minutes. Volume, Displacement and Lift. It has been said before that an airship floats in the aerial ocean, as ships float on the sea, by virtue of buoy- ancy. A clear comprehension of the laws of the DIAGRAM OF THE 9,000 CBM. ASTRA AIRSHIP ADJUDANT-REAU (CAR-GIRDER PRESSURE TYPE). A envelope; B ballonnet; C stabilizer planes; D air valve; E gas valve; F elevator; H tractor screw; I side propeller; K transmission; M engine; N fuel tank; O oil tank; P chart room; Q instrument board; R engine room; S passenger compartment; T landing carriage; U ripping panel. 21 atmosphere is absolutely essential for understand- ing and comparing airship performances. It will therefore repay the reader to read the present chapter in its entirety. At normal barometric pressure (760 mm.) and o Centigrade I cubic meter (cbm.) of air weighs 1 .293 kg. ; an airship of 6,000 cbm. volume displaces consequently (6000X1.293 = ) 7758 kg. of air, or, roughly, 7.8 metric tons. This tonnage, called the normal displacement of an airship, affords the most convenient means of comparison between airships, because it is applicable to both the metric and English systems of measurement, and also because it permits the use of small values. The latter ad- vantage is particularly striking in the English measures, where an airship of 6,000 cbm. volume, which is a small vessel, is expressed in the imposing form of 211,800 cubic feet. Under the above-mentioned normal atmospheric conditions I cbm. of pure hydrogen weighs 0.090 kg.; that is, approximately 1.2 kg. less than an equal volume of air. For practical purposes the latter figure should, however, be reduced to i.i kg., because hydrogen cannot be produced in a totally pure state, and also on account of the par- tial deterioration (diffusion) of this gas under the influence of the air. The difference between the weights of equal volumes of air and hydrogen generates an equiva- lent lifting force which is caused by the upward pressure the displaced air exerts upon the hydrogen. It follows from the foregoing that I cbm. of com- mercial hydrogen possesses a normal lifting force, or "lift," of i.i kg. An airship of 6,000 cbm. volume has thus a normal lift of 6,600 kg., or 6.6 tons. By subtracting the lift of an airship from its displacement we obtain the weight of the hydro- gen contained in the hull. In the case of the above airship we have: Displacement 7.8 tons Lift. . . . .6.6 tons Weight of hydrogen i .2 tons Coal-gas, which is currently used for inflating free balloons, is much cheaper and much less in- flammable than hydrogen. It is, nevertheless, but little employed in airships, on account of its greater weight and obviously lesser lift. Coal-gas weighs, according to its degree of purity, from 0.520 to 0.650 kg. per cubic meter. It is customary to express the degree of purity of a gas in terms of specific weight. In that case the normal weight of I cbm. of air is assumed to be the unit in terms of which the weight of the gas 22 is expressed. Thus, for instance, a specific weight of 0.15 means that a given volume of gas is 0.15 times heavier than an equal volume 1 of air. Its actual weight is therefore 0.15 X 1.293 = 0.1935 kg., and its lift 1. 2931* 0.1935 = 1.0995 k S-. or approximately i.l kg. per cubic meter. The lift of an airship, as obtained by subtracting the weight of the contained hydrogen from that of the displaced air, gives the maximum weight an airship can lift for a given volume. The gross lift, therefore, comprises the weights of the hull, the under structure, the machinery, and the equipment. The difference between these weights and the total lift gives the useful load, which is made up of the fuel supply, the crew, and the military or commercial load. The Static Attitude of Airships. The lift of an airship may be considerably influenced by varia- tions of atmospheric pressure and temperature; hence all statistics of airships are based upon normal displacement and normal lift; that is, at 760 mm. barometric pressure and o Centigrade. Whenever the altitude above sea-level increases by 80 meters, the atmospheric pressure decreases by one per cent. The corresponding expansion of the air results in a decrease of the air's density whereby its- ability to exert lift is proportionately lessened. ,But- since hydrogen expands under the decreased atmospheric pressure in the same pro- portiori as air, it follows that the lessened density of the ^ff will be compensated for by an increased volume of hydrogen. Consequently an airship does not" lose any lift upon ascending as long as the gas is able to expand within the hull. The expansion of the gas within the hull is, however, necessarily limited by structural con- siderations. ; The low tensile strength of balloon fabrics, which is the logical outcome of the well- known weight-saving tendency applied to all air- craft, makes it imperative to prevent the hull from being subjected to conside able internal pressure, such as would arise through the expansion of the gas were the hull a totally sealed gas-container. This is why the gas-containing portions of all airships are provided with relief valves, which automatically open when the internal pressure reaches the safety limit. Such being the case, it becomes obvious that if an airship is to reach a certain level without loss of lift, it must be only partly inflated at sea-level. This initial deficiency of lift relative to the maxi- mum lift afforded by full volume must be compen- sated for, upon ascending, by throwing off an equivalent amount of ballast. DIAGRAM OF THE 9,000 CBM. CLEMENT-BAYARD AIRSHIP DUPUY-DE-LOME (CAR-GIRDER PRESSURE TYPE). ABD car-girder; C propeller outriggers; E elevator; F rudder; G engine; H clutch; I spring suspension of engine; J transmission; K propeller; L radiator; M fuel tank; N pilot stand; OO 1 ballonnets; P fan-blower; Q air discharge pipe; R gas valve; SS 1 air valves; U bumping bag; V mooring point; XXX ripping panels. The allowance for lift deficiency due to partial inflation greatly varies according to the type of airships. On structure airships the considerable weight of the hull frame generally limits the allowance for gas expansion to ten per cent, of the gas-cells' volume, a fact which eloquently demon- strates the need of large displacements for making structure airships efficient. The absence of a hull frame enables pressure airships, on the contrary, to embody a much greater allowance for gas expansion, the capacity of the ballonnet often attaining thirty-three per cent, that of the envelope. Since pressure air- ships are dependent upon internal pressure for the maintenance of their shape, variations of gas pres- sure being regulated by the ballonnet (see p. 7), it follows that the capacity of the latter determines the allowance for gas expansion and consequently the attainable altitude. It should be clearly under- stood that the ballonnet is nothing but a compensat- ing device for variable gas volumes, which endows the pressure airship with constant displacement up to the ballonnet's capacity of contraction or expan- sion. Structure airships can, on the other hand, do without a ballonnet, because the greater or lesser inflation of the gas-cells . does not affect the air- ship's displacement; the latter is, indeed, invariably constant, since it is determined by the volume of the outer cover, which is kept rigid by the hull frame. It has been said before that an airship loses in theory one per cent, of its lift whenever the altitude above sea-level increases by 80 meters; in practice, however, the stretch of the fabric and the not wholly isothermic expansion of the gas lower this ratio to such extent that one may assume the gas to expand one per cent, of its volume for every ascent of 100 meters. Thus, or instance, an air- ship which is ninety-seven per cent, inflated at sea-level can reach an altitude of 300 m. without loss of gas, provided the temperature of the air remains constant; but if it ascends to the 500 m. level, then the airship loses through the relief valves two per cent, of its lift, which must be compensated for by releasing ballast of equivalent weight. On descending from 500 m. to 300 m. altitude, the airship loses once more two per cent, of its lift; for, the gas having contracted in the descent, the gas container will be only 98 per cent, inflated. The resulting lift deficiency o" two per cent, must again be equalized by releasing ballast, unless it be balanced by an expenditure of fuel. The above example is drawn from the operation of commercial Zeppelin airships, which were normally navigating at the 300 m. level. Variations of the hydrogen's density are, owing to the small specific weight of that gas, of so little magnitude that it is customary to disregard their influence upon the static attitude of airships. Variations of barometric pressure affect the operation of airships in a way similar to those of atmospheric pressure. A 10 millimeters drop of the barometer corresponds approximately to an ascent of 100 m., and consequently to an expansion of the gas of one per cent, its volume, and vice versa. In practice it is, however, difficult to distinguish the influence of atmospheric pressure due to altitude from that of barometric pressure due to meteorological phenomena, since both kinds of pressure variations are recorded on airships by the self-same instrument; namely, the barometer. The static attitude of airships is furthermore affected by the temperature of the gas and that of the atmosphere. A rise of the gas temperature decreases the density of the gas and increases its volume. As a consequence, the gas weighs less and proportionately lifts more. Whenever the gas temperature rises 3 Centigrade, the lift of an airship increases by one per cent, of its volume, and vice versa. As an example, if means were provided on the above-discussed commercial Zeppelin wherewith to raise the gas temperature 6 Centigrade while the vessel descends from 500 m. to 300 m. altitude, it is obvious that no additional loss of lift would be incurred, since the previous loss of gas would be compensated for by a greater expansion of gas. On the other hand, if the gas temperature of this airship should rise 6 Centigrade at sea-level, then the maximum altitude the vessel could reach with- out loss of gas would be reduced to 100 m., because at sea-level the hydrogen would fill ninety-nine per cent, of the gas-cells' capacity. If the temperature of the atmosphere rises, the corresponding decrease of density and increase of the air's volume decreases the air's specific weight, and consequently its ability -to exert upward pres- sure upon a gas the specific weight of which re- mained stationary. A rise of 3 Centigrade in the temperature of the atmosphere decreases the lift of an airship by one per cent, of its volume, and vice versa. The altitude to which a ninety-seven per cent, inflated airship can normally ascend, as above explained, would thus be raised by 100 meters should the atmospheric temperature drop 3 Centi- grade. The foregoing considerations amply illustrate the magnitude of the losses of lift an airship may undergo at high altitudes or in a hot climate. 26 _ J-- I DIAGRAM OF A TENSION-TRUSS PRESSURE AIRSHIP, THE ASTRA -TORRES I. A envelope; BB ballonnets; C car; D propeller; E engine; F transmission; G fuel tank; H oil tank; I, K ballonnet blower; J air pipe; L rudder; M elevator; N, N ballonnet valves; O ripping panel. a airship fabric; bb rope girder; c, d, e, f, g, h, i crow's feet; jj rudder truss guys; k truss terminal; 1 truss hem; m, n, o, p rigging guys. 27 For instance, an airship which is ninety-five per cent, inflated at sea-level pressure loses, on reaching an altitude of 3,000 metres, and through the sole agency of decreased atmospheric pressure, 25 per cent, of its lifting force. This comes to say that a 24 ton Zeppelin lifts at said altitude only 18 tons, which is 6 tons less than the vessel weighed, fully loaded, at the moment of starting. As the useful load (weight of fuel, ballast, armament, and crew) of a Zeppelin amounts to one third its total weight when fully loaded, a 24 ton vessel should be able to lift a useful load of 8 tons, which may be apportioned as follows: Fuel for 20 hours (600 h.p.) 3 tons Crew of 14 .' i ton Armament i ton Ballast 3 tons Total 8 tons In view of the foregoing table it would at first sight seem that to reach an altitude of 3,000 meters a Zeppelin would not only have to jettison all of her ballast, but to exhaust her fuel supply as well, so that on reaching the desired altitude she would actually find herself adrift, deprived of means to progress and to control her altitude. Such would indeed be the case were the airship trying to reach said level fully loaded, and were she not endowed with dynamic lift. In practice a Zeppelin of the military (22,000 cbm.) type built prior to the Great War could reach an altitude of 3,000 m. and still retain a sufficient reserve of fuel and ballast by making up the 6 tons of lift deficiency partly by dynamic lift (2 tons) and partly by burning fuel and releasing ballast. An altitude of 3,000 meters, which could safely be reached after 12 or 14 hours of navigation, represents, nevertheless, for such a vessel the ultimate limit the roof, as the French say. With the development of anti-aircraft defense, this level has proved inadequate even relatively to safeguard an airship against high-angle guns and aeroplanes ; so the Germans were compelled, if they were to continue using Zeppelins, greatly to in- crease the latter 's ascensional power. Advices from neutral sources state that the Zep- pelins of the latest known type, built in 1916, dis- place 54,000 cbm., furnishing a total lifting force of about 60 tons, two thirds of which are taken up by the weight of the hull, the machinery, and the armament. Consequently 20 tons remain avail- able to lift the crew, the fuel-supply, and the ballast. The "roof" is variously estimated as being between 3,500 and 4,500 meters. The remains of the L. 33, which was brought down fairly intact in England, 28 DIAGRAM OF AN 8,000 CBM. PARSEVAL AIRSHIP, THE GRIFF (GIRDERLESS PRESSURE TYPE). 29 as well as observation by Allied aviators confirm the above data; indeed, Zeppelins engaged by Allied aviators at a 3,000 m. level have frequently climbed out of range, and the L. 39, which was shot down at Compiegne, was caught by the French gunners at an altitude of 3,500 meters. Now, assuming such a vessel to be fuelled for 20 hours at full speed, the following apportionment of the useful load might be established. Fuel for 20 hours . . . 7^ tons Crew of 22 ... . . ij^ tons Ballast . II tons Total ... 20 tons The loss of buoyancy of a 60 ton airship is 18 tons at 3,500 m. altitude and 24 tons at 4,500 m., or 30 and 40 per cent, of the total lift, respectively, always assuming a 95 per cent, inflation. This means that even supposing the dynamic lift amounts to" 6 tons a rather optimistic estimate a 4,500 m. level can be reached only when the airship has nearly exhausted her fuel- and ballast-supply. Advantages and Drawbacks of Structure and Pressure Airships. Structure airships possess the following advantages and drawbacks over pressure airships: (l) Constancy of displacement due to a rigid framework, which maintains the hull's shape and prevents its deformation through a breakdown of the ballonnet-blower or impact resistance. Draw- back: the airship cannot be deflated on landing in " the teeth of a storm ; it is also likely to be damaged in a rough landing through impact with the ground. (2) Cellular construction, subdividing the lift- ing force into individual gas-chambers, much of which may be pierced without depriving the air- ship of considerable lifting force. Furthermore the size of an airship can easily be enlarged by increas- ing the number of compartments. (3) Double skin, affording protection against weather to the gas-chambers which can therefore be made of highly gas-tight gold-beater's skin. The outer cover also insulates the gas-cells to a certain extent against sudden variations of temperature. Drawback: the leakage of hydrogen may create a detonating mixture between the outer cover and the gas-cells. This can, however, be prevented by effi- cient ventilation. (4) Possibility of greatly increasing the all- round efficiency of airships by increasing their size, because in a structure airship the weight of the hull and understructure increases in a less proportion than the lift. The lift of an airship increases as the length multiplied by the square of the beam. In DIAGRAM OF THE 13,000 CBM. SIEMENS-SCHUCKERT AIRSHIP 5. 5. / (GIRDERLESS PRESSURE TYPE; RIGGING BAND REINFORCED BY A FLEXIBLE KEEL OF FABRIC STRIPS). DIAGRAM OF THE 3,600 CBM. KOERTING AIRSHIP M. Ill (CAR-GIRDER PRESSURE TYPE; OUTRIGGER SUSPENSION). DIAGRAM OF A 7,500 CBM. ASTRA-TORRES AIRSHIP (TENSION-TRUSS PRESSURE TYPE). A envelope; B stabilizer planes; C rudder; D engine; E pilot stand; F passenger compartment; G fuel tank; H propeller stays; I propeller. other words, by doubling the linear dimensions of an airship the resulting lift will be eight times as great. In a structure airship the weight of the hull and understructure will increase nearly in the same proportion as the lift, because the dimensions of the framework and the thickness of the fabric must proportionately be increased; but on pressure air- ships the weight of the hull or envelope must increase at a greater rate, because of the additional thickness of material required to withstand the in- creased internal pressure. It follows that by in- creasing the linear dimensions of airships a size will be reached where the useful load of a structure air- ship will equal that of a pressure airship and whence the rate of increase will grow in favor of the former. The pressure airship here considered is one of the tension- truss type, which has a very low or vir- tually no bending moment. This is an important point, because the bending moment increases as the weight multiplied by the length of the hull, which is to say that by doubling the linear di- mensions of an airship the bending moment will be sixteen times as great. This consideration alone should be a convincing argument in favor of limit- ing the size of pressure airships in which the load is not uniformly distributed over the hull. On a properly designed airship the weights should be so distributed that the bending moment be virtually nil. If such be the case, and this is more easily attained on structure airships than on pressure air- ships, the weight of the hull and understructure will increase at a rate much nearer to the linear di- mensions than to their square. The result would obviously constitute a net gain in useful load. At present the useful load of the most efficient pressure airships, those of the Astra-Torres system, varies between 45 and 50 per cent, of the total weight, whereas a Zeppelin airship carries only about 33 per cent, of useful load. Apportionment of Useful Load on a 23,000 cbm. Astra-Torres airship.* Crew of 18, equipment, etc 2,040 kgs. Fuel, oil and water for a 20 hour flight . 4,400 kgs. Armament 600 kgs. Ballast 5,060 kgs. Total 12,100 kgs Apportionment of Useful Load on a projected 22,000 cbm. Parseval airship.* Crew of 15 1,200 kgs. Equipment, search-light, etc 140 kgs. Radio and cabinet 250 kgs. Fuel, oil, and water for a 20 hour flight. 3,600 kgs. Armament 500 kgs. Ballast 2,310 kgs. Total 8,000 kgs. * Prom official sources. 33 Airship Harbors and Mooring Stations. The operation of airships necessitates the establishment of specially adapted airship harbors, fitted with sheds, repair works and hydrogen plants, where air- ships can find shelter in case of bad weather and hydrogen for refilling their gas-chambers, and where minor repairs can be effected. Prior to the war, Germany's airship harbors had come to be known as models of their kind. Experience, dearly bought by a score of disasters to Zeppelin airships, taught the Germans so to build airship sheds that their entrance would lay in the direction of the prevailing winds. Where the winds are apt to change their direction suddenly, such as on the seashore, elaborate and very costly revolving sheds were provided, which could be turned into the prevailing wind, thus enabling an airship always to enter the shed with a head wind. The possibility of an airship being caught in a side wind and thrown against the shed, where she would break her back, was thus greatly obviated. The landing was further facilitated by electric- or gasoline-driven lorries running on tracks, which extended a whole airship length in front of the shed; on landing, an airship would throw her handling guys, which would be fastened on the lorries, and be promptly towed into the shed. The organization of docking facilities for airships was undertaken in Germany not only by the mili- tary and naval authorities, but also by municipal- ities and private concerns, thus giving an admirable example of progressive foresight. Mooring sta- tions, where an airship could weather a storm in the open, were also provided in large numbers. The British Navy has evolved a particularly promising mooring mast, which permits an airship to put its nose into a revolving cup wherefrom it can swing freely and follow the direction of the pre- vailing wind. This system has proven very satis- factory in practice because it lessens the risk of a downward air current throwing the airship against the ground. Where no such nose-cup is available a simple mast will answer the purpose, provided the airship is fitted on the nose with a mooring attachment. On structure airships as well as on the pressure air- ships of the Astra-Torres and Forlanini types the forward end of the hull frame or of the truss girder gives a solid mooring point wherefrom all traction is evenly distributed over the hull. On the girder- less Parseval airships the nose is reinforced by an internal metal cup. An interesting type of airship shed is that pre- sumably adopted by the German Navy for the air- 34 ship harbor of Heligoland, which is made to open sidewise, like a mouth, and receives an airship from above. The considerable cost involved in the construction of modern airship sheds seems to point to the ultimate adaptation of natural re- sources, such as deeply cut valleys, for airship har- bors. The Future of the Airship. The question is often asked, and it is quite pertinent in view of the stupendous development of the latter day aero- plane "What is the airship's future?" To the military aspects of this query the reader may find a rather exhaustive reply in a subsequent review of the services the airship has rendered in the Great War and the functions it may fulfill in the near future. There nevertheless remains the commercial side of the problem to be answered. Aeroplane constructors who are the natural adversaries of the airship point with a pride not illegitimate to the considerable velocities dynamic aircraft have attained of late, and which is double that of the swiftest airship, as an argument against the latter's commercial future. Further emphasis appears to be given this argument by the recent suc- cessful development of large weight-carrying aero- planes. Without going into a detailed discussion of these claims one might remark that whereas the safety of the passengers is quite an interesting item in public transportation the airship appears on the main to fulfill this condition to a far greater degree than the aeroplane, since the airship is capable of staying aloft regardless of engine failure, a thing the aeroplane cannot and,. probably, will not do for some time to come. This feature, which enables the airship to outride a storm if a landing proves im- practicable, should eventually prove a valuable asset for oversea voyages where the matter of alighting on the sea during a storrn appears all but a pleasant prospective. And, finally, it should be remembered that the development of the airship has by no means kept pace with that of the aeroplane; this being mainly due to the important expenditure involved in the construction of airships. Nothing could better illustrate this fact than the humorous zoological parallel one of the cleverest contemporary writers on aeronautics, C. G. Grey, editor of the London Aeroplane, has drawn between the airship and the aeroplane, and the mammoth and the dog, respectively. "The mammoth, breeding once in ten years or so, and running a hundred years or more to the 35 X XJJX r< \ r, DIAGRAM OF A 15,000 CBM. FORLANINI AIRSHIP (KEEL-GIRDER PRESSURE TYPE) generation, has developed no further than the ele- phant, who is an unfinished sort of job at his best, whereas the dog, breeding two or three times a year, and averaging about seven or eight years to the generation, is a very highly developed animal, and is, incidentally, capable of scaring the life out of an elephant." As a conclusion, one may safely assume that whatever the ultimate issue between the airship and aeroplane be, the immediate future, that is, the post-bellum period, will see the aerial ocean filled with a respectable number of passenger and pleasure airships, not to speak of those devoted to military- pursuits. 37 \\ N /X/YTTTI v-x J^LU DIAGRAM OF THE 2,200 CBM. SCOUT AIRSHIPS OF THE U. S. NAVY. I envelope; 2 car; 3 ballonnet; 4 blower intake pipe; 5 blower engine; 6 main air discharge pipe; 7 air pipe to ballonnet; 8 air mani- fold; 9 operating cord of ballonnet exhaust valve; 10 operating cord of butterfly valve; n pressure relief valve; 12 gas control valve; 13 operating cord of gas control valve; 14 twin-rudders; 15 king-post; 16 steering gear leads; 17 bracing wire; 18 elevator; 19 elevator leads; 20 stabilizing planes; 21 double patch; 22 suspension; 23 rigging (or belly-) band; 24 webbing; 25 ballonnet suspension; 26 nose reinforcement; 27 ripping panel; 28 ripping cord; 29 grab ropes; 30 weights; 31 mooring rope; 32 sight holes; 33 patch for removing bal- lonnet; 34 kapok floats; 35 fuel tanks; 36 exhaust silencer; 37 trimming tanks; 38 operating cords for trimming tanks; 39 guides for oper- ating cords; 40 filling hole and doubling patch. 38 THE AIRSHIP IN THE GREAT WAR The Ante-bellum Airship Programs. A large weight-carrying capacity, permitting to carry fuel for long cruises or powerful explosive's in the form of bombs or torpedoes for shorter raids; the possibility of drifting noiselessly with the wind and of hovering over a given point for observation or attack; the steady gun-platform afforded by the great buoyancy ; and, finally, the possibility of send- ing as well as receiving wireless messages all these seem to outline the large structure airship as the capital fighting craft of the air. Such was, prior to the war, Germany's concep- tion of the military airship, and her determined effort to become supreme in the air by just such a fleet materialized in 1913 in a building program which provided for the construction, within four years, of thirty airships for service with the Army and ten airships for service with the Navy. The Army air- ships were to form five squadrons, the Navy airships two squadrons; means for establishing an adequate number of airship harbors was also provided in the expenditure. The naval expenditure was appor- tioned as follows: Construction of 10 airships $2,750,000 Construction of airship harbors $3,500,000 Maintenance of materiel $2,500,000 Total $8,750,000 It is worth noting that all the naval airships and the greater part of the army airships of this pro- gram were to be of the structure type (Zeppelin or Schutte-Lanz) and of the largest size (24 tons end over). Cleared for action, these airships would possess an endurance of from 1,600 to 1,750 kilo- metres; carry one ton of munitions with which to supply their bomb tubes and machine guns; ballast enabling them to reach, partly lightened by fuel consumption, an altitude of 2,500 metres; and wire- less apparatus having a range of 300 kilometres in 39 daytime. Provision was also made in the program for the automatic replacement of airships lost through accident or having reached the age limit of four years. When the war broke out three ships of the 1913 program had been commissioned, and eight more Zeppelins, not to count minor units, were available from previous programs. Of the Allied countries, France possessed the largest and most efficient air- ship fleet; unfortunately, all but one of her' vessels were of the pressure type, of medium size, and slow speed, and consequently devoid of a great cruising radius. The only structure airship was, further- more, an experimental vessel. There was, to be sure, a building program, dating from 1912, which was to provide seven large pressure airships (of 25 tons and over) to the Army ; but none of these ves- sels was commissioned in August, 1914, and no allowance had been made for naval airships. In Great Britain the situation was still worse, for the airship fleet was nearer to be than in being. Prior to 1914 the Army possessed a few airships, and these were very small and short-ranged vessels indeed; the Navy had no airships at all, if one ex- cepts the experimental structure airship ordered in 1910 from Messrs. Vickers, Sons and Maxim, which proved a failure, and was therefore never com- missioned. The rebirth, or, rather, the creation of Great Britain's airship fleet dates from Mr. Win- ston Churchill's arrival at the Admiralty in 1913. At the instance of this far-seeing minister the still serviceable Army airships were placed under con- trol of the Navy, and orders were passed for the construction of two large structure airships and ten medium-sized pressure airships. On war being declared, two of the latter were available for ser- vice. In Italy conditions paralleled those of France. A few excellent pressure airships of medium size were in commission, and four capital airships of the largest size (from 25 to 40 tons) were building or projected. As to the Russian airship fleet, it was chiefly remarkable for its heterogeneous materiel, hailing from Russian, French, and German yards; its personnel possessed, in contradistinction to the aforenamed fleets, only the rudiments of training and little practical experience. Austria had no airship fleet. Early Airship Operations in the Great War. The foregoing picture of Europe's airship situation in the summer of 1914 is indicative of the over- whelming potential means the Hun possessed for strategical reconnaissance in those terrible first few weeks of the war when his hordes were overrunning 40 heroic Belgium and the northern departements of France. As a means of quickly gaining and report- ing information about the movement of troops, munition columns, etc., the Zeppelin proved a matchless instrument to which the German Army must owe many a success. The smooth working of the Zeppelin fleet was further facilitated by a total lack of any efficient Allied anti-airship defense system. Anti-aircraft guns, and principally range- finders, were still in their infancy; and destroyer- aeroplanes, which were to blow up the airships with incendiary bombs or darts, existed mainly in popular fancy. Germany's naval airships proved equally for- midable, for though little has come to be known about their reconnaissance work, one of them was "iron-crossed" for "cooperation with a submarine in a successful attack on three British armored cruisers," as the Berlin version runs. The ex- ploit referred to was the sinking of H. M. ships Hague, Aboukir, and Cressy by the German sub- marine U. 9. In view of the undoubted military achievements of the Zeppelin it seems pitiable that its record should have been soiled from the very beginning of the war by the despicable practice of terrorizing peaceful populations through an indis- criminate destruction of lives and homes. The practice of dropping bombs on undefended towns and villages, which from sporadic attempts gradually developed into a highly systematized policy, can- not be qualified but as piracy and murder, and it is to be hoped that its perpetrators will not escape just chastisement when the Allied High Court as- sembles to pass upon such and similar acts com- mitted in the name of German Kultur. The losses incurred by the German airship fleet in the early part of the war, chiefly in the first nine months, were considerable. Some vessels were shot down, others were captured on their moorings, still others were destroyed by storms; but nearly all were lost through reckless handling by officers unfamiliar with war-time conditions or willing to take risks. Within the limitations imposed upon it by a peculiar building policy the "old" French airship fleet gave an excellent account of itself. Nothing could better illustrate the intrinsic value of the Gallic materiel than the exploit of a three and one- half year old Army airship, the Adjudant- Vincenot, which raised, only one month before the war, the world's endurance record for airships to thirty-six hours, thus beating the record previously established by a brand-new naval Zeppelin. Besides effecting numerous strategical recon- naissances of considerable value in the early "mobile warfare" which came to an end with the Battle of the Marne and the "race to the sea," French airships also made a number of offensive raids on. German communication lines, depots, and encampments. Most of these incursions were made at night, for the French quickly realized the great vu nerability of airships in daylight, when the huge hulls form an appreciably large target ; whereas by night an airship must first be discovered before she can be fired at. The British used their few airships to good effect in patrolling the Channel, thus affording their troop-ships efficient protection against surprise attacks by submarines. In this function airships have proved very efficient fleet auxiliaries, for their cone of vision increases in proportion to their ele- vation, and extends, furthermore, on clear days a goodly depth into the sea. It is true that with a choppy sea the range of deep-sea vision stops at the surface; but since a submarine cannot fire a torpedo without showing her periscope, it is obvious that the airship has still the better of it. By combining the deep-sea vision obtained from the car of an airship with the weight-carrying capac- ity and the variation of speed afforded by these craft, it should be possible to develop a submarine- chaser airship which would rid the seas of their terror by attacking the submarine with bombs or torpedoes. The question of accurately hitting the target would resolve itself into that of developing appropriate bomb-tubes and range-finders, a prob- lem which is bound to be solved sooner or later. The British and French navies now possess a large number of such submarine scouts, termed Blimps in the Royal Naval Air Service, and they are used very extensively in connection with harbor and coast patrol work, although their offensive value is still a matter of conjecture. The United States Navy will soon have such airships, an order for six- teen Blimps having been awarded several manu- facturers in 1917. Resuming the review of the first year of airship operations, it can be said to have been characterized by strategical and tactical reconnaissances and by coast patrol work. Offensive actions were of a sporadic nature and more or less of an experimental sort. The German Airship Offensive. The summer of 1915 saw the opening of Germany's long-heralded grand airship campaign against the British Isles, and the novel warfare thus launched gave the world the first intimation of the offensive power of capital airships. The main purpose of this cam- THE STERN OF THE 19,000 CBM. SCHUTTE-LANZ AIRSHIP 5. L. I. THE ELLIPSOIDAL SHAPE OF THE HULL IS NOTEWORTHY. paign was to be, in the opinion of authoritative German writers on military subjects, the gradual destruction of London and the consequent wearing down of Great Britain's nerve-centres. To quote Captain Persius, the German naval writer, "the chief use and object of the airship at- tacks on England consists in damaging military means and power of our most dangerous enemy. The idea of what are military forces is not a narrow one. Not only may bombs be thrown upon forti- fied places, war-ships, and workshops for making shells and ammunition of all kinds, in order to de- stroy them, but they are also intended to destroy places of economic importance which, if they re- main untouched, would add more or less to Eng- land's power to continue the war. To the economic places which -are looked upon as proper objects for bombs, such as railway docks and wharves, may be added coal and oil depots, electricity- and gas-works, buildings which serve for meteorological purposes when they are in military hands, such, for instance, as Greenwich Observatory. All these are valuable targets, and the list could be continued." Strategical considerations such as the above were surely in no mean way responsible for the launching of Germany's airship offensive against Great Britain; one might nevertheless point out that by that time the Western front had become .a very much alive barrier of highly efficient anti- aircraft guns and battle-aeroplanes which threat- ened to greatly curtail, f not altogether to stop, the Zeppelin's career of overland scout. And Germany so well realized this changed condition that most of her Army airships were sent to the Eastern front, where the Russians' little developed anti-airship defense system proved no match for them. Contrary to all expectations, and to inspired German press reports, the Zeppelin offensive did not start with a concerted attack in fleet formation. Instead of such a bold stroke, the Germans indulged for months in experimental raids on English coast towns, so that by the time London was actually attacked enough time had elapsed to enable the English to work out the rudiments of a defense sys- tem which practical experience, gained in successive raids, gradually brought to the highest point of per- fection. In the meantime the airship offensive proceeded month after month, claiming an ever-increasing toll of human lives and wrecked homes. For it is remarkable how ludicrously small an amount of strictly military damage the Hun airships were able to cause, notwithstanding highly colored semi-offi- cial German reports to the contrary effect; and 44 THE STERN OF THE 20,000 CBM. VICKERS AIRSHIP No. i (OR MA YFLY) AFTER THE VESSEL BROKE HER BACK. 45 military damage consisted mainly of delays in rail- way and harbor traffic, the stationing in England of anti-aircraft guns and aeroplanes which could otherwise be sent to the front and, lastly, general inconvenience resulting from darkened cities. The measure of turning out all lights on an impending Zeppelin raid, which was first applied in London, proved a fairly good stratagem for misleading the raiders as to their whereabouts, since most of the incursions took place on dark, moonless nights ; and gradually the more important manufacturing and shipping towns of England were darkened in their turn. To complete these measures of safety, the names of places raided by airships were strictly withheld by the censor, thus depriving the enemy of all useful information. For a whole year the Zeppelin raids continued without showing signs of abatement, although a few airships had been destroyed on their homeward voyage through being intercepted by British avia- tors stationed on the Continent. Still, this was not quite a satisfactory defense system, since it punished the Hun only after he had accomplished his purpose. On their part, the German Admiralty seemed in no way satisfied with the results achieved by their airships, for in the spring of 1916 orders were given to the Zeppelin factories for the construc- tion of a number of vessels twice the size of those laid down in 1914, and with which a decisive stroke was to be made against London. The stroke totally miscarried, for the Zeppelin raids which began toward the end of August, 1916, ended for the enemy in an unparalleled series of disasters. Three airships of the largest size were brought down by anti-aircraft guns and aviators in September, and one in October, all around Lon- don; and when, discouraged by so grievous losses, the Germans in the following month sent an airship squadron against the Eastern Counties, which they believed to be less well protected, British aviators added to their bag of airships two more Zeppelins, which they sent in flames into the sea. Tacit ad- mission of the failure of German's second airship campaign against Great Britain may be found in the following comment by the above-quoted Captain Persius: "It would be premature to express any decided hope as to whether airships can be of any decisive influence upon the conduct of the war." And as if the German Admiralty wanted to con- firm this opinion, extended Zeppelin raids on Great Britain came to an abrupt end with the disastrous autumn campaign of 1916! During the first six months of 1917 only two isolated incursions of Zeppelins took place, one in 46 March and one in June, and each was marked by the destruction of one of the enemy airships. Capital Airships as Naval Scouts. The recent failure of capital airships to act as weapons of offense, as well as the growing difficulty attending to their employment for strategical reconnaissance over 'and, appears to limit their role to that of serving as naval scouts. It was Sir Percy Scott who first directed the attention of naval authorities toward this aspect of the Zeppelin's potentiality when he wrote, in 1909, the following prophetic words: "In gaining information of the locality, strength and disposi- tion of the enemy's fleet and so unmask his strategy . . . an airship's services would be invaluable, for it might not be possible to obtain the informa- tion in any other way." The large structure airship is truly an invaluable super-scout in naval operations, for its combined range of vision, speed, and cruising radius make it by far superior to any vessel afloat. Kite-balloons, carried on mother-ships, are of considerable value in spotting targets otherwise invisible to the gun- ners, but they are poor substitutes for long-range airships, whose speed and movements are independ- ent of naval vessels, whereas kite-balloons are moored to their carriers and therefore entirely dependent on the latter's speed. Nor can the pres- ent day seaplane be employed for cruising out to sea with a fleet, because (i) its range is still very limited and amounts in the best case to only one fourth that of a capital airship; (2) it cannot vary its speed or remain motionless in the air, and these requirements are often desirable for accurate ob- servation; and (3) it can neither start from, nor alight on, a really rough sea, where it could other- wise be refuelled from a tender. Against the above drawbacks of the kite-balloon and the seaplane the modern structure airship pre- sents the following advantages: (i) It can reduce its speed or altogether stop its engines and hover over a given place on a windless day, or else drift with a favorable wind, thus saving fuel; (2) its large cruising radius, which for a well-designed 60 ton vessel should amount to from 2,500 to 3,000 kilometres, provided only defensive armament, such as machine-guns, is carried; (3) the possibility of refuelling the airship from a tender at sea by means of a charging-pipe operated by compressed air the hydrogen could be renewed in the same way (4) it can operate by night as well as by day. The last, and not the least, argument in favor of the use of airships as naval scouts is their much lesser vul- nerability over the seas than over land. Over land 47 TOP THE MOORING MAST OP THE ROYAL NAVAL AIR SERVICE AIRSHIP LEAVING A SHED; BOTTOM- INFLATION OF AN AIRSHIP FROM A FIELD GENERATOR AIRSHIP WEIGHTED DOWN IN A SHED. 48 an airship runs the ever-present risk of being hit by an anti-aircraft gun, which may be masked by a bush, a tree, or any natural or artificial shelter and is therefore invisible from above; but on the sea a gun means a ship, and a ship can be detected, from an airship navigating at an elevation of 1,500 metres, in a radius of 100 kilometres, provided the weather is clear. And since the range of vision afforded from the top of a surface ship but seldom reaches 30 kilometres, it is obvious that an airship can leisurely reconnoiter an enemy squadron with- out even being seen by the latter. Surprise en- counters may naturally occur between airships and surface vessels, more specially if one of them sud- denly emerges from a cloud or fog-bank; but losses have to be expected in warfare. Furthermore, in the above contingency an airship, with her greatly superior speed, could in most cases .successfully outrun a surface vessel. The Great War has fully demonstrated the value of capital airships in naval reconnaissance work, for the strategical advantage possessed by the Ger- man fleet in various actions fought in the North Sea must almost entirely be attributed to the clever reconnoitering effected by Zeppelin flotillas. The element of surprise was thus in favor of the German battle-cruiser squadron when it raided Yarmouth, Scarborough, and Lowestoft, because it could ascer- tain the whereabouts of the British battle-cruisers by a squadron of far-flung Zeppelins, which would report every British move by wireless. In the Battle of Jutland the participation of Zeppelins enabled the German High Sea Fleet nearly to over- whelm Admiral Beatty's battle-cruiser squadron in the first phase of the engagement, and to break off the action after the British Grand Fleet had ar- rived on the scene in full force, thus turning an im- pending disaster into a fairly balanced draw. One may also assume that the repeated slipping of the British blockade by German commerce- destroyers, such as the Mowe and the Seeadler, has been made possible to a great extent, if not wholly, by intelligent cooperation with Zeppelins. How decisive the foregoing considerations are is best illustrated by the establishment, in 1917, of a joint board of officers of the United States Navy and Army, which has been ordered to lay down the plans for the first American capital airships. Not wanting to lag behind, the Japanese Navy decided at about the same time to lay down a 2O-ton airship of the structure type. Germany's Airship Production. Although Ger- many's war-time output of airships is shrouded, like all production of war materiel, by the veil of 49 military secrecy, it is assumed on good authority that the Friedrichshafen and Potsdam works of the Zeppelin Company are equipped to turn out one complete airship in three weeks' time. This rapid rate o^ construction is made possible by laying down several airships at a time, as well as by a strict standardization of the pieces which make up the hull frame, the understructure, etc. The Fried- richshafen works appear to mainly build the larger naval airships, while the army is kept supplied by the Potsdam branch. Little is known regarding the activity of the Schutte-Lanz Works; information from neutral sources places their recent rate of production at one airship every month, although their earlier output seems to have been considerably slower. It also appears that since 1916 the Schutte-Lanz works are exclusively building airships of the Zeppelin type. Knowing the approximate rate of construction of the Hun's principal airship works, that is, those where capital airships are built, it appears little difficult to figure out Germany's total production of capital airships during the war, provided the rate of output has remained the same. While the following table does not claim to be strictly accurate in regard to the apportionment of airship constructions to single yards, the yearly output since August ist, 1914, as well as the grand total herewith given, may eventually be found to have missed the mark by little. Confirmation of this view may be found in a Swiss report announcing the launching, in February, 1916, of the LZ. 95, that is, the ninety-fifth Zeppelin of current series, which number includes twenty-five airships built prior to the war. Works 1914 1915 1916 Total Friedrichshafen. . Potsdam 7 7 17 17 17 17 41 41 Rheinau s 12 12 29 Total . 10 46 46 in It may be noted that the above table extends only over the period ending with December 3ist, 1916. The reason for this is to be found in reports stating that the General Staff of the German Army decided in January, 1917, to discontinue the use of structure airships. If this report proves true, and there are good reasons to believe that it will, then Ger- many's production of capital airships will have suffered an obvious reduction, for the Navy will henceforth be its sole customer until such day when the construction of passenger - airships can once more be taken up. I. THE WORLD'S AIRSHIP BUILDERS Haen|em-"Haenlein" (1872) Renner - "Estanc" (1909) THE M. Ill (1911). 52 AUSTRIA Boemches (Captain F.)> Vienna. Builder of a pressure airship of the car-girder type. Girder consisting of a short car fitted with bow-outrigger only. Trim controlled by lifting planes and compensating ballonets. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h. P .) Speed (km) Notes l Boemches (1912) 57 9 2,750 72 40 Experimental airship. Two Koert- ing engines ; twin-screws. The air- ship did not prove satisfactory on her trials and was dismantled the following year. (Photo wanted.) Haenlein (Paul), Vienna. Builder of a pressure airship of the keel-girder type. Trim controlled by ballast. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes i Haenlein (December, 1872) 50.4 9.2 2,400 3 4.5 Experimental airship. One Lenoir gas engine fed by the foal-gas con- tained in the hull ; one pusher- screw. The trials disclosed the in- adequacy of the power-plant, which barely enabled the airship to make any headway. Koerting (Maschinenbau A. G.) Vienna. Builders of a pressure airship of the car-girder type. Girder consisting of a short car with two outriggers. Trim controlled by two compensating ballonets and trimming tanks, the latter being operated by compressed air. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes l M. III. (January, 1911) 68 10.5 3,600 150 49 Austrian Army airship. T\v:> Koerting engines ; twin-screws. Bal- lonets. 900 me. A fairly successful vessel. Was accidentally destroyed on June 20th, 1914, over Schwechat (near Vienna) through being ram- med by a military aeroplane. The crews of both aircraft perished. L_ 54 AUSTRIA Continued Motor-Luftfahrzeug Gesellschaft, Vienna. Builders of pressure airships to various designs. Works No. Name Trials Length 2 General Meusnier 70 9 3,400 45 Experimental airship, built to the designs of Col. Ch. Renard and his brother, Commandant P. Renard. Car-girder, pressure type. One gasoline engine ; one tractor-screw. Owing to the unreliability of the engine the airship, though complet- ed in 1893, could not be tested and was eventually dismantled. 3 Fleurus 77 13 6,850 160 60 French Army airship. Built to the {November, 1912) designs of Capt. Lenoir. Girderless pressure type. Two Clement-Bay- ard engines ; twin-screws. Best en- durance : 680 km. in 15 h. 30'. Named after the battle in which the first military use was made of a balloon (June 26th, 1794). The Fleurus made in the early part of the war numerous gallant raids on German R. R. junctions. 4 (Building) 110 15 17,000 1,200 80 French Army airship. Two Dan- sette-Gillet engines. (The herewith given data are unconfirmed, being based on Weyer's Taschenbuch.) 'Astra" (Societe de Constructions aeronaut iques), Billancourt (Seine). Builders of pressure airships to the designs of Messrs. Edouard Surcouf and Henri Kapferer (car-girder type) and to the patents of M. L. Torres-Quevedo (tension truss type). Trim controlled by lifting planes (Astra type) by ballonets on Astra-Torres type. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes l 2 Ville-de-Paris (November, 1906) 60.4 10.5 3,200 50 36 Hull of the Lebaudy-I. Excursion airship of M. Henri Deutsch de la Meurthe. Ballonet: 500 me. One Chenu engine ; one 61 Astra -"Ville-de-Paris" (1906) Astra -"ViNe-de-Pau" (1910) FRANCE Continued Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h. P .) Speed (km) Notes tractor-screw. Cylindrical fins. Best endurance in 1908: 260 km. (Paris- Verdun). Presented by her owner to the French Army after the loss of the Patrie. Suffered numerous mishaps and was again rebuilt and re-engined. Ballonet: 1,100 me. 2a (1909) 66 10.5 3,600 70 44 One Chenu engine. Served for years as a training airship and was eventually dismantled in 1913. 3 Ville-de-Nancy (June. 1909) 56 10 3,350 80 45 Excursion airship of the Compagnie Generale Transaerienne of Paris. One Renault engine; one tractor- screw. Ballonet: 1,100 me. Was laid down as Ville-de-Bordcaux. Made numerous ascents with pas- sengers. ' 4 Clement-Bayard I (October, 1908) 56.3 10.6 3,500 105 48 Excursion airship of M. Clement- Bayard. Ballonet : 1,100 me. One Clement-Bayard engine; one trac- tor-screw. Best endurance : 200 km. in 4 h. 53 min. ; altitude: 1,550 m. On concluding the latter test, on Aug. 23, 1909, the airship fell for lack of ballast into the Seine, but was salvaged, repaired and sold to the Russian Army who re-named her Berkout. Dismantled in 1913. 5 Colonel-Renard (July, 1909) 64.7 10.8 4,300 100 50 French Army airship. Named after the builder of the first successful airship. One Panhard-Levassor en- gine ; one tractor-screw. Ballonet : 1,500 me. Best endurance : 100 km. in l l /i hrs. Was re-fitted with twin- screws in 1911. 63 _J FRONT AND REAR VIEWS OF THE ASTRA-TORRES I (1911 64 FRANCE Continued Works No. Name Trials Length (m) Beam J m >_ Volume (me) Power (h.p.) Speed (km) Notes 6 Espana 64.7 10.8 4,200 120 50 Spanish Army airship. Ballonet : (October, 1909) 1,500 me. One Panhard-Levassor engine ; one tractor-screw. Best en- durance : 250 km. in 5 hrs. Was commissioned but a short time. 7 Ville-de-Pau 60 12.2 4,475 105 50 Excursion airship of the Compa- (April, 1910) gnie Generate Transaerienne. Bal- lonet : 1,000 me. One Clement-Bay- ard engine ; one tractor-screw. Made up to July 31, 1911, 273 trips, aggregating 8,000 km., on which 2,- 950 passengers were carried, chiefly at Pau and Lucerne. At the latter place the airship was named Ville- dc-Lucerne. Dismantled in 1912. 8 Ville-de-Bruxelles 74.5 14.3 8,300 220 52 Excursion airship of the "Avia" (July, 1910) Co. of Brussels. Ballonet : 2,460 me. Two Pipe engines driving one tractor-screw and one pair of twin- screws. First of a new series of Astra airships. Best endurance : 5 hrs. Made numerous trips over Brussels. 9 Astra-Torres I 47.7 8.4 1,590 60 53 Experimental airship, the first As- (March, 1911) tra vessel of the tension-truss type. Ballonet : 500 me. One Chenu en- gine driving one tractor-screw. Best endurance : 354 hrs. Was de- stroyed by a fire on Sept. 9th, 1912, in the air^port of Issy. W) Lieutenant-Chaure 83.9 14 8,850 240 53 French Army airship. Ballonet: 3,- (August, 1913) 200 me. Laid down to be of the I'ille-de-Bruxelles class, was altered during the construction and made 'milar to Adjudant-Reau, the bal- 65 TOP STERN VIEW OF THE ASTRA-TORRES I AND THE VILLE-DE-BRUXELLES; BOTTOM STERN VIEW OF THE CONTE AND THE ADJUDANT-REAU. 66 FRANCE Continued Works No. Name Trials Length (m) Beam (m) Volume (me) Power f five. la (September, 1907) 56.4 16 7,800 80 30 Re-built and re-engined with one Lorraine- Dietrich engine by the Mallet Works, to the designs of Mr. Vaniman. prior to trials. Pro- visioned for ten months. Made an ascent of 2 hrs. at Virgo-Bay (Spitzbergen) ; ran into a snow storm and was damaged on land- in e. 79 THE AMERICA (1906-08). 80 FRANCE Continued Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes ib (August 15th, 1908) 70 16 9,200 160 40 Re-built- and fitted with an addi- tional engine (E.N.V.) driving a second pair of twin-screws. Made a trip of 200 km. over the Polar Sea on her first ascent ; lost the equilibrator and fell into the sea, but was salvaged and shipped to Atlantic City, N. J., where she was re-fitted for a transatlantic trip, un- der the direction of Mr. Vaniman, and equipped with a lifeboat and wireless. Left Atlantic City on Oct. isth, 1910, headed for Europe, with a crew of five. Engine and equilibrator troubles forced the crew. to abandon the America after a voyage of 70 hrs., when the steamer Trent came to their assist- ance and took them off. Only the lifeboat- of the America was sal- vaged. 2 La Belgique Belgian excursion airship. Built to M. Godard's designs by the Vivinus Works of Brussels. (See Belgium.) Lebaudy Freres, Moisson pres Mantes (Seine-et-Oise). Builders of pressure airships of the keel-girder type to the designs of M. Henri Juillot. Keel-girder of steel-tubing, forming a rigid understructure. Trim controlled by lifting planes. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes i Lebaudy (November, 1902) 56.5 9.8 2,284 40 35 Experimental airship. Astra hull. One Mercedes engine ; twin-screws. Ballonet : 300 me. Was the first successful modern airship. Best en- 81 TOP THE LEBAUDY (1902-08) AND THE PATRIE (1906); BOTTOM THE LIBERTE (1909) AND THE CAPITAINE-MARCHAL (1911). 82 FRANCE Continued Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes durance : 98 km. in 2fi hrs. Re- fitted with a new hull, the air- ship made 12 ascents but was la Le handy II. 56.5 9.8 2,660 40 35 carried away by the storm on (August, 1904) Aug. 28, 1904, and badly dam- aged. Was repaired and eventual- ly rebuilt. Ballonet: 500 me. Re- sumed her ascents, but was again laid up for repairs of her hull, which had been torn by the storm Ib Lebaudy III. 56.5 10 2,950 50 35 when landing at the Camp de Cha- (July, 1905) lons. Reached on Nov. loth, 1905, twice in succession an altitude of 1,370 m. Her builders sold the air- ship to the French 'Army for the nominal sum of Frs. 80,000 ($16,- ooo) in December, 1905. Ic Lebaudy IV. 61 10.3 3,300 70 40 French Army airship, as rebuilt by (October, 1908) the Army Airship Works. Bal- lonet : 650 me. One Panhard-Le- vassor engine; twin-screws. Best altitude, 1,550 m. (in 1908). Was moored in the open for 17 days in the autumn of 1909. Dismantled in 1912. 2 Patrie 61 10.3 3,250 60 45 French Army airship. Ballonet : (November, 1906) 650 me. One Panhard-Levassor en- gine ; twin-screws. Best endurance : 2a .(November, 1907) 61 10.9 3,650 60 45 240 km. in 6|4 hrs., after recon- struction. Was carried away by the storm on Nov. 30th, 1907; foun- dered in the Atlantic. 3 Republique 61 10.9 3,700 70 50 French Army airship. Ballonet: (June. 1908) 730 me. One Panhard-Levassor en- gine : twin-screws. Best endurance 83 TOP THE CAR OF THE LEBAUDY; BOTTOM THE CAR OF THE CAPITAINE-MARCHAL. 84 FRANCE Continued Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h. P .) Speed (km) Notes (in closed circuit) : 210 km. in 7J4 hrs. Was destroyed in mid-air on Aug. 25th, 1909, through the break- ing of one screw which burst the hull. The crew of four were killed. 4 Lebedj (ex-Russie) (May, 1909) 61.2 10.9 3,800 70 49 Russian Army airship. One Pan- hard-Levassor engine; twin-screws. Ballonet : 900 me. 5 Liberte 65 12.5 4,200 120 45 French Army airship, as originally (August, 1909) laid down. Was modified, on ac- count of the disaster of the Rc- pitblique, before being commis- sioned. 5a (June, 1910) 84 12.8 7,000 120 53 Two Panhard-Levassor engines ; twin-screws. Designed endurance : 8 hrs. Dismantled in 1914. 6 M. II. Austrian Army airship. Built to Messrs. Lebaudy's designs by the Motor-Luftfahrzeug Gesellschaft of Vienna. (See Austria.) 7 Morning-Post 103 12 9,800 270 55 British Army airship, purchased by (September, 1910) a national subscription started by the London daily Morning Post. Ballonet : 2,500 me. Two Panhard- Levassor engines ; twin-screws. On Oct. 26th, 1910, the airship flew * from Moisson to Aldershot (370 km. in 5^/2 hrs.), but was damaged on being berthed. Re-commissioned a few months afterwards, the air- ship was wrecked through faulty j manoeuvring on May 4th, 1911, by- stranding in some trees. 8 Kretchet '" Russian Army airship, built to '* Messrs. Lebaudy's designs by the - Russian Army Airship Works. (See Russia. 1 ) 85 1 86 FRANCE Continued Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h. P .) Speed (km) Notes 9 Capitaine-Marchal 85 12.8 7,200 160 50 French Army airship. Two Pan- (March, 1911) hard-Levassor engines ; t w i n- * screws. Named after the com- mander of the ill-fated Republique; presented to the Army by her build- ers. Designed endurance : 10 hrs. Dismantled in 1914. 10 Lieut. Selle-de-Beau- 89 14.6 10,000 200 55 French Army airship. Two Pan- champ hard-Levassor engines ; t w i n- (October, 1911) screws. Named after a balloon ob- servation officer of the First French Republic. Designed endurance: 12 hrs. Best altitude: 1,685 m. 11 Tissandier 140 15.5 28,000 1,350 80 French Army airship. Nine Salm- (December, 1914) son engines mounted in groups of . three on three cars; three sets of triple-screws. Fitted with four ma- chine guns and wireless carrying 600 1cm. Designed endurance : 15 hrs. at 2,500 m. at full speed. 12 (Building) French Army airship. Tissandier- class. Le Berrier, Paris. Builder of a pressure airship fitted with a ballonet which was the earliest forerunner of the modern airship. Propulsion by means of twenty oar-propellers worked by the crew. Enterprise financed by the Comte de Lennox. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes 1 L'Aigle (August 17, 1834) 42.2 11.4 2,800 ? ? On her trial the airship proved too heavy to lift her own weight and was destroyed by the infuriated spectators. 87 Ro3e -" Castor -ei-Pollux" (1901) S* d'Aerostation - Malecot" (1907) 88 FRANCE Continued Le Compagnon (Armand), Paris. Builder of a pressure airship of the keel-girder type. Propulsion through flapping wings. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes l Le Compagnon (1892) 20.4 3.5 156 Experimental airship. No conclu- sive results were obtained. Robert & Pillet, Paris. Builders of a pressure airship of the keel-girder type. Trim controlled by lifting screws. Carton- Lachambre hull. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes 1 Robert-Fillet (1904) 38 9.5 2,100 35 ? Experimental airship. One Aster engine; swivelling twin-screws and one pusher-screw. The trials were not satisfactory and the airship was eventually broken up. Roze (Louis), Paris. Builder of a structure airship characterized by twin-hulls rigidly connected side-by-side. Aluminum frame. Trim controlled by lifting screws. Fabric skin. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h. P .) Speed (km) Notes 1 Castor-et-Pollux (September, 1901) 45 7.5 2,800 20 ? Experimental airship. One Buchet engine; two co-axial screws for horizontal propulsion and two lift- ing screws. The trials remained in- conclusive, being stopped for lack of funds after the second ascent, when the airship reached an alti- tude of 15 m. 89 Santos -Dumont -"N 1 (1898) Santos-Dumont -"N 2" (1899) Santos -Dumont -"N In February, 1917, the Prussian Army decided to discontinue the use of Zeppelin airships. L. 5 (November, 1914) L. 6 (December, 1914) L. 8 (February, 1915) L. 9 (March, 1915) L. 10 (April, 1915) 158 16.6 27,000 840 80 German naval airships.* LZ. 24 'type ; fitted with .more powerful en- gines. Endurance, fully loaded, 26 hrs. Crew of 16. Four Maxims on the cars; l'/ 2 tons of bombs. The L. 5 was destroyed on June 7th, 1915, in the airship shed of Evere (Belgium) by aeroplanes pi- loted by Flight Sub.-Lieuts. J. P. Wilson and J. S. Mills, R. N. A. S. The L. 6 was destroyed on the ^ame day near Ghent (Gand) by an aeroplane piloted by Flight Sub.- Lieut. R. Warneford, V. C, R. N. A. S. The L. 8 broke up on landing by night, on March 5th, 1915, near Tirlemont. The L. lo, while re- turning from a raid on England on Aug. roth, 1915, was wrecked in the harbour of Ostende by the Dun- kirk squadron of the R. N. A. S. * According to an article by "Austerlitz" in The Aeroplane, London, Jan. 3rd, 1907. 139 THE END OF THE L. 75 (1915). 140 GERMANY Continued Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes L. 11 (July, 1915) 160 17.5 30,000 1,050 85 German naval airships. Five en- L. 12 L. 19 gines ; two on each car driving (August to November, 1915) twin-screws, the fifth engine on the stern-car driving one pusher- screw. Designed endurance : 26 hrs. ; altitude : 3,500 m. Crew of 16. Four Maxims on the cars and one on the roof, near the bow. 2 tons of bombs. The L. 15 was damaged, while raiding England, by A.-A. guns and by Lieut. A. de B. Brandon, R. F. C., and came down on April 1st, 1916, in the mouth of the Thames, where the crew scuttled the airship and surrendered. The L. 18 caught fire and blew up on Nov. I7th, 1915, in the airship dock of Tondern. The L. 19 was damaged by A.-A. guns while raiding England and foundered on Feb. 2nd, 1916, in the North Sea with the entire crew. L. 20 L. 29* 170 20 35,000 1,260 95 German naval airships. Six en- (November, 1915, to April, gines ; triple-screws on both cars. 1916) Designed endurance : 30 hrs. ; alti- tude : 3,500 m. Crew of 18. Masked gangway, like on LZ. 18, fitted as a bomb-chamber. One 12 mm. ma- chine gun each on the roof near the bow and, one on the bow-car; two Maxims each on the cars and the bomb-chamber, firing broad- sides. 2 l /2 tons of bombs. * Minus L. 21, which was a Schiitte-Lanz airship. 141 THE END OF THE L. 20 (1916). 142 GERMANY Continued Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes The L. 20 stranded on May 3rd, 1916, near Stavanger (Norway), having run out of fuel and drifted with the wind while homeward bound from a raid on Scotland. The crew were interned and the airship was blown up by the Nor- wegian authorities as a measure of precaution. The L. 22 was shot down on May I4th, 1917,' in the North Sea, by a British seaplane. L. 30 L. 40 207 22 54,000 1,500 105 German naval airships. Six May- (May, 1916, to January, 1917) bach engines of a new model ; one pusher-screw each on the bow-car and central twin-cars ("power- eggs") and triple-screws on the stern-car. Designed -endurance : 30 hrs. ; altitude : 4,000 m. Crew of 22. Two 12 mm. machine guns car- ried side-by-side on the roof, near the bow, on collapsible tripods; one such gun on the roof, near the stern. Six Maxims, viz., two each on the bow and stern cars and one each on the twin-cars. Sixty bombs, aggregating 3^ tons, carried amid- ships on racks. Electro-magnetic launching device. Masked gang- way, connecting all stations. The L. si was shot down on Oct. 2nd, 1916, while raiding London, by Sec. Lieut. W. J. Tempest, R. F. C., and fell near Potter's Bar. The crew were killed. The L. 32 was shot down on Sept. 24th, 1916, while 143 TWO SCHEMATIC VIEWS OF THE L. 33 [LZ. ?6\ (1916). Courtesy of The A croplane. 144 GERMANY Continued Works No. Name Trials Length On) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes raiding London, by Sec. Lieut. F. Sowrey, R. F. C. The crew were killed. The L. 33 was disabled the same day by A.-A. guns and landed in Essex, where the crew scuttled the airship and surrendered. Two airships, apparently pertaining to this class, were shot down on Nov. a8th-29th, 1916: one off Durham by Sec. Lieut. I. V. Pyott, R. F. C., and one off Norfolk by Flight- Lieuts. E. Cadbury, G. W. R. Fane and Flight-Sub.-Lieut. E. L. Pull- ing, R. N. A. S. The crews of both airships were killed. The L. 39 was shot down, while homeward bound from a raid on England, by French gunners on March iyth, 1917, near Compiegne. The crew were killed. (Numbers unknown) 235 25 70,000 1,750 or 110 German naval airships. Seven or 2,000 eight engines ; same drive as on L. 30 class except for twin or triple- screws on the bow-car. Designed endurance : 40 hrs. ; altitude : 4,000 m. Armament: (i) four 12 mm. machine guns mounted in pairs on the roof, fore and aft (or in gun- embrasures) ; (2) six Maxims, like on L. 30 class. An airship of this class is said to have been destroyed by French avi- ators, on Sept. 22nd, 1916, in the airship dock of Rheinau ; another airship of this class appears to have been wrecked in a storm on Nov. 2ist, 1916, near Mayence. 145 THE NEW CAR SLTTONS CONTROL- LING 3QI4B KOfRNG DYNAMO SUPP1YING W1RELE JNSftiiffiGN WiTH- POWER WHAPNEUM/C KiRlBLIN LAMDiKG - RCFELliS MERCEDES MOTOR . GONDOLABMJff ALUMINIUM 1-12 INCHTICK, ' CCWJATED AT SIDES TO GIVE ADDITIONAL STIFFNESS, & SURMOUNTED IY MIS OF WJB6MSED COTTON FABWC SKETCHED UPON AUJMIN1UM GUKRING. FJOPfllElMNING 1,600 THE EARLY CAR. XHHKEW10CII 100(5 IT HflBZflHWBf IKVBTC IT JINKING THI (SOUND WHEN LANDING. Courtesy of the Illustrated London News. COMPARATIVE VIEWS OF THE EARLY AND THE NEW FORWARD CAR OF ZEPPELIN AIRSHIPS. . 146 GERMANY Continued Zorn, Berlin. Builder of a structure airship. Wooden hull frame. Trim controlled by lifting planes and trimming tanks. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes l Zorn (1910) 120 13.8 13,600 210 Experimental airship. Three Ar- gus engines ; three pairs of twin- screws. Three cars. On her trials the airship did not prove satisfac- tory and was eventually dismantled. GREAT BRITAIN "Airships", Ltd., Hendon, N. W. Builders of pressure airships to the Astra and Astra-Torres patents. Armstrong, Whitworth & Co., Ltd., Newcastle-on-Tyne. Builders of Signor E. Forlanini's patents. Trim controlled by lifting planes. pressure airships of the keel-girder type to Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes AW-l (Laid down, 1913) 90 18 15,000 320 . 80 British naval airship. Four en- gines ; twin-screws. AW-2 (Laid down, 1913) 90 18 15,000 320 80 British naval airship. As above. AW-3 (Laid down, 1913) 25,000 1,000 100 British naval airship. Barton (F. A.), London. Builder of a pressure airship of the car-girder type, tanks. Suspension hems stiffened by bamboo strips. Trim controlled by lifting planes and trimming Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes 1 Barton 51.8 12.5 6,440 100 25 Experimental airship, built with the (July, 1905) financial assistance of the War Of- fice. Ballonet : 1,200 me. Two Bu- chet engines, each driving one twin set of propellers consisting of three co-axial screws. Made on July 22, 1905, a partially controlled flight over London (40 km.), but drifted on landing into some trees and was wrecked. barton - "Barton" (1905) 5pencer "Mellin" (I902) 148 GREAT BRITAIN Beedle (W.), London. Builder of a structure airship. Continued Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes i Beedle (1901) 30.5 4.9 500 28 Experimental airship. One auto- mobile engine; twin-screws. (Data and photo wanted.) Bell (Hugh) , London. Builder of a pressure airship of the keel-girder type. Keel of steel tubing, running from end to end. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes i Bell (1848) 17 6.5 Propulsion by manually operated twin-screws. The trials, which took place at Vauxhall Gardens, did not furnish appreciable results. Buchanan (F.) London. Builder of a pressure airship. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes i Buchanan (1902) 30.5 1,260 The trials were not successful. (Photo, or sketch, and additional data wanted.) Gaudron (Auguste), London. Builder of a pressure airship of the girderless type. Trim controlled by ballast. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes l Gaudron (May, 1898) 18.3 8.5 600 2 Experimental airship. One Sie- mens electric motor ; one tractor screw. On her trials the airship made a partially controlled voyage over London, at the conclusion of which she was, however, unable to return against the wind to her starting place and was voluntarily stranded by the pilot. 140 THE NULLI-SECUNDUS (1907) AND THE BABY (1909). GREAT BRITAIN Continued Royal Aircraft Factory (formerly Army Balloon Factory), Farnborough. Builders of pressure airships to various designs. Trim controlled by lifting planes and (on later models) by swivelling screws. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes l Nulli-Secundus (September, 1907) 33.9 9.2 2,400 50 30 Experimental airship, built to the designs of Colonel Capper and S. F. Cody. Keel-girder type; hull of goldbeater's skin. Ballonet: 400 me. One Antoinette engine ; twin- screws. Was badly damaged by a storm on Oct. loth, 1007, near Lon- don, whither the airship had flown from Farnborough. la Dirigible II 36.6 9.2 2,700 100 32 Was re-built and fitted with a bal- (July, 1908) lonet of 500 me. and a second An- toinette engine, but proved unsat- isfactory and was eventually broken up. 2 Baby (May, 1909) 25.6 7.6 600 16 29 British Army airship.- Car-girder type ; inflated fins. Two Buchet en- gines ; one pusher-screw above the car. 2a Beta 31.7 7.6 S45 30 40 Was re-built and fitted with one (June, 1910) Green engine driving twin-screws and with surface fins. Thus al- tered the Beta (ex-Baby) proved a very successful vessel for her size and made trips aggregating 5,000 km. till 1913, when she was dis- mantled. 3 No. 2A (February, 1910) 46 7.6 1,200 80 British Army airship. One Green engine ; twin-screws. Was little successful. 151 r GREAT BRITAIN Royal Aircraft Factory -"Beta" (1910) Royal Aircraft Factory - 'Gamma" (1910) Royal Aircraft Factory - "Delta" (1912") 152 GREAT BRITAIN Continued Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes 4 Gamma 46 9.1 2,265 100 45 British Army airship.* One Green (July, 1910) engine; swivelling twin-screws. Car-girder type. 5 Delta 60 13.4 4,530 200 60 British Army airship.* Car-girder (1912) type. Two Wolseley engines; swiv- elling twin-screws. g Eta 6,000 300 British Army airship.* Car-girder (1913) type. Two Salmson engines ; swiv- elling twin-screws. * In July, 1914, Naval Air Service. the British Army airships were transferred to the (then) newly created Airship Section of the Royal Short Brothers Battersea Park, London, S. W. Builders of airships to various designs. Spencer (C. G. & Sons), London. Builders of airships to various designs. Trim controlled by ballast. Works Name Length Beam Volume Power Speed Nntoa No. Trials (m) (m) (me) (h. P .) (km) i Mellin 23 6.1 560 8 25 Experimental airship. Car-girder, (June, 1902) pressure type. One Siemens elec- tric motor ; one tractor-screw. Made on Sept. ipth, 1902, a partial- ly controlled flight from London to Harrow (32 km.), but lacked pow- er to return, against a moderate wind, to her starting place. 2 Spencer II 28.4 7.3 840 24 Experimental airship of the struc- (No trials) ture type. Aluminum hull ; 8 com- partments. Fabric skin. One An- toinette engine; one tractor screw. Laid down in 1903, was not com- pleted. 153 \GREAT BRITAIN^ Vickers -'H.M.A.N"!" (1911) GREAT BRITAIN Continued Vickers, Sons and Maxim, Ltd., Barrow-in-Furness. Builders of structure airships to their own designs and of girderless pressure airships to the Parseval patents. Trim controlled by lifting planes. (Vickers type.) Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes i No. 1 (Laid down, 1910) 155 14.6 19,890 430 British naval airship. Structure type; 19 gas-cells. Hull-frame of duralumin. Two Wolseley engines mounted in two -cars, the front one driving twin-screws, the' rear one driving one pusher-screw. On Sept. 24th, IQTI, while being towed out of her shed, the airship was blown against the shed and broke in two. She was never repaired. 2 No. 23,000 British naval airship. Structure (Laid down, 1913) type. 3 No. (Laid down, 1913) 84 15.5 12,000 <00 75 British naval airship. Parseval girderless pressure type. 4 No. (Laid down, 1913) 84 15.5 12,000 400 75 British naval airship. As above. 5 No. (Laid chwn. 1913) 84 15.5 12,000 400 75 British naval airship. As above. Willows (E. T.), Cardiff. Builder of pressure airsh'ps of the car-girder and keel-girder types. Trim controlled by swivelling screws. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes l No. 1 (1905) 22.6 5.5 340 7 30 Experimental airship. Car-girder type. One Peugeot engine; one pusher-screw and one pair of twin- * screws (the latter swivelling). No rudder, nor elevator. Notwithstand- ing her small power, this airship handled satisfactorily. 155 Willows -"N91" (1905) 8EP Willows -"N92" (1909) 150 GREAT BRITAIN Continued Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h. P .) Speed (km) Notes 2 No. 2 26.2 6.7 600 30 35 Excursion airship of Mr. Willows. (November, 1909) Keel-girder type. One J. A. P. en- gine ; one pair of swivelling twin- ' screws. Made many trips, includ- ing one from Cardiff to London 2a City-of-Cardiff 36.5 7 910 30 35 (225 km. in 9 hrs.). Was re-built. (1910) Flew on Nov. 4th, 1910, with two on board from London, across the Channel to Douai (io l /2 hrs.). 3 No. 4 30.5 6.1 670 35 55 British naval airship. Keel-girder (October, 1912) type. One Anzani engine ; swivel- ling twin-screws. Built to be car- ried on board ships. 4 No. 5 39.6 7.9 1,400 70 60 Excursion airship of Mr. Willows. (1913) Swivelling twin-screws. ITALY Army Airship Works, Vigna di Valle (Rome). Builders of pressure airships of the keel-girder type to the designs of captains Crocco and Ricaldoni. Trim controlled by lifting planes. Gas-tight compartments. Articulated girder, consisting of a Gall's chain, inserted in the bottom of the hull. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h. P .) Speed (km) Notes i No. 1 63 10 2,750 105 51 Experimental airship. One Cle- (October, 1908) ment-Bayard engine; twin-screws. Ballonet : 500 me. 7 compartments. Fitted with a rigid keel-girder, which was converted into an articu- lated one at the re-construction. la No. 1-bis 60 10.5 3,450 105 52 Ballonet : 650 me. Best endurance : (August, 1909) 300 km. in 7 hrs. Was again re- 1 built. 157 THE WILLOWS CITY OF CARDIFF (1910) AND THE CAR OF THE No. 4 (1912). 158 ITALY Continued Works No. Name Length Trials (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes lb P. 1 60 11.6 4,200 105 52 Ballonet : 800 me. Best endurance : (1910) 470 km. in 14 hrs. Served as an Army training airship until 1914. when she was dismantled. 2 P. 2 (1910) \ 63 11.6 4,400 120 52 Italian Army airships. One Cle- 3 P. 3 (1911) / ment-Bayard engine ; twin-screws. Designed endurance : 10 hrs. Alti- tude : 1,600 m. Ballonet : 900 me. Both airships took a prominent part in Italy's Lybian campaign, be- ing the first airships to see actual war service. The P.2 was disman- tled in 1914. 4 P. 4 (November, I912)\ 63 12 4,700 160 65 Italian Army airships. Ballonet : 5 P. 5 (December, 1912) / 1,200 me. Two F. I. A. T. engines ; twin-screws. Designed endurance : 12 hrs. at 2,000 m. altitude. Best endurance: 460 km. in 9 hrs. (for P.5)- The P. 4 (called also the Citta di lesi) made during the Great War numerous raids on Dalmatia and Istria and was destroyed by Aus- trian seaplanes on Aug. 5th, 1915, while raiding Pola. The P. 5 was destroyed by Austrian seaplanes on Aug. I2th, 1916, in the airship shed of Campalto. 6 M. 1 83 17 12,000 500 70 Italian Army airship. 8 compart- (1912) ments. Armoured car. Two F. I. A. T. engines ; twin-screws. De- signed endurance : 24 hrs. 7 M. 2 83 17 12,100 500 70 Italian naval airship. Improved (Summer, 1913) M.I type. Four Wolseley engines. Best endurance: 1,000 km. in 21 ISO Army Airship Works - "P " Class (I9ICH2) Army Airship Works -'M' Class (1912-16) 1 60 ITALY Continued Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes hrs. Called also the Cittd di Fer- rara. Was shot down by Austrian seaplanes on June 8th, 1915, while homeward bound from a raid on Fiume. 8 M. 3 C3 17 12,100 520 70 Italian Army airships. M.2 type. (October, 1913) I . Four Clement-Bayard engines. 9 M. 4 The M .3 was shot down by Aus- (January, 1914) J trian A. -A. guns on May 4th, 1916. near Gorizia, while homecoming from a raid on Lubiana. 10 V. 1 EO 20 14,650 400 93 Italian naval airship. New type, (February, 1915) built to the designs of Capt. Ver- duzio. Rigid keel-girder of trian- gular trellis-work within the hull. Ballonet: 4,800 me. 12 compart- ments. Two Maybach engines ; twin-screws. Designed endurance : 15 hrs. at full speed and 2,000 m. altitude. 11 M. 5 C3 17 12,100 520 70 Italian Army airship. M.2 type. (April, 1916) 12-13 G. 1 G. 2 20,000 800 80 Italian naval airships. Structure (Laid down 1914) type. Da Schio (Count A'merico), Vicenza (Venetia). Builder of pressure airships of the car-girder type. Particular feature: hull fitted with an elastic underside, doing away with the ballonet. Trim controlled by lifting planes. Works No. Name Trials Length (m) Beam (m) Volume (me) Power Notes i No. 1 Experimental airship of the kite- (1904) balloon type. Was not successful and was converted into a kite-bal- loon during the Russo-Japanese war. (Data wanted.) ' 2 No. 2 35 7.5 1,400 50 22 Experimental airship of the car-gir- (1910) der type. One ballonet. One Maxi- motor engine ; one pusher-screw. Was wrecked by the wind in March, 1911. 3 I (1911) 58 9.4 3,000 72 Japanese Army airship. Car-girder type. Two Koerting engines ; twin- screws. (Information regarding performances wanted.) 4 II /1QI 9\ 58 9.4 3,000 75 Japanese Army airship. As above. \mpany, Akron. Ohio. Builders of airships to various Works No. Name Length Beam Volume Power Speed Triak (m) (m) (me) (kp.) (km) 1 2 OS-IS H.- DH-n 72 XaTr. " " 1/9 THE PASADENA (1913)- 1 80 UNITED STATES Continued Knabenshue (Roy), Pasadena, Cal. Builder of numerous airships of the car-girder, pressure type, all of which served exhibi- tion purposes but one which is listed herewith. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes Pasadena (1913) 45.8 9.2 2,133 39 50 Excursion airship. Designer : Mr. Charles F. Willard. One Hansen engine; twin-screws. Trim con- trolled by lifting planes. The Pas- adena made in 1913 and 1914 nu- merous trips with passengers in California and near Chicago. Knabenshue Aircraft Corporation, New York. Builders of pressure airships. National Airship Company, Berkeley, Cal. Builders, to the designs of Mr. Morrell, of a girderless pressure airship. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h. P .) Speed (km) Notes i Morrell (May, 1908) 157.5 10 12,580 180 ? Six Hansen engines ; six pairs of twin-screws. No ballonet. Six cars. Disastrous trials : the airship lost her shape in mid-air and stranded on a row of houses, kill- ing three and injuring six of the crew. Cost : $40,000. 181 A U. S. NAVY SCOUT AIRSHIP (1917). 182 UNITED STATES Continued Rekar Airship Construction Company, Portland, Ore. Builders of a structure airship. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h.p.) Speed (km) Notes 1 Preble-Rekar 76.3 7.6 4,000 Was not completed. Riggs & Rice, New York. Builders of a pressure airship of the car-girder type. Designer, A. Leo Stevens. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h-p.) Speed (km) Notes l American Eagle (November, 1909) 30.5 7.6 980 35 Experimental airship. One Hansen engine ; twin-screws and one trac- tor-screw. Was not successful, al- though short ascents were made. Toliver Aerial Navigation Company, San Diego, Cal. Builders of a pressure airship of the keelrgirder type. Trim controlled by lifting planes. Works No. Name Trials Length (m) Beam (m) Volume (me) Power (h. P .) Speed (km) Notes 1 Toliver (Laid down 191!) 76.3 12.2 Was not completed. U. S. Army & Navy Joint Board, Washington, D. C. The construction of an experimental structure airship, called the DR-l , has been decided upon in 1917. TOP THE MORRELL (1908); BOTTOM THE AMERICAN EAGLE (190. 184 II. THE WORLD'S AIRSHIP PRODUCTION 185 II. THE WORLD'S AIRSHIP PRODUCTION (VOLUME IN CUBIC METERS) Country 1901 1902 1903 1904 1905 Belgium Brazil 3,900 5,230 7,464 3,440 2,100 3,400 10,400 500 1,820 840 6,440 Itnlv 1,200 , Total -. - 5,730 9,284 8,180 2,100 21,440 1 86 II. THE WORLD'S AIRSHIP PRODUCTION (VOLUME IN CUBIC METERS) -Continued Country. 1906 1907 1908 1909 1910 3 150 4 goo 2 700 Brazil 3,930 10,700 7 540 21 950 43 155 13,730 16 600 39 500 25 720 50 350 Great Britain 2,400 1,200 5 140 Italy 2 750 5 065 8 780 Japan 1 400 Russia 1,800 5,570 Spain 960 United States 14 540 6 010 Total 17,660 30 660 66 130 65 795 118 195 187 II. THE WORLD'S AIRSHIP PRODUCTION Continued (VOLUME IN CUBIC METERS) Country 1911 1912 1913 1914 1915 11,750 2,750 * * * Rrn7il * 37,005 24,850 41,400 * * 125,210 104,265 230,000 594,000** 1,031,000** Great Britain 25,530 1,400 * * Italy 4,400 21,400 38,800 * * 3,000 3,000 * * 8,780 2,150 * * United States 9,800 2,130 Total 190,145 193,745 313,730 1 No reliable information available. 1 Approximate estimate, based on the productive capacity of the Schutte-Lanz and Zeppelin factories only. 188 II. THE WORLD'S AIRSHIP PRODUCTION Continued (VOLUME IN CUBIC METERS) Country 1916 1917 1918 1919 1920 * * Brazil * * 1,329,000** Great Britain * Italy * * Russia * * United States * No reliable information available. ** Approximate estimate, based on the productive capacity of the Schutte-Lanz and Zeppelin factories only. i8g III. THE MILITARY AIRSHIP FLEETS 191 III. THE MILITARY AIRSHIP FLEETS * On August 1st, 1914 BELGIUM 2 SCHOOL AIRSHIPS La Belgique (1909-14), 5 tons; 120 h.p.; 52 km Vivinus. Zodiac (1910-14), 2 tons; 50 h.p.; 40 km. Zodiac. FRANCE 7 FIRST CLASS AIRSHIPS Tissandier (bldg.), 31 tons; 1,300 h.p.; 80 km. Lebaudy. 27 tons: li000 h>p - : ^ km -- Astra - /MJN 23 tons; 1,400 h.p.; 85 km. Clement-Bayard. (bldg.)J vii (bid!')} 25 tons: 1>00 h - p>: m km -- Zodiac - 6 SECOND CLASS AIRSHIPS VIII (bldg.), 19 tons; 1,200 h.p.; 80 km. Army Works. Spiess (1913), 18 tons; 400 h.p.; 70 km. Zodiac. Commandant-Coutelle (1913), 11 tons; 400 h.p.; 62 km. Zodiac. Dupuy-de-L6me (1912), 10 tons; 260 h.p.; 55 km. Clement-Bayard. Adjudant-Vincenot (191 1-13), 10 tons; 260 h.p.; 56 km. Clement-Bayard. Lieut. Selle-de-Beauchamp (1910), 1 1 tons; 200 h.p.; 45 km Lebaudy. * The airships herewith listed are divided into vessels of first class, corresponding to the French cruiser class and to the Italian grande (large) class; second class, corresponding to the French eclaireur (scout) class and to the Italian medium class; and third class, corresponding to the French vedette class and to the Italian piccolo (small) class. 192 III. THE MILITARY AIRSHIP FLEETS Continued 4 THIRD CLASS AIRSHIPS E. Montgolfier (1913), 7 tons; 160 h.p.; 69 km. Clement-Bayard. Fleurus (1912), 8 tons; 160 h.p.; 60 km. Army Works. Capitaine-Ferber (191 1), 7 tons; 220 h.p.; 56 km. Zodiac. Capitaine-Marchal (1910), 8 tons; 160 h.p; 45 km. Lebaudy. GERMANY 15 FIRST CLASS AIRSHIPS L. 4, L. 7 (bldg.), 33 tons; 1,080 h.p.; 80 km. Schutte-Lanz. L. 3 (1914), L. 5, L. 6 (bldg.); 30 tons; 800 h.p.; 85 km.-Zeppelin. S. L. II (1914), 25 tons; 720 h.p.; 87 km.-Schutte-Lanz. Z. VII (1913), Z. VIII, Z. IX, Z. X (bldg.); 24 tons; 600 h.p.; 80 km.-Zeppelin. Z. IV, Z. V, Z. VI (1913). 22 tons; 540 h.p.; 77 km.-Zeppelin. Z. Ill (1912), Z. II (1910-1 1). 20 tons; 450 h.p.; 76 km.-Zeppelin. 4 SECOND CLASS AIRSHIPS P. V (1914), 13 tons; 400 h.p.; 75 km.-Parseval. M. IV (1913), 14 tons; 450 h.p.; 75 km. Army Works. P. IV (1913), 1 1 tons; 360 h.p.; 71 km.-Parseval. P. Ill (191 1), 1 1 tons; 400 h.p.; 65 km.-Parseval. 2 THIRD CLASS AIRSHIPS P. II (1910), 9 tons; 360 h.p.; 51 km.-Parseval. M. I (1912). 7 tons; 150 h.p.; 45 km.-Army Works. 103 III. THE MILITARY AIRSHIP FLEETS Continued GREAT BRITAIN 2 FIRST CLASS AIRSHIPS No. 15 (bldg.). 27 tons. Armstrong. No. ? (bldg.), 25 tons; 1,500 h.p. Vickers & Maxim. 9 SECOND CLASS AIRSHIPS Three of 13 tons; 200 h.p.; 72 km.; building. Armstrong-Forlanini. Three of 13 tons; 360 h.p.; 75-80 km; building. Vickers-Parseval. No. 3 (1913) and one building; 10 tons; 400 h.p.; 82 km Astra. No. 2 (1913), 1 1 tons, 360 h.p.; 68 km. Parseval. 4 SCHOOL AIRSHIPS Delta (1912), Eta (1913); 5 tons; 200 h.p.; 45 km. R. Aircraft Factory. Gamma (1910); 2 tons; 100 h.p.; 45 km. R. Aircraft Factory. Willows ( 1 9 1 2) ; 1 ton ; 35 h.p. ; 45 km. Willows. ITALY 3 FIRST CLASS AIRSHIPS G. 1-G. 2 (bldg.). 22 tons; 800 h.p.; 80 km. Army Works. One, unnamed, building, 27 tons; 1,000 h. p.; 100 km. Forlanini. 6 SECOND CLASS AIRSHIPS V. 1 (bldg.), 16 tons; 400 h.p.; 90 km. Army Works. M. 5, M. 4 (bldg.), M. 3, M. 2 (1913), M. 1 (1912); 13 tons. 500 h.p.; 70 km. Army Works. 194 III. THE MILITARY AIRSHIP FLEETS Continued 2 THIRD CLASS AIRSHIPS P. 4 (1912), P. 5 (1913), 5 tons; 160 h.p.; 62-65 km. Army Works. JAPAN 1 SECOND CLASS AIRSHIP Yuhi (1912); 10 tons; 300 h.p.; 66 km. Parseval. RUSSIA 3 FIRST CLASS AIRSHIPS Three 25 ton, 1,000 h.p. airships building at Astra, Clement-Bayard and Zodiac respectively. 6 SECOND CLASS AIRSHIPS Albatros (1914), 10 tons; 300 h.p.; 61 km. Ijora. "B" (1913), 1 1 tons; 400 h.p.; 63 km. Astra. "C" (1913), 11 tons; 360 h.p.; 67 km. Parseval. "D" (1913), 10 tons; 360 h.p.; 55 km Clement-Bayard. Two building, at Ijora and Russo-Baltic, respectiv ly. 2 THIRD CLASS AIRSHIPS Kretchet (191 1), 6 tons, 200 h. p.; 50 km. Army Works. Griff (1910), 8 tons, 220 h.p.; 59 km. Parseval. 6 SCHOOL AIRSHIPS Bercout, Korchoune, Kobtchik, Sokol, Tchaika, Yastreb (1909-12), 2-4 tons, 60-105 h.p.; 47 54 km. TURKEY 1 SCHOOL AIRSHIP No. 1 (1910-13), 2 tons; 50 h.p.; 40 km. Parseval. 195 SCALE-DRAWN SILHOUETTES OF THE PRINCIPAL GERMAN AIRSHIP TYPES ZEPPELIN SCHUTTE-LANZ PARSEVAL 196 IV. COMPARATIVE STRENGTH OF THE MILITARY AIRSHIP FLEETS 197 IV. COMPARATIVE STRENGTH OF THE MILITARY AIRSHIP FLEETS On August 1st, 1914 Germany 13 airships of 237 tons, commissioned. 8 airships of 21 1 tons, building. France 9 airships of 90 tons, commissioned. 8 airships of 200 tons, building. Russia 12 airships of 74 tons, commissioned. 5 airships of 95 tons, building. Italy 5 airships of 49 tons, commissioned. 6 airships of 1 1 3 tons, building. Great Britain 6 airships of 34 tons, commissioned. 9 airships of 140 tons, building. Japan 1 airship of 1 tons, commissioned. No airship building. United States No airship commissioned No airship building. V. AIRSHIP LOSSES OF THE ALLIES 199 V. AIRSHIP LOSSES OF THE ALLIES August 1st, 1914 June 1st, 1917 (Compiled from Official Data) FRANCE No. Name Date Place Cause of Loss i D. .. Sept., '14 France Accident. 2 Alsace ID-VIS Rethel, France Shot down by German guns. 3 T. .. 5-13-M6 Porto Torres, Italy Caught fire and blew up, killing the crew of six. 4 2-25-M7 Sarreguemines, Lorraine Shot down by German guns. GREAT BRITAIN No. Name Date Place Cause of Loss i 2 7-28-' 15 4-21-17 Wormwood Scrubs, England Strait of Dover Blew up in shed during inflation. Shot down by German seaplane. ITALY No. Name Date Place Cause of Loss i 2 3 4 M. 2 P. 4 M. 3 P. 5 6-8-M5 8-5-15 5-4-16 8-12-16 Fiume, Hungary Pola, Austria Gorizia, Italy Campalto, Italy Shot down by Austrian seaplane. Shot down by Austrian seaplane. Caught fire and blew up, killing the crew of four. Destroyed in shed by Austrian seaplanes. RUSSIA No. Name Date Place Cause of Loss l Apr. 27, '17 Stanislawow, Galicia Shot down by Crew saved. Austrian guns ; fell in Russian lines. 200 VI. GERMANY'S AIRSHIP LOSSES 201 VI. GERMANY'S AIRSHIP LOSSES (August 1st, 1914 July 1st, 1917) OFFICIAL LIST The following list includes only airships: (1) officially claimed by the Allies as having been captured or destroyed by their forces and (2) officially acknowledged by Germany as having been lost. No. Name Date Place Cause of Loss 1 Z. VIII Aug. 22. 1914 Badonviller, France Shot down by French artillery; 4 of crew taken pris- oner. 2 ? Sept 6, 1914 Seradz, Russia Captured on her moorings by a troop of Cossacks. Crew taken prisoner. 3 Z. V Sept. 28, 1914 Warsaw, Russia Shot down by Russian artillery. Crew of IS taken prisoner. 4 P. V Jan. 1, 1915 Libava, Russia Shot down by Russian artillery. Crew of 7 taken prisoner. 5 L. 3 Feb. 17, 1915 Fano Island, Denmark Stranded and broke up. Crew of 16 were interned. 6 L. 4 Feb. 17, 1915 Esbjerg, Denmark Foundered off the coast. Four of the crew were lost. 12 were interned. 7 L. 8 March 5, 1915 Tirlemont, Belgium Broke up on landing by night. 8 LZ.37 June 9, 1915 Ghent, Belgium Destroyed in mid-air bv British aeroplane. Crew killed in fall. 9 L. ? Aug. 10, 1915 Ostende, Belgium Destroyed by British seaplanes while berthing. 10 Z. ? Aug. 24, 1915 Vilna, Russia Shot down by Russian artillery. Crew of 10 taken prisoner. 11 Z. ? Dec. 5, 1915 Kalkun, Russia Shot down by Russian artillery. Crew killed in fall. 12 L. 19 Feb. 2,1916 North Sea Damaged by artillery, while raiding England. Foun- dered with crew of 16. 13 LZ. 77 Feb. 21, 1916 Revigny, France Shot down by French artillery. Crew of 15 killed in fall. 14 L. 15 Apr. 1,1916 Kentish Knock, England Shot down by British aeroplane. Seventeen of crew taken prisoner; i killed in fall. 15 L. 20 May 3, 1916 Stavanger, Norway Stranded and broke up. Sixteen of crew interned ; ; killed in fall. 202 VI. GERMANY'S AIRSHIP LOSSES Continued No. Name Date Place Cause of Loss 16 17 L. 7 LZ. 85 May 4, 1916 May 5, 1916 Schleswig Coast, Germany Salonica, Greece Shot down by British warships. Seven of crew taken prisoner. Shot down by Allied warships. Crew of 14 taken pris- oner. 18 L. 21 Sept. 3, 1916 Cuffley, England Shot down by British aeroplane. Crew of 18 killed in fall. 19 L. 32 Sept. 24, 1916 Essex County, England Shot down by British aeroplane. Crew of 22 killed in fall. 20 21 L. 33 L. 31 Sept. 24, 1916 Oct. 1, 1916 Essex County, England Potter's Bar, England Shot down by British aeroplane. Crew of 22 taken, prisoner. Shot down by British aeroplane. Crew of 19 killed in fall. 22 23 24 L. ? L. ? L. 39 Nov. 27, 1916 Nov. 28, 1916 M'ch 17, 1917 Off Durham Coast, England Norfolk Coast, England Compiegne. France Shot down by British aeroplanes. Crew killed in fall. Shot down by British aeroplanes. Crew killed in fall. Shot down by French artillery. Crew of 19 killed in fall. 25 26 27 L. 22 L. 43 Z. 48 May 14, 1917 June 14,1917 June 17,1917 North Sea North Sea East Coast of England Shot down by British seaplane. Crew killed in fall. Shot down by British warships. Crew killed in fall. Shot down by British aeroplane. Five of the crew were taken prisoner ; the remainder were killed in the fall. SUPPLEMENTARY LIST The following list includes airships semi-officially or privately reported to have been destroyed by Allied forces or to have been otherwise lost. No official confirmation of these losses is presently available, but the sources of information appear on the main as fairly reliable. No. Name Date Place Cause of Loss l Z. ? Aug. 6, 1914 Metz, Germany Bombed in shed by French aeroplane. 2 Z. ? Oct. 10, 1914 Diisseldorf, Germany Bombed in shed by British aeroplanes. 3 LZ. 31 Nov. 21, 1914 Friedrichshafen, Germany Bombed in shed by British aeroplanes. 4 P. ? Dec. 24, 1914 Brussels, Belgium Bombed in shed by British aeroplane. 5 P. ? Dec. 25, 1914 Cuxhaven, Germany Bombed in shed by British seaplanes. 6 ? Jan. 23. 1915 North Sea Foundered during a storm. 7 ? Feb. 26, 1915 Pola, Austria Foundered during a storm. 203 VI. GERMANY'S AIRSHIP LOSSES Continued No. Name Date Place Cause of Loss 8 1 M'ch 5, 1915 Cologne, Germany Broke up on landing in a storm. 9 ? M'ch 5, 1915 Off Calais, France Lost with all on board. 10 Z. ? Apr. 12, 1915 Thielt, Belgium Broke up on landing. Eleven of crew killed. 11 ? Apr. 26, 1915 Gontrode, Belgium Bombed in shed by French aeroplanes. 12 ? May 13, 1915 Gierlesche, Belgium Broke up on stranding in a wood. 13 ? May 21, 1915 Kdnigsberg, Prussia Broke away, unmanned. Foundered off Heligoland. 14 LZ. June 7, 1915 Evere, Belgium Bombed in shed by British aeroplanes. 15 P. ? June 16, 1915 Adamello, Austria Broke up on stranding against a mountain. Crew killed. 16 ? Aug. 17, 1915 North Sea Foundered on returning from a raid on England. 17 ? Sept. 8, 1915 Brussels, Belgium Broke up on berthing during a storm. Four of crew killed. 18 ? Oct. 13, 1915 Saint-Hubert, Belgium Blew up in mid-air. Crew killed in fall. 19 L. 18 Nov. 17, 1915 Tondern, Germany Blew up in shed, having accidentally been set on fire. 20 ? Nov.. 1915 Grodno, Russia Damaged by Russian artillery; broke up on landing. 21 Z. 28 Nov.. 1915 Hamburg, Germany' Foundered during a storm. 22 P. ? Nov., 1915 Bitterfeld, Germany Broke up on landing. 23 ? Jan. 30. 1916 Mainvault, Belgium Damaged by French aeroplane over Paris; broke up on landing. 24 ? Apr. 26, 1916 Bruges, Belgium Bombed in mid-air by French aeroplane. 25 ? May 10, 1916 Veles, Serbia Broke up on landing during a storm. 26 ? July 20, 1916 Tukkum, Russia Damaged by Russian artillery, over Riga; broke up on landing. 27 ? Sept. 3, 1916 Off Sylt, Germany Damaged by British artillery while raiding London ; foundered. 28 ? Sept. 22, 1916 Rheinau, Germany Bombed in shed by French aeroplanes. 29 ? Nov. 21, 1916 Mayence. Germany Wrecked by a storm. Twenty-seven of the crew were killed, i was saved. 30 ? Dec. 28, 1916 Tondern, Germany 1 31 ? Dec. 28, 1916 Tondern, Germany > Collided, while berthing. 32 ? Apr. 1, 1917 Odobesci, Roumania Bombed by Russian aeroplanes. 33 ? Apr. 21. 1917 Duisburg, Germany Wrecked by a storm. Entire crew killed. 204 VII. THE GERMAN AIRSHIP RAIDS ON GREAT BRITAIN 205 VII. THE GERMAN AIRSHIP RAIDS ON GREAT BRITAIN (List closed on July 1st, 1917) 1915 Date Raid On Killed Injured Jan. 19 Yarmouth and District 4 Apr. 14 Tyneside Apr. 15 Lowestoft and East Coast Apr. 29 Ipswich and Bury St. Edmunds May 10 Southend 1 May 16 Ramsgate 2 May 27 Southend : 3 May 31 Outer London 6 June 4 East and Southeast Coasts 24 June 6 East Coast. Zeppelin LZ. 38 destroyed on return trip near Ghent 5 June 15 North-East Coast 16 Aug. 9 East Coast. Zeppelin L. 10 destroyed on return trip off Ostende 15 Aug. 12 East Coast .-.. 6 Aug. 17 Eastern Counties 10 Sept. 7 Eastern Counties 17 Sept. 8 Eastern Counties and London District 20 Sept. 11 East Coast Sept. 12 East Coast Sept. 13 East Coast Oct. 13 London Area and Eastern Counties 56* * 1 5 soldiers. f 1 3 soldiers. Total. 1 8 2 3 40 40 40 14 23 36 43 86 114f 459 Date 1916 Raid On Killed Injured Jan. 31 M'ch 5 M'ch 31 Norfolk, Suffolk, Lincolnshire, Leicestershire, Staffordshire and Derbyshire. Zeppelin L. 1 9, dam aged by defense, foundered on return trip in the North Sea Yorkshire, Lincolnshire, Rutland, Huntingdon, Cambridgeshire, Norfolk, Essex, and Kent Eastern Counties and North-East Coast. 67 18 43 101 52 66 206 VII. THE GERMAN AIRSHIP RAIDS ON GREAT BRITAIN Continued 1916 Date Raid On Apr. 1 North-East Coast Zeppelin L. 15 brought down in Thames 16 Apr. 2 South-Eastern Counties of Scotland 10 Apr. 4 East Coast Apr. 5 North-East Coast 1 Apr. 24 Norfolk and Suffolk Apr. 25 Essex and Kent Apr. 26 East Kent Coast May 2 North-East Coast of England and South-East Coast of Scotland 9 July 29 Lincolnshire and Norfolk July 31 Southeastern and Eastern Counties Aug. 3 Eastern and Southeastern Counties Aug. 9 East and North-East Coast 8 Aug. 24 Northeastern Coast Aug. 25 Southeastern Coast and London Area . . . . 8 Sept. 2-3 Eastern Counties and London by large number of airships. Schiitte-Lanz L. 21 brought down at Cuffley 2 Sept. 23-24 Lincolnshire, Eastern Counties and London by 14 or 15 airships. Zeppelin L. 32 destroyed, L. 33 captured in Essex 38 Sept. 25-26 East and North Coasts 36 Oct. 1-2 East Coast and London District by 10 airships. Zeppelin L. 31 brought down at Potters Bar. . 1 Nov. 27-28 Northeastern and Norfolk Coast. One Zeppelin destroyed a mile off Durham coast, and anothe- nine miles off Norfolk coast 4 241 Total for 1915 and 1916. . 426 Killed Injured 100 11 8 1 27 17 36 11 125 37 1 37 620 1,079 1917 Date Raid On Killed Injured M'ch. 16-17 ! S. E. Coast and London Area. Zeppelin L. 39 brought down on return trip, near Compiegne by French gunners May 23-24 Eastern counties by 5 airships June 16-17 Kent and East Anglia by 2 airships. Zeppelin Z. 43 destroyed on the East Caast 16 207 THE END OF A RAIDER. 208 VIII. THE COMMERCIAL AIRSHIP FLEETS OF 1914 209 THE SCHWA BEN OF THE DELAG LINE, AND HER ACCOMMODATIONS. 2IO VIII. THE COMMERCIAL AIRSHIP FLEETS OF 1914 FRANCE Compagnie G^nerale Transae"rienne, Paris. Established in March, 1909, for the commercial exploitation of Astra airships. Fleet: V ilk-de-Nancy (1909), 4 tons, and ViUe-de-Pau (1910), 5 tons. Both dismantled. One 10 ton airship ordered in 1913. No balance sheet available. GERMANY "Delag" Line (Deutsche Luftschiffahrt Aktien-Gesellschaft), Frankfort-on-the-Main. Established in November, 1909, for the commercial exploitation of Zeppelin airships. Fleet: Deulsch'and (1910), 21 tons; LZ. 6 (1908) 18 tons; flcufacA- land-II (1911), 21 tons; Schwaben (1911), 20 tons; all lost. Viktoria-Luise (1912), Hansa (1912), Sachsen (1913), all of 21 tons. The three latter were chartered in 1914 by the German Navy and placed in commission as training airships BALANCE SHEET, 1910-13 Year 1910 1911 1912 1913 Nu ' h' sioned 20) 2( 2 ) 3( s ) SCO 39 41 62 63 690 810 1,080 1,530 35 136 302 353 41 158 392 737 4,167 20,330 52,924 63,363 33 h. 41 m. 360 h. 38 m. 932 h. 9 m. 1,169 h. 42 m. 868 3,263 8,299 14,010 2(') K 5 ) 1( 6 ) Passengers injured " (!) Deutschland and LZ. 6. ( 2 ) Deutschland II and Schwaben. (") Schwaben, V i\loria-Luise and Hansa. (') Vil^loria-Luise, Hansa and Sachsen. ( 5 ) Deulschland II. ( 6 ) Schwaben. 211 IX. THE WORLD'S AIRSHIP SHEDS 213 MODEL OF A GERMAN AIRSHIP SHED WITH DISAPPEARING ROOF. 214 IX. THE WORLD'S AIRSHIP SHEDS Dimensions are given in metres (m). In the column "Type": Dem. = demountable; Sta. = stationary; Rev. = revolving; Flo. = floating. AUSTRIA Place Owner Length (m) Width (m) Height (m) Type Year 70 20 18 Sta. 1911 70 20 18 1909 Cl 70 20 18 ( 1911 M 120 25 20 N 1913 Innsbruck . .... . . 1914 1914 Prague (or Praha) 1914 1914 100 M 1913 BELGIUM Place Owner Length (m) Width (m) Height (m) Type Year Wilryck (Antwerp) 90 18 20 Sta. 1911 u M 70 20 20 fi 1912 (Note. During the German "occupation of Belgium a large number of airship sheds have been erected, particularly at Brussels, Evere, Ghent, Liege, Namur, Ostende and Wavre, most of which are over 1 50 m. long and of permanent character. The sheds of Wilryck have, furthermore, been lengthened.) r AIRSHIP SHED AT LA MOTTE-BREUIL (FRANCE). 216 IX. THE WORLD'S AIRSHIP SHEDS Continued FRANCE Place Owner Length (m) Width (m) Height (m) Type Year Army 70 Sta. 1909 Belfort 100 1911 tt 100 1911 ii 100 1912 tt 100 1912 130 Sta. 1906-13 140 tt 1906-13 Chalons-sur-Marne 70 tt 1909 M 100 tt 1909 M 70 Dem. 1909 tt 70 tt 1909 tt 70 tt 1909 100 Sta. 1912 Astra 90 20 20 ' tt 1908 M Clement-Bayard 70 20 18 tt 1909 La Motte-Breuil tt tt 80 20 18 tt 1909 tt tt tt 1914 Army 80 tt 1912 Moisson Lebaudy 70 tt 1900 n M 60 tt 1905 tt Army 130 38- 30 tt 1911 Nancy . . 70 tt 1908 Pau Astra 80 tt 1910 Reims Army 100 Sta. 1911 tt tt 100 tt 1911 tt tt 130 3Q 20 Rev. 1914 Astra 90 20 20 Sta. 1906 60 tt 1911 tt tt 160 25 24 tt 1913 Toul Army 100 tt 1912 tt 100 tt 1911 tt tt 100 tt 1911 217 AIRSHIP SHED AT MANNHEIM (GERMANY). 218 IX. THE WORLD'S AIRSHIP SHEDS Continued GERMANY Place Owner Length On) Width (m) Height (m) Type Year Aix-la-Chapelle (Aachen) 150 Rev 1914 Allenstein 150 1914 Baden-Oos Delag Line 158 25 25 Sta 1910 Berlin-Biesdorf 135 25 25 Rev 1909 Berlin-Juntjf ernheide 150 50 30 Sta 1913 Berlin- Johannistal City 82 25 25 1908 M " y 163 45 28 5 1911 Berlin-Tegel 50 18 20 1905 it 70 22 1907 ii 14 101 25 25 1910 Bitterfeld L F G 75 25 25 1908 <( H 100 33 25 1909 Braunschweig . Citv 180 35 28 1914 Bremen 140 40 25 1913 Breslau 150 40 25 1913 Cannstadt 150 40 25 1914 Carlsruhe H 150 40 25 Cologne Koln -Bickendorf 150 50 27 5 1909 Cologne-Nippes Clouth 40 16 12 5 1909 Cuxhaven 180 75 30 Rev 1913 Darmstadt 150 50 30 ii 1914 Dresden City 191 6 58 33 Sta 1914 Diisseldorf ti 152 25 24 ii 1910 Emden 150 25 25 Rev 1914 Frankfort-on-the-Main . . 160 30 24 Sta 1911 Friedrichshafen 180 46 20 tt 1908 tt 250 1915 Gotha City 176 26 26 tt 1910' Graudenz 150 Rev 1914 Hannover Citv 150 25 25 1914 Hamburg-Fuhlsbiittel 80 35 25 Sta 1911 tt Citv 165 51 32 ti 1911 Helgoland 180 60 30 1914 tt ft tt . 1915 Kiel Private 170 30 25 Sta 1910 Konigsberg 170 42 38 tt 1911 Lahr tt 150 40 25 Rev 1914 Leichlingen Private 80 23 24 Sta. 1909 2ig AIRSHIP SHED AT FRANKFORT-ON-THE-MAIN (GERMANY) 22O IX. THE WORLD'S AIRSHIP SHEDS Continued Place Owner Length (m) Width (m) Height (m) Type Year Leipzig-Lindental 120 25 20 St-i Leipzig-Mockau City 194 69 32 5 tt Liegnitz 150 50 30 it 150 28 95 tt ii Mayence (Mainz) . City Metz Army 150 28 25 Sta a 150 28 25 tt Munich 80 25 25 tt n Posen . . . n 150 Potsdam 175 50 35 tt M tt tt Putzig tt Schneidemuhl ....'. 150 tt Strasbourg tt 150 28 25 Cltn Stuttgart City 150 Thorn 150 40 M Tondern. . . 180 60 Poir 180 60 (( it it Treves (Trier) / . . Army 176 40 35 ^ti Wanne Private 100 32 OQ if Wilhelmshaven Navy 180 Rev. 1915 GREAT BRITAIN Place Owner Length (m) Width (m) Height (m) Type Year Barrow-in-Furness 164 45 00 c*- Brighton 60 Farnborousrh tt 60 tt 1911 11 tt 90 tt tt 115 tt Hoo-on-Medway 164 45 00 Kingsnorth 164 M 00 Wormwood Scrubbs . Private 100 tt 1914 M 60 1910 221 REVOLVING SHED AT BERLIN-BIESDORF (GERMANY). 222 IX. THE WORLD'S AIRSHIP SHEDS Continued HOLLAND Place Owner Length (m) Width (m) Height (m) Type Year Soesterberg (Utrecht) Army 60 Sta. 1911 ITALY Place Owner Length (m) Width (m) Height (m) Type Year Alessandria Army 68 30 23.6 Sta. 1913 Baggio (Milan) it 92 36 27 1911 it 91 30 24 1910 Bovisa (Milan) Usuelli 90 1911 84 18 21 1909 Navy 110 24 32 1911 Ferrara Army 110 24 32 1911 lesi Navy 110 24 32 1913 Mapre (Vicenza) ... ... 1913 103 41 35 1909 Schio Da Schio 1909 Tripoli (Lybia) 100 25 25 1911 Vigna di Valle (Rome) tt 71 14 20.6 1907 M it 71 14 20.6 1908 M tt 90 22 25.6 1911 JAPAN Place Owner Length (m) Width (m) Height (m) Type Year Makano 80 25 20 Sta. 1910 80 20 18 it 1910 Tokorozawa 100 25 22 it 1911 n tt 130 30 25 tt 1912 223 AIRSHIP SHED AT BARROW-IN-FURNESS (GREAT BRITAIN). 224 IX. THE WORLD'S AIRSHIP SHEDS Continued RUSSIA Place Berditcheff Brest-Litovsk . . it n Dvinsk Homel. Kieff Kovno Libava Lutsk Minsk Moscow Petrograd 14 tt Reval 7 ... Riga u Salisi-Gatchina . u Sebastopol Sveaborg Vitebsk Vladivostok Warsaw. . Owner Army Length (m) 70 166 80 80 166 166 70 70 100 80 80 80 80 50 166 70 80 70 Width (m) 20 48 48 48 20 20 25 48 Height (m) Type Year Sta. 25 1911 1914 1908 1908 1914 1914 1911 1911 1912 1914 1909 1911 225 THE SHED OF THE PASADENA AT PASADENA, CAL. 226 IX. THE WORLD'S AIRSHIP SHEDS Continued SPAIN Place Owner Length (m) Width (m) Height (m) Type Year Guadalajara Army M 80 15 20 Sta. H 1908 1914 M SWITZERLAND Place Owner Length (m) Width (m) Height (m) Type Year Astra Co. 90 Sta. 1910 TURKEY Place Owner Length (m) Width (m) Height (m) Type Year San Stefano Army M 52 150 15 18 Sta. (4 1913 1915 M UNITED STATES Place Owner Length (m) Width (m) Height (m) Type Year Fort Omaha, Neb Army 60 Sta. 1908 Navy Flo. 1915 227 THE U. S. NAVY FLOATING SHED AT PENSACOLA, FLA. 228 INDEX OF THE WORLD'S AIRSHIPS NOTE. The letter, or group of letters, bracketed after each airship's name indicates the latter's registry, regardless of the builder's nationality or of the country in which the airship was built. "The registry of an aircraft is determined by the nationality of its owner." (Code of the Air, Article III.) ABBREVIATIONS. B, Belgium; BR, Brazil; D, Germany; DM, Denmark; E, Spain; F, France; GB, Great Britain; I, Italy; J, Japan; ML, Netherlands; OE, Aus- tria; R, Russia; T, Turkey; US, United State- A Adjudant-Reau (P), 21, 66, 67, 68. Adjudant-Vincenot (F), 72, 73, 74. Akron (US), 177, 178. Albatros (R), 171. Alfonso XIII (E), 173. Alsace (F), 200. America (US), 79, 80. American Eagle (US), 183, 184. Astra-Torres I (F), 27, 64, 65, 66, 68. Ausonia (I), 164, 165. Austria (OE), 54, 57. B Baby (GB), 150, 151. Baldwin-6, -9 (US), 175. Bartholomeo-de-Gusmao (BR), 95. Barton (GB), 147, 148. Baumgartner (D), 103. Beedle (GB), 149. Bell (GB), 149. Berkout (R), 63. Beta (GB), 151, 152. Boemches (OE), 53. Bradsky (D), 71, 76. Buchanan (GB), 149. Capitaine-Ferber (F), 98, 101. Capitaine-Marchal (F), 82, 84, 86, 87. Castor-et-Pollux (F), 88, 89. Charlotte (D), 106, in. Citta di Ferrara (I), 159. Citta di lesi (I), 159. Citta di Milanp (I), 162, 163. Citta di Venezia (I), no, 113. City-of-Cardiff (GB), 157, 158. Clement-Bayard I (F), 63, 71. Clement-Bayard II (GB), 71, 72. Clouth (D), 104, 105. Colonel-Renard (F), 63, 68. Commandant-Coutelle (F\ 98, 101. Conte (F), 66, 67. D Davis (US), 99. Debayeux (F), 75. Delta (GB), 152, 153. De Margay (F), 75. Deutschland (D), 127, 131. Deutschland II (D), 131. Dirigible II (GB), 151. DN-i (US), 176, 177. DN-2, DN-3 (US), 38, 177. DN-4 DN-6 (US), 175. DN-7 DN-is (US), 179, 182. DN-i6, DN-I7 (US), 179. Dorhofer (D), 107. DR-i (US), 183. Duindigt (NL), 98, 99. Dupuy-de-L6me (F), 24, 72, 73, 76, 77. 229 E. Montgolfier (F), 72, 73. Espana (E), 65. Estaric (OE), 55. Eta (GB), 153. Eubriot (F), 77. F. i, F. 2 (R), 170, 171. F. 3, F. 5, F. 6 (I), 165. Faure (F), 95. Fionia (DM), 59. Fleurus (F), 58, 60, 61. G. i, G. 2 (I), 161. Gamma (GB), 152, 153. Gaudron (GB), 149. General-Meusnier (E), 61. Giffard No. i, No. 2 (F), 78, 79. Goloub (R), 170, 171. Griff (R), 29, 108, no, in. H H. i (D), 175- Haemein (D), 52, 53. Hansa (D), 133. Italia I, II (I), 161, 163, 164. Kiel I (D), 125. Kobtchik (R), 171. Korchoune (R), 101. Kretchet (R), 85, 169. L. i (D), 133, 136. L. 2 (D), 135- 138- L. 3 (D), 137- L. 4 (D), 121. L. 5 (D), 139- L. 6 (D), 139- L. 7 (D), 121. L. 8 L. 10 (D), 139. L. ii L. 19 (D), 140, 141. L. 20 (D), 141, 142, 143. L. 21 (D), 121. L. 22 L. 29 (D), 141. L. 30 L. 40 (D), 143. L. 43 (D), 203. La Belgique (B), 56, 57. La France (F), 58, 59. L. A. G. I, II (D), 115. L'Aigle (F), 87. Lebaudy-I, -II, -III, -IV (F), 81, 82, 83. Lebedj (R), 85. Le Compagnon, (F), 89. Leichlingen (D), 116, 117. Leonardo da Vinci (I), 162, 163. Le Temps (F), 98, 101. Liberte (F), 82, 85. Lieutenant-Chaure (F), 65. Lieutenant-Selle-de-Beauchamp (F), 87. LZ. 4 (D), 129, 130. LZ. 5 (D), 129, 132. LZ. 6 (D), 129, 134. LZ. 77 (D). 137- LZ. 85 (D), 139. M M. I (D), 114, 115. M. II (D), 115. M. Ill (D), 114, 117. M. IV (D), 114, 117. M. I, M. II (OE), 55. M. Ill (OE), 31, 52, 53- M. i (I), 159, 160. M. 2 (I), 159, 160. M. 3 (I), 160, 161. M. 4 (I), 160, 161. M. 5 (I), 160, 161. M-a (D), 115. Malecot (F), 88, 95. 230 Mayfly (GB), 45, 154, 155. Mediterraneen-II (F), 75. Mellin (GB), 148, 153. Morrell (US), 181, 184. Morning-Post (GB), 85. N No. i (GB), 45, 154, 155. No. 2 (GB), 112, 113. No. 2A (GB), 151. No. 3 (GB), 32, 67. No. 4 (GB), 157, 158. No. I, i-bis (I), 157. No. i (US), 174, 175. Nulli-Seciindus (GB), 150, 151. Outchebny (R), 169. P. I (D), 106, 105. P. II (D), 106, 109. P. Ill (D), III. P. IV (D), 113. P. V (D), 113. P. i P. 5 (D. 159, 160. Pasadena (US), 180, 181. Patrie (F), 82, 83. Pax (BR), 94, 95- Petit-Journal I, II (F), 99. Pilatre-de-Rozier (F), 69. PL. i (D), 106, 107. PL. 5 (D), 108, 109. PL. 9 (D), 108, in. PL. 10 (D), in. Preble-Rekar (US), 183. O P R. I-III (D), 119. Republique (F), 83. Robert-Fillet (F), 89. Russie (R), 85. Sachsen (D), 135. Santa Cruz (BR), 59. Santos- Dumont No. 1-16 (BR), 90-93. Schwaben (D), 5, 131, 210. Schwarz No. I (OE), 123. Schwarz No. 2 (OE), 116, 123. SL. I (D), 43, 118, 119, 120. SL. II (D), 116, 121. SL. Ill (D), 121. Sokol (R), 171. Spencer II (GB), 153. Spiess (F), 100, 101. SS. I (D), 31, 122, 124, 125. S. S. type (GB), 69, 70. Stollwerck (D), 108, 109. Suchard (D), 102, 104, 105. Tchaika (R), 101. Tissandier (F), 87, 96, 97. Toliver (US), 183. Tomlinson (US), 175. Torres-Quevedo (E), 172, 173. U Unger (D), 125. Usuelli (I), 164, 165. V. I (I), 161. Veeh I (D), 104, 107. Viktoria-Luise (D), 133. Ville-de-Bordeaux (F), 63. Ville-de-Bruxelles (B), 65, 66. Ville-de-Lucerne (F), 65. Ville-de-Nancy (F), 63. Ville-de-Paris (F), 61, 62, 96, 97. Ville-de-Pau (F), 62, 65. Ville-de-Saint-Mandd (F), 77. 231 w Willows No. i-No. 5 (GB),' 155-158. Y Yamada No. 1,2 (J), 166, 167. Yastreb (R), 168, 169. Yuhi (J), III. Z Z. I (D), 129, 133, 135- Z. II (D), 129, 131,132- Z. Ill (D), 133. Z. IV (D), 135, 136. Z. V (D), 135. Z. VI-XIII (D), 137. Z. 48 (D), 203. Zeppelin I (D), 126, 127. Zeppelin II (D), 127, 128. Zeppelin III (D), 128, 129. Zodiac (B), 99. Zodiac (F), 99. Zorn (D), 147. 232 YC 68298 UNIVERSITY OF CALIFORNIA LIBRARY