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AEROPLANES AND DIRIGIBLES OF WAR
By the same Author. Uniformly bound, Demy 8vo.
MOVING PICTURES: How they are Made and Worked.
LIGHTSHIPS AND LIGHTHOUSES.
THE STEAMSHIP CONQUEST OF THE WORLD.
THE RAILWAY CONQUEST OF THE WORLD.
ALSO
PRACTICAL CINEMATOGRAPHY.
Crown 8yo.
Philadelphia : J. B. LIPPINCOTT COMPANY
AEROPLANES AND DIRIGIBLES OF WAR
BY
FREDERICK A. TALBOT
AUTHOR OF "moving PICTURES," ETC.
PHILADELPHIA: J. B. LIPPINCOTT COMPANY
LONDON: WILLIAM HEINEMANN
MCMXV
r3
PriHted in Great Britain.
PREFACE
Ever since the earliest days of the great conquest of the air, first by *he dirigible balloon and then by the aeroplane, their use in time of war has been a fruitful theme for discussion. But their arrival was of too recent a date, their many utilities too unexplored to provide anything other than theories, many obviously untenable, others avowedly problem- atical.
Yet the part airships have played in the Greatest War has come as a surprise even to their most con- vinced advocates. For every expectation shattered, they have shown a more than compensating possi- bihty of usefulness.
In this volume an endeavour has been made to record their achievements, under the stern test of trial, as an arm of war, and to explain, in untechnical language, the many services to which they have been and may be applied.
In the preparation of the work I have received assistance from many sources — British, French, Russian and German — from official reports and from
358029
vi PREFACE
men who have played a part in the War in the Air. The information concerning German mihtary air- craft has been obtained from Government documents, most of which were placed at my disposal before the outbreak of war.
The use of aircraft has changed the whole art and science of warfare. With its disabilities well in hand, with its strength but half revealed, the aerial service has revolutionised strategy and shorn the unexpected attack of half its terrors. The Fourth Arm is now an invaluable part of the complex
military machine.
F. A. TALBOT.
CONTENTS
CHAP. PAGE
I. THE INTRODUCTION OF AIRCRAFT INTO MILI- TARY OPERATIONS I
II. THE MILITARY USES OF THE CAPTIVE BALLOON 1 1
III. GERMANY'S RISE TO MILITARY AIRSHIP SUPRE-
MACY 25
IV. AIRSHIPS OF WAR 41
V. GERMANY'S AERIAL DREADNOUGHT FLEET . 58
VI. THE MILITARY VALUE OF GERMANY'S AERIAL
FLEET 70
VII. AEROPLANES OF WAR 81
VIIL SCOUTING FROM THE SKIES . . . . . 94
IX. THE AIRMAN AND ARTILLERY . . . . II4
X. BOMB-THROWING FROM AIR-CRAFT . . . I24
XI. ARMOURED AEROPLANES I44
XII. BATTLES IN THE AIR 1 58
XIII. TRICKS AND RUSES TO BAFFLE THE AIRMAN . 1 73
XIV. ANTI-AIRCRAFT GUNS. MOBILE WEAPONS . 1 85
vii
viii CONTENTS
CHAP. PAGE
XV. ANTI-AIRCRAFT GUNS. IMMOBILE WEAPONS . I99
XVI. MINING THE AIR 217
XVII WIRELESS IN AVIATION 229
XVIII. AIRCRAFT AND NAVAL OPERATIONS . . . 243
XIX. THE NAVIES OF THE AIR 260
INDEX . . . . 277
LIST OF ILLUSTRATIONS
FACING PAGB
The Military Area of Flanders as seen from an Aeroplane Frontispiece
A British Military Reconnoitring Balloon going Aloft . 8
Cylinders of Hydrogen for Inflating a British Captive
Military Reconnoitring Balloon 9
One of the Greatest Zeppelins for Passenger Service —
The " Schwaben " 28
A Schiitte-Lanz Rigid Dirigible issuing from its Shed . 29
German Airship of the Schiitte-Lanz Type in Course of
Construction 42
Schiitte-Lanz type of Dirigible entering its Shed . . 43
The British Dirigible " Gamma " at Anchor ... 54
The Car of a British Military Dirigible . . . . 55
Belgian Mechanics Repairing an Aeroplane Engine at
the Aviation Base of the Allies in the North of
France 76
A Military Aeroplane Repair Workshop in the North of
France 'J^
German Albatross Waterplane 84
Launching a White Seaplane showing the Floats and
Staying System 85
A French Aeroplane Base behind the Trenches . . 88 The " Short " type of British Seaplane which has proved
so successful 89
Full Speed Ahead !] , 100
IX
X LIST OF ILLUSTRATIONS
FACING PAGE
Belgian Aviator Handing Results of a Reconnaissance
to a Motor Despatch-Rider loi
The"Fl^chette"or Steel Dart 126
A Zeppelin Bomb 126
Nose of the Grenade showing Fuse-head Mechanism . 127
Section of Zeppelin Hand Grenade 127
A Hand-dropped Aeroplane Bomb 136
A Dart-shaped Bomb which is thrown from French
Aeroplanes 137
A British Aeroplane armed with a Vickers Gun . . 1 50 Unloading Bombs and Gasoline or Petrol from an
Aeroplane Supply Train 151
A British Aeroplane brought down in the North of
France 168
Transporting a Belgian VVarplane to the Aviation Base
in Northern France 169
"Archibald," the German Motor Mounted Anti-aircraft
Gun 192
Krupp-Armoured Motor-car with 7*1 centimetre Gun for
Fighting Aerial Craft 193
The latest Krupp Anti-aircraft Gun, showing Novel Dis- position of Wheels 206
French Soldiers with Machine Gun Firing upon Hostile
Aeroplanes 207
Warplane or Dreadnought ? 248
Seaplane Launching Platform on H.M.S. " Hibernia" . 249
IN TEXT
FIG. PAGE
1. Showing how Wind aflfects the Efficiency of the
Captive Balloon 12
2. Finding the Range of a Captive Balloon, First Round 19
3. Finding the Range of a Captive Balloon, Second
Round 20
4. Finding the Range of a Captive Balloon, Third Round 21
LIST OF ILLUSTRATIONS xi
FIG. PAGE
5. Finding the Range of a Captive Balloon, Fourth Round 2 1
6. Section through Torres Type of Dirigible showing
Form of Design and Construction .... 56
7. Bomb-dropping from a Rapidly-moving Aeroplane . 134
8. The Influence of an Adverse Wind upon the
Trajectory of the Bomb 135
9. Section of Upper End or Tail of ''Fl^chette" . . 141
10. How B, being able to Fire ahead, loses Advantage
by Overhauling A, because in Position 2 B comes within Range of Gun of A 153
11. The Advantage of both Ahead and Astern Gun-fire 154
12. The " Smoke Screen " in the Air 172
13. The German Method of Picking up the Range with
Anti-aircraft Gun-fire 211
14. The German Method of Picking up the Range with
Anti-aircraft Guns 212
1 5. How the Fighting Zone is divided into Triangles to
secure Protection against Aerial Attack. An Anti- aircraft Gun is disposed at each corner . . . 215
CHAPTER I
THE INTRODUCTION OF AIRCRAFT INTO MILITARY OPERATIONS
It is a curious circumstance that an invention, which is hailed as being one of the greatest achieve- ments ever recorded in the march of civiHsation, should be devoted essentially to the maiming of humanity and the destruction of property. In no other trend of human endeavour is this factor so potently demonstrated as in connection with Man's Conquest of the Air.
The dogged struggle against the blind forces of Nature was waged tenaciously and perseveringly for centuries. But the measure of success recorded from time to time was so disappointing as to convey the impression, except in a limited circle, that the problem was impossible of solution.
In the meantime wondrous changes had taken place in the methods of transportation by land and sea. The steam and electric railway, steam pro-
B
2 AEROPLANES AND DIRIGIBLES
pulsion of vessels, and mechanical movement along the highroads had been evolved and advanced to a high standard of perfection, to the untold advantage of the community. Consequently it was argued, if only a system of travel along the aerial highways could be estabUshed, then all other methods of mechanical transportation would be rendered, if not entirely obsolete, at least antiquated.
At last man triumphed over Nature — at least to such a degree as to inspire the confidence of the world at large, and to bring aerial travel and trans- portation within range of reaHsation. But what has been the result ? The discovery is not devoted to the interests of peace and economic development, but to extermination and destruction.
At the same time this development may be explained. The airship and aeroplane in the present stage of evolution possess no economic value. True, cross-country cruises by airship have been in- augurated, and, up to a point, have proved popularly, if not commercially, successful, while tentative efforts have been made to utilise the aeroplane as a mail-carrier. Still, from the view-point of the community at large aerial travel is as remote as it was centuries ago.
It is somewhat interesting to observe how history is repeating itself. When the Montgolfiers succeeded in lifting themselves into the air by means of a vessel inflated with hot air, the new vehicle was hailed not so much as one possessed of commercial possi-
THE CAPTIVE BALLOON 3
bilities, but as an engine of war ! When the in- domitable courage and perseverance of Count von Zeppelin in the face of discouraging disasters and flagrant failures, at last commanded the attention of the German Emperor, the latter regarded the Zeppelin craft, not from the interests af peace, but as a military weapon, and the whole of the subse- quent efforts of the Imperial admirer were devoted to the perfection of the airship in this one direction.
Other nations, when they embarked on an identical line of development, considered the airship from a similar point of view. In fact, outside Germany, there was very little private initiative in this field. Experiments and developments were undertaken by the mihtary or naval, and in some instances by both branches, of the respective Powers. Conse- quently the aerial craft, whether it be a dirigible airship, or an aeroplane, can only be regarded from the military point of view.
Despite the achievements which have been re- corded by human endeavour in the field of aerial travel, the balloon per se has by no means been superseded. It still remains an invaluable adjunct to the fighting machine. In Great Britain its value in this, direction has never been ignored : of late, indeed, it has rather been developed. The captive balloon is regarded as an indispensable unit to both field and sea operations. This fact was emphasised very strongly in connection with the British naval attacks upon the German forces
B 2
4 AEROPLANES AND DIRIGIBLES
in Flanders, and it contributed to the dis- comfiture of the German hordes in a very emphatic manner.
The captive balloon may be operated from any spot where facilities exist for anchoring the paying- out cable together with winding facilities for the latter. Consequently , if exigencies demand, it may be operated from the deck of a warship so long as the latter is stationary, or even from an automobile. It is of small cubic capacity, inasmuch as it is only necessary for the bag to contain sufficient gas to lift one or two men to a height of about 500 or 600 feet.
When used in the field the balloon is generally inflated at the base, to be towed or carried forward by a squad of men while floating in the air, perhaps at a height of 10 feet. A dozen men will suffice for this duty as a rule, and in calm weather little difficulty is encountered in moving from point to point. This method possesses many advantages. The balloon can be inflated with greater ease at the base, where it is immune from interference by hostile fire. Moreover, the facihties for obtaining the requisite inflating agent — ^hydrogen or coal gas — are more convenient at such a point. If the base be far removed from the spot at which it is desired to operate the balloon, the latter is inflated at a convenient point nearer the requisite position, advantage being taken of the protective covering offered by a copse or other natural obstacle.
BRITISH AND FRENCH BALLOONS 5
As is well known, balloons played an important part during the siege of Paris in 1 870-1, not only in connection with daring attempts to communicate with the outer world, but in reconnoitring the German positions around the beleaguered city. But this was not the first military application of the aerial vessel ; it was used by the French against the Austrians in the battle of Fleurus, and also during the American Civil War. These operations, however, were of a sporadic character ; they were not part and parcel of an organised military section.
It is not generally known that the British War Office virtually pioneered the military use of balloons, and subsequently the methods perfected in Britain became recognised as a kind of " standard " and were adopted generally by the Powers with such modifications as local exigencies seemed to demand.
The British military balloon department was inaugurated at Chatham under Captain Templer in 1879. I^ was devoted essentially to the employ- ment of captive balloons in war, and in 1880 a company of the Royal Engineers was detailed to the care of this work in the field. Six years pre- viously the French military department had adopted the captive balloon under Colonel Laussedat, who was assisted among others by the well-known Captain Renard. Germany was somewhat later in the field ; the military value of captive balloons
6 AEROPLANES AND DIRIGIBLES
was not appreciated and taken into serious consideration here until 1884. But although British efforts were preceded by the French the latter did not develop the idea upon accepted military lines.
The British authorities were confronted with many searching problems. One of the earliest and greatest difficulties encountered was in con- nection with the gas for inflation. Coal gas was not always readily available, so that hydrogen had to be depended upon for the most part. But then another difficulty arose. This was the manu- facture of the requisite gas. Various methods were tested, such as the electrolytic decomposition of water, the decomposition of sulphuric acid by means of iron, the reaction between slaked lime and zinc, and so forth.
But the drawbacks to every process, especially upon the field of battle, when operations have to be conducted under extreme difficulties and at high pressure, were speedily recognised. While other nations concentrated their energies upon the simplification of hydrogen-manufacturing apparatus for use upon the battle-field. Great Britain abandoned all such processes in toto. Our military organisation preferred to carry out the production of the necessary gas at a convenient manufacturing centre and to transport it, stored in steel cylinders under pressure, to the actual scene of operations. The method proved a great success, and in this way it was found
CAPTAIN TEMPLER 7
possible to inflate a military balloon in the short space of 20 minutes, whereas, under the conditions of making gas upon the spot, a period of four hours or more was necessary, owing to the fact that the manufacturing process is relatively slow and intricate. The practicability of the British idea and its per- fection served to establish the captive balloon as a military unit.
The British military ballooning department has always ranked as the foremost of its type among the Powers, although its work has been carried out so unostentatiously that the outside world has gleaned very little information concerning its oper- ations. Captain Templer was an indefatigable worker and he brought the ballooning section to a high degree of efficiency from the military point of view.
But the British Government was peculiarly favoured, if such a term may be used. Our little wars in various parts of the world contributed valuable information and experience which was fully turned to account. Captive balloons for reconnoitring purposes were used by the British army for the first time at Suakim in 1885, and the section established its value very convincingly. The French military balloon department gained its first experience in this field in the previous year, a balloon detachment having been dispatched to Tonkin in 1884. In both the Tonkin and Soudan campaigns, invaluable work was accomplished by
8 AEROPLANES AND DIRIGIBLES
the balloon sections, with the result that this aerial vehicle has come to be regarded as an indispensable military adjunct. Indeed the activity of the German military ballooning section was directly attributable to the Anglo-French achievements therewith.
In this work, however, the British force speedily displayed its superiority and initiative. The use of compressed hydrogen was adopted, and within the course of a few years the other Powers, realising the advantages which the British department had thus obtained, decided to follow its example. The gas is stored in cylinders under a pressure varying from six to ten or more atmospheres ; in other words from about 80 to 140 or more pounds per square inch. Special military wagons have been designed for the transport of these cylinders, and they are attached to the balloon train.
The balloon itself is light, and made of such materials as to reduce the weight thereof to the minimum. The British balloons are probably the smallest used by any of the Powers, but at the same time they are the most expensive. They are made of goldbeater's skin, and range in capacity from 7,000 to 10,000 cubic feet, the majority being of the former capacity. The French balloon on the other hand has a capacity exceeding 18,000 cubic feet, although a smaller vessel of 9,000 cubic feet capacity, known as an auxiliary, and carrying a single observer, is used.
* » 5, » * » •
V ' ) • 1
A British Military Reconnoitring Balloon GOING Aloft.
BALLOONS IN THE BOER WAR 9
The Germans, on the other hand, with their Teutonic love of the immense, favour far larger vessels. At the same time the military balloon section of the German Army eclipses that of any other nation, is attached to the Intelligence Depart- ment, and is under the direct control of the General Staff. Balloon stations are dotted all over the country, including Heligoland and Kiel, while regular sections are attached to the Navy for operating captive balloons from warships. Although the Zeppelin and aeroplane forces have come to the front in Germany, and have relegated the captive balloon somewhat to the limbo of things that were, the latter section has never been disbanded ; in fact, during the present campaign it has undergone a somewhat spirited revival.
The South African campaign emphasised the value of the British balloon section of the Army, and revealed services to which it was specially adapted, but which had previously more or less been ignored. The British Army possessed indifferent maps of the Orange Free State and the Transvaal. This lamentable deficiency was remedied in great measure by recourse to topographical photographs taken from the captive balloons. The gmdes thus ob- tained were found to be of extreme value.
During the early stages of the war the hydrogen was shipped in cylinders from the homeland, but subsequently a manufacturing plant of such capacity as to meet all requirements was established
10 AEROPLANES AND DIRIGIBLES
in South Africa. The cyHnders were charged at this point and dispatched to the scene of action, so that it became unnecessary to transport the commodity from Britain. The captive balloon revealed the impregnability of Spion Kop, enabled Lord Roberts to ascertain the position of the Boer guns at the Battle of Paardeburg, and proved of invaluable assistance to the forces of General White during the siege of Ladysmith.
CHAPTER II
THE MILITARY USES OF THE CAPTIVE BALLOON
Although the captive balloon is recognised as indispensable in military operations, its uses are somewhat limited. It can be employed only in comparatively still weather. The reason is obvious. It is essential that the balloon should assume a vertical line in relation to its winding plant upon the ground beneath, so that it may attain the maximum elevation possible : in other words, the balloon should be directly above the station below, so that if 100 yards of cable are paid out the aerostat may be 100 yards above the ground. If a wind is blow- ing, the helpless craft is certain to be caught thereby and driven forwards or backwards, so that it assumes an angle to its station. If this become acute the vessel will be tilted, rendering the position of the observers somewhat precarious, and at the same time observing efficiency will be impaired.
This point may be appreciated more easily by reference to the accompanying diagram. Fig. i. A represents the ground station and B the position
12 AEROPLANES AND DIRIGIBLES
of the captive balloon when sent aloft in calm weather, 300 feet of cable being paid out. A wind arises and blows the vessel forward to the position C. At this point the height of the craft in relation to the ground has been reduced, and the reduction must
B
Fig. I. — Showing how Wind affects the Efficiency OF THE Captive Balloon.
A, B, the position of the balloon in calm weather ; A, C, the position when wind is blowing from left.
increase proportionately as the strength of the wind increases and forces the balloon still more towards the ground. At the same time, owing to the tilt given to the car, observation is rendered
EQUIPMENT OF BALLOONS 13
more difficult and eventually becomes extremely dangerous.
A wind, if of appreciable strength, develops another and graver danger. Greater strain will be imposed upon the cable, while if the wind be gusty, there is the risk that the vessel will be torn away from its anchoring rope and possibly lost. Thus it will be seen that the effective utilisation of a captive balloon is completely governed by meteoro- logical conditions, and often it is impossible to use it in weather which exercises but little influence upon dirigibles or aeroplanes.
The captive balloon equipment comprises the balloon, together with the observer's basket, the wire-cable whereby it is anchored and controlled, and the winding apparatus. Formerly a steam engine was necessary for the paying in and out of the cable, but nowadays this is accomplished by means of a petrol-driven motor, an oil-engine, or even by the engine of an automobile. The length of cable varies according to the capacity of the balloon and the maximum operating height.
The average British balloon is able to lift about 290 or 300 pounds, which may be taken to represent the weight of two observers. On the other hand, the French and German balloons are able to carry four times this weight, with the exception of the French auxiharies, which are designed to lift one observer only. The balloons of the two latter Powers have also a greater maximum altitude; it is
14 AEROPLANES AND DIRIGIBLES
possible to ascend to a height of some 2,000 feet in one of these.
The observing station is connected with the winding crew below either by a telephone, or some other signalling system, the method practised varying according to circumstances. In turn the winding station is connected with the officer in charge of the artillery, the fire of which the captive balloon is directing. The balloon observer is generally equipped with various instruments, such as tele- scope, photographic cameras, and so forth, so as to be able, if necessary, to prepare a topographical survey of the country below. By this means the absence of reliable maps may be remedied, or if not regarded as sufficiently correct they may be checked and counter- checked by the data gained aloft.
Seeing that the gas has to be transported in cylinders, which are weighty, it is incumbent that the waste of this commodity should be reduced to the minimum. The balloon cannot be deflated at night and re-inflated in the morning — it must be maintained in the inflated condition the whole time it is required for operation.
There are various methods of consummating this end. One method is to haul in the balloon and to peg it down on all sides, completing the anchorage by the attachment of bags filled with earth to the network. While this process is satisfactory in calm weather, it is impracticable in heavy winds, which are likely to spring up suddenly. Consequently
SUPPLYING GAS 15
a second method is practised. This is to dig a pit into the ground of sufficient size to receive the balloon. When the latter is hauled in it is lowered into this pit and there pegged down and anchored. Thus it is perfectly safe during the roughest weather, as none of its bulk is exposed above the ground level. Furthermore it is not a conspicuous object for the concentration of hostile fire.
In some instances, and where the military depart- ment is possessed of an elaborate equipment such as characterises the German army, when reconnaissance is completed and the balloon is to be removed to another point, the gas is pumped back into the cylinders for further use. Such an economical proceeding is pretty and well adapted to manoeuvres, but it is scarcely feasible in actual warfare, for the simple reason that the pumping takes time. Consequently the general procedure, when the balloon has completed its work, is to permit the gas to escape into the air in the usual manner, and to draw a fresh supply of gas from further cyhnders when the occasion arises for re-iniiation.
Although the familiar spherical balloon has proved perfectly adequate for reconnoitring in the British and French armies, the German authorities main- tained that it was not satisfactory in anything but calm weather. Accordingly scientific initiative was stimulated with a view to the evolution of a superior vessel. These endeavours culminated in the Parse val-Siegsf eld captive balloon, which has
i6 AEROPLANES AND DIRIGIBLES
a quaint appearance. It has the form of a bulky cyHnder with hemispherical extremities. At one end of the balloon there is a surrounding outer bag, reminiscent of a cancerous growth. The lower end of this is open. This attachment serves the purpose of a ballonet. The wind blowing against the opening, which faces it, charges the ballonet with air. This action, it is claimed, serves to steady the main vessel, somewhat in the manner of the tail of a kite, thereby enabling observations to be made as easily and correctly in rough as in calm weather. The appearance of the balloon while aloft is certainly curious. It appears to be rearing up on end, as if the extremity saddled with the ballonet were weighted.
British and French captive balloon authorities are disposed to discount the steadying effect of this attachment, and, indeed, to maintain that it is a distinct disadvantage. It may hold the vessel steadier for the purpose of observation, but at the same time it renders the balloon a steadier target for hostile fire. On the other hand, the swaying of a spherical balloon with the wind materially contri- butes to its safety. A moving object, particularly when its oscillations are irregular and incalculable, is an extremely difficult object at which to take effective aim.
Seeing that even a small captive balloon is of appreciable dimensions — from 25 to 33 feet or more in diameter — one might consider it an easy object
ATTACKING METHODS 17
to hit. But experience has proved otherwise. In the first place the colour of the balloon is distinctly protective. The golden or yellowish tinge harmon- ises well with the daylight, even in gloomy weather, while at night-time it blends excellently with the moonlight. For effective observations a high alti- tude is undesirable. At a height of 600 feet the horizon is about 28 miles from the observer, as compared with the 3 miles constituting the range of vision from the ground over perfectly flat country. Thus it will be seen that the '* spotter " up aloft has the command of a considerable tract.
Various ways and means of finding the range of a captive balloon have been prepared, and tables innumerable are available for committal to memory, while those weapons especially designed for aerial targets are fitted with excellent range-finders and other instruments. The Germans, with character- istic thoroughness, have devoted considerable atten- tion to this subject, but from the results which they have achieved up to the present this guiding knowledge appears to be more spectacular and impressive than effective.
To put a captive balloon out of action one must either riddle the envelope, causing it to leak like a sieve, blow the vessel to pieces, or ignite the highly inflammable gas with which it is inflated. Individual rifle fire will inflict no tangible damage. A bullet, if it finds its billet, will merely pass through the envelope and leave two small punctures. True,
c
i8 AEROPLANES AND DIRIGIBLES
these vents will allow the gas to escape, but this action will proceed so slowly as to permit the vessel to remain aloft long enough to enable the observer to complete his work. A lucky rifle volley, or the stream of bullets from a machine gun may riddle the envelope, precipitating a hurried descent, owing to the greater number of perforations through which the gas is able to escape, but as a rule the observer will be able to land safely.
Consequently the general practice is to shatter the aerostat, and to this end either shrapnel, high explosive, or incendiary shells will be used. The former must explode quite close to the balloon in order to achieve the desired end, while the incendiary shell must actually strike it, so as to fire the gas. The high explosive shell may explode effectually some feet away from the vessel, inasmuch as in this instance dependence is placed upon the terrific concussion produced by the explosion which, acting upon the fragile fabric of the balloon, brings about a complete collapse of the envelope. If a shrapnel is well placed and explodes immediately above the balloon, the envelope will be torn to shreds and a violent explosion of the gas will be precipitated. But as a matter of fact, it is extremely difficult to place a shrapnel shell so as to consummate this end. The range is not picked up easily, while the timing of the fuse to bring about the explosion of the shell at the critical moment is invariably a complex problem.
ATTACKS ON BALLOONS
19
One favourite method of finding the range of a balloon is shown in the accompanying diagrams, Figs. 2 to 5. The artillery battery is at B and the captive balloon, C, is anchored at A. On either side of B and at a specified distance, observers Oj and O2 respectively are stationed. First a shell is fired at " long " range, possibly the maximum range
%
Fig. 2.— Finding the Range of a Captive Balloon. First Round, with Shell Timed at Long Range.
(For explanation see text. )
of the gun. It bursts at D (Fig. 2). As it has burst immediately in the line of sight of B, but with the smoke obscured by the figure of the balloon C, it is obvious to B that the explosion has occurred behind the objective, but at what distance he cannot tell. To O^ and Og, however, it is seen to have burst at a considerable distance behind C,
c 2
20 AEROPLANES AND DIRIGIBLES
though to the former it appears to have burst to the left and to the second observer to the right of the target.
Another shell, at " short " range, is now fired, and it bursts at E. The explosion takes place in the line of sight of B, who knows that he has fired short of the balloon because the latter is eclipsed by the smoke. But the two observers see that it is very
«c
\
'4n
\
0, B 02
Fig. 3.— Finding the Range of a Captive Balloon. Second Round, with Shell Timed at Short Range.
(For explanation see text.)
short, and here again the explosion appears to O^ to have occurred to the right of the target, while to Og it has evidently burst to the left of the aerostat, as revealed by the relation of the position of the balloon to the bursting of the shell shown in Fig. 3. A third round is fired, and the shell explodes at F. In this instance the explosion takes place below the balloon. Both the observers and the artillery-
SHELLING BALLOONS
21
man concur in their deductions upon the point at which the shell burst (Fig. 4). But the shell must
\
\\.
\
\
Fig. 4.— Finding the Range of a Captive Balloon. Third Round. (For explanation see text.)
X
\
\
Fig. 5. — Finding the Range of a Captive Balloon. Fourth Round. (For explanation see text.)
explode above the balloon, and accordingly a fourth round is discharged and the shell bursts at G (Fig. 5).
22 AEROPLANES AND DIRIGIBLES
This appears to be above the balloon, inasmuch as the lines of sight of the two observers and B corf- verge at this point. But whether the explosion occurs immediately above the vessel as is desired, it is impossible to say definitely, because it may explode too far behind to be effective. Consequently, if this shell should prove abortive, the practice is to decrease the range gradually with each succeeding round until the explosion occurs at the critical point, when, of course, the balloon is destroyed. An interesting idea of the difficulty of picking up the range of a captive balloon may be gathered from the fact that some ten minutes are required to complete the operation.
But success is due more to luck than judgment. In the foregoing explanation it is premised that the aerial vessel remains stationary, which is an ex- tremely unlikely contingency. While those upon the ground are striving to pick up the range, the observer is equally active in his efforts to baffle his opponents. The observer follows each successive round with keen interest, and when the shells appear to be bursting at uncomfortably close quarters naturally he intimates to his colleagues below that he desires his position to be changed, either by ascending to a higher point or descending. In fact, he may be content to come to the ground. Nor must the fact be overlooked that while the enemy is trying to place the observer hors de combat, he is revealing the position of his artillery, and the
DIFFICULTIES OF ATTACK 23
observer is equally industrious in picking up the range of the hostile guns for the benefit of his friends below.
When the captive balloon is aloft in a wind the chances of the enemy picking up the range thereof are extremely slender, as it is continually swinging to and fro. While there is always the possibility of a shell bursting at such a lucky moment as to demolish the aerial target, it is generally conceded to be impossible to induce a shell to burst within 100 yards of a balloon, no matter how skilfully the hostile battery may be operated.
The value of the captive balloon has been demon- strated very strikingly throughout the attack upon the entrenched German positions in Flanders. Owing to the undulating character of the dunes the " spotters " upon the British monitors and battle- ships are unable to obtain a sweeping view of the country. Accordingly captive balloons are sent aloft in some cases from the deck of the monitors, and in others from a suitable point upon the beach itself. The aerial observer from his point of vantage is able to pick up the positions of the German forces and artillery with ease and to communicate the data thus gained to the British vessels, although subjected to heavy and continuous hostile fire. The difficulty of hitting a captive balloon has been graphically emphasised, inasmuch as the German artillerists have failed to bring down a sohtary balloon. On the other hand the observer in the
24 AEROPLANES AND DIRIGIBLES
air is able to signal the results of each salvo fired from the British battleships as they manoeuvre at full speed up and down the coastline, while he keeps the fire of the monitors concentrated upon the German positions until the latter have been rendered untenable or demolished. The accuracy of the British gun-fire has astonished even the Germans, but it has been directly attributable to the range- finder perched in the car of the captive balloon and his rapid transmission of information to the vessels below.
The enthusiastic supporters of aerial navigation maintained that the dirigible and the aeroplane would supersede the captive balloon completely. But as a matter of fact the present conflict has estab- Ushed the value of this factor more firmly than ever. There is not the slightest possibility that the captive balloon sections of the belligerents will be disbanded, especially those which have the fruits of experience to guide them. The airship and the aeroplane have accomplished wonders, but despite their achievements the captive balloon has fully sub- stantiated its value as a military unit in its particular field of operations.
CHAPTER III
GERMANY'S RISE TO MILITARY AIRSHIP SUPREMACY
Two incidents in the history of aviation stand out with exceptional prominence. The one is the evolution of the Zeppelin airship — a story teeming with romance and affording striking and illuminating glimpses of dogged perseverance, grim determination in the face of repeated disasters, and the blind courageous faith of the inventor in the creation of his own brain. The second is the remarkable growth of Germany's military airship organisation, which has been so rapid and complete as to enable her to assume supremacy in this field, and that within the short span of a single decade.
The Zeppehn has always aroused the world's attention, although this interest has fluctuated. Regarded at first as a wonderful achievement of genius, afterwards as a freak, then as the ready butt for universal ridicule, and finally with awe, if not with absolute terror — such in brief is the history of this craft of the air.
26 AEROPLANES AND DIRIGIBLES
Count von Zeppelin can scarcely be regarded as an ordinary man. He took up the subject of flight at an age which the majority of individuals regard as the opportune moment for retirement from activity, and, knowing nothing about mechanical engineering, he concentrated his energies upon the study of this science to enable him to master the difficulties of a mechanical character incidental to the realisation of his grand idea. His energy and indomitable perseverance are equalled by his ardent patriotism, because, although the Fatherland dis- counted his idea when other Powers were ready to consider it, and indeed made him tempting offers for the acquisition of his handiwork, he stoutly declined all such solicitations, declaring that his invention, if such it may be termed, was for his own country and none other.
Count von Zeppelin developed his line of study and thought for one reason only. As an old cam- paigner and a student of military affairs he realised the shortcomings of the existing methods of scouting and reconnoitring. He appreciated more than any other man of the day perhaps, that if the commander- in-chief of an army were provided with facilities for gazing down upon the scene of operations, and were able to take advantage of all the information accruing to the man above who sees all, he would hold a superior position, and be able to dispose his forces and to arrange his plan of campaign to the most decisive advantage. In other words, Zeppelin
COUNT VON ZEPPELIN 27
conceived and developed his airship for one field of application and that alone — military operations. Although it has achieved certain successes in other directions these have been subsidiary to the primary intention, and have merely served to emphasise its military value.
Von Zeppelin was handicapped in his line of thought and investigation from the very first. He dreamed big things upon a big scale. The colossal always makes a peculiar and irresistible appeal to the Teutonic nature. So he contemplated the perfection of a big dirigible, eclipsing in every respect anything ever attempted or likely to be attempted by rival countries. Unfortunately, the realisation of the " colossal " entails an equally colossal financial reserve, and the creator of this form of airship for years suffered from financial cramp in its worst manifestation. Probably it was to the benefit of the world at large that Fortune played him such sorry tricks. It retarded the growth of German ambitions in one direction very effectively.
As is well known Zeppelin evolved what may be termed an individual line of thought in connection with his airship activities. He adopted what is known as the indef ormable airship : that is to say the rigid, as opposed to the semi-rigid and flexible craft. As a result of patient experiment and con- tinued researches he came to the conclusion that a huge outer envelope taking the form of a polygonal cylinder with hemispherical ends, constructed upon
28 AEROPLANES AND DIRIGIBLES
substantial lines with a metallic skeleton encased within an impermeable skin, and charged with a number of smaller balloon-shaped vessels con- taining the lifting agent — hydrogen gas — would fulfil his requirements to the greatest advantage. Model after model was built upon these lines. Each was subjected to searching tests with the invariable result attending such work with models. Some fulfilled the expectations of the inventor, others resolutely declined to illustrate his reasonings in any direction.
The inevitable happened. When a promising model was completed finally the inventor learned to his sorrow what every inventor realises in time. His fortune and the resources of others had been poured down the sink of experiment. To carry the idea from the model to the practical stage required more money, and it was not forthcoming. The inventor sought to enlist the practical sympathy of his country, only to learn that in Germany, as in other lands, the axiom concerning the prophet, honour, and country prevails. No exuberant in- ventor received such a cold douche from a Govern- ment as did Count Zeppelin from the Prussian authorities. For two years further work was brought practically to a standstill : nothing could be done unless the sinews of war were forthcoming. His friends, who had assisted him financially with his models, now concluded that their aid had been misplaced.
ZEPPELIN'S EXPERIMENTS 29
The inventor, though disappointed, was by no means cast down. He clung tenaciously to his pet scheme and to such effect that in 1896 a German Engineering Society advanced him some funds to continue his researches. This support sufficed to keep things going for another two years, during which time a full-sized vessel was built. The grand idea began to crystallise rapidly, with the result that when a public company was formed in 1898, sufficient funds were rendered available to enable the first craft to be constructed. It aroused con- siderable attention, as well it might, seeing that it eclipsed anything which had previously been attempted in connection with dirigibles. It was no less than 420 feet in length, by 38 feet in diameter, and was fitted with two cars, each of which carried a sixteen horse-power motor driving independent propellers rigidly attached to the body of the vessel. The propellers were both vertical and horizontal, for the purpose of driving the ship in the two planes — vertical and horizontal respectively.
The vessel was of great scientific interest, owing to the ingenuity of its design and construction. The metallic skeleton was built up from aluminium and over this was stretched the fabric of the envelope, care being observed to reduce skin friction, as well as to achieve impermeability. But it was the internal arrangement of the gas-lifting balloons which provoked the greatest concern. The hull was divided into compartments, each complete
30 AEROPLANES AND DIRIGIBLES
in itself, and each containing a small balloon inflated with hydrogen. It was sub-division as practised in connection with vessels ploughing the water applied to aerial craft, the purpose being somewhat the same. As a ship of the seas will keep afloat so long as a certain number of its sub- divisions remain watertight, so would the Zeppelin keep aloft if a certain number of the gas compart- ments retained their charges of hydrogen. There were no fewer than seventeen of these gas-balloons arranged in a single line within the envelope. Beneath the hull and extending the full length of the latter was a passage which not only served as a corridor for communication between the cars, but also to receive a weight attached to a cable worked by a winch. By the movement of this weight the bow or stern of the vessel could be tilted to assist ascent and descent.
The construction of the vessel subsequently proved to be the easiest and most straightforward part of the whole undertaking. There were other and more serious problems to be solved. How would such a monster craft come to earth ? How could she be manipulated upon the ground ? How could she be docked ? Upon these three points previous experience was silent. One German inventor who likewise had dreamed big things, and had carried them into execution, paid for his temerity and ambitions with his life, while his craft was reduced to a mass of twisted and torn metal. Under these
FIRST ASCENT OF A ZEPPELIN 31
circumstances Count Zeppelin decided to carry out his flights over the waters of the Bodensee and to house his craft within a floating dock. In this manner two uncertain factors might be effectively subjugated.
Another problem had been ingeniously overcome. The outer envelope presented an immense surface to the atmosphere, while temperature was certain to play an uncertain part in the behaviour of the craft. The question was to reduce to the minimum the radiation of heat and cold to the bags containing the gas. This end was achieved by leaving a slight air space between the inflated gas balloons and the inner surface of the hull.
The first ascent was made on July 2nd, 1900, but was disappointing, several breakdowns of the mechanism occurring while the vessel was in mid-air, which rendered it unmanageable, although a short flight was made which sufficed to show that an independent speed of 13 feet per second could be attained. The vessel descended and was made fast in her dock, the descent being effected safely, while manoeuvring into dock was successful. At least three points about which the inventor had been in doubt appeared to be solved — ^his airship could be driven through the air and could be steered ; it could be brought to earth safely ; and it could be docked.
The repairs to the mechanism were carried out and on October 17th and 21st of the same year
32 AEROPLANES AND DIRIGIBLES
further flights were made. By this time certain influential Teuton aeronautical experts who had previously ridiculed Zeppehn's idea had made a perfect volte-face. They became staunch admirers of the system, while other meteorological savants participated in the trials for the express purpose of ascertaining just what the ship could do. As a result of elaborate trigonometrical calculations it was ascertained that the airship attained an indepen- dent speed of 30 feet per second, which exceeded anything previously achieved. The craft proved to be perfectly manageable in the air, and answered her helm, thus compljdng with the terms of dirigi- bility. The creator was flushed with his triumph, but at the same time was doomed to experience misfortune. In its descent the airship came to " earth " with such a shock that it was extensively damaged. The cost of repairing the vessel was so heavy that the company decHned to shoulder the liability, and as the Count was unable to defray the expense the wreck was abandoned.
Although a certain meed of success had been achieved the outlook seemed very black for the inventor. No one had any faith in his idea. He made imploring appeals for further money, em- barked upon lecturing campaigns, wrote aviation articles for the Press, and canvassed possible sup- porters in the effort to raise funds for his next enterprise. Two years passed, but the fruits of the propaganda were meagre. It was at this juncture,
THE EMPEROR AND ZEPPELIN 33
when everything appeared to be impossible, that Count ZeppeUn discovered his greatest friend. The German Emperor, with an eye ever fixed upon new developments, had followed Zeppelin's uphill struggle, and at last, in 1902, came to his aid by writing a letter which ran : —
" Since your varied flights have been reported to me it is a great pleasure to me to express my acknow- ledgment of your patience and your labours, and the endurance with which you have pressed on through manifold hindrances till success was near. The advantages of your system have given your ship the greatest attainable speed and dirigibility, and the important results you have obtained have produced an epoch-making step forward in the construction of airships and have laid down a valuable basis for future experiments."
This Imperial appreciation of what had been accomplished proved to be the turning point in the inventor's fortunes. It stimulated financial support, and the second airship was taken in hand. But misfortune still pursued him. Accidents were of almost daily occurrence. Defects were revealed here and weaknesses somewhere else. So soon as one trouble was overcome another made itself manifest. The result was that the whole of the money collected by his hard work was expended before the ship could take to the air. A further crash and blasting of cherished hopes appeared imminent, but at this moment another Royal personage came to the inventor's aid.
D
34 AEROPLANES AND DIRIGIBLES
The King of Wiirtemberg took a personal interest in his subject's uphill struggle, and the Wiirtemberg Government granted him the proceeds of a lottery. With this money, and with what he succeeded in raising by hook and by crook, and by mortgaging his remaining property, a round £20,000 was obtained. With this capital a third ship was taken in hand, and in 1905 it was launched. It was a distinct improvement upon its predecessors. The airship was 414 feet in length by 38 feet in diameter, was equipped with 17 gas balloons having an aggre- gate capacity of 367,000 cubic feet of hydrogen, was equipped with two 85 horse-power motors driving four propellers, and displaced 9 tons. All the im- perfections incidental to the previous craft had been eliminated, while the ship followed improved lines in its mechanical and structural details.
The trials with this vessel commenced on November 30th, 1905, but ill-luck had not been eluded. The airship was moored upon a raft which was to be towed out into the lake to enable the dirigible to ascend. But something went wrong with the arrangements. A strong wind caught the ungainly airship, she dipped her nose into the water, and as the motor was set going she was driven deeper into the lake, the vessel only being saved by hurried deflation.
Six weeks were occupied in repairs, but another ascent was made on January 17th, 1906. The trials were fairly satisfactory, but inconclusive. One of the motors went wrong, and the longitudinal stability
LOSS OF THIRD ZEPPELIN 35
was found to be indifferent. The vessel was brought down, and was to be anchored, but the Fates ruled otherwise. A strong wind caught her during the night and she was speedily reduced to indistin- guishable scrap.
Despite catastrophe the inventor wrestled gamely with his project. The lessons taught by one disaster were taken to heart, and arrangements to prevent the recurrence thereof incorporated in the suc- ceeding craft. Unfortunately, however, as soon as one defect was remedied another asserted itself. It was this persistent revelation of the unexpected which caused another period of indifference towards his invention. Probably nothing more would have been heard of the Zeppelin after this last accident had it not been for the intervention of the Prussian Government at the direct instigation of the Kaiser, who had now taken Count Zeppelin under his wing. A State lottery was inaugurated, the proceeds of which were handed over to the indefatigable inventor, together with an assurance that if he could keep aloft 24 hours without coming to earth in the meantime, and could cover 450 miles within this period, the Government would repay the whole of the money he had lavished upon his idea, and liquidate all the debts he had incurred in connection therewith.
Another craft was built, larger than its pre- decessors, and equipped with two motors developing 170 horse-power. Upon completion it was sub-
D 2
36 AEROPLANES AND DIRIGIBLES
mitted to several preliminary flights, which were so eminently successful that the inventor decided to make a trial trip under conditions closely analogous to those imposed for the Government test. On June 2oth, 1908, at 8.26 a.m. the craft ascended and remained aloft for 12 hours, during which time it made an encouraging circular tour. Flushed with this success, the Count considered that the official award was within reach, and that all his previous disasters and misfortunes were on the eve of re- demption.
The crucial test was essayed on August 5th, 1908. Accompanied by twelve observers the vessel ascended and travelled without incident for eight hours. Then a slight mishap demanded attention, but was speedily repaired, and was ignored officially as being too trivial to influence the main issue. Victory appeared within measurable distance : the arduous toil of many patient years was about to be rewarded. The airship was within sight of home when it had to descend owing to the development of another motor fault. But as it approached the ground. Nature, as if infuriated at the conquest, rose up in rebellion. A sudden squall struck the unwieldy monster. Within a few moments it became unmanageable, and through some inscrutable cause, it caught fire, with the result that within a few moments it was reduced to a tangled mass of metallic framework.
It was a catastrophe that would have completely vanquished many an inventor, but the Count was
TRIUMPH OF ZEPPELIN 37
saved the gall of defeat. His flight, which was remarkable, inasmuch as he had covered 380 miles within 24 hours, including two unavoidable descents, struck the Teuton imagination. The seeds so care- fully planted by the " Most High of Prussia " now bore fruit. The German nation sympathised with the indomitable inventor, appreciated his genius, and promptly poured forth a stream of subscriptions to enable him to build another vessel. The in- timation that other Powers had approached the Count for the acquisition of his idea became known far and wide, together with the circumstance that he had unequivocally refused all offers. He was striving for the Fatherland, and his unselfish patriotism appealed to one and all. Such an attitude deserved hearty national appreciation, and the members of the great German public emptied their pockets to such a degree that within a few weeks a sum of £300,000 or $1,500,000 was voluntarily subscribed.
All financial embarrassments and distresses were now completely removed from the Count's mind. He could forge ahead untrammelled by anxiety and worry. Another Zeppelin was built and it created a world's record. It remained aloft for 38 hours, during which time it covered 690 miles, and, although it came to grief upon alighting, by colliding with a tree, the final incident passed unnoticed. Germany was in advance of the world. It had an airship which could go anywhere, irrespective of
38 AEROPLANES AND DIRIGIBLES
climatic conditions, and in true Teuton perspective the craft was viewed from the miUtary standpoint. Here was a means of obtaining the mastery of the air : a formidable engine of invasion and aerial attack had been perfected. Consequently the Grand Idea must be supported with unbounded enthusiasm. The Count was hailed by his august master as *' The greatest German of the twentieth century," and in this appreciation the populace whole-heartedly concurred. Whether such a pane- gyric from such an auspicious quarter is praise indeed or the equivalent of complete condemnation, history alone will be able to judge, but when one reflects, at this moment, upon the achievements of this aircraft during the present conflagration, the unprejudiced will be rather inclined to hazard the opinion that Imperial Teuton praise is a synonym for damnation.
Although the Zeppelin was accepted as a perfect machine it has never been possible to disperse the atmosphere of disaster with which it has been enveloped from the first. Vessel after vessel has gone up in smoke and flame : few craft of this type have enjoyed more than an evanescent existence ; and each successive catastrophe has proved more terrible than its predecessor. But the Teutonic nation has been induced to pin its whole faith on this airship, notwithstanding that the more level- headed engineers of other countries have always maintained the craft to be a " mechanical mon-
OTHER TYPES 39
strosity " condemned from its design and principles of construction to disaster. Unshaken by this ad- verse criticism, Germany rests assured that by means of its ZeppeHns it will achieve that universal supre- macy which it is convinced is its Destiny.
This blind child-like faith has been responsible for the establishment and development of the Zeppelin factories.' At Friedrichshafen the facilities are adequate to produce two of these vessels per month, while another factory of a similar capacity has been established at Berlin. Unfortunately such big craft demand large docks to accommodate them, and in turn a large structure of this character con- stitutes an easy mark for hostile attack, as the raiding airmen of the Allies have proved very convincingly. But the Zeppelin must not be under-rated. Magnificent performances have been recorded by these vessels, such as the round 1,000 miles' trip in 1909, and several other equally brilliant feats since that date. It is quite true that each astounding achievement has been attended by an equally stupendous accident, but that is accepted as a mere incidental detail by the faithful Teutonic nation. Many vivid prophecies of the forthcoming flights by Zeppelin have been uttered, and it is quite probable that more than one will be fulfilled, but success will be attributable rather to accident than design.
Although the Zeppelin is the main stake of the German people in matters pertaining to aerial conquest, other types of airships have not been
40 AEROPLANES AND DIRIGIBLES
ignored, as related in another chapter. They have been fostered upon a smaller but equally effective scale. The semi-rigid Parse val and Gross craft have met with whole-hearted support, since they have established their value as vessels of the air, which is tantamount to the acceptance of their military value.
The Parseval is pronounced by experts to be the finest expression of aeronautical engineering so far as Teuton effort is concerned. Certainly it has placed many notable flights to its credit. The Gross airship is an equally serviceable craft, its lines of design and construction closely following those of the early French supple airships. There are several other craft which have become more or less recognised by the German nation as substantial units of war, such as the Ruthemberg, Siemens- Schukert, and so forth, all of which have proved their serviceability more or less conclusively. But in the somewhat constricted Teuton mind the Zeppelin and the Zeppelin only represents the ultima Thule of aerial navigation and the means for asserting the universal character of Pan- Germanism as well as " Kultur."
CHAPTER IV
AIRSHIPS OF WAR
So much has been said and written concerning the ZeppeHn airship, particularly in its military aspect, that all other developments in this field have sunk into insignificance so far as the general public is concerned. The Zeppelin dirigible has come to be generally regarded as the one and only form of practical light er-than-air type of aircraft. Moreover, the name has been driven home with such effect that it is regarded as the generic term for all German airships.
These are grievous fallacies. The Zeppelin is merely one of a variety of types, even in Germany, although at the moment it probably ranks as the solitary survivor of the rigid system of construction. At one time, owing to the earnestness with which the advantages of this form of design were discussed, and in view of the fact that the Zeppelin certainly appeared to triumph when all other designs failed, Great Britain was tempted to embrace the rigid form of construction. The building of an immense
4«
42 AEROPLANES AND DIRIGIBLES
vessel of this class was actively supported and it was aptly christened the " May-fly." Opponents of the movement tempered their emphatic condem- natory criticism so far as to remark that it may fly, but as events proved it never did. The colossal craft broke its back before it ever ventured into the air, and this solitary experience proving so disastrous, the rigid form of construction was abandoned once and for all. The venture was not in vain ; it brought home to the British authorities more convincingly than anything else that the Zeppelin was a mechanical monstrosity. The French never even contemplated the construction of such a craft at that time, estimating it at its true value, and the British failure certainly served to support French antagonism to the idea. Subsequently, however, an attempt at rigid construction was made in France with the " Spiess " airship, mainly as a concession to public clamour.
Even in Germany itself the defects of the Zeppelin were recognised and a decided effort to eliminate them was made by Professor Schiitte in co-operation with a manufacturer of Mannheim named Lanz. The joint product of their ambitions, the Schiitte- Lanz, is declared to be superior to the Zeppelin, but so far it has failed to justify any of the claims of its designers. This vessel, which also favours the colossal, is likewise of the rigid type, but realising the inherent dangers accruing from the employment of metal for the framework, its constructors have
, ^ , ' , c . -. • »
German Airshh" of the Schutte-Lanz type in Course of Construction.
3 =^
THE SHtJTTE-LANZ 43
used wood, reinforced and strengthened where necessary by metallic angle-iron, plates, and bracing ; this utilisation of metal is, however, carried out very sparingly. The first vessel of this class was a huge failure, while subsequent craft have not proved much more successful.
In fact, one of the largest German airships ever designed, L4, is, or rather was, a Schiitte-Lanz, with a capacity of 918,000 cubic feet, but over 6,000 pounds lighter than a Zeppelin of almost similar dimensions. I say " was " since L4 is no more. The pride of its creators evinced a stronger preference for Davy Jones' Locker than its designed realm. Yet several craft of this type have been built and have been mistaken for Zeppelins owing to the similarity of the broad principles of design and their huge dimensions. In one vital respect they are decidedly inferior to their contemporary — they are not so speedy.
The most successful of the German lighter-than-air machines are those known respectively as the semi- rigid and non-rigid types, the best examples of which are the Gross and Parse val craft. Virtually they are Teutonic editions of the successful French craft of identical design by which they were anticipated. The Lebaudy is possibly the most famous of the French efforts in this direction. The gas-bag has an asymmetrical shape, and is pointed at both ends, although the prow is blunter or rounder than the stern. The gas-bag comprises a single chamber for
44 AEROPLANES AND DIRIGIBLES
the inflating agent, the distended shape of the envelope being sustained by means of an air-ballonet. By varying the contents of the latter through the agency of a pump the tension of the gas in the lifting envelope can be maintained, and the shape of the inflated balloon preserved under all conditions.
Beneath the gas-bag is a long strengthened girder, and from this in turn the car is suspended. It is the introduction of this rigid girder which is re- sponsible for the descriptive generic term of " semi- rigid." On the other hand the " non-rigid '* type may be roughly described as a pisciform balloon fitted with propelUng machinery, inasmuch as the car containing the driving machinery is suspended from the balloon in the manner of the car in the ordinary drifting vessel. So far as the French effort is concerned the Bayard-Clement type is the best example of the non-rigid system ; it is repre- sented in Germany by the Parseval class.
The Gross airship has been definitely adopted as a military machine by the German authorities, and figures in the "M" class. The " M-IV " com- pleted in 1913 is the largest of this type, and differs from its prototypes in that it carries two cars, each fitted with motors, whereas the earlier machines were equipped with a single gondola after the French pattern. This vessel measures 320 feet in length, has a maximum diameter of 44^ feet, displaces 13 tons, and is fitted with motors det^eloping 450 horse-power, which is sufficient to give it a speed of
THE PARSEVAL 45
47 miles per hour. This vessel represents a huge advance upon its predecessors of this design, inas- much as the latter were about 245 feet in length by 36J feet in diameter, and displaced only six tons, while the single car was provided with a motor developing only 150 horse-power, the speed being 28 miles per hour. Thus it will be seen that a huge development has suddenly taken place, a result due no doubt to the co-operation of the well-known engineer Basenach. The " M-IV " is essentially an experiment and great secrecy has been maintained in regard to the trials which have been carried out therewith, the authorities merely vouchsafing the fact that the airship has proved completely successful in every respect ; conclusive testimony of this is offered by the inclusion of the vessel in the active aerial fleet of Germany.
But it is the Parseval which is regarded as the finest type of airship flying the German flag. This vessel is the product of slow evolution, for it is admitted to be a power-driven balloon. Even the broad lines of the latter are preserved, the shape being that of a cylinder with rounded ends. It is the direct outcome of the " Drachen-Balloon,'* perfected by Parseval and Siegsfeld, the captive balloon which is an indispensable part of the German military equipment.
The complete success of the suspension system in this captive balloon prompted Parseval to continue his researches and experiments in regard to the
46 AEROPLANES AND DIRIGIBLES
application of power to the vessel, so as to induce it to move independently of the wind. The sus- pension system and the car are the outstanding features of the craft. It is non-rigid in the strictest interpretation of the term, although, owing to the incorporation of the steadying hollow " mattress *' (as it is called by its inventor), the strength of the suspension system, and the substantial character of the car, it conveys an impression of great solidity. The thinnest rope, both manilla and steel, in the suspension system is as thick as a man's finger, while the car, measuring 30 feet in length by 6 feet in width, carried out in wood, is a striking example of the maximum of strength with the minimum of weight, being as steady and as solid as a boat's deck. The propellers are collapsible, although in the latest craft of this class they are semi-rigid.
The mechanical equipment is also interesting. There are two propellers, and two motors, each nominally driving one propeller. But should one motor break down, or motives of economy, such as husbanding of fuel, render it advisable to run upon one engine, then the two propellers may be driven by either of the motors.
The inventor has perfected an ingenious, simple, and highly efficient coupling device to attain this end, but to ensure that the propeller output is of the maximum efficiency in relation to the engine, the pitch of the propellers may be altered and even reversed while the engine is running. When one
THE PARSEVAL 47
motor only is being used, the pitch is lowered until the propellers revolve at the speed which they would attain if both engines were in operation. This adjustment of the propeller pitch to the most economical engine revolutions is a distinctive char- acteristic, and contributes to the efficiency and reliability of the Parseval dirigible to a very pro- nounced degree.
Steering in the vertical plane is also carried out upon distinctive lines. There are no planes for vertical steering, but movement is accomplished by tilting the craft and thus driving the gas from one end of the balloon to the other. This is effected by the manipulation of the air-ballonets, one of which is placed at the prow and stern of the gas bag respectively. If it is desired to descend the gas is driven from the forward to the after end of the envelope, merely by inflating the bow ballonet with air by means of a pump placed in the car. If ascent is required, the after-ballonet is inflated, thereby driving the gas to the forward end of the balloon, the buoyancy of which is thus increased. The outstanding feature of the " Drachen-Balloon " is incorporated in the airship. This is the auto- matic operation of the safety valve on the gas-bag directly by the air ballonet s. If these ballonets empty owing to the pressure of the gas within the envelope, a rope system disposed within the balloon and connecting the ballonets and the gas-valve at the top is stretched taut, thereby opening the
48 AEROPLANES AND DIRIGIBLES
gas- valve. In this manner the gas-pressure becomes reduced until the ballonets are enabled to exercise their intended function. This is a safety precaution ^ of inestimable value.
The Parseval is probably the easiest dirigible to handle, inasmuch as it involves no more skill or knowledge than that required for an ordinary free balloon. Its movements in the vertical plane are not dissimilar to those of the aeroplane, inasmuch as ascent and descent are normally conducted in a " screwing " manner, the only exception being of course in abrupt descent caused by the ripping of the emergency- valve. On one occasion, it is stated, one of the latest machines of this type, when conducting experimental flights, absolutely refused to descend, producing infinite amusement both among the crowd and those on board.
The development of the Parseval is directly attributable to the influence and intimate interest of the Kaiser, and undoubtedly this represents the wisest step he ever made in the realm of aero- nautics. It certainly has enabled the German military machine to become possessed of a significant fleet of what may be described as a really efficient and reliable type of dirigible. The exact number of military Parsevals in commission is unknown, but there are several classes thereof, in the nature of aerial cruisers and vedettes.
The largest and most powerful class are those known as the B type, measuring about 240 feet
PARSEVAL VEDETTES 49
in length by 40 feet maximum diameter, of 223,000 cubic feet capacity, and fitted with two motors and two propellers. This vessel carries about 10 passengers, can climb to a maximum height of approximately 8,500 feet, and is capable of remaining in the air for twenty hours upon a single fuel charge. While this is the largest and most serviceable type of Parseval designed for military duties, there is another, the A class, 200 feet in length with accom- modation for six passengers in addition to the crew of three, which is capable of attaining a maximum altitude of 6,700 feet, and has an endurance capacity of 15 hours. This class also is fitted with twin pro- pellers and motors. In addition there are the C and E classes, carrying from four to eight passengers, while the vedettes are represented by the D and F classes, which have a maximum altitude of 2,000 feet and can remain aloft for only five hours upon a single fuel charge. These smaller vessels, however, have the advantage of requiring only one or two men to handle them. The present military Parseval dirigible is made in one of these five standardised classes, experience having established their efficiency for the specified military services for which they are built. In point of speed they compare favourably with the latest types of Zeppelin, the speeds of the larger types ranging from 32 to 48 miles per hour with a motor effort of 360 to 400 horse-power.
So far as the French airships of war are concerned, the fleet is somewhat heterogeneous, although the
E
50 AEROPLANES AND DIRIGIBLES
non-rigid type prevails. The French aerial navy is represented by the Bayard-Clement, Astra, Zodiac, and the Government-built machines. Although the rigid type never has met with favour in France, there is yet a solitary example of this system of construction — the Spiess, which is 460 feet in length by 47 feet in diameter and has a displacement of 20 tons. The semi-rigid craft are represented by the Lebaudy type, the largest of which measures 293 feet in length by 51 feet in diameter, and has a displacement of 10 tons.
One may feel disposed to wonder why the French should be apparently backward in this form of aerial craft, but this may be explained by the fact that the era of experiment had not been concluded at the time war was declared, with the result that it has been somewhat difficult to determine which type would meet the military requirements of the country to the best advantage. Moreover, the French military authorities evinced a certain disposition to relegate the dirigible to a minor position, con- vinced that it had been superseded by the heavier- than-air machine. Taken on the whole, the French airship fleet is inferior to the German in point of speed, if not numerically, but this deficiency is more than counterbalanced by the skill and ability of the men manning their craft, who certainly are superior to their contemporaries in Germany, combined with the proved character of such craft as are in service.
BRITISH AIRSHIPS 51
The same criticism may be said to apply to Great Britain. That country was backward in matters pertaining to the airship, because its experiments were carried out spasmodically while dependence was reposed somewhat too much upon foreign effort. The British airships are small and of low speed comparatively speaking. Here again it was the advance of the aeroplane which was responsible for the manifestation of a somewhat indifferent if not lethargic feeling towards the airship. Undoubtedly the experiments carried out in Great Britain were somewhat disappointing. The one and only attempt to out-Zeppehn the ZeppeHn resulted in disaster to the craft before she took to the air, while the smaller craft carried out upon far less ambitious lines were not inspiritingly successful. Latterly the non-rigid system has been embraced exclusively, the craft being virtually mechanically driven balloons. They have proved efiicient and reliable so far as they go, but it is the personal element in this instance also which has contributed so materially to any successes achieved with them.
But although Great Britain and France apparently lagged behind the Germans, appreciable enterprise was manifested in another direction. The airship was not absolutely abandoned : vigilance was main- tained for a superior type of craft. It was an instance of weighing the advantages against the disadvantages of the existing types and then evolving for a design which should possess the former without
E 2
52 AEROPLANES AND DIRIGIBLES
any of the latter. This end appears to be achieved with the Astra type of dirigible, the story of the development of which offers an interesting chapter in the annals of aeronautics.
In all lighter-than-air machines the resistance to the air offered by the suspension ropes is consider- able, and the reduction of this resistance has proved one of the most perplexing problems in the evolution of the dirigible. The air is broken up in such a manner by the ropes that it is converted into a brake or drag with the inevitable result that the speed undergoes a severe diminution. A full-rigged air- ship such as the Parseval, for instance, may present a picturesque appearance, but it is severely un- scientific, inasmi^ph as if it were possible to eliminate or to reduce the air-resistance offered by the ropes, the speed efficiency might be raised by some sixty per cent, and that without any augmentation of the propelling effort. As a matter of fact Zeppelin solved this vexatious problem unconsciously. In his monster craft the resistance to the air is re- duced to a remarkable degree, which explains why these vessels, despite all their other defects, are able to show such a turn of speed.
It was this feature of the ZeppeHn which induced Great Britain to build the May-fly and which likewise induced the French Government to stimu- late dirigible design and construction among native manufacturers, at the same time, however, insisting that such craft should be equal at least in speed to
SENOR TORRES 53
the Zeppelins. The response to this invitation was the Spiess, which with its speed of 45 miles per hour ranked, until 1914, as one of the fastest dirigibles in the French service.
In the meantime a Spanish engineer, Sen or Torres, had been quietly working out a new idea. He realised the shortcomings of the prevailing types of airships some eleven years ago, and unostenta- tiously and painstakingly set out to eliminate them by the perfection of a new type of craft. He per- fected his idea, which was certainly novel, and then sought the assistance of the Spanish Government. But his fatherland was not adapted to the prosecution of the project. He strove to induce the authorities to permit even a small vessel to be built, but in vain. He then approached the French Astra Company. His ambition was to build a vessel as large as the current Zeppelin, merely to emphasise the value of his improvement upon a sufficiently large scale, and to enable comparative data concerning the two designs to be obtained. But the bogey of expense at first proved insuperable. However, the French company, decided to give the invention a trial, and to this end a small " vedette " of about 53,000 cubic feet displacement was built.
Although an unpretentious little vessel, it certainly served to emphasise the importance of the Torres idea. It was pitted against the " Colonel Renard," the finest ship at that time in the French aerial service, which had proved the fastest airship in
54 AEROPLANES AND DIRIGIBLES
commission, and which also was a product of the Astra Company. But this fine craft was completely outclassed by the puny Astra-Torres.
The builders and the inventor were now addition- ally anxious to illustrate more emphatically the features of this design and to build a far larger vessel. The opportunity was offered by the British Government, which had been following the experi- ments with the small Astra-Torres in France. An order was given for a vessel of 282,500 cubic feet displacement ; in this instance it was ranged against another formidable rival — the Parse val. But the latter also failed to hold its own against the Spanish invention, inasmuch as the Astra-Torres built for the British authorities exceeded a speed of 50 miles per hour in the official tests. This vessel is still doing valuable duty, being attached to the British air-service in France.
The achievements of the British vessel were not lost upon the French Government, which forthwith placed an order for a huge vessel of 812,200 cubic feet capacity, equipped with motors developing 1,000 horse-power, which it was confidently expected would enable a speed of 60 miles per hour to be attained. Thus France would be able to meet the Germans upon fairly level terms, inasmuch as the speed of the latest Zeppelins does not exceed 60 miles per hour. So confident were the authorities that a second order for an even larger vessel was placed before the first large craft was completed.
t : i\. ' ■'■
• ,* a ' ••*
V.' ■: }■<):''' y-'
sAji*'i«?-"M^
<i ♦ u-
THE ASTRA-TORRES AIRSHIP 55
This latter vessel is larger than any Zeppelin yet built, seeing that it displaces 38 tons, and is fitted with motors developing 1,000 horse-power. It has recently been completed, and although the results of the trials, as well as the dimensions of the craft have not been published, it is well known that the speed has exceeded 60 miles per hour, so that France now possesses the speediest dirigible in the world. The Torres invention has been described as wonderful, scientifically perfect and extremely simple. The vessel belongs to the non-rigid class, but the whole of the suspension system is placed within the gas-bag, so that the air-resistance offered by ropes is virtually eliminated in its entirety, for the simple reason that practically no ropes are placed outside the envelope. The general principle of design may be gathered from the accompanying diagram (Fig. 6). It is as if three sausage-shaped balloons were disposed pyramidally — two lying side by side with one super-imposed, with the bags connected at the points where the circular sections come into contact. Thus the external appearance of the envelope is decidedly unusual, comprising three symmetrical ridges. At the points where the three bags come into contact cloth bands are stretched across the arcs, thereby forming a cord. The suspension system is attached to the upper corners of the inverted triangle thus formed, and converges in straight lines through the gas space. The bracing terminates in collecting rings from which a short
S6 AEROPLANES AND DIRIGIBLES
vertical cable extends downwards through a special accordion sleeve to pass through the lower wall of the envelope. These sleeves are of special design, the idea being to permit the gas to escape under pressure arising from expansion and at the same
Fig. 6. — Section through Torres Type of Dirigible SHOWING Form of Design and Construction.
A, A, A, envelope ; B, B, B, cloth bands ; C, C, suspension ropes.
time to provide ample play for the cable which is necessary in a flexible airship.
This cable emerges from the envelope only at the point or points where the car or cars is or are placed.
THE ASTRA-TORRES AIRSHIP 57
In the British airship of this type there is only one car, but the larger French vessels are equipped with two cars placed tandem- wise. The vertical cable, after extending downwards a certain distance, is divided, one rope being attached to one, and the second to the other side of the car. The two-bladed propellers are disposed on either side of the car, in each of which a 500 horse-power motor is placed.
The Astra-Torres type of dirigible may be said to represent the latest expression in airship design and construction. The invention has given complete satisfaction, and has proved strikingly successful. The French Government has completed arrange- ments for the acquisition of larger and more power- ful vessels of this design, being now in the position to contest every step that is made by Germany in this field. The type has also been embraced by the Russian military authorities. The Astra-Torres airship has a rakish appearance, and although the lines of the gas-bag are admitted to increase frictional resistance, this is regarded as a minor defect, especially when the many advantages of the invention are taken into consideration.
CHAPTER V
Germany's aerial dreadnought fleet
Although Germany, as compared with France, was relatively slow to recognise the immense possibilities of aircraft, particularly dirigibles, in the military sense, once the Zeppelin had received the well-wishes of the Emperor William, Teuton activities were so pronounced as to enable the leeway to be made up within a very short while. While the Zeppelin commanded the greatest attention owing to the interesting co-operation of the German Emperor, the other types met with official and royal recognition and encouragement as already mentioned. France, which had held premier position in regard to the aerial fleet of dirigibles for so long, was com- pletely out-classed, not only in dimensions but also in speed, as well as radius of action and strategical distribution of the aerial forces.
The German nation forged ahead at a great pace and was able to establish a distinct supremacy, at least on paper. In the light of recent events it is apparent that the German military authorities
58
THE FRENCH AIR FLEET 59
realised that the dawn of " The Day " was approach- ing rapidly, and that it behoved them to be as fully prepared in the air as upon the land. It was immaterial that the Zeppelin was the synonym for disaster. By standardisation its cost could be reduced while construction could be expedited. Furthermore, when the matter was regarded in its broadest aspect, the fact was appreciated that forty Zeppelins could be built at the cost of one super-Dreadnought, so that adequate allowance could be made for accidents now and then, since a Zeppelin catastrophe, no matter how complete, it may be, is regarded by the Teuton as a mere incident inseparable from progressive development. At the beginning of the year 19 14 France relied upon being strengthened by a round dozen new dirigibles. Seven of these were to be of 20,000 cubic metres' capacity and possessed of a speed of 47 miles per hour. While the existing fleet was numerically strong, this strength was more apparent than real, for the simple reason that a large number of craft were in dry-dock undergoing repair or overhaul while many of the units were merely under test and could not be regarded therefore as in the effective fleet. True, there were a certain number of private craft which were liable to be commandeered when the occasion arose, but they could not be considered as decided acquisitions for the simple reason that many were purely experimental units.
Aerial vessels, like their consorts upon the water.
6o AEROPLANES AND DIRIGIBLES
have been divided into distinctive classes. Thus there are the aerial cruisers comprising vessels exceeding 282,000 cubic feet in capacity ; scouts which include those varying between 176,600 and 282,000 cubic feet capacity ; and vedettes, which take in all the small or mosquito craft. At the end of 1913, France possessed only four of the first -named craft in actual commission and thus immediately available for war, these being the Adjutant Vincenot, Adjutant Reau, Dupuy de Lome, and the Transae'rien. The first three are of 197,800 cubic feet. All, however, were privately owned.
On the other hand, Germany had no fewer than ten huge vessels, ranging from 353,000 to 776,900 cubic feet capacity, three of which, the Victoria Luise, Suchard, and Hansa, though owned privately, were immediately available for war. Of these the largest was the Zeppelin naval vessel " L-I " 525 feet in length, by 50 feet diameter, of 776,900 cubic feet capacity, equipped with engines developing 510 horse-power, and with a speed of 51-8 miles per hour.
At the end of 1913 the effective aerial fleet of Germany comprised twenty large craft, so far in advance of the French aerial cruisers as to be worthy of the name bestowed upon them — 'Aerial Dreadnoughts.'' This merely represented the fleet available for immediate use and did not include the four gigantic Suchard-Schiitte craft, each of
ZEPPELIN HARBOURS 6i
847,500 cubic feet, which were under construction, and which were being hurried forward to come into commission early in 1914.
But the most interesting factor, apart from the possession of such a huge fleet of dirigible air-craft, was their distribution at strategical points throughout the Empire as if in readiness for the coming combat. They were literally dotted about the country. Adequate harbouring facilities had been provided at Konigsberg, Berlin, Posen, Breslau, Kiel, Hamburg, Wilhelmshaven, Dlisseldorf, Cologne, Frankfort, Metz, Mannheim, Strasburg, and other places, with elaborate headquarters, of course, at Friedrichshafen upon Lake Constance. The Zeppelin workshops, harbouring facilities, and testing grounds at the latter point had undergone complete re- modelling, while tools of the latest type had been provided to facilitate the rapid construction and overhaul of the monster Zeppelin dirigibles. Nothing had been left to chance ; not an item was perfunc- torily completed. The whole organisation was per- fect, both in equipment and operation. Each of the above stations possessed provision for an aerial Dreadnought as well as one or more aerial cruisers, in addition to scouts or vedettes.
Upon the outbreak of hostilities Germany's dirigible fleet was in a condition of complete pre- paredness, was better organised, and better equipped than that of any of her rivals. At the same time it constituted more of a paper than a fighting array for
62 AEROPLANES AND DIRIGIBLES
reasons which I will explain later. But there was another point which had escaped general observa- tion. Standardisation of parts and the installation of the desired machinery had accomplished one greatly desired end — the construction of new craft had been accelerated. Before the war an interesting experi- ment was carried out to determine how speedily a vessel could be built. The result proved that a dirigible of the most powerful type could be com- pleted within eight weeks and forthwith the various constructional establishments were brought into line so as to maintain this rate of building.
The growth of the Zeppelin, although built upon disaster, has been amazing. The craft of 1906 had a capacity of 430,000 cubic feet and a speed of 36 miles per hour. In 191 1 the creator of this type launched a huge craft having a capacity of 627,000 cubic feet. In the meantime speed had likewise been augmented by the use of more powerful motors until 52 miles an hour was attained. But this by no means represented the limit. The foregoing vessels had been designed for land service purely and simply, but now the German authorities demanded similar craft for naval use, possessed of high speed and greater radius of action. Count Zeppelin rose to the occasion, and on October 7th, 1 91 2, launched at Friedrichshafen the monster craft " L-I," 525 feet in length, 50 feet in diameter, of 776,900 cubic feet capacity, a displacement of 22 tons and equipped with three sets of motors
NAVAL AIR-CRAFT 63
aggregating more than 500 horse-power, and capable of imparting a speed of 52 miles per hour.
The appearance of this craft was hailed with intense delight by the German nation, while the naval department considered her to be a wonderful acquisition, especially after the searching relia- bility trial. In charge of Count Zeppelin and manned by a crew of 22 officers and men together with nearly three tons of fuel — the fuel capacity conveys some idea of her possible radius of action — she travelled from Friedrichshafen to Johannisthal in 32 hours. On this remarkable journey another point was es- tablished which was of far-reaching significance. The vessel was equipped with wireless telegraphy and therewith she kept in touch with the earth below throughout the journey, dropping and picking up wireless stations as she progressed with complete facility. This was a distinct achievement, inasmuch as the vessel having been constructed especially for naval operations she would be able to keep in touch with the warships below, guiding them unerringly during their movement.
The cross-country trip having proved so completely successful the authorities were induced to believe that travelling over water would be equally satis- factory. Accordingly the " L-I " was dispatched to the island of Heligoland, the intention being to participate in naval manoeuvres in order to provide some reliable data as to the value of these craft operating in conjunction with warships. But in
64 AEROPLANES AND DIRIGIBLES
these tests German ambition and pride received a check. The huge Zeppehn was manoeuvring over the North Sea within easy reach of HeHgoland, when she was caught by one of those sudden storms peculiar to that stretch of salt water. In a moment she was stricken helpless ; her motive power was overwhelmed by the blind forces of Nature. The wind caught her as it would a soap-bubble and hurled her into the sea, precipitating the most disastrous calamity in the annals of aeronautics, since not only was the ship lost, but fifteen of her crew of 22 officers and men were drowned.
The catastrophe created consternation in German aeronautical circles. A searching inquiry was held to explain the disaster, but as usual it failed to yield much material information. It is a curious cir- cumstance, but every successive Zeppelin disaster, and their number is legion, has been attributable to a new cause. In this instance the accident was additionally disturbing, inasmuch as the ship had been flying across country continuously for about twelve months and had covered more miles than any preceding craft of her type. No scientific explan- ation for the disaster was forthcoming, but the commander of the vessel, who sank with his ship, had previously ventured his personal opinion that the vessel was over-loaded to meet the calls of ambition, was by no means seaworthy, and that sooner or later she would be caught by a heavy broadside wind and rendered helpless, or that she
ZEPPELIN "L-ir' 65
would make a headlong dive to destruction. It is a significant fact that he never had any faith in the airship, at least for sea duty, though in response to official command he carried out his duties faithfully and with a blind resignation to Fate.
Meantime, owing to the success of the " L-I " in cross-country operations, another and more powerful craft, the " L-II " had been taken in hand, and this was constructed also for naval use. While shorter than her consort, being only 487 feet over- all, this vessel had a greater beam — 55 feet. This latter increase was decided because it was con- ceded to be an easier matter to provide for greater beam than enhanced length in the existing air-ship harbours. The ''L-II " displaced 27 tons — five tons in excess of her predecessor. In this vessel many innovations were introduced, such as the provision of the passage-way connecting the cars within the hull, instead of outside the latter as had hitherto been the practice, while the three cars were placed more closely together than formerly. The motors were of an improved type, giving an aggregate output of 900 horse-power, and were divided into four separate units, housed in two engine-rooms, the front car being a replica in every detail of the navigating bridge of a warship.
This vessel was regarded as a distinct improve- ment upon the " L-I," although the latter could boast some great achievements. But her glory was short-lived. In the course of the Government
F
66 AEROPLANES AND DIRIGIBLES
trials, while some 900 feet aloft, the huge vessel suddenly exploded and was burned in the air, a mass of broken and twisted metal-work falling to the ground. Of the 28 officers and men, including members of the Admiralty Board who were con- ducting the official trials, all but one were killed outright, and the solitary exception was so terribly burned as to survive the fall for only a few hours.
The accident was remarkable and demonstrated very convincingly that although Count Zeppelin ap- parently had made huge strides in aerial navigation through the passage of years, yet in reality he had made no progress at all. He committed the identical error that characterised the effort of Severo Pax ten years previously, and the disaster was directly attributable to the self-same cause as that which overwhelmed the Severo airship. The gas, escaping from the balloons housed in the hull, collected in the confined passage-way communicating with the cars, came into contact with a naked light, possibly the exhaust from the motors, and instantly de- tonated with terrific force, blowing the airship to fragments and setting fire to all the inflammable materials.
In this airship Zeppelin committed an unpardon- able blunder. He had ignored the factor of " in- ternal safety," and had deliberately flown in the face of the official rule which had been laid down in France after the Severo disaster, which absolutely forbade the inclusion of such confined spaces as
ZEPPELIN IV AT LUNEVILLE 67
Zeppelin had incorporated. This catastrophe coming so closely as it did upon the preceding disaster to the pride of the German aerial fleet somewhat shook public confidence in these craft, while aeronautical authorities of other countries described the Zeppelin more vehemently than ever as a " mechanical monstrosity " and a " scientific curiosity."
The Zeppehn has come to be feared in a general manner, but this result is due rather to stories sedulously circulated, and which -may be easily traced to Teutonic sources. Very few data of a reli- able character have been allowed to filter through official circles. We have been told somewhat verbosely of what it can accomplish and of its high degree of efficiency and speed. But can credence be placed in these statements ?
When Zeppelin IV. made its unexpected descent at Luneville, and was promptly seized by the French authorities, the German War Office evinced distinct signs of uneasiness. The reason was speedily forth- coming. The captain of the craft which had been captured forgot to destroy his log and other records of data concerning the vessel which had been scientifically collected during the journey. All this information fell into the hands of the French military department, and it proved a wondrous revelation. It enabled the French to value the Zeppelin at its true worth, which was by no means comparable to the estimate based on reports skil- fully circulated for the benefit of the world at large.
F 2
68 AEROPLANES AND DIRIGIBLES
Recently the French mihtary department per- mitted the results of their expert official examination to be made pubUc. From close investigation of the log-book and the diagrams which had been prepared, it was found that the maximum speed attained by Zeppelin IV. during this momentous flight was only 45 miles per hour ! It was ascertained, moreover, that the load was 10,560 pounds, and the ascensional effort 45,100 pounds. The fuel consumption had averaged 297 pounds per hour, while the fuel tanks carried sufficient for a flight of about seven hours. The airship had attained a maximum height of about 6,230 feet, to reach which 6,600 pounds of ballast had to be discarded. Moreover, it was proved that a Zeppelin, if travelling under military conditions with full armament and ammunition aboard, could carry sufficient fuel for only ten hours at the utmost, during which, if the slightest head-wind prevailed, it could not cover more than 340 miles on the one fuel charge.
This information has certainly proved a revelation and has contributed to the indifference with which the Parisians regard a Zeppelin raid. At the out- break of war the Zeppelin station nearest to Paris was at Metz, but to make the raid from that point the airship was forced to cover a round 500 miles. It is scarcely to be supposed that perfectly calm weather would prevail during the whole period of the flight, so that a raid would be attended by con-
I
CAPTURE OF ZEPPELIN IV 69
siderable risk. That this handicap was recognised in German mihtary circles is borne out by the fact that a temporary Zeppelin hangar was estab- lished at a point considerably nearer the French capital, for the purpose of enabling a raid to be carried out with a greater possibility of success.
The capture of Zeppelin IV. revealed another important fact. The critical flying height of the airship is between 3,300 and 4,000 feet. To attempt a raid at such an altitude would be to court certain disaster, inasmuch as the vessel would have to run the gauntlet of the whole of the French artillery, which it is admitted has a maximum range exceeding the flying altitude of the Zeppelin. That the above calculation is within reason is supported by the statements of Count Zeppelin himself, who has declared that his airships are useless at a height exceeding 5,000 feet. Confirmatory evidence upon this point is offered by the raid upon the British East Coast towns, when it is stated that the aircraft were manoeuvring at a height not exceeding 2,000 feet.
CHAPTER VI
THE MILITARY VALUE OF GERMANY'S AERIAL FLEET
Although the Zeppelin undoubtedly has been over-rated by the forces to which it is attached, at the same time it must not be under-estimated by its detractors. Larger and more powerful vessels of this type have been, and still are being, con- structed, culminating, so far as is known, in the " L-5," which is stated to have a capacity of about 1,000,000 cubic feet, and to possess an average speed of 65 miles per hour.
While it is generally maintained that the Zeppelins will prove formidable in attack, greater reliance is being placed upon the demoralising or terrifying effect which they are able to exercise. Owing to the fact that from 3 to 5 tons of fuel — say 900 to 1,500 gallons of gasoline or petrol — can be carried aboard, giving them a wide radius of action, it is doubtful whether they could travel from Cologne to London and back upon a single fuel charge, since such a raid would entail a journey of about 600
NOCTURNAL RAIDS 71
miles. The latest types of this craft are said to possess a high ascensional speed, which offers a distinct protection against aeroplane attack. Accord- ing to such official information as has been vouch- safed, a Zeppelin, when hard pressed, is able to rise vertically 3,500 feet in about three minutes. This is far in excess of the ascensional speed of even the speediest aeroplane. Of course, the penalty for such a factor has to be paid : the loss of gas is appreciable and may lead to the craft's ultimate undoing. At the same time, however, it is able to maintain the superior position as compared with the aeroplane for a considerable period : the upper reaches of the air are its sanctuary.
Nor must the nocturnal activities of the Zeppelin be overlooked. So far as night operations by these vessels are concerned, little has leaked out, so that the possibilities of the airship in this direction are still somewhat hypothetical. The fact remains, how- ever, that it is night movements which perhaps are the most to be dreaded by the enemy. According to official German sources of information the latest types of Zeppelins are engined by " noiseless " motors. There is nothing remarkable in this feature, since the modern motor-car virtually answers to this description, although in this instance quietness is obtained for the most part by recourse to the sleeve- valve engine. Still, the ordinary Otto-cycle internal combustion engine can be rendered almost silent by the utilisation of adequate muffling devices,
72 AEROPLANES AND DIRIGIBLES
which, in the ZeppeHn, are more possible of in- corporation than in the aeroplane, because the extra weight imposed by this acquisition is a minor con- sideration in comparison with the lifting power of the vessel.
Night operations, however, have not proved eminently successful. The very darkness which protects the aerial prowler also serves a similar purpose in connection with its prey. But aerial operations under the cover of darkness are guided not so much by the glare of lights from below as betrayal by sound. The difference between villages and cities may be distinguished from aloft, say at 1,500 to 3,000 feet, by the hum which life and movement emit, and this is the best guide to the aerial scout or battleship. The German authorities have made a special study of this peculiar problem, and have conducted innumerable tests upon the darkest nights, when even the sheen of the moon has been unavailable, for the express purpose of training the aerial navigators to discover their position from the different sounds reaching them from below. In other words, the corsair in the skies depends more upon compass and sound than upon compass and vision when operating after dark. The searchlights with which the Zeppelins are equipped are provided merely for illuminating a supposed position. They are not brought into service until the navigator concludes that he has arrived above the desired point : the ray of light
AIRSHIP "V-i'' 73
which is then projected is merely to assist the crew in the discharge of the missiles of destruction.
The Zeppelin, however, owing to its speed, both in the horizontal and vertical planes, is essentially a unit for daylight operations. The other airships which Germany possesses, and which for the most part are of the non-rigid type, are condemned to daylight operations from the character of their design. Owing to their low speeds they may be dismissed as impossible aerial vessels for hazardous work and are not regarded by the German authorities as all-round airships of war.
Craft of the air are judged in Germany from the one standard only. This may be a Teutonic failing, but it is quite in keeping with the Teutonic spirit of militarism. Commercialism is a secondary factor. To the. German Emperor an airship is much what a new manufacturing process or machine is to the American. Whereas the latter asks, " How much will it save me on the dollar ? " to the War Lord of Germany — and an airship notwithstanding its other recommendatory features is judged solely from this standpoint — the question is : " What are its military qualifications ? "
When the semi-rigid airship " V-i " was brought before the notice of the German military department the pressing point concerning its military recom- mendations arose at once. The inventor had fore- seen this issue and was optimistic. Thereupon the authorities asked if the inventor were prepared
74 AEROPLANES AND DIRIGIBLES
to justify his claims. The retort was positive. Forthwith the Junkers decided to submit it to the test.
This ship is of quite a distinctive type. It is an aerial cruiser, and the inventor claims that it com- bines all the essential qualifications of the Zeppelin and of the competitors of the latter, in addition to the advantage of being capable of dissection, trans- portation in parts, and rapid re-erection at any desired spot. The length of the vessel is about 270 feet ; maximum diameter approximately 42 feet, and capacity about 300,000 cubic feet. The outstanding feature is a rigid keel-frame forming a covered passage way below the envelope or gas-bag> combined with easy access to all parts of the craft while under way, together with an artificial stiffening which dispenses with the necessity of attaching any additional cars. The frame is so designed that the load, as well as the ballast and fuel tanks, may be distributed as desired, and at the same time it ensures an advantageous disposition of the steering mechanism, far removed from the centre of rotation at the stern, without any overloading of the latter.
The lifting part of the airship comprises a single gas bag fitted with two ballonets provided to ensure the requisite gas-tension in the main envelope, while at the same time permitting, in times of emer- gency, a rapid change of altitude. Self-contained blowers contribute to the preservation of the shape of the envelope, the blowers and the ballonets being
ZEPPELINS TO INVADE ENGLAND 75
under the control of the pilot. Planes resembling Venetian blinds facilitate vertical steering, while the suspension of the keel is carried out in such a manner as to secure uniformity of weight upon the gas bag. The propelling power comprises two sets of internal combustion engines, each developing 130 horse-power, the transmission being through rubber belting. The propellers, built of wood, make 350 revolutions per minute, and are set as closely as possible to the centre of resistance.
But the most salient characteristic of this machine is its portability. It can be dismantled and trans- ported by wagons to any desired spot, the suspension frame being constructed in units, each of which is sufficiently small to be accommodated in an or- dinary vehicle. Upon arrival the parts may be put together speedily and easily. The authorities sub- mitted the airship to exacting trials and were so impressed by its characteristics and the claims of the inventor that undoubtedly it will be brought into service during the present crisis.
At the same time the whole faith of the German military staff so far as airship operations are con- cerned, is pinned to the Zeppelin. Notwithstanding its many drawbacks it is the vessel which will be used for the invasion of Great Britain. Even the harbour question, which is admitted to be somewhat acute, has been solved to a certain degree. At stra- tegical points permanent harbours or airship sheds have been established. Seeing that the airships
76 AEROPLANES AND DIRIGIBLES
demand considerable skill in docking and undocking, and that it is impossible to achieve these operations against the wind, swinging sheds have been adopted.
On water the practice is to anchor a floating harbour at one end, leaving the structure to swing round with the wind. But on dry land such a dock is impossible. Accordingly turn-table sheds have been adopted. The shed is mounted upon a double turn-table, there being two circular tracks, the one near the centre of the shed and the other towards its extremities. The shed is mounted upon a centre pivot and wheels engaged with these inner and outer tracks. In this manner the shed may be swung round to the most favourable point of the compass according to the wind.
In the field, however, such practices are impossible, and the issue in this connection has been overcome by recourse to what may be termed portable harbours. They resemble the tents of peripatetic circuses and travelling exhibitions. There is a network of vertical steel members which may be set with facility and speed and which are stayed by means of wire guys. At the top of the outer vertical posts pulleys are provided whereby the outer skin or canvas forming the walls may be hauled into position, while at the apex of the roof further pulleys ensure the proper placing of the roofing. The airship is able to enter or leave from either end according to conditions. The material is fire- proofed as a precautionary measure, but at the same
[A IJieri
Belgian Mechanics Repairing an Aeroplane Engine at the Aviation Base of the Allies in the North of France.
BRITISH RAIDS ON GERMANY 77
time the modern aerial bomb is able to penetrate the roofing without any difficulty and to explode against the airship anchored within.
The one great objection to the Zeppelin harbour is the huge target it offers to hostile attack, which, in the event of a vessel being moored within, is inevitably serious. Thus, for instance, upon the occasion of the air raids conducted by Lieutenant Collet and of Squadron Commander Briggs and his colleagues at Diisseldorf and Friedrichshafen re- spectively, little difficulty was experienced in destroying the airships riding at anchor. The target offered by the shed is so extensive that it would be scarcely possible for a flying enemy to miss it. A bomb dropped from a reasonable height, say 500 feet, would be almost certain to strike some part of the building, and a Zeppelin is an easy vessel to destroy. The firing of one balloon is sufficient to detonate the whole, for the simple reason that hydrogen gas is continuously oozing through the bags in which it is contained. Ac- cording to a recent statement the Germans are said to be utilising an inert or non-inflammable gas, equal in lifting power to hydrogen, for the inflation of mihtary craft, but scientific thought does not entertain this statement with any degree of serious- ness. No gas as fight as hydrogen and non-explosive is known to commerce.
Will Germany invade Great Britain by air ? This is the absorbing topic of the moment — one
78 AEROPLANES AND DIRIGIBLES
which has created intense interest and a certain feeling of alarm among the timorous. Although sporadic raids are considered to be possible and likely to be carried out with a varying measure of success — ^such as that made upon the British East Coast — eminent authorities ridicule an invasion in force. The risk would be enormous, although there is no doubt that Germany, which has always maintained that an invasion of this character will be made, will be compelled to essay such a task, in order to satisfy public opinion, and to justify official statements. It is a moot point, however, whether the invaders ever will succeed in making good their escape, unless Nature proves exception- ally kind.
The situation is best summed up in the unbiassed report of General George P. Scriven, Chief Signal Officer of the United States Army to the U.S. Secre- tary of War. In this report, which deals exhaustively with the history, construction and achievements of airships, such an invasion is described as fantastic and impracticable. Writing on November loth, 1914, the officer declares that " he is not prepared to recommend the American Army to take up seriously the question of constructing dirigibles, as they are not worth their cost as offensive machines, while for reconnaissance or defence they are of far less value than aeroplanes." In his words, " Dirigibles are seemingly useless in defence against the aeroplane or gun-fire."
DISABILITIES 79
In order to be able to make an invasion in force upon Great Britain's cities extremely favourable weather must prevail, and the treacherous nature of the weather conditions of the North Sea are known fully well both to British and Teuton navigators. Seeing that the majority of the Zeppelin pilots are drawn from the Navy and mercantile marine, and thus are conversant with the peculiarities and char- acteristics of this stretch of salt water, it is only logical to suppose that their knowledge will exert a powerful influence in any such decision, the re- commendations of the meteorological savants not- withstanding.
When the Zeppelin pride of the German Navy " L-I " was hurled to destruction by a typical North Sea squall, Captain Blew of the Victoria Luise, a Zeppelin with many great achievements to her credit, whose navigator was formerly in the Navy, and thus is familiar with the whole issue, explained that this atmospheric liveliness of the North Sea prevails for the most part in the latitude of Norway, but that it frequently extends as far south as the gate of the Channel. He related furthermore that the rain squalls are of tropical violence, while the vertical thrusts of air are such that no dirigible as yet constructed could ever hope to live in them. Under such conditions, he continued, the gas is certain to cool intensely, and the hull must then become waterlogged, not to mention the downward thrust of the rain. Under such conditions buoyancy must
8o AEROPLANES AND DIRIGIBLES
be imperilled to such a degree as to demand the jettisoning of every piece of ballast, fuel and other removable weight, including even the steadying and vertical planes. When this has been done, he pointed out, nothing is left with which to combat the upward vertical thrusts of the air. To attempt to run before the wind is to court positive disaster, as the wind is certain to gain the mastery. Once the airship loses steering way and is rendered un- controllable it becomes the sport of the forces of Nature, with the result that destruction is merely a matter of minutes, or even seconds.
Every navigator who knows the North Sea will support these conclusions. Squalls and blizzards in winter, and thunderstorms in summer, rise with startling suddenness and rage with terrific destructive fury. Such conditions must react against the attempt of an aerial invasion in force, unless it be made in the character of the last throw by a des- perate gambler, with good fortune favouring the dash to a certain degree. But lesser and more insignificant Zeppelin raids are likely to be some- what frequent, and to be made at every favourable climatic opportunity.
CHAPTER VII
AEROPLANES OF WAR
Owing to the fertility of inventors and the resul- tant multiplicity of designs it is impossible to describe every type of heavier-than-air machine which has been submitted to the exacting requirements of mihtary duty. The variety is infinite and the salient fact has already been established that many of the models which have proved reliable and efficient under normal conditions are unsuited to mihtary operations. The early days of the war enabled those of doubtful value to be eliminated, the result being that those machines which are now in use represent the survival of the fittest. Exper- ience has furthermore emphasised the necessity of reducing the number of types to the absolute minimum. This weeding-out process is being con- tinued and there is no doubt that by the time the war is concluded the number of approved types of aeroplanes of mihtary value will have been reduced to a score or less. The inconveniences and disad-
8t Q
82 AEROPLANES AND DIRIGIBLES
vantages arising from the utilisation of a wide variety of different types are manifold, the greatest being the necessity of carrying a varied assortment of spare parts, and confusion in the repair and over- hauling shops.
The methodical Teuton was the first to grasp the significance of these drawbacks ; he has accord- ingly carried standardisation to a high degree of efficiency, as is shown in another chapter. At a later date France appreciated the wisdom of the German practice, and within a short time after the outbreak of hostilities promptly ruled out certain types of machines which were regarded as unsuit- able. In this instance the process of elimination created considerable surprise, inasmuch as it in- volved an embargo on the use of certain machines, which under peace conditions had achieved an international reputation, and were held to represent the finest expression of aeronautical science in France as far as aeroplane developments are concerned.
Possibly the German machine which is most famihar, by name, to the general public is the Taube, or, as it is sometimes called, the Etrich monoplane, from the circumstance that it was evolved by the Austrian engineer Igo Etrich in collaboration with his colleague Wels. These two experimenters embarked on the study of dynamic flight contemporaneously with Maxim, Langley, Kress, and many other well-known pioneers, but
THE '^TAUBE' 83
it was not until 1908 that their first practical machine was completed. Its success was instan- taneous, many notable flights being placed to its credit, while some idea of the perfection of its design may be gathered from the fact that the machine of to-day is substantially identical with that used seven years ago, the alterations which have been effected meanwhile being merely modifications in minor details.
The design of this machine follows very closely the lines of a bird in flight — ^hence its colloquial description, " Taube," or " dove." Indeed the analogy to the bird is so close that the ribs of the frame resemble the feathers of a bird. The sup- porting plane is shaped in the manner of a bird's distended wing, and is tipped up at the rear ends to ensure stability. The tail also resembles that of a bird very closely.
This aeroplane, especially the latest type, is very speedy, and it has proved extremely reliable. It is very sharp in turning and extremely sensitive to its rudder, which renders it a first-class craft for reconnoitring duty. The latest machines are fitted with motors developing from 120 to 150 horse-power.
The '' Taube " commanded attention in Ger- many for the reason that it indicated the first departure from the adherence to the French designs which up to that time had been followed somewhat slavishly, owing to the absence of native initiative. The individuality of character revealed in the
G2
84 AEROPLANES AND DIRIGIBLES
" Taube " appealed to the German instinct, with the result that the machine achieved a greater reputation than might have been the case had it been pitted against other types of essentially Teutonic origin. The Taube was subsequently tested both in France and Great Britain, but failed to raise an equal degree of enthusiasm, owing to the manifestation of certain defects which marred its utility. This practical experience tended to prove that the Taube, like the Zeppelin, possessed a local reputation somewhat of the paper type. The Germans, however, were by no means disappointed by such adverse criticism, but promptly set to work to eliminate defects with a view to securing an all-round improvement.
The most successful of these endeavours is repre- sented in the Taube-Rumpler aeroplane, which may be described as an improved edition of Etrich's original idea. As a matter of fact the modifications were of so slight, though important, a character that many machines generically described as " Taubes " are in reality Rumplers, but the differ- ence is beyond detection by the ordinary and un- practised observer.
In the Rumpler machine the wings, like those of the Taube, assume broadly the form and shape of those of the pigeon or dove in flight. The early Rumpler machines suffered from sluggish control, but in the later types this defect has been overcome. In the early models the wings were flexible, but in
¥
THE -GOTHA" AND -ALBATROSS" 85
the present craft they are rigid, although fitted with tips or ailerons. The supporting truss beneath the wings, which was such an outstanding feature of its prototype, has been dispensed with, the usual I-beam longitudinals being used in its stead. The latest machines fitted with 100-120 horse-power Mercedes motors have a fine turn of speed, possess an enhanced ascensional effort, and are far simpler to control.
Other German machines which are used in the military service are the Gotha and the Albatross. The former is a monoplane, and here again the influence of Etrich upon German aeroplane develop- ments is strongly manifested, the shape of the bird's wing being retained. In the Gotha the truss which Etrich introduced is a prominent characteristic. The Albatross is a biplane, but this craft has proved to be somewhat slow and may be said to be confined to what might be described as the heavier aerial military duties, where great endurance and relia- bility are essential. As the war proceeds, doubtless Teuton ingenuity will be responsible for the appear- ance of new types, as well as certain modifications in the detail construction of the existing machines, but there is every indication that the broad lines of Etrich's conception will be retained in all mono- planes.
There is one point in which Germany has excelled. Wood is not employed in the construction of these heavier-than-air craft. Steel and the lighter tough
86 AEROPLANES AND DIRIGIBLES
alloys are exclusively used. In this way the minimum of weight consistent with the maximum of strength policy is carried out. Moreover the manufacture of component parts is facilitated and accelerated to a remarkable degree by the use of metal, while the tasks of fitting and repairing are notably expedited by the practice of standardisation. Germany is also manifesting commendable enterprise in the perfection of light powerful motors for these dynamic machines. The latest types of explosion-motors range from loo to 150 horse-power ; the advantages of these are obvious.
Upon the outbreak of hostilities the French possessed an enormous number and variety of aeroplanes and this aerial fleet had been brought to a high standard of organisation. The aerial fleet is sub-divided into squadrons called " escadrilles/' each of which comprises six machines and pilots. These units are kept up to strength, wastage being made up from reserves, so as to maintain the re- quisite homogeneity.
But ere the war had been in progress many weeks an oflicial order was issued forbidding the employ- ment of the Bleriot, Deperdussin, Nieuport, and R.E.P. monoplanes. Those which received official approval included the Caudron, Henry, and Maurice Farman, Morane-Saulnier, and Voisin machines.
This drastic order came somewhat as a thunder- bolt, and the reason for the decree has not been satis- factorily revealed. Suffice to say that in one stroke
FRENCH TYPES 87
the efficiency and numerical strength of the French aerial navy were reduced very appreciably. For instance, it is stated that there were thirty escad- rilles of Bleriot monoplanes together with pilots at the front, in addition to thirty mixed escadrilles of the other prohibited types with their fliers. Moreover a round 33 escadrilles of all the various types were in reserve. The effect of the military order was to reduce the effective strength by no fewer than 558 aeroplanes.
Seeing that the French aerial force was placed at a great disadvantage numerically by this action, there seems to be ample justification for the hostile criticism which the decree of prohibition aroused in certain circles, especially when it is remembered that there was not an equal number of the accepted machines available to take the place of those which had been ruled out of court. One effect of this decree was to throw some 400 expert aviators upon the waiting list for the simple reason that machines were unavailable. Some of the best aviation skill and knowledge which France possesses were affected by the order. It is stated that accomplished aviators, such as V^drines, were unable to obtain machines.
It will be seen that the ultimate effect of the French military decree was to reduce the number of types to about four, each of which was allotted a specific duty. But whereas three different bi- planes are on the approved list there is only one monoplane — the Morane-Saulnier, This machine,
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however, has a great turn of speed, and it is also able to climb at a very fast pace. In these respects it is superior to the crack craft of Germany, so that time after time the latter have refused battle in the skies, and have hurried back to their lines.
The Morane-Saulnier is the French mosquito craft of the air and like the insect, it is avowedly aggressive. In fact, its duties are confined to the work of chasing and bringing down the enemy, for which work its high manoeuvring capacity is excellently adapted. Its aggressive armament comprises a mitrailleuse. Unfortunately, however, the factory responsible for the production of this machine is at present handicapped by the limitations of its manufacturing plant, which when pushed to the utmost extent cannot turn out more than about ten machines per week. No doubt this deficiency will be remedied as the war proceeds by extension of the works or by allotting orders to other establishments, but at the time of the decree the manufacturing capacity was scarcely sufficient to make good the wastage, which was somewhat heavy.
As far as biplanes are concerned the Caudron is the fastest in flight and is Ukewise extremely quick in manoeuvring. It is a very small machine and is extremely light, but the fact that it can climb at the rate of over 330 feet per minute is a distinct advantage in its favour. It supplements the Morane- Saulnier monoplane in the specific duty of the latter, while it is also employed for discovering the enemy's
RECONNAISSANCE 89
artillery and communicating the range of the latter to the French and British artillery. In this latter work it has played a very prominent part and to it is due in no small measure that deadly accuracy of the artillery of the Allies which has now become so famous. This applies especially to those tactics, where the field artillery dashes up to a position, discharges a number of rounds in rapid succession, or indulges in rafale firing, and then limbering up, rushes away before the enemy can reply.
As is well known the Farman biplanes possess high endurance qualities. They can remain aloft for many hours at a stretch and are remarkably reliable. Owing to these qualities they are utilised for prolonged and searching reconnoitring duties such as strategical reconnaissances as distinct from the hurried and tactical reconnaissances carried out by fleeter machines. While they are not so speedy as the monoplanes of the German military estabhsh- ment, endurance in this instance is preferable to pace. A thorough survey of the enemy's position over the whole of his military zone, which stretches back for a distance of 30 miles or so from the outer line of trenches, is of incalculable value to a com- mander who is contemplating any decisive move- ment or who is somewhat in doubt as to the precise character of his antagonist's tactics.
The French aerial fleet has been particularly active in its work of raiding hostile positions and submitting them to a fusillade of bombs from the
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clouds. The machine which is allotted this specific task is the Voisin biplane. This is due to the fact that this machine is able to carry a great weight. It was speedily discovered that in bomb-raids it is essential for an aeroplane to be able to carry a somewhat large supply of missiles, owing to the high percentage of misses which attends these operations. A raid by a machine capable of carrying only, say, half-a-dozen projectiles, is virtually a waste of fuel, and the endurance limitations of the fast machines reacts against their profitable use in this work. On the other hand, the fact that the Voisin machine is able to carry a large supply of bombs renders it an ideal craft for this purpose ; hence the official decision to confine it to this work. So far as the British efforts in aerial work are concerned there is no such display of rigid selection as characterises the practice of the French and Ger- man military authorities. Britain's position in the air has been extensively due to private enterprise, and this is still being encouraged. Moreover at the beginning of the war Britain was numerically far inferior both to her antagonist and to her ally. Consequently it was a wise move to encourage the private manufacture of machines which had already established their value. The consequence is that a variety of machines figure in the British aerial navy. Private initiative is excellently seconded by the Government manufacturing aeroplane fac- tory, while the training of pilots is likewise being
BRITISH TYPES 91
carried out upon a comprehensive scale. British manufacture may be divided into two broad classes — the production of aeroplanes and of waterplanes respectively. Although there is a diversity of types there is a conspicuous homogeneity for the most part, as was evidenced by the British raid carried out on February 11-12, when a fleet of 34 machines raided the various German miHtary centres established along the coast of Flanders.
Considerable secrecy has been displayed by the British Government concerning the types of machines that are being utilised, although ample evidence exists from the producing activity of the various establishments that all available types which have demonstrated their reliability and efficiency are being turned to useful purpose. The Avro and Sopwith warplanes with their very high speeds have proved remarkably successful.
So far as manufacturing is concerned the Royal Aerial Factory may be said to constitute the back- bone of the British aerial fleet. This factory fulfils various purposes. It is not only engaged in the manufacture of machines, and the development of aeroplanes for specific duties, but also carries out the inspection and testing of machines built by private firms. Every machine is submitted to an exacting test before it is passed into the service.
Three broad types of Government machines are manufactured at this establishment. There is that designed essentially for scouting operations, in which
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speed is the all-important factor and which is of the tractor type. Another is the " Reconnoitring " machine known officially as the *' R.E." to-day, but formerly as the " B.E." (Bldriot-Experimental) , a considerable number of which are in commission. This machine is also of the tractor type, carrying a pilot and an observer, and has a maximum speed of 40-50 miles per hour. If required it can further be fitted with an automatic gun for defence and attack. The third craft is essentially a fighting machine. Owing to the introduction of the machine-gun which is fixed in the prow, with the marksman immediately behind it, the screw is placed at the rear. The pilot has his seat behind the gunner. The outstanding feature of these machines is the high factor of safety, which attribute has astonished some of the foremost aviation experts in the world.
Great Britain lagged behind her Continental rivals in the development of the Fourth Arm, especially in matters pertaining to motive power. For some time reliance was placed upon foreign light high- speed explosion motors, but private enterprise was encouraged, with the result that British motors comparing favourably in every respect with the best productions upon the Continent are now available. Development is still proceeding, and there is every evidence that in the near future entire reliance will be placed upon the native motor.
Undoubtedly, as the war progresses, many valu- able lessons will be learned which will exercise an
PROBLEMS OF AERONAUTICS 93
important bearing upon the design and construction of warplanes. The ordeals to which the machines are submitted in miUtary duties are far more severe than any imposed by the conditions of commerce. Accordingly there is every indication that the conflict upon the Continent will represent a distinctive epoch in aeroplane design and construction. Many problems still await solution, such as the capacity to hover over a position, and it is quite possible that these complex and baffling questions will be settled definitely as the result of operations in the field. The aeroplane has reached a certain stage of evolution : further progress is virtually impossible unless something revolutionary is revealed, perfected, and brought to the practical stage.
CHAPTER VIII
SCOUTING FROM THE SKIES
From the moment when human flight was lifted from the rut of experiment to the field of practical application, many theories, interesting and illumina- ting, concerning the utihty of the Fourth Arm as a mihtary unit were advanced. The general con- sensus of expert opinion was that the flying machine would be useful to glean information concerning the movements of an enemy, rather than as a weapon of offence.
The war is substantiating this argument very completely. Although bomb-dropping is practised somewhat extensively, the results achieved are rather moral than material in their effects. Here and there startling successes have been recorded, especially upon the British side, but these triumphs are outnumbered by the failures in this direction, and merely serve to emphasise the views of the theorists.
The argument was also advanced that, in this particular work, the aeroplane would prove more
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FIRST MILITARY ESSAYS 95
valuable than the dirigible, but actual campaigning has proved conclusively that the dirigible and the heavier-than-air machines have their respective fields of utility in the capacity of scouts. In fact, in the very earliest days of the war, the British airships, though small and slow in movement, proved more serviceable for this duty than their dynamic consorts. This result was probably due to the fact that miUtary strategy and tactics were somewhat nonplussed by the appearance of this new factor. At the time it was an entirely unknown quantity. It is true that aircraft had been employed in the Balkan and the Italo-Ottoman campaigns, but upon such a limited scale as to afford no comprehensive idea of their miUtary value and possibilities.
The beUigerents, therefore, were caught somewhat at a disadvantage, and an appreciable period of time elapsed before the significance of the atrial force could be appreciated, while means of counter- acting or nullifying its influences had to be evolved simultaneously, and according to the exigencies of the moment. At all events, the protagonists were somewhat loth to utilise the dirigible upon an elaborate scale or in an aggressive manner. It was employed more after the fashion of a captive balloon, being sent aloft from a point well behind the front lines of the force to which it was attached, and well out of the range of hostile guns. Its manoeuvres were somewhat circumscribed, and were
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carried out at a safe distance from the enemy, dependence being placed upon the advantages of an elevated position for the gathering of information.
But as the campaign progressed, the airships became more daring. Their ability to soar to a great height offered them complete protection against gun-fire, and accordingly sallies over the hostile lines were carried out. But even here a certain hesitancy became manifest. This was perfectly excusable, for the simple reason that the dirigible, above all, is a fair-weather craft, and disasters, which had overtaken these vessels time after time, rendered prudence imperative. Moreover, but little was known of the range and destructiveness of anti- aircraft guns.
In the duty of reconnoitring the dirigible possesses one great advantage over its heavier-than-air rival. It can remain virtually stationary in the air, the propellers revolving at just sufficient speed to off-set the wind and tendencies to drift. In other words, it has the power of hovering over a position, thereby enabling the observers to complete their task care- fully and with deliberation.
On the other hand, the means of enabling an aeroplane to hover still remain to be discovered. It must travel at a certain speed through the air to maintain its dynamic equilibrium, and this speed is often too high to enable the airman to complete his reconnaissance with sufficient accuracy to be of value to the forces below. All that the aeroplane
HOVERING 97
can do is to circle above a certain position until the observer is satisfied with the data he has collected.
But hovering on the part of the dirigible is not without conspicuous drawbacks. The work of observation cannot be conducted with any degree of accuracy at an excessive altitude. Experience has proved that the range of the latest types of anti- aircraft weapons is in excess of anticipations. The result is that the airship is useless when hovering beyond the zone of fire. The atmospheric haze, even in the clearest weather, obstructs the observer's vision. The caprices of this obstacle are extra- ordinary, as anyone who has indulged in ballooning knows fully well. On a clear summer's day I have been able to see the ground beneath with perfect distinctness from a height of 4,500 feet, yet when the craft had ascended a further two or three hundred feet, the panorama was blurred. A film of haze lies between the balloon and the ground beneath. And the character of this haze is continually changing, so that the aerial observer's task is rendered addi- tionally difficult. Its effects are particularly notice- able when one attempts to photograph the view unfolded below. Plate after plate may be exposed and nothing will be revealed. Yet at a shghtly lower altitude the plates may be exposed and perfectly sharp and well-defined images will be obtained.
Seeing that the photographic eye is keener and more searching than the human organ of sight,
H
98 AEROPLANES AND DIRIGIBLES
it is obvious that this haze constitutes a very for- midable obstacle. German military observers, who have accompanied the Zeppelins and Parsevals on numerous aerial journeys under varying conditions of weather, have repeatedly drawn attention to this factor and its caprices, and have not hesitated to venture the opinion that it would interfere seriously with military aerial reconnaissances, and also that it would tend to render such work extremely hazardous at times.
When these conditions prevail the dirigible must carry out its work upon the broad lines of the aeroplane. It must descend to the level where a clear view of the ground may be obtained, and in the interests of safety it has to keep on the move. To attempt to hover within 4,000 feet of the ground is to court certain disaster, inasmuch as the vessel offers a magnificent and steady target which the average gunner, equipped with the latest sighting devices and the most recent types of guns, scarcely could fail to hit.
But the airman in the aeroplane is able to descend to a comparatively low level in safety. The speed and mobility of his machine constitute his protection. He can vary his altitude, perhaps only thirty or forty feet, with ease and rapidity, and this erratic movement is more than sufficient to perplex the marksmen below, although the airman is endangered if a rafale is fired in such a manner as to cover a wide zone.
RECONNOITRING 99
Although the aeroplane may travel rapidly it is not too fleet for a keen observer who is skilled in his peculiar task. He may only gather a rough idea of the disposition of troops, their movements, the lines of communication, and other details which are indispensable to his commander, but in the main the intelligence will be fairly accurate. Undulating flight enables him to determine speedily the altitude at which he is able to obtain the clearest views of the country beneath. Moreover, owing to his speed he is able to complete his task in far less time than his colleague operating in the dirigible, the result being that the information placed at the disposal of his superior officers is more to the moment, and accordingly of greater value.
Reconnoitring by aeroplane may be divided into two broad categories, which, though correlated to a certain degree, are distinctive, because each consti- tutes a specific phase in military operations. They are known respectively as " tactical " and '' strategical " movements. The first is somewhat limited in its scope as compared with the latter, and has invariably to be carried out rapidly, whereas the strategical reconnaissance may occupy several hours.
The tactical reconnaissance concerns the corps or divisional commander to which the warplane is attached, and consequently its task is confined to the observation of the line immediately facing the particular corps or division. The aviator does not necessarily penetrate beyond the lines of
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100 AEROPLANES AND DIRIGIBLES
the enemy, but, as a rule limits his flight to some distance from his outermost defences. The airman must possess a quick eye, because his especial duty is to note the disposition of the troops immediately facing him, the placing of the artillery, and any local movements of the forces that may be in progress. Consequently the aviator engaged on this service may be absent from his lines for only a few minutes, comparatively speaking ; the intelligence he acquires must be speedily communicated to the force to which he is attached, because it may influence a local movement.
The strategical reconnaissance, on the other hand, affects the whole plan of campaign. The aviators told off for this duty are attached to the staff of the Commander-in-Chief, and the work has to be carried out upon a far more comprehensive and elaborate scale, while the airmen are called upon to penetrate well into the hostile territory to a point thirty, forty, or more miles beyond the outposts.
The procedure is to instruct the flier either to carry out his observations of the territory generally, or to report at length upon a specified stretch of country. In the latter event he may fly to and fro over the area in question until he has acquired all the data it is possible to collect. His work not only comprises the general disposition of troops, defences, placing of artillery, points where reserves are being held, high-roads, railways, base camps.
TRIALS OF THE AIRMAN loi
and so forth, but he is also instructed to bring back as correct an idea as possible of what the enemy proposes to do, so that his Commander-in-Chief may adjust his moves accordingly. In order to perform this task with the requisite degree of thoroughness it is often necessary for the airman to remain in the air for several hours continuously, not returning, in fact, until he has completed the allotted duty.
The airman engaged in strategical aerial recon- naissance must possess, above all things, what is known as a " military " eye concerning the country he traverses. He must form tolerably correct estimates of the forces beneath and their character. He must possess the ability to read a map rapidly as he moves through the air and to note upon it all information which is likely to be of service to the General Staff. The ability to prepare military sketches rapidly and intelligibly is a valuable attribute, and skill in aerial photography is a decidedly useful acquisition.
Such men must be of considerable stamina, inasmuch as great demands are made upon their powers of endurance. Being aloft for several hours imposes a severe tax upon the nervous system, while it must also be borne in mind that all sorts and conditions of weather are likely to be encountered, more particularly during the winter. Hail, rain, and blizzards may be experienced in turn, while the extreme cold which often prevails in the higher
102 AEROPLANES AND DIRIGIBLES
altitudes during the winter season is a fearful enemy to combat. Often an airman upon his return from such a reconnaissance has been discovered to be so numbed and dazed as a result of the prolonged exposure, that considerable time has elapsed before he has been sufficiently restored to set forth the results of his observations in a coherent, intelligible manner for the benefit of the General Staff. Under these circumstances it is not surprising that the most skilful and experienced aviators are generally reserved for this particular work. In addition to the natural accidents to which the strategical aerial observer is exposed, the dangers arising from hostile gun-fire must not be overlooked. He is manoeuvring the whole time over the enemy's firing zone, where anti-aircraft weapons are disposed strategically, and where every effort is made by artillery to bring him down, or compel him to repair to such a height as to render observation with any degree of accuracy well-nigh impossible.
The methods practised by the German aerial scout vary widely, and are governed in no small measure by the intrepidity and skill of the airman himself. One practice is to proceed alone upon long flights over the enemy's lines, penetrating just as far into hostile territory as the pilot considers advisable, and keeping, of course, within the limits of the radius of action of the machine, as represented by the fuel supply, the while carefully taking mental stock of all that he observes below. It is a kind of roving
AERIAL SKIRMISHING 103
commission without any definite aim in view beyond the collection of general intelligence.
This work, while productive and valuable to a certain degree, is attended with grave danger, as the German airmen have repeatedly found to their cost. Success is influenced very materially by the accuracy of the airman's judgment. A slight miscalculation of the velocity and direction of the wind, or failure to detect any variations in the climatic conditions, is sufficient to prove his undoing. German airmen who essayed journeys of discovery in this manner, often failed to regain their lines because they ventured too far, misjudged the speed of the wind which was following them on the outward run, and ultimately were forced to earth owing to the ex- haustion of the fuel supply during the homeward trip ; the increased task imposed upon the motor, which had to battle hard to make headway, caused the fuel consumption per mile to exceed calcula- tions.
Then the venturesome airman cannot neglect another factor which is adverse to his success. Hostile airmen lie in wait, and a fleet of aeroplanes is kept ready for instant service. They permit the invader to penetrate well into their territory and then ascend behind him to cut off his retreat. True, the invader has the advantage of being on the wing, while the ether is wide and deep, with- out any defined channels of communication. But nine times out of ten the adventurous scout is
104 AEROPLANES AND DIRIGIBLES
trapped. His chances of escape are slender, because his antagonists dispose themselves strategically in the air. The invader outpaces one, but in so doing comes within range of another. He is so harassed that he either has to give fight, or, finding his retreat hopelessly cut off, he makes a det.^rmined dash, trusting to his high speed to carry him to safety. In these driving tactics the French and British airmen have proved thomselves adepts, more par- ticularly the latter, as the chase appeals to their sporting instincts. There is nothing so exhilarating as a quarry who displays a determination to run the gauntlet.
The roving Teuton scout was considerably in evidence in the early days of the war, but two or three weeks' experience emphasised the sad fact that, in aerial strategy, he was hopelessly outmatched by his opponents. His advantage of speed was nullified by the superior tactical and strategical acumen of his antagonists, the result being that the German airman, who has merely been trained along certain lines, who is in many cases nothing more than a cog-wheel in a machine, and who is proverbially slow-witted, has concluded that he is no match for the airmen of the Allies. He found from bitter experience that nothing afforded the Anglo-French military aviators such keen delight as to lie in wait for a " rover," and then to swoop into the air to round him up.
The proportion of these individual scouts who
BRITISH ASCENDANCY 105
were either brought down, or only just succeeded in reaching safety within their own hues, and who were able to exhibit serious wounds as evidence of the severity of the aerial tussle, or the narrowness of the escape, has unnerved the Teuton airmen as a body to a very considerable extent. Often, even when an aeroplane descended within the German lines, it was found that the roving airman had paid the penalty for his rashness with his life, so that his journey had proved in vain, because all the intelli- gence he had gained had died with him, or, if committed to paper, was so unintelligible as to prove useless.
It was the success of the British airmen in this particular field of duty which was responsible for the momentous declaration in Field-Marshal Sir John French's famous despatch : — " The British Flying Corps has succeeded in establishing an individual ascendancy, which is as serviceable to us as it is damaging to the .enemy .... The enemy have been less enterprising in their flights. Some- thing in the direction of the mastery of the air has already been gained."
The methods of the British airmen are in vivid contrast to the practice of the venturesome Teuton aerial rovers described above. While individual flights are undertaken they are not of unknown duration or mileage. The man is given a definite duty to perform and he ascends merely to fulfil it, returning with the information at the earhest
io6 AEROPLANES AND DIRIGIBLES
possible moment. It is atrial scouting with a method. The intelUgence is required and obtained for a specific purpose, to govern a contemplated move in the grim game of war.
Even then the flight is often undertaken by two or more airmen for the purpose of checking and counterchecking information gained, or to ensure such data being brought back to headquarters, since it is quite possible that one of the party may fall a victim to hostile fire. By operating upon these lines there is very little likelihood of the mission proving a complete failure. Even when raids upon certain places such as Diisseldorf, Friedrichshafen or Cuxhaven are planned, complete dependence is not placed on one individual. The machine is accompanied, so that the possibility of the appointed task being consummated is trans- formed almost into a certainty.
The French flying men work upon broadly similar lines. Their fleet is divided into small squadrons each numbering four, six, or more machines, according to the nature of the contem- plated task. Each airman is given an area of territory which is to be reconnoitred thoroughly. In this way perhaps one hundred or more miles of the enemy's front are searched for information at one and the same time. The units of the squadron start out, each taking the appointed direction according to the preconceived plan, and each steering by the aid of compass and map. They are
THE OBSERVER'S DUTIES 107
urged to complete the work with all speed and to return to a secret rendezvous.
Later the air is alive with the whirring of motors. The machines are coming back and all converging to one point. They vol-plane to the earth and grace- fully settle down within a short distance of each other at the rendezvous. The pilots collect and each relates the intelligence he has gained. The data are collated and in this manner the General Staff is able to learn exactly what is transpiring over a long stretch of the hostile lines, and a considerable distance to the rear of his advance works. Possibly five hundred square miles have been reconnoitred in this manner. Troops have been massed here, lines of communication extend somewhere else, while convoys are moving at a third place. But all has been observed, and the commanding officer is in a position to re-arrange his forces accordingly. It is a remarkable example of method in military tactics and strategy, and conveys a striking idea of the degree to which aerial operations have been organised.
After due deliberation it is decided that the convoys shall be raided, or that massed troops shall be thrown into confusion, if not dispersed. The squadron is ordered to prepare for another aerial journey. The roads along which the convoys are moving are indicated upon the map, or the position of the massed troops in bivouac is similarly shown. The airmen load their machines with a full charge of
io8 AEROPLANES AND DIRIGIBLES
bombs. When all is ready the leader ascends, followed in rapid succession by the other units, and they whirr through the air in single file. It now becomes a grim game of foUow-my-leader.
The leader detects the convoy, swoops down, suddenly launches his missiles, and re-ascends. He does not deviate a foot from his path to observe the effects of his discharge, as the succeeding aero- plane is close behind him. If the leader has missed then the next airman may correct his error. One after another the machines repeat the manoeuvre, in precisely the same manner as the units of a battleship squadron emulate the leading vessel when attacking the foe. The tactical evolutions have been laid down, and there is rigid adherence thereto, because only thereby may success be achieved. When the last war-plane has completed its work, the leader swings round and repeats the dash upon the foe. A hail of bullets may scream around the men in the air, but one and all follow faithfully in the leader's trail. One or more machines may fail in the attack, and may even meet with disaster, but nothing interferes with the movements of the squadron as a whole. It is the homogeneity of the attacking fleet which tells, and which undermines the moral of the enemy, even if it does not wreak decisive material devastation. The work accomplished to the best of their ability, the airmen speed back to their lines in the same forma- tion.
AERIAL SKETCHING 109
At first sight reconnoitring from aloft may appear a simple operation, but a little reflection will reveal the difficulties and arduousness of the work. The observer, whether he be specially deputed, or whether the work be placed in the hand of the pilot himself — in this event the operation is rendered additionally trying, as he also has to attend to his machine — • must keep his eyes glued to the ground beneath and at the same time be able to read the configuration of the panorama revealed to him. He must also keep in touch with his map and compass, so as to be positive of his position and direction. He must be a first-class judge of distances and heights.
When flying rapidly at a height of 4,000 feet or more, the country below appears as a perfect plane, or flat stretch, although as a matter of fact it may be extremely undulating. Consequently, it is by no means a simple matter to distinguish eminences and depressions, or to determine the respective and relative heights of hills.
If a rough sketch is required, the observer must be rapid in thought, quick in determination, and facile with his pencil, as the machine, no matter how it may be slowed down, is moving at a relatively high speed. He must consult his map and compass frequently, since an airman who loses his bearings is useless to his commander-in-chief. He must have an eagle eye, so as to be able to search the country unfolded below, in order to gather all the information which is likely to be of value to his
no AEROPLANES AND DIRIGIBLES
superior officers. He must be able to judge accur- ately the numbers of troops arrayed beneath him, the lines of the defensive works, to distinguish the defended from the dummy lines which are thrown up to baffle him, and to detect instantly the movement of the troops and the direction, as well as the roads, along which they are proceeding. Reserves and their complement, artillery, railway-lines, roads, and bridges, if any, over streams and railways must be noted : in short he must obtain an eye photograph of the country he observes and grasp exactly what is happening there. In winter, with the thermometer well down, a blood-freezing wind blowing, wreaths of clouds drifting below and obscuring vision for minutes at a time, the rain possibly pelting down as if presaging a second deluge, the plight of the vigilant human eye aloft is far from enviable.
Upon the return of the machine to its base, the report must be prepared without delay. The picture recorded by the eye has to be set down clearly and intelhgibly with the utmost speed. The requisite indications must be made accurately upon the map.. Nothing of importance must be omitted : the most trivial detail is often of vital importance.
A facile pencil is of inestimable value in such operations. While aloft the observer does not trust to his memory or his eye picture, but commits the essential factors to paper in the form of a code, or what may perhaps be described more accurately
MESSAGES FROM THE AIR iii
as a shorthand pictorial interpretation of the things he has witnessed. To the man in the street such a record would be unintelligible, but it is pregnant with meaning, and when worked out for the guidance of the superior officers is a mass of invaluable detail.
At times it so happens that the airman has not been able to complete his duty within the time anticipated by those below. But he has gathered certain information which he wishes to communicate without coming to earth. Such data may be dropped from the clouds in the form of maps or messages. Although wireless telegraphy is available for this purpose, it suffers from certain drawbacks. If the enemy possesses an equipment which is within range of that of the air-craft and the force to which it belongs, communications may be nulhfied by the enemy throwing out a continuous stream of useless signals which " jamb " the intelligence of their opponents.
If a message — ^written in code — or a map is to be dropped from aloft it is enclosed within a special metallic cylinder, fitted with a vane tail to ensure direction of flight when launched, and with a de- tonating head. This is dropped overboard. When it strikes the ground the detonator fires a charge which emits a report without damaging the message- container, and at the same time fires a combustible charge emitting considerable smoke. The noise attracts anyone in the vicinity of the spot where
112 AEROPLANES AND DIRIGIBLES
the message has fallen, while at the same time the clouds of smoke guide one to the point and enable the cylinder to be recovered. This device is ex- tensively used by the German aviators, and has proved highly serviceable ; a similar contrivance is adopted by French airmen.
There is one phase of aerial activity which remains to be demonstrated. This is the utilisation of aerial craft by the defenders of a besieged position such as a ring of fortifications or fortified city. The utility of the Fourth Arm in this province has been the subject of considerable speculation. Expert opinion maintains that the advantage in this particular connection would rest with the besiegers. The latter would be able to ascertain the character of the defences and the defending gun-force, by means of the aerial scout, who would prove of inestimable value in directing the fire of the besieging forces.
On the other hand it is maintained that an aerial fleet would be useless to the beleaguered. In the first place the latter would experience grave diffi- culties in ascertaining the positions of the attacking and fortress-reducing artillery, inasmuch as this could be masked effectively, and it is thought that the aerial force of the besieged would be speedily reduced to impotence, since it would be sub- jected to an effective concentrated fire from the ring of besieging anti-aircraft guns and other weapons. In other words, the theory prevails that an aerial fleet, no matter how efficient, would be
AIR-CRAFT IN SIEGES 113
rendered ineffective for the simple reason that it would be the initial object of the besieger's attack. Possibly the stern test of experience will reveal the fallacy of these contentions as emphatically as it has disproved others. But there is one point upon which authorities are unanimous. If the artillery of the investing forces is exposed and readily distinguishable, the aerial forces of the beleaguered will bring about its speedy annihilation, as the defensive artillery will be concentrated upon that of the besiegers.
CHAPTER IX
THE AIRMAN AND ARTILLERY
There is one field in which the airman has achieved distinctive triumphs. This is in the guidance of artillery fire. The modern battle depends first and foremost upon the fierce effec- tiveness of big-gun assault, but to ensure this reliable direction is imperative. No force has proved so invaluable for this purpose as the man- of-the-air, and consequently this is the province in which he has been exceptionally and successfully active.
It will be recalled that in the Japanese investiture of Port Arthur during the Russo-Japanese war, thousands of lives were expended upon the retention and assault of 203 Metre Hill. It was the most blood-stained spot upon the whole of the Eastern Asiatic battlefield. General Nogi threw thousands after thousands of his warriors against this rampart while the Russians defended it no less resolutely. It was captured and re-captured ; in fact, the fighting round this eminence was so intense that it
"4
203 METRE HILL 115
appeared to the outsider to be more important to both sides than even Port Arthur itself.
Yet if General Nogi had been in the possession of a single aeroplane or dirigible it is safe to assert that scarcely one hundred Japanese or Russian soldiers would have met their fate upon this hill. Its value to the Japanese lay in one sole factor. The Japanese heavy guns shelling the harbour and the fleet it contained were posted upon the further side of this eminence and the fire of these weapons was more or less haphazard. No means of directing the artillery upon the vital points were available ; 203 Metre Hill interrupted the line of sight. The Japanese thereupon resolved to capture the hill, while the Russians, equally appreciative of the obstruction it offered to their enemy, as valiantly strove to hold it. Once the hill was captured and the fire of the Japanese guns could be directed, the fate of the fortress was sealed.
Similar conditions have prevailed during the present campaign, especially in the western theatre of war, where the ruggedness of the country has tended to render artillery fire ineffective and expen- sive unless efficiently controlled. When the German Army attacked the line of the British forces so vehemently and compelled the retreat at Mons, the devastating fire of the enemy's artillery was directed almost exclusively by their airmen, who hovered over the British lines, indicating exactly the point where gun-fire could work the maximum
I 2
ii6 AEROPLANES AND DIRIGIBLES
of havoc. The instant concentration of massed artillery fire upon the indicated positions speedily rendered one position after another untenable.
The Germans maintained the upper hand until at last the aerial forces of the British Expeditionary Army came into action. These airmen attacked the Teuton atrial craft without the slightest hesi- tation, and in a short while rendered cloudland absolutely unhealthy. The sequel was interesting. As if suddenly blinded, the German artillery fire immediately deteriorated. On the other hand, the British artillery, now having the benefit of aSrial guidance, was able to repay the German onslaughts with interest, and speedily compelled that elaborate digging-in of the infantry lines which has now become so characteristic of the opposing forces.
So far as the British lines are concerned the men in the trenches keep a sharp look-out for hostile aeroplanes. The moment one is observed to be advancing, all the men seclude themselves and maintain their concealment. To do otherwise is to court a raking artillery outburst. The German aeroplane, detecting the tendency of the trenches, describes in the air the location of the vulnerable spot and the precise disposition by flying immediately above the line. Twice the manoeuvre is repeated, the second movement evidently being in the character of a check upon the first observation, and in accordance with instructions, whereupon the Tommies, to quote their own words, " know
LOCATING TROOPS 117
they are in for it ! " Ere the aeroplane has com- pleted the second manoeuvre the German guns ring out.
The facility with which artillery fire can be con- centrated through the medium of the aeroplane is amazing. In one instance, according to the story related to me by an officer, " a number of our men were resting in an open field immediately behind the second line of trenches, being in fact the reserves intended for the relief of the front lines during the following night. An aeroplane hove in sight. The men dropped their kits and got under cover in an adjacent wood. The aeroplane was flying at a great height and evidently laboured under the impression that the kits were men. Twice it flew over the field in the usual manner, and then the storm of shrapnel, ' Jack Johnsons ' and other tokens from the Kaiser rained upon the confined space. A round four hundred shells were dropped into that field in the short period of ten minutes, and the range was so accurate that no single shell feU outside the space. Had the men not hurried to cover not one would have been left alive to tell the tale, because every square foot of the land was searched through and through. We laughed at the short-sightedness of the airman who had contributed to such a waste of valuable shot and shell, but at the same time appreciated the narrowness of our own escape."
The above instance is by no means isolated. It
ii8 AEROPLANES AND DIRIGIBLES
has happened time after time. The sHghtest sign of activity in a trench when a " Taube " is over- head suffices to cause the trench to be blown to fragments, and time after time the British soldiers have had to lie prone in their trenches and suffer partial burial as an alternative to being riddled by shrapnel.
The method of ascertaining the range of the target from the indications given by the aeroplane are of the simplest character. The German method is for the aerial craft to fly over the position, and when in vertical line therewith to discharge a handful of tinsel, which, in falling, glitters in the sunlight, or to launch a smoking missile which answers the same purpose as a projectile provided with a tracer. This smoke-ball being dropped over the position leaves a trail of black or whitish smoke according to the climatic conditions which prevail, the object being to enable the signal to be picked up with the greatest facility. The height at which the aerial •craft is flying being known, a little triangulation upon the part of the observer at the firing point enables him to calculate the range and to have the guns laid accordingly.
When the aerial craft has been entrusted with the especial duty of directing artillery-fire, a system of communication between the aerial observer and the officer in charge of the artillery is established, conducted, of course, by code. In the British Army, signalling is both visual and audible. In
SMOKE SIGNALS 119
daylight visual signalling is carried out by means of coloured flags or streamers and smoke-signals, while audible communication is effected by means of a powerful horn working upon the siren principle and similar to those used by automobiles. Both flags and sound-signals, however, are restricted owing to the comparatively short distances over which they can be read with any degree of accuracy. The smoke-signal therefore appears to be the most satisfactory and reliable, as the German airmen have proved conclusively, for the simple reason that the trail of smoke may be picked up with comparative ease, even at a distance, by means of field glasses. The tinsel too, is readily distin- guishable, particularly in bright weather, for the glittering surface, catching the sun-light, acts some- what in the manner of a heliograph.
The progress of the airman is followed by two officers at the base from which he started. One is equipped with the director, while the second takes the range. Directly this has been found as a result of calculation, the guns are laid ready for firing. In those cases where the enemy's artillery is concealed perhaps behind a hill, the airman is of incalculable value, inasmuch as he is able to reveal a position which otherwise would have to be found by con- siderable haphazard firing, and which, even if followed by a captive balloon anchored above the firing point, might resist correction.
The accuracy of the airman's work in communi-
120 AEROPLANES AND DIRIGIBLES
eating the range has been responsible for the high efficiency of the British and French artillery. The latter, with the 75 millimetre quick-firing gun, is particularly adapted to following up the results of the aeroplane's, reconnaissance, especially with the system of rafale fire, because the whole position can be searched through and through within a minute or two. According to information which has been given to me by our artillery officers, the British system also has proved disastrous to the enemy. The practice is to get the range as communicated by the aeroplane, to bring the artillery into position speedily, to discharge salvo after salvo with all speed for a few minutes, and then to wheel the artillery away before any hostile fire can be returned. The celerity with which the British artillery comes into, and goes out of, action has astonished even our own authorities. This mobility is of unique valile : it is taking advantage of a somewhat slow-witted enemy with interest. By the time the Germans have opened fire upon the point whence the British guns were discharged, the latter have disappeared and are ready to let fly from another point, some distance away, so that the hostile fire is abortive. Mobility of such a character is decidedly unnerving and baffiing even to a quick-witted opponent.
In his search for hostile artillery the airman runs grave risks and displays remarkable resource. It is invariably decided, before he sets out, that he shall always return to a certain altitude to communicate
SIGNALLING 121
signals. Time after time the guns of the enemy have been concealed so cunningly from aerial observation as to pass unnoticed. This trait became more pronounced as the campaigns of the Aisne progressed. Accordingly the airman adopts a daring procedure. He swoops down over suspicious places, where he thinks guns may be lurking, hoping that the enemy will betray its presence. The ruse is invariably successful. The airman makes a sudden dive towards the earth. The soldiers in hiding below, who have become somewhat demoralised by the accuracy of the British aerial bomb-throwers, have an attack of nerves. They open a spirited fusillade in the hope of bringing the airman to earth. But their very excitement contributes to his safety. The shots are fired without careful aim and expend themselves harm- lessly. Sweeping once more upwards, the airman regains the pre-determined level, performs a certain evolution in the air which warns the observer at his base that he has made a discovery, and promptly drops his guiding signal directly over the point from which he has drawn fire.
Operations at night are conducted by means of coloured lights or an electrical searchlight system. In the former instance three lights are generally carried — white, red, and green — each of which has a distinctive meaning. If reliance is placed upon the electric Hght signalhng lamp, then communications are in code. But night operations are somewhat
122 AEROPLANES AND DIRIGIBLES
difficult and extremely dangerous, except when the elements are propitious. There is the ground mist which blots everything from sight, rendering reconnaissance purely speculative. But on a clear night the airman is more likely to prove successful. He keeps a vigilant eye upon all ground-lights and by close observation is able to determine their significance. It is for this reason that no hghts of any description are permitted in the advance trenches. The striking of a match may easily betray a position to the alert eye above.
So far as the British Army is concerned a complete code is in operation for communicating between aeroplanes and the ground at night. Vary's lights are used for this purpose, it being possible to dis- tinguish the respective colours at a distance of six miles and from an altitude of 2,000 feet. The lights are used both by the aeroplane and the battery of artillery.
The code is varied frequently, but the following conveys a rough idea of how communication is carried out by this means under cover of darkness. The aeroplane has located its objective and has returned to the pre-arranged altitude. A red light is thrown by the airman. It indicates that he is directly over the enemy's position. A similarly coloured light is shown by the artillery officer, which intimates to the airman that his signal has been observed and that the range has been taken.
In observing the effects of artillery fire a code
AERIAL CODES 123
of signals is employed between the airman and the artillery officer to indicate whether the shot is " long " or " short/' to the right or to the left of the mark, while others intimate whether the fuse is correctly timed or otherwise. It is necessary to change the code fairly frequently, not only lest it should fall into the enemy's hands, but also to baffle the hostile forces ; otherwise, after a Httle experience, the latter would be able to divine the significance of the signals, and, in anticipation of being greeted with a warm fusillade, would complete hurried arrangements to mitigate its effects, if not to vacate the position until the bombardment had ceased.
Sufficient experience has already been gathered, however, to prove the salient fact that the airman is destined to play an important part in the direction and control of artillery-fire. Already he has been responsible for a re-arrangement of strategy and tactics. The man aloft holds such a superior position as to defy subjugation ; the alternative is to render his work more difficult, if not absolutely impossible.
CHAPTER X
BOMB-THROWING FROM AIR-CRAFT
During the piping times of peace the utiUty of aircraft as weapons of offence was discussed freely in an academic manner. It was urged that the usefulness of such vessels in this particular field would be restricted to bomb-throwing. So far these contentions have been substantiated during the present campaign. At the same time it was averred that even as a bomb-thrower the ship of the air would prove an uncertain quantity, and that the results achieved would be quite contrary to expectations. Here again theory has been sup- ported by practice, inasmuch as the damage wrought by bombs has been comparatively insignificant.
The Zeppelin raids upon Antwerp and Britain were a fiasco in the military sense. The damage inflicted by the bombs was not at all in proportion to the quantity of explosive used. True, in the case of Antwerp, it demoralised the civilian population somewhat effectively, which perhaps was the desired end, but the military results were niL
BOMB-THROWING 1 25
The Zeppelin, and indeed all dirigibles of large size, have one advantage over aeroplanes. They are able to throw bombs of larger size and charged with greater quantities of high explosive and shrapnel than those which can be hurled from heavier-than- air machines. Thus it has been stated that the largest Zeppelins can drop single charges exceeding one ton in weight, but such a statement is not to be credited.
The shell generally used by the Zeppelin measures about 47 inches in length by 8J inches in diameter, and varies in weight from 200 to 242 pounds. Where destruction pure and simple is desired, the shell is charged with a high explosive such as picric acid or T.N.T., the colloquial abbreviation for the devastating agent scientifically known as ** Trini- trotoluene," the base of which, in common with all the high explosives used by the different Powers and variously known as lyddite, melinite, cheddite, and so forth, is picric acid. Such a bomb, if it strikes the objective, a building, for instance, fairly and squarely, may inflict widespread material damage.
On the other hand, where it is desired to scatter death, as well as destruction, far and wide, an elaborate form of shrapnel shell is utilised. The shell in addition to a bursting charge, contains bullets, pieces of iron, and other metallic fragments. When the shell bursts, their contents, together with the pieces of the shell which is likewise broken up
126 AEROPLANES AND DIRIGIBLES
by the explosion, are hurled in all directions over a radius of some 50 yards or more, according to the bursting charge.
These shells are fired upon impact, a detonator exploding the main charge. The detonator, com- prising fulminate of merciury, is placed in the head or tail of the missile. To secure perfect detonation and to distribute the death-dealing contents evenly in all directions, it is essential that the bomb should strike the groimd almost at right angles : otherwise the contents are hurled irregularly and perhaps in one direction only. One great objection to the per- cussion system, as the method of impact detonation is called, is that the damage may be localised. A bomb launched from a height of say 1,000 feet attains terrific velocity, due to the force of gravity in conjunction with its own weight, in consonance with the law concerning a falling body, by the time it reaches the ground. It buries itself to a certain depth before bursting so that the forces of the explosion become somewhat muffled as it were. A huge deep hole — a miniature volcano crater — is formed, while all the glass in the immediate vicinity of the explosion may be shattered by the concussion, and the walls of adjacent buildings be bespattered with shrapnel.
Although it is stated that an airship is able to drop a single missile weighing one ton in weight, there has been no attempt to prove the contention by practice. In all probability the heaviest shell
*'-'* ^:t »», '
The "Flechette" or Steei. Dart. Actual size.
A Zeppelin Bomb.
"^ .,
BOMB-THROWING 127
launched from a Zeppelin has not exceeded 300 pounds. There is one cogent reason for such a belief. A bomb weighing one ton is equivalent to a similar weight of ballast. If this were dis- carded suddenly the equilibrium of the dirigible would be seriously disturbed — it would exert a tendency to fly upwards at a rapid speed. It is doubtful whether the planes controlling movement in the vertical plane would ever be able to counter- act this enormous vertical thrust. Something would have to submit to the strain. Even if the dirigible displaced say 20 tons, and a bomb weighing one ton were discharged, the weight of the balloon would be decreased suddenly by approximately five per cent., so that it would shoot upwards at an alarming speed, and some seconds would elapse before control was regained.
The method of launching bombs from airships varies considerably. Some are released from a cradle, being tilted into position ready for firing, while others are discharged from a tube somewhat reminiscent of that used for firing torpedoes, with the exception that little or no initial impetus is imparted to the missile ; the velocity it attains is essentially gravitational.
The French favour the tube-launching method since thereby it is stated to be possible to take more accurate aim. The objective is sighted and the bomb launched at the critical moment. In some instances the French employ an automatic detonator
128 AEROPLANES AND DIRIGIBLES
which corresponds in a certain measure to the time-fuse of a shrapnel shell fired from a gun.
The bomb-thrower reads the altitude of his airship as indicated by his barometer or other recording instrument, and by means of a table at his command ascertains in a moment the time which will elapse before the bomb strikes the ground. The automatic detonator is set in motion and the bomb released to explode approximately at the height to which it is set. When it bursts the full force of the explosion is distributed downwards and laterally. Owing to the difficulty of ensuring the explosion of the bomb at the exact height desired, it is also made to explode upon impact so as to make doubly sure of its efhcacy.
Firing timed bombs from aloft, however, is not free from excitement and danger, as the experience of a French airman demonstrates. His dirigible had been commanded to make a night-raid upon a railway station which was a strategical junction for the movement of the enemy's troops. Although the hostile searchlights were active, the airship contrived to slip between the spokes of light without being observed. By descending to a comparatively low altitude the pilot was able to pick up the ob- jective.
Three projectiles were discharged in rapid succes- sion and then the searchlights, being concentrated, struck the airship, revealing its presence to the troops below. Instantly a spirited fusillade broke out.
PERILS OF BOMB-THROWER 129
The airmen, by throwing ballast and other portable articles overboard pell-mell, rose rapidly, pursued by the hostile shells.
In the upward travel the bomb-thrower decided to have a parting shot. The airship was steadied momentarily to enable the range to be taken, the automatic detonator was set going and the bomb slipped into the launching tube. But for some reason or other the missile jambed.
The situation was desperate. In a few seconds the bomb would burst and shatter the airship. The bomb-thrower grabbed a tool and climbing into the rigging below hacked away at the bomb- throwing tube until the whole equipment was cut adrift and fell clear of the vessel. Almost instantly there was a terrific explosion in mid-air. The blast of air caused the vessel to roll and pitch in a dis- concerting manner, but as the airman permitted the craft to continue its upward course unchecked, she soon steadied herself and was brought under control once more.
The bomb carried by aeroplanes differs consider- ably from that used by dirigibles, is smaller and more convenient to handle, though considering its weight and size it is remarkably destructive. In this instance complete reliance is placed upon detonation by impact. The latest types of British war-plane bombs have been made particularly formidable, those employed in the " raids in force " ranging up to 95 pounds in weight.
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130 AEROPLANES AND DIRIGIBLES
The type of bomb which has proved to be the most successful is pear-shaped. The tail spindle is given an arrow-head shape, the vanes being utiHsed to steady the downward flight of the missile. In falling the bomb spins round, the rotating speed increasing as the projectile gathers velocity. The vanes act as a guide, keeping the projectile in as vertical a plane as possible, and ensuring that the rounded head shall strike the ground. The earlier types of bombs were not fitted with these vanes, the result being that sometimes they turned over and over as they fell through- the air, while more often than not they failed to explode upon striking the ground.
The method of launching the bomb also varies considerably, experience not having indicated the most efficient method of consummating this end. In some cases the bombs are carried in a cradle placed beneath the aeroplane and launched merely by tilting them in a kind of shng, one by one, to enable them to drop to the ground, this action being controlled by means of a lever. In another instance they are dropped over the side of the car by the pilot, the tail of the bomb being fitted with a swivel and ring to facilitate the operation. Some of the French aviators favour a still simpler method. The bomb is attached to a thread and lowered over the side. At the critical moment it is released simply by severing the thread. Such aeroplane bombs, however, constitute a menace to the machine
THE MARTEN-HALE BOMB 131
and to the pilot. Should the bomb be struck by hostile rifle or shell fire while the machine is aloft, an explosion is probable ; while should the aero- plane make an abrupt descent the missiles are likely to be detonated.
A bomb which circumvents this menace and which in fact will explode only when it strikes the ground is that devised by Mr. Marten-Hale. This pro- jectile follows the usual pear-shape, and has a rotating tail to preserve direction when in flight. The detonator is held away from the main charge by a collar and ball-bearing which are held in place by the projecting end of a screw-releasing spindle. When the bomb is dropped the rotating tail causes the spindle to screw upwards until the pro- jection moves away from the steel balls, thereby allowing them to fall inward when the collar and the detonator are released. In order to bring about this action the bomb must have a fall of at least 200 feet.
When the bomb strikes the ground the detonator falls down on the charge, fires the latter, and thus brings about the bursting of the bomb. The projectile is of the shrapnel type. It weighs 20 pounds complete, is charged with some four pounds of T.N.T., and carries 340 steel balls, which repre- sent a weight of 5f pounds.
The firing mechanism is extremely sensitive and the bomb will burst upon impact with the hull of an airship, water, or soft soil. This projectile,
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132 AEROPLANES AND DIRIGIBLES
when discharged, speedily assumes the vertical position, so that there is every probability that it will strike the ground fairly and squarely, although at the same time such an impact is not imperative, because it will explode even if the angle of incidence be only 5 degrees. It is remarkably steady in its flight, the balancing and the design of the tail frustrating completely any tendency to wobble or to turn turtle while falling. .
Other types of missile may be used. For instance, incendiary bombs have been thrown with success in certain instances. These bombs are similar in shape to the shrapnel projectile, but are charged with petrol or some other equally highly inflammable mixture, and fitted with a detonator. When they strike the objective the bursting charge breaks up the shell, releasing the contents, and simultaneously ignites the combustible.
Another shell is the smoke-bomb, which, up to the present, has been used only upon a restricted scale. This missile is charged with a certain quantity of explosive to burst the shell, and a substance which, when ignited, emits copious clouds of dense smoke. The scope of such a shell is somewhat restricted, it is used only for the purpose of ob- structing hostile artillery fire. The shells are dropped in front of the artillery position and the clouds of smoke which are emitted naturally inter- fere with the operations of the gunners. These bombs have also been used with advantage to denote
BOMB-DROPPING 133
the position of concealed hostile artillery, although their utility in this connection is somewhat un- certain, owing to the difficulty of dropping the bomb so accurately as to enable the range-finders to pick up the range.
Dropping bombs from aloft appears to be a very simple operation, but as a matter of fact it is an extremely difficult matter to strike the target, especially from a high altitude. So far as the aeroplane is concerned it is somewhat at a dis- advantage as compared with the airship, as the latter is able to hover over a position, and, if a spring-gun is employed to impart an initial velocity to the missile, there is a greater probability of the projectile striking the target provided it has been well-aimed. But even then other conditions are likely to arise, such as air-currents, which may swing the missile to one side of the objective. Consequently adequate allowance has to be made for windage, which is a very difficult factor to calculate from aloft.
Bomb-dropping from an aeroplane is even more difficult. If for instance the aeroplane is speeding along at 60 miles an hour, the bomb when released will have a speed in the horizontal plane of 60 miles an hour, because momentarily it is travelling at the speed of the aeroplane. Consequently the shell will describe a curved trajectory, somewhat similar to that shown in Fig. 7.
On the other hand, if the aeroplane is travelling slowly, say at 20 miles an hour, the curve of the
134 AEROPLANES AND DIRIGIBLES
trajectory will be flatter, and if a head wind be prevailing it may even be swept backwards somewhat
V
\
\
\
■\
\^
\
^ \
N
\
\ \
I L
Fig. 7.— Bomb-dropping from a Rapidly-moving Aeroplane.
In order to strike the point D the bomb is released from the
aeroplane A at B. Its curved trajectory is indicated by the
dotted line C.
after it has lost its initial forward momentum, and describe a trajectory similar to that in Fig. 8.
TRAJECTORY OF BOMBS 135
A bomb released from an altitude of 1,000 feet seldom, if ever, makes a bee-line for the earth, even if dropped from a stationary airship. Accordingly,
/
F G. 8. — The Influence of an Adverse Wind upon THE Trajectory of the Bomb.
D is the objective, but the bomb B, released from A, is deflected
by the wind F, which produces the trajectory C, with the
result that the bomb strikes the ground at E.
136 AEROPLANES AND DIRIGIBLES
the airman has to release the bomb before he reaches the target below. The determination of the critical moment for the release is not easy, inasmuch as the airman has to take into his calculations the speed of his machine, his altitude, and the direction and velocity of the air-currents.
The difficulty of aiming has been demonstrated upon several occasions at aviation meetings and other similar gatherings. Monsieur Michelin, who has done so much for aviation in France, offered a prize of £1,000 — $5,000 — in 1912 for bomb-dropping from an aeroplane. The target was a rectangular space marked out upon the ground, measuring 170 feet long by 40 feet broad, and the missiles had to be dropped from a height of 2,400 feet. The prize was won by the well-known American airman, Lieutenant Riley E. Scott, formerly of the United States Army. He dropped his bombs in groups of three. The first round fell clear of the target, but eight of the remaining missiles fell within the area.
In the German competition which was held at Gotha in September of the same year the results were somewhat disappointing. Two targets were provided. The one represented a military bivouac occupying a superficies of 330 square feet, and the other a captive balloon resembling a Zeppelin. The prizes offered were £500, £200, and £80 — $2,500, $1,000 and $400 — respectively, and were awarded to those who made the greatest number of hits.
BOMB-DROPPING 137
The conditions were by no means so onerous as those imposed in the MicheUn contest, inasmuch as the altitude Umit was set at 660 feet, while no machine was to descend within 165 feet. The first competitor completely failed to hit the balloon. The second competitor flying at 800 feet landed seven bombs within the square, but only one other competitor succeeded in placing one bomb within the space.
Bomb-dropping under the above conditions, however, is vastly dissimilar from such work under the grim realities of war. The airman has to act quickly, take his enemy by surprise, avail himself of any protective covering which may exist, and incur great risks. The opposing forces are over- whelmingly against him. The modern rifle, if fired vertically into the air, will hurl the bullet to a height of about 5,000 feet, while the weapons which have been designed to combat aircraft have a range of 10,000 feet or more.
At the latter altitude aggressive tactics are useless. The airman is unable to obtain a clear sharp view of the country beneath owing to the interference offered to vision by atmospheric haze, even in the clearest of weather. In order to obtain reasonable accuracy of aim the corsair of the sky must fly at about 400 feet. In this respect, however, the aeroplane is at a decided advantage, as compared with the dirigible. The machine offers a considerably smaller target and moves with much greater speed. Experience of the war has shown that to attempt
138 AEROPLANES AND DIRIGIBLES
to hurl bombs from an extreme height is merely a waste of ammunition. True, they do a certain amount of damage, but this is due to luck, not judgment.
For success in aSrial bomb operations the human element is mainly responsible. The daring airman is likely to achieve the greatest results, as events have proved, especially when his raid is sudden and takes the enemy by surprise. The raids carried out by Marix, Collet, Briggs, Babington, Sippe and many others have estabHshed this fact incontro- vertibly. In all these operations the airmen suc- ceeded because of their intrepidity and their decision to take advantage of cover, otherwise a prevailing mist or low-lying clouds. FUght-Lieutenant Collet approached the Zeppelin shed at Diisseldorf at an altitude of 6,000 feet. There was a bank of mist below, which he encountered at 1,500 feet. He traversed the depth of this layer and emerged therefrom at a height of only 400 feet above the ground. His objective was barely a qiiarter of a mile ahead. TraveUing at high speed he launched his bombs with what proved to be deadly precision, and disappeared into cover almost before the enemy had grasped his intentions. Lieutenant-Commander, now Flight-Commander, Marix was even more daring. Apparently he had no mist in which to conceal himself but trusted almost entirely to the speed of his machine, which probably at times notched 90 miles per hour. Although his advent was
RAID ON FRIEDRICHSHAFEN 139
detected and he was greeted with a spirited fusillade he clung to his determined idea. He headed straight for the Zeppelin shed, launched two bombs and swung into the higher reaches of the air without a moment's hesitation. His aim was deadly, since both bombs found their mark, and the ZeppeUn docked within was blown up. The intrepid airman experienced several narrow escapes, for his aSroplane was struck twenty times, and one or two of the control wires were cut by passing bullets.
The raid carried out by Commanders Briggs and Babington in company with Lieutenant Sippe upon the Zeppelin workshops at Friedrichshafen was even more daring. Leaving the Allies' lines they ascended to an altitude of 4,500 feet, and at this height held to the pre-arranged course until they encountered a mist, which while protecting them from the alert eyes of the enemy below, was responsible for the separation of the raiders, so that each was forced to act independently and ^to trust to the compass to bring him out of the ordeal successfully. Lieu- tenant Sippe sighted Lake Constance, and taking advantage of the mist lying low upon the water, descended to such an extent that he found himself only a few feet above the roofs of the houses. Swing- ing round to the Lake he descended still lower until at last he was practically skimming the surface of the Lake, since he flew at the amazingly low height of barely seven feet off the water. There is no doubt that the noise of his motor was heard
I40 AEROPLANES AND DIRIGIBLES
plainly by the enemy, but the mist completely enveloped him, and owing to the strange pranks that fog plays with sound deceived his antagonists.
At last, climbing above the bank of vapour, he found that he had overshot the mark, so he turned quickly and sped backwards. At the same time he discovered that he had been preceded by Com- mander Briggs, who was bombarding the shed furiously, and who himself was the object of a concentrated fire. Swooping down once more, Lieutenant Sippe turned, rained his bombs upon the objective beneath, drawing fire upon himself, but co-operating with Commander Babington, who had now reached the scene, he manoeuvred above the works and continued the bombardment until their ammunition was expended, when they sped home- wards under the cover of the mist. Considering the intensity of the hostile fire, it is surprising that the aeroplanes were not smashed to fragments. Undoubtedly the high speed of the machines and the zig-zagging courses which were followed non- plussed the enemy. Commander Briggs was not so fortunate as his colleagues; a bullet pierced his petrol tank, compeUing a hurried descent.
The most amazing feature of these aerial raids has been the remarkably low height at which the airmen have ventured to fly. While such a pro- cedure facilitates marksmanship it increases the hazards. The airmen have to trust implicitly to the fleetness of their craft and to their own nerve.
THE FLECHETTE
141
Bearing in mind the vulnerability of the average aeroplane, and the general absence of protective armouring against rifle fire at almost point-blank range, it shows the important part which the human element is compelled to play in bomb-dropping operations.
Another missile which has been introduced by the French airmen, and which is extremely deadly
Fig. 9.— Section of Uppkr End or Tail of Flechette.
when hurled against dense masses of men, is the steel arrow, or " flechette " as it is called. It is a fiendish projectile consisting in reality of a pencil of sohd pohshed steel, 4f inches in length. The lower end has a sharp tapering point, fths of an inch in length. For a distance of ijth of an inch above this point the cylindrical form of the pencil is pre- served, but for the succeeding three inches to the upper end, the pencil is provided with four equally
142 AEROPLANES AND DIRIGIBLES
spaced angle flanges or vanes (Fig. 9). This flanging of the upper end or tail ensures the arrow spinning rapidly as it falls through the air, and at the same times preserves its vertical position during its descent. The weight of the arrow is two-thirds of an ounce.
The method of launching this fearsome projectile is ingenious. A hundred or even more are packed in a vertical position in a special receptacle, placed upon the floor of the aeroplane, preferably near the foot of the pilot or observer. This receptacle is fitted with a bottom moving in the manner of a trap-door, and is opened by pressing a lever. The aviator has merely to depress this pedal with his foot, when the box is opened and the whole of the contents are released. The fall at first is somewhat erratic, but this is an advantage, as it enables the darts to scatter and to cover a wide area As the rotary motion of the arrows increases during the fall, the direct line of flight becomes more pro- nounced until at last they assume a vertical direction free from all wobbling, so that when they alight upon the target they are quite plumb.
When launched from a height they strike the objective with terrific force, and will readily pene- trate a soldier's helmet and skull. Indeed, when released at a height of 4,000 feet they have been known to pierce a mounted soldier's head, and pass vertically through his body and that of his horse also. Time after time German soldiers have found
OFFENSIVE POWER 143
themselves pinned to the ground through the arrow striking and penetrating their feet. Owing to the extremely light weight of the darts they can be launched in batches of hundreds at a time, and in a promiscuous manner when the objective is a massed body of infantry or cavalry, or a transport convoy. They are extremely effective when thrown among horses even from a comparatively low altitude, not so much from the fatalities they produce, as from the fact that they precipitate a stampede among the animals, which is generally sufficiently serious and frantic to throw cavalry or a transport-train into wild confusion.
Although aerial craft, when skilfully handled, have proved highly successful as weapons of offence, the possibilities of such aggression as yet are scarcely realised ; aerial tactics are in their infancy. Develop- ments are moving rapidly. Great efforts are being centred upon the evolution of more formidable missiles to be launched from the clouds. The airman is destined to inspire far greater awe than at present, to exercise a still more demoralising influence, and to work infinitely more destruction.
CHAPTER XI
ARMOURED AEROPLANES
The stern test of war has served to reveal con- clusively the fact that aerial craft can be put out of action readily and effectively, when once the marksman has picked up the range, whether the gunner be conducting his operations with an anti- aircraft gun stationed upon the ground, or from a hostile machine. It will be remembered that Flight-Commander Briggs, on the occasion of the daring British raid upon the Zeppelin sheds at Friedrichshafen, was brought to the ground by a bullet which penetrated his fuel tank. Several other vessels, British, German, French, and Russian alike, have been thrown out of action in a similar manner, and invariably the craft which has been disabled suddenly in this way has fallen precipi- tately to earth in the fatal headlong dive.
Previous to the outbreak of hostilities there was considerable divergence of opinion upon this subject. The general opinion was that the outspread wings and the stays which constituted the weakest parts of the structure were most susceptible to gun-fire, and
ANTI-AIRCRAFT GUN TRIALS 145
thus were likely to fail. But practice has proved that it is the driving mechanism which is the most vulnerable part of the aeroplane.
This vulnerability of the essential feature of the flying machine is a decisive weakness, and exposes the aviator to a constant menace. It may be quite true that less than one bullet in a thousand may hit the machine, but when the lucky missile does find its billet its effect is complete. The fact must not be overlooked that the gunners who work the batteries of anti-aircraft guns are becoming more and more expert as a result of practice, so that as time progresses and improved guns for such duty are rendered available, the work of the aviator is likely to become more dangerous and difficult. Experience has proved that the high velocity gun of to-day is able to hurl its projectile or shell to an extreme height — far greater than was previously considered possible — so that considerable discretion has to be exercised by the airman, who literally bears his life in his hands.
Although elaborate trials were carried out upon the testing ranges with the weapons devised es- pecially for firing upon flying machines, captive balloons being employed as targets, the data thus obtained were neither conclusive nor illuminating. The actual experiences of airmen have given us some very instructive facts upon this point for the first time.
It was formerly held that the zone of fire that is
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146 AEROPLANES AND DIRIGIBLES
to be considered as a serious danger was within a height of about 4,500 feet. But this estimate was well within the mark. Airmen have foimd that the modern projectiles devised for this phase of opera- tions are able to inflict distinctly serious damage at an altitude of 9,000 feet. The shell itself may have but little of its imparted velocity remaining at this altitude, but it must be remembered that when the missile bursts, the contents thereof are given an independent velocity, and a wide cone of dispersion, which is quite sufficient to achieve the desired end, inasmuch as the mechanism of the modern aeroplane and dirigible is somewhat delicate.
It was for this reason that the possibility of armouring the airship was discussed seriously, and many interesting experiments in this field were carried out. At the same time it was decided that the armouring should be effected upon lines analogous to that prevailing in warship engineering. The craft should not only be provided with defensive but also with aggressive armament. This decision was not viewed with general approbation. It was pointed out that questions of weight would arise, especially in relation to the speed of the machine. Increased weight, unless it were accompanied by a proportionate augmentation of power in the motor, would react against the efficiency and utility of the machine, woiild appreciably reduce its speed, and would affect its climbing powers very adversely. In some quarters it was maintained that as a result
ARMOURED AIR-SHIPS 147
the machine would even prove unsuited to military operations, inasmuch as high speed is the primary factor in these.
Consequently it was decided by the foremost aviating experts that machines would have to be classified and allotted to particular spheres of work, just as warships are built in accordance with the special duty which they are expected to perform. In reconnaissance, speed is imperative, because such work in the air coincides with that of the tor- pedo-boat or scout upon the seas. It is designed to acquire information respecting the movements of the enemy, so as to assist the heavier arms in the plan of campaign. ^ On the other hand, the fighting corsair of the skies might be likened to the cruiser or battleship. It need not possess such a high turn of speed, but must be equipped with hard-hitting powers and be protected against attacking fire.
One attempt to secure the adequate protection against gun-fire from the ground assumed the installation of bullet-proof steel plating, about one- fifth of an inch thick, below the tank and the motor respectively. The disposition of the plating was such as to offer the minimum of resistance to the air and yet to present a plane surface to the ground below. So far as it went this protection was completely effective, but it failed to armour the vital parts against lateral, cross and downward fire while aloft. As the latter is more to be feared
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148 AEROPLANES AND DIRIGIBLES
than the fire from the ground, seeing that it may