INTRODUCTION
When years ago we read in Tennyson’s “Locksley Hall” the following lines:—
Heard the heavens fill with shouting, and there rained a ghastly dew
From the nations’ airy navies grappling in the central blue—
we little dreamt that not very far from the beginning of the twentieth century the fancy of the poet would become the fact of reality; that in the great European war in which the nation is so strenuously engaged, “the wonder that would be” would come to pass.
Though happily, at present, in these isles the din of war is unheard, yet a semi-darkened London and bright searchlights playing on the skies tell the tale of prudent foresight against the advent of the enemy’s airfleet. From the battlefields there daily come the reports of actual battles in the air, sometimes betwixt aëroplane and aëroplane, sometimes between the lighter and heavier than air craft. Often such encounters are death-grip duels. Such conflicts of the air are the direct consequence of the great and important use of both airship and aëroplane as aërial scouts. These are the eyes of encountering armies. To destroy as far as possible this penetrating vision of the enemy and restore to him the fog of war is the untiring aim of either side.
During those first anxious days of the present war the public anxiously awaited news of the doings of the Royal Flying Corps, as well as those of the aviators of our Allies. Expectation was satisfied in the reading of Sir John French’s report to Lord Kitchener, dated September 7th, 1914. Speaking of the use of the aëroplane in the war he says:—
I wish particularly to bring to your Lordship’s notice the admirable work done by the Royal Flying Corps under Sir David Henderson. Their skill, energy, and perseverance have been beyond all praise. They have furnished me with the most complete and accurate information, which has been of inestimable value in the conduct of the operations. Fired at constantly both by friend and foe, and not hesitating to fly in every kind of weather, they have remained undaunted throughout.
Further, by actually fighting in the air, they have succeeded in destroying five of the enemy’s machines.
For those brave heroes of the air our hearts beat with fervid admiration. In accomplishing their all-important tasks they have not only to fear disaster from shot and shell of the enemy, but from the mistaken fire of their comrades and the very forces of nature. These latter, owing to the imperfections of the flying machines, do not entirely spare them; the Royal Flying Corps, in order to become competent to perform the work it is now doing for King and country, has had in manœuvres at home to pay a high price in the sacrifice of human life.
It may, indeed, be reasonably thought that the knowledge of the vast utility of aircraft in the present conflict will dispel the last remnant of prejudice in this country against the development of aërial navigation, and the grudging of a liberal national expenditure on the service of the air. It was, perhaps, this ignoring of practical utility, so vigorously combated by the pioneers in this country, that caused Great Britain to be the last of the Great Powers to seriously take up aircraft for military and naval use. Our delay had been a wonder to many, since theoretically in the past this nation had been to the fore. Nearly half a century ago it led the way of the air by being the first country in the world to found a society for the encouragement of aërial navigation—the Aëronautical Society of Great Britain. It is no exaggeration to say that many of the great principles of human flight were formulated and discussed at the earlier meetings of that society. The late Mr. Wilbur Wright, when he came to this country to receive the gold medal of the society, in his speech testified to the substantial help he had received from the study of the transactions of the oldest aëronautical society in the world. As the pioneer in laying the foundations of aërial science, this country is not without honour amongst the nations.
CHAPTER I
THE EARLIER AËRIAL SCOUTS
Patriotism has been the most powerful factor in developing aërial navigation. Montgolfier experimented with his paper balloons filled with heated air in the desire that his invention might be of use to France in her wars, and throughout the history of both balloons and flying machines we find that it has been the desire to employ them as instruments of war that has most fostered their progress.
Very soon after Charles invented the gas balloon the latter was pressed into military service for the very same purpose of reconnaissance for which airships and aëroplanes are now being used. At the time of the French revolutionary war an aëronautical school was founded at Meudon under the control of Guyton de Morveau, Coutelle, and Conté, and a company was formed called Aërostiers.
Captive balloons were used by the armies of the Sambre and Meuse, of the Rhine and Moselle. Just before the battle of Fleurus, 1794, two ascents were made, and the victory of the French was attributed to observations made by Coutelle. At that time several ascents were made from Liége with a spherical balloon and one of cylindrical shape. This latter appears to have anticipated the well-known German kite-balloon.
There is a tradition that in those early days of the balloon the French were possessed of a varnish which satisfactorily held the hydrogen gas, but that the secret was lost—a grave loss indeed, if the tradition has truth in it. The secret was never refound. A really gas-proof varnish is unknown.
In the course of the American Civil War of 1861 captive balloons were again employed with important results.
During the Franco-Prussian War of 1870 three captive balloons were installed in Paris, the “Nadar” on the Place St. Pierre; the “Neptune,” manned by Wilfred de Fonvielle, at the gasworks at Vaugirard; and the “Celeste” on the Boulevard des Italiens.
Thus long before the advent of airships and flying machines the use of altitude for military reconnaissance was realised. A great disadvantage of the captive balloon was its stationary nature. It was not prudent to ascend in it very close to the enemy, as there was not the same chance of escape as when the aërial observer is in mobile aircraft.
Though rifle fire has over and over again failed to bring down a captive balloon owing to the upward pressure of the hydrogen gas, still, artillery fire has been known to have very destructive effect.
Undoubtedly, the best use that has been made of the captive balloon was in the Boer War. The British observation balloon equipment, which under the unceasing labours of Colonel Templer had reached a state of considerable perfection, then proved to be highly efficient. But in the light of modern aëronautical progress its doings were merely the foreshadowings of the achievements the aviators in the present war are daily carrying out.
Perhaps the most important feature of the balloons in the South African War was the material of which they were made—gold-beaters’ skin. We are all more or less familiar with this substance, for we use it as a plaster when we cut our fingers. We should scarcely think that so apparently fragile a substance was strong enough to form the envelope of a balloon. It is, however, an admirable substance for the purpose on account of its lightness and capacity of holding the gas, and the desideratum of strength can be obtained by combining layer and layer of the substance to any desired thickness. By the use of gold-beaters’ skin it became possible to have much smaller balloons for a given lifting power than when varnished cambric or silk was employed. If made of the latter materials a captive observation balloon had to be at least 18,000 cubic feet to be of any service. Gold-beaters’ skin reduced the volume to 10,000 cubic feet, or even less.
The only disadvantage of gold-beaters’ skin for the envelope of balloons and airships appears to be its very great expense. This, in the case of a large airship, is formidable. It should be mentioned, however, that it has sometimes been used for the separate gas compartments which, as will be seen, are a feature of the Zeppelin airship.
As regards the actual achievements of the balloon in South Africa, one section did excellent work at Ladysmith. In the words of Colonel Templer, “it not only located all the Boer guns and their positions, but it also withdrew all the Boer fire on to the balloon. Several balloons were absolutely destroyed by shell fire.”
One of the balloons was burst at a height of 1,600 feet, and came down with a very quick run, but the staff officer in the car was unhurt. At Ladysmith, by means of the balloon, the British artillery fire was made decisive and accurate.
With General Buller at Colenso, and up the Tugela River, Captain Philips’ balloon section was very useful. Splendid work was done at Spion Kop. There the whole position was located and made out to be impregnable. It has been said that the British Army was then saved from falling into a death trap by the aërial reconnaissance. Captain Jones’ section went up with Lord Methuen on Modder River. His observations continued every day. It was considered there was not a single day that they were not of the utmost importance.
Again, Lord Kitchener and Lord Roberts used balloons. From the information they obtained from them they were enabled to march on to Paardeburg. At the latter place itself they were able to locate the whole position. Another section went to Kimberley and on to Mafeking. A very important observation was made at Fourteen Streams. There a balloon was used continuously for thirteen days without the gas being replenished. By its means the Boers were prevented from relieving Fourteen Streams.
It has been pointed out by Colonel Templer that one of the great difficulties connected with the use of the comparatively small balloons in the South African War was the heights the armies went over.
On the march to Pretoria there were hills 6,000 feet above the sea, and to make an observation from these hills it was necessary to go up 1,500 or 2,000 feet, so that the barometrical height was hard work on the buoyancy of the balloon, because the barometrical height then became 8,000 feet—the 6,000 feet altitude above the sea-level, and the 2,000 feet it was necessary to go over the hills—that was about all our balloons would do.
That was a disadvantage of the captive balloons which would not have been felt if the observers had been on aëroplanes!
Certainly, the excellent gas retaining power of gold-beaters’ skin was well put to the test in the South African War. The thirteen days’ work with one charge of gas mentioned above was a fair trial for a balloon of such comparatively small size; but Captain H. B. Jones gave a still more striking experience of the value of gold-beaters’ skin as a gas-holder. Speaking of the Bristol war balloon of 11,500 cubic feet capacity, he says:—
It was used at the engagements at Vet River and Land River, and arrived at Kroonstad on May 12th. The balloon was kept in a sheltered place near the river till we marched again, on May 22nd, and was not emptied till after we had crossed into the Transvaal at Vereeniging on May 27th. To keep a balloon going for thirteen days at one station is a good test; but in our case the Bristol was filled for twenty-two days, and did a march of 165 miles with the division.
The system of filling the balloons from steel cylinders in which the hydrogen gas had been compressed, so well exemplified in the Boer War, was a great improvement on the older methods of manufacturing the gas on the spot. Speed in filling balloons is a desideratum for their use in war. By the cylinder method, owing to the great pressure under which the gas escapes from the cylinder, the inflation of the observation balloons became a question of minutes instead of hours. The necessity of speed applies to the inflation of airships also.
Although the present volume is designed rather to speak of the aëronautical appliances of the present than those of the past, the above-mentioned facts concerning aërial reconnaissance in the Boer War have been included, as the value of the air scouts at the time was hardly known and appreciated by the general public, whose mind in those days was not constantly being directed to aërial matters as it is at the present time. The knowledge of what just a few well-contrived and well-utilised balloons could then do in the way of aërial scouting must lead to the thought how the Boer War might have been shortened had we then possessed the squadrons of fast-flying aëroplanes that are taking part in the present war. To know, indeed, what a very few aërial observers could do may enhance our estimation of the possibilities of the squadrons of the flying machines of the British and allied armies in the present war as they dart in search of information over the lines of the enemy.
In the course of some articles on the subject of the new arm of war, which contain many apt statements, Mr. F. W. Lanchester gives the opinion that the number of aërial machines engaged in the war is a negligible quantity. We might, indeed, well say the more the better, provided they are on the Allies’ side; but no aëronaut or aviator will allow the number is negligible. The writer compares the supposed number of aëroplanes the Germans possess with the cost equivalent of scouting cavalry. The comparison is not a happy one, on account of the tremendous advantage of altitude and, consequently, long range of vision possessed by the aërial scout. We have seen that in the Boer War one observer at Spion Kop from his height and super-sight saved the situation, and rescued our army from possible crushing disaster.
What might not even one shrewd British observer in a swift-moving modern aërial craft accomplish at a critical moment in the present conflict?
CHAPTER II
THE DEVELOPMENT OF THE AIRSHIP
Before free balloons were successfully motor driven and steered, stern necessity had pressed them into the service of war. During the siege of Paris, in 1870, when the Parisians were cut off from all means of escape, there were only a few balloons in Paris; but the successful escape of some aëronauts in them was considered encouraging enough to establish an aërial highway involving a more wholesale manufacture of balloons than had been accomplished before. The disused railway stations were converted into balloon factories and training schools for aëronauts. In four months sixty-six balloons left Paris, fifty-four being adapted to the administration of post and telegraph; 160 persons were carried over the Prussian lines; three million letters reached their destination; 360 pigeons were taken up, of which only fifty-seven came back, but these brought 100,000 messages, by means of microphotographical despatches. In these a film 38 by 50 mm. contained 2,500 messages. The pigeons usually carried eighteen films, with 40,000 messages.
At this time the French Government attempted to produce a navigable balloon, and employed Dupuy de Lôme on the task of designing and building it. This was to be driven by hand power, the screw being driven by eight labourers. The balloon was actually made and tested. Considering the h.p. was 0.8, it is needless to say it was not successful.
It was during the siege of Paris that Krupp constructed the first special gun for attacking balloons, a relict which has been preserved at Berlin.
If such was the utility of balloons that merely drifted at the mercy of the aërial currents they encountered, it was not to be wondered at that, soon after the Franco-Prussian War, new attempts were made to make them navigable. Though the term airship might reasonably be applied to all the forms of navigable aircraft still in this country, it has been applied in a less wide sense to those machines that are lighter than air. In these pages the term will be used in this connection.
The effort to navigate balloons almost dates back to the invention of the balloon itself. It was, indeed, early realised that the spherical shape of the ordinary balloons that drift with the winds would be unsuitable for a craft that would have to travel against the wind. In 1784 Meusnier designed an elongated airship, in which the brothers Robert actually ascended. It is noticeable that in this early design of Meusnier was the now well-known ballonet, or inner balloon, which forms an essential feature of modern non-rigid and semi-rigid airships for preserving the rigidity of the outer envelope and facilitating ascent or descent.
If we except the effort of Dupuy de Lôme, the next remarkable attempt at airship construction was in 1852, when the Parisian Giffard made his steam-driven elongated balloon, with which he made two experiments. These merely proved that successful navigation against a wind would require much larger motive power than his Lilliputian steam-engine of 3 h.p. Giffard, however, was the pioneer of the airship driven by other than hand power. The following are the dimensions, etc., of what will ever be an historic balloon:—
| Length | 44 metres |
| Diameter | 12.00 metres |
| Cubic capacity | 2,500 cubic metres |
| Horse power | 3.0 |
| Estimated speed per hour | 6.71 miles |
The experiments of Krebs and Renard in 1885 were noteworthy. They were the first in which direct return journeys were made to the place whence the balloon started.
These experiments showed the importance of the military factor in the development of aërial navigation. Krebs and Renard were the officers in charge of the French Military Aëronautical Department at Meudon, and they applied national funds to the construction of an airship. It was the development of the electrical industry and the production of electric motors at that time which stimulated the experiments. The brothers Tissandier had, in 1883, propelled an elongated balloon against a wind of some three metres a second by means of an electric bichromate battery which supplied the power to an electric motor. It was thought that those experiments had been sufficiently successful for further trial of the powers of electricity.
Renard made profound and exhaustive researches into the science of the navigable balloon. To him we are, indeed, indebted for the elucidation of the underlying principles that have made military airships possible.
The navigable balloon “La France” was dissymmetrical, being made very much in the shape of a fish or bird. Its master diameter was near the front, and the diameters diminished gradually to a point at the back.
The following were the dimensions of the envelope:—
| Length | 50.40 metres |
| Diameter | 8.40 metres |
| Length in diameters | 6.00 metres |
The airship was remarkably steady on account of the minute precautions taken to counteract the instability produced by a somewhat excessive length. Any device which modifies pitching at the same time lessens the loss of speed resulting from the resistance of the air when the ship is moving at an angle. A direct means of reducing pitching is the dissymmetrical form given to the envelope by placing the master diameter near the front. The resistance of the air falls on the front surface, which in this dissymmetric form of envelope is much shortened, while the compensating surface at the back is augmented. Many experts are of opinion that in this form of envelope Krebs and Renard came nearer perfection than any other navigable balloon constructor.
Like the brothers Tissandier, they used an electric battery and motor to drive their screw, their motive power being 9 h.p.
It was claimed that out of seven journeys, the airship returned five times to the place whence it started. As an example of these journeys, on September 22nd, 1885, a journey was made from Meudon to Paris and back again. On this day the wind was blowing at a velocity of about 3.50 metres a second—what we should call a calm. Few, perhaps, who saw the small naval airship, the “Beta,” manœuvring over London this autumn realised that a navigable balloon, not so very much unlike it in form, was speeding its way over Paris as long ago as 1885. The advent of the first at all practical military airship was forgotten because the experiments, comparatively successful as they were, suddenly ceased. They came to an end because it was found that though electricity as a motive power could afford an airship demonstration, it was unfitted for serious and prolonged use.
One industry has often to wait for another—the world had to wait for the missing link in aërial navigation. That was the light petroleum motor. With its coming came the era of airships and aëroplanes.
CHAPTER III
TYPES OF MODERN AIRSHIPS
With the new century came the modern military airship—to stay, at any rate, until the heavier-than-air principle of aërial navigation has so developed as to absorb those features of utility the airship has and the aëroplane has not.
During the fourteen years which have seen the construction of practical airships, three distinct types have been evolved—(i.) rigid, (ii.) non-rigid, (iii.) semi-rigid. In considering the airships of Great Britain, France, and Germany, I propose to class them together as to types rather than under nationalities.
Each type has its own peculiar advantages. The choice of type must depend upon the circumstances under which it is proposed to be employed.
Top: SNAPSHOT OF ZEPPELIN IN MID-AIR.
Centre: MILITARY LEBAUDY AIRSHIP, showing fixed vertical and horizontal fins at the rear of gas-bag, vertical rudder, and car suspended from rigid steel floor underneath gas-bag.
Bottom: CAR OF A LEBAUDY AIRSHIP, showing one of the propellers.