Fig. 68.—An Avro Sea-Plane.A. Propeller; B. 100-h.p. Gnome motor, hidden by shield; C.C. Main-planes; D. Observer’s seat; E. Pilot’s seat; F. Rudder; G. Elevating-plane; H. Float to support tail; I. Main floats to bear the weight of the machine.
Fig. 68.—An Avro Sea-Plane.
A. Propeller; B. 100-h.p. Gnome motor, hidden by shield; C.C. Main-planes; D. Observer’s seat; E. Pilot’s seat; F. Rudder; G. Elevating-plane; H. Float to support tail; I. Main floats to bear the weight of the machine.
The sea-plane, when a flight is made, is launched upon the water down a slipway; then the pilot and his passenger embark, the motor is started, and the propeller draws the machine across the water at a rapidly increasing pace. The floats raise themselves higher and higher upon the water, as the air-planes exercise a growing lift, until they only just skim the surface. And now comes the moment when the airman, drawing back his elevating lever, seeks to raise his craft from the water into the air. At first only the front of the floats rise, the rear sections clinging to the surface; then, in another instant, the whole float frees itself from thewater in a scatter of spray, and the craft glides at a gently-sloping angle into the air. It is the aim of builders, by the curve they impart, to make the floats leave the water with as little resistance as possible. In the floats of the Avro (Fig. 68) will be noticed a notch, or cut-away section, which occurs at about the centre of the float upon its lower side. This is called a “step,” and is to help the float to lift from the water. When the main-planes draw upward, as the craft moves prior to its flight, the floats tend, as has been said, to raise themselves in the water; and as they do so, lifting first towards the bow, there comes a space between the upward-cut “step” and the surface of the water. Into this space air finds its way and, by helping still further to free the float from the surface, aids greatly at the moment when the pilot—operating his hand-lever—seeks the final lift which will carry him aloft.
When in flight, as when skimming upon the surface of the water, a sea-plane must carry its floats with it; and this introduces a complication, inasmuch as the floats offer a resistance to the air and tend to reduce speed. Another need is thus shown; the builder of a float must so shape it that it will move through the air with the least possible friction. This is accomplished by making it long and tapering in form and by curving and polishing its surface.
England, in the building and handling of sea-planes has come well to the fore, and our machines are more advanced than those of other countries. The Admiralty has recognised that, acting as a coastal scout in time of war, such craft would be of the utmost value; thus we find air-stations dotted round our seaboard, from whichmachines may fly in a regular patrol. By the employment of hundreds of craft, operating upon a well-ordered plan, it will be possible in the future to girdle our shores completely; and such machines would not only spy out the approach of an enemy’s fleet, but give battle to hostile aeroplanes or airships which might seek to pass inland. The type of machine we have just described was a biplane, but there are monoplane sea-craft, and a Bleriot fitted for alighting upon the water is shown inFig. 69.
Fig. 69.—A Bleriot Sea-plane.
Fig. 69.—A Bleriot Sea-plane.
Another form of craft is being developed successfully—the flying boat. This is not merely a land aeroplane with floats instead of wheels; it is a boat with a sea-going hull, which has lifting planes upon it; and it assumes the distinctive form seen inFig. 70. When on the surface of the water the machine floats like a ship; then, when driven rapidly across the surface, its planes raise it into the air and it flies. A closer view of the hull of such a craft is given inFig. 71.
Flying boats are at present small and lightly built, and they have difficulty in weathering rough waves when floating upon the water; but already the tendency is to make them larger, and to give them more powerfulmotors, and such machines for naval work, as developed in the future, may be as large as a torpedo-boat-destroyer and capable of high speeds both on water and in the air.
THE MACHINE SEEN FROM ABOVE,showing the shape of wings and tail, and the positions of the pilot and passenger within the hull.
THE MACHINE SEEN FROM ABOVE,showing the shape of wings and tail, and the positions of the pilot and passenger within the hull.
A. Hull; B. seats for crew; C.C. Planes; D. Motor; E. Propeller; F. Rudder; G. Elevators.
A. Hull; B. seats for crew; C.C. Planes; D. Motor; E. Propeller; F. Rudder; G. Elevators.
MACHINE SEEN FROM IN FRONT,showing the span of the main-planes, and the curve of the boat-shaped hull.Fig. 70.—A Flying Boat.
MACHINE SEEN FROM IN FRONT,
showing the span of the main-planes, and the curve of the boat-shaped hull.
Fig. 70.—A Flying Boat.
Fig. 71.—The hull of a Flying-Boat.A. Pilot’s seat and controlling wheel; B. Passenger’s seat; C. Movable flap to facilitate entering the hull; D. Handle, like that of a car, for starting the engine; E. The engine; F.F. Fuel tanks; G. The propeller.
Fig. 71.—The hull of a Flying-Boat.
A. Pilot’s seat and controlling wheel; B. Passenger’s seat; C. Movable flap to facilitate entering the hull; D. Handle, like that of a car, for starting the engine; E. The engine; F.F. Fuel tanks; G. The propeller.
There is another type of craft that is being adapted and improved for naval use, and this is the airship. Although it is costly to build, requires a huge shed in which to house it, and needs also the service of trained crews to handle it when ascending or alighting, the airship is a vastly importantmachine for the purposes of war. Its ability to make flights lasting several days, and the power of its pilot to manœuvre it at night, render it particularly suitable for naval use. Our Admiralty is buying large machines, aiming at a preliminary fleet of fifteen, and the German Navy is organising a squadron of Zeppelins.
The airship, although in use before the aeroplane, has developed more slowly, and is even to-day in a crude form. This has been due to the cost of experiments. Whereas a new aeroplane may be built and tested for £1000 or so, the construction of an airship and the provision of its shed spells an expenditure of many thousands. This money may, as in the case of theaeroplane, be lost as a result of one mishap. In Germany Count Zeppelin spent a fortune upon airships, before the Government and the nation helped him with funds. With very few exceptions, none but Governments—which have long purses to draw upon—can afford to build large airships.
Fig. 72.—A modern Balloon.
Fig. 72.—A modern Balloon.
The airship is a development of the balloon; and the balloon we owe to Stephen and Joseph Montgolfier—two French brothers who, after watching clouds floating in the sky, had the notion that if they could fill a light envelope with “some substance of a cloud-like nature” it would raise itself into the air. Their father was a paper manufacturer, and so they had facilities for making a number of very large paper bags. Under these they lit fires of chopped straw, allowing the hot air and smoke to rush up into the bags, and, when they were released the bags ascended, carried up by the lifting influence of the heated air within them. Thus was invented the hot-air balloon; and we buy paper replicas of it to-day.
Delighted with their first success, the Montgolfiers built a paper balloon 30 ft. in diameter, and this was sent up at Annonay, in France, on 5th June 1783. It flew for ten minutes before the heated air inside it became cold, and reached a height estimated at more than a mile. After this came the ascent of a spherical balloon—one, that is to say, the shape of a modern-type balloon. It was made of linen, covered with paper, and had a small car attached. At Versailles, in France, on 19th September 1783, this balloon was sent up with passengers in the car; not human beings, though, for no man cared to ascend, fearing that the upper atmospheremight have some strange effect upon him. The actual occupants were a sheep, a cock, and a duck; and these three unwilling voyagers made a flight which lasted eight minutes. When they descended the sheep and the duck were found to be unharmed, although greatly perturbed; but the cock showed symptoms of not being well! At first, when learned men examined him, it was thought the rarefied atmosphere had in some way affected him, and this view was held until practical folk were able to show that the bird had been trampled upon by the sheep.
From this, of course, the next step was the ascent of a man, and on 15th October 1783 an adventurous youth named Pilatre de Rozier went up in a balloon built by the Montgolfiers. The balloon was attached to a rope and not allowed to ascend more than 100 feet; and at this altitude the aeronaut remained for about four minutes. A month later de Rozier and a passenger—the Marquis d’Arlandes—were bold enough to risk a flight in a Montgolfier balloon. This time the ascentwas made from Paris, and the balloonists flew for five minutes before descending, reaching a height of 500 feet.
Fig. 72a.—The car of a modern Balloon.A.A. Ballast bags filled with sand; B. Instruments (such as a statoscope, which shows at any moment whether the balloon is rising or falling; and an altitude meter); C. Ring by which car is attached to balloon.
Fig. 72a.—The car of a modern Balloon.
A.A. Ballast bags filled with sand; B. Instruments (such as a statoscope, which shows at any moment whether the balloon is rising or falling; and an altitude meter); C. Ring by which car is attached to balloon.
Coal-gas superseded hot air in the filling of balloons, the latter being unsatisfactory, seeing that it cooled rapidly and allowed the balloon to descend; the only alternative being to do what some of the first aeronauts did, and burn a fire below the neck of their balloon even when in the air. But the dangers of this were great, seeing that the whole envelope might easily become ignited. With balloons filled with coal-gas—modern examples of which are seen in Figs.72and72A—long flights were possible, but they had always this disadvantage—the voyagers were at the mercy of the wind, and could not fly in any direction they might choose. If the wind blew from the north then they were driven south, the balloon being a bubble in the air, wafted by every gust. Aeronauts became disgusted with this inability to guide the flight of a balloon, and many quaint controls were tested; such, for example, as the use of a large pair of oars with which theballoonist, sitting in the car of his craft, rowed vigorously in the air. But this method found little favour; and it was followed in due course by the use of small steam engines and electric motors, which were made to turn propellers such as are used in aeroplanes. For such experimental craft, the rounded form of gas-container was abandoned and a cigar-shaped envelope adopted, pointed at both ends, which could be more easily driven through the air. An airship of a crude and early type is seen inFig. 73. It was built by an experimenter named Gifford, and in 1852 it flew at the rate of seven miles an hour.
Fig. 73.—An Experimental Airship.A. Gas-containing envelope; B. Car suspended below envelope, which carried the aeronaut and a 3-horse-power steam engine; C. Two-bladed propeller driven by the engine; D. Rudder (in the form of a sail) by which the machine could be steered from side to side.
Fig. 73.—An Experimental Airship.
A. Gas-containing envelope; B. Car suspended below envelope, which carried the aeronaut and a 3-horse-power steam engine; C. Two-bladed propeller driven by the engine; D. Rudder (in the form of a sail) by which the machine could be steered from side to side.
When petrol engines became available, they gave an impetus to the building of airships; for, like the aeroplane, the airship needed a motive agent which gives a high power for a low weight. One of the first to use a petrol motor in an airship with success was M. Santos-Dumont, whose name has been mentioned in connection with aeroplanes. He tested small, light airships, driven bypetrol engines and two-bladed propellers—as illustrated inFig. 74; and with one of these, on a calm, still day, he flew over Paris and round the Eiffel Tower.
Fig. 74.—Santos-Dumont’s Airship.A. Gas envelope; B. Wheeled framework which carried motor, propeller, and pilot’s seat; C. Elevating-plane; D. Horizontal rear-plane; E. Rudder.
Fig. 74.—Santos-Dumont’s Airship.
A. Gas envelope; B. Wheeled framework which carried motor, propeller, and pilot’s seat; C. Elevating-plane; D. Horizontal rear-plane; E. Rudder.
Then by degrees came larger craft, more powerfully engined, and built to attain greater speed. Hydrogen, far more buoyant than coal-gas, was used to inflate their envelopes, and so they obtained a greater “lift.” Speed with the airship was recognised as vital. If it could not fly fast it was at the mercy of the wind, gusts striking powerfully against its envelope, and driving it off its course.
Fig. 75.—Early-type Airship.A. Gas envelope; B. Car suspended below envelope; C. Motor, which drives propeller (D) through a shaft; E. Small horizontal plane for rising or descending; F. Fixed fin, or keel plane, to give stability; G. Rudder.
Fig. 75.—Early-type Airship.
A. Gas envelope; B. Car suspended below envelope; C. Motor, which drives propeller (D) through a shaft; E. Small horizontal plane for rising or descending; F. Fixed fin, or keel plane, to give stability; G. Rudder.
Fig. 76.—Airship “ballonette.”A. Gas envelope; B. The interiorballonette, or collapsible chamber,which is filled with airthrough the pipe C.
Fig. 76.—Airship “ballonette.”A. Gas envelope; B. The interiorballonette, or collapsible chamber,which is filled with airthrough the pipe C.
A typical craft, representing the first of those navigated with any certainty, is shown inFig. 75. A gas-containing envelope, made of a light, strong, varnished fabric, is kept taut by the pressure of the gas within; the car, constructed of wood or metal tubing, is suspended by ropes from the envelope, and contains engine and crew, with a two-bladed propeller revolving astern. Such a machine, in its control, had an elevating-plane and rudder, upon the same principle as those of the aeroplane. One of the difficulties to be overcome was the expansion and contraction of gas in the envelope owing to differences in altitude and temperature. When the craft ascended, its envelope completely inflated, the gas began to dilate owing to the outer air becoming less dense; and some had to be allowed to escape through automatic valves. Then, should the machine descend to a lower level, there was not sufficient gas in the envelope to keep it tightly stretched, and it tended to sag at the bow as it was driven through the air. To prevent this kinking, which would have reduced the speed of the airship, and made it difficult to control, an interior chamber, called the “ballonette,” was fitted to the envelope, as shown inFig. 76. When the gas-container was tightly filled, this ballonette lay empty upon its lower surface; but, should the envelope tend to become flaccid, through a loss of gas, a fan pumped air into the ballonette; and, swelling out within the balloon, it compensated for the gas which had escaped, and prevented the envelope from losing its shape.
The craft shown inFig. 75is of the non-rigid type; its car, that is to say, is hung by ropes from the envelope; and when the envelope is deflated it can be detached from the car and the machine packed away in a relatively small space. But as airships were built larger, andgreater speeds were obtained, it became necessary to strengthen the envelopes with some form of keel; and this led to a type which is known as the semi-rigid, and is developed successfully in France.Fig. 77illustrates an airship of this build. Along the lower side of its envelope is placed a light, rigid framework or keel, and from this is suspended the car which contains engines and crew.
Fig. 77.—Semi-rigid Airship.A. Gas-containing envelope; B. Strengthening keel; C.C. Stabilising-planes; D. Rudder; E. Car carrying engines, propeller, and crew.
Fig. 77.—Semi-rigid Airship.
A. Gas-containing envelope; B. Strengthening keel; C.C. Stabilising-planes; D. Rudder; E. Car carrying engines, propeller, and crew.
The car of an airship, showing its construction and the disposition of motors and propellers, is sketched inFig. 78; while inFig. 79may be seen the pilot’s driving platform with wheels, dials, and speaking-tube to the engineers.
Fig. 78.—The Car of an Airship.A.A. Propellers; B. Motors; C. Engineer’s platform; D. Pilot’s controlling platform; E. Elevating-planes; F. Fuel tanks; G. Passenger’s platform.
Fig. 78.—The Car of an Airship.
A.A. Propellers; B. Motors; C. Engineer’s platform; D. Pilot’s controlling platform; E. Elevating-planes; F. Fuel tanks; G. Passenger’s platform.
Fig. 79.—Control platform of an Airship.A.A. Wheels operating elevating-planes and rudder; B. Height recorder; C. Speaking-tube to communicate with engineers.
Fig. 79.—Control platform of an Airship.
A.A. Wheels operating elevating-planes and rudder; B. Height recorder; C. Speaking-tube to communicate with engineers.
Fig. 80.—Hull of a Zeppelin during construction.
Fig. 80.—Hull of a Zeppelin during construction.
Craft of the semi-rigid type provide a link betweensmall, non-rigid ships and the very large machine which is built with an entirely rigid framework, and has its example in the Zeppelin. The maker forms a skeleton hull of aluminium or some light metal alloy, a method that is shown inFig. 80. The hull of a Zeppelin, slightly more than 500 feet in length, is sheathed with tightly stretched fabric; and within it are the gas-containers—a row of seventeen separate balloons, each in a compartment by itself, and containing a total of nearly 1,000,000 cubic feet of gas—which give these airships a lifting power of close upon 30 tons. The arrangement of the gas-holders, and the general outline of the machine, may be observed fromFig. 81. The vessel offers comparatively little resistance to the air, despite its size, and this is due to the finely tapering shape of the hull; while its rigidity allows it to be driven at speeds of more than 50 miles an hour. The lifting capacity, also, enables long flights to be made. Taking up crew and petrol, such a craft can remain aloft for several days, and travel distances of more than 1000 miles.
Fig. 81.—A Zeppelin Airship.A.A. Rigid hull covered by fabric; B. Section showing the skeleton framework of hull; C. Arrangement of the interior gas chambers; D. Elevating-planes; E.E. Rudders; F.F. The two cars containing engines and crew; G. Passage-way between the cars; H. One of the propellers, of which the craft has four—two at the front of the hull, upon either side, and two at the rear.
Fig. 81.—A Zeppelin Airship.
A.A. Rigid hull covered by fabric; B. Section showing the skeleton framework of hull; C. Arrangement of the interior gas chambers; D. Elevating-planes; E.E. Rudders; F.F. The two cars containing engines and crew; G. Passage-way between the cars; H. One of the propellers, of which the craft has four—two at the front of the hull, upon either side, and two at the rear.
At first, flying slowly and with unreliable motors, these very large airships were at the mercy of the wind, particularly when manœuvring near the ground. Trained crews were necessary to handle them, and they had to be housed in huge and expensive sheds, as will be realised from a glance atFig. 82. But for the one ardent pioneer, Count Zeppelin, it is doubtful whether large, rigid craft would have been built at all. After costing many thousands, they ran the risk of being dashed to earth in a squall and hopelessly wrecked. Such a fate, indeed, befell one ship after another that Count Zeppelin launched. But he refused to be discouraged, and went on doggedly until his private fortune was gone. Then, magnificent flights having been made, the Government came to his aid; while the German people, immensely proud of his achievements, subscribed more than £300,000 for the furtherance of his tests. And so now the Zeppelin—powerfully engined, better built, and handled by expert crews—is the Dreadnought of the German air-fleet, flying hundreds of miles over the North Sea, co-operating with warships as a scout,and flashing messages by wireless for distances of 300 miles.
Fig. 82.—An Airship leaving its shed.A. The machine emerging stern first; B. A sister craft in dock; C.C. The launching crews; D.D. Rails upon which the cars of the airship move, so as to prevent its swinging sideways in a gust; E. Outlook station upon the roof of the shed; F. Workshops; living quarters for the crews; plant for making hydrogen gas.
Fig. 82.—An Airship leaving its shed.
A. The machine emerging stern first; B. A sister craft in dock; C.C. The launching crews; D.D. Rails upon which the cars of the airship move, so as to prevent its swinging sideways in a gust; E. Outlook station upon the roof of the shed; F. Workshops; living quarters for the crews; plant for making hydrogen gas.
The airship, for long-distance reconnoitring, stands at present unrivalled. It can remain in the air for days, sweeping over sea or land, and reporting constantly to its headquarters. For night flying, also, it is at present the superior of the aeroplane, being navigable in darkness, and having an ability to hover above a given spot, its engines silent, and its presence undetected by those below.
Guns and bomb tubes—Launching a plane from a ship at sea—Transporting troops by aeroplane—Battles in the air.
Nations, in their preparations for war, make a succession of moves and counter-moves. For instance, a torpedo-boat is perfected; immediately it is launched, and ready for its deadly rôle, a larger and swifter craft is built which may sink it or chase it off the seas. A huge battleship, supreme in its might to-day, is eclipsed to-morrow and made to appear obsolete.
Photo, “Central News.”PLATE XII.—THE LONDON AERODROME FROM ABOVE.This photograph, taken by a passenger in a Grahame-White biplane, gives an excellent idea of the view that may be obtained from a machine in flight. Another aeroplane is flying past the enclosures, and there is a Midland railway train in the distance.
Photo, “Central News.”
PLATE XII.—THE LONDON AERODROME FROM ABOVE.
This photograph, taken by a passenger in a Grahame-White biplane, gives an excellent idea of the view that may be obtained from a machine in flight. Another aeroplane is flying past the enclosures, and there is a Midland railway train in the distance.
As soon as they became reliable, and could be used in war, aeroplanes and airships were pressed into service as scouts—their task being to ascend, spy out the land below, and return with news to their starting-points. That was the first conception of their use, and War Departments looked no farther. But when machines were built in numbers, and air fleets began to form, strategists saw the complications that would ensue. If A has a fleet of aircraft and B also, and A and B are at war, then the aim of each will be to hamper the other’s air-scouts, and destroy them whenever possible. Here, again, is the theory of move and counter-move. The air-scout, flying above an army, may see its secret at a glance; therefore steps must be taken to keep him off, to drive him away, to blow him to pieces and all of his kind.
This may be done with a cannon from the ground, but the method is not certain. Special guns have been built which will point into the air, can be sighted quickly, and will fire a shell to a great height. If an aircraft comes within range of them, and the gunner has time to aim correctly, a bursting shell may bring the machine to ground. But there are the “ifs” to be remembered. The scout—favoured by a clear day and using his own judgment—may be able to do his spying without venturing within range of a land gun; and, even should he come into firing distance, he may be shot at and missed. Such guns are valuable, of course—mounted upon motor-cars for speedy transport from place to place, and used also to guard fortifications, and against aerial foes by a ship at sea.
Other guns are possible, besides those which fire shells. Attention has been directed to the feasibility of using a form of vortex-gun. This is a weapon rather like a huge air-gun. It compresses a charge of air and discharges it at a high velocity in a whirling vortex or ring. This, invisible but immensely destructive, strikes its target like a cyclone, and has been known—even with the use of an experimental gun—to tear up fences at a distance of several hundred yards. If such a gun was discharged at an aircraft, and the aim was accurate, it is argued that the machine would be hurled over and wrecked by the force of the artificial hurricane.
But something more than a land gun is necessary to fight this new foe—something more certain; it must, in a word, be sought and attacked in its own element, the air. There are two ways at present in which aircraft can engage each other; one machine may rise above its adversary, and drop bombs upon it, or two craft may seek to cripple each other by a fire from machine-guns. Other and more deadly methods are discussed, and may even be employed. Attacking an airship, for instance, a man might ascend in a fast monoplane and charge directly at his bulky foe; then, just before the impact, he might spring from his machine and descend by means of a parachute, leaving his empty craft to crash into the airship and cut a gash through its hull. Many things may be done, in fact, when aerial war is faced; but as tactics are now discussed, and plans made, machine-guns and bombs are the weapons reckoned feasible.
When one imagines two craft manœuvring for position, and about to engage in a duel in the air, speed would seem a vital need; and here, when opposed to the airship, an aeroplane has advantage. But airships are being built larger and faster in flight; and the speed of an aeroplane, when it has to carry the burden of a gun, is lessened perceptibly; added to which is the fact that, owing to its weight-lifting capacity, the airship can raise a heavier type of gun. The airship may be likened to the battleship of the sky, and the fighting aeroplane to a cruiser; and it seems likely that, in actual warfare, several of the latter will be detailed to attack an airship.
Already, anticipating war in the air, a fighting aeroplane has been evolved; and a machine of this type is shown inFig. 83. The body, in which pilot and gunnersit, is armoured lightly with plates which will resist the penetration of a bullet. Such armouring was found necessary after the use of aeroplanes in Tripoli and the Balkans. When flying unavoidably low in these campaigns, and when fired at from the ground, the wooden bodies of machines were pierced by shot, and in several instances their occupants wounded.
Fig. 83.—A Fighting Aeroplane (the Vickers’).A. Machine-gun projecting from opening in bow; B. Gunner’s position; C. Pilot’s seat; D.D. Side windows for observation; E. Engine and propeller.
Fig. 83.—A Fighting Aeroplane (the Vickers’).
A. Machine-gun projecting from opening in bow; B. Gunner’s position; C. Pilot’s seat; D.D. Side windows for observation; E. Engine and propeller.
Fig. 84.—Bomb-releasing mechanism.A. Lower part of aeroplane’s hull;B. Revolving barrel to which bombs are clipped;C. Bombs; D. Releasing mechanism operatedby marksman in machine.
Fig. 84.—Bomb-releasing mechanism.A. Lower part of aeroplane’s hull;B. Revolving barrel to which bombs are clipped;C. Bombs; D. Releasing mechanism operatedby marksman in machine.
The fighting aeroplane sketched is an experimental machine—as are all those built at present for aerial war. It carries no very powerful gun, and is not the formidable craft the future will evolve; but it would have, none the less, a definite value in time of war. When used with an army in the field it would drive off an enemy’s scouts, attack armed and hostile craft, and harass and cripple an airship should it chance to meet one. It need not rely solely upon its gun. Bombs may be carried and dropped when opportunity offers; and as an improvement upon the early method, which was simply to throw these from the machine, there are releasing mechanisms now devised which carry a number of projectiles and drop them oneby one as a lever is moved (seeFig. 84). The bombs, which are long, pointed, and balanced so that they will fall head first, are clipped round a barrel rather like that of a revolver, which is fixed beneath the aeroplane’s hull just below the occupants’ seat. Mechanism causes the carrying chamber to revolve and bring each bomb against a releasing catch, which—at a movement of the marksman’s lever—throws it outwards and downward.
Bomb-sighting instruments are now being tested, so that a pilot may drop a missile with accuracy upon a given spot. In the early experiments, when a pilot merely leaned forward as he flew, bomb in hand, and guessed his aim, the majority went wide of their mark. Several factors enter into this problem of aim. There is the speed of the machine, its height above the ground, and the question whether a wind may affect the fall of the bomb. Dropped haphazard, a bomb is unlikely to reach its mark. In sighting instruments now provided the marksman finds his altitude, estimates his speed by the time his craft takes to pass between two points on the land below, and then makes an allowance for side-drifting owing to the influence of the wind.
Bombs of many types are being made. Some weigh about 10 lbs., and are filled with several pounds of anextremely high explosive. Others are what is known as incendiary bombs; when they strike an object they burst into flames, and are intended to cause fires on the roofs of buildings or supply stores. A single aeroplane, dropping bombs in war, would not be likely to have much effect; but the plan will be to equip squadrons of these machines, their crews trained to sweep in unison over the point attacked, and rain down bombs in a ceaseless and destructive stream.
There is a risk for airmen when they carry a load of explosives. Should they make a bad landing, or fall to the ground and wreck their craft, there is the probability that their bombs would explode from the impact and blow them to pieces. This danger has been realized, and a form of safety bomb is now being used in tests. Each bomb is fitted with a safety catch, and unless this is released the bomb cannot explode, no matter how hard it strikes the ground. The manner in which the catch disengages itself is ingenious. Upon the rear of the bomb is a tiny propeller, which spins in the air as the bomb drops from the machine; and as it turns it uncoils a spring, which releases the safety catch and makes the bomb operative—but not until after it has fallen about 100 feet.
Airships, like aeroplanes, are being armed with guns and bombs; and their power of raising weights enables them to carry heavy weapons. Large and highly destructive bombs have been tested in the German airships, being released over the sea and aimed at targets in the form of rafts. Latest-type airships also carry guns in their cars; and the Zeppelins have a platform upon the tops of their hulls, reached bya ladder through the middle of the ship, from which a machine-gun can be fired upward. This is a very necessary precaution, and is intended to frustrate the attack of an aeroplane. It would be the aim of the latter, whenever possible, to manœuvre above its big enemy—as suggested inFig. 85—and drop a bomb upon its hull. Hence the construction of the top platform of the airship, from which her gunners can direct a vigorous fire aloft.
Fig. 85.—Aeroplanes attacking an airship from above.
Fig. 85.—Aeroplanes attacking an airship from above.
The ability of an airship to navigate at night, and steal unobserved above the land, gives it grim possibilities as a weapon of destruction. It motorsquiet, and no lights showing, it can drift with the wind over a harbour or fortification, and drop bombs which will fall upon those below out of an empty sky. Searchlights would be used, of course, from the positions attacked, and artillery fired upward, but the airship would be a silent, elusive shape—difficult to see and more difficult to hit.
Here, though, would be work for land or sea planes. It would be the aim of our Admiralty, upon the outbreak of war, to patrol the coast with a service of armed aircraft. A number of air-stations, at which machines are housed, are already in existence—mainly along the north-east coast. Between station and station the craft would fly in war, providing a continuous patrol, the aim being to shut out hostile craft, and attack a squadron of the enemy, should it approach land.
The observer in a sea-plane, under favourable conditions, can also detect the movements of a sub-marine, his height above the water enabling him to see beneath its surface and discern the shape of the vessel, even when it is submerged. This would be of value in war, as proved in manœuvres with our fleets. A sea-plane, patrolling the entrance to a harbour, can send a warning by wireless should hostile submarines—invisible to all save the aerial watcher—seek to steal in upon a destructive raid.
The air-patrol would play its part, too, if an enemy attempted to land troops. Flying above transports as they neared the coast, the planes would drop bombs upon them. Many of the patrols, also, would be equipped with wireless, and would scout in searchof an enemy’s fleet, reporting constantly to the land stations as they flew.
Fig. 86.—Sea-plane to carry a crew of seven.A. Hull upon which the machine floats when in the sea; B.B.B. Wheels upon which it may move when on land, and which fold upward when it is on the water; C. Pilot’s controlling wheel; D.D. Main sustaining planes; E. Four-bladed propeller driven by chain-gearing from engine within the hull.
Fig. 86.—Sea-plane to carry a crew of seven.
A. Hull upon which the machine floats when in the sea; B.B.B. Wheels upon which it may move when on land, and which fold upward when it is on the water; C. Pilot’s controlling wheel; D.D. Main sustaining planes; E. Four-bladed propeller driven by chain-gearing from engine within the hull.
A coastal sea-plane, as now planned, is a craft having, say, two engines, each devolving 120 h.p., with a wing span of some 80 feet, and an accommodation in its hull for three men—the pilot, a combatant with a machine-gun, and an observer with an installation of wireless. But types are changing constantly, and the tendency is to build larger craft. A machine weighing a couple of tons is shown inFig. 86, and a novelty in regard to it is that it has wheels upon either side of its boat-shaped car, upon which it canmove on land, and which fold upward when it rests upon the water.
Long flights over-sea, in search, say, of the assembling point of an enemy’s fleet, would be undertaken by the naval airships. They will be relied upon, for example, to scour the North Sea by day and night; and, poised high above the water, they would be able to locate an enemy’s fleet when at an immense distance.
There is a type of aeroplane which will be carried to sea when a fleet sails, stowed in sections within the hull of a transport ship. This machine—a light, high-speed craft—will be assembled upon the deck of its parent ship, and launched into the air by special mechanism, as there is not room for a machine to run upon wheels, and leave the ship’s deck as it might do upon land; the vessel, besides, might be rolling in a high sea. In some cases a platform is built upon the deck, either at the bow or stern, and along this the aircraft moves, so as to gain speed for its planes to lift. In one device, seen inFig. 87, the machine is mounted upon a light wheeled cradle, and this is placed upon the starting-rail. Then, driven by its propeller, the plane runs forward upon the cradle till it reaches the end of the rail, when it glides into the air, the cradle falling from it and dropping into the sea, from which it is retrieved and drawn back on board the ship. By another method, shown inFig. 88, the sea-plane is launched from a cable suspended between two masts, and can come to rest upon the cable again after a flight has been made. The machine is hung upon the cable prior to making an ascent; then the pilot starts his engine, and as his machine glides forward along the cable he releases a catch and soars into the air. Upon returning he fliesbeneath the cable, and makes his craft rise until the “V”-shaped apparatus above his head is caught by the cable and the catch becomes operative; then he stops his motor, and his craft hangs from the cable as it did before.
Fig. 87.—Launching sea-planes from a ship’s deck.The sea-plane (A.) is seen taking flight, having glided upon its cradle along the platform (B.). The cradle (C.) is just falling away below the aircraft’s hull.
Fig. 87.—Launching sea-planes from a ship’s deck.
The sea-plane (A.) is seen taking flight, having glided upon its cradle along the platform (B.). The cradle (C.) is just falling away below the aircraft’s hull.
A. Sea-plane; B.B. Cable; C. The “V”-shaped apparatus which guides the cable into the clip (D.) and so suspends the machine from the wire.Fig. 88.—Launching a sea-plane from a wire.
A. Sea-plane; B.B. Cable; C. The “V”-shaped apparatus which guides the cable into the clip (D.) and so suspends the machine from the wire.
Fig. 88.—Launching a sea-plane from a wire.
A flying scout, operating with a fleet at sea and rising from the deck of a ship, would be of very distinct value. When approaching an enemy he would be sent aloft to reconnoitre, and would locate hostile craft before men could see them from the ships below. The utility of such a scout is proved by the lessons of history. On one occasion, for instance—it was in 1805—Nelson was waiting to intercept a French fleet at Toulon. But they managed to steal out unobserved, and Nelson chased them to the West Indies before he caught them. If he had had an aeroplane to send up and keep watch, he would not have missed his enemy.
The air-scouts of a fleet would note also the approach of airships, and could spy upon harbours or fortifications when an attack was being made upon them from the sea.
At present, it must be remembered, the possibilities of an air-fleet are vague—all at least save one; and that is the utility of an airship or plane for scouting. The value of aircraft in this direction has been proved, not only in peace manœuvres but in war; but as to what destructive work an aeroplane can accomplish, or how machines will fight when they meet in mid-air, there is only theory for a guide. That an aircraft may carry explosives, and drop them with accuracy, is now an established fact; also that a machine-guncan be mounted upon a machine, and fired successfully at a target while the craft is in flight. But no country, as yet, has equipped itself with a squadron of fighting aeroplanes. For one thing, owing to the fact that powerful aviation motors are only just becoming available, craft are still small in size; and this limits them to the carrying of a light gun. What is wanted, and what will be built in time, is a large, armoured, high-speed craft, having more than one engine, carrying a crew, and being able to bear the load of a powerful gun. In war, had a Commander a squadron of such machines, he would use them for attacking an enemy’s supply stores and ammunition parks, for blowing up railway lines, and for harassing troops when they were on the march; and he would launch them, of course, when necessary against hostile aircraft which might approach his own lines.
In the first instance, in the case of a great war, there will be a battle in the air; and how severe this will be must depend upon the strengths of the air-fleets opposed to each other. Command of the air, like command of the sea, will be all-important. If one Commander-in-Chief can cripple and disorganise his opponent’s air-fleet, it will be like blinding his enemy. He himself, still well served by his air-scouts, will note all the movements of his enemy; but this enemy, with an air fleet driven back, and most of its machines disabled, will be enveloped in what has been called “the fog of war”; he will glean no more as to his enemy’s tactics, that is to say, than can be obtained by cavalry or foot scouts.
Not only the fighting aeroplanes, but the generalequipment of the air-fleet, will play a part in the aerial battles of the future. Surprisingly intricate, and little known, is the organisation of a squadron of war machines. There must be trained mechanics in large numbers, and they must be driven from place to place in motors, according to the movements of the machines they serve. Then the aeroplanes, if necessary, must be packed on lorries and taken across country by road; and there must be portable sheds upon the landing grounds, in which they may be housed at night. There needs to be an equipment of spare machines also; and a number of travelling workshops with skilled engineers, which can be rushed from place to place for the repair of damaged craft. A sketch of one of these workshops on wheels, which are vital to the organisation, is seen inFig. 89.