France was stronger in airplanes but weaker in dirigibles. Of the former she had about 1500; of the latter not more than twenty-five.

The land was swept for planes in the hands of private owners and, as the French people had from the first taken a lively interest in aviation, more than 500 were thus obtained. The French furthermore at the very outset imperilled their immediate strength in the air for the sake of the future by adopting four or five machines as army types and throwing out all of other makes. More than 550 machines were thus discarded, and their services lost during the first weeks of the war. The reason for this action was the determination of the French to equip their aviation corps with standardized machines of a few types only. Thus interchangeable parts could always be kept in readiness in case of an emergency, and the aviation corps was obliged to familiarize itself with the workings of only a few machines. The objection to the system is the fact that it practically stopped all development of any machines in France except the favoured few. Moreover it threw out of the service at a stroke, or remanded for further instruction, not less than four hundred pilots who had been trained on the rejected machines. The order was received with great public dissatisfaction, and for a time threatened serious trouble in the Chamber of Deputies where criticisms of the direction of the flying service even menaced the continuance of the ministry in power.

At the outset of the war Great Britain lagged far behind the other chief belligerents in the extent of her preparations for war in the air. As has been pointed out the people of that nation had never taken the general interest in aviation which was manifested in France, and there was no persistent Count von Zeppelin to stir government and citizens into action. The situation was rather anomalous. Protected from invasion by its ring of surrounding waters, England had long concentrated its defensive efforts upon its navy. But while the danger of invasion by the air was second only to that by sea the British contemplated with indifference the feverish building of Zeppelins by Germany, and the multiplication of aircraft of every sort in all the nations of the continent. The manufacture of aircraft was left to private builders, and not until the war was well under way did the government undertake its systematic supervision. The Royal Aerial Factory, then established, became the chief manufacturer of machines for army and navy use, and acted also as the agent for the inspection and testing of machines built by private firms. Control of the Royal Flying Corps is vested in the Admiralty, the government holding that the strategy of airships was distinctly naval.

In the use of seaplanes the British were early far in the lead of other nations, as we shall see in a later chapter. And in the prompt and efficient employment of such aircraft as she possessed at the opening of the war she far outcla.s.sed Germany which in point of numbers was her superior. At that moment Great Britain possessed about five hundred machines, of which two hundred were seaplanes, and fifteen dirigibles. Despite this puny force, however, British aviators flew across the channel in such numbers to the headquarters in France that when the Expeditionary Army arrived on the scene it found ready to its hand a scouting force vastly superior to anything the Germans could put in the air. It is no exaggeration to say that the Royal Flying Corps saved Sir John French's army in his long and gallant fight against the overwhelming numbers of the foe.

Russia before the war had hidden her aeronautic activities behind the dreary curtain of miles of steppe and marsh that shut her off from the watchfulness of Western Europe. Professional aviators, indeed, had gone thither to make exhibition flights for enormous purses and had brought back word of huge airplanes in course of construction and an eager public interest in the subject of flying.

But the secrecy which all the governments so soon to be plunged in war sought to throw about their production of aircraft was especially easy for Russia in her isolation. When the storm burst her air fleet was not less than eight hundred airplanes, and at least twenty-five dirigibles.

A competent authority estimates that at the outbreak of the war the various Powers possessed a total of 4980 aircraft of all sorts. This sounds like a colossal fleet, but by 1917 it was probably multiplied more than tenfold. Of the increase of aircraft we can judge only by guesswork. The belligerents keep their output an inviolable secret.

It was known that many factories with a capacity of from thirty to fifty 'planes a week were working in the chief belligerent lands, that the United States was shipping aircraft in parts to avoid violation of neutrality laws before their entrance upon the war, and that American capital operated factories in Canada whence the completed craft could be shipped regardless of such laws. How great was the loss to be offset against this new construction is a subject on which no authoritative figures are available.

It was estimated early in the war that the life of an airplane in active service seldom exceeded three weeks. In pa.s.sing it may be mentioned that by some misapprehension on the part of the public, this estimate of the duration of a machine was thought to cover also the average life of the aviators in service. Happily this was far from true. The mortality among the machines was not altogether due to wounds sustained in combat, but largely to general wear and tear, rough usage, and constant service. The slightest sign of weakness in a machine led to its instant condemnation and destruction, for if it should develop in mid-air into a serious fault it might cost the life of the aviator and even a serious disaster to the army which he was serving. As the war went on the period of service of a machine became even briefer, for with the growing demand for faster and more quickly controllable machines everything was sacrificed to lightness and speed. The factor of safety which early in the war was six to eight was reduced to three and a half, and instances were known in all services of machines simply collapsing and going to pieces under their own weight without wound or shock.

About the extent to which the belligerent governments developed their air forces after the outbreak of war there was during the continuance of that conflict great reticence maintained by all of them. At the outset there was little employment of the flyers except on scouting reconnaissance work, or in directing artillery fire. The raids of Zeppelins upon England, of seaplanes on Kiel and Cuxhaven, of airplanes on Friedrichshaven, Essen, and Venice came later. It has been noted by military authorities that, while Germany was provided at first with the largest aviation force of all the belligerents, she either underestimated its value at the outset, or did not know how to employ it, for she blundered into and through Belgium using her traditional Uhlans for scouts, to the virtual exclusion of airmen. The effectiveness of the Belgian fight for delay is ascribed largely to the intelligent and effective use its strategists made of the few aircraft they possessed.

Wellington was wont to say that the thing he yearned for most in battle was to "see the other side of that hill."

Napoleon wrote:

Nothing is more contradictory, nothing more bewildering than the mult.i.tude of reports of spies, or of officers sent out to reconnoitre. Some locate army corps where they have seen only detachments; others see only detachments where they ought to have seen army corps.

[Ill.u.s.tration: U. & U.

_The Lafayette Escadrille--First Americans to Fly in France._ (_Lufbery on left, Thaw on right._)]

So the two great protagonists of the opening years of the nineteenth century deplored their military blindness. In the opening years of the twentieth it was healed. All that Wellington strove to see, all that the cavalry failed to find for Napoleon is to-day brought to headquarters by airmen, neatly set forth in maps, supported by photographs of the enemy's positions taken from the sky.

Before describing the exploits of the airmen in actual campaign let us consider some account of how they were trained for their arduous and novel duties.

To the non-professional an amazing thing about the employment of aircraft in war has been the rapidity with which pilots are trained.

The average layman would think that to learn the art of manoeuvring an airplane with such swiftness as to evade the attacks of an enemy, and to detect precisely the proper moment and method of attacking him in turn, would require long and arduous practice in the air. But as we have seen in earlier chapters, inventors like the Wrights, Bleriot, and Farman learned to fly with but a few hours spent in the air, with flights lasting less than ten minutes each. So too the army aviators spent but little time aloft, though their course of instruction covered in all a period of about four months.

Some account of the method of instruction as reported by several out of the hundred or more American boys who went to fly for France may be interesting.

As a rule the aviators were from twenty to twenty-five years of age.

"Below twenty boys are too rash; above twenty-five they are too prudent," said a sententious French aviator. A slight knowledge of motors such as would be obtained from familiarity with automobiles was a marked advantage at the start, for the first task of the novice was to make himself familiar with every type of airplane engine. The army pilot in all the armies was the aristocrat of the service. Mechanics kept his motor in shape, and helpers housed, cleaned, and brought forth his machine for action. But while all but the actual piloting and fighting was spared him, there was always the possibility of his making an untimely landing back of the enemy's lines with an engine that would not work. To prepare for such an emergency he was taught all the intricacies of motor construction, so that he might speedily correct any minor fault.

In our army, and indeed in all others, applicants for appointment to the aviation corps were subjected to scientific tests of their nerves, and their mental and physical alertness. How they would react to the sudden explosion of a sh.e.l.l near their ears, how long it took the candidate to respond to a sudden call for action, how swiftly he reacted to a sensation of touch were all tested and measured by delicate electric apparatus. A standard was fixed, failing to attain which, the applicant was rejected. The practical effect might be to determine how long after suddenly discovering a masked machine gun a given candidate would take before taking the action necessary to avoid its fire. Or how quickly would he pull the lever necessary to guard against a sudden gust of wind. To the layman it would appear that problems of this sort could only be solved in the presence of the actual attack, but science, which enables artillerists to destroy a little village beyond the hills which they never see, was able to devise instruments to answer these questions in the quiet of the laboratory.

One of the best known flying schools of the French army was at Pau, where on broad level plains were, in 1917, four separate camps for aviators, each with its group of hangars for the machines, its repair shops, and with a tall wireless tower upstanding in the midst for the daily war news from Paris. On these plains the Wright Brothers had made some of their earliest French flights. A little red barn which they had made their workshop was still standing there when war suddenly turned the spot into a flying school often with as many as five thousand pupils in attendance. "To-day that little red barn," writes Carroll Dana Winslow, one of the Americans who went to fly for France, "stands as a monument to American stupidity, for when we allowed the Wrights to go abroad to perfect their ideas instead of aiding them to carry on their work at home we lost a golden opportunity. Now the United States which gave to the world the first practical airplane is the least advanced in this all-important science."

Arrived at the school the tyro studies the fundamentals of flying in the cla.s.sroom and on the field for two months before he is allowed to go up--to receive as they express it, his _bapteme de l'air_. He picks motors to pieces, and puts them together, he learns the principles of airplane construction, and can discourse on such topics as the angle of attack of the cellule, the incidence of the wings, and the carrying power of the tail-plane. More than any other science aviation has a vocabulary of its own, and a peculiarly cosmopolitan one drawn from all tongues, but with the French predominating. America gave the airplane to France, but France has given the science its terminology.

The maps of the battlefields of this war are the marvels of military science. Made from the air they show every road and watercourse, every ditch and gully, every patch of woodland, every farmhouse, church, or stonewall. Much of the early work of the aviator is in learning to make such maps, both by sketches and by the employment of the camera. It is no easy task. From an airplane one thousand feet up the earth seems to be all a dead level. Slight hills, gentle elevations, offer no contrast to the general plain. A road is not easy to tell from a trench. All these things the aviator must first learn to see with accuracy, and then to depict on his map with precision. He must learn furthermore to read the maps of his fellows--a task presupposing some knowledge of how they had been made. He must learn to fly by a map, to recognize objects by the technical signs upon it, to estimate his drift before the wind because of which the machine moves sidewise _en crabe_--or like a crab as the French phrase it.

His first flight the novice makes in a machine especially fitted for instruction. The levers are fitted with double handles so that both learner and tutor may hold them at once. If the greenhorn pushes when he should pull the veteran's grip is hard on the handle to correct the error before it can cost two lives--for in the air there is little time to experiment. Either set of controls will steer the machine. The pupil grasps his levers, and puts his feet on the pedals. At first the instructor will do the steering, the pupil following with hands and feet as the motions made by the instructor are communicated to him by the moving levers. For a time the two work together. Then as the instructor senses that the student himself is doing the right thing he gradually lessens his own activity, until after a few days' practice the student finds that he is flying with a pa.s.senger and directing the machine himself. In France, at any rate, they teach in brief lessons. Each flight for instruction is limited to about five minutes. At first the student operates in a "penguin"--a machine which will run swiftly along the ground but cannot rise. It is no easy trick at first, to control the "penguin" and keep its course direct. Then he will try the "jumps"

in a machine that leaps into the air and descends automatically after a twenty to forty yards' flight. As Darius Green expressed it so long ago, the trouble about flying comes when you want to alight.

That holds as true to-day with the most perfect airplanes, as in boyhood days when one jumped from the barn in perfect confidence that the family umbrella would serve as a parachute. To alight with an airplane the pilot--supposing his descent to be voluntary and not compelled by accident or otherwise--surveys the country about him for a level field, big and clear enough for the machine to run off its momentum in a run of perhaps two hundred yards on its wheels. Then he gets up a good rate of speed, points the nose of the 'plane down at a sharp angle to the ground, cuts off the engine, and glides. The angle of the fall must be great enough for the force of gravity to keep up the speed. There is a minimum speed at which an airplane will remain subject to control. Loss of speed--"_perte de vitesse_," as the French call it--is the aviator's most common peril in landing. If it occurs after his engine is cut off and he has not the time to start it again, the machine tilts and slides down sideways. If it occurs higher up a _vrille_ is the probable result.

In this the plane plunges toward the ground spinning round and round with the corner of one wing as a pivot. In either case a serious accident is almost inevitable.

In fact the land is almost as dangerous to the navigator of the air as it is to him of the sea. To make good landings is an art only perfected by constant practice. To shut off the engine at precisely the right moment, to choose an angle of descent that will secure the greatest speed and at the same moment bring you to your landing place, to change at the most favourable time from this angle to one that will bring you to the ground at the most gentle of obtuse angles, and to let your machine, weighing perhaps a ton, drop as lightly as a bird and run along the earth for several hundred feet before coming to a full stop, are all features of making a landing which the aviator has to master.

In full air there are but few perils to encounter. All airmen unite in declaring that even to the novice in an airplane there is none of that sense of dizziness or vertigo which so many people experience in looking down from high places. The flyer has no sense of motion.

A speed of forty miles an hour and of one hundred miles are the same to him. As he looks down the earth seems to be slipping away from him, and moving by, tailwards, like an old-fashioned panorama being unwound.

Everything about the control of an airplane has to be learned mechanically. Once learned the aviator applies his knowledge intuitively. He "senses" the position and progress of the craft by the feel of the controls, as the man at the yacht's tiller tells mysteriously how she is responding to the breeze by "the feel." Even before the 'plane responds to some sudden gust of wind, or drops into a hole in the air, the trained aviator will foresee precisely what is about to happen. He reads it in some little thrill of his lever, a quiver in the frame, as the trained boxer reads in his antagonist's eyes the sort of blow that is coming. This instinctive control of his machine is absolutely essential for the fighting pilot who must keep his eyes on the movements of his enemy, watch out for possible aircraft guns below, and all the time be striving to get an advantageous position whence he can turn his machine gun loose. A row of gauges, dials, a compa.s.s, and a map on the frame of the car in which he sits will engage his attention in any moments of leisure. It is needless to remark that the successful pilot must have a quick eye and steady nerves.

Nerve and rapidity of thought save the aviator in many a ticklish position. It is perhaps a tribute to the growing perfection of the airplanes that in certain moments of peril the machine is best left wholly to itself. Its stability is such that if freed from control it will often right itself and glide safely to earth. This not infrequently occurs in the moment of the dreaded _perte de vitesse_, to which reference has been made. In his book, _With the French Flying Corps_, Mr. Carroll Dana Winslow, a daring American aviator, tells of two such experiences, the one under his observation, the other happening to himself:

The modern airplane is naturally so stable [he says] that if not interfered with it will always attempt to right itself before the dreaded _vrille_ occurs, and fall _en feuille morte_. Like a leaf dropping in an autumn breeze is what this means, and no other words explain the meaning better.

A curious instance of this happened one day as I was watching the flights and waiting for my turn. I was particularly interested in a machine that had just risen from the "Grande Piste." It was acting very peculiarly. Suddenly its motor was heard to stop.

Instead of diving it commenced to wabble, indicating a _perte de vitesse_. It slipped off on the wing and then dove. I watched it intently, expecting it to turn into the dreaded spiral. Instead it began to climb. Then it went off on the wing, righted itself, again slipped off on the wing, volplaned, and went off once more.

This extraordinary performance was repeated several times, while each time the machine approached nearer and nearer to the ground.

I thought that the pilot would surely be killed. Luck was with him, however, for his slip ceased just as he made contact with the ground and he settled in a neighbouring field. It was a very b.u.mpy landing but the airplane was undamaged.

The officers rushed to the spot to find out what was the matter.

They found the pilot unconscious, but otherwise unhurt. Later in the hospital he explained that the alt.i.tude had affected his heart and that he had fainted. As he felt himself going he remembered his instructions and relinquished the controls, at the same time stopping his motor. His presence of mind and his luck had saved his life--his luck I say, for had the machine not righted itself at the moment of touching the ground it would have been inevitably wrecked.

The spectacle, though terrifying, proved valuable as an education to young Winslow who a few days later was ordered to a test of ascension of two thousand feet. This is his story:

I had a narrow escape. I had received orders to make a flight during a snow-storm. I rose to the prescribed height and then prepared to make my descent. A whirling squall caught me in the act of making a spiral. I felt the tail of my machine go down and the nose point up. I had a cla.s.sical _perte de vitesse_. I looked out and saw that I was less than eight hundred feet above the ground and approaching it at an alarming rate of speed. I had already shut off the motor for the spiral, and turning it on, I knew, would not help me in the least. Suddenly I remembered the pilot who fainted. I let go of everything, and with a sickening feeling I looked down at the up-rushing ground. At that instant I felt the machine give a lurch and right itself. I grabbed the controls, turned on the motor, and resumed my line of flight only two hundred feet in the air. All this happened in a few seconds, but my helplessness seemed to have lasted for hours. I had had a very close call--not as close as the man who fainted, but sufficiently so for me.

[Ill.u.s.tration: _Distinguishing Marks of American Planes._]

We have said that the process of training a flyer is remarkably expeditious. So far as the fundamentals of his profession are concerned it is. But his education in fact never ends. In the mere matter of reconnaissance, for example, experience is everything. One might imagine that ten thousand men marching on a road would look alike in numbers whatever the nationality. Not so. To the untrained eye five thousand or six thousand French troops will look as numerous as ten thousand British or Germans. Why? Because the French march in much more extended order. Into their democratic military methods the precision and mechanical exact.i.tude of German drill do not enter. With the same number of troops they will extend further along the road by at least a third than would a detachment of either of the other armies.

[Ill.u.s.tration: _What an Aviator must Watch._

1 _Watch_ 2 _Altimeter-registering height_ 3 _Compa.s.s_ 4 _Pressure gauges for two gasoline tanks_ 5 _Dial registering engine revolutions_ 6 _Inclinometer, registering level fore and aft_ 7 _Oil pulsator_ 8 _Control stick, with thumb switch_ 9 _Switches, two magnetos_ 10 _Air speed indicator_ 11 _Gasolene supply pipe_]

And again. Great skill has been developed in the course of the war in the art of concealing positions and particularly in disguising cannon. The art has given a new word to the world--_camouflage_.

Correspondents have repeatedly told of their amazement in suddenly coming across a battery of 75's, or a great siege gun so cunningly hidden in the edge of a thicket they would be almost upon it before detecting it. From an airplane 2500 feet or more in the air it requires sharp eyes to penetrate artillery disguises. A French poilu in a little book of reminiscences tells with glee how a German observation aviator deceived his batteries. A considerable body of French troops being halted in an open field, out of sight of the enemy batteries, found the glare of the sun oppressive, and having some time to wait threw down their equipment and betook themselves to the cool shadows of a neighbouring wood. Along came an enemy aviator. From his lofty height the haversacks, blanket-rolls, and other pieces of dark equipment lying upon the gra.s.s looked like a body of troops resting. After sailing over and around the field twice as though to make a.s.surance doubly sure he sailed swiftly away. In a very few minutes sh.e.l.ls from a concealed battery began dropping into that field at the rate of several a minute. Every foot of it was torn up, and the French soldiers from their retreat in the woods saw their equipment being blown to pieces in every direction.

The spectacle was harrowing, but the reflection that the aviator undoubtedly thought that he had turned his guns on a field full of men was cheering to them in their safety.

An art which the fighting aviator must master early in his career is that of high diving. Many of us have seen a hawk, soaring high in air, suddenly fold his pinions and drop like a plummet full on the back of some luckless pigeon flapping along ungainly scores of feet below, or a fishhawk drop like a meteor from the sky with a resounding splash upon the bosom of some placid stream and rise again carrying a flapping fish to his eyrie in the distant pines.

The hunting methods of the hawk are the fighting methods of the airman. But his dives exceed in height and daring anything known to the feathered warriors of the air.

Boelke, most famous of all the German airmen--or for that matter of all aerial fighters of his day--who in 1917 held the record for the number of enemy flyers brought down, was famed for his savage dives.

He would fly at a great height, fifteen thousand or more feet, thus a.s.suring himself that there was no enemy above him. When he sighted his prey he would make an absolutely vertical nose dive, dropping at the rate of 150 miles an hour or more and spattering shots from his machine gun as he fell. Six hundred shots a minute and the sight of this charging demon were enough to test the nerve of any threatened aviator. In some fashion Boelke was enabled to give a slight spiral form to his dive so that his victim was enveloped in a ring of bullets that blocked his retreat whichever way he might turn for safety.

Personality in fighting counted much for success. Boelke's method, its audacity and fierceness, placed him first in the list of airmen with killing records. Captain Immelman, also a German, who rolled up a score of thirty enemies put out of action before he himself was slain, followed entirely different tactics. His battle manoeuvre savoured much of the circus, including as it did complete loop-the-loop. For instead of approaching his adversary from the side, or as would be said in the sea navy, on the beam, he followed squarely behind him. His study was to get the nose of his machine almost on the tail of the aircraft he was pursuing. This gave him, to begin with, what used to be called in the navy a raking position, for his shots would rake the whole body of the enemy airplane from tail to nose with a fair chance of hitting either the fuel tank, the engine, or the pilot. Failing to secure the position he most coveted, this daring German would surrender it with apparent unconcern to the enemy who usually fell into the trap. For just as the foeman's machine came up to the tail of Immelman's craft the latter would suddenly turn his nose straight to earth, drop like a stone, execute a backward loop, and come up behind his surprised adversary who thus found the tables suddenly turned.

These two German aviators long held the record for execution done in single combat. Boelke was killed before the air duel vanished to be replaced by the battle of scores of planes high in air. Immelman survived longer, but with the incoming of the pitched battle his personal prowess counted for less and his fame waned.

In July, 1917, arrangements were complete in the United States for the immediate training in the fundamentals of aviation of ten thousand young Americans. The expectation was that long before the end of the year facilities would be provided for the training of many more. Both France and Great Britain sent over squads of their best aviators, some of them so incapacitated from wounds as to be disqualified for further fighting, but still vigorous enough for the work of an instructor. The aerial service took hold upon the imagination and the patriotism of young America as did no other. The flock of volunteers was far beyond the capacity of the government to care for, and many drifted over into private aviation schools which were established in great numbers. The need for the young students was admittedly great. More and more the impression had grown in both Great Britain and France that the airplane was to be the final arbiter in the war. It was hailed at once as the most dangerous enemy of the submarine and the most efficient ally of troops in the field. No number seemed too great for the needs of the entente allies, and their eagerness to increase their flying force was strengthened by the knowledge of the fact that Germany was building feverishly in order that its fleet in the air might not be eclipsed.