How pilots fought the wind—Military demands for an “airworthy” machine—Value of the air-scout—Dangers in wind-flying—The “side-slip”—Aeroplanes that are automatically stable.

It has been shown how aeroplanes were built and made to fly, and not machines of one particular make, but biplanes and monoplanes of various types of construction; also how, granted he had a reliable motor, a man might fly for hours without alighting. These were the lessons of 1909; these, and the fact that flying was proved an art that could be learned by any man who was active and had sound nerves. After Wilbur Wright had taught his first pupils, and Bleriot and Farman had established training schools, men in rapidly increasing numbers came to learn to fly; so that, quite early in 1910, it was possible to list the names of more than 200 pilots.

Progress was now revealed in two directions: firstly, encouraged by engine reliability, airmen made cross-country flights; and secondly, becoming more used to being in the air, and gaining confidence in the handling of their machines, they began to fly in gusty winds. This was shown by the fact that, fearing any breeze at first that was higher than 10 or 15 miles an hour, pilots soon combated winds of 20 and 25 miles an hour.

Flights of 100 miles were made across country; one historic example, of course, was M. Paulhan’s 183-mile journey from London to Manchester, made in 242 minutes and with but one halt, by which he won The Daily Mail £10,000 prize, and in which—meeting him in keen but friendly rivalry as the representative of England—he had the joint author of this book, Mr. Claude Grahame-White.

The confidence of pilots in the reliability of their machines was demonstrated conclusively by the Comte de Lambert. Rising from the aerodrome at Juvisy, near Paris, he flew over the city and circled the Eiffel Tower, returning afterwards without accident to his starting-point.

Several more airmen had, by this time, succeeded in crossing the Channel, and a notable feat was that of the Hon. C. S. Rolls, who flew from Dover till he reached the French coast near Calais; then, circling without a descent, he returned to his starting-point—a flight over-sea that lasted an hour and a half. In high flying, too, the confidence of airmen was displayed. At Rheims in 1909, it may be remembered, Latham rose 500 feet, and this was considered remarkable. But the record, during 1910, was beaten and beaten again, until it stood at nearly 10,000 feet. In speed also, using monoplanes with 50-h.p. motors, pilots made records day by day; and an English airman, Mr. Radley, flying over a measured course in August 1910, in a Bleriot monoplane, attained a speed of more than 70 miles an hour.

In the duration of flight, which proved the reliability of engines, great strides also were made. From Farman’s 4-hour record at the end of 1909, the figure was carried till it stood at 6 hours 1 minute 35 seconds. This flight was made by Tabuteau, an airman flying a Maurice Farman biplane. Maurice was a brother of the famous Henri, and he built a biplane which, while resembling the Henri Farman in general aspect, was different in detail. In the first machines he built,—and it is one of these the sketch (Fig. 52) shows,—Maurice Farman used, in addition to ailerons, two side curtains or panels, as the Voisins had done; but these he afterwards abandoned, retaining ailerons alone. A feature of this machine was the way in which the landing skids were continued upward, so as to form the supports for the elevating-plane. The Maurice Farman developed into a stable and remarkably successful craft, greatly used for cross-country flying and by military pilots.

The chief triumph of 1910 was the fight airmen waged against the wind. This was their enemy—an enemy which sought to chain them to the ground, and prevent their craft from becoming of practical use. One point, indeed, became clear: it was of little value to fly high or for long distances, if one could only do so in favourable weather. The aeroplane, if it was to play a practical part in the affairs of the world, must ascend in high winds as well as in calms. This being recognised, there was strenuous effort to produce an “all-weather” machine. Particularly was wind-flying of value in the military use of aeroplanes; and it is here that we reach a vital aspect of aviation. Immediately craft could fly across country, and ascend high enough for a view of the land to be obtained from them, it was seen they would have a great value as scouts in time of war.

There has, from the earliest days of battle, been a need for scouting—a need for news as to what the enemy is doing. Picture two armies about to engage. They approach each other cautiously, troops spread out and dotted here and there; while in front of each force is thrown a screen of outposts. These form a protective fence, through which the scouts of the enemy find it difficult to penetrate. What the scouts seek to discover is how many men there are in the army moving forward, how many guns, and how these men and guns are being massed and drawn up for the battle that impends. But the outposts head them off and shoot them down; and as both armies have outposts, and as both sets of scouts find the same difficulty in obtaining news, the two forces may grope and blunder into battle without knowing such facts as to numbers and positions as might spell the difference between victory and defeat. Of course, the scouts do their best, some on foot, some horsed; but it was Napoleon who wrote:

“Nothing is more contradictory, nothing more bewildering, than the multitude 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.”

But now came the aeroplane, and strategists seized the opportunities it offered. Outposts could do nothing against such a scout as this; instead of seeking to dodge them through a wood, or round a hill, it could pass thousands of feet above their heads; and the earth below, as viewed by the spy sitting in his machine, would be spread out like a panorama; he would see the troops of the enemy in motion, and note their strength and the positions to which they moved. No wonder the War Departments of Europe were ready to buy aeroplanes. Buy them they did, indeed, in growing numbers; but the drawback of the early machines was that they were fair-weather craft; they would not fly in winds. Imagine that a battle impends, and that the Commander-in-Chief of one army seeks news as to the movements of some division of his enemy; so he orders the air-scouts to ascend. But the wind may be blowing hard; and if it is, and the aeroplanes are only fair-weather machines, they will have to remain on the ground till the wind drops, and perhaps miss their greatest chance during a whole campaign.

But it was astonishing how, feeling greater confidence in the handling of their machines, airmen began to join issue with this enemy the wind. They were helped, too, by a growing efficiency in the construction of their craft. Machines were built more strongly, engines were more staunchly made; in all details that spelt reliability, were aircraft improved. But the wind, none the less, took its toll. It was not combated without loss of life; and we find that, before the end of 1910, nearly thirty men had been killed while flying. In many cases, struck by a heavy gust, a machine collapsed in flight; in others, beaten over by the force of the wind, but with his craft intact, the pilot had fallen to earth, powerless to regain the control of his machine.

In wind-flying there were these two distinct dangers: a man might be dashed to earth by a gust when rising or descending; or he might be struck by a rush of wind when at a considerable height, and find his craft driven over until it began to slip sideways instead of flying forward. In “side-slips,” as they are called, there lies a grave risk. What happens is this. A man flying in a wind may, by vigorous use of his ailerons, recover the balance of his machine time after time; but as the wind rises, he may be struck ultimately by a gust that tilts his planes to an abnormal angle, despite his efforts to check them. The machine will then heel till it stands almost vertical—till it reaches such an angle, in fact, that it ceases to move forward and begins to slip sideways—skidding away, beyond the pilot’s control, like a motor on a greasy road. How an abnormal gust may cause a side-slip is illustrated by Fig. 53.

In such a predicament, two things only can save the airman; one his height above the ground, the other his nerve and presence of mind. If he is flying low when his machine side-slips, nothing can avert disaster. Falling at first sideways in a helpless lurch, then diving violently, the craft will strike ground with shattering force—completely beyond its pilot’s control. But if the airman is flying high, and granted he is a man of experience, he may escape even the worst of side-slips, and how he does so is as follows: as his machine slips he puts forward his elevating-lever as far as it will go, throws over his rudder to help the action of the elevator, and sets his motor at its fullest power—these actions seeming, in themselves, merely to aggravate the peril by causing the craft to fall more quickly. But the pilot knows what he is doing; he knows that, so long as his craft slips sideways, it is impossible for his controlling planes to act, seeing that they are effective only when the machine moves forward through the air. What he seeks to do, therefore, is to convert the side-slip into a forward dive. If he can do this—if he has space for the manoeuvre before the machine strikes ground—he knows he can avert disaster.

In throwing over his elevating-lever, and accelerating his motor, his aim would be to make his machine fall forward more rapidly than it is slipping sideways; and, as a rule, under the combined thrust of the motor, and the extreme angles of elevating-plane and rudder, the craft will—after a sickening slip, perhaps of several hundred feet—begin to lose its sideway motion and plunge straight downward. His elevating plane will then become operative, tending to check this dive and bring up the bow of the machine; and at the same time, feeling he has regained control, the pilot will throttle down his motor so as to reduce the speed of his machine. In this way, responding to the action of its elevator, the craft will pause in its downward rush, and sweep forward again upon an even keel. But the actions of the pilot, in such a quandary, need to be accurately and boldly made; and unless his craft flies high, no skill can save it. If he has not a thousand feet or more below him, he will be dashed to death before his manoeuvre has time to take effect.

The moral, therefore, lay in flying high, and it was one that pilots respected. Instead of passing across country at a few hundred feet, they began soon to ascend 3000 feet and more; and at such altitudes, apart from the greater safety in case of side-slip, an airman found usually a steadier and less gusty wind, and was in a better position to choose some landing-point should his motor fail suddenly.

When starting across country, particularly in the early days, a pilot had to consider very seriously the question of the failing of his motor. So long as he had an aerodrome below him, its smooth surface providing an alighting spot, he felt no great concern. But in flying across country, should his motor stop, he might find himself above a forest, or a sheet of water, or such rough and broken land that his machine would be damaged were he to alight upon it. But here again, as in the case of side-slip, altitude would tend to safety.

In the stoppage of its motor, when a craft is in flight, several factors need consideration; but one should clearly be understood: even if his engine does fail while he is passing through the air, a pilot is not helpless, nor does his machine fall to the ground. As he flies, of course, it is the thrust of his motor, acting through the medium of the propeller, that keeps his craft moving forward; and so long as this thrust is there, forcing his planes against the air and causing them to lift their load, the machine will fly ahead. But what happens should the engine fail, and the machine cease to be propelled? The first effect is that the craft begins to lose its speed, and as it does this its planes are less operative. Unless he can restore his forward speed, therefore, and so maintain the lift of his planes, the pilot is in peril. Were he merely to sit still after his engine failed, and do nothing to save himself, he would be in a position of the greatest risk. What would happen would be that his craft, having no power thrusting it against the air, would come gradually to a standstill; then, its planes exercising no further lift, it would lose equilibrium and fall.

But there is another force the airman can use, even when his motor fails entirely; and this is the downward pull of gravity, which acts unceasingly upon his machine. He must, at all costs, restore the speed of his craft; not only that its main-wings may bear their weight, but that its controlling-planes may continue operative, and enable him to steer towards a landing-point. What he does, therefore, when he hears his motor stop, is to tilt his elevating lever and send his machine upon a dive. Thus, even with no motor to propel him, he can still fly. It is gravity now that moves his machine, and so long as he keeps his lever forward, and sends his craft downward upon a gradually sloping path, he has perfect control and need not fear a fall. Air is still being forced under his planes; therefore, they bear their load; and, seeing that the machine is moving forward, its rudder and other controlling planes are able to do their work. The airman is, in fact, as much in command of his machine as he was before its motor stopped—save for one vital difference. While his motor ran he could fly where he pleased; but now he is obliged to glide downward. He is, indeed, in the same position as was Lilienthal, or any of the men who soared from hilltops. But, being say 1000 feet or more high when his engine stops, he has the advantage of a long glide before he reaches ground; and this gives him a chance, surveying the land below him, to pick a smooth landing-point that may lie in his path. If well-designed, an aeroplane will glide a long way after its motor has failed, as is indicated by Fig. 54. In this case, representing an actual test with a military machine, the motor has stopped at an altitude of between 1200 and 1400 feet, and the craft glides, before touching ground, a distance of nearly 9000 feet.

This gliding without motive power is a safeguard to the airman when he flies across country. Should he attain a sufficient altitude, he has little to fear, even if his engine does fail. As he glides down, he can steer from side to side, or make a half circle and land upon a spot that lies behind him. An aeroplane with a gliding path of 1 foot in 10, and at a height of a mile when its engine stopped, would glide ten miles before alighting. Taking an extreme case, one might imagine an airman flying over a city. Suddenly, while above a network of streets and houses, his engine stops. But even in such a quandary as this, granted he has the wisdom to be several thousand feet high, he need not fear disaster. Glancing keenly below him, he sights some park or open space like an oasis among the close-packed buildings, and glides swiftly and accurately towards it, landing without difficulty or injury to his machine.

The making of a gliding descent, or vol-planÉ, is an art all airmen learn; and the vital thing to remember in connection with it is, that the machine must always move swiftly forward. Sometimes, checking his glide too soon, a pupil at the schools will make what is called a “pancake” landing: that is to say, misjudging his height above the ground, he stops the glide of his craft, by a movement of the elevating plane, when he is still 15 or 20 feet in the air. The result is that the machine comes to a standstill, then drops flat upon its wheels; and in doing so it may break its chassis supports, and give the pupil a shaking. The art, in a gliding descent, is to lessen the steepness of the dive, by throwing up the elevating plane only a second or so before the landing-wheels make their contact with the ground. Then, its downward speed checked—in the same way that a bird checks itself, just before its feet touch earth—the wheels of the craft will meet the surface smoothly, and there will be no shock or rebound.

A. Upper main plane; B.B. Lower main plane; C.C. Hinged flaps which act as air brakes.