Learning to Fly: A Practical Manual for Beginners

THE CONTROLLING OF LATEST-TYPE CRAFT

People are puzzled, often, when they try to explain to themselves how it is that an aeroplane, which is so much heavier than air, manages to leave the ground and to soar in flight. When balloons or airships ascend, it is realised of course that the gas, imprisoned within their envelopes, draws them upward. But the aeroplane—weighing with pilot, passenger, and fuel perhaps several thousand pounds—rises without the aid of a gas-bag and with nothing to sustain it but narrow planes; and these do not beat, like the wings of a bird, but are fixed rigidly on either side of its body. How is the weight of machine and man borne through this element we cannot see, and which appears intangible?

The secret is speed—the sheer pace at which an aeroplane passes through the air. As a craft stands on the ground, its planes are inoperative. Power lies dormant in the air, but only when it is in motion, or when some object or apparatus is propelled through it at high speed. Have you stood on a height, in a gale, and felt an air wave strike powerfully against your body? The blow is invisible; but you yield a step, gasping; and, had you wings at such a moment, you would not doubt the power of the wind to sweep you upward. This is the force the aeroplane utilises.

If, on a calm day, you accelerate your motor-car to 60 miles an hour, the air sweeps past you in a powerful stream; just as it would if you were standing still, and there was a gale of wind. Instead of the wind possessing the speed, in this instance, it is you who provide it. The motor of an aeroplane, driving the propeller of the machine, turns this at 1000 or more revolutions a minute, and causes its curved blades to screw forward through the air as they turn, like those of a ship's propeller through water—or a gimlet into wood. The propeller, as it bores its way into the air, draws or pushes the aeroplane across the ground; and the speed grows rapidly until the air, sweeping with an increasing pressure beneath the planes, becomes sufficient to bear the craft in flight.

But the wing of an aeroplane would not sustain its load unless designed specially to act upon the air. A man, if he is unlucky enough to fall from a tall building, passes through the air at a high speed. His body obtains no support from the air; so he crashes to the ground. This is because his body is heavy, and presents only a small surface to the air. To secure a lifting influence from the air, it must be struck swiftly with a large, light surface.

Men go to Nature when building wings for aeroplanes, and imitate the birds. The wing of a bird arches upward from front to back, most of the curve occurring near the forward edge; and this shape, when applied to an aeroplane wing, is known as its camber. With an aeroplane wing, if its curve is adjusted precisely, the air not only thrusts up from below as a machine passes through it, but has a lifting influence also from above; an effect that is secured by the downward slope of the plane towards its rear edge. The air, sweeping above the raised front section of the plane, is deflected upward, and with such force that it cannot descend again immediately and follow the downward curve of the surface. So, between this swiftly-moving air stream, and the slope to the rear of the plane, a partial vacuum is formed, and this sucks powerfully upward. With a single wing, therefore, it is possible to gain a double lifting influence—one above and one below.

The building of aeroplanes, once their wing lift is known, becomes a matter of precision. According to the speed at which they fly, and the size and curve of their planes, machines will sustain varying loads. In some machines, as a general illustration—craft which fly fast—the planes may bear a load equal to 10 lbs. per square foot. In others the loading may be less than 3 lbs. per square foot.

Apart from raising a craft into the air, by the lifting power of its wings, there is the problem of controlling it when in flight. The air is treacherous, quickly moving. Gusts of abnormal strength, sweeping up as they do invisibly, may threaten to overturn a machine and dash it to earth. Eddies are formed between layers of warm and cold air. There are, as a craft flies, constant increases or lessenings of pressure in the air-stream that is sweeping under and over its wings; and all these fluctuations influence its equilibrium. Unless, therefore, a machine is automatically stable—and with craft of this type we shall deal later—the pilot must be ready, by a movement of the surfaces which govern the flight of the machine, to counteract quickly, with a suitable action of his levers, the overturning influence that may be exercised by a gust of wind. Here lies the art of flying. A man is given a machine which, by the action of its motor and propeller, will raise itself into the air; and it is his task, when the craft is once aloft, to manipulate it accurately and without accident, and to bring it to earth safely after he has made a flight.

In the description of controlling movements which follows we shall, for the sake of convenience, and for the sake also of brevity, deal only with the type of "pusher" biplane to which reference has been made already, and on which large numbers of pupils have been, and are being, trained to fly. This casts no aspersion whatever on tractor machines or on monoplanes. On either, if he has an inclination, a pupil can undergo his instruction, and do so usually with success. But explanation is rendered more easy, and there is less likelihood of a dispersal of interest, if one machine is selected for illustration; and our reasons for the choice of a "pusher" biplane, regarded from the point of view of tuition, have been explained already.

First, therefore, one may deal with raising the craft into the air, and causing it to descend. In the photograph of the school machine shown, facing this page it will be seen that the control surfaces are indicated by lettering. In front of the biplane, on outriggers, is the plane "A." This surface (aided in its action by a rear plane) governs the rise or descent of the machine. When the motor is started, and the propeller drives the biplane across the ground on its chassis B, the machine would, if this lifting plane was held in a negative position, continue to move forward on the earth and would make no attempt to rise. In order to leave the ground, when the speed of the machine is sufficient for its main-planes (C.C.) to become operative, and bear its weight through the air, the pilot draws back slightly towards him a lever, which is placed just to the right of his driving-seat and is held with the right hand. A photograph which shows this lever, and the other controls, appears, facing page 36 the lever to which we are referring being indicated by the figure 1. The effect on the aircraft when the pilot draws back this lever—the motion being slight and made gently—is to tilt up the elevating plane A, and this in its turn, owing to the pressure of air upon it, raises the front of the machine. The result of this alteration in the angle of the craft is that it presents its main-planes at a steeper angle to the air. Their lifting influence is increased, with the result that—at an angle governed by the pilot with his movement of the elevating plane—they bear the machine from the ground into the air.

A pilot must be able to do more than cause his aeroplane to ascend and to alight: he must have means to check the lateral movements which, under the influence of wind gusts, may develop while the biplane is in flight. At the rear extremities of the main-planes as illustrated in the photograph facing page 34—and marked D.D.—are flaps, or ailerons, which are hinged so that they may be either raised or lowered. These ailerons are operated, through the medium of wires, by the same hand-lever which governs the movement of the elevator. This lever is mounted on a universal joint, and can be moved from side to side as well as to and fro. Should the biplane tilt, while flying, say towards the left, the pilot moves his hand-lever sideways towards the right. This is a natural movement, the instinct being to move the lever away from the direction in which the machine is heeling. This movement of the lever has the effect of drawing down the ailerons on the left-hand side of the machine; on the side, that is to say, which is tilted down; and the depression of these auxiliary surfaces, increasing suddenly as they do the lifting influence of the main-planes to which they are attached, tend to thrust up the down-tilted wings, and so restore the equilibrium of the machine.

In the operation of his ailerons, combined with the use of his elevator, a pilot is given means to balance his craft while in flight. One should not gain the impression that an aeroplane is threatening ceaselessly to heel this way and that. This is not so. The machine has a large measure of stability, apart from any manipulation of its controls, and needs balancing only when some disturbance of the atmosphere affects its equilibrium. Under favourable conditions, such as a pupil will experience in his first flights, nothing more is necessary with the hand-lever than a very slight but fairly constant action; a similar motion, in a way, as is made by the driver of a motor-car when he maintains, by his "feel" on the wheel, his sense of control over the machine. In the controlling actions of an aeroplane—and this is a fact which tends sometimes to the confusion of the novice—nothing more is required, normally, than the most delicate of movements. The difference say between ascending, and skimming along the ground, is represented by a movement of the hand-lever of only a few inches. Delicate, sure, quick, and firm; such is the touch needed with an aeroplane.

With the one hand-lever, as we have shown, it is possible for a pilot to control the rise and descent, and also the lateral movements of his machine; and there remains only the steering to be effected—the movement from side to side, from right to left, or vice-versa. At the rear of the biplane, as shown, facing page 34 will be seen two vertical planes, E.E. These, being hinged, will swing from side to side; and they exercise a sufficient influence, when working in the strong current of air that blows upon them when a machine is in flight, to steer it accurately in any direction. The pilot, to operate this rudder, rests his feet on a conveniently-placed bar, which is mounted on a central swivel, and allows the bar to be swung by a pressure of either foot. When the pilot needs to make a turn say to the left, as he is flying, he presses his left foot forward. This swings the bar in same direction; and, by a simple connection of wires running to the tail of the machine, the rudders are made to swing over to the left also, and the machine turns in response to them. A similar movement to the right produces a right-hand turn. This foot rudder bar, being numbered 2, is shown in the picture facing page 36.

CHAPTER V

THE STAGES OF TUITION

Flying schools—those which really can be described as such—have been in operation now for seven years; and during this time, with thousands of pupils going through their period of tuition, many very valuable lessons have naturally been learned. To-day, at a well-managed school, each stage in a pupil's instruction, mapped out as a result of experience, is arranged methodically and with care; the idea being that the novice should pass from one stage to another by a smoothly-graduated scale, facilitating his progress and reducing elements of risk.

It is in the early morning, and again in the evening, that the flying schools are most busy as a rule. At such times—morning and evening—the wind blows with least violence; and it is very necessary that a pupil, when he is handling craft for the first time, should have weather conditions which are favourable. Summer and winter, as soon as it is light, and granted conditions appear suitable, mechanics wheel the aeroplanes from the sheds, and the instructors begin their work. Should there be any doubt as to the weather, or as to the existence, say, of difficult air currents, an instructor will fly first, circling above the aerodrome at various heights, and satisfying himself, by the behaviour of his machine, whether it will be safe for the novices to ascend. If he pronounces "all well," school work begins in earnest, and continues—provided the weather remains favourable—until all the pupils have had a spell of instruction. Towards the middle of the day, and in the afternoon, it is quite likely the wind may blow and school work be suspended. But in the evening again, when there is usually a lull, a second period of instruction will be carried out. In well-equipped schools, to meet such conditions as these, it is customary to provide two complete and distinct staffs, both of instructors and mechanics. One staff takes the morning spell of work, while the second is held in readiness for the evening. This ensures that, both morning and evening, there shall be available for instruction a fresh, alert, and unfatigued staff.

In the next stage, a more interesting one, the pupil, occupying a seat immediately behind his instructor, is taken for a series of passenger flights. These accustom him to the sensation of being in the air, and also train his eye in judging heights and distances. A minor point the pupil should bear in mind, though his instructor will be quick to remind him, is not to wear any cap or scarf that may blow free in the rush of wind and become entangled with the propeller. Scarves need to be tightly wrapped; while it is usual, with a cap, to turn it with the peak to the back, and so prevent it from having a tendency to lift from the head. Many pupils provide themselves with a helmet designed to protect the head in case of an accident, and these are held firmly in position. Should a passenger's cap blow off, and come in contact with the propeller, it may be the cause of an accident. How carelessness may lead to trouble, in this regard, will be gathered from the following incident.

Some slight repairs had been made one day to the lower plane of a machine while it stood out on the aerodrome, and one of the workmen, through inadvertence, had left lying on the plane, near its centre, a roll of tape. The pilot decided to make another flight, and the motor was started and the machine rose. Suddenly the aviator was startled by a sound like a loud report, which seemed to come from the rear of his machine. The craft trembled for a moment, and he feared a structural collapse. Nothing worse happened, however, and he was able to pilot his machine in safety to the aerodrome. What had happened, it was then ascertained, was that the roll of tape, sucked back in the rush of wind, had been drawn into the revolving propeller and had broken a piece out of it. Luckily the impact had not been heavy enough to damage the propeller seriously, or cause it to fly to pieces.

A problem with which the pupil will be faced in his first flights, particularly if he is learning in winter, will be that of keeping himself warm. The speed at which an aeroplane travels, combined with the fact that it is at an elevation above the ground, renders the "bite" of the cold air all the more keen, and makes it difficult very frequently, even when one is warmly clad, to maintain a sufficient warmth in the body, and particularly in the hands and feet. The question of cold hands is, from a pilot's point of view, often a serious one. There is a case on record of an aviator who, his hands being so numbed that his fingers refused to move, found he could not switch off his motor when the time came to descend; and so he had to fly round above the aerodrome, several times, while he worked his numb fingers to and fro, and beat some life into them against his body. At last, having restored their circulation to some extent, he was able to operate the switch and make a landing. While on active service in winter, after flying several hours at high altitudes, and in bitter cold, the occupants of a machine have descended in such a numbed condition, despite their heavy garments, that it has been found necessary to lift them out of their seats. But a pupil need not face such hardships as these. He will be flying for short periods only, and at low altitudes; so if he makes a few wise purchases from among the selection of flying gear now available, and particularly if he equips himself with some good gloves, he should be able to keep sufficiently warm in the air, even if he is going through his training in winter.

The pupil's chief sensation, probably, will be that of the rush of wind which beats against him. Some people feel this much more than others. There is sometimes a feeling—it is no more than temporary—of inconvenience and of shock. The pupil feels as though his breathing was being interfered with seriously; as though the pressure was so great he could not expel air from his lungs. But this sensation, even when it is experienced, is short-lived. In a second flight, quite often, the novice finds that this oppression diminishes very perceptibly; and soon he does not notice it at all. Motoring experience proves useful here, particularly high-speed driving on a track.

Some confusion is felt by the pupil, as a rule, and this is only natural, in regard to the pace at which the aeroplane travels through the air, and at the way in which the ground seems to be tearing away below. Occasionally, in a first flight, this impression of speed, and of height, produce in the pupil a sensation of physical discomfort; but it is one again which, in the majority of cases, is quickly overcome. A few balloon trips are a useful preliminary to flights in an aeroplane. They familiarise one in a pleasant way with the sensation of height, and accustom the eye also to the look of the ground, as it passes away below.

While he is making his first flights with the instructor, and apart from analysing his sensations, the pupil will observe the lever movements made by the pilot in controlling the machine; and the fact that will impress itself upon him, as he watches these movements, is that they are not made roughly or spasmodically, but are almost invariably gentle. During these flights as a passenger, and after he has accustomed himself to the novelty of being in the air, the pupil will be allowed by the instructor to lean forward and place his hand on the control lever; and in this way, by actually following and feeling for himself the control actions the pilot makes, he will gain an idea of just the extent to which the lever must be moved, to gain any specific result in the flight of the machine.

A pupil continues his practice in "rolling" till he can drive his machine to and fro across the aerodrome on a straight course, and with its tail raised off the ground; the latter action being obtained by the pupil by means of a suitable movement of the vertical lever which operates his elevating planes.

Now comes the time when a pupil, taking the pilot's seat, and with the instructor sitting behind him—so as to be ready, if necessary, to correct any error the novice may make—begins his first short flights across the aerodrome. He rises only a few feet to begin with, and flies on a straight course, alighting each time before he turns, and running his machine round on the ground. He repeats this test until his instructor feels he is sufficiently expert to take the machine into the air alone. When this stage is reached, the instructor leaves his position behind the pupil, and the latter goes on with his practice till he can fly the length of the aerodrome alone, landing neatly and bringing his machine round on the ground, and then flying back again to his starting point.

In the early days of flying schools, before a pupil went through any regular system of instruction, there were remarkable incidents in regard to these first flights. In one case a pupil, having bought his own aeroplane from the proprietors of a school, insisted on having installed in it a motor of exceptional power. When the time came for him to make his first flight alone, and he opened the throttle of this engine and it began to give its full power, the aeroplane ran only a short distance across the ground, and then leapt into the air. The engine was in charge of the machine, in fact, and not the pupil. Away above the aerodrome, and beyond its limits, in a strange, erratic flight, the biplane made its way. As the pupil struggled valiantly with his engine switch, which appeared to have become jammed, he made unconscious and jerky movements of his control levers. One moment the machine would ascend a little, the next it would approach nearer the ground; then it would swing either right or left. Those watching from the aerodrome held their breath. But with the luck of the beginner, a luck which is proverbial and sometimes amazing, the pupil managed at length to stop his motor and land without accident—though by no means gracefully—in an abrupt gliding descent.

Another story concerns one of those temperamentally reckless, happy-go-lucky men who, though providence seems to watch over them, are an anxiety nevertheless to their instructors. This pupil, breaking the rules of a school, flew out on one of his first flights beyond the limits of the aerodrome, disappearing indeed from the view of those near the sheds. Not far from the aerodrome lay a main road, with tramway-lines along it. A tram, with passengers on top, happened to be passing down the road; and it was to the astonishment of these passengers, and to their perturbation as well, that they observed an aeroplane in full flight, moving very low across a neighbouring field, and bearing down straight towards them. The machine passed, indeed, unpleasantly close above their heads, and then vanished as dramatically as it had appeared. Its pilot, as may be guessed, was the pupil who had disobeyed orders, and was now on a wild and erratic flight. Presently, after swerves and wanderings over the surrounding country, he was discerned making his way back towards the aerodrome, still flying unreasonably low. Some trees bordered one end of the aerodrome; and towards these, as though he meant to finish his exploit by charging into them, the novice was seen to be steering an undeviating course. Nearer he came to them, and still he did not turn either right or left. The instructor, and those gathered with him, made up their minds that nothing could avert an accident. But it happened that there was, between two of the trees, a space only large enough for an aeroplane to pass through. A skilled pilot, a man of experience, would not have cared to risk his machine in an endeavour to creep between those trees. But this pupil, a complete novice, steered boldly towards the opening and slipped through it with a precision that would have aroused the envy of an accomplished pilot. Then he landed on the aerodrome and climbed in leisurely fashion from his machine—"not having turned a hair," as the saying goes. The remarks of the instructor when he neared the machine, and began to unburden himself, do not appear to be on record, and no doubt this is as well.

Having shown his ability to make a succession of straight flights, taking his machine into the air with precision and landing without awkwardness, the pupil finds himself faced next with the problem of turning while in the air. On this stage, however, he is not allowed to embark alone. The instructor takes his place again in the passenger's seat, so as to be ready to help the novice should he become confused, or find himself in any difficulty. Turns to the left are attempted first; and the reason is that, the propeller of the aeroplane revolving to the left—and the motor too if it is a rotary one—the machine has a tendency which is natural to turn in this direction. Half turns only are tried at first, the pupil landing before he has completed the movement. In making these first turns a pupil finds that, apart from his action with the rudder-bar, it is necessary to employ the ailerons slightly, so as to prevent the biplane from tilting sideways. The outer plane-ends of the machine have indeed, when a turn is being made, a natural tendency to "bank" as it is called, or tilt upward; the reason being that, as the machine swings round, these outer plane-ends, moving faster for the moment than the wing-tips on the inside of the turn, exercise a greater lift, and have an inclination to rise. An experienced aviator, having learned what is a safe "banking" angle, makes a deliberate use of this tendency when he is turning, and may on occasion even exaggerate it, to facilitate the swing of his machine on a very rapid turn, and to prevent it skidding outwards. But with the novice, engrossed completely as he is with the mere problem of getting his machine round in the air, "banking" is an art that must be deferred for awhile. It is perilously easy, for a beginner, to overstep the danger-line between a safe "bank" and a side-slip.

There are now certain very important rules which, in the navigation of his craft, he must accustom himself to bear constantly in mind. Should the engine of his machine, for example, betray any signs of failing, he must tilt down his elevator very promptly, and place his craft in a position for a descent. If he does not do this, and should the motor stop before he has his biplane at an angle for descent, the machine may lose speed so quickly, and its tail-planes show such a tendency to droop—owing to the lessening of pressure on their surfaces, consequent upon the failure of the motor—that there is a risk of the craft coming to a standstill in the air and then either falling tail-first, or beginning a side-slip that may bring it crashing to the ground.

The pupil must learn also, and this again is important, not to force his machine round on a turn while it is climbing. If he does so the power absorbed in the ascent, combined with the resistance of the turn, may so reduce the speed of the machine that it threatens to become "stalled," or reach a standstill in the air, with the result that it either side-slips or falls tail-first. The procedure the pupil is taught to follow is this: when he leaves the ground he climbs a little, then he allows his machine to move straight ahead; then he proceeds to ascend again for a spell, repeating afterwards the horizontal flight. In this way he ascends by a series of steps, like climbing a succession of hills in a car; and his turns should be made only during the spells when he is flying horizontally.

In this stage of his tuition, the pupil must learn also to make a vol-plané, or descent with his engine stopped. The essential point to be borne in mind, here, is that an aeroplane will continue in flight, and remain under control, even when it is no longer propelled by its engine. But what the aviator must do, should his engine stop through a breakdown, or should he himself switch it off, is to bring the force of gravity to his aid, and maintain the flying speed of his craft by directing it in a glide towards the ground. Provided he does this, and keeps his machine at such an inclination that it is moving at a sufficient speed through the air, he will find that the craft maintains its stability and that he has full command over its control surfaces, being able to turn, say, right or left, or either increase or slightly decrease the steepness of his descent. But all the time, of course, seeing that it is gravity alone which is giving him his flying speed, he is obliged to plane downward.

A story will illustrate this point; and it is one that has a special significance, seeing that the error which might have cost him his life was made by an aviator of experience. He had learned to fly on a monoplane, and had devoted his subsequent flying, for many months, to this one type of machine. Then he found himself associated with an enterprise in which a number of "pusher" biplanes were employed, and he decided that it would be useful for him to become accustomed to this type of machine. His flying experience of course helped him, and he soon found himself passing to and fro above the aerodrome, the biplane well in hand. Then he thought he would make a vol-plané, with his motor stopped, as he had been in the habit of doing in a monoplane. He switched off his engine without further thought, and moved his elevator to a position for the descent. But it was here that he made the mistake. In a monoplane, which has the weight of the engine and other gear well forward in the machine, the bow has a natural tendency to tilt down when the motor is cut off—particularly as the propeller-draught ceases to sweep under the sustaining planes. Therefore one can, in such a machine, switch off safely without first shifting the elevator, and getting the bow down as a preliminary. What the pilot had forgotten, for the moment, was the essential difference between monoplane and biplane. When he had switched off the engine in the biplane, and moved his elevator as he was accustomed to do, he found to his dismay that the machine failed to respond. Instead of pointing its bow down, indeed, it began to tilt rearward. Also, and this fact was noted by the airman with even more dismay, the craft lost forward speed so rapidly that it became uncontrollable. The next moment, the pilot helpless in his seat, the machine began a side-slip towards the ground. One sweep it made sideways, falling till it was not far short of the surface of the aerodrome. It paused an instant, then began a side-slip in the opposite direction. But here good fortune came to the pilot's aid. In this second swing, the machine being near the ground, it came in contact with the surface of the aerodrome before the "slip" had time to develop any high rate of speed. The biplane took the ground sideways, breaking its landing-chassis and damaging the plane-ends which came first in contact with the earth. But the pilot emerged from the wreckage unhurt. The accident was a lesson to him, though, as it was to others, and as it should be to all pupils. A machine must be in a gliding position before the engine is switched off.

The art of the accomplished pilot, granted there is no reason for him to reach earth quickly, is to glide at as fine an angle as is possible, consistent of course with maintaining the speed of the machine through the air, and so preserving his command over its controls. A beautifully-timed, fine glide, the machine stealing down gracefully, and touching the aerodrome light as a feather, at a precise spot the airman has decided on even when he was several thousand feet high, is a delightful spectacle for the onlooker, and a keen pleasure also—from the point of view of his manipulative skill—to the aviator himself. But a pupil, at any rate in his first attempts, must not concern himself too much with any idea of a fine or graceful glide. It is his business to get to the ground safely, and not trouble too much whether his method is accomplished, or merely effective. Once with the bow of his machine down, and his motor switched off, it must be his concern to maintain the forward speed of his machine, which can be done only by holding it well on its dive. For the novice, if he attempts any fine or fancy gliding, there is the very real danger that, in his inexperience, he may lose forward speed to such an extent that his controls become inoperative, and his machine threatens to side-slip. One's ear should, apart from the inclination of the machine, and the sensation of the descent, help one materially in judging the speed of a glide. There is a "swish" that comes to the ear, now the engine is no longer making its clamour, which gives a guide to the pace of one's downward movement. Aviators who are skilled, and have done a large amount of flying, are able to judge with accuracy, by the ear alone and without the aid of a mechanical indicator, what their speed is as they pass through the air.

Having held his machine firmly on its glide, till it is quite near the surface of the aerodrome, the pupil has next to think of making a neat contact with the ground. The art here is, at a moment which must be gauged accurately, to check the descent of the machine by a movement of the elevator—to "flatten out," as the expression goes. If the movement is made neatly the craft should, when only a few feet from the ground, change from a descent into horizontal flight, and continue on this horizontal flight for a short distance, losing speed naturally each moment—seeing that there is no driving power behind it—and so losing altitude also through its decrease in speed, until its wheels come lightly in contact with the ground, and it runs forward and then stands still. What the novice may do, if he is not careful, is to "flatten out" when he is too high above the ground. The result is that the machine slows up till it stands still in the air, robbed of its speed, and then makes what is called a "pancake" landing: it descends vertically, that is to say, instead of making contact with the ground at a fine angle and with its planes still supporting it; and the effect of such a "pancake," if the machine comes down with any force, may be that the landing-chassis is damaged, or perhaps wrecked. But as a rule, remembering that he has careful instruction to guide him before he attempts a gliding descent, the pupil masters the art of landing without difficulty, and without mishap.

Now, after repeating perhaps certain of his evolutions, at the discretion of his instructor, in order to make sure that he can accomplish them with ease, the pupil is ready for the tests which will give him his certificate of proficiency.

CHAPTER VI

THE TEST FLIGHTS

The sport of aviation is controlled throughout the world, and flying tests and events of a competitive character are governed, by the International Aeronautical Federation. To the deliberations of this central authority are sent delegates from the Aero Clubs of various countries; and to these Aero Clubs, each in its respective country, falls the task of governing flight, according to the rules and decisions of the central authority. In Britain, controlling aviation in the same way that the Jockey Club controls the Turf, we have the Royal Aero Club of the United Kingdom; and it is this body, acting in its official capacity, which grants to each new aviator, after he has passed certain prescribed tests, a certificate which proclaims him a pilot of proved capacity, and without which it is impossible for him to take part in any contests held under the auspices of the Club. The certificate, which is of a convenient size for carrying in the pocket, contains a photograph of the pilot for purposes of identification, and specifies also the rules under which the certificate is issued and held.

The theory of these tests, as imposed by the Club before it grants its certificates, is that the novice should—so far as is possible in one or two flights, made over a restricted area, and in a limited space of time—be called on to show that he has a full control over a machine in what may be called the normal conditions of flight. He is asked to ascend, for instance, and gain a fair flying altitude; then to make such evolutions as will demonstrate his command over the control surfaces of the machine; and finally to show that he can, with his motor switched off, descend accurately in a vol-plané, and bring his machine to a halt within a specified distance of a mark. The tests are set forth, officially, as follows:—