Aileron

“ It must be banked to prevent skidding, even as a race-track is banked high on the turns. On its side an airplane will cushion its own bank of proper degree by the use of ailerons. These ailerons are sections of the wing-tips which may be moved either up or down. ”

“ 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. ”

“ The rear edges near the tips of the aerofoil being dipped or tilted respectively, in order to create a temporary difference in their inclinations to the line of flight. Performed in conjunction with rudder movements, to counteract the excessive action of the latter.
Ailerons (also called "righting-tips," "balancing-planes," etc.) . ”

“ Through those in front the pilot may glance when descending from a flight, so as to judge his distance from the ground, while the others are utilised by the observer, as he turns to look from side to side. This biplane, and many others, is balanced against sideway roll by ailerons, and not by warping the wings. ”

“ Most aeroplanes have little planes called “ailerons,” which swing up and help to [Pg 30] balance the aeroplane when it tips. They are worked by the aviator, and if anything happens to him, or to them, very quick trouble follows. But with the tetrahedral’s many little planes, facing every way, the machine caught the air and righted itself no matter which way it leaned.
To all of this, Lieutenant Adeler listened without saying much. ”

“ Now the wings and fuselage of our airplane are ready, and the rudder, the elevating surfaces and the ailerons are in course of production. They are made in the same manner as the wings, with a wooden framework over which fabric is stretched and “doped.” We begin to think our big bird is almost ready to be put together, but we have forgotten two important items: the engine and the propeller.
The airplane manufacturer usually does not attempt to build his own engines or propellers. ”

“ 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. ”

“ This element of inherent stability is obtained by suitably grading the camber and incidence of the wings, until at the wing tips the chord of the plane section forms a negative angle to the line of flight. Although this arrangement is undoubtedly of value, especially for the touring machine of moderate power, its chief fault lies in the relatively slow righting movements, which, although of no great consequence at a reasonable altitude, becomes a source of danger when alighting, and certainly entail the use of ailerons, or warp, to counteract it. ”

“ 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 ”

“ These ailerons are so arranged that the front edge remains in the same position; while one swings upward, the other swings downward, at the back, thus giving an upward pressure of air on the under side of the one, while the other is depressed by the air which strikes it on top. This movement is controlled by a movable back to the aviator's seat or a frame or yoke which fits around the shoulders of the aviator in such a way that he moves the ailerons to the proper position when he leans to the high side of the aeroplane as it tilts and is thus able automatically to correct its balance. ”

“ In this the ailerons are used as previously described, but also there are side curtains enclosing the outer edges of the main planes. Out in front at the end of a long framework or fuselage are the horizontal elevating planes, and the vertical direction planes. Both these machines have double control systems. ”

“ But over hilly and wooded country the air is often flowing or rushing in conflicting channels, and the aviator does not know what he may be called upon to face from one moment to 163 the next. If the aeroplane starts to drop, it is only necessary to push the steering wheel forward a little—perhaps half an inch—to bring it up again. Usually, the machine will drop on an even keel. Then, in addition to the motion just described, the aviator will lean toward the higher side, thus moving the ailerons by the seat-back, and at the same time he will turn the steering wheel toward the lower side. ”

“ 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. ”

“ The balloon began descending to earth again, and soon the guide rope again rested on the ground. There was nothing to do but to bring the trip to an end, because only a few handfuls of sand remained to us.
He who wishes to navigate an air-ship should first practise a good many landings in a spherical balloon—that is, if he wishes to land without breaking balloon, keel, motor, rudder, propeller, water-ballast cylinders, and fuel holders. The wind being rather strong, it was necessary to seek shelter for this last manœuvre. ”

“ Watch the successful model as it gains its altitude, settles down to a horizontal flight, is perhaps knocked off its course by a cross current, and steadies itself with a graceful curve and proceeds on its way.
All these problems must be anticipated. The young aviator must ingeniously arrange his planes and ballast in advance. The regular sky pilot, on the other hand, meets the problems of the air as he encounters them, by flexing his wings against disturbing currents or by banking to maintain an even keel at a turn. ”

“ Evidently it would be a mistake to place the air-ship at a point suitable for an ordinary balloon without motor and propeller.
And yet it was there that I did place it, not by my own will, but by the will of the professional aeronauts who came in the crowd to be present at my experiment. In vain I explained that by placing myself "up stream" in the wind with relation to the centre of the open space I should inevitably risk precipitating the air-ship against the trees before I would have time to rise above them, the speed of my propeller being superior to that of the wind then blowing. ”

“ Its striking against the atmosphere makes a counter-pressure against the outside of the stem-head. Up to 30 kilogrammes to the square metre, therefore, all increase in the air-ship's speeds tends to reduce strain—so that the faster the air-ship goes, the less will it be liable to burst its head!
How fast may the balloon be carried on by motor and propeller before its head-stem strikes the atmosphere hard enough to more than neutralise the interior pressure ? ”

“ A spirited contest in the air is one of the grimmest and most thrilling spectacles possible to conceive, and it displays the skill of the aviator in a striking manner. Daring sweeps, startling wheels, breathless vol-planes, and remarkable climbs are carried out. One wonders how the machine can possibly withstand the racking strains to which it is subjected. The average aeroplane demands space in which to describe a turn, and the wheel has to be manipulated carefully and dexterously, an operation requiring considerable judgment on the part of the helmsman. ”

“ At every stage of this development the aviators are indebted to the birds for information. The successful aëroplanes have great width compared to their depth, they gain stability by flexing the tips of the wings, and their planes are arched upward and forward exactly as are the wings of a bird. The aviator arranges his center of gravity after the same general model, below the planes and well forward. He places his engine forward, just as the bird has its strongest muscles in the chest, and he builds his frame of hollow tubes like the bones of a bird. ”

“ Of course, when an aviator is lost in the fog or above the clouds he needs to use all the instruments on board to find his position. For that purpose drift instruments are mounted on aircraft; those tell how much the air-currents, which have the same effect on aircraft as the tide has on a boat, have driven him off his course. A compass indicates the direction in which he is travelling, and other instruments show him whether his machine is climbing, diving, or “banking”; the aneroid barometer indicates the altitude. ”

“ I lay in my customary glider position, horizontal and face downward, and the invisibility of all the machinery gave an extraordinary effect of independent levitation. Only by looking up as it were and turning my head back could I see the flat aeroplane bottom of the balloon and the rapid successive passages, swish, swish, swish of the vans of the propeller. I made a wide circle over Lady Grove and Duffield and out towards Effingham and came back quite successfully to the starting-point. ”

“ If you will scale a sheet of tin, or a thin, flat stone, or even a slate from a roof, into the air, you will have the simplest form of an aeroplane. The stone, or tin, is heavier than the amount of air it displaces, but it stays up for a comparatively long time because it is in motion. The moment the impulse you have given it by throwing fails, then it begins to fall.
The engine, or motor, aboard an aeroplane keeps it constantly in motion, and it glides along through the air, resting on the atmosphere, by means of the planes or wings. ”

“ HOW does it feel to travel in an air-ship? My first impression of aerial navigation was surprise to feel the air-ship going straight ahead. It was astonishing to feel the wind in my face. In spherical balloons we go with the wind and do not feel it. True, in rising and descending, the spherical balloonist feels the friction of the atmosphere, and vertical oscillation often makes the flag flutter; but in all its horizontal movements the ordinary balloon seems to stand still while the earth flies past under it. ”

“ Gliding Descent Without Propeller Thrust.—All aeroplanes are, or should be, designed to assume their correct gliding angle when the power and thrust is cut off. This relieves the pilot of work, worry, and danger should he find himself in a fog or cloud. The pilot, although he may not realize it, maintains the correct attitude of the aeroplane by observing its position relative to the horizon. Flying into a fog or cloud the horizon is lost to view, and he must then rely upon his instruments— (1) the compass for direction ”

“ The development of aeronautics generally in this country was behind that of the Continent, and the airship had suffered to a greater extent than either the seaplane or the aeroplane. Our attitude in fact towards the air had not altered so very greatly from that of the man who remarked, on reading in his paper that some pioneer of aviation had met with destruction, "If we had been meant to fly, God would have given us wings." ”

“ From observation he gathered how a bird checks its own speed by opposing tail and wing surface to the direction of flight, and thus alights at the proper ‘landing speed.’ He proved the existence of upward air currents by noting how a bird takes off from level earth with wings outstretched and motionless, and, in order to get an efficient substitute for the natural wing, he recommended that there be used something similar to the membrane of the wing of a bat—from this to the doped fabric of an aeroplane wing is but a small step, for both are equally impervious to air. ”

“ Hereby the force of the wing and the resistance become balanced; so that, manifestly, the air is beaten by the wing with the same force as the resistance to the stroke.’
He concerns himself also with the most difficult problem that confronts the flying man of to-day, namely, landing effectively, and his remarks on this subject would be instructive even to an air pilot of these days: ‘Now the ways and means by which the speed is slackened at the end of a flight are these. The bird spreads its wings and tail so that their concave surfaces are perpendicular to the direction of motion ”

“ Next, since the wings with their feathers attached form almost a plane surface, they are raised slightly above the horizontal, and with a most quick impulse beat down in a direction almost perpendicular to the wing-plane, upon the underlying air; and to so intense a beat the air, notwithstanding it to be fluid, offers resistance, partly by reason of its natural inertia, which seeks to retain it at rest, and partly because the particles of the air, compressed by the swiftness of the stroke, resist this compression by their elasticity, just like the hard ground. ”

“ Rarely from a favorable point of vantage on a mountain, and very frequently from aircraft, the specter, instead of being seen on a vertical wall of mist when the sun is low, appears on a horizontal sheet of cloud below the observer when the sun is high. The aeronaut may thus observe the complete outline of his balloon or aeroplane, encircled with the rainbow tints of the glory. During the World War the appearance of the luminous rings was likened to the emblem painted on the wings of the Allied aeroplanes and was regarded by superstitious aviators as an omen favorable to their cause. ”