“Rolling” accomplished, and a facility gained with his control levers, the pupil is subjected to his first real test. Again alone in the machine, and with the instructor watching him from the sheds, he attempts a short, straight flight. There is nothing ambitious about this journey through the air; those on the aerodrome, in fact, call it a “hop.” What the pupil does is to accelerate his motor, attain a flying speed, and very cautiously move his elevator until he is skimming through the air a few feet above the ground. Then, after flying a short distance in this way, he pushes forward his lever and descends. He attempts no turns; rises no height in the air; the idea, indeed, is to learn the art of ascending and alighting with the least possible risk. Occasionally, and more often in the early days, a novice has shown an abnormal skill. One, ascending for the first time and ignoring the advice of his instructor, passed straight away from the aerodrome, rising as he flew, and disappeared above a clump of trees, his landing wheels almost brushing their tops. His instructor, and the officials of the ground, were naturally perturbed; particularly when, a minute or so later, the pupil was seen to be returning towards the aerodrome, flying now so low that he could not hope to clear the trees. Towards them he came, making no attempt to turn, and those who watched feared a fatal smash. But then an extraordinary thing happened. Despite the fact that he was an utter novice, and had made no flight like this before, the pupil steered coolly for a gap between two trees, and although there was barely room for his wing-tips, and he actually brushed against the branches upon one side, he managed to pass through safely and landed upon the aerodrome without mishap. When the instructor and others came over to him, expressing their astonishment, he appeared surprised that his performance should have provoked comment. Quite calm and unmoved, he seemed to think he had done nothing at all peculiar; although, as a matter of fact, such a flight between two trees—with practically no margin for error—would have been a feat considered perilous even by an experienced airman.
PLATE XV.—VIEW FROM A CRAFT ASCENDING.
In this picture the machine has only just left the ground, and its occupants, peering down as it rises slantingly, see the spectators below grow smaller and more remote.
Once he can make a short, straight flight and land neatly, the pupil is ready to attempt a turn while in the air. A half-turn to the left is first essayed, and for the reason that it is more easily accomplished than a swing to the right. This is due to the fact that the engine and propeller, revolving to the left, tend naturally to incline a craft in that direction. The pupil finds as he turns that he must—in addition to putting over the rudder—move the ailerons at his wing-tips; and he needs to make this movement because the biplane, while it is in the act of swinging, begins to heel inwards. The outer plane-ends of a machine, when it is forced thus upon a turn, have indeed a natural inclination to “bank,” or rise. This is because, as the craft swings, the outer wing-tips move more rapidly through the air than do those upon the inside of the turn; they exercise, for the moment, therefore, a greater lifting power; and the result is that, with this sudden and extra “lift,” they force up the outer side of the machine. On a very rapid turn, if this movement went unchecked, a machine might heel to such an angle that it slipped inwards and fell to the ground; but there is no fear of this if the pilot, moving over his hand-lever, draws at the ailerons upon the side of the craft that is tilting down. This causes the plane-ends to rise, and the machine swings upon a normal path. [Fig. 96] shows a school biplane making a “banked” turn. A certain amount of “banking” is necessary when turning; it helps a craft to incline smoothly and prevents it from skidding outwards, as it might do were its planes not heeling to the swing. Any pronounced degree of “banking” must not, however, be indulged in by a pupil. In even an acute “bank,” to a skilled pilot, there is no element of risk; experience has told him, in a way nothing else could, just what angle may be safe, or what not; but the beginner, remembering that any steep inclination of his planes may cause a side-slip, must not venture so to heel his craft. Sometimes, becoming over-bold, a novice may “bank” steeply once or twice without mishap; but then perhaps, while attempting to repeat the manœuvre he had made before, he may pass without knowing it over the danger-line, and find his craft slipping helplessly beneath him. If flying quite near the ground, as probably he will be, the mishap may mean a crumpled wing and nothing worse; and it will serve the purpose of teaching him a greater caution.
Fig. 96.—Banked turn on a biplane.
A.A. Represent the ailerons, which are drawn down by the pilot to prevent the machine from heeling too far inwards.