A second and smaller biplane, which serves both as rudder and lifting plane, extends about ten feet in front of the main planes. These two planes, which have a combined area of eighty square feet, may be inclined upward or downward by touching a lever at the pilot’s seat. The motor, radiator and petrol or fuel tank are placed on the lower plane in the center of the machine so that they balance the weight of the pilot and the passenger. The weight of the lifting planes and rudders rests on the main planes or lower deck.
PLATE XXIII.
A Well Built Model Badly Proportioned.
The most interesting feature of the Wrights’ airship is, of course, the method for flexing the tips of the wings or planes to imitate the flight of the birds. The ends of the large planes are made slightly flexible, and may be turned up or down by moving a lever placed convenient to the pilot’s hand. Both planes are flexed, or turned up or down, at the same time the vertical rudder moves, so that, when the aëroplane turns to right or left, the wings give the machine the proper balance. If it were not for this arrangement, the ends of the planes in turning would tend to rise, since they travel the faster, and the machine would be in danger of upsetting. The ends of the planes may also be flexed separately when the machine is in straight flight, whenever it becomes necessary to balance it against a dangerous air current or a gust of wind. The pilot, it will be seen, has every point of the great machine, as it were, at his finger ends.
The marvellous power placed in the hands of the pilot of one of these models makes him almost equal of the birds soaring about him. Let us suppose an accident to occur. Even should the engine stop, the skillful pilot is still master of the situation. He can actually coast down to the ground on the air with comparative safety. Mr. Orville Wright has soared up 3000 feet and, after stopping his propeller, slid down on nothing at all, at the rate of more than twenty miles an hour, by the force of gravity alone.
The Wright method of alighting is also borrowed from the birds. Watch any bird alight on a twig, and you will see that it always settles on the top of the twig, which is pressed straight down by its weight, and never sideways. As the Wrights come down, they approach to within a few feet of the earth, but, without touching they swoop up again, and finally settle down from a height of only a few feet. Considering the weight of their machine, they actually come down as lightly as a bird. While traveling at a speed of forty miles an hour they will skid along the ground or come to rest within five or six feet, so quietly that a passenger cannot tell when he lands.
No part of the aëroplane calls for more clever workmanship than the wings or planes. They must be so thin and light that they will ride the air like the wings of a bird, and yet strong enough to support the weight of hundreds of pounds of machinery and of passengers. In the Wright model, the planes are made entirely of wood, but so ingeniously braced that they are perfectly rigid. The building of such a wing is especially difficult, since it must be curved with scientific accuracy. In the Wright model machines, as in all aëroplanes, the curve is upward, with the highest point of the arch near the front or entering edge.
Both sides of the frame are completely covered so that they may offer the least possible amount of resistance. There is not a ridge, scarcely a seam, to catch the air. A stout canvas is used for covering. The ingenuity of these clever workmen led them to lay on the cloth with the thread running diagonally, at an angle of forty-five degrees. This plan serves to hold the frame more closely together and keeps the cloth from bagging or wrinkling.
At the first glance, the Wright machine appears to be made entirely of aluminium. Seen high aloft in the sunlight, it appears like some delicate jewel. The effect is due to the paint. The entire framework of the machine is made of spruce pine except the curved part of the wings, or entering edge, which is of ash. The propellers are driven by chains, connected with the motor, which run in steel tubes, thus doing away with the danger of fouling by passengers or loose objects. The ignition system is operated by a high tension Eisenmann magneto machine. The petrol used for fuel is carried in a tank placed above the engines and is supplied by gravity. The two wings are connected by a series of distance rods and wire cross-stays, which keep the entire front, or entering edge, and central part of the model, perfectly rigid.