You now have the clock-works on the end of your shaft, and it is necessary to fasten a strip of pine 1⁄2 in. by 1⁄4 in. to the upper sticks of the frame in order to wire the works fast, as they must not be allowed to turn. By turning the propeller you wind up the clock, and as soon as you release it, as there is no escapement now to regulate the spring, it tries to unwind at once, and the propeller starts at terrific speed. Look out for your hands, as the propeller blades have no conscience.
This action, although strenuous, is short lived, but much more powerful than rubber bands. The spring of an ordinary alarm clock is powerful enough to drive a wooden two-bladed propeller 12 inches in diameter with blades two inches wide at the outside. It will draw a monoplane of this size along the floor several feet.
Having finally decided the question of power, it remains to attach the planes.
The remaining long strip is wired to the top pieces, 12 inches from the front, and the plane, made of silk, oiled paper, or very thin card-board, attached.
In many toy aeroplanes the bands of rubber are not stretched, but twisted. The shaft in this case is a wire which, after being fastened to the propeller, passes through a glass bead and then the frame, ending in a hook to which the rubber bands are attached. There must be a perfectly clear space from front to back of the frame. The glass bead between the propeller and frame is to relieve the friction.
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KITES
Making and experimenting with aeroplanes calls for much patience and often ends in disappointment—the lot of inventors generally. This is no reason why work should stop, as all progress is made by attempting the supposedly impossible, but it will be restful after a while to turn to the ancient and gentle art of kite making.
Incidentally, something may be learned about the effect of wind on plane surfaces that will prove helpful in aeroplane work.