The blades of the screw are made of thin paper gummed on to short pieces of bamboo. Lay one of the bamboo spokes on a piece of thin, stiff paper, and then gum over it a small strip of the thin Japanese paper before referred to. When this is dry, cut it down to the proper shape and sharpen the end of the spoke. Force these spokes into the cork so that all the blades will turn the same way, as shown in the picture—_i. e._, so that when the screw is turned the blades will all strike the air in the same manner and tend to force the machine forward, not so that some try to push it forward and some backward.
Select a rubber band of the proper size—such a one as will stretch the length of the backbone easily and not be so strong that, when stretched, the backbone is bent into a bow. Tie this band to the forward support with a string, and then draw it back and slip it over the hook on the shaft.
To wind up the machine, hold it by the backbone and turn the screw the wrong way until the rubber is twisted tight. Then hold the machine up, let go the screw, and when it is revolving rapidly, give it a gentle push forward. If it pitches head-first, draw down the wings; if tail-first, let up the wings or turn the screw the other way. If the wheel does not revolve rapidly cut off part of the blades or use a stronger rubber. Some little adjustment of the kind is usually required before the thing moves properly.
A contrivance of this sort should be very light. The one before me has wings two feet from tip to tip, and it weighs when complete—backbone, wings, rubber, screw, etc.—only one-third of an ounce.