The ribs are made from the bamboo strips, cut the proper length and lashed to the front edge. The other ends are fastened to a cross-rib to make them take the same curvature. The lower diagram of Fig. 3 shows how the ribs are spaced.
Cover the wings with thin, strong paper. The best is Japanese paper, such as is used in making napkins. This is exceedingly light and very strong. It should be sewed, not gummed, as the gum makes the paper tear easily, and your sticky fingers spoil the whole cover very quickly. The paper is tough enough to be sewed, using a fine needle and white cotton, and you will get a neater and much more satisfactory job.
Make a triangle by lashing together three pieces of bamboo, two being about two inches long, and the third one inch. This triangle is lashed to the backbone just behind the wings, with the short side down; its position may be seen by a glance at the picture of the finished machine. It is kept rigid by running stays, made of waxed sewing-silk, from the lower corners to the stern-post, from the right-hand corner to the middle of the left wing, and from the left-hand corner to the middle of the right wing.
Just in front of this triangle fasten a piece of the bamboo, and make two small guiding vanes or rudders. These are made in a similar manner to the wings. Tie threads to the lower corners of the wings, and then to the triangle, drawing them down until they have the proper angle. The guiding-vanes should have a greater angle than the wings—that is, they should be drawn farther down.
It only remains now to make the screw and attach the rubber band. For the hub of the wheel you will need a small cork. This cork must be kept from turning on the end of the shaft. If the sharpened end of the shaft carrying the hook for the rudder was simply stuck into the cork, it would soon wear loose and turn easily. To make a firm hold for the shaft, bore a hole through the cork about a quarter-inch from the large end, and drive a plug of soft wood into this hole. The flat-pointed end of the shaft can now pass into the cork and be forced into the wood, being careful to have the end of the point parallel to the grain of the wood. This will give a firm hold and prevent the screw slipping.