Fig. 53. Connections of propeller blade
"The propeller blades ([Fig. 52]) are made of thin aluminum. Two sheets are cut out the same size and shape, and placed with their ends overlapping (see [Fig. 53]). A piece of steel wire 1⁄16 inch in diameter is bent and placed between them to form the shaft. The whole is then fixed in a piece of light copper tube, which is slotted by means of a hack saw or fret saw to receive them. The blades are bound crosswise to the tube by means of thin wire or strong thread; then twisted to a pitch of about 6 inches. It is also advisable to place a washer between the copper tube and the end bar of the frame.
"This method of fixing the propeller blades is not the same as that shown in [Fig. 50] but it is the better way.
"The drive for the propeller is elastic (a rubber band), which, when twisted and released, will rapidly revolve the shaft for a short time. The best kind to use is the gray variety, and when in the form of bands, say 3⁄8 inch by 1⁄16 inch by 6 inches, is ready for use without jointing. The wire carrying the elastic should be made so that the elastic is just in tension when untwisted.
"The monoplane, when complete, should be tested without the propeller until it will glide perfectly. The front of the plane will need weight added if there is a tendency to somersault; but if the back rises ahead of the forward end, more weight is necessary there. The best glide to be expected is about a 1 in 6 slope. The propeller should then be tried, and a flight of 50 or 100 feet, or more, should result. If there is a tendency to twist, owing to the side pull of the propeller, a screw should be fixed to the end of the plane to counteract it.
"A much longer flight can be given the model, if the spring is made so that the tension may continue a longer period. Sometimes a rubber attachment can be applied and twisted so that the propeller can be kept running long enough to carry the machine a much greater distance than here stated. The dimensions of all the parts of the machine are marked on the illustrations, so that you will find no difficulty whatever in making a model monoplane that will fly from the start. In the making of little models of this kind, you will encounter many things that will tax your skill and ingenuity, as amateur workmen.
"Now, children, I have told you all about aeroplanes that I intended, though I may take up the subject again, when I try to explain the recognized theory of flight, and the making and flying of kites."