Page:Kitecraft and kite tournaments (1914).djvu/132

124 the ends of two pieces of wood, Fig. 258, a cut wide enough to take the thickness of the blank, and deep enough for the width, bend one blade forward and the other back, Fig. 259. The small clamps on the propeller blades should be placed at equal distances from the center, and should be given an equal amount of twist. The small clamps on the blades will not be forced over until they touch the base, so blocks of equal size should be used as stops in the operation of twisting. The clamps should be secured in the last position by means of cord to the base until the propeller is dry.

Still another way to attain the twist in veneer propellers, would be to have two blocks gouged out to the proper shape, one just fitting in the other. After the propeller is shaped in outline and steamed, it is placed between the two blocks, which are in turn clamped firmly together until propeller is dry.

Motors. Quite a number of devices have been tried, but the rubber string is by far the most efficient power yet discovered. Rubber has a great deal more power than an equal weight of steel in all ways that steel has been tried. The power of the rubber motor is dependent on the unwinding of the strands of rubber after having been wound up. The longer this unwinding may be delayed the further the little air