Then the forward tilting plane was elevated slightly and the propeller wound up. On being released the aeroplane slowly and majestically sailed through the air in a great circle, limited by the length of the suspending thread.
The boys never tired of this toy and all it lacked was the ability to fly in the open air, which would require a more powerful motor. This would more than double the weight of the machine, and therefore call for larger planes to support it. There you have the great problem of the aviator.
Ralph wisely suggested that as they had not yet reached the stage of designing gasolene motors they had better leave the aeroplane as it was, or it would be necessary to abandon their woodwork, which neither of them had any intention of doing.
[IX]
THE MONOPLANE
A very satisfactory monoplane can be made from the plans shown in [Fig. 49].
The material for the frame should be quarter-inch white pine or spruce. The six long strips are 30 inches in length, and for fastening, holes should be drilled and the connection made by passing fine soft wire through them and binding fast.
The top frame, formed of four of these long strips, should be made first, with particular attention to the measurements, so that both sides shall be exactly the same size and weight.
At the rear end the two long strips may be wired together temporarily. The propeller shown in the drawing can be made at any time from a piece of white pine 7⁄8 inch thick and 12 inches long by 13⁄4 inches wide. It is a good piece of whittling work.