CONSTRUCTION
Propellersmay be cut from various kinds of wood, but the most suitable, from every standpoint, is white pine. The advantage of using this wood lies in the fact that the propellers may be cut more rapidly and when cut are lighter than those made from most other kinds of wood. When coated with the proper kind of varnish they are sufficiently strong for ordinary flying. Wood selected for propellers should be free from knots, holes and other imperfections and it is very desirable that it should be of perfectly straight grain.
A piece of such clear white pine 8″ long, 1″ wide and ³⁄₄″ thick should be selected and on one side markedTop. A tracing of the propeller similar in design toFigure 1, should be laid on this piece of wood and an imprint of the propeller design drawn on theTopside.