Book 3 — How to Make Propeller Blades Quickly
Reading edition
Requiring a number of propeller blades for use in making models of windmills, and other constructions, I found that I could save much time and obtain a satisfactory set of propeller blades by using ordinary shoehorns of the same size. The small ends of the horns were flattened out so that they could be fastened to pieces of wood for bearings, and then hammered to the proper shape for cutting the air, or receiving the force of the wind.