Shortly before his death at the age of thirty Penaud revived a sort of "Chinese top", with one original feature. Motive power was provided by pieces of twisted indiarubber - a method still in use today by aero modellers.

This aircraft had two contra-rotating rotors.

P.Lambermont "Helicopters and Autogyros of the World", 1958


Another notable French experimenter of this time was Alphonse Penaud. Around 1870 he built a number of high-flying model helicopters, all fashioned after the manner of the Chinese top. Powered with twisted rubber bands, several of his models climbed to heights of more than 50 feet. Penaud's experimentation and model-building activity was not limited to helicopters alone: he designed and constructed tiny rubber-powered airplanes and ornithopters (wingflappers) that also flew exceedingly well.


G.Apostolo "The Illustrated Encyclopedia of Helicopters", 1984