There are a lot of innovative aeronautical ideas of the past on this
web site: http://www.rexresearch.com/aero/1aero.htm

Those with a technical bent will find the information interesting.


"Remarkable Rotor Propeller For Airplanes"

59% increase in pulling power is claimed for an unusual new rotor
propeller for airplanes designed on somewhat the same principle as
the Flettner rotor sailing ship.