autogyro -
an aircraft that is supported in flight by unpowered rotating horizontal wings (or blades); forward propulsion is provided by a conventional propeller
An autogyro, also known as gyroplane, gyrocopter, or rotaplane, is a type of rotorcraft which uses an unpowered rotor in autorotation to develop lift, and an engine-powered propeller, similar to that of a fixed-wing aircraft, to provide thrust. While similar to a helicopter rotor in appearance, the autogyro's rotor must have air flowing up and through the rotor disc in order to generate rotation. Invented by Juan de la Cierva to create an aircraft that could safely fly at slow speeds, the autogyro was first flown on 9 January 1923, at Cuatro Vientos Airfield in Madrid.
