autogiro

autogiro or gyroplane , type of aircraft supported in the air by a horizontally mounted airfoil similar to that of a helicopter but unpowered. Invented by the Spaniard Juan de la Cierva, it was first flown successfully in Jan., 1923, in Spain. Most of the lift is supplied by large airfoils which are mounted horizontally above the craft and rotated by the airflow created by the craft's forward movement. The autogiro has fixed wings that are smaller than those of an ordinary airplane; the body and tail assembly is of conventional design. Thrust is supplied by an ordinary engine and propeller, and control is maintained by a rudder, elevators, and ailerons. In one type, fixed wings are absent, and the rotor provides all the lift. Control of pitch and roll are accomplished by tilting the rotor forward, backward, or to either side. Some advantages of the machine are that its descent will be slowed by the turning of the rotor if the engine fails; that it becomes airborne with a very short takeoff run and can land in small areas; and that with a moderate headwind it can virtually hover with zero ground speed. However, it cannot match the vertical climbing performance of the helicopter.

au·to·gi·ro / ˌôtōˈjīrō/ (also au·to·gy·ro) • n. (pl. -ros) a form of aircraft with freely rotating horizontal vanes and a propeller. It differs from a helicopter in that the vanes are not powered but rotate in the slipstream, propulsion being by a conventional mounted engine.