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A heavier-than-air rotorcraft whose rotors are not engine-driven, except for initial starting. They are made to rotate by the action of the air when the rotorcraft is moving. The aircraft's means of propulsion, consisting usually of conventional propellers, is independent of the rotor system. Also known as an autogiro rotorcraft.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved