Abstract: A lift rotor assembly for a compound aircraft having a fuselage, including at least one circular disk structure with a plurality of bladelets spaced peripherally thereabout, a drive shaft coupled to a power source at a first end for rotating the drive shaft at low torque, a hub coupled to each circular disk structure and being located concentrically about the drive shaft, a gear drive coupled to a second end of the drive shaft opposite the first drive shaft end, and a first gear coupled to the gear drive and the hub for the circular disk structure located adjacent to the gear drive, wherein the first gear is operated at high torque to rotate one of the circular disk structures. The lift rotor assembly also includes a gear reduction apparatus associated with the gear drive in order to operate the first gear at high torque, as well as a constant velocity joint connecting an upper portion and a lower portion of the drive shaft.

Abstract: This invention relates to autogyros and to counter-rotating rotor helicopters. It further relates to compound autogyros and/or helicopters that employ a lifting surface or wing in forward flight. More specifically this invention provides an autogyro with counter-rotating rotors, circular planform wing integral with the rotors, and means for engaging power to the rotors for vertical ascent, descent and hovering.