Patent US 4,730,795

The basic characteristics of an airplane and of a helicopter are combined into one flying craft: a HELIPLANE. This aircraft can fly forward like an airplane and hover like a helicopter. In the hovering mode, the craft lifting force is generated by gyrating blades and the craft control forces and moments are provided by a tail end propeller. In the forward flying mode, the craft lifting forces are generated by two wings and the gyrating blades. The propeller alone provides the forward propulsive thrust. The operations of the gyrating blades, of the craft control surfaces and of the power plant are all integrated, monitored and controlled to coordinate such operations during hovering, forward flight and any transition phase between hovering and forward flight. The gyrating blades never generate any forward propulsive thrust. The cyclic pitch motion of the gyrating blades needed to accommodate the craft forward flight velocity is induced by this forward velocity. Opposite gyrating blades are free to rotate around their longitudinal axes of rotation, but are solidly and rigidly connected to each other, so that both blades in any pair are always forced to rotate together by the same amount and in the same direction. The collective pitch of the gyrating blades is adjustable to meet the requirements of altitiude, craft weight and rate of ascent changes which affect the upward lifting force needed. The complex dynamic behavioral response of helicopters to cyclic pitch variations, and the consequences thereof, are eliminated in the present invention. All control and actuating means of the gyrating blades are well protected and shielded from environmental hazards.