Hughes Helicopters, Inc.

Summa Corporation

Andrew H Logan

Richard E Moore

Robert A Wagner, Deceased

John D Graves

Autorotation in helicopters at low altitudes can be achieved even when the inherent design of the helicopter would prohibit successful entry into the autorotation mode. Angular kinetic energy from the main propulsion engine is stored in a flywheel which automatically transfers this energy to the main drive shaft in the event of engine failure. During normal operation, the flywheel is driven through the main drive shaft by coupling to a secondary drive shaft. The main drive shaft in turn is driven by the engine through an overrunning clutch assembly. The flywheel is maintained within an evacuated housing whereby air drag is substantially eliminated. In the event of engine failure, the overrunning clutch disengages the engine from the main drive shaft and flywheel will continue to apply energy to the main drive shaft through the secondary drive shaft to permit autorotation and a no-damage landing even at low altitude flight levels.

Helicopter auxiliary energy system

Each landing gear of the undercarriage of an aircraft includes an hydraulic cylinder, and the hydraulic cylinders are interconnected through hydraulic restoring devices. The hydraulic restoring devices yieldably urge the pistons in each of the hydraulic cylinders to an equilibrium position, thereby restoring the length of each landing gear to an equilibrium length following a disturbance. In non-level landings, the hydraulically interconnected system causes the landing gear that strikes the ground first to be compressed and the other landing gears to be extended; this absorbs some of the energy of the impact. Extension of the other landing gears tends to limit the extent to which landing energy is converted to angular velocity of the aircraft caused by pivoting of the center of gravity of the aircraft about the first landing gear to contact the ground. Once all of the landing gears have contacted the ground, the restoring device acts to restore the aircraft to its normal equilibrium attitude with respect to the ground. In the event a non-level landing is aborted after one of the landing gears has struck the ground, the restoring device restores the landing gears to their normal in-flight configuration with respect to the airframe as the aircraft becomes airborne again in preparation for the next landing attempt.

Landing gear energy distribution and righting system

An antitorque system for use in a helicopter produces antitorque moments with efficiency comparable to that of the tail rotor it is designed to replace. The antitorque forces are generated mainly from the main rotor downwash by the circulation control effect. The downwash is deflected laterally as it passes around the tail boom by a sheet of air continuously discharged tangentially to the surface of the tail boom on one side of it at velocities in the range 30 to 120 meters per second from slots extending longitudinally along the tail boom and having a width in the range 4 to 20 millimeters. The discharged air is supplied by a relatively low-pressure-ratio fan within the fuselage which directs a stream of air rearwardly into the tail boom. The tail boom is provided at its rear end with a laterally disposed aperture through which some of the fan-supplied air is discharged to create a direct jet thrust. The flow through the aperture is throttled to vary the antitorque moment for trim and maneuvering.

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Rancho Palos Verdes, CA, United States of America

Andrew H Logan