Abstract: A helicopter rotor control system (13) including a stop azimuth controller (32) for establishing the value of a deceleration command (15') to a deceleration controller (23), a transition azimuth predictor (41) and a position reference generator (55), which are effective during the last revolution of said rotor (14) to establish a correction indication (38) to adjust the deceleration command (15') to ensure that one of the rotor blades (27) stops at a predetermined angular position.

Abstract: An electrically controlled (16) mechanical actuator (13) is driven by optically generated (23) electrical power through an optically controlled (28) switch (26) in an electrically isolated module (20). Optical transducers (54, 62, 70) and feedback (29), as well as optical inputs (40, 89, etc.) to electrical signal processing equipment (46, 47, 49) in an electrically isolated module (22) dictate the electrical control (28). A helicopter flight control system is wholly digital, with solar remote power and optical intercommunication.

Abstract: A four axis force stick provides signals indicative of force applied to the stick in an axis corresponding to a control axis of an aircraft, including pitch, roll, yaw and lift/speed. The force-related signals are applied through proportional and integral gain signal paths to operate electrohydraulic servos that control the aerodynamic surfaces of the aircraft, such as the cyclic and collective blade pitch of the main rotor and the tail rotor blade pitch of a helicopter, or the ailerons, rudder, elevator and thrust of a fixed wing aircraft. Signal conditioning provides a dead band to avoid integrating minute, inadvertent force stick signal outputs, and vernier sensitivity at low forces with high gain at high forces. Analog and digital embodiments are discussed. The relationship between this wholly new mode of aircraft control and ancillary aircraft functions, such as ground steering, autopilot and stability functions, are also discussed.

Abstract: The gain of a stability augmentation system for an aircraft, particularly a helicopter, is automatically varied in accordance with the gross weight and deviations of the center of gravity of the aircraft. Gross weight and center of gravity are identified from in-flight measurements of collective and cyclic pitch stick position and airspeed. The gain of the stability augmentation system will not be changed during periods when the aircraft is being maneuvered.