GB796453A - Aircraft control system - Google Patents

Abstract

796,453. Automatic aircraft control systems. BENDIX AVIATION CORPORATION. April 13, 1956 [April 21, 1955], No. 11356/56. Class 38 (4). In an aircraft automatic pilot, an auxiliary control surface pivoted to a main control surface to apply aerodynamic loading to it, is motoroperated in accordance with a control signal and two follow-up signals, one of which is derived in response to movement of the motor and the other is derived in response to movement of the main control surface. As shown, variations in the pitch attitude of an aircraft are detected by a vertical gyro 10, signals from the inductive pick-off 12 of which are applied through an amplifier 14 to operate a reversible induction motor 15 controlling an auxiliary elevator control surface 73 through gearing 43 and an electromagnetic clutch 44. The aerodynamic loading on auxiliary control surface 73 when operated causes movement of the main elevator control surface 75 to correct pitch. The following negative feedback signals are applied to the input of amplifier 14:-(a) Positional feedback from an inductive device 20 operated by motor 15. (b) Rate feedback from a generator 16 driven by motor 15. (c) Positional feedback from an inductive device 22 operated by the main control surface 75. (d) A feedback dependent on the torque of motor 15 from an inductive device 18 operated by movements of the spring- restrained stator of motor 15. The signal dependent on motor torque derived from inductive device 18 is also applied through an amplifier 14<SP>1</SP>, motor 15<SP>1</SP>, gearing 43<SP>1</SP> and clutch 44<SP>1</SP> to operate, slowly, an elevator trim tab 90. If a switch 120 is opened to de-energize clutches 44, 44<SP>1</SP> and disengage automatic control, auxiliary control surface 73 and hence main control surface 75, may be operated manually by a controller 85, motor 15 then maintaining the input to amplifier 14 zero in readiness for re-engagement of automatic control without shock. If the torque of motor 15 exceeds a predetermined value, limit switches 113 associated with the spring-restrained stator of motor 15 de-energize clutches 44, 44<SP>1</SP> to disengage automatic control. Integral construction of the gearing, clutch and motor torque measuring gear is described. Specification 662,831 is referred to.