GB773803A - Automatic steering system - Google Patents

Abstract

773,803. Automatic steering control systems. BENDEX AVIATION CORPORATION. July 14, 1954 [Aug. 25, 1953], No. 20582/54. Class 38(4). In an aircraft control system the torque applied to a control surface in response to a control signal of a given magnitude is varied in dependence on the angular position of a trim tab associated with the control surface. In an aircraft automatic pilot, Fig. 1, a pick-off 11 associated with a gyro-vertical 13 produces, on pitch deviation of the aircraft, an A.C. output which is applied through a triode valve amplifier stage 29 to render one or other of triode valves 41 or 42 conductive, according to the sense of the deviation, so as to energize a control winding 72 or 73 of a saturable transformer 60 or 61. As a result, opposed secondary windings 67, 68 are unbalanced to produce an output which energizes one phase winding 77 of a two-phase servomotor 15 so that it runs in the appropriate to correct pitch by operation of elevator 22. A second two-phase servomotor 21 operates simultaneously to adjust the position of a trimming control surface 23 in the opposite direction and thus provide any force required to maintain any deflection of elevator 22 necessary to compensate for shift, forward or aft, of the centre of gravity of the aircraft. Servomotor 21 adjusts a rheostat 102 controlling the energization of the other phase winding 80 of servomotor 15 so that the maximum torque of the latter is dependent on the angular position of trimming control surface 23. In a modification, servomotor 21 adjusts a variable inductive transformer instead of rheostat 102 to control the energization of winding 80. A stabilizing follow-up signal is provided by a variable inductive transformer 85 adjusted by servomotor 15. Specification 671,336 is referred to.