GB784088A - Improvements in or relating to aircraft - Google Patents

Abstract

784,088. Aircraft controls. HOBSON, Ltd., H. M., WESTBURY, R., and SMITH, C. P. Dec. 12, 1955 [Dec. 17, 1954], No. 36587/54. Class 4. A power-operated aircraft control comprises at least three electric signalling systems operable by the pilot's control, the servo motor having at least three inputs each operable by an electro-mechanical transducer mechanism and means for feeding signals from all the signalling systems to each transducer mechanism. In Fig. 1, the pilot's control member 6 operates the wipers 16, 16A, 16B of potentiometers 7, 7A, 7B, the signals derived being amplified by amplifiers 8, 8A, 8B respectively. The servomotor comprises a piston 2 anchored to the aircraft structure and working in a cylinder block 3 pivoted to the control surface 1. The block is movable under the control of three valve members 4, 4A, 4B operated by transducers 5, 5A, 5B, and co-operating with inlet ports 14, 14A, 14B and exhaust ports 15, 15A, 15B. Potentiometers 9, 9A, 9B move with the block and thus wipers 17, 17A, 17B derive surface displacement signals fed to amplifiers 8, 8A, 8B, so that the net input to each amplifier is a displacement error signal. The output of each amplifier is fed to one of the three inputs of each transducer, e.g. windings 11, 12A and 13B are fed from amplifier 8. The potentiometers 7 and 9 and amplifier 8 are energized from one source, and the other potentiometers and amplifiers are similarly energized from two other sources. The amplifiers 8, 8A, 8B saturate at an input level corresponding to a displacement error which is small in relation to the total stroke of the cylinder block. In a modified version, each transducer mechanism comprises three separate transducers, one energized by each amplifier Specifications 777,273 and 780,759 are referred to.