GB737812A - Improvements in and relating to artificial feel systems for aircraft controls - Google Patents

Abstract

737,812. Controlling aircraft. ENGLISH ELECTRIC CO., Ltd. March 5, 1954 [March 10, 1953], No. 6649/53. Class 4. In a feel simulator system the ratio of the restoring force upon the pilot's control member, for a given deflection from its neutral altitude, to the dynamic pressure, remains at a substantially constant value over a range of aircraft speeds up to nearly sonic speed and then falls off rapidly over the range of aircraft speeds through and above sonic speed. In one arrangement, Fig. 1, the pilot's control member 1 is coupled to the piston 6 moving in a hydraulic cylinder 3 pivoted! to the aircraft structure. A valve 31 controls the pressure of the fluid in the cylinder 3 and is operated by a lever 34 one end of which rests on the face of a capsule 35. The casing 37 within which the capsule is mounted is connected through a pipe 38 to a source of static air pressure. The interior of the capsule may be connected by a pipe 36 to a air intake 30 arranged on the surface of the fuselage or a nacelle and so proportioned and placed that at supersonic speeds its shock wave separates the boundary layer in front of it so that the excess pressure in the intake over the static pressure is substantially proportional to dynamic pressure up to nearly sonic speed and then falls off rapidly from this proportionality. The capsule 35 may be provided with an interior evacuated capsule which acts as a compression spring on the inside of capsule 35. In another arrangement, Fig. 5, the interior of capsule 35 is connected by the pipe 36 to a chamber 42 which is connected through a restricted orific 41 and pipe 40 to a pitot tube (not shown). The chamber 42 is also connected by a pipe 43 to the interior of a capsule 44 arranged within an evacuated capsule 45. A chamber 46, within which capsule 45 is placed, is connected to a source of static pressure by a pipe 48 and to the chamber 42 by a valve 47 which is controlled by the combined capsules 44, 45. Spring 49 loads the capsule in the sense of tending to close valve 47. By suitable arrangements of the geometry and the spring rates'of the capsules and the spring, the valve 47 can be arranged to open near sonic speed and the pressure in the chamber 42 and pipe 36 can be made to follow the required characteristic. Specification 727,513 is referred to.