GB619988A - Improvements in flying controls for aircraft - Google Patents

Abstract

619,988. Aircraft control systems. SAUNDERS-ROE, Ltd., KNOWLER, H., and SWAIN, A. E. Oct. 16, 1946, No. 30808. [Class 4] [Also in Group XXXII] In order to simulate " feel " in the poweroperated control system of an aircraft, a force which increases with movement of the pilot's control member 10 and also with airspeed is applied to the control member by connecting it to a piston 15 movable in a cylinder 16, both ends of which receive liquid from a pump 12, the liquid exhausting through two valves 23 whose extent of closure is governed by the two factors mentioned above. The control member 10 is connected to the piston 15 by a rack and pinion 13, 12 and the pressure on each side of the piston 15 is governed by the valves 23 between the delivery of the pump 18 and a reservoir 19. Normally, the valves 23 are open to the same extent so that there is no force on the piston 15, but as the control member 10 is moved from its neutral position, a rack and pinion connection 30, 31 to rod 29 causes this rod to move a lever 27 engaging a slot in rod 29 about its pivot 28, so moving a member slotted to receive the lever 27 and on which both valves 23 are mounted, to close one of the valves 23 and to open the other. A force is thus set up on piston 15 which corresponds to the movement of the control member 10 and tends to return this member to its neutral position. The rate at which this force increases with increase of movement of the member 10 is caused to increase with airspeed by mounting the pivot 28 on a strap 32 depending from a pressure-sensitive capsule 33 connected at 34 to a pitot tube measuring the dynamic head of air. In two further constructions, the valves 23 are operated by a follower bearing on a three-dimensional cam: in one, the cam is moved axially by the piston 15 and rotated by a rack and pinion connection to the capsule 33, in the other the piston 15 is replaced by a vane rotatable to vary the volumes into which a cylinder is divided by a fixed axial partition and the cam rotates with the vane and is moved axially by the capsule 33. Specification 619,984 is referred to.