GB635592A - Improvements in control systems for rotative winged aircraft - Google Patents

Abstract

635,592. Fluid-pressure servomotor-control systems. AUTOGIRO CO. OF AMERICA. Aug. 8, 1947, No. 21886. Convention date. July 5, 1941. [Class 135] [Also in Groups XXXIII and XXXVIII] An aircraft sustaining rotor control system includes a rotor control element subject to rotor loads and movable under the influence thereof, a pilot's control member, mechanism interconnecting said element and said member whereby positional correspondence between the element and the member is substantially achieved, said mechanism including a servomotor arranged to assume a portion only of the rotor loads, the remainder of said loads being carried by the mechanism to the pilot's control member whereby the pilot is able to retain a sense of control " feel." The rotor 4, which may be driven or autorotative, is supported by a hub casing 17 arranged for tilting about a gimbal mounting 6. An arm 18, attached to the casing 17, is universally connected at 20 to a control rod 19 pivoted at its lower end 19a to an arm 21. The latter-mentioned arm is directly connected at one end 22a by a rod 22 to a pilot's control member 25 and at the other end 23a to the piston-rod 23 of a doubleacting fluid-pressure servomotor 29, 30. Pivoted at 46a to the rod 19 is the cylinder casing 45 of a " self-lapping " valve of which the extremity of the piston-rod 50 is pivoted at 51 to the arm 21. A reservoir 33 supplies fluid to two pumps 34 and 35 respectively driven by the rotor head 17 and the engine (not shown). The pump delivery pipes 39, 40 are connected through non-return valves 41, 42 and a pipe 44 to the valve 45, which is in turn connected to the servomotor cylinders 29, 30. The lapping action of the valve 45 is sufficient to permit small variations in the inclination of the rotor head to be transmitted directly to the pilot's control member without causing actuation of the servomotor in order to retain control sensitivity during normal flight conditions. Movement of the member 25 will cause the arm 21 to rock about the pivot 23a and actuate the valve rod 50. " Follow-up " action of the servomotor will then rock the arm 21 about the pivot 22a and actuate the rod 19 to tilt the rotor head. The pivots on the arm 21 are so positioned that the pilot's control member carries less than half of the rotor loads, the remaining proportion of the loads being carried by the servomotor in order that the pilot may retain a sense of control " feel." The arrangement described for longitudinal control of the rotor head is duplicated to provide transverse control thereof. Specifications 393,976 and 420,322, [both in Group XXXIII], are referred to.