GB771623A - Improvements in or relating to aircraft - Google Patents

Abstract

771,623. Aircraft feel simulators. HOBSON, Ltd., H. M. Oct. 24, 1955 [Dec. 15, 1954], No. 36349/54. Addition to 734,437. Class 4. An aircraft feel simulator is as claimed in claim 1 of the parent Specification, and and the control valve 38 is a piston valve coacting with pressure and exhaust ports 39 and 40, the airspeed responsive device 44 applying pressure to the end of the control valve, in opposition to the hydraulic control pressure in the housing acting on the other end of the control valve, through the intermediary of a relief valve 49 held seated against the end of the control valve against the control pressure which is applied to the relief valve through a duct 50 therein by spring 43 assisted by the airspeed responsive device, so that the relief valve opens when the control pressure becomes excessive, and comprises a spring 55 acting on the end of the control valve subject to the control pressure in the direction to assist the control pressure. At very low airspeeds, the tendency for the valve to stick when the forces acting on it are very small is overcome by the spring 55. The simulator is substantially similar to that described in the parent Specification with reference to Figs 1 and 8 thereof, except that the spring 55 is added the strength of spring 43 being correspondingly increased, the duct 42 communicates the control pressure at port 28 to the lower end of the valve 38, and three springs 48 prevent the diaphragm 44 from contacting the push rod 45 at low airspeeds, instead of a single spring surrounding the push rod. A device or devices sensitive to airspeed or Mach number may be coupled to the diaphragm 44 to modify the characteristics of the simulator when a given airspeed or Mach number is attained. Specification 740,510 also is referred to.