GB644178A - Improved fluid-pressure control system for variable pitch propellers - Google Patents

Abstract

644,178. Variable-pitch propellers. GENERAL MOTORS CORPORATION. April 23, 1948, No. 11201. Convention date, June 14, 1947. [Class 114] [Also in Group XXIX] A variable-pitch propeller operating motor has pressure fluid supplied to one side of it only, under the control of a speed governor valve, this fluid being also led to a leak orifice controller by a pressure controlled valve. A steady pitch is maintained by the governor valve 22 applying like pressure to the space 46 through the offset Y. This offset also allows fluid to pass to the space 112 below the valve 74, and also to the leak 160. Line pressure from the line 10, together with the spring 96 holds the valve 74 down and vents pressure through ports 152, 154. The reducing valve 161 supplies reduced pressure to the space 48. When increased pitch is required valve 22 moves upward, increasing pressure in space 112 lifting valve 74 and closing ports 152, 154. If pressure demand is great, land 102 also closes the passage 118 to the leak. Fluid from space 48 lifts valve 161 and escapes through slots 195. To decrease pitch, valve 22 descends, venting lead 42 through ports 226. The movement of the piston 50 lowers pressure in space 191, causing valve 161 to descend and supplying fluid from line 70 through ports 187 to line 44 to move piston 50 further.