Patent GB-846703-A (GB)
Title: Improvements in or relating to aircraft controls
Inventor: FLETCHER ARTHUR HOLMES
IPC: F02K1/76
Filed: 1956-10-05
Abstract: 846,703. Controlling aircraft. ROLLS-ROYCE Ltd.., and MATHERS, J. H. Sept. 23, 1957 [Oct. 5, 1956], No. 30511/56. Class 4. A control arrangement for aircraft power plant having thrust reversing means (e.g. reversible pitch propellers or propulsion jet deflecting means) comprises a pilot's control lever movable between full forward thrust and full reverse thrust positions through an idling position, means actuated on movement of the control lever through the idling position to effect appropriate adjustment of the thrust reversing means, a fuel supply control member moved by the pilot's control lever, and means actuated by the control lever on movement through the idling position to render the fuel supply control member incapable of increasing the fuel supply above a low value whatever the setting of the pilot's control member, and also actuated by movement of the thrust reversing means to the chosen position, to be rendered inoperative so that it can no longer prevent increase of fuel supply. In the embodiment described, a jet propulsion engine (not shown), has its exhaust deflectable to provide reverse thrust. The pilot's throttle control lever 10 is movable from a full forward thrust position A over a gate 12 at an idling postion B to a full reverse thrust position C. The lever drives a disc 14 with a cam slot 15 and a valve member 33 with a port 34, through a drive 13. A lug 16 on the disc takes up positions A, B, C, corresponding to the positions A, B, C, of the throttle lever, and is connected through a remote connection 17 to one end of a lever 18 pivoted at 19, the lever 18 taking up the full line position when the throttle is at A or C, and the broken line position when the throttle is at B. Lever 18 is connected to the engine fuel supply valve through a rod 21 and lever 20. The cam slot 15 contains a step 15c so that as the throttle lever moves through position B, a change-over valve 41 is actuated by a pin 42a in the slot and a piston 38 in a cylinder 37 is pneumatically operated to adjust the thrust reversing means to the inoperative or operative position, according as the throttle lever is moving towards position A or position C. The pivot 19 of lever 18 is motmted on the rod of a piston 23 in a cylinder 22, being urged to the right by a spring 24 but normally held in the position shown by hydraulic pressure in pipe 25, derived from the engine lubrication system or a constant delivery pump. Pipe 25 is connected by pipe 26 to a valve 27 which puts pipe 26 in communication with pipe 28 or pipe 29 depending on the position of a piston 30 controlled by the thrust reversal piston 38 through lever 36. Pipes 28 and 29 communicate with arcuate chambers 31, 32 in a fixed member 35 concentric with valve member 33, the interior of which is connected to a hydraulic drain. In the position shown, full forward thrust is obtained. On moving the throttle lever to position C, port 34 communicates with chamber 32, and pipes 29 26, and 25 are connected to the hydraulic drain. Piston 23 moves to the right, as does pivot 19, thus operating rod 21 so that the engine fuel supply cannot rise above the low value whatever the position of the throttle lever. Change-over valve 41 is operated on the throttle passing position B, operating the thrust reversal means. When the stroke of piston 38 is complete, piston 30 has covered pipe 29, pipe 26 is no longer connected to drain, and pivot 19 returns to its normal position, the fuel supply then being controlled solely by the throttle lever. Similarly, on returning the throttle lever towards position A through position B, pivot 19 is moved to the right by co-operation of port 34, chamber 31, pipe 28 and pipe 26, limiting the engine fuel supply, until piston 38 has completed its stroke rendering the thrust reversal means inoperative and restoring valve 27 to the position shown. The thrust reversal means may be reversible pitch propellers.