GB1450076A - Control systems for gas rubine engines - Google Patents

Abstract

1450076 Controlling aircraft power plant ROLLS-ROYCE (1971) Ltd 29 March 1974 [5 April 1973] 16259/73 Heading B7G A control system for a gas turbine engine 30 which is provided with thrust reversing means 34 comprises power selector means 1 adapted to control engine power and thrust control means 2 adapted to adjust the thrust reversing means 34, the control means 2 also being adapted to vary the power from the engine whilst adjusting the thrust reversing means irrespective of the degree of power selected by the selector means 1. The engine has a shut-off control actuated by linkwork 68, 69 and a fuel control unit actuated by a lever 60 and chain and sprocket drive 61-63. The thrust reverser is actuated by an air-motor 94 supplied with air from the engine compressor through a one-way valve 92 and a spool 73 which is controlled by linkwork 47 and lever 74 mounted on a pivot 75 carried by a screw 76 to provide feedback. The power selector 1 which is released by depression of a handle to free rachet device 85, 86 is movable between position 16 (maximum power for take-off), position 17 (maximum continuous power), position 18 (flight idle), position 19 (engine start) and position 20 (engine shut-off). The selector incorporates two cam slots 52 and 64 within which are respectively positioned rollers 51 and 65, roller 51 being connected by link 59 to the fuel control drive and roller 65 being mounted on a lever 66 pivoted at 67 and connected to the shut-off control drive. The thrust control means 2 is movable between position 10, where it selects take-off power irrespective of the position of selector 1, position 11 which reduces the power of the engine to the level set by selector 1, between positions 11 to 13 to cause the thrust reverser to deploy at the power selected by power selector 1, between positions 13 to 14 to cause full deployment of the thrust reverser together with a progressive increase in power over that selected by selector 1. Final movement to position 15 continues to increase engine power to a maximum with the reverser in full reversethrust position. A stop 4, provided by a lever 77 recessed at 78 to receive a plunger 79, is mounted to hold the control at position 11 and is released by upward movement of a rod 80 operated during aircraft descent, e.g. by landing flap mechanism. A further stop 5 provided by a lever 81 holds the control at a position 12 corresponding to aircraft descent and this is released, e.g. by aircraft undercarriage compression. The operative connection between the power and thrust controls is provided by cam tracks 41 and 42 in control 2 engaged respectively by rollers 44 and 57, the former being mounted on one end of a pivoted lever 45 which is connected to linkwork 47 and the latter being mounted on a pivoted lever 55 which is connected by link 54 to roller 51.