| 摘要 |
1,249,609. Deflecting propulsion jets. ROLLS-ROYCE Ltd. 20 Feb., 1970, No. 8164/70. Heading B7G. [Also in Division F1] A gas turbine jet engine comprises a variable area intake, a thrust reverser device which is adapted to reverse a selected proportion of the thrust producing exhaust of the engine, and control means which in one mode of operation cause the engine to produce the required thrust by running the engine at maximum speed, reversing a fraction of the thrust producing exhaust of the engine to provide a reduced thrust of the required amount, and closing the intake so as to produce a flow velocity of above Mach 0À8 in the intake. The engine shown is a ducted fan or by-pass type engine comprising LP compressor 10, IP compressor 11, HP compressor 12, combustion equipment 13, HP turbine 14, IP turbine 15 and LP turbine 16. The engine comprises a fan casing 19 which is provided with a variable area intake comprising flap members which are movable by actuator 22 to positions 23, 24, 25 for cruise, take-off and approach conditions respectively. A thrust reverser 26 is provided comprising an opening 30 in the fan casing and flap members 27, 28 which are movable by actuator 29, the flaps being shown in the full thrust reverse positions in which the flaps 27 block the by-pass passage and the flaps 28 direct the diverted air stream forwardly. In the approach condition the intake flaps are moved to the minimum area position 25, the thrust reverser is moved to a partial reverse thrust position and the engine is run at maximum speed resulting in large mass flow through the intake whereby the intake is partly choked. Once the aircraft has touched down the reverser is moved to the full reverse position whereby flow through the final nozzle is reduced, the pressure drop across the LP turbine is increased causing overspeeding of the fan, increasing the fan flow and so the reverse thrust. |
