Patent GB-1054216-A (GB)
IPC: F02K1/15
Abstract: 1,054,216. Gas turbine jet propulsion engines. SOCIETE NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS, D' AVIATION. April 16, 1964 [April 26, 1963], No.15876/64. Heading F1J. The invention relates to an accelerating arrangement for a gas turbine jet engine having a propulsion nozzle of variable cross-sectional area and in which movement of the rod of the distributor which controls flow of fluid to the actuator of the variable area nozzle is controlled, inter alia, by the movement of the pilot valve of the fuel control unit. The arrangement comprises on one hand, a yieldable follow-up device which is interposed in the connection between the control unit and the pilot valve thereof and which is compressible during movement of the connection in the direction to open the control unit, and on the other hand, in association with the fuel control unit, a releasable stop device which is rendered operative when an acceleration order is given to the pilot valve of the control unit so that the latter is fixed in position whilst the yieldable device is compressed during the time that the variable area nozzle is opened. The stop device is subsequently released thus releasing the control unit which can thus open under the action of the yieldable device as the latter expands. In Fig. 1, there is shown a flap 1 of a variable area jet propulsion nozzle, the flap being pivotally mounted at 2 and movable by means of an actuator 3, flow of fluid to the actuator being controlled by a spool valve 4. The position of the valve 4 is controlled by the pilot valve 6 which is associated with the fuel control unit 5, the rod of the pilot valve 6 being connected to the valve 4 by means of a lever 7 pivotally mounted at 8, a pressure capsule responsive to compressor inlet and compressor discharge pressures being disposed in the linkage. Interposed between the pilot valve 6 and the fuel control unit 5 is a yieldable followup device 14. The control unit 5 is also connected to a releasable stop device which comprises a piston 13 disposed within a cylinder 12, fluid being supplied to the chamber 11 above the piston, the fluid discharging therefrom through an outlet 18 which may be closed by a valve member 17. When the valve member 17 is closed, fluid cannot escape from the chamber and so the device acts as a stop to prevent movement of the fuel control unit 5. Movement of the pilot valve 6 to the right calling for increased thrust acts on the distributor spool valve 4 and actuator 3 to open the variable area nozzle 1, but movement of pilot valve 6 cannot adjust the fuel control unit 5 since this is locked by the device 12, 13. Movement of the rod of valve 6 to the right however, is absorbed by the spring in the yieldable device 14. When the valve 17 is subsequently opened so releasing fluid from the chamber 11, the piston 13 can then move to the right so permitting opening of the fuel control unit 5 by the energy stored in the yieldable device 14. A drain cock 15 is provided to the chamber 11 being caused to open by the device indicated at 15' when the variable area nozzle is in the fullyopen position. In a further embodiment, the piston and cylinder assembly 13, 12 is offset axially from the units 6, 14 and 5 - Fig. 2 (not shown) the connection between the fuel control unit 5 and the stop device 12, 13 being by means of a pair of levers 21, 19.