Patent GB-770106-A (GB)
Title: Improvements in or relating to aircraft power plants
Inventor: HOLLINGS JOHN SHAW
IPC: B64D31/00
Filed: 1954-03-11
Abstract: 770,106. Gas turbine plant. ROLLS-ROYCE, Ltd. March 1, 1955 [March 11, 1954], No. 7174/54. Class 110 (3). [Also in Group XXIX] An aircraft power plant comprising a plurality of gas turbine engines has each of the engines connected to a high-pressure fuel main which is supplied with fuel by a plurality of air turbine driven pumps of such a capacity that the pressure in the main is maintained in the event of failure of a pump. A plurality of gas turbine lift engines 30, Fig. 2, only half of which are shown, are supplied with fuel from a fuel tank 33 by means of low-pressure pumps 34 and highpressure pumps 39. The low-pressure pumps 34 draw fuel from the tank 33 and discharge it into the low-pressure main 37 through non- return valves 36 and a shut-off cock 38. The high-pressure pumps 39 are separately connected to the low-pressure main 37 and discharge through a control mechanism 44 and high-pressure main 42 to a manifold 49 connected by a series of branches 50 to the engines 30. Each branch contains a shut-off cock 51 and an acceleration control unit 52 so that each engine can be brought into operation independently of the others. The pumps 39 are driven by air turbines 53 supplied with air from a manifold conduit 54 through conduits 55 containing shut-off valves 56. The manifold conduit 54 may be supplied with air either from the manifold conduit 57 or from the manifold conduit 62 through a reducing valve 63. The manifold conduit is supplied with air from the compressors 30a of the lift engines through conduits 60, containing non-return valves 61. The manifold conduit 62 is supplied with air from the compressors of the propulsion engines 31 through a shut-off valve 64 and non-return valve 65. A non-return valve 66 is provided to enable compressed air to be supplied from the lift engines to the conduit 62. To start the lift engines 30 the manifold conduit 62 is connected to a further manifold conduit 67 through a pipe 68 containing a shut-off valve 69. The mani. fold conduit 67 is connected to the turbines 30c of the lift engines through branch pipes 70 containing non-return valves 71. Air may also be supplied to the manifold conduit 62, for starting purposes, from an external source of air such as an air bottle 77. The manifold conduit 57 may be used for supplying compressed air to air jets at the wing tips for control purposes. The fuel supply to the manifold 49 may be controlled by the mechanism 44 in accordance with the atmospheric pressure and temperature and the setting of a control lever 47. The control mechanism may be similar to that shown in Fig. 3, where the fuel supply to the highpressure main 13 is controlled by a throttle valve 25a. The throttle-valve is connected to a servo-piston 25b, one side of which is connected directly to the fuel main 13 and the other side of which is connected to this main through a restriction 25d. A leak-off valve 25e, which controls the pressure on one side of the servo-piston, is carried by a pivoted lever which is loaded at one end by a capsule 25j responsive to the atmospheric or engine intake pressure and a temperature-responsive element 25k responsive to the engine inlet temperature. The lever is loaded at the other end by a spring 25g, the loading of which may be varied by a manual control 25h, and an element 25f responsive to the fuel pressure in the high-pressure main 13. In a modification, Fig. 1 (not shown), the high-pressure fuel main is connected directly to the individual fuel manifold of the engines i.e. the shut-off cocks 51 and control units 52 are omitted.