Improvements relating to the starting of gas turbine engines

791,268. Generating combustion products under pressure. GENERAL MOTORS CORPORATION. June 14, 1956, No. 18400/56. Class 51 (1). [Also in Groups XXVI and XXVIII] To start a gas-turbine engine comprising a combustion system connected to a compressor outlet, the engine is provided with an injector for injecting fuel into a part of the combustion system during starting only of the engine and a one-way valve operable automatically during starting only to shut off this part of the combustion system from the compressor outlet. A number of combustion chambers 12, Fig. 1, each consisting of a cylindrical outer casing 22 and a flame tube 24, are arranged around the engine axis. The outer casings 22 are attached by ring clamps 28 to flanges 30 provided around openings in an end plate or bulkhead 32 arranged at the end of the compressor diffuser 14. Fuel injectors 36 supported by mounting pads 38 from the wall of the diffuser 14 project into dome-shaped members 34 forming the inlet ends of the flame tubes. Interconnector pipes 46, Fig. 3, provided between adjacent combustion chambers, comprise a pair of outer tubes 47, 48 and a pair of inner tubes 50, 51. These tubes are provided with flanges 54, 55, 58, 59 which are welded over openings formed in the surface of the outer casings 22 and flame tubes 24, respectively. For starting purposes, one of the combustion chambers, is provided with a one-way valve 62 and a second fuel injector 82 by means of which fuel and an oxidant, such as liquid oxygen, is introduced into the combustion chamber. The valve 62 is formed by inner and outer rings 66, 64 in which are pivoted a number of rods 70 carrying radial flaps 68. The flaps 68 are formed as truncated sector-shaped plates and are welded at one side to the rods 70. The inner ring 66 is polygonal in cross-section and surrounds the nozzle 42 of the fuel injector 36 to which it is attached by a bayonet clip 74. The interconnector pipes 46 adjacent the starting combustion chamber are provided with valves 94, Fig. 3, which are actuated by levers from a rotating electric solenoid. To start the engine, a circuit comprising this solenoid, an igniter 92 and electrical control valves controlling the supply of fuel and oxidant to the fuel injector is energized through a time switch. This causes the valves 94 to close and the fuel from the injector 82 to be ignited. The resulting pressure in the combustion chamber causes the valve 62 to close. The combustion products contain sufficient ene