Patent GB-865849-A (GB)
Title: Starting method and apparatus for aircraft equipped with alternators
Inventor: MESPOULHES ROBERT
IPC: F02C7/277
Filed: 1959-03-31
Abstract: 865,849. Gas turbine plant. SOC. NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION. March 31, 1959 [April 9, 1958], No. 10893/59. Class 110(3). An alternator on board an aircraft is started, when the aircraft is on the ground, in conjunction with the starting of the aircraft propulsion unit (which may be a gas turbine jet propulsion engine) by supplying a turbine which drives the alternator with the same fluid as is used for starting the main propulsion unit. In Fig. 1 the parts indicated above the line AA represent equipment mounted on board an aircraft whereas parts indicated below the line represent ground equipment. At starting, air under pressure from the bottle 1 is supplied through duct 3 and branch 8 through the connector 13 to the intake 12 of the air turbine 10 which drives the alternator 11. The duct 3 contains a cock 2 and pressure-reducing valve 7, and the branch 8 contains a further pressure-reducing valve 9. Current flows through line 14 and when the indicator 22 lights up, the switch 18 is closed manually whereby current flows through the coil 15 thereby opening valve 16, also through the ignition circuit of the aircraft jet-propulsion unit. Opening of the valve 16 permits air under pressure in the duct 3 to flow to the starter 5, whereupon the engine starts. After a certain number of revolutions, detected by the counter 20, the contacts 19 open whereupon the valve 16 closes. The cock 2 is then closed and ground equipment disconnected. In Fig. 2, air under pressure from the bottle 1 flows to a nozzle 23 disposed in the intake 12 of the turbine 10 driving the alternator 11, the nozzle 23 and intake duct 12 constituting an injector device. At starting, the switch 37 is closed whereupon current flows from battery 34 through the coil 30 which causes the valve 28 to open whereupon air flows from bottle 1 to the nozzle 23 and the alternator 11 is driven and supplies current to the line 14. The switch 18 is then closed as in the first embodiment causing the starter 5 to operate, the circuit being opened at 19 as before after the engine has 'made a certain number of revolutions. The switch 37 is finally opened manually. In a third embodiment similar to Fig. 1, the duct leading to a nozzle 23 disposed in the intake 12 of the air turbine 10 is rigidly connected to the duct 4 at a point within the aircraft. In Fig. 4, air under pressure from the bottle 1 passes through ducts 3 and 4 to the starter 5, exhaust air therefrom passing through duct 40 to drive the turbine 10 driving the alternator 11. In this case, the electromagnetic valve 43 and also the contact 19 are normally open. Upon opening the valve 2 therefore, air under pressure flows through the starter 5 thereby rotating the main engine, the air then discharging through the turbine 10 to drive the alternator 11. When the indicator 22 lights up, the switch 18 is closed manually and current flows through line 21 to the igniter of the main engine. After a certain number of revolutions of the engine, the contacts 19 close and current flows to the coil 44 which causes the valve 43 to close. The ground equipment is then disconnected. In a further embodiment, combustion gases under pressure are generated by the firing of a cartridge, the apparatus otherwise being similar to that of the third embodiment except that the cartridge chamber and ducts leading therefrom are contained within the aircraft. The cartridge is fired by means of a battery contained therein so that no external ground equipment is necessary. In the event of failure of the main engine when in flight, the turbine 10 may be supplied with air from the slipstream so that the alternator 11 continues to function.