Patent GB-1424173-A (GB)
Title: Ignition system for rocket propulsion unit combustion chambers
IPC: F02K9/95
Filed: 1974-01-08
Abstract: 1424173 Rocket propulsion units - ignition systems MESSERSCHMITT-BOLKOW-BLOHM GmbH 8 Jan 1974 [10 Jan 1973] 00880/74 Headings F1J and F1L The invention relates to an ignition system for a liquid fuel rocket engine in which an ignition fluid in gaseous form is stored in a container, its pressure being increased at starting whereby it may be discharged into the combustion chamber where it reacts spontaneously with one of the propellants, the ignition fluid in the container being sufficient for one ignition cycle; the increase in pressure of the stored ignition fluid is produced by means of the second propellant which does not react with the ignition fluid. The rocket engine shown in Fig. 1 comprises a combustion chamber and thrust nozzle assembly 9, a container 13 of liquid oxygen, a container 14 of liquid hydrogen, and a container 4 of ignition fluid such as fluorine gas. The container 4 comprises a piston 2 which at starting is pressurized by liquid oxygen from container 13 which passes through duct 12 to the upper side of  piston 2 upon opening of valve 11. When the valve 6 in discharge line 7 is opened, the fluorine discharges from the container 4 to the injection head 8 of the rocket, thence through orifices 10 into the combustion chamber. At the same time the valve in the discharge line 15 from the hydrogen container 14 is opened so that hydrogen passes to the injection head 8, thence through orifices 16 into the combustion chamber, the hydrogen and fluorine reacting spontaneously. As the piston 2 approaches the lower wall of the container 4 and the fluorine is wholly discharged, an orifice in the wall of the container is opened by movement of the piston so that oxygen now passes through line 17 controlled by a non-return valve 18 to the discharge line 7, the  oxygen now reacting with the hydrogen discharging through the orifices 16. The fluorine container 4 is re-charged through line 20. The rocket engine shown in Fig. 2 comprises a pre-combustion chamber 22 of annular form, gases passing from the chamber 22 to the main combustion chamber 23 acting to drive the turbine 26 which drives a liquid oxygen pump 28 and'a liquid hydrogen pump 29. The engine comprises also a container 37 for fluorine which may be pressurized by means of gaseous oxygen from container 32 when valve 34 is opened, the oxygen acting against the piston 38 of the container 37. When the valve 43 is opened the fluorine is discharged through line 40 and  injection orifices 42 into the pre-combustion chamber 22. At the same time, gaseous hydrogen from a container 51 passes through line 53 and injection orifices 52 into the pre-combustion chamber where it reacts with the fluorine, the resulting gases passing to the main combustion chamber, whereby the turbine 26 and pumps 28, 29 are driven. As the piston 38 reaches the bottom of the cylinder, ports in the side-wall are opened  whereby oxygen gas from container 32 flows through the ducts 45a, 45b thence through line 40 and injection orifices 42 into the pre-combustion chamber, the oxygen reacting with the hydrogen discharging through orifices 52. Upon opening of the valves 49, 59 liquid oxygen from the pump 28 passes to the injection orifices 42 into the precombustion chamber, and liquid hydrogen passes through nozzle and chamber cooling ducts 57 to discharge into the main combustion chamber through orifices in the turbine outlet guide vane assembly 27. In a similar embodiment the oxygen container 32 is dispensed with, the fluorine container being pressurized by liquid oxygen delivered by the pump (78). Gaseous hydrogen from a container (82) discharging from the pre-combustion chamber acts to drive the turbine and so the pumps (78), (79) at starting.