Patent GB-656333-A (GB)
Title: Improvements in or relating to rocket type propulsion apparatus
IPC: F02K9/56
Filed: 1949-01-03
Abstract: 656,333. Jet propulsion plant. DE HAVILLAND ENGINE CO., Ltd. HALFORD, F. B., CLEAVER, A. V., and DOVE, E. B. Jan. 3, 1949, No. 76. [Class 110(iii)] [Also in Group-XXIX] A rocket propulsion unit of the type in which a propellant liquid or liquids are injected into a reaction chamber where gases are evolved which issue from a propulsive nozzle has a starting control which when actuated causes the propellant liquid or liquids to be injected into the reaction chamber and a thrust selector which if set ir the full thrust position when starting control is actuated allows the propellant liquid or liquids to be injected into the reaction chamber at the full rate but if set in a check thrust position only allows the injection of these liquids into the reaction chamber, at a much reduced rate. The invention is described with reference to the rocket unit described in Specification 656,331. In this unit, compressed air from storage bottles is used to force the propellant liquids from their reservoirs into the reaction chamber. This compressed air passes through a starting valve and a check thrust valve the control and operation of which forms the subject of the present invention. The starting control consists of a switch 50, Fig. 3, which energizes a starting valve actuating solenoid 49 and the thrust selector switch 51. The switch 51 has three positions, an " off " position 52, a " check " position 53 and a " fire " or full thrust position 54. When the switch is in the " off " position, the circuits through both the solenoids 32, 49 are open so that neither is energized when the switch 50 is closed. When the switch is in the " check position both the solenoids 32 and 49 are energized and when in the " fire position only the solenoid 49 is energized. The solenoid 32 controls the check thrust valve 16, Fig. 2, which consists of two valve members namely, a main valve member 24 which when open, allows compressed air to pass freely from the inlet port 25 to the outlet port 26 and a pilot valve 27 which controls the movement of the main valve 24. The valve housing 28 is divided into three chambers 31, 33, and 36 by dividing walls 29 and 30 and has a tubular element 37 which accommodates the pilot valve 27 and acts as a guide, for the main valve 24. When the solenoid 32 is de-energized, a spring 47 urges the valve 27 on to its lower seat 42 and then vents the chamber 33 to atmosphere through the ports 43, 41, and 44. The pressure of the compressed air in the chamber 36 then forces the valve 24 into the fully open position. If the solenoid 32 is then energized, the pilot valve 27 is lifted against the action of the spring 47 on to its upper seat 41. This allows compressed air from the chamber 36 to enter the chamber 33 and act on the piston 34 causing the valve 24 to close. In this position, the compressed air can only reach the outlet port 26 through the restricted passage 40 which causes it to have a considerable pressure drop and results in a considerable reduction of flow of propellant from the reservoirs. An alternative circuit in which the solenoids 32 and 49 are arranged in series is also described. It is also stated that the check thrust valve may be operated by mechanical, hydraulic, or pneumatic means. The propellant may be hydrogen peroxide, which is mixed with a dissociation catalyst such as sodium 'of calcium permanganates. Specification 656,332, [Group XXIX], also is referred to.