Patent GB-836622-A (GB)
Title: Low altitude bombing system and apparatus
IPC: F41G3/24
Filed: 1957-02-20
Abstract: 836,622. Discharging bombs from aircraft. RYAN, J. A. Feb. 20, 1957, No. 5823/57. Classes 9(1) and 9(2) Apparatus for releasing bombs from aircraft comprises release means operated by an attitude responsive device when the angle of climb of the aircraft reaches a predetermined value, setting means being provided to bring the apparatus into an operative condition. The attitude responsive device is a gyroscope H, which is caged until the setting means is operated. Fixed on an arm 73 carried by the outer gimbal 72 is a wiper 74 which closes the bomb release circuit when it contacts switch blades 66 adjustably mounted on the gyroscope frame 75. To adjust the blades 66 relative to the wiper 74, a shaft 92 is turned to bring the appropriate setting on a dial 81 into register with an index line. Rotation of the shaft 92 drives a pinion 79 and so rotates a sector 76 carrying the overlapping parallel blades 66, each of which is connected by a slip ring in channels 83, 84 respectively of a support 82 to one of a pair of contact bushes and hence to a relay 57 in the bomb release circuit. Adjustably mounted on the support is an index ring 86 with readings which also register with the index line. Before " take-off ", the shaft 92 is rotated with the gyroscope caged, until the selected angle of climb, Fig. 1, (not shown), is shown on the readings, the blades 66 then being in the proper angular relation with the wiper 74 to hold the bomb release circuit open until the angle K, Fig. 1, (not shown), is reached. When the gyroscope is adjusted a signal timer I is set for the calculated time of flight from a landmark to the point where the aircraft begins to climb and a time fuze I<SP>1</SP> in the bomb is set for the time from the landmark to the instant of arrival over the target. On approaching the landmark, a switch 11 is closed to energize a transformer 17 and start the gyroscope motors 18, 19, 19<SP>1</SP>. Closure of switch 11 causes two potentiometers 22, 23 to adjust a pitch and roll indicator 24 to indicate the positions of the inner and outer gimbals relative to the altitude of the aircraft and to indicate the roll and pitch attitude of the aircraft after the gyroscope is uncaged. Next a switch 27 is closed to start the signal timer motor, a signal lamp 31 being provided in the circuit. A switch 32 is also closed to energize a solenoid 34 and so uncage the gyroscope H. The apparatus is then ready for control and indicating operations and as the landmark is crossed a bomb button switch 35 is closed and maintained depressed until the bomb is released. Closure of switch 34 flashes on a warning light 70 to indicate that the timing cycle has begun and also closes a circuit through leads 42, 43 to the signal timer I and to the time fuze I<SP>1</SP>. The timer I after a predetermined interval cuts out the lamp 31 as a signal to the pilot to begin the climb. When the angle of climb K, Fig. 1, (not shown), is reached, the switch 10 closes, energizing the release circuit 59 and flashing on the lamp 31 as an indication to the pilot to execute the prescribed escape manoeuvre. By releasing the switch 35 before the lamp 31 is extinguished, the signal times and bomb time fuze are restored to " zero " position and the timing cycles are restarted. The time fuze I<SP>1</SP>, Fig. 4, comprises an electric detonator 103 to set off the bomb 104. The circuit to the detonator is closed when spring contacts 105, 106 are forced together by a pin 107 projecting from an arm 108 loosely mounted on a shaft 109. The arm 108 carries a toothed gear 110 meshing with a gear 68 and is thrust by a spring 111 towards an adjustable stop 114 pinned to the shaft 109, so that by rotation of a knob 115 the arm 108 can be set to any time interval indicated on a dial 116a. A motor 117 to operate the fuze is energized when the switch 35 is closed. In circuit with the motor is a solenoid 118 of which the armature controls a lever 119 to engage a clutch 120 in the transmission between the motor 117 and the gear 68 and so start the drive of pin 107 towards the contacts 105, 106. If the circuit of a battery 121 is interrupted before the bomb is released, a spring 118a disengages the clutch and the spring 111 resets the time cycle. As the bomb is released, contact strips 124 separating pairs of contact blades 125 are withdrawn, thus breaking the fuze circuit from the aircraft and simultaneously closing the circuit of the battery 121 to the motor 117.