Patent GB-552157-A (GB)
Title: Improvements in or relating to aerial apparatus
IPC: F42B17/00
Filed: 1941-09-18
Abstract: 552,157. Aerial warfare; ammunition projectile and fuzes therefor. DALINDA, J. Z. Sept. 18, 1941, No. 11997. Convention date, Sept. 18, 1940. [Classes 9 (i) and 9 (ii)] [Also in Group XXXIII] A device adapted to be projected into the air or dropped from an aircraft to support a useful load such as a light-generating mechanism, an acoustic device, or an anti-aircraft entanglement with aerial mine, comprises a helicopter with folding blades driven by an internal combustion engine housed with the useful load in a protective receptacle from which they can be expelled and the engine started. This receptacle may be contained in a shell adapted to be discharged from a gun, the receptacle being expelled from the shell at a desired point of the trajectory by a controllable explosive charge. The helicopter comprises two pairs of blades hinged to hubs 25, 26, the hub being connected to a sleeve 38 rotating upon a fixed spindle 13 and the hub 25 rotating about the sleeve 38. Bevel wheels 40, 44 connected to the sleeve 38 and hub 25 respectively mesh with gears 41, 45 on a shaft 42 which is adapted to be driven by gears 46, 47 from the crankshaft of a single cylinder two-stroke engine 16 supplied from a fuel tank 20. Beneath the tank is a bomb 7 connected to the helicopter by a length of cable 66. The whole of this apparatus is enclosed in a two part receptacle 6, 6A fitting at its ends into grooves in a cover plate 9 and in a flange 10 on the base of the bomb, and this receptacle fits snugly into a shell 1 having a base 2 secured by flangible pins 3. An expelling charge 12 contained in a space 11 above the plate 9 is fired by the usual fuze to eject the apparatus from the shell after which springs 81 on the parts 6, 6A force off the plate 9 and the receptacle falls apart. The blades open out into a horizontal position against stops on their hubs either by spring action, or due to centrifugal force if the shell has been fired from a rifled gun, and a coiled spring 53 starts the engine. The hinges of the blades are set at the desired angle of incidence of the blades with respect to their planes of rotation, or they may so set themselves after the blades have opened. The expelling charge 12 neutralizes the forward motion due to the shell and to compensate for different velocities at different altitudes variable escape holes are provided for the gases generated by the expelling charge 12. To prevent undue jerk on the cable 66 when completely paid out its coils are sealed or soldered together so as to retard the fall of the bomb. A modification is described in which a four stroke engine is used and an incomplete casing comprising four longitudinal strips, replaces the receptacle 6, 6A. The supply to the engine is controlled by a valve 307, Fig. 20, under the influence of a barometric capsule 301 so as to suit the supply of fuel to the altitude it is desired to maintain. The firing and expelling stresses are taken by a central tubular structure 19, the bomb 7 having a similar structure 22 butting against the structure 19. The structure 22 contains the fuze mechanism of the bomb which comprises a striker 201, Fig. 12, normally held in place by balls 203 retained by a sliding sleeve 204 connected to the cable 66. As shown, the sleeve 204 is raised by the cable until radiating cables 212 are taut, in which position the balls 203 are just on the point of escaping. Should an aircraft then hit the cable an enlargement 214 on the cable is forced through a fitting 213, to which the cables 212 are attached, and the striker is completely released. In a modification the sleeve 204 is retained by frangible pins which are only broken to allow the sleeve to be raised when the bomb contacts an aircraft as the cable is drawn over it.