Patent GB-683484-A (GB)
Title: Ammunition projectile
IPC: F42B12/12
Filed: 1950-02-10
Abstract: 683,484. Self-propelled missiles. SOC. NOUVELLE DES ETABLISSEMENTS BRANDT. Feb. 10, 1950 [Feb. 15, 1949], No. 3499/50. Classes 9(i) and 9(ii), A spin-stabilized projectile with at least one part so arranged that it does not partake o f t h e rotary motion has a casing having an inertia such that the product of the inertia and the speed of rotation is sufficient to stabilize the projectile, while the non-rotary part is mounted freely in the casing and bears against the casing through a rear pivot. Fig. 1 shows a projectile for use against armour plate and the like having a casing 1 divided into two compartments by a web 2. The forward compartment 3 houses a hollow charge in a frusto - conical container 5 closed by a cap 6, a liner 8 fitting the cavity in the charge. The container 8 bears against the web 2 through a pivot comprising two .bearing blocks 10, 11 mounted respectively in the container 5 and the web 2. The blocks are of tungsten carbide or other hard material and are brazed in mountings 12, 13 respectively of mild steel or other material of sufficient plasticity to protect the blocks from shock. The container 5 is centred by ball-bearings, the. front bearing comprising balls 14 housed between bearing surfaces 15, 17. The balls 14 also bear against a cylindrical surface 18 of the container and a coaxial surface 19 of the casing. In the rear guidebearing, balls 20 are housed in a cup 21 projecting from the web 2. By a suitable choice of diameters for the balls 14, 20, the tendency of the hollow charge to rotate in the opposite direction to the casing may exactly compensate the tendency to direct rotation due to friction of the ball-bearings and the abutment pivot. The projectiles may be fired from a rifled gun, the casing then being provided with a driving band 57 and the rear compartment containing an explosive, incendiary, smoke-producing or propellent charge. Alternatively the projectile may be fired as a rocket, the rotation being produced by suitably inclined nozzles. In Fig. 1 the rear compartment contains a propellent charge comprising coaxial cylindrical sticks of powder 24, 25, 26, 27 supported between a shoulder 28 of the casing and a nozzle-carrying member 29 by gratings 33, 35. The outermost cylinder 24 is slit along its length to facilitate insertion in the casing. A coating 32 of thermoplastic resin adhering to the metal and powder may be interposed between the cylinder 24 and the casing 1. The gratings 33 and 35 have projections engaging between the cylinders 25, 26, 27. The grating 33 bears through a ball 37 against the web 2, the cup seating for the ball being surrounded by a baffle 38a stuffed with grease. The rear grating houses a ball 39 bearing against an adjusting screw 42 and a baffle 43a surrounding the ball seating is stuffed with grease. Heat insulating material may be applied to the surfaces of the cylinders contacting the projections 36. The nozzles 45 are fitted into openings in the member 29 with their longitudinal axes Y-Y so inclined that as the propellent gases emerge they cause the projectile to rotate. An axial nozzle 47 is closed by a disc 48 of Cu or Al, which is blown out when the pressure exceeds a maximum value. A safety spider 49 prevents the complete ejection of the disc. An electric primer 60 is embedded in a pellet 61 of black powder housed between the web 2 and the forward grating 33. When the primer is fired by means of lead wires (not shown) passing between the propellent sticks and out through a nozzle,. the propellant is ignited by the pellet 61. As the propellant burns; the grease protects the balls 37, 39 from the flames while the cylinder 24 burns only on its inner surface. The total gas pressure may be controlled by using a highly exothermicpropellant and easily eroded nozzles, e.g. low-carbon steel or by so shaping the propellant that the combustion surface decreases as a function of time. The nozzles may be formed in the end closure of the casing 1. The hollow charge may be replaced by a self-guiding device or by lifting surfaces. The hollow charge may be given an initial rotation in the opposite sense from that of the casing 1.