Patent GB-662429-A (GB)
Title: Improvements relating to projectiles
IPC: F42B5/10
Filed: 1944-02-23
Abstract: 662,429. Projectiles. BLACKER, L. V. S. Feb. 23, 1945. [Feb. 23, 1944] No. 3415/44. Class 9 (i). Relates to projectiles intended to be fired from breech or muzzle-loading weapons by the explosion of a primary charge of propellant and containing a combustible or explosive charge e.g. a reaction charge, which must be ignited during the flight ot the projectile, and a secondary charge which is ignited by means driven forwards by the primary explosion and an ignition serves to ignite the reaction or other charge and also to jettison the parts behind it within the tail of the projectile, and consists in the chamber in which the secondary charge explodes being wholly closed except for a small hole at the front through which a small part of the burning gases may pass to ignite the reaction or other charge, the high pressure gases of the primary explosion being completely prevented from entering the secondary explosion chamber and from coming into contact with the reaction or other charge. The Figures show a breech-loaded projectile reaction propelled after receiving an initial velocity by by means of a primary charge of propellant, having an explosive head 1, and a cylindrical part 2 containing the reaction charge 3 ignited by a quick match 4. A casing 5 is provided for streamlining purposes. The reaction gases discharge through a venturi tube 6. At the rear end of the cylindrical part 2 is a cartridge case 8 containing the primary propellant 7 and embracing a thin-walled gas-check 9, the forward face of which is reinforced by a thick plate 10 welded in turn to a tubular member 11, through which some of the gases of the primary explosion may pass to drive forward a member 12 fitting closely in the tubular member 11 and cup-shaped at the rear to act as a gas check in conjunction with the inner surface of the member 11 and shaped forwardly as a firing pin 13 to fire the small secondary charge 15 contained in a cylindrical cartridge case 16 forming the side and rear walls of the secondary explosion chamber. The front of the chamber is formed by a loose diaphragm 17 having a small port 18 and bearing on a thrust ring 19 welded to the inside of the tail. When the secondary charge is ignited the member 16 and parts behind it are ejected from the tail of the projectile and some of the burning gases from the secondary charge pass through the small hole 18 to ignite the quickmatch 4 and hence the reaction charge 3. The loose member 17 is easily ejected by the gases from the burning reaction charge. In the muzzle-loaded projectile described, the construction is similar in principle, but the secondary charge is in two parts, are in the rear wall of the secondary chamber and one in a space formed in rear of the loose member 17 which is considerably thicker than before, the quick match 4 extending down the middle of a comparatively long hole in the member and being in contact with the part of the secondary charge contained therein. Alternatively the construction can be similar to that of the breech loaded projectile, but the primary gas check and associated parts of slightly smaller diameter to allow the entire projectile to pass down the bore of the weapon. The Provisional Specification states the invention is applicable to projectiles having a tracer charge or a charge for ejecting a parachute, in addition to reaction propelled projectiles.