Patent GB-577903-A (GB)
Title: Improvements in or relating to projectiles and to a method of firing the same
IPC: F42B10/06
Filed: 1943-03-29
Abstract: 577,903. Projectiles. SCHULMAN, J. H. March 29, 1943, No. 5065. [Class 9 (i)] Projectiles having a length to calibre ratio of approximately 4: 1 are of cylindrical form without fins or driving bands, and have a flat nose, the projectile being so designed that its centre of gravity lies between 0.8 and 1.6 calibres from the extreme front edge of the nose, whereby, it is stated, the centre of pressure of the turbulence sheath surrounding the projectile when in flight lies behind the centre of gravity of the projectile and the flight of the projectile is stabilised. The projectile is fired from a smooth-bore gun of slightly larger calibre, or may be fired from a rifled barrel, in which case the rifling provides the clearance space to reduce the peak pressure on the projectile, the projectile having no rotation imparted to it by discharge. A three-inch shell comprises a thin-walled cylinder la, Fig. 1, of synthetic resin or of fibrous material, e.g. paper impregnated with synthetic resin, and coupled by a screwed diaphragm 4 to a similar rear extension 1b which houses the propellant charge (not shown) in bags &c. located round a perforated tube 5 carried by the diaphragm and accommodating a primer, e.g. a standard .303 cartridge. The rear end of the projectile is left open but may be closed for transport by a slip-over cap. The metal nose 2 is flat ended with a lip 3 at its forward end and may have a standard impact fuze. In a modification, the rear end of the body is closed by a plug 13, Fig. 2, of moulded synthetic resin which accommodates the propellant bags 17 and the screwed perforated tube 15 for the primer. The body of the projectile contains the offensive charge, e.g. a bursting charge, smoke-generating composition or a liquid. A smoke-generating projectile for firing from standard rifled guns, e.g. 3-inch guns, may consist of a steel tube 21, Fig. 4, closed at its rear end by a dished diaphragm 24 which is coupled to the body by weak shearing pins 26 and has welded thereon a rear extension tube 27 of smaller diameter than the body 21. The' projectile is crimped into a standard cartridge case 20, Fig. 3. The body 21 accommodates two 25-pound standard smoke canisters 29, and is closed at its forward end by an impact fuze 22. If the projectile is to be fired at supersonic muzzle velocities, a small heavy flat nose may be screwed in front of the fuze 22 to correct instability. A highvelocity, long - range impact - bursting high - explosive mortar shell may consist of a thickwalled cylindrical metal casing 30, Fig. 5, slightly rounded at the edge 32 of the flat nose 31, and having secured to its rear end a streamlined extension 35 terminating in a perforated cartridge holder 36 surrounded by cylinders 37 of propellant secured by wires 38. A cylindrical tail 40 of the same diameter as the body is welded or pinned thereto at 43, and has openings 41 totalling two-thirds of the perimeter for air-flow to compensate the instability in flight resulting from the rounded edge 32. The body has an impact fuze at its forward end.