Rocket assisted projectile and cartridge with time delay ignition and sealing arrangement

A cartridge comprising

• a casing having an ignitable propellant therein for propelling a rocket assisted projectile therefrom,
• and a rocket assisted projectile secured within said casing with its rear end adjacent said propellant and contactable by the burning propellant gases resulting from ignition of said propellant,
• said rocket assisted projectile comprising a thin-walled body shell, longitudinally spaced forward and rear penetrator supports within said shell and having aligned coaxial bores formed therein and extending therethrough, a central penetrator mass coaxially supported by and mutually rigidifying said thin-walled body shell by being longitudinally and laterally rigidly secured, both prior to and during projectile flight, in sealed relation within and extending through and axially beyond each of said support bores, said rear support forming a nozzle block having a plurality of discharge nozzles formed therein, said central penetrator mass, thin-walled shell and spaced supports forming a sealed chamber for containment of a rocket propellant therewithin, and end-burning rocket propellant grain disposed within said chamber and having its effective burning end facing said nozzle block, said nozzle block discharge nozzles being plugged in pressure-sealing relation with solid ignitable time delay plug igniters to thereby prevent initial entry of propellant gases at initial high propellant gas pressures into the rocket grain chamber, while enabling ultimate ignition of the rocket propellant by intermediate ignition of said solid ignitable time delay plugs from propellant gases external of the projectile and in contact with said time delay plug igniters, said central penetrator mass forming a multi-function element as a chamber-bounding element for the rocket propellant, a rigidifying element structurally cooperating with and enabling employment of a thin-walled body shell, and as a radial concentrator of mass of maximizing accuracy of flight and maximizing target penetration.

A cartridge comprising

• a casing having an ignitable propellant therein for propelling a rocket assisted projectile therefrom,
• and a rocket assisted projectile secured within said casing with its rear end adjacent said propellant and contactable by the burning propellant gases resulting from ignition of said propellant,
• said rocket assisted projectile comprising a thin-walled body shell, longitudinally spaced forward and rear penetrator supports within said shell and having aligned coaxial bores formed therein and extending therethrough, a central penetrator mass coaxially supported by and mutually rigidifying said thin-walled body shell by being longitudinally and laterally rigidly secured, both prior to and during projectile flight, in sealed relation within and extending through and axially beyond each of said support bores, said rear support forming a nozzle block having a plurality of discharge nozzle formed therein, said central penetrator mass, thin-walled shell and spaced supports forming a sealed chamber for containment of a rocket propellant therewithin, and end-burning rocket propellant grain disposed within said chamber and having its effective burning end facing said nozzle block, said nozzle block discharge nozzles being plugged in pressure-sealing relation with solid ignitable time delay plug igniters to thereby prevent initial entry of propellant gases at initial high propellant gas pressures into the rocket grain chamber, while enabling ultimate ignition of the rocket propellant by intermediate ignition of said solid ignitable time delay plugs from propellant gases enternal of the projectile and in contact with said time delay plug igniters, said central penetrator mass forming a multi-function element as a chamber-bounding element for the rocket propellant, a rigidifying element structurally cooperating with an enabling employment of a thin-walled body shell, and as a radial concentrator of mass for maximizing accuracy of flight and maximizing target penetration said rocket propellant grain being a ring grain having an inhibitor along its radially inner, outer and forward surfaces.