Back to results
US 2003/0079464 A1Published application
Rocket motors with insensitive munitions systems
AssigneeAlliant Techsystems Inc.
InventorsMark A. Solberg, Robert E. Black
Life of this patent
Estimating the term…
Abstract
An embodiment of the rocket motor of this invention employs an insensitive munitions approach that, when subjected to elevated external temperatures, is activated by thermal expansion of the main propellant and gas generation from a secondary insensitive munitions charge. In a preferred embodiment, the rocket motor also includes a pressure equalizing system that accommodates changing temperature conditions during storage as well as varying gas pressure inherent in gun-launched systems in a manner that allows for thinner case cylinder design and increased propellant volume.
Claims27
A rocket motor having insensitive munitions capability, the rocket motor comprising:
- a case including a cylindrical region, a closed forward end, and an aft assembly, the aft assembly comprising an aft closure member provided with an opening, the case being rupturable at an internal pressure burst level;
- a nozzle assembly coupled to the case, the nozzle assembly comprising a nozzle passageway;
- a primary propellant grain contained in the case and having an auto-ignition temperature at which the primary propellant grain auto-ignites, the primary propellant grain formulated to undergo thermal expansion in response to being heated to temperatures below the auto-ignition temperature so as to fill free volume, if any, inside the case and to apply an internal pressure to the case that is less than the internal pressure burst level;
- an igniter assembly operational between an inactive state, in which the nozzle passageway is obstructed, and an activated state, in which the igniter assembly ignites the primary propellant grain and the nozzle passageway is substantially unobstructed to permit flow through the nozzle passageway;
- and
- an insensitive munitions charge located inside the case and having an insensitive munitions auto-ignition temperature at which the insensitive munitions charge auto-ignites to release gas, the insensitive munitions auto-ignition temperature being below the primary propellant auto-ignition temperature, the insensitive munitions charge being present in an effective amount that the gas released by auto-ignition of the insensitive munitions charge combines with the internal pressure applied by the thermal expansion of the primary propellant grain when the igniter assembly is in the inactive state to raise the internal pressure inside the case above the internal pressure burst level for rupturing the case before the primary propellant grain reaches the auto-ignition temperature thereof.
3 more elements
A rocket motor having insensitive munitions capability, the rocket motor comprising:
- a case including a cylindrical region, a closed forward end, and an aft assembly, the aft assembly comprising an aft closure member provided with an opening, the case being rupturable at an internal pressure burst level;
- a nozzle assembly coupled to the case, the nozzle assembly comprising a nozzle passageway and a throat barrier member for obstructing the nozzle passageway;
- a primary propellant grain contained in the case and having an auto-ignition temperature at which the primary propellant grain auto-ignites, the primary propellant grain formulated to undergo thermal expansion in response to being heated to temperatures below the auto-ignition temperature so as to fill free volume, if any, inside the case and to apply an internal pressure to the case that is less than the internal pressure burst level;
- an igniter assembly positioned within the nozzle assembly and operational between an inactive state, in which the igniter assembly is situated the nozzle passageway and the throat barrier member obstructs the nozzle passageway, and an activated state, in which the igniter assembly ignites the primary propellant grain and the nozzle passageway is substantially unobstructed by the throat barrier member to permit flow through the nozzle passageway;
- and
- an insensitive munitions charge located inside the case and having an insensitive munitions auto-ignition temperature at which the insensitive munitions charge auto-ignites to release gas, the insensitive munitions auto-ignition temperature being below the primary propellant auto-ignition temperature, the insensitive munitions charge being present in an effective amount that the gas released by auto-ignition of the insensitive munitions charge combines with the internal pressure applied by the thermal expansion of the primary propellant grain when the igniter assembly is in the inactive state to raise the internal pressure inside the case above the internal pressure burst level for rupturing the case before the primary propellant grain reaches the auto-ignition temperature thereof.
3 more elements
A rocket motor having insensitive munitions capability, the rocket motor comprising:
- a case that is rupturable at an internal pressure burst level and includes a cylindrical region, a closed forward end, and an aft assembly, the aft assembly comprising an aft closure member provided with a central opening;
- a sliding piston slidably retained within the aft assembly and the cylindrical region of the case so as to be movable from an at-rest position (a) forward to a maximum pressure position in which the primary propellant grain is axially compressed to radially expand the primary propellant grain toward the cylindrical region of the case in response to firing of the rocket motor, and (b) aftward in response to expansion of the primary propellant grain caused by elevated external temperatures;
- a nozzle assembly slidably mounted within a central bore of the sliding piston, the nozzle assembly comprising a central nozzle passageway and a throat-barrier member for obstructing the central nozzle passageway;
- a primary propellant grain contained in the case and having an auto-ignition temperature at which the primary propellant grain auto-ignites, the primary propellant grain formulated to undergo thermal expansion in response to being heated to temperatures below the auto-ignition temperature so as to fill free volume, if any, inside the case and to apply an internal pressure to the case that is less than the internal pressure burst level;
- an igniter assembly positioned within the nozzle assembly and operational between an inactive state, in which the igniter assembly is situated in the central nozzle passageway and the throat-barrier member obstructs the central nozzle passageway, and an activated state, in which the igniter assembly ignites the primary propellant grain and the central nozzle passageway is substantially unobstructed by the throat-barrier member to permit flow through the central nozzle passageway;
- and
- an insensitive munitions charge located inside the case and having an insensitive munitions auto-ignition temperature at which the insensitive munitions charge auto-ignites to release gas, the insensitive munitions auto-ignition temperature being below the primary propellant auto-ignition temperature, the insensitive munitions charge being present in an effective amount that the gas released by auto-ignition of the insensitive munitions charge combines with the internal pressure applied by the thermal expansion of the primary propellant grain when the igniter assembly is in the inactive state to raise the internal pressure inside the case above the internal pressure burst level for rupturing the case before the primary propellant grain reaches the auto-ignition temperature thereof.
4 more elements
Dependencies are inferred from the claim text.