Low Cost Reliable Dual Diameter Throat (DDT) for Multiple Mission Missiles

Multiple mission missile architectures typically use a two-pulse rocket motor with inter-pulse coast capability. The technology currently used to accomplish this is a two pulse barrier motor with a single axial nozzle that delivers both the first and second pulse impulse. To optimize impulse performance it is desirable to have a two position axial nozzle throat that maintains its geometry during the first pulse and reduces the throat area for the second pulse. Valley Tech Systems has designed a simple, passively activated, easily producible single piece throat insert called the Dual Diameter Throat (DDT)to perform this task. The DDT is a simple passive component that increases the second pulse packaged impulse while minimizing recurring cost as compared with other two position throat concepts. Our Phase I program will study various DDT candidate configurations as applied to a selected advanced multiple missile propulsion system architecture. Requirements will be generated that meet the transient ballistic requirements of both rocket motor pulses. A combination of mechanical design, thermal and structural analyses will be accomplished to assist in this evaluation. A recommended DDT concept will be selected with a more detailed conceptual design accomplished. In addition subscale testing of key technology will be accomplished during the phase I program to demonstrate the feasibility of the DDT technology.