Solid Propellant Thrust Control Using a Movable Nozzle

Thrust management in a SRM-powered missile system allows the missile to successfully engage a wider range of targets, and a given propulsion option to be applicable across a range of missile platforms. Thrust control in a SRM is performed by controlling the choked throat area at the nozzle throat. Previous research has accomplished this by moving a pintle back and forth through a fixed nozzle. CFDRC proposes to reverse this paradigm and explore the movement of the nozzle in relation to a fixed pintle. Issues arising from this approach include sealing against hot gas in more places and potentially large actuation forces. There are engineering approaches such as pressure-balancing, which CFDRC has used with success in other programs that will be applicable here. CFDRC currently has identified three separate concepts for moving the nozzle that are promising. In Phase I, CFDRC will examine each of the three actuation approaches and weigh the cost and performance benefits. The Phase I will end with CFDRC testing at least one concept in a room-temperature actuation rig. In Phase II, the best-performing actuation concept will be developed into a flight-configured motor. CFDRC will team up with a propellant supplier to complete a working motor and it will be test-fired.