Optimal Thrust Vectoring for an Annular Aerospike Nozzle

Recent success of an annular aerospike flight test by NASA Dryden has prompted keen interest in providing thrust vector capability to the annular aerospike nozzle (AAN). The AAN with a moveable spike could provide a solid-fueled rocket with thrust vectoring and unique throttling capability. Cal Poly, which has a thrust vector research facility, has teamed with Rolling Hills Research Corporation, with CFD capability, to experimentally and analytically determine the optimal approach to thrust vectoring and throttling the AAN. In Phase I a scale model AAN will be fabricated to include a movable spike that can be displaced and/or gimballed. One set of studies with this model will examine thrust changes as a function of spike position. Other studies will examine the thrust vectoring effectiveness of vanes at two positions: side of the spike and outer edge of the annular throat. Nozzle exhaust flows will be photographed using color Schlieren techniques in order to validate CFD analysis. The most promising of the nozzle configurations for thrust vectoring and throttling will be selected from Phase I results. In Phase II, the selected configuration will undergo extensive laboratory testing and computational analysis for optimization. The objective of Phase III will be flight test.