Improved Methodology for Axial Force Prediction at Angle of Attack

Abstract

Animproved semiempiricalmethod foraxialforcecalculation on missilecone gurationshasbeen developed. The methodusesthetheoreticalmethodscurrentlyusedintheU.S.NavalSurfaceWarfareCenter’ saeropredictioncode for zero angle-of-attack axial force computations and several wind-tunnel databases to compute changes in axial force at angle of attack. The method is applicable to bodies alone, wing‐ body, and wing‐ body‐ tail cone gurations for both zero and nonzero control dee ections. It has been developed to allow computation for angle of attack up to 90 deg at Mach numbers up to 20. However, it has been validated against data only to Mach number of 4.6 and angle of attack to 40 deg for all cone gurations. For body alone and wing‐ body cases, it has been validated to 90 deg angle of attack. Additional test data or Navier‐ Stokes computations would allow ree nement of the improved method. The new method has been compared with several existing techniques. The method was found to be as good as or better than existing techniques but more general than existing methods in terms of cone gurations and Mach numbers allowed for the method to be used.