Deflectable airspike system for use as a flight control mechanism on a supersonic projectile

An investigation into the feasibility of deflecting an airspike to generate a pitching moment to control a 0.40 caliber supersonic projectile is presented. An aerodynamic analysis was used to estimate the pitch control as a function of airspike deflection. The airspike deflections were generated by flexure of a piezoelectric actuator attached to a pivot. The performance of the actuator at various electrical fields was estimated using classical laminated plate theory (CLPT). Finite element modeling was used to capture the dynamic effects and stress concentrations at critical, failure prone areas of the actuator assembly during launch at setback accelerations of up to 100,000 g's. The capability of the system was proven in supersonic wind tunnel tests through Mach 2.5 using a full scale model which demonstrated +/-2° piezoelectrically generated airspike deflections statically, quasi-statically and dynamically through the corner frequency of 23 Hz. Wind tunnel tests verified the generation of pitch control at Mach numbers of 2 and 2.5 with static and dynamic airspike deflections. By using the wind tunnel generated control authority estimations, round intercept performance at extended ranges under various guidance techniques was determined. A full system concept cost analysis of parts and capital was made.