Free Flight Tests on Longitudinal Dynamic Derivatives

Free Flight Model FFM-10 is a model which simulates supersonic aircraft with delta wing. The model is propelled by a rocket motor installed in the fuselage. Longitudinal short period motion is excited by two side jets ignited in sequence. Measurements of acceleration in the direction of pitching motion enables to derive longitudinal static and dynamic aerodynamic derivatives. The results are compared with theoretical estimates and shows fairly good agreement. Although much improvement should be pursued to obtain enough accuracy, the preliminary result shows that the technique employed is very promising.