NASA-TN-D-7455

Abstract

A maximum likelihood extraction method has been used to extract the lateral static and dynamic aerodynamic parameters of the Kestrel aircraft from flight test data. The aircraft configurations included thrust-jet angles of 0⁰, 15⁰, and 30⁰, and the test Mach numbers were 0.43, 0.62, and 0.82. The results showed that most of the parameters varied linearly with trim normal-force coefficient. The directional stability parameter C_nβ showed a small increase with increasing trim normal-force coefficient and also with nozzle deflection. The effective-dihedral parameter C_lβ, the damping-in-roll parameter C_lp, and damping-in-yaw parameter C_nr all increased (became more negative) with increasing trim normal-force coefficient. For the latter three parameters, the effect of nozzle deflection was dependent on the trim normal-force coefficient.