NACA-RM-L55F21

Abstract

<strong>INTRODUCTION</strong> <br>During recent flight tests of a swept-wing fighter airplane (ref. 1), extremely violent, uncontrolled longitudinal and lateral motions occurred at a Mach number of about 0.7 and an altitude of about 30,000 feet in rudder-fixed left aileron rolls. In these rolls, initiated by the application of two-thirds or more of the total aileron deflection, very large negative angles of attack and left sideslip were attained which resulted in high load factors. <br>In the Langley stability tunnel it is possible to obtain the rolling and yawing derivatives of models at combined angles of attack and side-slip. Thus, in order to provide information relative to the uncontrolled motions of the fighter airplane of reference 1, an investigation was made and with a vertical tail that had an exposed area which was abuts 27 percent larger. The purpose of this investigation was to determine. The rolling derivatives and the effect of aileron deflection on this derivative for various angles of attack and sideslip. In addition, the static longitudinal and lateral characteristics (ailerons undeflected and deflected) were determined. The yawing derivatives were also determined with the ailerons undeflected and deflected for various angles of attack and sideslip. The pitching derivatives were obtained at various angles of attack at zero angle of sideslip with the ailerons undeflected and deflected. In order to expedite publication, no expensive analysis of the data has been made.