Flight-Determination of the Low-Lift Drag and Longitudinal Stability of a 1/10-Scale Rocket-Powered Model of the Douglas XF4D-1 Airplane at Mach Numbers from 0.7

A flight investigation has been made to determine the drag and longitudinal stability of a 1/10- scale model of the Douglas XF4D-1 airplane from Mach numbers 0.7 to 1.4 at lift coefficients near zero. The drag rise occurred near M = 0.95. The external drag coefficient was a constant value of about 0.012 at subsonic speeds up to the point of drag rise where it increased abruptly to a value of 0.030 at M = 1.0 followed by a more gradual increase to a value of 0.038 at M = 1.25. The model indicated that, at 35,000 feet and a level-flight free-stream Mach number of 1.0, the drag of the full-scale airplane would exceed the thrust available from an XJ40-WE-8 engine with after-burning. The transonic trim change was small. The aerodynamic center moved gradually from the most forward location of 21.0-percent mean aerodynamic chord at M = 0.9 to the most rearward location of 40-percent mean aerodynamic chord at M = 1.25. The damping in pitch was low.