FLIGHT MEASUREMENTS OF THE STABILITY, CONTROL, AND STALLING CHARACTERISTICS OF AN AIRPLANE HAVING A 35° SWEPTBACK WING WITHOUT SLOTS AND WITH 80-PERCENT-SPAN SLOTS AND A COMPARISON, WITH WIND-TUNNEL DATA

摘要

The directional stability of the airplane as measured in steady sideslips by the variation of rudder angle with sideslip angle vas positive with or without slots and with the flaps up or down at all test speeds. A decrease in directional stability occurred with decrease in speed. A part of the decrease in stability with speed was due to the unstable yawing moments caused "by the large aileron deflections required for trim in steady sideslips at low speed. Emoting the ventral—fin extension reduced the directional stability with the greatest reduction occurring at high normal—force coefficients or low speed. The pilot considered the airplane more difficult to fly with the reduced directional stability because in maneuvers inadvertent sideslipping occurred more easily and the sideslip angles reached were higher. At low speed where the dihedral effect was high, large lateral trim changes accompanied the changes in sideslip.