NASA-TN-D-3438

Abstract

Results are presented of a wind-tunnel investigation of the static longitudinal stability and control capabilities of a twin-propeller deflected-slipstream STOL airplane in the take-off and landing speed range through the post-stall region at angles of attack up to 44&#176;. <br>The results of this investigation show that the magnitudes of the pitching moments of the wing-body combination for the flaps-retracted (0&#176; flap deflection) configuration were small. The tail-on data show that any of the tail configurations with the flaps-retracted configuration provide an adequate stability contribution and are capable of trimming the airplane. The wing-body combination for the flaps-deflected (45&#176; flap deflection) configuration had a large tail lift requirement for longitudinal trim, particularly for the highest power setting of the investigation. The small tail in the high position had the capability of trimming the airplane for the low power conditions (thrust coefficients of 0 and 0.70). At higher power conditions the tail stalled before trim was achieved. The large tail in either position had the capability of trimming the airplane up to the angle of attack corresponding to the maximum lift coefficient for all but the highest power condition (thrust coefficient of 2.42). This tail stalled before trim was achieved for the highest power condition.