THE EFFECT OF BOUNDARY-LAYER CONTROL BY SUCTION AND OF SEVERAL HIGH-LIFT DEVICES ON THE AERODYNAMIC CHARACTERISTICS IN YAW OF A 47.5° SWEPTBACK WING-FUSELAGE COMBINATION

摘要

The effect of boundary-layer control by suction on the aerodynamic characteristics in yaw of a 47 .5° sweptback wing-fuselage combination with high-lift devices and on the effectiveness of a split-flap-type aileron has been investigated in the Langley full-scale tunnel. The wing section normal to the quarter-chord line was NACA 641-A112, the aspectnratio was 3.5, and the taper ratio was 0.5. The configurations tested included the plain wing and the wing with semispan split and extensible leading-edge flaps. The investigation was made at a Reynolds number of 4.2 x 10° corresponding to a Mach number of approximately 0.07.nThe maximum effective dihedral of the plain wing with and without boundary-layer control was about 0.0031 at approximately 84 percent of the maximum lift coefficient. The installation of the semispan split flaps increased the maximum effective dihedral to 0.0037 as a result of the increase in lift but did not change the characteristic curve as obtained for the plain wing. Boundary-layer control increased the maximum effective dihedral to 0.0042. The extensible leading-edge flaps alone or in combination with the split flaps resulted in a linear varia¬tion of effective dihedral with lift coefficient and a rapid increase in the dihedral effect near maximum lift. Boundary-layer control produced an additional increase in effective dihedral and resulted in a maximum effective dihedral of O.OO63 near the maximum lift.