LAYER-SCALE WIND-TUNNEL TESTS OF AN AIRPLANE WITH A 45° SWEPTBACK WING OF ASPECT RATIO 2.8 WITH AREA SUCTION APPLIED TO TRAILING-EDGE FLAPS AND WITH SEVERAL WING LEADING-EDGE MODIFICATIONS

摘要

An investigation of an airplane model was conducted to determine the effect of area-suction trailing-edge flaps and several leading-edge modi¬fications on the aerodynamic characteristics of a 45° sweptback wing. The wing had an aspect ratio of 2.8 and a taper ratio of 0.17. The wing was tested with a small-span constant-chord flap and, to a lesser extent, with a larger span constant-percent wing-chord flap. Area suction was applied to both flaps. Leading-edge flaps and modified leading-edge contours were tested in an effort to produce adequate leading-edge stall control. A chord extension and a fence were also tested. Part of the testing was done with a horizontal tail installed above the extended wing-chord plane. The tests were made at a Reynolds number of 10X106.nThe flap lift increments with area suction applied to the flap were within approximately 90 percent of the theory of NACA Report 1071 at low angles of attack. At high angles, of attack, wing leading-edge modifica¬tions were necessary to maintain the lift effectiveness of the flaps.nIt was found that with the smaller trailing-edge flap, higher maximum lifts were obtained with a deflected plain leading-edge flap extending from the 40-percent semispan station to the wing tip than were obtained with full-span leading-edge flaps. The larger span trailing-edge flaps produced a maximum lift only slightly higher than was obtained with the small trailing-edge flap.