Wind-Tunnel Tests at Low Speed of Swept and Yawed Wings Having Various Plan Forms

摘要

Wind tunnel tests of an exploratory nature have been made at low speed of various small-scale models of sweptback, sweptforward, and yawed wings. The tests covered changes in aspect ratio, taper ratio, and tip shape. Some data were obtained with high-lift devices on sweptback wings and with ailerons on sweptforward wings. The data have been briefly analyzed and some comparisons have been made with the available theory. The results of the tests and the analyses indicated that the values of lift-curve slope and effective dihedral of swept wings can be computed with a reasonable degree of accuracy in the low- lift- coefficient range by means of existing theories. In general, reducing the aspect ratio and the ratio of root chord to tip chord resulted in increases in drag and effective dihedral and increased the longitudinal stability near the stall. Cutting off the tip of a sweptback wing normal to the leading edge reduced the effective dihedral at low lift coefficients and gave a slight reduction in the drag at high lift coefficients. Sweeping forward a part of the outer panel of a sweptback wing improved the longitudinal stability and decreased the effective dihedral but also slightly decreased the maximum lift coefficient and increased the drag at high lift coefficients. The use of high- lift devices at either the leading edge or the trailing edge of sweptback wings increased the lift-drag ratio and the effective dihedral at high lift coefficients. An increase in the ratio of root chord to tip chord for sweptforward wings resulted in decreases in aileron rolling-moment effectiveness that were greater than the values computed for unswept wings.