NACA-RM-L57E02

Abstract

INTRODUCTION <br>Numerous experiments have been made to determine the supersonic aerodynamic characteristics of low-aspect-ratio delta wings at low and moderate angles of attack (for example, refs. 1 to 5). Relatively few tests have been made, however, at high angles of attack (above an angle of attack of 30&#176;) and these data are limited to a maximum Mach number of 3.36 (refs. 6 to 8 and unpublished-data obtained at the Ames Aeronautical Laboratory). This shortage of high-angle supersonic data leaves the designer with no empirical results upon which to base his predictions of the maxim lift and other wing characteristics at high angles. It also precludes a comparison of theoretical methods with experimental results to determine which theoretical methods best predict the high-angle-of-attack and high Mach number wing characteristics. <br>The present investigation, instigated by the lack of experimental data, was conducted on two low-aspect-ratio (1.33 and 2.31) double-wedge-section delta wings in the Langley 9- by g-inch Mach number 4 blowdown jet. In this investigation, normal force, chord force, pitching moment, and wing-root bending moment were obtained for angles of attack from -4&#176; to 50&#176; at a Mach number of 4.07 and Reynolds numbers of 5.3 X 10⁶ and 6.0 X 10⁶ based on the wing mean aerodynamic chords. <br>The experimental results were compared with the predictions of linear theory, two-dimensional shock-expansion theory, Newtonian-impact theory, and a method by Dorrance (ref. 9) wherein the shock-wave and expansion-wave equations are expanded by the two-dimensional hypersonic flow similarity parameter.