Pressure plotting and balance measurements in the high speed wind tunnel on a half-model of a 90-deg-apex delta wing with fuselage

Abstract

Tests were made at a Reynolds number of 1.8 x 10power6 and Mach numbers up to 0.93. The wing tip was cropped to a taper of 1/7 and the wing section was RAE 102, symmetrical, 10 per cent thickness/chord at 35 per cent chord. Form drag is highly localised near the root at low speed. Above M = 0.88, rearward movement of the strong shock causes a rapid rise of drag at all sections. Spanwise loading at low incidence is close to potential theory for wing without body up to M = 0.9. A tip stall occurs at M > 0.9 for α = 3.65 deg and at M > 0.8 for α= 7.7 deg, and causes a nose-down moment. Overall lift slope at low CL's increases to a maximum at about M = 0.89, then falls off with signs of a recovery at M = 0.92. Local aerodynamic centres at low CL agree with potential theory for wing alone at low speeds, but move backwards beyond M = 0.8. The overall aerodynamic centre for the wing moves back about 10 per cent mean chord by M = 0.92. There is a loss of elevon power for angles up to - 5 deg above M = 0.92, as found on a complete model at lower Reynolds number.