Flight measurements of the lift, longitudinal trim and drag of the fairey delta 2 at mach numbers up to 1.65 and comparisons with wind-tunnel results

Abstract

Measurements have been made on the Fairey Delta 2,60° delta research aircraft, mainly at 40 000 ft; some tests were made at lower altitudes to study aeroelastic effects. The main points from the results are as follows. The trimmed lift-curve slope is independent of incidence, but the trim curves are non-linear for large elevator deflections. The relationship between the drag coefficient and the square of the lift coefficient is non-linear at subsonic speeds but linear at supersonic speeds. The effect of altitude on the trim and drag results is significant, apparently because of aileron rigged-up angle differences, and Reynolds number effects. Comparison of flight and tunnel resu.lts shows good agreement for the slope of the trim curve, but there are significant differences in elevator angle. These differences are consistant with those found in the trimmed lift data and can not be comple'~ely explained in terms of the different aileron riggid-up angles in flight and tunnel. The lift and pitdfing moment are probably affected by the known difference between the development of the wing vortex in flight and tunnel. Agreement between flight and tunnel values of the elevator pitching power, and trimmed and untrimmed lift-curve slopes is good although that for the pitching power may be fortuitous; that for elevator lifting power is fair. The increase in manoeuvre margin from subsonic to supersonic speed is smaller in flight.