High-speed wind-tunnel tests on six wings of 40-deg sweepback, with various section shapes

Abstract

Tests have been made in the Royal Aircraft Establishment High-Speed Wind Tunnel on six wings, all of the same plan form (aspect ratio 3.5, taper ratio 0.4, quarter-chord sweep 40 deg) and thickness/chord ratio (10 per cent) but of different section shapes. Four of the wings had symmetrical sections, one was cambered and one was twisted with camber varying from root to tip. Of the symmetrical wings, the one with RAE 101 section had a much better performance than the other three (RAE 104, NACA 66A-010 and HSA I). The steep drag rise with Mach number occurred at a Mach number about 0.02 higher on the RAE 101 wing than on the next best wing (MD for CL = 0.2 was 0.91). The RAE 101 wing also had a higher lift-curve slope and more regular pitching-moment characteristics. The HSA I wing, which has a large leading-edge radius, appeared to give unsatisfactory pitching moments at a low CL and high Mach number. The wing with constant camber gave disappointing results, but the twisted, cambered wing had a very good performance. Compared with the symmetrical RAE 101 wing, it had higher values of MD and lower values of drag for all values of CL above 0.2. It is thought that, for wings of constant section, and having the plan form and thickness/chord ratio used for these tests, the RAE 101 section is close to the optimum. However it should be possible to obtain further improvements by varying the section shape from the root to the tip.