10-ft x 7-ft tunnel tests up to M = 0.94 of nose droop and a blunt-nosed NACA 3-00 type section on a 7.5 per cent thick 50 deg swept wing

Abstract

This note describes further tests made during 1954 in the Royal Aircraft Establishment 10 ft x 7 ft High Speed Tunnel, as part of a research programme to improve the subsonic longitudinal stability characteristics of a 50 deg swept wing of aspect ratio 3.1 by means such as nose-droop, chord extensions, fences, change of aerofoil section, etc. Lift, drag, pitching-moment and root bending moment were measured with the basic 7½ per cent thick RAE 101 section, with a symmetrical blunt-nosed NACA 3-007.5 section, and with a full-span drooped and thickened nose, at Mach numbers up to 0.94 and Reynolds numbers between 1.7 x 10power6 and 6 x 10power6. The main conclusions are as follows: (i) None of the section changes gives any advantage over the basic RAE 101 section at the highest test Mach numbers. (ii) The drooped-nose sections are superior to the NACA 3-007.5 section at all Mach numbers. (iii) The full-span nose-droop is inferior to the part-span droop with the same section tested earlier in the series. (iv) Better high-speed characteristics should be obtainable by the use of nose-droop without the thickening applied here. Further conclusions are given in Section 5. Oil-film flow patterns show several interesting features which are discussed in some detail. Another feature which is discussed is the occurrence of an unusual adverse scale effect on the drooped wings at low Mach number.