Further Studies on the 21% Thick, Supercritical NLF Airfoil NAE (National Aeronautical Establishment) 68-060-21:1.
NATIONAL AERONAUTICAL ESTABLISHMENT OTTAWA (ONTARIO)
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Further wind tunnel tests have been carried out on the NAE 10 in. chord supercritical NLF airfoil NAE 68-060-211. In previous tests, this airfoil showed very low drag levels when free transition was allowed on the model. In the main part of about 7,9 and 13 million, transition was fixed at 7 and 15 on upper and lower surfaces respectively. It is observed that there is a substantial loss of lift under these conditions which appears to be associated with boundary layer thickening on the lower surface causing decambering near the trailing edge. Additional tests were also carried out under free transition at other Reynolds numbers than those previously used. The same drag bucket behaviour near the design flow conditions was observed. Keywords Supersonic airfoils Aerodynamic drag.