VERIFICATION OF THE SM701 AIRFOIL AERODYNAMIC CHARACTERISTICS UTILIZING THEORETICAL TECHNIQUES

Abstract

Utilizing a state of the art low speed airfoil design/aralysis methodology, the Airfoil Program System (APS)the SM701 laminar flow airfoil was designed specifically for the World Class sailplane by Airfoils, Incorporated. The airfoil was expected to exhibit certain design criteria as predicted by the computational methodology, e.g. docile stall characteristics, high maximum lift with low profile drag and restrained pitching moment. Verification of these characteristics was performed by testing a two-dimensional SM701 airfoil in the Texas A & M University Low Speed Wind Tururel (TAMU-LSWT) and comparing the theoretical predictions with the experimental results. Comparisons of the results were done implementing graphical output. Further limited comparisons were done with respect to transition location on the airfoil, utilizing flow visualization techniques in the wind tunnel. These transition locations are predicted in the airfoil analysis methodology utilized in this study. The problem of airfoil roughness is also addressed by the APS. While roughness in the formof grit was not added to the wind tunnel model, predicted theoretical roughness values were included in the test comparisons.