Wind tunnel testing of an S809 spoiler flap model

Abstract

An 18-inch chord model of the NREL S809 airfoil section with a spoiler flap was tested under 2D steady state conditions in The Ohio State University Aeronautical and Astronautical Research Laboratory 7x10 Subsonic Wind Tunnel. The objective of these tests was to document section lift, drag, and pitching moment characteristics over a wide range of flap deflections and angles of attack. The model was tested under both clean and leading edge grit roughness (LEGR) conditions. The LEGR was used to simulate the accumulation of insects and debris on the leading edge of the rotor blades found in the field. The configuration exhibited a clean maximum lift coefficient of 1.12. The application of LEGR reduced the maximum lift coefficient and increased the drag for low angles of attack and low flap deflections. The LEGR was found to have a negligible effect at high angles of attack (above 20 deg) and high aileron deflection (above 45 deg). At high aileron deflections (greater than 30 deg), the suction coefficient was negative in the region of -6to 30-deg angle of attack. (Author)