A Wind-Tunnel Investigation of an Ultra-Light Wing and Ultra-Light Aircraft

Abstract

A wind-tunnel investigation was undertaken on a scaled down rigid model of both an ultra-light wing and an ultra-light aircraft. The results of the ultra-light wing were compared to an existing computation fluid dynamics (CFD) simulation for validation purposes. The comparisons indicated that the results of the simulation did not agree with those from experimentation; it is most notably observed in the drag coefficient results as they are clearly erroneous and further work is required on developing a validated simulation. The basic performance characteristics along with a longitudinal and lateral static stability analysis were completed. It was observed that the aircraft's drag polar does not conform to a classic parabolic shape commonly used to describe conventional fixed-wing aircraft; the suspended fuselage was found to have a dominant effect on the shape of the drag polar when compared to the wing-only experiments. Furthermore, the aircraft was found to be statically stable in pitch and statically unstable in yaw. The pitch stiffness, c Mα , was determined to be -8.33 rad −1 . The weathercock stability derivative, c N β , was determined to be -0.0274 rad −1 implying directional instability.ii