Experimental Assessment of Vortex Retaining Cavity Flaps for Maneuverability Improvement on Delta Wing Fighter Aircraft

摘要

An experimental study was conducted to determine the effectiveness of cavity flaps on delta wing aircraft maneuverability. Cavity flaps are conformal control surfaces deployed in the apex region on the wing's lower surface. A 60 degree swept delta wing model was built and tested in the Air Force Institute of Technology five-foot diameter, subsonic wind tunnel. Ten different cavity flap configurations were tested at deflection angles ranging from 30 degrees to 90 degrees for both asymmetric and symmetric deployments. Coefficients of aerodynamic forces and moments versus angle of attack along with the lift to drag ratio versus lift coefficient and the drag polar were plotted for each flap configuration. The changes to the aerodynamic coefficients produced by adding the cavity flaps were also plotted. Results indicate that for longitudinal, lateral and directional maneuverability, the best cavity flap deflection angle will vary depending on the desired response. Data results also indicated it is best not to have the cavity flap hinge line located along or parallel to the fuselage for rolling and pitching moment considerations. (Thesis) Keywords: Cavity Flaps, Leading Edge Vortex Flaps, Vortex Flaps, Delta Wing, Vortices, High Alpha, Yaw Control, Vortex Lift Effect, Maneuverability, Hinge Line Sweep.