Load Distribution on Multielement Deformed Airfoils with Gap Effects

Abstract

b Bn Bp c c The aerodynamic loading for deformed wings with elevens in subsonic flow is considered. The solution procedure falls into the potential flow category with appropriate restrictions. Lifting surface Kernel function formulation is used in which the local pressure loading for both wing and elevon is determined simultaneously and written as a summation equation. The solution procedure allows closed-form results to be obtained for the elevon hinge moments. Cases under study include gaps between wing and elevon in addition to arbitrary wing- elevon deformations. Fuselage effects and leading-edge suction are also used to apply results to a general con- figuration. Results for all cases compare very well with experimental data. Experimental data taken in a low- speed wind tunnel are presented for a cropped delta wing and rectangular elevon in which the wing-elevon gap was the primary test variable. Nomenclature aspect ratio wing span wing loading coefficients elevon loading coefficients local wing chord mean aerodynamic chord of the configuration (excluding gap length), reference length root chord of elevon tip chord of elevon section lift section hinge moment coefficient lift coefficient pitching moment coefficient about wing root chord leading edge pressure coefficient (p-px) Iq^ integral of the chordwise term of the pressure loading function, see Eq. (12) lift force on the wing freestream Mach number freestream dynamic pressure wing-elevon planform area (excluding gap area), reference area nondimensional perturbation velocity parallel to z axis Cartesian coordinates angle of attack Mach flow parameter, Vl -M2* elevon angle relative to wing (trailing edge down is positive) gap width between wing trailing edge and elevon leading edge wing leading-edge sweep angle nondimensional spanwise variable nondimensional variables, see Eq. (2) Sijibscripts E = elevon H = hinge characteristics HL = hinge line LE = leading edge nm = points or constants associated with the wing pq = points or constants associated with the elevon T = total TE = trailing edge VLE — leading-edge vortex W = wing 0 = denotes wing coordinate variables oo = freestream conditions