Estimating the Subsonic Aerodynamic Center and Moment Components for Swept Wings

Abstract

An improved method is presented for estimating the subsonic location of the semispan aerodynamic center of a swept wing and the aerodynamic moment components about that aerodynamic center. The method applies to wings with constant linear taper and constant quarter-chord sweep. The results of a computational fluid dynamics study for 236 wings show that the position of the semispan aerodynamic center of a wing depends primarily on aspect ratio, taper ratio, and quarter-chord sweep angle. Wing aspect ratio was varied from 4.0 to 20, taper ratios from 0.25 to 1.0 were investigated, quarter-chord sweep angles were varied from 0 to 50 degrees, and linear geometric washout was varied from − 4.0 to +8.0 degrees. All wings had airfoil sections from the NACA 4-digit airfoil series with camber varied from 0 to 4 percent and thickness ranging from 6 to 18 percent. Within the range of parameters studied, wing camber, thickness, and twist were shown to have no significant effect on the position of the semispan aerodynamic center. The results of this study provide improved resolution of the semispan aerodynamic center and moment components for conceptual design and analysis. b n = twist contribution to the Fourier coefficients in the series solution to the lifting-line equation