AIRFOIL SHAPING FOR REDUCED RADAR CROSS-SECTION

Field methods based on finite difference approximations of the time-do main Maxwell's equations and the potential-flow equation have been dev eloped to evaluate the electromagnetic scattering and aerodynamic char acteristics of airfoils. Strong similarities in the two analysis metho ds facilitate a synergistic approach to solve the multidisciplinary pr oblem of airfoil shaping for aerodynamic efficiency and low radar cros s section (RCS). Results for standard test cases demonstrate that both methods are quite accurate. A parametric study shows that for frontal radar illumination, the RCS of an airfoil is independent of the chord wise location of maximum thickness, but depends strongly on the maximu m thickness, leading-edge radius, and leading-edge shape. In addition, the study shows that the RCS of an airfoil can be reduced without sig nificant effects on its transonic aerodynamic efficiency by reducing t he leading-edge radius and/or modifying the shape of the leading edge.