Effect of Airfoil Profiles on Radar Cross Section of a Cropped Delta Wing

Abstract

The shape and design parameters of a wing have a significant impact on a military aircraft's radar cross-section (RCS). The open literature contains sparse information on the effects of airfoil design parameters of a cropped delta wing on its RCS. When a cropped delta wing faces a H-polarized plane wave, the change in bistatic RCS with various sweep angles was investigated in the first part of this study. To evaluate this change with the sweep angles, a double wedge airfoil was selected and it was swept by four different sweep angles i.e., 35°, 45°, 55°, 65°. A significant variation in the bistatic RCS was observed with sweep angle. In the second part of the study, the wing faced a plane wave with horizontal and vertical polarization and the effect of airfoil shape of cropped delta wing on the monostatic and bistatic RCS was investigated. For this, wings with double wedge, biconvex and NACA 64A010 airfoil profiles were modelled with various sweep angles. when the plane wave was horizontally polarized, the bistatic RCS was insensitive to the airfoil profile. When the polarization changed to the vertical, then significant variation in RCS was observed. The variation in monostatic RCS was also studied in addition to the bistatic RCS, and it was insensitive to the airfoil profile with both polarizations. This investigation was conducted using the Multilevel Fast Multipole Method (MLFMM), a full-wave methodology availabel in the commercial software FEKO.