Experimental Aerodynamic Assessment and Evaluation of an Agile Highly Swept Aircraft Configuration

Abstract

Extensive experimental and numerical investigations on a highly swept generic unmanned combat aerial vehicle (UCAV) configuration of lambda type with a variable leading edge contour have been conducted. Within these investigations it was shown that the flow field is dominated by complex vortex systems including vortex-to-vortex and vortex-to-boundary layer interactions. The vortex dominated flow field has a strong nonlinear influence on the aerodynamic behavior of the configuration. Hence, the controllability aspect is demanding and poses a real challenge in the design of this kind of configuration. Especially the dimensioning of the control surfaces for the lateral- and longitudinal stability aspects of tailless configurations of low aspect ratio and high leading edge sweep poses a challenging task, which is not yet solved. The present paper reviews the experimental aspects of the investigations. In order to understand the problem of lacking lateral- and longitudinal stability for these kind of configuration, experiments in the subsonic and transonic flow regime have been conducted for the SACCON configuration, which has a leading edge sweep of 53° in order to assess the control surface effectiveness of conventional trailing edge control devices. These investigations were undertaken as part of the internal DLR projects FaUSST and Mephisto.