Enhancing aircraft design: assessing adverse yaw and vertical tail plane reduction using Prandtl wing principles in sailplanes

Abstract

High aspect ratio wings have garnered increasing attention due to their potential to improve aerodynamic efficiency. At the same time, the flight of birds without vertical tail structures has inspired aerodynamicists to explore alternatives to traditional lift distributions. Challenging the elliptical lift distribution could yield minimum-drag configurations while also addressing structural constraints, such as the wing root bending moment. This research examines the effects of Prandtl’s bell-shaped lift distribution on the aerodynamic performance and stability of sailplanes. By modifying the wing configuration of the Slingsby T51 Dart 15, the bell-shaped lift distribution is compared to traditional elliptical and baseline designs. The goal is to assess potential improvements in handling, particularly through proverse yaw behavior, and to evaluate whether the reduction of the vertical tailplane size compromises critical flight performance metrics such as crosswind landing and Dutch roll stability. Findings indicate that this alternative distribution alters aerodynamic behavior, and although reducing the vertical tailplane size does not compromise crosswind landing performance but it raises challenges in Dutch roll stability.