Project Monarch: The application of Ludwig Prandtl's bell-curve span loading to a straight, high performance sailplane wing

Abstract

This thesis focused on the design considerations and application of Ludwig Prandtl's 1933 bell-curve span load to a high performance, straight aircraft wing. Sailplanes are designed to maximize lift-to-drag ratio and reduce induced drag through a combination of planform optimization and airfoil selection to maximize performance. This project took an existing sailplane and redesigned its wing, favoring a bell curve lift distribution instead of the original elliptical lift distribution. The new wing aimed to further reduce induced drag by 11 percent and create proverse yaw while maintaining the same root bending moment as the original wing, to result in a more aerodynamically efficient aircraft of the same weight and structure. Major aerodynamic design choices were determined using Prandtl's Lifting Line Theory, low-fidelity analysis using Avena Vortex Lattice and XFLR5, and high-fidelity Computational Fluid Dynamics results utilizing Oklahoma State University's High Performance Computing Center. Structural design was completed using Solidworks, and the manufacturing and testing of the new aircraft wing will be compared to the existing performance values of the original sailplane wing, to prove the increased performance seen during the design stage.