An Investigation on Eppler 387 and Selig 1223 Airfoils Integrated Wing Section for Solar-Powered Unmanned Aerial Vehicle

This study examines the aerodynamic performance of a wing section incorporating high-lift airfoils for use in a solar-powered Unmanned Aerial Vehicle (UAV) operating at low speeds. This paper evaluates the aerodynamic performance of a wing section integrated with high-lift airfoils for application in a solar-powered UAV. The primary objective is to simulate low-speed flight conditions representative of solar-powered UAV missions in order to obtain relevant aerodynamic parameters by adopting Eppler 387 and Selig 1223 airfoils. Experimental and Numerical simulations are performed over a range of angles of attack to systematically assess key aerodynamic coefficients, including the coefficient of lift (C_l), coefficient of drag (C_d), and coefficient of pressure (C_p) to sustain the flight physics and steady level flight. A scaled prototype of the wing section is experimentally evaluated in a low-subsonic wind tunnel to validate the computational results under low-speed operating conditions. An insightful study on the distribution of static and dynamic pressure over the wing surface is analyzed using computational fluid dynamics (CFD) techniques to quantify aerodynamic performance. The Eppler 387-Selig 1223 twin-airfoil wing section attained the coefficient of lift C_l = 1.89 at 13° angle of attack (α), and it is suggested to utilize it for commercial solar-powered UAVs at low-speed operating conditions.