Design of a Morphing Airfoil for a Light Unmanned Aerial Vehicle Using High-Fidelity Aerodynamics Shape Optimization

Abstract

An in -house high -fidelity aerodynamic shape optimization computer program based on a computational fluid dynamics solver with the Spalart -Allmaras turbulence model and a sequential quadratic programming algorithm is used in order t o obtain a set of optimal airfoils at the different stages of flight of a light unmanned air vehicle. For this study, the airfoil requirements at stall, takeoff run, climb gradient, rate of climb, cruise and loiter conditions are obtained . Then, t he aerody namic shape optimization program is used to obtain the airfoil that has the optimal aerodynamic characteristics at each one of the se stages of flight. Once the optimal airfoils at each stage of flight are obtained, the results are analyzed in order to gain a better understanding of the most efficient initial airfoil configuration and the possible mechanisms that could be used to morph the single element airfoil. The results show that a very thin airfoil could be used as the initial configuration. Furthermor e, a morphing mechanism that controls the camber and leading edge thickness of the airfoil will almost suffice to obtain the optimal airfoil at most operating conditions. Lastly, the use of the optimal airfoils at the different stages of flight significant ly reduce s the installed power requirements, thus enabling a greater flexibility in the mission profile of the unmanned air vehicle.