Studies on Morphing Wing for Small Unmanned Aerial Vehicles

Abstract

Birds optimize their fight by transforming the shape of their wings, via slight changes to the geometry parameters like the area, sweep, span, and cross-section. This avian ability to transform the shape of their wings gave rise to the concept of morphing. In general, studies on the wings of aircraft geared towards morphing as the proof-of-concept exists in nature in the form of birds. The wing can be morphed in three ways - planform, out-of-plane, and airfoil morphing. The technology readiness level is still very low to implement morphing as technology in large scale aircraft but morphing can be demonstrated on small unmanned aerial vehicles (SUAV) using existing or near-term technology. Morphing the wing cross-section/airfoil offers a possibility of using different airfoils during the flight mission of the SUA The main objective of this thesis is to explore the feasibility of morphing between existing families of airfoils (i.e., to morph an airfoil into another airfoil) through two different camber morphing methodologies i.e., Discrete Element Method (DEM) and Beam-like bending method (BBM). NACA 0012, a symmetrical airfoil from the NACA 4-digit family and Eppler 201(E201) { an asymmetric airfoil from the Eppler family were chosen as the base and target airfoils to demonstrate airfoil morphing, in this study. E201 was used in the LAURA SUAV and is a low Reynolds number airfoil whose maximum thickness is equivalent to the base airfoil, and it has a maximum camber of 3.1% of the chord. The target airfoil was used to scale the amount of morphing and as the yardstick to evaluate the aerodynamic performance of morphed airfoils. In DEM, a base airfoil is morphed into the target airfoil via modification of its camber without any alteration to its thickness by modeling discrete, rotating elements at multiple locations along the chord. The first and second locations for morphing were chosen based on the target airfoil geometry and the third location corresponds to the position of the conventional plain ..