Aerodynamic optimisation of a camber morphing aerofoil

Abstract

An aircraft that has been carefully optimised for a single flight condition will tend to perform poorly at other flight conditions. For aircraft such as long-haul airliners, this is not necessarily a problem, since the cruise condition so heavily dominates a typical mission. However, other aircraft such as UAVs, may be expected to perform well at a wide range of flight conditions. Morphing systems may be a solution to this problem, as they allow the aircraft to adapt its shape to produce optimum performance at each flight condition. Optimisation of morphing aerofoils is typically performed separately to the morphing mechanism design. In this work, an optimisation strategy is developed to account for a known possible morphing system within the aerodynamic optimisation process itself. This allows for the limitations of the system to be considered from the start of the design process. The Fishbone Active Camber (FishBAC) camber morphing system is chosen as the example mechanism, and it is shown that the FishBAC can achieve large improvements in performance over non-morphing aerofoils when multiple flight conditions are considered. Additionally, its performance is compared to an aerofoil whose shape can change arbitrarily (as if a perfect morphing mechanism can be designed), and it is shown that the FishBAC performs nearly as well, despite being a relatively simple mechanism.