Abstract
This work presents comparative experimental investigations into the aerodynamics of the recently proposed Fish Bone Active Camber morphing structure. This novel, biologically inspired concept consists of four main elements: a compliant skeletal core, a pre-tensioned elastomeric matrix composite skin, an antagonistic pair of tendons coupled to a non-backdriveable spooling pulley as the driving mechanism, and a non-morphing main spar. The Fish Bone Active Camber concept is capable of generating large changes in airfoil camber and is therefore proposed as a high-authority morphing solution for fixed-wing aircraft, helicopters, wind turbines, tidal stream turbines, and tilt-rotors. This testing compares a baseline airfoil employing a conventional trailing edge flap to a continuous morphing trailing edge using the Fish Bone Active Camber concept. Testing is performed in the low-speed wind tunnel at Swansea University over a range of camber deformations and angles of attack. Both approaches are capable of generating similar levels of lift coefficient; however, comparison of the drag results shows a significant reduction for the Fish Bone Active Camber geometry. While purely two-dimensional flow was not achieved due to restrictions of the tunnel, the two airfoils operated in similar flow environments, allowing for a direct comparison between the two. Over the range of angles of attack typically used in fixed and rotary wing applications, improvements in the maximum obtainable lift-to-drag ratio on the order of 20%–25% are shown.