Final Report Summary - OMSAMA (Optimisation of Multiscale Structures with Applications to Morphing Aircraft)
The design of efficient morphing aircraft requires advances in system level modelling and performance assessment, innovative and novel structural concepts, and improved components such as compliant skins. All of these aspects were considered in the project and some highlights are summarised below.
The key requirement for the adoption of morphing technology is the demonstration of the potential performance benefits. This requires a system level analysis that considers not only the aerodynamics of the aircraft, but also the sizing and weight estimation for both the structure and actuators, and how the vehicle will be operated. For example, detailed analysis has been performed on aircraft with variable span for combined dash and loiter missions, to determine if the improved aerodynamic performance is able to offset the weight penalty.
Novel configurations investigated include the biologically inspired FishBAC compliant variable camber device, consisting of a chordwise spine with stringers to support a pre-tensioned elastomeric skin. A significant improvement in aerodynamic efficiency (the ratio of lift to drag) has been demonstrated in simulation and wind tunnel testing, for a relatively small increase in weight. A novel span extension concept with a compliant skin has been designed and extensively modelled.
The structures that comprise a morphing aircraft must be understood to enable the system level performance optimisation. Equivalent models are used to capture their characteristics at the system level and must allow for changes in dimensions and geometry. Skins are vital components, and are typically anisotropic to combine stiffness to support the aerodynamic loads, and flexibility to enable deformation. Corrugated and reinforced elastomer skins have been a particular focus within the project.
The design of morphing aircraft continues to be a huge challenge, and this project has made significant advances in understanding the key requirements in the design process. However, modern aircraft are lightweight and highly optimised, and more research is required before morphing can be routinely considered as a design option for commercial aircraft.