A novel multi-body architecture for wing flap camber morphing

The increase of lift force required by an aircraft during take-off and landing phases is conventionally obtained through wing flap deflection. Such devices are usually driven by control systems made of robust actuators and control lines that significantly contribute to the weight of the whole wing structure and, whereas proper external fairings are needed, also to wing friction drag and aerodynamic noise. Moreover, the shape change locally induced by flaps to wing airfoils is clearly limited to the allowable flaps excursion; it follows that, in operative conditions, only a discrete set of few airfoil shapes can be achieved, each shape being related to a precise flap deflection angle within the allowable range. The naturally foreseen advantages of an adaptive high lift device able to smoothly change its shape according to flight conditions as well as the intent of reducing friction drag and emitted aerodynamic noise in take-off and landing, all represented valid motivations for the assessment of a novel flap technology. In the framework of the Low Noise Configuration domain of the Clean Sky – GRA ITD, the authors proved the feasibility of a morphing architecture enabling the controlled camber variation of a flap segment in compliance with top-level requirements pertinent to the next generation Green Regional Aircraft. The architecture is characterized by an Al-alloy multi-body morphing structure based on articulated ribs driven by electro-mechanical actuators. By referring to specific aerodynamic requirements in terms of target shapes and external loads expected in service, the structural layout of the device was preliminarily defined. Advanced FE analyses were then carried out in order to properly size the load-carrying components of the structure and the actuation system. Design performances were finally validated by experimental tests carried out on a true-scale prototype. The experimental campaign covered functionality, static and dynamic tests; obtained results showed high correlation levels with respect to numerical expectations thus proving the compliance of the device with design requirements as well as the goodness of modelling approaches implemented during the design phase.