A novel adaptive winglet concept was developed to enable controlled cant angle orientation and twist throughout the flight envelope whilst also providing a passive gust loads alleviation capability.
A CFD based aerodynamic design of the device applied on a baseline Turbo-Fan Aircraft configuration model was undertaken, followed by a preliminary lay-out definition of the structure and actuation system required for the device.
Detailed parametric studies were then performed to investigate the performance of the device in terms of both drag and loads alleviation capabilities on its own, and also in combination with conventional control actuators, and both compared to the baseline configuration.
The feasibility of using a morphing wing-tip device to improve the aerodynamic performance of a generic regional turbo-fan jet had been investigated.
Initial studies using CFD based aerodynamics were performed to determine the effect of changing the cant, twist and camber of the morphing wing tip on lift and drag, and also the bending moments acting on the wing-tip and the wing. The trade-off between the aerodynamic performance and the extra weight that would be incurred by an increase in bending moment was encapsulated via the classic range equation. Neural network models were developed to enable computation of the performance characteristics relating to any of the wing-tip parameters, Mach number and Angle of Attack. From these surrogate models it was possible to define the range of wing-tip parameters that were required.
A chiral structure-based solution was designed to enable the required wing-tip deflections. It was found that the device for the cant deflections had to be separate from that required for camber and twist change. The moment requirements for actuation were computed.
A range of different actuation devices were considered, and it was found that most of the requirements could be met using conventional off-the-shelf actuation.
A complete series of static and dynamic gust loads analyses were performed on an aeroelastic finite element model in order to evaluate the device. It was found that it was possible to impart some static gust loads alleviation through stiffening of some parts of the wing-tip.
Inclusion of the device showed that it is possible to achieve gains of up to 5% in aircraft range compared to the baseline structure due to changes in the morphing winglet shape and obtain a reduction in gust load of 2% - 4%.
Further work is required to validate the concept and to test its feasibility experimentally.