Integrated Design of a Morphing Winglet for Active Load Control and Alleviation of Turboprop Regional Aircraft

Abstract

Aircraft winglets are well-established devices that improve aircraft fuel efficiency by enabling a higher lift over drag ratios and lower induced drag. Retrofitting winglets to existing aircraft also increases aircraft payload/range by the same order of the fuel burn savings, although the additional loads and moments imparted to the wing may impact structural interfaces, adding more weight to the wing. Winglet installation on aircraft wing influences numerous design parameters and requires a proper balance between aerodynamics and weight efficiency. Advanced dynamic aeroelastic analyses of the wing/winglet structure are also crucial for this assessment. Within the scope of the Clean Sky 2 REG IADP Airgreen 2 project, targeting novel technologies for next-generation regional aircraft, this paper deals with the integrated design of a full-scale morphing winglet for the purpose of improving aircraft aerodynamic efficiency in off-design flight conditions, lowering wing-bending moments due to maneuvers and increasing aircraft flight stability through morphing technology. A fault-tolerant morphing winglet architecture, based on two independent and asynchronous control surfaces with variable camber and differential settings, is presented. The system is designed to face different flight situations by a proper action on the movable control tabs. The potential for reducing wing and winglet loads by means of the winglet control surfaces is numerically assessed, along with the expected aerodynamic performance and the actuation systems’ integration in the winglet surface geometry. Such a device was designed by CIRA for regional aircraft installation, whereas the aerodynamic benefits and performance were estimated by ONERA on the natural laminar flow wing. An active load controller was developed by PoliMI and UniNA performed aeroelastic trade-offs and flutter calculations due to the coupling of winglet movable harmonics and aircraft wing bending and torsion.

Drag Reduction by Wingtip-Mounted Propellers in Distributed Propulsion Configurations

“…To execute a full aerodynamic optimization with acceptable computational cost, an optimization chain which involves a low-fidelity aerodynamic solver, able to consider viscous effects, was used. The chain consists of an optimization tool (GAW) based on the Pareto dominance [37,38], the aerodynamic home-built low-fidelity solver Xavl [39,40] based on the open-source software AVL [41], and a post-processor. The same approach was successfully used in the Scavir project [42], where the low-fidelity results showed a good agreement with the high-fidelity ones.…”

Topology Optimization of Large-Scale 3D Morphing Wing Structures

“…Our results cannot be compared to theirs as they solved different problems and applied external loading to drive their model. However, the work presented here showed the possibility of morphing model structures in 3D and that the result may give an alternative wing structure, compared to the traditional one consisting of ribs, as proposed by [31][32][33].…”

New Aerodynamic Studies of an Adaptive Winglet Application on the Regional Jet CRJ700

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