Composite materials that could form the skin of a morphing aircraft have been tested for their suitability for a shape-changing winglet that would deliver improved aircraft performance.
Researchers at the UK's University of Bristol carried out bending and torsion tests on commercial composite products Kevlar, Hexweb and HexPly. Corrugated composite structures using these products were found to be a possible solution to creating skins that stretch to match the winglet's shape change.
The skins' method of manufacture was also analysed. The concept winglet is described as having polymorphing capability because it could bend and twist instead of changing shape in only one direction.
The work was conducted as part of the Airbus and UK government Engineering and Physical Sciences Research Council-supported Morphing Winglet project.
Winglets that change shape during the different phases of flight are expected to double the efficiency gains that existing fixed winglets can provide an aircraft. Benefits are expected to include optimised lift to drag ratios for increased flight stability at low speeds, reduced aerodynamic noise and better engine-out performance.