Effect of Wing Flexibility and Bending-Torsion Coupling on Roll Behavior of Wings Incorporating Flared Folding Wingtips

Flared Folding Wingtips (FFWTs) on high aspect ratio wings have been shown to achieve airport taxiway and gate width restrictions whilst improving aerodynamic performance without any substantial gain in structural weight. Previous numerical and experimental studies on relatively stiff wings have shown that including a FFWT improved aircraft roll performance; however, subsequent numerical studies on a very flexible transonic aircraft model showed that the FFWT sdegradedroll performance. This work considers why these two differing conclusions were achieved and finds that it is not only the flexibility of the wings and dynamic pressure that must be considered but also, most importantly, the coupling between bending and torsion. Several numerical simulations with varying bending-torsion coupling, wing sweep and airspeed are performed to reinforce the findings.