Preliminary investigation of use of flexible folding wing tips for static and dynamic load alleviation

A recent consideration in aircraft design is the use of folding wing-tips with the aim of enabling higher aspect ratio aircraft with less induced drag, but also meeting airport gate limitations. This study investigates the effect of exploiting folding wing-tips in-flight, as device to reduce both static and dynamic loads. A representative civil jet aircraft aeroelastic model was used to explore the effect of introducing a wing-tip device, connected to the wings with an elastic hinge, on the loads behavior. For the dynamic cases, vertical discrete gusts and continuous turbulence were considered. The effect of hinge orientation, stiffness, damping and wing-tip weight on the static and dynamic response was investigated. It was found that significant reductions in both the static and dynamic loads were possible. For the case considered, a 25% increase in span using folding wing-tips resulted in almost no increase in loads.