Design of a retrofit winglet for transport aircraft with assessment of cruise and ultimate structural loads

Abstract

In this work retrofit winglets are designed for a transonic aircraft. The used geometry is a generic twin engine aircraft. In a first step winglets are designed using a lifting line method along with RANS solutions. L/D is optimized by taking into account a certain wing root bending moment reserve for the reference wing. The final analysis includes wing deformation studies by means of flow structure coupling. Therefore a finite element model has been developed with respect to standard loadings of certification autority. Using the flow structure coupling process RANS solutions with deformed wing shapes are obtained for cruise conditions in order to determine the influence of deformation on performance and for a 2.5g load case in order to evaluate ultimate structural loading. Comparing the results of rigid wing with the deformed wing the wing root bending moment and the bending moment of the device is clearly reduced for the deformed wing. Thereby the advantage to which an implementation of the described method for future design processes would lead becomes apparent.