Minimal Induced Drag for Non-Planar Lifting Surfaces with Moderate and Small Aspect Ratio

Kurzfassung

Summary The induced drag of non-planar wings is compared to that of planar wings which result from unfolding the non-planar ones. It is shown that due to the induced lift, there exist non-planar configurations with positive span camber that have an overall aerodynamic performance increase in comparison to the planar ones. The induced lift and increment of aerodynamic performance increases with decreasing aspect ratio. The effect is opposite for configurations with negative camber. Without the induced lift, the positive non-planar configuration would have more induced drag. Analysis is performed using a lifting line method, which takes into account the induced lift, and using Euler solutions. For the inviscid solutions, the induced drag is obtained with a far-field drag analysis method.