Investigation and Minimization of Upsweep Drag of Aft-Loading Military Transporters with Tail Strakes

The use of tail strakes on aft loading transport aircraft is a well proven technique to reduce fuselage upsweep drag. In the present paper the tail flow around a generic aircraft configuration with a swept up tail has been computed using high fidelity CFD analyses. The focus was on the influence and effectiveness of tail strakes and the interaction of the strake with the tail vortices. As it turned out that strakes placed arbitrarily may lead to decrease of aircraft performance, CFD based optimization runs were conducted to find an optimal strake position on the rear fuselage. Finally the optimized configurations were analyzed and the principle of strake tail vortex interaction aiming on a reduction of upsweep drag was clarified.