Computational fluid dynamic (CFD) approaches were implemented on prop-uninstalled and prop-installed configurations of a flying wing unmannel aerial vehicle (UAV)

so as to solve the problem of the decline of the maximum lift-drag ratio

and the results obtained through numerical methods were shown to be in good agreement with the test data. The impacts of the installation of the propeller on the aerodynamic performances of the aircraft were studied in depth on the basis of the collaborative experiment and numerical research. Detailed analysis of the numerical results indicated that the lowest pressure areas at the aft part of the airframe generated by the aerodynamic interactions between the propeller blades and airframe led to the increase of the drag and hence a decrease of around 30.7% in maximum lift-drag ratio. The feasibility of center shaft extension can effectively reduce the lowest pressure areas at the aft part of the airframe and increase the maximum lift-drag ratio of the aircraft by 17.3% and 15.4% at the angles of attack of 8° and 9°

respectively.