Investigation on improving longitudinal static stability of a blended wing body aircraft

The blended wing body (BWB) aircraft as a novel aircraft configuration has a poor longitudinal static stability. A V-tail is installed on the BWB to improve the longitudinal static stability, which achieves the limited improvements. Therefore, the BWB is investigated to further improve the longitudinal static stability with experimental tests and numerical simulations in this paper. The variation with angle of attack (AOA) α of the pitching moment coefficient (C_m) is divided into three regions, i.e., the first AOA region with static stability, the AOA region with static instability, and the second AOA region with static stability. It is found that the position of the forebody vortex acting on the V-tail surface is closely related to the longitudinal static stability of the BWB aircraft. Through increasing the spanwise distance of the V-tail to change the position of the forebody vortex acting on the V-tail surface, the AOA region with static instability is decreased. The longitudinal static stability of the BWB aircraft is improved. The evolution of associated pressure distributions, flow separations and vortical structures is presented in detail.