Abstract:

The insufficient lateral-directional dynamic stability is a key problem in flying wing configuration aircraft design. An approach to increase the lateral-directional dynamic stability of the flying wing without the augmentation system is proposed, which can improve the lateral-directional stability using only the adjustment of the spanwise dihedral layout without any planform change. The feasibility of the design method is analyzed theoretically. An improved vortex lattice method and the lateral-directional linearized small disturbance equations are used. The development of each lateral-directional mode at various flight conditions is reviewed by root locus charts. To verify the feasibility of the design method described above, a small flying wing aircraft is selected as the study object, and the effect of dihedral layout optimization is revealed. The result of computation  and flight test data indicates that the stability of the Dutch roll mode is enhanced through dihedral layout optimization.