Unsteady Aerodynamics of the SAGITTA Flying Wing Configuration

The dynamic damping derivatives associated with the pitching and yawing motion of the SAGITTA flying wing configuration at low Mach number conditions are presented. A tailless variant of the configuration and a variant with attached double vertical tail are investigated. The damping derivatives are determined by means of the response of aerodynamic forces and moments to forced harmonic oscillations. The required data for the determination of the damping derivatives is obtained from time-accurate Reynolds-Averaged Navier-Stokes computations. The calculation methodology for the pitch- and yaw-damping derivatives for arbitrary freestream conditions is described and a short evaluation of the approach is presented. Angle of attack and sideslip angle trends as well as the effect of the double vertical tail on the dynamic stability are investigated. For moderate freestream conditions the damping derivatives exhibit an almost constant distribution with respect to the angle of attack and the sideslip angle. With increasing angle of attack and sideslip angle, however, significant non-linear characteristics are observed. The pitch-damping derivatives indicate a dynamically stable behavior for both configurations and all freestream conditions. In contrast, the lateral damping characteristics are much more critical. Both configurations exhibit unstable behavior at several freestream conditions. The vertical tail considerably increases the lateral dynamic stability of the SAGITTA configuration.