Rigid-elastic-coupled aeroservoelastic modeling and flight test verification of a flexible flying-wing aircraft

This paper presents a novel approach of aeroservoelastic modeling coupled with flight dynamics for a flexible flying-wing aircraft in a body frame of reference. The modeling approach fully encompasses the dynamic coupling among the aircraft rigid-body motions, elastic vibrations and control-surface deflections. The coupled dynamic equations derived are in terms of the quasi-coordinates of a set of Lagrange equations, the nodal coordinates of a finite-element model for the aircraft and the aerodynamic variables based on aerodynamic derivative matrices. The attractive feature of the modeling approach is that it maintains complete consistency with classical flight dynamics formulations and is compatible with the finite-element model of high-fidelity. To validate the present modeling approach, the paper provides the body-freedom flutter computations of a flexible flying-wing aircraft via the present modeling method and corresponding flight tests. The numerical computations show small relative errors in the airspeed and frequency of body-freedom flutter, as well as closely matching flutter configurations compared to the flight tests.