Evaluation of a mid-fidelity approach for the calculation of tiltrotor aerodynamic stability derivatives in cruise flight conditions

This paper presents a comprehensive analysis of the static and dynamic behavior of a tiltrotor aircraft using an integrated aeroelastic model to evaluate its stability and control characteristics in cruise flight conditions. A mid-fidelity aerodynamic software, DUST, based on the vortex particle method (VPM), was coupled with the multibody dynamics solver MBDyn to perform both static and dynamic simulations on the Bell XV-15 tiltrotor, equipped with Advanced Technology Blades. A breakdown approach was employed to isolate and assess the contribution of individual components to the overall stability and control of the aircraft. Four rotor models with varying levels of fidelity were developed to investigate the impact of modeling accuracy on the reduced-order representation of the aircraft. Several methods for calculating aerodynamic stability derivatives were applied and validated. This activity enabled to provide a comprehensive quantification of the contributions of individual components to the aircraft's stability, highlighting the capabilities of a mid-fidelity approach to evaluate the critical influence of rotor dynamics on stability derivatives due to the substantial impact of aerodynamic interactions in stability evaluation.