Stability Modelling of Vertical Take Off for Novel Configurations

There has been increasing interest in recent years to develop Vertical-Take-Off ( and Landing VTOL) aircraft with substantially improved range and speed performance compared to a helicopter. This requires the transition from vertical/hover to efficient forward flight. The development of tiltrotor aircraft such as the AW609 project have highlighted the difficulty in predicting the dynamics of such aircraft. Similar problems can be expected for many electric urban VTOL currently being developed and tested. The dynamics of these types of aircraft are unique, and current stability models rely heavily on experimental data acquired from unmanned test drones. This precludes all but the most basic stability analysis from the design stage. The main challenges identified in the development of an analytical stability model are the accurate representation of the rotor wake aerodynamics and the lack of consideration of time-history effects in classical stability analysis. This research addresses the latter issue by identifying new periodic aerodynamic reduced order modelling techniques and the development of robust methods to identify stability problems associated with discretisation rather than physical processes. The model problem used will initially be a tiltrotor but an electric VTOL partner is currently being pursued.