Efficient Mid-Fidelity Aerodynamic Modeling of a Tilt-Wing eVTOL for Control Applications

Kurzfassung

Urban and regional air mobility have the potential to become important modes of transportation in the future and thus currently attract a lot of attention. Tilt-wing electric vertical takeoff and landing vehicles (eVTOLs) appear to be especially suited in this context as they combine hover capability with efficient cruise flight. However, the development and validation of control concepts require a reasonably accurate yet performant aerodynamic model of the aircraft. In order to obtain representative aerodynamic models of eVTOL aircraft at comparatively low efforts and equipment demands, this work adapts the sequential rapid aero modeling (RAM) process using a mid-fidelity numerical tool DUST. Design of experiment and mid-fidelity numerical simulation reduce the computational cost of aerodynamic data generation. Stepwise regression is used to fit the data into a coefficient model. In addition to the total aero-propulsive model, an aerodynamic model decoupled from propulsion forces and moments is identified. The latter is simplified by assuming that the influence of the rotors on the aerodynamic forces and moments depends solely on the thrust. The process is demonstrated on a tandem tilt-wing configuration similar to the Airbus A3 Vahana, where an aero-propulsive model is efficiently identified. Moreover, a model decoupled from the propulsion forces and moments is obtained. For evaluation, an analysis of aero-propulsive coefficients and a trim study are performed. Two ways to achieve a steady-state transition trajectory are proposed, each using a combination of differential thrust and differential tilt.