Concept and design of a high power dense propulsion system for electric aircraft

The present thesis proposes a conceptual design of a tiltable propulsion system for the ALBACOPTER® 1.0, an eVTOL aircraft with a take-off mass of800 kg. Usually, the propulsion systems of eVTOLs are direct drives due to their simple design. However, since the propeller thrust in relation to the take-off mass is the most important criterion for vertical take-off aircraft, power-dense drives are of maximum importance. Therefore, a propeller drive concept combining a high-performance synchronous machine with a gearbox is developed and investigated with regard to its performance. For this purpose, all boundary conditions are determined. First, the propeller is simulated in order to define its relevant speeds and gear’s reduction ratio. Then the aerodynamic loads are estimated using data from wind tunnel tests and CFD simulations and qualitatively compared with own wind tunnel tests. It is shown that the moments induced by oblique propeller inflow play a significant role compared to the lateral forces. By calculating and classifying these and other potential loads, concepts for the drive train and the tilt actuator are developed and evaluated.