Aerodynamic Performance of Two eVTOL Concepts

Abstract

Today’s demand for urban mobility is constantly growing due to the demographic changes observed in metropolitan areas. New concepts such as electrical vertical take-off and landing (eVTOL) vehicles are currently emerging. Therefore an aerodynamic investigation of two eVTOL vehicle concepts is carried out to identify the advantages and disadvantages of these new types of vehicles. Two flying vehicles have been loosely re-engineered. The first vehicle is a quadcopter with co-axial rotors on each arm, while the other vehicle features two tilt-wings which are immersed in the slipstream of four propellers each. Both vehicles have been considered in their original configuration with eight, but also in a reduced variant with four propellers. Findings of these studies are that RPM controlled thrust leads to a more efficient operation of the rotors for various thrust settings. In case of the tilt-wing concept, the wing is beneficial in hover and forward flight, as it acts as a stator and increase the efficiency of the rotors. Lastly, the transport performance of both vehicles is compared with a conventional helicopter design that is electrified. The outcome is that the coaxial quadcopter requires the least energy per distance, while the tilt-wing concept has the greatest range.