A Performance Comparison of eSTOL and eVTOL Aircraft

Abstract

View Video Presentation: https://doi.org/10.2514/6.2021-3220.vid Electric short takeoff and landing (eSTOL) aircraft and electric vertical takeoff and landing (eVTOL) aircraft are being developed for missions where availability of ground infrastructure is a critical design driver. Because eSTOL aircraft can generate high effective lift coefficients through the interaction of the wing, flaps, and distributed propellers they can achieve takeoff and landing distances comparable with the ground footprint proposed for eVTOL facilities. eSTOL aircraft require smaller propulsion systems and less energy for takeoff and landing than eVTOL aircraft, which in turn translates to reduced vehicle weight or increased payload, range, and/or speed. This paper compares the performance difference between eSTOL and eVTOL aircraft, for both hybrid- and battery-electric propulsion architectures. Both tilt-duct and tilt-rotor eVTOL configurations are examined. For aircraft with an equivalent weight and span to proposed eVTOLs, eSTOL aircraft are able to carry 1.8-2.6x the payload at the same speed and range, depending on the eVTOL type and propulsion system architecture. This number is sensitive to eVTOL disk loading, design mission, and modeling of blown wing performance. The benefit of eSTOL arises primarily from reduced propulsion system weights and reduced energy consumption in the takeoff and landing phases. This benefit varies significantly with design ground footprint and payload; and less so with range and speed.