Initial Sizing for a Family of Hybrid-Electric VTOL General Aviation Aircraft

Abstract

For vertical take-off and landing (VTOL) aircraft, the power needed for vertical take-off is much greater than the power needed for cruise. This power-matching problem can be solved with a balanced hybrid-electric propulsion system. However, there is a trade-off between take-off weight, wing loading, battery technology and range. This paper applies a new initial sizing algorithm for transitioning VTOL aircraft with hybrid-electric propulsion systems, including serial-hybrid and parallel-hybrid configurations. Exemplarily, a family of transitioning VTOL aircraft, intended for urban air mobility (air taxi) operations is designed. Results indicate that hybrid-electric propulsion systems must be considered for future mid-range VTOL aircraft. Very short missions favor fully electric propulsion systems, as this configuration avoids the complexity of a hybrid.