Impact of Propulsion Technology Levels on the Sizing and Energy Consumption for Serial Hybrid- Electric General Aviation Aircraft

Serial hybrid-electric propulsion systems combine the advantages of combustion engines and electric motors. Additionally, they offer new design freedom. In the medium term, this technology might be the solution to more eco-friendly aviation. In this paper, the key technology parameters of general aviation aircraft with such powertrains are analyzed concerning their influence on maximum take-off mass and primary energy consumption. Besides, technological thresholds will be identified. It is found that a power-to-weight ratio increase of electric motors does not yield as large improvements as expected and that fully electric powertrains are the best solution for aircraft designed to minimum primary energy usage once a certain battery energy density is exceeded.