Performance and energy sizing of a series-hybrid aircraft using a modified energy distribution diagram and energy balance diagram: A case study of a German operator

• Electrifying aviation using state-of-the-art technology levels is challenging. • General aviation (GA) aircraft may benefit from aviation electrification by implementing hybrid configurations. • Short-duration-high-power flight missions can achieve significant emission reduction by electrifying. • Energy distribution and energy balance diagrams play a crucial role in the development of new battery sizing techniques for aviation electrification. In pursuing sustainable aviation, efficient energy management is paramount, particularly for short-duration high-power flights, common in regional transport sectors. This paper presents a novel methodology for sizing batteries in hybrid-electric aircraft, specifically applied to a series-hybrid electric retrofit of the GA8 Airvan operated by Ostfriesischer-Flug-Dienst (OFD), which connects the mainland to Germany's northern islands. The core of the proposed approach lies in an innovative algorithm integrating energy distribution and balance considerations to determine the optimal battery size, balancing performance and weight. The study investigates three different charging scenarios, namely 1) overnight charging, 2) charging after each round trip, and 3) charging after each single flight. These alternative scenarios are designed to accommodate the dynamic nature of flight operations to optimize resource utilization and operational efficiency. Findings indicate that recharging the aircraft's battery after each flight is feasible with current technology; however, this practice may accelerate battery degradation. Incorporating an internal combustion engine (ICE) that can be used during diversions or the second leg of the flight significantly reduces fuel consumption by 34 % compared to today’s aircraft, suggesting hybrid systems could balance operational efficiency and sustainability. This research contributes to efforts to reduce aviation's environmental footprint and foster sustainable practices. The methodologies outlined have the potential to influence future electric and hybrid-electric aircraft design and operation, marking a significant step towards eco-friendly skies.