Application of Hybrid-Electric Propulsion to ‘Large-Cabin’ Business Aircraft

This paper aims to fill a critical cap in hybrid-electric propulsion (HEP) research by investigating the feasibility of its application on a ‘large-cabin’ business aircraft by 2040, for which key requirements are a long range of at least 6297 km (3400 nmi), and a cruise speed of Mach 0.85. Based upon a representative baseline ‘large-cabin’ aircraft, a time-stepping simulation for the distinct phases of an NBAA mission, consisting of takeoff, climb, cruise, landing, and a reserve segment is developed for turbofan, series, and parallel architectures. The simulation enables analysis of range, specific air range, battery weight, battery volume, and energy consumption for various degrees of hybridization and battery specific energy densities. The results find that while both series and parallel architectures are able to meet the requisite range targets, the parallel architecture is better suited as the overall drivetrain weight is lower. The parallel HEP architecture enables the aircraft to fly a maximum distance of 7082 km (3824 nmi), with a 5% energy hybridization. Over a typical 5556 km (3000 nmi) mission this equates to fuel savings of 847 kg compared to a turbofan. The HEP ‘large-cabin’ aircraft is viable provided battery technology reaches a specific energy density of at least 800 Wh/kg.