Conceptual Design of an Electric Regional Aircraft with a SAF-Fuelled Range Extender

This paper presents the conceptual design and operational framework of the VoltAirs-95, a 95-passenger aircraft with a range of 894 km, developed for the 2024 DLR Design Challenge. The aircraft features distributed electric propulsion, powered by a hybrid-electric powertrain that combines battery packs with a turboshaft generator system for range extension, fuelled by Sustainable Aviation Fuel (SAF). The configuration selection process is carried out through a multi-disciplinary methodical ranking of potential designs, focusing on an achievable configuration to ensure technological readiness for a planned entry into service by 2050. Subsequently, an in-depth analysis of a designated network of European flights is conducted to establish the optimal design point. The concept is characterised by its unconventional powertrain, high aspect ratio wings, V-tail empennage and windowless fuselage. The calculations of the aircraft’s structural mass, aerodynamics, and performance substantiate the design’s feasibility. The aircraft is primarily battery powered, with the range extender providing electric power only for longer range and reserve missions. To address range limitations, the longest routes in the network are operated with a stopover. Deployed to the stated use case travel demand route network, the VoltAirs-95 achieves a 45% reduction in energy consumption and a 94% reduction in greenhouse gas emissions compared to a conventional SAF-powered turboprop aircraft. These outstanding enhancement in sustainability are realised with only a moderate 9% increase in direct operating costs.