Generic Design Methodology for Vertical Takeoff and Landing Aircraft with Hybrid-Electric Propulsion

This paper proposes a conceptual methodology for designing vertical takeoff and landing aircraft with a hybrid-electric propulsion system as an alternative to facilitate intercity missions for urban air mobility. Four new modules are developed to consider the diversity of configurations, flight mechanisms, and hybrid-electric propulsion system architectures. The flight-analysis module is proposed to account for various lift- and thrust-generating devices. The hybrid-electric propulsion system sizing module is modified for the vertical takeoff and landing aircraft by additionally considering transition flight. Based on a new proposed battery charge/discharge criterion, the mission-analysis module is constructed to predict the battery capacity and fuel consumption required for a given mission. The weight-estimation module is also developed considering the weight of the mechanical and electric powertrains. The proposed methodology is demonstrated by designing an urban air mobility vehicle and comparing the results with those of other sizing tools. A systematic comparative study and design optimization are carried out to highlight the improvement in the performance of the hybrid-electric-powered vertical takeoff and landing aircraft compared to its battery-driven counterpart. The extended mission range of the designed aircraft presents the possibility of intercity urban air mobility vehicles.