Airframe Design Optimization and Simulation of a Flying Car for Medical Emergencies
Yusuke Mihara, Tsubasa Nakamura, Aki Nakamoto, and Masaru Nakano
Department of System Design and Management, Keio University
Collaboration Complex, 4-1-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8526, Japan
In terms of future transportation, flying cars are envisioned not only as air taxis but also as air ambulances. Flying cars such as urban air mobility vehicles, passenger drones, and electrical vertical take-off and landing (eVTOL) aircrafts have the potential to relieve seriously congested ground traffic in cities via direct point-to-point air movements. To date, conventional research in which the airframe of a flying car is optimized for use in medical emergencies has not identified a sustainable solution. The purpose of this study is to verify the technical applicability of a flying car for use in medical emergencies. The weighted sum method is used to optimize the design of multi-rotor, vectored-thrust (tilt-rotor), and lift + cruise types of flying cars. A simulation scenario that considers cruising speed and flight height is conducted based on an analysis of stakeholder interviews with a pilot, an in-flight doctor, and an operating company. To optimize the parameters of a flying car airframe, four objective functions, namely the energy required for a round trip, noise value from rotors, downwash speed from rotors, and landing area size, are chosen because the results of a requirement analysis revealed that they were significant for the sustainability of the flying car system. The results of the simulation reveal that the required battery energy densities for all three types exceed the current lithium-ion battery capacities. Therefore, an upgrade in battery capacity is critical for the realization of a flying car. Although the noise level is found to be less than that of a conventional helicopter, it is necessary to develop a rotor to decrease noise levels for environmental reasons. Finally, both the downwash speed and landing area of a flying car are estimated to be less than those of a conventional helicopter, making it possible for the flying car to land in tight spaces.
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