IJAT Vol.16 No.2 pp. 183-196
doi: 10.20965/ijat.2022.p0183


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

Corresponding author

April 22, 2021
October 5, 2021
March 5, 2022
flying car, eVTOL, system design, sustainability, medical emergency

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.

Cite this article as:
Yusuke Mihara, Tsubasa Nakamura, Aki Nakamoto, and Masaru Nakano, “Airframe Design Optimization and Simulation of a Flying Car for Medical Emergencies,” Int. J. Automation Technol., Vol.16, No.2, pp. 183-196, 2022.
Data files:
  1. [1] J. Holden and N. Goel, “Fast-Forwarding to a Future of On-Demand Urban Air Transportation,” Octber 27, 2017. [Accessed March 27, 2021]
  2. [2] M. Nakano, “Future Automobile (2): Assessing an opportunity of Flying Car,” Nihon Keizai Shimbun (Nikkei), Morning edition, March 21, 2019 (in Japanese).
  3. [3] A. Brown and W. Harris, “A Vehicle Design and Optimization Model for On-demand Aviation,” 2018 AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conf., pp. 1-46, 2018.
  4. [4] A. Bacchini and E. Cestino, “Electric VTOL Configurations Comparison,” Aerospace, Vol.6, No.3, Article No.26, doi: 10.3390/aerospace6030026, 2019.
  5. [5] J. M. Utterback and W. J. Abernathy, “A dynamic model of process and product innovation,” Omega, Vol.3, No.6, pp. 639-656, doi: 10.1016/0305-0483(75)90068-7, 1975.
  6. [6] T. H. Ha, K. Lee, and J. T. Hwang, “Large-scale Design-economics Optimization of eVTOL Concepts for Urban Air Mobility,” AIAA Scitech 2019 Forum, doi: 10.2514/6.2019-1218, 2019.
  7. [7] J. T. Hwang and A. Ning, “Large-scale multidisciplinary optimization of an electric aircraft for on-demand mobility,” 2018 AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conf., doi: 10.2514/6.2018-1384, pp. 1-19, 2018.
  8. [8] A. Kasliwal et al., “Role of Flying Cars in Sustainable Mobility,” Nature Communications, Vol.10, Article No.1555, doi: 10.1038/s41467-019-09426-0, 2019.
  9. [9] T. Amago et al., “Optimization technique for first order analysis,” The Japan Society of Mechanical Engineers, The 4th Optimization Symp., No.00-28, pp. 199-204, doi: 10.1299/jsmeoptis.2000.4.199, 2000 (in Japanese).
  10. [10] R. Shishko and R. Aster, “NASA Systems Engineering Handbook,” NASA Special Publication 6105, Rev1, 1995.
  11. [11] German Parliament, “Closing Report of the Enquete Kommission,” 13/11200, Germany, 1998.
  12. [12] K. Ogawa et al., “A process decision making strategy based on sustainability evaluation,” Int. J. Automation Technol., Vol.9, No.1, pp. 51-58, doi: 10.20965/ijat.2015.p0051, 2015.
  13. [13] O. Weck, “Multiobjective optimization: History and promise,” The 3rd China-Japan-Korea Joint Symp. on Optimization of Structural and Mechanical Systems, Invited Keynote Paper, GL2-2, pp. 34-48, 2004.
  14. [14] J. Blank and K. Deb, “Pymoo: Multi-objective optimization in python,” IEEE Access, Vol.8, pp. 497-509, doi: 10.1109/ACCESS.2020.2990567, 2020.
  15. [15] A. Kohama, “Past, present, and future of air ambulances,” J. of Japanese Association for Acute Medicine, Vol.21, No.6, pp. 271-281, doi: 10.3893/jjaam.21.271, 2010 (in Japanese).
  16. [16] M. H. Sadraey, “Aircraft Design, A Systems Engineering Approach,” John Wiley & Sons, ISBN: 978-1-119-95340-1, 2013.
  17. [17] B. Silberg, “Electric Airplanes (batteries included),” The Earth Science Communications Team, NASA’s Jet Propulsion Laboratory, August 22, 2016. [Accessed March 27, 2021]
  18. [18] J. M. Vegh et al., “Current Capabilities and Challenges of NDARC and SUAVE for eVTOL Aircraft Design and Analysis,” AIAA Propulsion and Energy 2019 Forum, doi: 10.2514/6.2019-4505, 2019.
  19. [19],“NACA 0021 (naca0015-il) X foil prediction polar at Re=100,000 Ncrit=9,” 2020. [Accessed March 27, 2021]
  20. [20] HELIX, “Propeller Datasheets.” [Accessed March 27, 2021]
  21. [21] G. Leishman, “Principles of Helicopter Aerodynamics,” 2nd edition, Cambridge University Press, ISBN: 9781107013353, 2006.
  22. [22] J. S. Duncan, “Pilot’s Handbook of Aeronautical Knowledge,” Federal Aviation Administration, U.S. Department of Transportation, FAA-H-8083-25B, ISBN: 1602397805, 2016.
  23. [23] E. Hendricks et al., “Multidisciplinary optimization of a turboelectric tiltwing urban air mobility aircraft,” AIAA Aviation 2019 Forum, doi: 10.2514/6.2019-3551, 2019.
  24. [24] C. Courtin et al., “Feasibility Study of Short Takeoff and Landing Urban Air Mobility Vehicles using Geometric Programming,” 2018 AIAA Aviation Technology, Integration, and Operations Conf., doi: 10.2514/6.2018-4151, 2018.
  25. [25] K. Sumitani et al., “Development of vehicle fluid dynamics: Flow around the vehicle and aerodynamic characteristics,” J. of Japan Society of Fluid, Vol.23, No.6, pp. 445-454, doi: 10.11426/nagare1982.23.445, 2004 (in Japanese).
  26. [26] T. C. O’Bryan, “An Investigation of the Effect of Downwash from a VTOL Aircraft and a Helicopter in the Ground Environment,” NASA Technical Note, D-977, 1961.
  27. [27] M. Nakadate, “The Aerodynamics Problems in Aircraft,” Aeronautical and Space Sciences Japan, Vol.45, No.521, pp. 314-319, doi: 10.2322/jjsass1969.45.314, 1997 (in Japanese).
  28. [28] N. Rajaratnam, “Turbulent Jets,” Elsevier, ISBN: 0080869963, 1976.
  29. [29] Y. Zhang et al., “The computational fluid dynamic modeling of downwash flow field for a six-rotor UAV,” Frontiers of Agricultural Science and Engineering, Vol.5, No.2, pp. 159-167, doi: 10.15302/J-FASE-2018216, 2018.
  30. [30] Minister of Land, Infrastructure, Transport and Tourism, “Law of Aviation, Article 79, Installation Criteria 8,” 1952 (in Japanese).
  31. [31] Y. Koizumi, “Roles and issues of an air ambulance,” Faculty of Social Sciences, Special Edition, pp. 73-85, 2011.
  32. [32] K. Shinohara, “Investigation on the problems for developments of aviation transportation medical service,” The Japanese J. of Ergonomics, Vol.49, Supplement Edition, pp. 110-111, doi: 10.5100/jje.49.S110, 2013.
  33. [33] P. Pradeep and P. Wei, “Energy-efficient arrival with RTA constraint for multirotor eVTOL in urban air mobility,” J. of Aerospace Information Systems, Vol.16, No.7, pp. 263-277, doi: 10.2514/1.I010710, 2019.
  34. [34] X. Chen et al., “An Overview of Lithium-ion Batteries for Electric Vehicles,” 2012 10th Int. Power & Energy Conf. (IPEC), pp. 230-236, doi: 10.1109/ASSCC.2012.6523269, 2012.
  35. [35] New Energy and Industrial Technology Development Organization, “Toward Formulation of the Technology Strategy in the Field of the EV’s Battery,” Technology Strategy Center, October, 2015 (in Japanese). [Accessed March 27, 2021]
  36. [36] The Society of Japanese Aerospace Companies, “Survey Report of the Helicopter Operation 1988,” 1988.
  37. [37] Toyota City, “Solutions for Noise and Vibration,” Environment Department, Environmental Conservation Division, Toyota City Hall, November 6, 2018 (in Japanese). [Accessed March 27, 2021]
  38. [38] “MD Helicopters, MD902, Technical Description,” Department of Sales and Marketing, MD Helicopters, Inc., 74pp., February 14, 2014. [Accessed March 27, 2021]

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