IEEE Electrification Magazine - June 2020 - 26

Taking a different approach, a team from the Center
for High-Efficiency Electrical Technologies for Aircraft,
led by the University of Illinois at Urbana-Champaign,
is currently developing concepts for a fully electric aircraft. This concept uses hydrogen energy storage and a
fuel cell/battery hybrid system to achieve payload and
range capabilities commensurate with modern singleaisle transport aircraft. Since the hydrogen is stored as
a cryogenic liquid, this medium is also used as a means
to achieve superconducting power transmission and
motor systems. The aircraft is configured with a distributed overwing ducted fan system to promote the benefits of boundary-layer ingestion, improve robustness to
component failures, and improve takeoff and landing performance.
Due to the aggressive power requirements of a twinaisle aircraft configuration, very few concepts have
broached this large class of aircraft. However, the NASA
N3-X is one concept where distributed-electric propulsion
was used at this scale. The N3-X is fully turboelectric and
utilizes a superconducting electrical system with a blended wing body configuration. The aircraft features two
30-MW turbogenerators, one at each wingtip of the aircraft, and 14 motor-driven ducted fans mounted overwing
on the fuselage surface.

Conclusions
Electric propulsion offers a new paradigm for aircraft
design and operations not offered under previous configurations. While a number of technological challenges
exist to making electric propulsion realizable at commercial scales, the benefits of reduced costs, decreased emissions, and improved flexibility of operation serve as
attractive motivations for developing these new technologies. Advancements in energy storage systems, high-power electrical systems and components, and matured
methods for synergistic propulsion integration will pave
the way for the electric aircraft of the future.
It is worth noting that scaling existing technologies to
higher-rated power capabilities is not the only consideration when introducing electric aircraft into the aviation
community. To date, no electric aircraft has been certified
for commercial use with passengers. This certification
process is already time intensive and costly for conventional aircraft, but it is expected to be particularly laborious for cases of electric aircraft propulsion systems due
to the lack of precedent and data on reliability and safety.

the ground would result in a required 26% increase in
global electricity production, and airports will have to be
equipped with appropriate charging infrastructure. These
indications demonstrate that air transportation is an
interconnected aspect of modern life. Fostering the development of electric aviation in a fashion that is environmentally responsible, economically sustainable, and
technically viable requires extensive coordination across
international communities as well as creative thinking
that goes beyond conventional wisdom.

For Further Reading
National Academies of Sciences, Engineering, and Medicine,
Commercial Aircraft Propulsion and Energy Systems Research:
Reducing Global Carbon Emissions. Washington, D.C.: National
Academy Press, 2016. doi: 10.17226/23490.
G. E. Wroblewski and P. J. Ansell, "Mission analysis and
emissions for conventional and hybrid-electric commercial
transport aircraft," J. Aircr., vol. 56, no. 3, pp. 1200-1213, 2019.
doi: 10.2514/1.C035070.
B. J. Brelje and J. R. R. A. Martins, "Electric, hybrid, and turboelectric fixed-wing aircraft: A review of concepts, models,
and design approaches," Progress Aerosp. Sci., vol. 104, pp. 1-19,
Jan. 2019. doi: 10.1016/j.paerosci.2018.06.004.
X. Zhang, C. L. Bowman, T. C. O'Connell, and K. S. Haran,
"Large electric machines for aircraft electric propulsion," IET
Electr. Power Applicat., vol. 12, no. 6, pp. 767-779, 2018. doi:
10.1049/iet-epa.2017.0639.
K. S. Haran et al., "High power density superconducting
rotating machines: Development status and technology roadmap," Supercond. Sci. Technol., vol. 30, no. 12, pp. 1-41, 2017. doi:
10.1088/1361-6668/aa833e.
C. Pornet and A. T. Isikveren, "Conceptual design of hybridelectric transport aircraft," Progress Aerosp. Sci., vol. 79, pp. 114-
135, Nov. 2015. doi: 10.1016/j.paerosci.2015.09.002.
R. Jansen, C. Bowman, A. Jankovsky, R. Dyson, and J. Felder,
"Overview of NASA electrified aircraft propulsion (EAP)
research for large subsonic transports," in Proc. 53rd AIAA/
SAE/ASEE Joint Propulsion Conf., Atlanta, GA, July 10-12, 2017,
Art. no. 2017-4701. doi: 10.2514/6.2017-4701.
A. H. Epstein and S. M. O'Flarity, "Considerations for reducing aviation's CO2 with aircraft electric propulsion," J. Propulsion Power, vol. 35, no. 3, pp. 572-582, 2019. doi: 10.2514/1.
B37015.
B. Yutko and J. R. Hansman, "Approaches to representing
aircraft fuel efficiency performance for the purpose of a commercial aircraft certification standard," MIT International Center for Air Transportation, Cambridge, MA, Rep. no.
ICAT-2011-05, May 2011.
"Global market forecast: Cities, airports & aircraft: 2019-
2083," Airbus, Leiden, The Netherlands, 2019. [Online]. Available: https://www.airbus.com/content/dam/corporate-topics/
strategy/global-market-forecast/GMF-2019-2038-Airbus
-Commercial-Aircraft-book.pdf

For airlines to make a strategic shift to electric aircraft,
there must be an economic viability in this operation

Biographies

model. If this viability is achieved, then a fundamental

Phillip J. Ansell (ansell1@illinois.edu) is with the Depart-

shift to fleets of electric aircraft could change the eco-

ment of Aerospace Engineering, University of Illinois at

nomic model that is used in aircraft acquisition, schedul-

Urbana-Champaign.

Kiruba S. Haran (kharan@illinois.edu) is with the

ing, and profitability.
Readiness of electric aircraft would also require devel-

Department of Electrical and Computer Engineering, Uni-

opments in the international power grid. Recent studies

versity of Illinois at Urbana-Champaign.

have indicated that displacing aviation energy usage to

I E E E E l e c t r i f i cati o n M agaz ine / J UN E 2020

https://www.airbus.com/content/dam/corporate-topics/strategy/global-market-forecast/GMF-2019-2038-Airbus-Commercial-Aircraft-book.pdf https://www.airbus.com/content/dam/corporate-topics/strategy/global-market-forecast/GMF-2019-2038-Airbus-Commercial-Aircraft-book.pdf https://www.airbus.com/content/dam/corporate-topics/strategy/global-market-forecast/GMF-2019-2038-Airbus-Commercial-Aircraft-book.pdf

IEEE Electrification Magazine - June 2020

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