The University of Illinois has announced that NASA is underwriting a project to develop a cryogenic hydrogen fuel cell system for powering all-electric aircraft. Funded by a three-year, US$6 million contract, the Center for Cryogenic High-Efficiency Electrical Technologies for Aircraft (CHEETA) will investigate the technology needed to produce a practical all-electric design to replace conventional fossil fuel propulsion systems.

The jet engine in all its variations has revolutionized air travel, but with airline profit margins running wafer thin in these ecologically conscious times, there's a lot of interest in moving away from aircraft powered by fossil fuels and toward emission-free electric propulsion systems that aren't dependent on petroleum and its volatile prices.

The CHEETA project is a consortium of eight institutions that include the Air Force Research Laboratory, Boeing Research and Technology, General Electric Global Research, Ohio State University, Massachusetts Institute of Technology, the University of Arkansas, the University of Dayton Research Institute, and Rensselaer Polytechnic Institute. Although the project is still in its conceptual stage, the researchers have a firm vision of the technology and its potential.

"Essentially, the program focuses on the development of a fully electric aircraft platform that uses cryogenic liquid hydrogen as an energy storage method," says Phillip Ansell, assistant professor in the Department of Aerospace Engineering at Urbana-Champaign who is the project's principal investigator. "The hydrogen chemical energy is converted to electrical energy through a series of fuel cells, which drive the ultra-efficient electric propulsion system. The low temperature requirements of the hydrogen system also provide opportunities to use superconducting, or lossless, energy transmission and high-power motor systems.

"It's similar to how MRIs work, magnetic resonance imaging. However, these necessary electrical drivetrain systems do not yet exist, and the methods for integrating electrically driven propulsion technologies into an aircraft platform have not yet been effectively established. This program seeks to address this gap and make foundational contributions in technologies that will enable fully electric aircraft of the future."

The team points out that though progress has been made, there are many basic problems that need to be overcome before we see such electric aircraft taking to the skies.

"Advances in recent years on non-cryogenic machines and drives have brought electric propulsion of commercial regional jets closer to reality, but practical cryogenic systems remain the 'holy grail' for large aircraft because of their unmatched power density and efficiency," says Associate Professor Kiruba Haran of the Department of Electrical and Computer Engineering at the University of Illinois. "The partnerships that have been established for this project position us well to address the significant technical hurdles that exist along this path."

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