NASA Prototypes X-57 All-Electric Airplane

Article By : George Leopold

A veteran pilot endorses the NASA concept of electric planes, but notes the energy density gap is going to be prohibitive...

We’ve reported extensively on the rapidly maturing and scaling of electric vehicles. Researchers are also looking at other modes of transportation that could be powered by electric motors, up to and including all-electric airplanes.

While NASA (the first “A” in the space agency’s acronym stands for “Aeronautics”) is devoting valuable supercomputing resources to model and simulate a new prototype, commercial aviation experts note that all-electric aircraft still have a long way to taxi when it comes to technical considerations like battery energy density.

X-57 electric motor (Source: NASA)

For their part, NASA researchers said development of the X-57 “Maxwell” all-electric aircraft focuses on new battery technologies and the prospect of using less fuel while reducing aircraft emissions. “NASA researchers are looking at ways to improve aircraft, not reinvent them,” program officials note.

NASA Ames Research Center in Mountain View, Calif., is leading modeling and simulation efforts using the space agency’s Pleiades supercomputer. Simulations are creating accurate computer models of aerodynamic performance. Those models will then be incorporated into the X-57 flight simulator, a key tool for aviation research.

Computer modeling will be followed by scale models, wind tunnel tests and prototype flight tests. Test flights will use a modified Tecnam P2006T aircraft, eventually ramping up to test wingtip motors and fabrication of a new wing.

While battery energy density remains a big hurdle to development, NASA researchers note that electric motors can be installed just about anywhere on aircraft to improve efficiency. One version of the X-57 prototype includes 14 battery-powered motors and propellers. A dozen would be used for takeoffs and landings while two wingtip engines would provide propulsion and stability during level flight.

Those motor can’t compete with the horsepower of combustion engines, but they are smaller and lighter.

The current battery configuration includes commercial lithium-ion cells packaged as a pair of 400-pound cells placed in custom-designed battery packs stowed in the cabin. That power plant would supply 23 kilowatt hours of energy, according to NASA’s X-57 Maxwell web site.

X-57 battery pack
(Source: NASA)

Some suspect all-electric airplanes remain, well, pie in the sky. “I love the idea of an electric motor instead of an internal combustion engine,” said veteran pilot and software engineer Gregory Travis. “But I don’t see how they are going to get battery energy density high enough to meaningfully compete with hydrocarbon fuels.”

Instead, a renewable energy approach to aviation should focus on fuel cell approaches, Travis added, not unlike the power supplies that enabled Apollo astronauts to fly to and from the moon. “What we need is a fuel cell that can directly convert liquid hydrocarbons into a meaningful amount of electricity,” Travis asserts.

The X-57’s additional moniker is an homage to James Clerk Maxwell, the 19th century Scottish mathematician and physicist who pioneered the theory of electromagnetism.

Whether or not the experimental plane gets off the ground, the NASA effort could at least help drive battery and other power management innovations in a market segment requiring maximum reliability and safety.

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