Later this year, the X-57 Maxwell, a small experimental plane powered solely by electricity, will hopefully take to the skies. The latest in a long line of NASA X-planes, or experimental aircraft, the X-57’s demonstration will be used to prove that the craft’s unique design works.
Dubbed “Maxwell” in reference to the 19th-century physicist James Clerk Maxwell, the craft was adapted from a modified gas-powered Italian Tecnam P2006T, a small general aircraft that typically holds four seats.
“What’s really exciting about electric propulsion technology is it gives aircraft designers so many new and interesting tools that we can use to make aircraft do interesting things and do them more efficiently,” says Sean Clarke, principal investigator for the project at NASA’s Armstrong Flight Research Center.
Although the aircraft won’t ever be in production, industry experts are keen to see the kind of results the plane’s technology will produce. Here’s what we know about how X-57 works, and how its initial flight—NASA is targeting early summer of this year—could benefit the aviation industry.
How does it work?
Unlike a typical commercial aircraft, NASA’s tiny two-seater model doesn’t rely on fuel tanks holding a petroleum product. Instead, the X-57 uses rechargeable lithium-ion batteries to power the motors and propellers that pull the craft through the air. Weighing in at about 3,000 lbs, one of the plane’s most notable features is a smaller, sleeker wing than previous iterations of the craft had. Although it essentially has the same wingspan of a regular Tecnam, the front-to-back length of the aircraft is much smaller—about 40 percent less area than the original.
And instead of the two traditional engines the original model utilized, X-57’s wing has been outfitted with 14 electric motors. The 12 smaller propellers across the wing help the plane achieve lift, and a larger one at the end of each wing provides forward thrust, helping the craft to cruise. It’s one special feature that allows the aircraft to excel at high-speed flight.
“Having the two motors at the wingtips, and then 12 smaller ones spread out along the wing, was kind of a good trade off between having the best performing wing effects versus having a much more complex electrical distribution system,” says Clarke.
These motors are easy to build, but unlike gas-powered engines, they use complex software, or advanced motor controllers, to drive them. The electrical power requirements for the craft are also similar to what’s needed to operate an eVTOL, or electric vertical take off and landing aircraft.
But Clarke, who has been involved with the project since 2015, says that NASA is currently more focused on improving aircraft efficiency rather than targeting new takeoff features. The X-57 will take off and land from runways the way a typical small aircraft does.
Down the road, one of the most exciting applications for those in the electric aviation field is how it could advance regional air mobility, says Clarke. With mainstream electric vehicles, passenger or cargo trips that would take several hours via the highway could be halved. And along with reducing transportation and maintenance costs, it could provide a huge market for emerging air taxi services.
“These same technologies could really increase the availability of transportation, especially in urban areas,” says Clarke. “If we can show that this is reliable enough for aircraft designers to make commercial aircraft based on these technologies, it could have a huge impact on the availability of aviation for the public.”
Inside the Armstrong Flight Research Center located in Edwards, California, NASA test pilots and engineers have worked together for years to develop a fully featured cockpit simulator to prepare pilots to fly the X-57. According to Clarke, their performance often informs the project’s next steps.
“Our pilots do a lot of work in our simulator to help us understand not only if they have all the data they need while they’re flying,” he says. “But also so they can give us feedback so that we can change the design to make it more appropriate for what a pilot needs in order to operate these systems.”
With a range of about 100 miles, the X-57 Maxwell will reach a critical take-off speed of 58 knots—or 67 mph—and should be able to operate at a maximum altitude of 14,000 ft. At takeoff, the craft uses 250 kilowatts of power. During cruising, that number slowly decreases, before steadying at about 80 kilowatts.
Because X-57 is powered by electricity and renewable energy, it could meet its goal of reaching zero carbon emissions during flight, as well as reducing overhead flight noise. Compared to general aircraft, renewable energy is cleaner, cheaper, and overall, better for the environment.
Marty Bradley, a professor of aerospace engineering at University of Southern California Viterbi, says that advances in electric aviation also puts pressure on finding long-term solutions to keeping better track of our environmental footprint. Although electric vehicles like X-57 are gaining ground, Bradley predicts that similar to the way we have hybrid cars—which are powered by both combustion engines and electric motors—the advent of hybrid planes isn’t too far off.
“It’s become increasingly important for aviation to be sustainable,” He says. “It’s to minimize its environmental impact while still maintaining the benefits of being able to transport people and cargo quickly, right around the world.”