Looking every bit like a winged tube of toothpaste, NASA’s X-57 Maxwell experimental plane sits in a hanger at Edwards Air Force Base in California. The is NASA’s first crewed experimental plane in 20 years; it runs solely on electric power, an agency first, and it’s about to undergo high-voltage functional testing in advance of its first flight, scheduled for later this year.
“Currently, we have a battery emulator that we’re using to provide power to the aircraft,” said Nick Borer, an aerospace engineer at NASA’s Langley Research Centre, in a video call. “But this is the first time we’ve had the low-voltage and high-voltage systems operating together.”
NASA’s compendium of experimental aircraft, or X-planes, speaks to the agency’s long history of sussing out the future of flight. They range from kite-shaped, Bush-era combat drones to the Eisenhower administration’s autogyro, which sounds like a Greek dish that eats itself but looks more like a tricked-out tricycle combined with a helicopter. The new electric craft certainly looks more like a plane than any of them, and it has 14 propellers.
The X-57’s hallmark features include its exclusively electric fuel system and 14 motors — six smaller ones along either wing and two larger motors at the tips, which would have been difficult to manage with hefty, gas-powered engines in their place. (The idea of wingtip motors was floated as early as the 1980s, but technological limitations of the time relegated such ideas to the realm of futurism). The fuselage is a recycled husk from a Tecnam P2006T, a high-winged Italian twin-engine plane. The project’s primary contractor is California-based company Empirical Systems Aerospace.
Borer is an aerospace engineer who works on aircraft conceptual design for NASA, focusing on how plane design changes with respect to technological advancements. Since humans learned how to fly, Borer said, just one propulsion revolution had occurred: the shift from piston engines to jet engines for powering flight. The X-57 flips the script for the 21st century, running on two lithium battery packs in the plane’s cabin.
“One of the really cool things about X-57 is that it’s like two and a half, maybe even three X-planes in one,” Borer said, adding that the craft’s final phase — “Mod IV” — would introduce a “fundamentally different way to how you integrate propulsion to an aeroplane. It’s not just putting a motor or battery on a plane; it changes how you design the plane.”
The upcoming ground voltage tests will check the motors’ capacity to run in tandem. The tests will occur without the plane moving and come in advance of taxi tests and, later in 2021, crewed flight. Besides takeoff, which will undoubtedly be cool, Borer is really excited to see the plane land for the first time and get feedback on how the X-57 team handles differently from other planes.
“The way we’ve set it up is that the aircraft modulates and really helps control that critical region in the back side of the power curve,” Borer said, referring to a tricky situation in which propeller aircraft find themselves needing significantly more power as they slow for landing. “My feeling is that it’ll feel like it’s gone, and that’d be a huge advance and an interesting thing to get the test pilots’ opinion on.”
Borer said that an entirely electric plane could be a watershed moment for human flight. The X-57 Maxwell could be “a tide that raises all the boats,” he said. “Or all the aeroplanes.”