The United States’ National Aeronautics and Space Administration, better known as NASA, is set to start testing of its first all-electric X-plane, the X-57 Maxwell, which now moves from the component design and prototype phase to operation as an integrated aircraft.
NASA’s X-57 Maxwell will begin high-voltage functional ground testing at its Armstrong Flight Research Center in Edwards, California, a process which will not only begin putting the aircraft through real-world stresses, but which will also begin to help develop certification standards for emerging electric aircraft.
The ground testing is also a critical step towards taxi tests and eventual first flight.
“Many of the team members operating this test will be the same ones who will be sitting in the control room for flight, and that’s why I’m excited,” said Sean Clarke, NASA’s X-57 principal investigator.
“We’ve turned a corner from system design and lab tests, to turning it over to the NASA flight systems and operations engineers to actually operate the vehicle. What they’re learning in this test, they’ll take with them into the control room for first flight.”
The X-57 Maxwell is currently in its first configuration as an electric aircraft, labelled Mod 2, and while its battery control system nears completion it will use a battery support system for this phase of testing, drawing power from a large and high-voltage power supply.
Though Mod 2 looks like a plane, it does not resemble NASA’s final design for the X-57 Maxwell, with at least four iterations planned by the Armstrong Flight Research Center.
First off the blocks for the X-57 is a low power assessment of its startup and shutdown sequences, as well as verifying that the new motor control software boots up and controls the motors as expected.
The final iteration of the X-57, Modification IV, will boast 12 high-lift motors along the leading edge of the distributed electric propulsion wing.
The high-lift motors are designed to get the X-57 airborne, but when the plane levels out for cruise mode they will then deactivate, the blades of each motor will stop rotating, and they will fold into the nacelles so as not to create unwanted drag during cruise. Two wingtip cruise motors will maintain flight at cruising altitude.
Additional testing will include higher-power operation of the vehicle, starting with testing of the first pair of electric cruise motors to fly on the X-57, which will be powered up and activated so as to allow the engineers to ensure that the vehicle’s propellers spin as designed.
This will be followed by throttling the motors up to make sure they provide the necessary power, validating the vehicle’s instrumentation system, and verifying whether all the sensors installed across the aircraft are functional.
This high-voltage testing will then feed directly into final verification and validation testing, one of the final steps before taxi tests can begin.