NASA is edging seriously close to completion of the agency's first all-electric X-plane: the X-57 Maxwell.
NASA edges closer to its first-ever all-electric X-plane
As of writing, NASA is completing tasks for the X-57's ground testing at the agency's Armstrong Flight Research Center in Edwards, California — with aims toward taxi tests and flight testing, according to a post on NASA's website.
Qualification tests and assembly are in progress on two crucial components of the X-57 vehicle at NASA's primary contractor for the project: Empirical Systems Aerospace (ESAero), out of San Luis Obispo, California.
The new components include a future high-aspect-ratio wing that can fly on the aircraft in X-57's ultimate configuration, and the electric cruise motors — which will power the craft during flight.
Modified from a Tecnam P2006T airplane, the X-57 is as of writing in the first of three configurations as an all-electric aircraft, known as Modification II, or Mod II. This configuration comes with a replacement of the vehicle's standard combustion engine (100-horsepower Rotax 912S engines) with 60-kilowatt electric cruise motors, X-57's test flights while in its Mod-II phase will take to the air with the Tecnam's standard wing.
Mods III and IV: X-57's next phases
The next phase — Mod III — will replace the old with a new high-aspect-ratio wing, significantly reducing the plane's vehicle area — and moving cruise motors out to the wingtips — before the aircraft may fly in its ultimate Mod IV configuration, which will include another 12 smaller high-lift motors placed along the leading edge of its wing, for crisp takeoffs and landings.
A constant throughout these developments, however, is the collection of electric cruise motors. They're already undergoing tests at ESAero to confirm their readiness for installation on the new X-57 aircraft itself.
"All three mods of X-57 will utilize the same cruise motors. We've taken those cruise motors and we're putting them through functionality tests, acceptance tests, and qualification tests to ensure their airworthiness for the X-57 vehicle," said Trevor Foster, ESAero Vice President of Operations, according to NASA. "As part of the NASA airworthiness process, these are the verification and validation steps to reduce risks and increase the safety and reliability of the components on the vehicle."
The next testing steps include high-power and endurance testing for the cruise motors and cruise motor controllers, with an emphasis on monitoring general system efficiency. Engineers will accomplish this using a dynamometer to measure voltage and current, collecting data at a wildly fast pace of two million times per second.
After this, the performance of these components will be recorded, analyzed, and enhanced to optimize the engine's efficiency. High-power testing aims to confirm that the new cruise motors and their controllers will perform everything required on a flight mission — with extra performance capabilities to provide functional overhead, according to NASA.
Endurance testing the all-electric aircraft
However, endurance testing will involve a much broader range of activities, according to Leader of ESAero Cruise Motor Acceptance and Qualification Colin Wilson.
Endurance is key not only for the performance of the X-57 aircraft, but also for transportation at large. Once jet-fuel-burning aircraft engines are replaced by all-electric alternatives — we could see the entire aviation industry decarbonize.
"The endurance testing involves everything from doing small checks and low power checks, making sure that the motor spins and communicates and gives us the information we need, all the way up to running full mission profiles, and even taking it beyond mission profiles, where you're really pushing the limits of temperature and power," said Wilson.
"So far, the motors and controllers have performed exceedingly well, and we're in the process of getting them to perform even better."
The X-57 will always take to the air with a pair of cruise motors in each configuration, but five total motors were built for the project, according to NASA. One was disassembled and used to evaluate the engine unit's construction, with two slated for use as flight motors on the X-57 itself. The final two will see use during envelope expansion testing, and will also serve as spares to the primary flight motors.