GE Aerospace, in a partnership with NASA and Boeing, has begun preparing to fly a hybrid-electric propulsion system on board an aircraft testbed later this decade. The effort follows successful completion for the first time of testing involving a megawatt-class, multi-kilovolt hybrid-electric propulsion system in simulated altitude conditions for single-aisle commercial flight.
Beginning a little more than a year ago and running through earlier this year at NASA’s Electric Aircraft Testbed (NEAT) facility in Sandusky, Ohio, the test marked the culmination of more than a decade’s worth of research and marks a key milestone in the effort to bring hybrid-electric propulsion to single-aisle aircraft in the mid-2030s.
Involving a complete high-power, high-voltage system, including electric motor/generators, power converters, power transmission, and power control systems, the test demonstrated the performance and operation of components in flight environments up to 45,000 feet. Two sets of a hybrid-electric system were operated to represent the right and left aircraft engines.
The components were tested independently and as an integrated system with evaluations covering multiple modes, including power transfer from side to side, power assist to a simulated engine, and aircraft power generation. The trials also involve simulation of energy storage.
Mohamed Ali, v-p and general manager of engineering for GE Aerospace, noted the test managed to overcome a key barrier for use of hybrid-electric in regional and single-aisle aircraft—flight above 10,000 feet with higher voltages. At higher altitudes, plasma arcing becomes an issue when involving high-voltage systems, due to the thinner air causing reduced resistance. “You need to invent technology to prevent that,” he said, as well as handle thermal management.
Ali called the effort a building block toward hybrid-electric and said it is one of many ahead in the journey toward hybrid in commercial flight.
Testing will continue under NASA’s Electrified Powertrain Flight Demonstration program with a flight test later in the decade of a hybrid-electric system involving CT7-turboprop-powered Saab 340 aircraft.
Brian Yutko, v-p and chief engineer of sustainability and future mobility at Boeing, said the company has acquired the aircraft and begun modifications. Boeing unit Aurora Flight Sciences works with Boeing on the integration. The teams are preparing the systems for flight and will prove flight worthiness and safety for the experimental flight tests.