Premium charter operator JetSuite has committed to become the launch operator for a Boeing-backed, hybrid-electric aircraft now in development by Seattle-based start-up Zunum Aero.
A memorandum of understanding announced on 21 May commits JetSuite to order up to 100 of the six- to 12-seat commuter aircraft once they become certificated by the US Federal Aviation Administration.
The launch commitment demonstrates growing commercial airline demand for alternatives to conventional, gas-powered aircraft on short routes. In addition to Boeing’s financial support, Zunum also is backed by JetBlue Technology Ventures. Alex Wilcox, founder of JetSuite, also was a founding executive for JetBlue in 1999.
JetSuite’s commitment also follows a move by European low-cost carrier EasyJet last September to team up with US start-up Wright Electric to collaborate on the latter’s proposal to develop a large, electric-powered passenger jet within a decade.
By contrast, Zunum Aero’s approach seems far less aggressive. The company plans to begin flight tests in mid-2019 with a flying testbed for the six to 12-seater, says chief executive Ashish Kumar. The twin-engined testbed will be converted to a hybrid-electric powerplant gradually, beginning with one electric motor replacing one of the aircraft’s gas-powered engines. Both engines eventually will be replaced with electric motors powered by electricity generated by a 1,450shp-class turboshaft engine.
By the early 2020s, Zunum plans to start producing a certificated aircraft with a 1MW-class propulsion system, putting it in roughly the same size class as a Pilatus PC-9 or Cessna Denali. But the still-unnamed Zunum aircraft should be far more fuel efficient. Kumar says that Zunum is targeting a cost per available seat-mile around the same as a 70-seat Bombardier Q400.
Zunum also has proposed to deliver a 4MW-class, hybrid-electric airliner with about 50 seats before 2030. Such a vehicle poses several major technical obstacles, including the transmissions cables. The 1MW-class aircraft can use existing 540V cables to transmit electricity from the turbo-generator to the motors. A 4MW-class aircraft, however, could need cables with voltages of 1,000 to 2,000V, which may be susceptible at high altitude to a disabling condition known as the Corona effect. Zunum is working on solutions to resolve that problem for the 50-seater, Kumar says.
Meanwhile, work continues on freezing the configuration for the six- to 12-seat aircraft. Later this summer, Zunum plans to select a supplier for the turbogenerator, with Honeywell, GE Aviation, Rolls-Royce and Safran Aircraft Engines among the candidates, Kumar says.