Sun Flyer 2 to be Powered by Siemens Motor

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

George Bye has been enjoying a year filled with great expectations (and accomplishments).  With 121 deposits on the Bye Aerospace Sun Flyer 2 from seven countries, the training aircraft needs only two things to make dreams come true for a large number of people – a motor and FAA certification.

Siemens Steps In

In a joint press release, Bye, CEO of Bye Aerospace, announced a partnership with Siemens that will see the German firm “collaborate on future development of Bye Aerospace’s Sun Flyer 2.”

L-to-R: Olaf Otto, Siemens Head of eAircraft Sales and Business Development; and George Bye, Bye-Aerospace CEO. flanked by Siemens small aircraft motors

Bye explained, “We are pleased to announce an agreement with Siemens to provide the electric propulsion motor and inverter for the Sun Flyer program.  They will be an active partner through the FAA certification and production phase for the Sun Flyer 2.”

Siemens will supply the two-seater with its SP70D motor with a peak output of 90 kilowatts (115 hp.) and a continuous rating of 70 kW (90 hp.).  Bye explained the nice “fit” with the Sun Flyer 2.   “Given its performance and form factor, the SP70D motor is perfect for Sun Flyer.  Members of the Siemens team have already been participating in development and certification meetings with the FAA, and we will be making future announcements about progress with the Sun Flyer 2’s flight test program.”

Dr. Frank Anton, Executive Vice President and Head of eAircraft for Siemens, added, “The Siemens SP70D motor has been specifically designed for the needs of 2-seater flight trainers.  We know that safety, performance and cost of electric propulsion in the flight training market will be game changing and we are proud to partner on the Sun Flyer family of aircraft.”


Bye Aerospace claims that their trainer will have a total operating cost of $14.00 per hour (compared to $88.31/hour for a Cessna 172).  Even better, the coming four-seat Sun Flyer 4 will feature $19.80 total operating costs per hour (Compared to $122/hour for a Cessna 182).  These low operating costs and minimal maintenance costs, compared to piston-engine alternatives, might breathe new life into a moribund pilot training market.

Siemens is a huge international business with $92 billion in revenues last year.  This level of backing will be a welcome change in the usually cash-strapped world of private aviation.  Siemens has grand plans for its electric aircraft motors, though, including powering Uber’s sky taxis and large-scale regional airliners.  See this presentation for an overview of Siemens’ far-ranging efforts in electric aviation.

A Sad Note

As a counterpoint to this encouraging news, a Siemens-powered Magnus eFusion crashed in its native Hungary, killing its two occupants.  One report indicated a fire had occurred before the craft crashed and burned.

Siemens motor in Magnus eFusion at Friedrichafen

HA-XEF was on display at this year’s Aero Expo at Friedrichshafen, Germany.  We will report on this story as accident reports become available.

We offer condolences to the associates, friends, and family of the pilots.

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