Electric aircraft pioneer Bye Aerospace today unveiled plans to enter the mainstream business aviation market with the eFlyer 800, which will be powered by a pair of Safran's new Engineus electric motors. The new model will be able to carry seven passengers and two pilots on flights of up to around 575 miles at speeds of almost 370 mph.
The eFlyer 800 will compete with existing turboprop models such as Textron's Beech King Air 260 and Daher TBM 910, albeit with less than one-third of the range. Denver-based Bye Aerospace indicated it expects to complete type certification over the next four to six years, but said that it already has “customer deposit agreements” from undisclosed air taxi, charter, and cargo operators in the U.S. and Europe.
The company is working toward FAA Part 23 type certification for its two-seat eFlyer 2 model, which will mainly be used for flight training. It is also developing a four-seat eFlyer 4 aircraft that could also be used for air taxi and cargo missions, as well as for more advanced flight training.
Both of these eFlyer models are also powered by the Safran motors, which have a power rating ranging from 50 kW to 500 kW/1 MW. These will be supplied with the French company’s GeneusGrid electric distribution and network protection system.
The eFlyer 800 is expected to feature new lithium-sulfur batteries being developed by UK-based Oxis Energy. Bye is aiming for a recharge time of between 20 and 30 minutes.
According to Oxis, the first-generation of these batteries have a specific energy of 450 Wh/kg and an energy density of 550 Wh/L. The company believes these levels could be boosted to 550 Wh/kg and 700 Wh/L by late 2023, and then to 600 Wh/kg and 900 Wh/L by 2026.
Generally speaking, energy levels of around 400 Wh/kg have been regarded by some as the tipping point for making lithium-ion batteries viable for electric aircraft. Currently, levels of around 220 to 250 Wh/kg are more typical in the sector.
Bye Aerospace claims that operating costs for the eFlyer 800 will be one-fifth of comparable jet-A-powered aircraft, based on the assumption that electricity will cost less than fuel and that electric motors will require less maintenance than turboprop engines. “The eFlyer 800 is the first all-electric propulsion technology airplane that achieves twin-turboprop performance and safety with no carbon dioxide and extremely low operating costs,” said company founder and CEO George Bye. “This type of remarkable economy and performance is made possible by the electric propulsion system and advanced battery cell technology that results in significantly higher energy densities.”
Bye Aerospace did not announce the list price for the eFlyer 800 but indicated to Forbes magazine that it would be similar to that of the King Air 260 at a bit above $6 million.
The new aircraft's maximum payload will be 1,540 pounds and Bye has yet to confirm projected runway takeoff performance. The company says that with its smaller eFlyer prototypes it is recording noise levels that are around 30 dB quieter than comparable piston- or turboprop-powered aircraft.
In March, Textron, which includes the King Air family of aircraft in its portfolio, announced its intention to enter the electric aviation sector. The U.S. group confirmed it has created a new division called Textron eAviation, but declined to provide any details of its plans for this new venture.
In June 2019, France-based Daher announced a partnership with Safran and Airbus to develop a hybrid-electric version of its TBM family of aircraft under the EcoPulse program. This involves adding six Safran electric motors with propellers on the wing, and having these operate in tandem with the aircraft existing Pratt & Whitney PT6A turboprop acting as a generator while also powering a nose-mounted propeller. The partners have been aiming to achieve a first flight in 2022.
Back in November 2020, South Korea’s Aerospace9 group announced a strategic partnership with Bye Aerospace that it said included an undisclosed investment in the U.S. company and a purchase agreement covering 300 aircraft. These included 150 eFlyer 2s, 148 eFlyer 4s, and two examples of a larger new model that at the time was referred to as the Envoy.