Bye Aviation’s eFlyer 800

Can David really slay Goliath? George Bye thinks so. He’s the effervescent aviation entrepreneur who once tried to market a two-seat jet fighter called the Javelin as a business aircraft and now finds himself and his company, Bye Aerospace, on the cutting edge of electric aviation. 

For several years, he has been developing all-electric training single-engine aircraft called the eFlyer 2 and a somewhat larger four-seat variant known as the eFlyer 4. But earlier this year, he set his sights on a potentially bigger market, taking aim at Textron’s venerable King Air business turboprop line with an all-electric fixed-wing alternative: the eFlyer 800, which Bye expects will sell for around $6 million when it enters service in 2025.

The eFlyer 800 will carry seven passengers and one pilot at speeds up to 320 knots and will have a range of 500 nautical miles. It will be powered by a pair of dual-wound Safran Engineus electric motors with battery packs designed to recharge in 20 to 30 minutes. The batteries are divided into four packs, two in the aircraft floor and one in the rear of each electric motor on the wings. The eFlyer 800 can be fitted with safety features including a whole-aircraft parachute, an emergency autoland system, and avionics with flight envelope protection. Envisioned options include solar cells on the wings and in-wheel electric taxi. The maximum payload is 1,540 pounds. The 65-inch-wide cabin is nine inches wider than a King Air 260 cabin and five inches wider than a Pilatus PC-12 cabin. 

While the airframer intends for the 800 to compete with conventional business turboprops, it has decidedly shorter legs, with less than one-third the range of popular jet-A-fueled models such as the King Air 200 and Daher TBM 900 series. But that has not dissuaded customers who understand that the typical business aviation trip in the continental U.S. is 500 miles or less. Aircraft lessor Skye Aviation has ordered 15 of the aircraft. Other announced customers include private flight group Jet It and its European affiliate JetClub and Rheinland Air Service, which is Bye's distributor in Germany, Switzerland, and Austria.

Limited range isn’t the only reason some people remain hesitant about the viability of all-electric aircraft; there have also been safety concerns, especially in light of several recent high-profile fires in prototypes from other manufacturers. This summer, Luminati Aerospace CEO Daniel Preston warned that the risk of fire in electric aircraft has not been adequately addressed. “Automotive battery technology is completely unsuitable for aerospace,” he said, adding, “Power-density-wise, one ton of avgas [fuel] equals 200 tons of the best lithium polymer batteries in the world. Lithium polymer [lipo] batteries are not just worse than petroleum, they are monumentally worse than petroleum. 

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“The only reason people are interested in electric aviation is that the motors have incredible power densities,” Preston continued. “A piston engine is half a horsepower per pound and with a turbine, you can be one to two horsepower per pound. On our electric motors, we are at 12 horsepower per pound. So, the first rule in aerospace is that even bricks fly with enough power. Electric motors can make anything fly."

But George Bye insists that eFlyer technology mitigates this risk. According to him, there is a high degree of safety redundancy between the two battery packs with a power management system determining available power levels. "This [the eFlyer 800] is literally a four-motor airplane with two props and a fourfold electric storage system," Bye explains. "The key thing here is that this is a three-hour airplane. It’s a thoughtful integration of a whole [system] as opposed to just chucking in batteries of a certain technology—sophisticated yet simple and redundant systems integrated into a structure that is incredibly sleek. This has a lift-over-drag ratio of about 20 to one.” 

eFlyer 800

Bye says the aircraft would use a proprietary design for the battery packs and thermal management system. “The secret sauce is how the cell is packed, the thermal management, and how you maintain safety. The decision-makers and the FAA want to know how you maintain safety,” he says, adding that “every single battery cell is monitored—full time. Any bad player [cell] is taken out.” Bye notes that the company had been flying such a thermal management system on its prototype eFlyer 2 for over five years. 

The potential advantages of electric aircraft are myriad, not just in terms of reduced atmospheric and noise emissions but also regarding maintenance and recharging. George Bye expects the electric motor on the eFlyer 2 to last 10,000 hours—“longer than the airplane,” he says—and the battery pack up to 1,500 cycles. Battery pack charging time should be 15 to 20 minutes with a supercharger. Direct hourly operating costs on the eFlyer 4 could be as little as $20. Bye says the direct hourly operating costs on the larger 800 will be 80 percent less than the same figure for a comparable turboprop, or around $200. These are the types of metrics bandied about when people discuss disruptive technologies. 

And other manufacturers have taken notice. Airbus recently announced it has begun flying an experimental helicopter with an electric backup motor that will give pilots time to land safely in the event of a main engine failure. In March, Textron—parent of brands Cessna, Beechcraft, and Bell—announced that it was forming an “eAviation” division to “take advantage of our fixed-wing and rotorcraft expertise in emerging technologies.” Other companies, including United Technologies and France’s Safran, are studying all-electric or hybrid aviation propulsion, and more than 200 electric vertical takeoff and landing (eVTOL) air taxi designs are in various stages of maturation.

For business aircraft, the eFlyer could prove every bit as disruptive as when Cessna introduced its Citation line in 1968. George Bye is counting on it. And he may be right. 

2025 Bye Aerospace eFlyer 800 at a Glance

Price:
$6 million (est.)

Range:
500 nm 

Maximum cruising speed: 
320 kt 

Pilots:
1–2

Passengers:
6–7

Cabin dimensions: 
65 in (W) x 55 in (H) (preliminary)

Ceiling:
35,000 ft

To learn more about electric aircraft, visit FutureFlight.aero, a news and information resource developed by BJT parent company AIN to provide objective, independent coverage and analysis of cutting-edge aviation technology.