Bye Aerospace says it is advancing work on electrically-powered eFlyer 2 flight training airplane it has had in development since 2021. During the EAA AirVenture show last week, the company’s president and CEO, Rod Zastrow, told AIN it is focusing efforts and investment on the two seater and the four-seat eFlyer 4 model, with earlier plans for the nine-passenger eFlyer 800 now on hold.
At the event in Oskhosh, Wisconsin, Bye Aerospace displayed a mockup of the eFlyer 2. This model matches the aerodynamic shape of the eventual production airplane but is not intended to be a flying prototype.
Parts used to make the mockup “are representative but not conforming,” according to Zastrow. They were manufactured by the Bye team at its Denver headquarters using eFlyer production tools and molds.
Plans call for first flight of a largely production-conforming prototype in nine to 12 months, followed by FAA Part 23 certification in another 24 months. According to Zastrow, the company holds more than $700 million worth of orders for 1,024 two-seat eFlyer 2 and four-seat eFlyer 4 airplanes, with about 50% of those secured by nonrefundable deposits and the remainder by letters of intent.
Zastrow said he has had a long association with Bye Aerospace, having become an early deposit-holder and bringing Spartan School of Aeronautics in as launch customer for the eFlyer 2 and joining the Bye board of directors five years ago. In April 2024, he became president and CEO.
“We had kind of stalled in 2022, and so I was asked to help focus on the first product and execute our certification game plan,” he told AIN. Last year, the company’s CFO, James Dunn, acknowledged that “an extraordinarily challenging funding environment” had slowed progress in getting the aircraft to market.
In 2021, Bye Aerospace had said that it was already assembling the fuselage for the first serial product eFlyer 2, although that work had been contracted to another company. In November 2020, Bye Aerospace projected that FAA certification of the eFlyer 2 would take place by the end of 2022, although in 2019, the company aimed to complete certification of the eFlyer 2 in 2021. The larger four-seat eFlyer 4 model was due to make a first flight in early 2021.
eFlyer 800 Planned As King Air Replacement
In April 2021, Bye Aerospace announced plans to develop the twin-propulsion-system electric eFlyer 800, which would compete with traditional designs such as the Beechcraft King Air, flying nine people up to 500 nm. “We continually look to design and potentially introduce new, disruptive technologies,” Zastrow said. “We are currently focused on the eFlyer 2 for initial type certification and its highly common derivative, the four-seat eFlyer 4.”
The eFlyer 2 will be powered by a 100-kW Safran EngineUs 100 B-1 electric motor, which received EASA certification earlier this year. FAA validation is pending. Avionics will be by Garmin and include the G500 TXi touchscreen display.
Batteries will be installed in the fuselage, with two-thirds of them behind the cockpit and one-third in the forward fuselage. “Cooling is an important consideration both in the air [heat-generating discharge, especially during takeoff and sustained climb phases of flight] and during rapid ground charging,” Zastrow explained. “Each battery and aircraft combination will have different cooling needs. So, some may need cooling just on the ground, some may need it both on the ground and in the air, and some not at all.”
In any case, the battery manufacturer has not been selected yet. Bye Aerospace said it is waiting for battery technology to mature before making a commitment as to which cells to use for the production aircraft.
3-Hour Endurance, 200 nm Range
Flight controls are conventional cables and pushrods, and the design is spin-resistant and will be equipped with a whole-airplane parachute. Performance projections for the eFlyer 2 include 135-knot top speed, rate of climb of 1,000 fpm, 3-hour endurance, and range of more than 220 nm. Target maximum takeoff weight is 2,450 pounds.
There are 25 full-time and consulting personnel working for Bye Aerospace, according to Zastrow, and more will be added as prototype construction continues and certification activities pick up steam. “We have a number of highly experienced design engineers and manufacturing personnel who have extensive FAA type certification experience that, in aggregate, represent approximately 20 successful FAA type certification programs,” he said.
Nearly 100 structural parts have been manufactured so far, including the horizontal stabilizer and most of the 38-foot wing, except for skins. “The most important piece,” he said, “being the main wing spar, which is a 186-ply [piece], all-composite.” Structural components are cured in Bye Aerospace’s 40-foot composite curing oven.
To reduce the amount of touch labor required to build composite parts (the eFlyer 2 has about 225 structural parts), Bye Aerospace is working with companies that include Elevation Aero, Siemens (material flow planning software), materials manufacturer Toray, component partner M4 Engineering, and others. “We plan to match our workforce resources with the project needs to ensure quality and efficiency,” he said.
Bye Aerospace expects to employ up to 2,000 people once full-rate production begins, and the company is exploring various locales for its factory. “Workforce is the number one criteria as we look for a rate manufacturing site,” he said.
While Bye Aerospace is a private company and doesn’t share financial information, Zastrow concluded, “We are enthused about the growing momentum we see from current and prospective investors, which is indicative of our ability to launch our full-scale prototype production. We are cautiously optimistic about our future across the fields of design, engineering, partnerships, sales, and funding. Our goal is to get this design into the air.”