Ascendance expects to complete the assembly of the first full-scale prototype of its Atea hybrid-electric VTOL aircraft by early 2026. This model will feature the latest iteration of the French start-up’s Sterna propulsion system, which has been refined over the past two years with extensive evaluation on an iron bird testbed.
Last month, the Toulouse-based company was boosted by a new partnership with aerospace giant Airbus, which will support its efforts to bring hybrid-electric powertrains into commercial services, potentially on other platforms. It is also involved in a new alliance with Daher, Safran, and Collins Aerospace to develop hybrid-electric propulsion for general aviation aircraft.
During the recent Paris Air Show, the company launched the Sterna Hybrid Pack, which encompasses a hybrid core unit plus an energy management system and battery packs. This technology is being offered to other aircraft developers through an initiative that is now backed by leasing group Green Aerolease as well as regional aircraft operator Finistair and helicopter group Leman Aviation.
The Ascendance team has been working on the Atea program since 2018 and has adapted the propulsion system over time. “The first thing we learned was that attaching batteries directly to a turbine didn’t work, so we realised we needed to have a complete power distribution and management system, including a controller, so we’ve spent the past five years developing Sterna,” explained Thibault Baldivia, the company’s chief commercial officer.
The Sterna propulsion system combines a turbogenerator supplied by Turbotech with Safran’s electric motors. Another French company, Exoes, is providing the thermal management system, as well as the batteries, which provide power during the takeoff and climb phases of flight.
Atea’s architecture features eight ducted fans installed in the wing and canard to provide vertical lift, plus propellers for horizontal flight in the nose and tail. The company first tested these in a wind tunnel and then produced full-scale prototypes installed in a forward wing section for testing.
Replacing Helicopters with Lower Costs
According to Baldivia, he and his colleagues have closely involved prospective customers in the design process for Atea to take into account a variety of passenger, cargo, and utility applications that could include emergency medical flights. To date, it has signed letters of intent covering 617 pre-orders, with much of the early interest coming from rotorcraft operators such as HeliFirst and Jet Systems Helicoptères Services, as well as from Evfly, Yugo, Philjets, and Flyshare.
With four passengers on board, Atea’s projected range is around 217 nm, and Ascendance is now anticipating a higher-than-expected cruise speed of 130 knots. “That’s not far off what a helicopter can do,” said Baldivia, underlining expectations that the VTOL vehicle will deliver reductions in fuel burn of 80% compared with comparable rotorcraft, such as the Airbus H130, and 50% lower direct operating costs.
Seven years into its quest, Ascendance has retained the support of early investors, who included members of the Dassault family. Its advisory board is packed with former senior Airbus executives, and it has also attracted financial support under the government’s France 2030 program.