VoltAero continues working towards a maiden sortie of its initial Cassio 330 prototype but supply chain issues have pushed back the milestone by around six months.
However, the French start-up insists the delay will not force it to shift its 2025 service-entry target for the five-seat hybrid-electric aircraft.
Speaking to FlightGlobal at the NBAA business aviation show in Las Vegas, where a mock-up of the Cassio 330 was prominently displayed in the entrance hall, chief executive Jean Botti said VoltAero now expects to fly the aircraft by mid-2024, a delay of around six months from its previous end-2023 goal.
Supply chain issues, particularly relating to the availability of aluminium for the aircraft’s fuselage, have forced rescheduling, says Botti: “The supply chain is an issue for us like everybody.”
But Botti remains confident that there will not be knock-on delays: “We are still marching for certification in 2025,” he says.
Botti’s conviction stems from VoltAero’s plans for flight testing. The initial prototype will be used to validate the aircraft’s configuration and new Duc Helices-supplied propeller and will run solely on its Kawasaki thermal engine.
“The first bird will not have batteries or electric motors on board,” he says.
Additionally, the test asset – to be known as the Cassio 21 – will fly as an experimental aircraft under the supervision of French regulator DGAC rather than certification authority the European Union Aviation Safety Agency (EASA).
In the meantime, programme partner Akira will validate the full hybrid-electric powertrain though a series of ground tests, enabling the flight of a second prototype equipped with that propulsion system in the second half of next year.
That aircraft’s arrival will effectively kick-off the flight-test portion of the EASA certification campaign.
“This is what we thought would be the best way to speed up the process,” says Botti. “What seems to be a delay is no impact for us.”
A critical design review should be completed by April 2024, he adds.
VoltAero’s hybrid-electric module combines the Kawasaki four-cylinder thermal engine, a Safran EngineUs 100 electric motor and a gearbox from French transmission specialist Akira. Batteries are supplied by US firm Electric Power Systems.
Taxi, take-off, climb and landing are performed solely using electric power, while the thermal engine serves as a range extender, recharging the batteries during cruise. It also provides a back-up in case of an electrical system failure.
A follow-on aircraft, the Cassio 480, will use the same fuselage as the initial production aircraft but will use a high-power, six-cylinder Kawasaki engine and will be able to accommodate five passengers and a single pilot.
First flight of the Cassio is scheduled for 2026 and will be approved as an evolution of the baseline model via a supplemental type certificate. A third member of the family, the Cassio 600, should make its test debut in 2028.
However, Botti is not ready to disclose what the Cassio 600 will look like. “What we can say is that the 600 will build on all the elements developed for the 330 and 480,” he says. ”It’s an aircraft that will look almost the same but will not be the same.”
Backlog across the Cassio family stands at around 220 commitments and Botti says that figure may soon increase: “There is nothing we can announce yet, but we are closing on an important [firm order],” he adds.
Future developments include investigating the potential for the Cassio family to use liquid hydrogen as the energy source for the thermal engine. Flights using the fuel will be performed by the Cassio 21 testbed in the second half of the decade.
Meanwhile, a Series B funding round is set to end this year with VoltAero’s target to raise €32 million ($33.8 million).
