Safran Motors To Power VoltAero’s Hybrid-Electric Cassio 330

Cassio 330
VoltAero will build aerodynamic and propulsion prototypes of the hybrid-electric Cassio 330.
Credit: VoltAero

LONDON—Safran has signed on to supply electric motors for prototypes of French startup VoltAero’s Cassio 330 hybrid-electric general aviation aircraft.

The company’s EngineUS 100 motor will be combined with an internal combustion engine in an integrated parallel-hybrid propulsion system.

The prototypes will be follow-ons to VoltAero’s Cassio 1 propulsion testbed, a modified Cessna 337 Skymaster, which the company had planned to fly at Farnborough. But a technical malfunction with the demonstrator’s prototype hybrid-electric power unit prevented the aircraft being flown to the UK.

VoltAero plans to build two prototypes of the Cassio 330, designated the Cassio 21 and 22. First to fly, the Cassio 21 will be powered by a conventional certified piston engine and will be used to validate the airframe and aerodynamics of the clean-sheet Cassio 330.

Assembly of the Cassio 21 will start in November, with the initial flight targeted by the end of the first quarter of 2023. While this aircraft is being flight tested, VoltAero will be conducting endurance bench testing of its hybrid propulsion unit (HPU). “When the system is ready, it will go into the Cassio 22,” CEO Jean Botti says.

The Cassio 22 is planned to fly in the first half of 2023. Together the two prototypes will be used to certify the Cassio 330, which VoltAero aims to have ready for production in 2024.

After completing flight envelope expansion for the initial four/five-seat, 300-kW Cassio 330, VoltAero will then modify the Cassio 21 with the 480-kW HPU intended for the follow-on six-seat Cassio 480.

This is an incremental development approach similar to that taken by VoltAero with the Cassio 1 propulsion testbed. First flown in 2020, the aircraft is now testing the full 600-kW hybrid propulsion system planned for the largest member of the aircraft family, the 10/12-seat Cassio 600.

The Cassio 1 is also being used to test an airborne data collection and computing system developed by Thales. The FlytLink Edge Computing system is an ultracompact processor, connected to the cloud, that enable real-time collection and transmission of data from onboard sensors and avionics.

Where the Cassio 1 has a pair of 45-kW Safran EngineUS 45 electric motors mounted on the wing, the Cassio 330 will have a single 150-kW EngineUS 100 motor integrated with a 150-kW thermal engine and driving a pusher propeller. VoltAero has two different thermal engines on bench test, Botti says.

The startup has an “a la carte” approach to hybrid propulsion. The Cassio 330 takes off on thermal and electric power, with the EngineUS motor producing 180 kW for a short period for a combined output of 330 kW. The aircraft can then cruise on electric power only for a range of up to 100 nm, or use the thermal engine as a range extender and fly up to 650 nm.

“There is plenty of power in flight to use both—hybrid or pure electric,” Botti says. The propulsion mix can be optimized for economy, but if the pilot wants performance, the aircraft can cruise on both power sources. Maximum power is limited to 265 kW by the propeller, he says.

Where the Cassio 330 has one EngineUS 100 motor integrated with the thermal engine to drive a single propeller, the 480 will have two and the 660 three. VoltAero has selected U.S. startup Electric Power Systems to supply the battery system, which will be integrated into the wing.

Airframes for the Cassio 21 and 22 prototypes are being supplied by Italy’s Tesi Technologia. As the fuselage for both four- and six-seat versions is the same, after completing testing for the Cassio 330 the Cassio 21 will be fitted with a longer wing and foreplane and become a prototype for the Cassio 480.

VoltAero is now in a Series B fundraising round, seeking funding to match up to €13 million ($13.5 million) provided under Europe’s Green Deal Strategy and Recovery Plan. The company is building a production facility in Rochefort, southwest France.

The startup plans to produce aircraft for sale in Europe, the Middle East and Africa, but will license manufacture in the U.S. and Asia, Botti says, adding VoltAero has letters of intent for more than 70 aircraft from five customers in the U.S., UK, France and the Netherlands.

Graham Warwick

Graham leads Aviation Week's coverage of technology, focusing on engineering and technology across the aerospace industry, with a special focus on identifying technologies of strategic importance to aviation, aerospace and defense.