VoltAero Flight Tests Hybrid-Electric Cassio

French airplane maker VoltAero has begun flight testing on a hybrid-electric-powered airplane series called Cassio. The Cassio 1 testbed is powered by two electric motors, mounted on the wings, and two piston engines—a pusher and a puller—on the fuselage. The testbed looks like a Cessna 337 Skymaster and has a seating configuration for six people. VoltAero plans to produce a Cassio product line ranging from four to nine seats.

“The current test phase is with the powertrain for our six-seat Cassio version, to be followed by validation of the final aerodynamic and powertrain configurations on both the four- and nine-seat Cassio versions,” said Jean Botti, VoltAero’s CEO and chief technical officer. The flight testing is conducted out of the Royan-Médis Aérodrome, near Royan on the west coast of France.

The two wing-mounted ENGINeUS 45 electric motors were designed by Safran Electrical & Power. The company, which is a part of France’s Safran group, has its roots in Labinal Power Systems, which has been involved in aircraft electronics manufacturing for decades.

“Flying on the power of Safran’s ENGINeUS motors is truly remarkable, with no vibration and extremely low noise levels,” said VoltAero’s test pilot and technical director Didier Esteyne. “It confirms that our Cassio aircraft will bring an entirely new experience to aviation.”

The piston engines on the testbed are there for safety purposes only, and the front engine will eventually be removed. After approximately 20 hours of flight testing in this configuration, the company plans to replace the rear engine with its proprietary hybrid-electric power module. The power module, which is currently in development, will consist of a 370-hp internal combustion engine and three 60-kW electric motors. In addition to producing propulsion, the power module will recharge the batteries on the electric motors.

Production versions of the Cassio series are expected to fly 3.5 to 5 hours. The nine-seat Cassio version is expected to produce nearly 800 hp and fly faster than 200 knots, the company says. VoltAero hopes to start delivering its Cassio airplanes “during the 2021-2022 timeframe,” a highly ambitious target considering the stringent process of aircraft certification.