VoltAero flies Cassio with new hybrid-electric power

VoltAero has flown its demonstrator Cassio aircraft fitted with the French company’s hybrid-electric power module for the first time.

The power module is installed in the rear of the demo aircraft, based on a Cessna 337, in the ‘pusher’ position.

Cassio 1 made its maiden flight equipped with the power module on Sunday, 11 October, from VoltAero’s Royan-Médis Airport home base in southwest France. This was followed by two more flight evaluations on different days.

VoltAero power module
A computer-generated image of VoltAero’s new hybrid-electric power module, with three electric motors. Images: VoltAero

The hybrid-electric power module combines three 60kW high-performance electric motors, arranged in a triangular configuratio, with a 370hp internal combustion engine.

This is the configuration intended to be fitted to VoltAero’s largest production Cassio aircraft version, the 10-seat Cassio 600. The plan is to deliver a total hybrid-electric power of 600kW (800hp), giving a 200kt cruise speed.

“The startup of power module flight testing represents a true milestone for hybrid-electric aviation, and it keeps us on track toward our goal of having initial Cassio production aircraft entering service during late 2022 or early 2023,” said Jean Botti, VoltAero’s CEO and Chief Technology Officer.

In regular operation, the power module’s electric motors will be used for low-noise takeoffs and landings, with the internal combustion engine serving as a range extender and for recharging the Cassio’s batteries while aloft.

VoltAero’s series/parallel hybrid power module can operate in modes from full electric to full hybrid, depending on the mission profile and range requirement.

Both the electric motors and internal combustion engine are linked to a common shaft that drives a five-blade pusher propeller. That means each can operate independently with one source acting as a backup in case of a problem or failure of the other.

VoltAero’s aft-mounted hybrid power module and the forward-facing electric motors undergo a ground static run at VoltAero’s Royan-Médis Airport headquarters

VoltAero Technical Director and test pilot Didier Esteyne flew Cassio 1 for the flight tests. He said, “I felt very comfortable with its performance from the first takeoff. The power module provides a real propulsive ‘kick,’ and I look forward to opening the aircraft’s flight envelope.”

VoltAero says it is gaining expertise that will be applied directly to its family of production Cassio aircraft. This includes integration of the entire battery power management system, the configuration of a new glass cockpit with optimised ergonomics for operation of the hybrid-electric power module, and the use of the company’s own battery packs with cooling systems.

The testbed aircraft is also equipped with two wing-mounted ENGINeUS 45 electric motors, supplied by Safran Electrical & Power and are installed in the forward-facing ‘pull’ position. Before Sunday’s flight, Cassio 1 had logged 14 hours and 25 flights aloft with the 45kW (70kW maximum) electric motors in a full range of operating conditions.


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