The power module for VoltAero’s Cassio production aircraft is now undergoing flight testing on the Cassio 1 testbed, marking another major step in the company’s development of a series production hybrid-electric airplane family for regional transportation that will accommodate four to 10 seats, with flight ranges of up to 1,200km. and cruise speeds of 200kts.
Cassio 1 made its maiden flight equipped with the power module Oct. 11, 2020, from VoltAero’s Royan-Médis Airport home base in southwest France, followed by two additional in-flight evaluations during the following two days.
The proprietary power module installed in an aft-fuselage pusher position combines three 60kW high-performance electric motors arranged in a triangular barrel configuration ahead of a 370hp internal combustion engine.
This power module configuration prefigures the full-up powertrain for VoltAero’s largest production Cassio aircraft version – the 10-seat Cassio 600 – with a total hybrid-electric power of 600kW (800hp), enabling 200kts cruise (360km/hr) – which is fast for an aircraft in its category.
“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,” explained VoltAero’s CEO and Chief Technology Officer Jean Botti.
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. With VoltAero’s patented series/parallel hybrid design, the power module can operate in modes from full electric to full hybrid, depending on the customer mission profile and range requirement.
Additionally, as the electric motors and internal combustion engine are linked to a common shaft that drives a five-blade pusher propeller, the ability for each to operate independently provides a high level of propulsion safety – with one source acting as a backup in case of a problem or failure of the other.
VoltAero Technical Director and test pilot Didier Esteyne, who was at the controls of Cassio 1 for the flight tests, said he was impressed by the power module’s operation.
“I felt very comfortable with its performance from the first takeoff,” Esteyne explained. “The power module provides a real propulsive kick, and I look forward to opening the aircraft’s flight envelope.”
By installing and flight testing the power module on Cassio 1, VoltAero is gaining significant 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 optimized ergonomics for operation of the hybrid-electric power module, and the use of company-developed battery packs with their cooling systems.
In addition to the power module on Cassio 1, the testbed aircraft is equipped with two wing-mounted ENGINeUS 45 electric motors, which were supplied by Safran Electrical & Power and are installed in the forward-facing puller position. Prior to the maiden flight with VoltAero’s addition of the aft-mounted pusher power module, Cassio 1 had logged 14 hours and 25 flights aloft with these 45kW (70kW maximum) electric motors in a full range of operating conditions.
In its latest configuration, the Cassio 1 testbed aircraft will be presented publicly for the first time during a VoltAero flight demonstration and program update event on Oct. 21, 2020, to be streamed live via the VoltAero.aero website.