global briefing
French Firm
ready for
first hybrid
flight
Aircraft developer VoltAero expects the first
hybrid flight of its prototype aircraft to take
place in the west of France in February, as it
aims for certification within three years and to be
manufacturing 150 aircraft a year by 2025.
There are around 30 hybrid fixed wing aircraft
in development around the world. Only a few
series-hybrid electric aircraft have been
successfully flight tested, such as the Diamond
E-Star and Ampaire’s Electric EEL.
VoltAero is headed up by former Airbus chief
technology officer Jean Botti and technical
director Didier Esteyene. Botti led the development
of the Airbus E-Fan, a prototype electric aircraft
that flew in 2014 which was built by Esteyene at
French company Aéro Composites Saintonge.
The startup, which is headquartered in Royan,
France aims to be one of the first to market with its
4-9 seater hybrid aircraft called Cassio, which
Botti believes could radically alter the general and
business aviation market. VoltAero has been using
two platforms so far in the development of its
Cassio hybrid-electric aircraft – a ground-based
iron bird for systems integration testing and a
flight testbed.
The flight testbed is a modified Cessna 337
Skymaster, which was chosen for the airframe’s
adaptability to Cassio’s “push-pull” propulsion
concept.
The flight testbed is being flown this month to
test the electric motors so their performance can
be mapped in preparation for their use in the
hybrid system. A nacelle has been installed on
each wing that will accommodate two EngineUS
45 electric motors, along with the associated
lithium-ion batteries for the “pull” propulsion.
During January, VoltAero engineers then plan to
remove the 337 Skymaster’s original front-facing
internal combustion engine, which is to be
replaced by a smooth nose fairing. The original
rear-mounted internal combustion motor will be
substituted by the hybrid power module – which
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incorporates three 60-kW EMRAX electric motors
and a 250hp (184kW) internal combustion engine,
both of which drive a common shaft for the
“pusher” propeller.
“We are confident we will have our first fully
hybrid configuration testbed flying by the end of
February or early March” said Botti, CEO of
VoltAero. “I think we will surprise many people
with our first flight. The aircraft will be significantly
changed in respect to the original 337 Skymaster.”
The testbed aircraft is expected to fly for around
20 hours before engineers modify it for its final 100
hours of flight testing by adding an optimized
propeller on the rear hybrid power module.
“We picked the 337 as our testbed because we
wanted distributed propulsion and nine seats. We
wanted to be able to maximize power output and
efficiency,” said Botti.
In the configuration to be validated during flight
testing, the “pull” electric motors’ propellers will be
used mainly during the Cassio’s takeoffs and
/AEROSPACETESTINGINTERNATIONAL.COM