Flying cars, air taxis,
or their more formal term — electrical
vertical take-off and landing aircraft (eVTOL) — are not a new technology, said Nelson
García Polanco during the Tuesday afternoon session “Challenges and
Technological Opportunities of the New Urban Air Mobility and eVTOL Vehicles.”
Back in 1948,
Convair introduced the Model 118 ConvAirCar, which was a car with airplane
wings attached to the roof. In 1957, Popular Mechanics magazine had a “plane
car” on its cover.
But unlike these concept cars, today’s eVTOL vehicles are
fully operational, said Nelson, head of industrial technologies with CIRCE, a
Spanish technology centre that provides innovative solutions for industry.
Nelson said the current generation of eVTOL vehicles are the
result of technology convergence; “when a group of technologies come together
to make new things possible.” He cited the drone industry’s multi-rotor
configuration, fly control, miniaturization, and autonomous flight. Meanwhile,
the Tesla EV Roadster, which was launched in 2008, pushed the development of
patents and chargers.
There are three types of eVTOL vehicles in operation or
development, Nelson said:
Electric autonomous aerial vehicles like Spain’s
UMILES New Concept by Tecnalia, China’s EHang 216, Germany’s Volocopter, and France’s
CityAirbus. These vehicles have flight times of 15 minutes.
Lift and cruise vehicles with propellers, including
the United States’ Joby, Archer, and Wisk Aero. These vehicles have flight
times of 30 to 45 minutes.
Tilt concept vehicles like Germany’s Lilium Jet
and France’s Airbus Vahana. These vehicles have flight times of 30 to 45
Nelson said there’s also a new concept called Jetoptera, an
American-made bladeless propulsion vehicle that uses technology similar to
Challenges for the eVTOL industry include standards and
regulations. For instance, Joby has been working on U.S. Federal Aviation
Administration (FAA) certification for 10 years, Nelson said.
Another challenge is battery power density and charging
time. “Batteries are good now, but need to be far better,” he said. The average
eVTOL energy density is 200 watts per kilogram, but jet fuel has 15 times more
energy. And an EHang 216 needs one hour of charging for just 15 minutes of
flight. “But the good news is that batteries cost less now,” Nelson said.
One of the top eVTOL technologies and opportunities includes
noise reduction. Joby is 100 times quieter than a helicopter, Nelson said,
which can allow urban airport infraestructure to be centrally located.
CIRCE is currently operating an eVTOL test facility in
Zaragoza, Spain, called the Hera Drone Hub. The facility can test drones as
large as 500 kilograms, Nelson said. CIRCE is also studying conductive and
inductive charges, renewables integration and storage, and management software
for charging systems.