machinery that puts the aircraft
back in to a readiness state.
“In this, it wouldn’t be so much
working on the motor or the
battery as swapping them in and
out and let the work be done at an
appropriate place, whether that’s a
maintenance hub or a depot or the
factory itself.”Change in the wind
Traditional helicopters are also
set to go through transformation,
shoved along by demands for
higher performance, lower cost,
more automation and less impact
on the environment.Helicopters of the future
will embrace hybrid power,
new philosophies in countering
rotor-torque, morphing rotor
blades, new fuels and technology
that will bring new capability to
the cockpit.
Of these, hybrid power is
rapidly becoming accepted as
a given part of the future of
rotorcraft moreso than it is forfixed-wing aircraft. Broadly,
hybrid power involves using a jet-
fuel turbine to run a generator,
which then distributes power to
electric motors. The theory is that
the engines will be quieter and use
less fuel.
“Already on existing helicopters
we can improve the actual
power transmission by adding
an electrical-hybrid system to a
turbine, improving, for instance
auto-rotation for single-engine
helicopters, what we call the
electrical back-up system,”
Krysinksi explains. “We have
tested it and we will continue to
do this. It means that putting on
an extra electric motor you can
significantly improve the auto-
rotation capabilities of single-
engine helicopters.”
Bell is also looking to hybrid
power to match rising customer
demands from their aircraft.
“When we looked at trying to
provide our customers with broader
mission capabilities, which included
higher payloads and ranges, we
thought hybrid propulsion as the
place to start,” says Drennan. “That
doesn’t mean we won’t eventually
get to all-electric and some of our
customers will demand that of
us, but we wanted to start with a
longer-range vehicle and hybrid-
electric is our approach.”
As perfect as that sound, there
are still obstacles developers need
to overcome before they have a
product they can present to the
market: energy management isonly one of them. The engines
require a certain amount of energy
at the rotor mast, but much is lost
in transmission, what the industry
calls “knock-downs.”
Scott Drennan believes that
knock-downs are not necessarily
knock-outs.
“You have an energy
management challenge just like
you do on any helicopter,” he pointAIRBUS HELICOPTERSAUSTRALIAN FLYING July – August 201826 Helicopters^ australianflying.com.au
wires to transmit power than
the geared systems that today’s
helicopters have.”
But even electric power is
not going to be enough to make
the air taxi a viable concept.
Manufacturers will have to
minimise down-time drastically
from today’s standards.
“Readiness is really important
for the future of air taxi missions,”
Drennan says. “It is today, and we
have some of the world ’s most ready
helicopters, both military and
commercial, but when you’re doing
2000 hours each year, which is the
goal of the future air taxi market,
that’s a different readiness level.
“We’re hoping for less on-
aircraft maintenance. We envision
things like the motors and the
batteries being swapped out for a
spare set that is there at the point
of operation. When you think
of the maintenance that goes on
today; a lot of work on complexfuels; characteristics more fitting
to the urban environments in
which these aircraft are going to
be operating.
The CityAirbus, by example,
is planned to have four double
propellers in rotor configuration,
which will lift around 2000 kg.
That’s four people and gear from
the centre of a major city out to an
airport on the fringe, over the top
of the frustrated drivers caught in
traffic jams.
Bell’s air taxi concept looks
for all the world like a futuristic
people-mover, but mock-ups
and drawings lack propulsion
systems. However, Bell is not
hiding that they, too, are working
with electricity.
Scott Drennan: “When
you think of a distributed
electric propulsion system you
can imagine electric motors
which allow for simpler hubs, a
transmission system that is just“ to be successful in the brave
new air-taxi world you have
to master efcient, light,
electrical power”
The Airbus H160 already features rotor tips with advanced shapes increase efciency and reduce noise.LEFT: Bell’s
futuristic air
taxi idea is
paving the way
ahead for the
company.BELL