But the batteries
take up so much
space there is
only room for
about half
the normal
passenger
load.
A normal
turboprop Cessna
has a range of
over 1,200 miles.
This new battery version
-- less than 500 miles
with just a pilot on board.
A normal
turboprop Cessna
can be refueled and
off the ground within
minutes.
This new battery version
will take hours to recharge.
This battery powered
test flight confirmed
the real problems
we already knew about
-- the low energy
density of batteries,
which means
they take up
far too much space,
and weigh too much.
That severely limits
the carrying capacity
and range of the plane.
Also, are the
lithium batteries
fire-safe?
And is lithium
mining “green”?
I doubt it.
From the
Manhattan
Institute:
“… The energy equivalent
of the aviation fuel
actually used by an aircraft
flying to Asia would take
$60 million worth of
Tesla-type batteries
weighing five times
more than that aircraft …”
Commercial aircraft
need at 30 minutes
of fuel remaining
at the end of a trip,
for circling the
destination if they
are unable to land.
Most of the fuel
had been burned up
during the flight,
so the aircraft is light.
But battery weight
is always there –
so adding 30 minutes
requires a safety margin
for an already constrained
range, which would be
expensive.
The battery has
the same weight
for the whole flight,
but a fuel driven plane
gets lighter during
the flight.
This affects
the range, and
fuel economy.
An electric plane
will have to land
with full takeoff weight,
so will need sturdier
construction, making
the plane heavier.
A battery aircraft
is always flying “heavy”.
So the minimum landing
distance is about the same
as its minimum take off
distance.
So a short local airstrip
may not be long enough
for an emergency landing.
Note:
A fully loaded 747
cannot land with
a full fuel load --
it has to shed
most of the fuel
before landing.
In the drive
to replace
hydrocarbons
as a fuel source,
it is overlooked
that a large amount
of oxygen is taken
from the atmosphere
for combustion.
The plane
does not
have to carry
this oxygen,
and it is free !
Storing sufficient energy
in a battery to make
battery powered flight
economic will be difficult,
and may not be possible.
While the cost
of the electricity
for the batteries
may be low,
the life cycle
of the batteries
has not been
included in those
incremental costs.
A Cessna commuter
propellor plane modified
to run on electricity
successfully completed
a 30-minute test flight
in central Washington.
Two Seattle companies
were behind the feat:
MagniX designed
the electric motor, and
AeroTEC modified the plane.
They say it was the largest
all-electric passenger
or cargo aircraft ever to fly.
Normally seating
up to 14 passengers,
the Cessna 208B
Grand Caravan
that circled
Moses Lake,
Washington,
was retrofitted with
a 750-horsepower
560 kW Magni500
electric motor that
weighs 297 pounds.
Power came from a
750-volt lithium-ion
battery system
that weighs two tons,
including cooling
equipment.
Those batteries
took up most
of the cabin,
leaving little room
for passengers,
MagniX CEO
Roei Ganzarski
told the Seattle
Times.
The two
companies
are pitching
the modified
Cessnas as perfect
for operating routes
of less than 500 miles
that transport
5 to 12 people
between regional cities
formerly operated by
small, so-called
“commuter” airlines,
AeroTEC CEO
Lee Human
told FlightGlobal.
Those carriers
have mostly
all folded as the
airline industry
moved to larger
regional jet service.
Sources: