overcome, but the sensation was
disturbing to say the least. Then
there’s the psychology of sitting
on top of a three tonne disc
spinning at 900km/h...Bill Shock
Ironically though for a
technology created to save
money, the Gyrobus
ultimately failed due
to cost. Because
bus operators
wanted a fast
recharge- three
minutes was
considered
too long -
the charge
voltage had to be
increased from 380
to 500 volts. This
gave the system
that 3.4 kWh/
km consumption
figure which, take
it from us, is bad.
Beyond Switzerland,
the Gyrobus system saw
deployment in Kinshasa in
what was then the Belgian
Congo, and in Ghent, Belgium.
Historical accounts are not kind:
the buses were criticised for
being so heavy they damaged
the roads, and they were
considered unreliable in the way
experimental V1.0 tech always
seems to be.
Anyway, trams won the war
of light commuter vehicles,
and then they too eventually
died out in a post-war world of
cheap petrol. But the flywheel
system was destined to live
again in a very different place:
the Kinetic Energy Recovery
Systems on race cars.Pole Position
There are a few
flywheel KERS
(including one
called Flybrid
which is
our kind of
wordplay),
and most
were created
to meet the new
“environmentally
friendly” rules in
Formula One. Far
from running the
entire car, they
recover kinetic
energy into batteries
or a (much smaller) flywheel.
These days we have amazing
synthetic lubricants and seals
capable of holding a vacuum,
and there’s little change that
a 5kg flywheel capable of a
60kW boost is going to escape
containment and cut a swathe
through the pits.
Indeed, between 2010 and
2014 there was talk of building a
larger Flybrid system to powerPOPSCI.COM.AU 81routes where drivers would
take short-cuts across rough
terrain, not so much.
Your Record Is
Scratched
The real problem with the
Gyrobus was that everything
about it was so extreme.
To give the bus even halfway
decent range, the f lywheel had
to weigh over three tonnes. And
it had to be spun up to 3000rpm,
at an effective energy cost of 3.4
kilowatt hours per kilometre.
And at 3000rpm, it meant
the outer edge flywheel
itself was spinning at a truly
insane 900km/h. There are
no reports of a flywheel ever
escaping containment, but if
it had the results would have
been... look, catastrophic seems
barely strong-enough a word.
Just imagine three tonnes of
anything shooting across a
crowded street at 900km/h
remains after doing a bunch
of complicated angular-
momentum calculations we’re
not paid enough to bother with.
More weirdly, the spinning
flywheel was big enough to
have a gyroscopic effect on
the bus. When the driver tried
to go around a corner, the
flywheel would make the bus
try to keep going straight ahead.
Apparently the gyroscopic
forces were relatively easy to
a whole car, and much was made
of the way that lithium-ion
battery systems were too heavy
and expensive to provide the
40kWh a car needs to be useful
for the daily commute.
Of course nobody counted
on Tesla making a real go of it
with the Model S. The cheapest
version has a 60kWh battery
system, and the top model
100kWh. Technology has beaten
the naysayers, in this case. The
Model S can carry around so
much electricity, there’s enough
for the silly Ludicrous Mode
and sub-four-second 0-100km/h
sprints to impress hipster
Silicon Valley types.
Volvo did some work
implementing a Flybrid system
into an S60 sedan, where it
would provide a 55kW helping-
hand to a 200kW five-cylinder
petrol engine. That was in 2014.
Today it must be tempting for all
car manufacturers to just buy
a bunch of Li-Ion batteries and
hide them under the boot.
Flywheel-powered cars
have a lovely steampunk feel to
them, but like so many alternate
energy systems, the negatives
outweigh the positives. They
have a role to play in certain
KERS implementations, but you
have to wonder if it’s only some
engineers’ irrational hatred
of electric cars that keeps
flywheel research going...Volvo’s KERS provided
a 55kW boost to a
petrol engineThis rather doubtful-looking diagram
comes from our August 1970 issue, where
the awesomely-named Alden P Armagnac
waxed lyrical about the potential benefits
of a flywheel system that could propel a
450kg car to 100km/h in just 15 seconds!
It’s not like this flywheel would have to
be stupid-huge like in the Gyrobus, either.
Just 750mm in diameter and weighing only
100kg. Of course, it would have to spin at
23,700rpm. And that means an outer-edge
speed of 3218km/h or, as military pilots
would put it, Mach 2.6. I wonder what it
would have SOUNDED like?IN 1970, WE BACKED
FLYWHEEL, BIG TIME