T E C H N I C A L A N A LY S I S
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THIS DUCTS COOLING AIR TO THE HONDA ERS SYSTEM
THE INTERCOOLER OCCUPIES
THE RIGHT SIDEPOD
radiators and sidepods, but also
the loss in downforce from the
obstruction to the airflow of
these sidepods.
So engine manufacturers, along
with their lubricant partners, have
striven to run the engines hotter to
reduce the cooling demand, while the
chassis and aero teams have refined
the packaging of the sidepods to
reduce the negative effects of
the cooling package.
TURBINE MGU-H COMPRESSOR
TURBINE COMPRESSOR MGU-H
FERRARI & RENAULT
POWER UNIT PACKAGE
Last year, each of the three
manufacturers chose to package
their new power units in different
ways, with Mercedes uniquely
splitting its turbo between the front
and rear of the engine, then placing
the MGU-H on the same shaft
linking the two parts of the turbo.
This allowed Mercedes to run a far
larger compressor for more power,
while keeping the heat of the
exhausts away from the
compressor and minimising
pipework to and from
the intercooler.
Both Ferrari and
Renault mounted
their turbo more
conventionally
behind the engine,
with Ferrari
splitting the
turbo with the MGU-H. These
rear turbo layouts are simpler to
engineer, without the long shaft
linking the turbo housings at over
100,000rpm, albeit at the cost
of a smaller compressor size,
hindering power production.
With much speculation over
the winter, the manufacturers’
new layouts were expected to
follow Mercedes’ lead, but only
Honda has done so.
Even so, both Ferrari and
Renault have repackaged their
turbo installation, with Ferrari
dropping its old design for a more
closely coupled turbo set-up with
the MGU-H mounted in the V of
the engine just as Renault had
done, albeit with a much larger
compressor to regain the bhp
missing from its 2014 set-up.
mounted over the engine and
fed by the top half of the
rollhoop inlet.
This design does cost some
rear performance and raises the
car’s centre of gravity somewhat,
but the reduction is offset by
the size-zero sidepods and
rear-end packaging; McLarenHonda has gained far more
performance from the improved
diffuser airflow.
BLOWN FRONT AXLES
The aerodynamic efficiency of any
single-seater will be handicapped
by open wheels. These add
substantially to the car’s drag,
while the turbulent wake created
can also be sucked in between
the rear wheels and ruin the
performance of the diffuser.
To offset these effects, the
front wing can be used to create
a powerful airflow around the
outside of the tyres. This outwash
prevents the tyres’ wake tucking
back in around the car’s rear end.
Since last year the front wings
have been narrow, so teams lost
some of this outwash effect. As
a result, for 2015 teams have
reintroduced an old idea – that of
blowing airflow through a hollow
front axle to create that outwash.
Larger front-brake-duct scoops
capture air and pass it directly
through the axle and out via the
open end within the wheelnut. As
this air is forced out of the axle it
pushes the tyre’s wake outboard.
In effect, this is similar to the
Frisbee wheel fairings we saw
back in 2008-09.
One problem is there is no
pointed end to the axle, making
pitstops slower as the wheelgun
has to be positioned more
accurately. We can expect some
wheelgun/socket design variety
from McLaren, Red Bull and
Ferrari, which all use this solution.
AIR IS CHANNELLED
THROUGH THE AXLE
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MARCH 5 2015 AUTOSPORT.COM 43
PREVIEW
HONDA & MERCEDES
Some teams have changed the
placement of the coolers by moving
them out of the sidepod to feed them
from inlets around the rollhoop. One
team doing this is McLaren; thanks to
its bespoke Honda packaging, the
set-up is different to other teams.
Whereas the right sidepod contains
the turbo intercooler and the left
sidepod houses the engine’s oil and
water radiators, its ERS system is
then cooled by a larger radiator
SEASON
With the introduction of the
turbocharged and hybrid-based
power units last year, there was
also an increase in the heat put out
by these power units. Requiring
coolers for the turbo, as well as
the energy-recovery system, the
teams have had to compromise
aerodynamics, with larger coolers
inside larger sidepods. This costs
aerodynamic efficiency not only
because of the drag of the large
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COOLING