McLaren are pushing to the limit this season and tripped
over when they fast-tracked their blown diffuser in for Silverstone - but were
they right to give it a try?
The championship leading team had to gamble on an early
introduction of their blown diffuser concept in a bid to prevent Red Bull from
racing away at a high-speed Silverstone circuit expected to suit the men from
The concept, which was used in the 1980s and brought back
by Red Bull this year, aims to feed accelerated flow from the engine exhaust
system into the flow through the rear diffuser and around the rear wheels, but
the system dramatically changes the handling of the car and the way the
engineers need to set it up. It is also prone to instability as drivers get on
and off the throttle and it causes major overheating issues due to the 600
degrees Celsius air pumping into the rear flow field.
Having made the system part of its conceptual design long
before the other teams saw its 2010 machine, Red Bull has had plenty of time to
get over the problems - leaving their rivals playing catch-up and needing to do
so as fast as they can.
When McLaren introduced their system on Friday, both
Jenson Button and Lewis Hamilton struggled with the dramatic change in handling
of the car, with the latter ending up 1.5 seconds off the Red Bull pace. They
were forced to admit it is harder than it looks and decided to pull the system
off their cars after Friday practice.
The day of 'testing' on Friday was not a waste of time as
it gave them vital information about durability of bodywork parts and the
influence of the exhaust in terms of the shape of the exhaust plume -
information that will be vital to help engineers improve the package ahead of
the next race in Germany.
But the change back to an unblown diffuser, which
returned the handling to the traditional style much preferred by the drivers,
meant the team had missed out on the Friday set-up time needed to optimise the
car's performance for the Silverstone race.
The ban on in-season testing is what led McLaren to
introduce the untried design on their car at Silverstone, but it was also the
reason they had a solution.
The state-of-the-art McLaren simulator that has been
fast-tracked since testing was banned enabled Gary Paffett to get 'out on track' at
a virtual Silverstone and use models developed from the unblown diffuser car to
work out the best set-up to use on Saturday.
A real track engineer was able to sit with Paffett and
respond to his comments on the performance of the virtual car by plugging in
different numbers that change its virtual set up (using the same criteria used
on track like wing angle, spring stiffness, etc.). Complicated computer models
then use that information to alter the performance of the car, and enabled the
pair, through the night, to come up with the best set-up for in the conditions
expected for qualifying.
Details of McLaren's simulator are top secret, but Red
Bull's is believed to be equally capable and they are happy to reveal the
Test engineer Andy Damerum explained: "It uses the same
model we use for our F1 cars. The geometry, the power figures, the
transmission, gear ratios are all the same and you get the same sensations of
roll, yaw and pitch from the simulator as you would do on the real car. You don't
get the sensation of wind - but that is something we are looking at improving -
and the power steering is a direct copy of what we have in real cars being
modelled, so you get that feeling the effect of the downforce loading up the
The problem is, every driver is different.
So although the team was able to get a running start with
the modified cars on Saturday morning, Button still found it tough to get
settled. He was happy with the performance in the morning, but ran out of time
to develop it before qualifying and ended up in 14th place.
Paffett, however, will also have done long runs and the
computer simulation uses Bridgestone's tyre data to predict degradation and
wear through the race - something that is also a vital part of Friday running.
Ultimately, McLaren, thanks in part to Red Bull's
internal fighting, came out with a 2-4 finish - and if the data gained from
running the blown diffuser helps get a head-start in Germany, that can only be good for
their hopes of chasing down Red Bull.