Will Gray

Gray Matter: The Buddh balance challenge

Will Gray

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The Buddh International circuit is one of the drivers’ favourite new F1 tracks - but the very thing that makes it exciting behind the wheel can also make it tough to overtake.

The Indian circuit is one of F1’s most recent success stories in terms of design, with some drivers describing its mix of fast flowing curves and long straights as being like a modern version of Belgium’s legendary Spa-Francorchamps.

It offers a real challenge as it rewards a good rhythm and punishes mistakes – and within the mix there are several corners described by Sebastian Vettel as “rhythm breakers” that if got wrong can completely wreck a lap.

This type of circuit is also one that the engineers enjoy, because with many of the corners flowing into each other it requires the car to cope with quick direction changes and that puts a focus on the fundamentals of aerodynamic balance and stability.

In a wind tunnel, engineers not only test the aerodynamic properties of the car in a straight line but also move and tilt the model to test for pitch and yaw effects.

The modern advanced tunnels now allow aerodynamicists to go beyond this and put a car through an entire track test – using computer controlled mounting arms to move and turn it as if it were driving around any specific track they choose to program into the system.

On a track like Buddh, the trick is to balance the amount of downforce on the car front and rear to enable it to stay as settled as possible through the switches of direction, and to minimise any drop-off in downforce due to yaw (left-right turning) and roll, the latter of which causes changes in relative ride height from side to side.

Balancing the car with too much front downforce will make the car too grippy and too responsive, making it twitchy and hard to drive in the faster corners, but going too far rearwards reduces the control needed to hit the perfect lines in the fast flowing sections and also reduces braking stability when slowing from the fast sections.

A good example of this is the section from turns five to seven, in which a driver enters on a fast left-hand corner then slows by around 40 mph for a second left-hand turn before accelerating out through the fast right-hander on exit.

Following this, the partially banked double apex turn 10-11 into 12 sees the car lighten in the middle, and without the right aerodynamic stability and balance that can prove tricky.

It is also a circuit that offers significant benefits from intelligent use of KERS, as there are many options around the track where it can be used to good effect – and with only limited availability, drivers and team strategists must plan exactly when and where to use the boost.

And that intelligent use of KERS, along with the DRS effect, will be crucial because the fast flowing corners may be enjoyable for the drivers but they do not promote overtaking at all.

There are only really two places to overtake – the back straight and the long straight into turn four – as the rest of track, despite being very wide, really has only one racing line and has a bigger safety net than normal to allow drivers to push for perfection on that line.

The flowing corners benefit the car in front because it is hard to travel in its trailing wake - so between the two potential passing points, the chasing car will drop back due to a relative lack of downforce through the corners.

Having won two from two in India, Sebastian Vettel looks favourite, especially as he is currently on the best form of his life and his Red Bull has excellent braking stability and high-speed balance.

Lotus and Mercedes have also shown good performance in these areas but their only hope really rests on the use of a softer tyre compound compared to last year, with Pirelli supplying soft and medium rather than the medium and hard they provided last time around.

The longer than average pit lane has typically pushed strategists to choose fewer stops – last year it was a dead-set one-stop race - but this year the softer compounds could allow some teams to choose to qualify on the medium and have enough pace and life on those tyres in the race to enable them to mix up the strategies.

That said, in the race previews, Kimi Raikkonen described Buddh as “a good track to go fast with a strong car in front of all the others.”

So step forward Vettel. Surely it’s hard to imagine another winner...

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