Thursday, 21 April 2011

So How Come There is Overtaking in F1 Now?

2011 has seen an exciting start to the season with plenty of drama, plenty of pitstops and plenty of overtaking. This is something that has been missing from Formula 1 recently, so how come we get so much passing this year?

The FIA have been trying to get more overtaking in Formula 1 for several years now, grooved tyres, movable front wings and forcing the teams to use different tyre compounds have all been used in the past with little success. But this year everything seems to have come together perfectly to create the right conditions for lots of excitement. Strangely the few rule changes this season show that they have less to do with this increase than the FIA and its "overtaking working group" would have hoped. Lets look at the main areas.

Photo courtesy of Team Lotus

Or possibly tires if you're from the USA! The single biggest change this year is the tyre supplier. Pirelli have taken over from Michelin for 2011 to outfit Formula 1 with its endless need for sticky rubber. Pirelli tells us that they were asked to provide a tyre which would provide racing like that seen in Canada 2010 and they have provided even better. There was a fair bit of concern over the life of the tyres in pre-season testing which has (thankfully) not carried over into the season itself. This is mostly down to the temperature ranges during winter testing compared to the summer racing season. But now the warmer months are starting the rubber is working just as designed.

Pirelli have created their tyres with two layers of different rubber compounds. The outer layer is the serious sticky stuff which provides lots of grip but wears out quickly. The inner layer is much more durable but doesn't provide nearly as much cornering force. This is what the teams are talking about when they say the tyres are going into "Phase 2". The stickiness has gone and its time to get into the pits and get a new set. This change in compound leads to large changes in performance happening very quickly at different times for different drivers.

Teams are also required to used two different compounds during the course of one race. Thanks to the knockout qualifying system, this means that a variety of tyres are used at the start. The lap time change between hard and soft can be as much as one second per lap. But when the softer tyre runs out of grip, the harder version still has some left, which again leads to large corner speed differences.

DRS (Drag Reduction System) and Aerodynamics

Over the last few years the bodywork of Formula 1 cars has changed quite a bit. First the winglets all over the sidepods of the cars have been removed. Then the rear wings were narrowed and the front wings widened. This was part of the Overtaking Working Group's suggestions to improve overtaking, but by itself it didn't do the job. The narrow rear wing was introduced (and the winglets removed) to reduce the turbulent wake behind the car. Air that's swirling around is at lower pressure than nice still air and so any following car would not have as much grip as the lead car. The air is still moving quite a lot even with a smaller rear wing though, so larger front wings are required to help create sort the air out for the chasing car.

To improve the situation even more the Drag Reduction System (full description) was introduced. This means that just when a driver needs less drag he can get it. The wing flattens out and the top speed of the car increases. Again a large performance difference is created, this time on the straights.

KERS (Kinetic Energy Recovery System)

The Kinetic energy recovery system has not really factored into much talk of overtaking. It would seem that because all cars have it, its not really a difference in performance. Besides which Red Bull seem to be doing quite well even though they can only get it to work half the time! KERS works by capturing braking energy that would otherwise be lost as heat, storing it, and using it to boost engine power at other points in the lap. The big trick is that it only stores enough power for around 6.5 seconds per lap. This means that a defending driver can use all his boost well before the end of the lap. A chasing driver can still have some left before the lap is over and that, once more, leads to a big difference in speed. This time on acceleration.

Overtaking and Strategy

Large performance differences mean overtaking and Formula 1 this year has seen plenty. The DRS and tyre situation has created the differences but, most importantly, created a change in the performance of the cars during the race. This means that you can't qualify on pole and have the fastest car for the entire race. Each of the cars will have some period being faster than someone else. Maybe not everyone, but someone! The big trick is to take advantage of that change.

Mark Webber showed how important that can be in China. He spent the first stint of his race stuck at the back of the grid going nowhere before a change to the softer tyre put his car back on the performance level of the front runners. The Australian took advantage of that jump in speed to quickly climb the leaderboard. Some well timed pitstops and good overtaking were all he needed to take a place on the podium.

Overtaking is not taking place in just one spot either. There were fears that DRS would mean passing at the end of the main straight and nowhere else. Some good (or possibly lucky?) positioning of the activation zone has stopped it being too much of a sure thing. With luck (always a vital ingredient), the changes can come together and provide a passing opportunity pretty much anywhere on the track. 

The excitement looks set to continue for the rest of the season. The track in Turkey provides several passing places, as we have seen in previous years, so this year should be a classic race.

1 comment:

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