The Belgian Grand Prix was a race where a lot of decisions needed to be taken, many on the hoof, due to the uncertain weather conditions, which had prevailed throughout the weekend.

It is a fascinating case study in how teams and drivers pick their way through a race, based on the evidence of Friday practice, best guesses about what the other teams will do and lots of instinct.

Big decisions on Saturday had a knock-on effect to Sunday. Timing the final qualifying run was everything and Mark Webber and Red Bull got it just right, putting on a new set of soft tyres at the right moment, just before rain fell, to set the pole lap.

Photo: Ferrari

Fernando Alonso wasn’t so lucky, he saved his new set of tyres for later in the session and rainfall prevented him from improving. This was bad luck. But Alonso was in the position of only having one set to decide when to use, because he had used a set of new tyres earlier in Q2, which he would not normally do, but had been concerned about making the cut.

So the result was that the car which had set the fastest times on Friday and looked a contender for victory, started the race tenth on the grid as a result of a series of decisions.

The following day, during the race, he and the team were forced into a quick decision after he was hit by Rubens Barrichello at the end of the opening lap.

Going into the weekend, Alonso had said that the driver who gambles would win, but he was forced into a gamble by this early stop. It had started raining and they gambled that the rain would fall for a long time, so fitted a set of intermediate tyres. It didn’t rain any more and he was back in for slick tyres three laps later. This dropped him to 20th place, another opportunity to win a race or at least get a podium, gone. Although luck played a part here, Alonso would be the first to admit that some of the decision making this year has cost him.

Photo: Getty/Red Bull

Once the race settled into a rhythm, the key decision for front runners was when to make the first stop. They wanted to delay it as long as possible, because they were getting diminishing performance from the tyres, but they wanted to hold out as long as possible in case more rain fell so they could go straight onto the wet or intermediate tyre.

Adrian Sutil and Force India were again very competitive at Spa.

Sutil had qualified 8th, especially as he had been in the same boat on new tyres as Alonso. Force India are at the level of competitiveness where Q3 and the top ten are the target and any places they make up after that after that are a bonus. So he did well to qualify ahead of Alonso in the circumstances.

Sutil was running fifth as the teams started to think about making that first pit stop. He had started on soft tyres and as the race had been declared wet, there was no longer an obligation to use hard tyres, the teams had a free choice.

The hard tyre was not as easy to warm up and not all the drivers could get the speed out of them, but the majority of drivers went for them.

The decision the teams make is based on constant monitoring of their own cars and the opposition using the timing loops every 100 metres around the circuit. Rather than rely on information at the end of each of the three sectors, the strategists are assessing the situation every few seconds. If they see the tyres on their car starting to go off they know it’s time to pit and by following the progress of other cars they can decide what is the best tyre to go on to.

Mercedes had started the race on the hard tyre, hoping it would last long enough to see them to when the rain came. They were behind Sutil on the road at the time he stopped.

They had suffered a lot of degradation and so when Sutil stopped on lap 21 he lost the place to the Mercedes, but was two seconds a lap faster and able to pass them easily. They finished behind him in 6th and 7th places.

Sutil’s pit stop started the trend for the other front runners, who pitted soon after.

With this in mind, it would have been very interesting to see what Rubens Barrichello might have achieved on his 300th Grand Prix start as he too started on hard tyres from 7th place on the grid. He would likely have finished ahead of Sutil and may even have challenged Massa for fourth.

The final decisive moment was near the end when the rain started to fall and yet the teams wanted the drivers to stay out on slick tyres as long as possible. This tactic almost spelled disaster for Lewis Hamilton, who went off the road, but was able to keep going.

There were several reasons why the teams were so reluctant to bring the cars in; we had seen on Friday that the intermediate tyres were too soft for Spa and were going off after two laps. The rain started falling 12 laps from the end and that would have been much too long for those tyres. So the decision to pit was based on a risk assessment; which was more risky, leaving the drivers out on a wet track on slick tyres or bringing them in with the risk that it doesn’t rain hard enough, and/or the intermediates go off rapidly and you then face an uncertain few laps, maybe another stop, which could cost you your result?

Amazingly, they concluded that it was safer to stay out on slicks.

However, calm, rational risk assessment is one thing, human emotion is another. When Hamilton went off, all the strategists got cold feet and decided to abandon their plan and bring their drivers in !

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Formula 1 started up again at Spa Francorchamps after the summer break, which incorporated a compulsory two week factory shutdown.

Despite the lack of development time during this period, there were nevertheless some fascinating technical stories, including two significant upgrades on front running cars, which had been scheduled for the Belgian Grand Prix weekend.

And there was also a more stringent test to ensure that front wings do not flex beyond what the amount allowed in the rules. Would this force Red Bull and Ferrari into changes and slow them down?

And we’ll also look at the difference between the wet set up and dry set up of the two Ferraris.

Flexi wing tests
After the heated debate in Germany and Hungary about the Red Bull front wing flexing to increase front downforce, a new more stringent test was introduced by the FIA. Red Bull passed the test.

The Red Bull wing at Spa featured fewer elements than the Hungary wing and observers say that it did not flex out on track as much as in Budapest. The team says that they have changed nothing in the wing apart from things they would normally do when moving from an ultra high downforce circuit like Hungary to a faster circuit like Spa. However senior composites technicians from the team’s Milton Keynes base, who do not normally attend Grands Prix, were noticed in the paddock, which means that something out of the ordinary was taking place. The theory is that the wing flexes outwards due to a sophisticated layering process of the carbon composite material.

The new test involved double the load being placed on the wing, so now it was now 100kg. As the severity of the new test is arbitrary, there has been a considerable amount of lobbying of the FIA technical people by Red Bull and Ferrari on the one hand and McLaren and Mercedes on the other.

The outcome from Spa was that McLaren and Mercedes were both privately unsatisfied that the test was stringent enough, while observing that the Red Bull wing flexed less than it had in Budapest, when out on track. The car was much closer to the performance of its rivals than it had been in Budapest, but there are several possible explanations for that, including the weather and the fact that the wing has significantly fewer flaps and thus is creating less downforce anyway.

Rivals suspect that the flexibility of the floor stay may be a larger contributing factor to Red Bull’s speed and have successfully lobbied the FIA to introduce a more stringent test for Monza.

As Monza is a low downforce, power circuit and Red Bull’s deficiency is in engine power, they are likely to be at a disadvantage there anyway and it will be tricky to draw many conclusions on what effect these new tests have had. We should see any differences more clearly in Singapore and particularly Suzuka.

New Ferrari diffuser
Ferrari had a significant upgrade to its diffuser in Spa. The team introduced an exhaust- blown diffuser for the first time in Valencia, copying the idea which Red Bull had revived this year. The concept uses the gas pressure of the exhaust passing through the diffuser to gain more downforce.

The blown diffuser is a complex piece to get right and Ferrari’s strategy was to introduce a basic model and get it working quickly, learn from it and then introduce a more sophisticated one at Spa. This strategy seems to have worked quite well, the team did not lose time in getting it working as McLaren did, for example.

The new diffuser is similar in concept to solutions on the Renault and McLaren. There is a very large hole, made legal by two longitudinal fences which run the length of it. The lower channel of the central section of the diffuser, has a slightly different top profile, whose outer edges now are rounded downwards.

There were also small changes to the bottom tips of the rear wing, which echo Red Bull.

Alonso’s rear wing on the grid at Spa

For qualifying and the race, held in changeable weather conditions, Ferrari ran two different specifications of rear wing. Fernando Alonso ran a slightly higher downforce wing, which was therefore more of a wet set up, while Felipe Massa ran the lower downforce example. Massa’s was the newer design and it featured different end plates with curved gills similar to Red Bull, no slot between elements and a smaller main wing element.

Performance wise the differences were subtle but still noticeable. On the fastest laps in qualifying, Massa’s car was 2 km/h faster through the speed trap than Alonso’s and was a tenth of a second slower through the middle sector of the lap, which is a good indictor of downforce.

Massa’s rear wing on the Spa grid

Both wings incorporate the drag reducing F Duct device, which showed its greatest advantage of the season so far around Spa. With the need for high downforce in the middle sector and good straight line speed on the two long straights in sectors one and two, cars equipped with F ducts could have it both ways and the device was worth half a second per lap here, a huge amount by F1 standards for a single component.

Next time out on the high speed Monza circuit it is likely that the teams will not use the F Duct. As the elements of the rear wing will be so small, it’s hard to incorporate the device and the performance gain is small in any case.

Renault F Duct
With so much to gain from running an F Duct at Spa, it was the perfect time for Renault to introduce their version. This being round 13 of 19 races, it comes quite late, by the standards of a top team. McLaren pioneered the idea at the start of the season, Sauber had one soon after and Ferrari and Force India soon followed. It’s another complex piece of engineering, involving fluidic switches, which channel and switch on air flows.

Renault has been rebuilding its aerodynamic capacity after the difficulties of 2009 and has focussed on perfecting other areas of the car, like front wings and blown diffusers before trying out its F Duct. The strategy has worked and the car has been steadily improving, as shown by Vitaly Petrov’s season best results in Budapest. So the half second gain from the F Duct at Spa put Robert Kubica right in the hunt at the front of the field. He both qualified and finished in third place.

In common with most systems where the F Duct concept is an add-on, rather than designed into the monocoque like McLaren, the drivers activate the system using their left hand.

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The Hungarian Grand Prix has developed a reputation as a bit of a dull race over the years, although there have been some races where due to strategy reasons, the race has been enthralling.

One that springs to mind was the 1998 classic, when Ferrari’s Ross Brawn switched Michael Schumacher on a three stop strategy, which required him to knock out 20 laps of qualifying level intensity to beat the McLarens of Mika Hakkinen and David Coulthard.

Webber: Reprised Schumacher’s 1998 performance

He was 12 seconds behind race leader Sebastian Vettel when the safety car came out. If he had pitted that lap he would not have had to queue for service behind Vettel, so that was not a factor in his decision. But it’s interesting to note that, since Valencia, where Felipe Massa lost a lot of time and track positions, it’s been established that queuing cars in the pit lane under the current safety car rules is a bad idea, unless it’s raining.

Interestingly, Massa followed Alonso into the pits again this weekend and was only three seconds behind him on the lap when the safety car came out. Having suffered at Valencia and to avoid queuing, he backed the pack up by a further four seconds on the way into the pits. But this backfired as he lost a place to Jenson Button in the stops!

After the restart on lap 18, Webber knew that his task was to open up a big enough gap over Fernando Alonso to be able to pit and retain the lead. This would need to be in the order of 20 seconds. Even at a second a lap, this would mean taking the super soft tyres to lap 38 and taking a lot out of them to achieve the lap times.

Bear in mind also that the tyres which start the Grand Prix always take an extra pounding from carrying the extra fuel weight at the start.

So Webber’s and the team’s decision to adopt this strategy was very bold. But he made it stick.

When you look in detail at the race lap chart, you realise that it only just worked out for him. By lap 37 he had 19 seconds lead, then by lap 40 he had it up to 22 seconds, but then the performance of the tyres began to go off and from doing high 1m 23s laps, he did two high 1m24s laps. Any more of that and his margin would have gone, so he pitted and got out ahead of Alonso. But there wasn’t much in it and this is a credit to Alonso for making him work extra hard to build the gap.

The performance of the tyres on Webber’s car in the first stint shows how safe a tyre this super soft is and the temperature had a lot to do with that. Tonio Liuzzi did 55 laps on it as a second stint, having started the race on the hard tyre. It was clear that the soft was the fastest tyre last weekend, the question was whether to try to spend most of the race on it.

It was interesting therefore to compare and contrast the decision of Barrichello and Williams to start on the hard tyre from 12th on the grid and with Kamui Kobayashi starting 23rd on the super soft.

There are two tactics to starting the race on hard, one is to do a short first stint and then spend most of the race on the faster tyre, as Liuzzi did. But this only works if you can pass cars, which isn’t easy in Hungary.

The other tactic of starting on the hard and running a long first stint hasn’t helped anyone gain places this season in a race, except Kobayashi in Valencia, where the safety car removed most of the cars in front of him.

Here Barrichello lucked into a safety car too, which moved him up to 6th place and after staying out to lap he ended up fighting with Michael Schumacher over 10th and 11th places. But Schumacher had started 14th on the grid on the soft tyre, so his strategy would seem again to be the better one.

Bearing in mind that Barrichello and the other cars around him on the grid all gained three places from the retirements of Rosberg, Hamilton and Kubica. So by starting on soft and following the herd, Barrichello would have finished at least 9th.

But then we wouldn’t have had that awesome battle with Schumacher at the end of the race to savour….

Contrast that with Kobayashi who started 23rd, got a great start and was up to 14th place on the first laps. He then pitted a lap later than the majority, to avoid having to queue behind De La Rosa – he was six seconds behind on the road. He nailed Schumacher at the restart and was in the group that moved ahead of Barrichello when he made his late pit stop. He finished in the 9th place that should have been Rubens’.

The other key decision which made for a real talking point on Sunday was the release of Robert Kubica from his pit box into the path of Adrian Sutil. The Renault team was penalised for this unsafe release, which was clearly affected by the chief mechanic being distracted by the loose wheel from Rosberg’s Mercedes coming down the pit lane. No-one can blame him for that.

However the normal protocol when it comes to releasing a car is if in doubt don’t release it. That is the safest way. But here the approach seemed to be to let the car go and deal with it afterwards, which is disturbing.

This is an area where the thinking behind split-second decision making needs to be realigned back to a ’safety first’ mentality.

Renault are among the fastest at pit stops this year, along with Red Bull. while Mercedes have been the fastest in general, partly thanks to an ingenious front jack, which pivots sideways when the car comes back down to allow it to drive away immediately.

With the Hungarian Grand Prix falling just one week after the German race, there wasn’t much time for the teams to add major updates to the car, however there were some scheduled updates, such as the blown diffuser on the Force India car, which was used only in the practice sessions and some interesting solutions for getting maximum downforce.

And as the weekend’s action revealed, downforce was everything at the Hungaroring.

The two main talking points were the Red Bull flexi front wing and the Renault rear wing, which gave the team a good performance boost and yielded a best ever F1 finish for Vitaly Petrov.

Red Bull front wing
The anaylsis of the Red Bull front wing is in two parts this week. There is a separate post on the FIA’s decision to apply a more stringent test to front wings at the next race and what this means for Red Bull. Here we will look at the wing itself.

The concept of applying aero elasticity to F1 wings is not new, in fact it goes back over 30 years. Wings which flex at speed have appeared at various times over that period, when new technology allows the rules to be circumvented and new rules the performance gain is attractive enough. This is such a time, due to the new wide front wing rules.

There are two points of view on front wing flex; one is that a rigid front wing will give you exactly the same results on the track as you get in the wind tunnel and in the Computational Fluid Dynamics programmes. The other is that the lower you can get the wing tips to the ground, the more downforce you will generate and this will be faster.

A flexi wing can bring gains of 2/10ths of a second or more in the wing tips alone, but there are risks to this approach.

It is easy to end up with a wing which makes the car loose in high speed corners, which spooks the driver. It can upset the balance of the car with some strange results. The reason for this is that it is not possible to do wind tunnel tests and CFD programmes with deformed shapes, which replicate the full flexing of the wing with the car at various angles in cornering. It’s just far too complex to model. So having a flexing front wing is a bit of an unknown.

Another problem is that by definition, if it is flexing and thus creating more downforce as you go fast down the straights, it is therefore also creating more drag. And then when the driver lifts off the throttle and the wing rises up it drops downforce and can make the car unstable in a slow corner.

However it is very good on medium and fast corners, such as are found in Sector 2 in Budapest, where the Red Bull was untouchable last weekend.

Renault rear wing
The aerodynamics department at Renault has been very busy with updates this season, particularly front wings, with countless iterations, which have made the car steadily faster. The car was competitive in Monaco and again at the high downforce circuit in Budapest, Renault was on the pace, vying with McLaren for third fastest car last weekend behind the Red Bull and Ferrari.

In Hungary Renault introduced a new rear wing especially designed for high downforce. The wing features a deep V shape in the middle, main profile and the flap is divided in two sections by means of a large hole.

As with the McLaren and the Mercedes, the elements of the wing work as if it was constructed of three separate elements.

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The German Grand Prix at Hockenheim didn’t turn out the way many people expected for many reasons and there were some big decisions taken, which we will be talking about for some time.

The two widely different tyres behaved far better than expected, leaving few tactical options to the teams, while Ferrari were more competitive than many had expected and were the centre of attention. They took a one-two finish, but not in the same order in which they ran for most of the race.

Ferrari: Mechanism to prove who’s faster (Darren Heath)

But what was the mechanism by which this crucial decision was taken?

If it had been agreed before the race that Alonso was the driver Ferrari wished to take maximum points from the race, then there would have been an arrangement in place to switch the cars around if Massa found himself ahead. It doesn’t appear to be the case here and anyway I doubt whether Massa would have agreed to that.

However he would have agreed to a system for establishing who is the faster driver. It seems that there was an agreement in place about the size of lead and a mechanism for showing who is faster, as a basis for Ferrari to make a decision. This may be a legacy of incidents earlier in the season, such as Australia, where Alonso was held up by Massa and the team took no action.

Judging from the messages to Massa from his engineer Rob Smedley, it seems that the notion of a three second lead was important, Smedley pointed out to Massa that he had three seconds in hand over his team mate at one point and described that as important.

But Alonso soon ate into that lead, getting it down to below a second, which was his way of proving that he was faster. Faced with Massa’s inability to match the pace and having lost the three second lead, the team had the evidence it needed to tell Massa that Alonso was faster than him, which was clearly the agreed etiquette.

I’ve been researching this a bit over the last few days and this kind of arrangement is quite common within teams. There has to be some way for teams to assess which driver is faster on the day and if the driver who is following can prove that he can close up a gap then it shows that he is faster.

This tipped the balance in Alonso’s favour in Germany.

We saw it last year in Germany when Jenson Button was behind Rubens Barrichello and Ross Brawn radioed the Brazilian to say that they were losing time to Rosberg and that if Barrichello couldn’t keep the pace up then he “should let Jenson have a go”.

So it was last weekend; with a threat from Vettel in third place and mindful of the championship situation, Ferrari formed its decision.

On a wider theme, the much discussed three step gap between the super soft and hard tyres didn’t create the tactical variations many had hoped for. Both tyres were just too good and a repeat of the chaos of the Montreal race was never on the cards from the early practice sessions onwards.

Hockenheim is a track which improves quickly once some rubber goes down and despite the rain over the weekend, it rubbered in and this meant that the supersoft lasted well in the opening stages of the race.

This caught out Mark Webber, who pitted on lap 15 and lost a place to Jenson Button, who pitted on lap 24. Webber had done a run on Friday on supersoft, where he had quite a lot of graining and this might have spooked him a bit into deciding not to run too long on that tyre in the race, even though he knew he was racing Button, who was likely to run longer.

Conversely it was another example of Button’s smooth driving style giving him the ability to make a set of option tyres last longer than his opposition. He did the same in Silverstone where he gained two places by staying out longer. Here he jumped Webber and picked up a vital position.

Button was helped in this by the new tyre pace on the hard, which wasn’t great. Although the track temperature of 25 degrees meant that the hard tyre didn’t struggle to warm up, neither did the new tyres give an injection of pace, so a well managed set of used supersofts was still faster than a new set of hards. The situation was tailor made for Button.

The experiment of the three step gap revealed that the four tyres in the Bridgestone range are too close together to make much of a difference. What made Montreal so enthralling was that both tyres were suffering from high degradation.

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The German Grand Prix at Hockenheim will be remembered for the team orders row which blew up after Ferrari ordered Felipe Massa to let Fernando Alonso through, but it was also notable as a confirmation that Ferrari has made great progress with its car after a period in the first third of the season where it fell behind in development.

Unlike Red Bull and McLaren, Ferrari has been obliged to copy both of the key technical innovations of the 2010 season; the F Duct rear wing and the blown diffuser. McLaren invented the former and Red Bull the latter so both have had half the work to do compared to Ferrari in overall incorporation of new tech.

Ferrari worked first on the F Duct and got bogged down with it, then the blown diffuser was introduced later. The signs were clear in Montreal that Ferrari had taken a step forward and then in Valencia they introduced the blown diffuser. In Silverstone the step in performance was confirmed with Alonso being barely a tenth off the Red Bulls through practice and the early part of qualifying, but at Hockenheim it all came together and Fernando Alonso qualified on the front row, with Massa just behind. In the race, Ferrari had better race pace than Red Bull, indicating that they are contenders for the second half of the season.

Ferrari updates get them in the game
Hockenheim was the third outing of the blown diffuser introduced in Valencia and detailed changes to the exhausts and floor optimised the solution together with a refinement of the F-duct system. Ferrari have modified the side channels of their diffuser. This one now sports a wider and diagonal opening compared to the standard perpendicular one seen in Valencia when the solution was introduced the first time.

Ferrari also had a step on the front wing, which improved the overall downforce and stablity of the car, leading both drivers to talk of greatly improved grip and driveability. Another big step from Ferrari is due at the Belgian Grand Prix at the end of August, where heavily revised back end aerodynamics will be brought out.

Mercedes rear wing
Mercedes, for its home race brought an array of small developments, the main one being to the rear wing main profile, now featuring two big slits in its central section, to increase the efficiency of this element producing a slightly increased downforce load. The main feature is a double large opening, placed in the middle section of the main profile, mimicking the effect of an additional flap. This solution helps in terms of increasing the downforce load generated by the wing. Mercedes do not have the full active F Duct system operated by the drivers, as used by its rivals, they have a more passive system. It was useful in Germany, although the car is still short of the pace of its rivals and will be even more useful in Hungary.

McLaren blown diffuser
McLaren ran the blown diffuser all weekend in Germany, although their deficit to Ferrari and Red Bull in qualifying and at the end of the race indicates that there is still work to be done to optimise it. In Silverstone they removed it after Friday practice because it was overheating components in the rear suspension and the on-off nature of the exhaust gas pressure, combined with the bumps in the Silverstone track was causing instability.

In Germany they introduced modifications to reduce the overheating problems and now the exhaust pipes are in a more external position , sporting a diagonal cut instead of the perpendicular one adopted previously. This is still a work in progress and McLaren now need to add the next step in performance to stay with the Red Bulls and Ferraris.

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The British Grand Prix at Silverstone was the first race on the new circuit layout and we had some great racing. There were some interesting tactical calls, made both before and during the race, which affected the outcome.

As far as race tactics are concerned, the strategy was decided for the top ten teams by the qualifying rules, so having all opted to qualify on the faster soft tyre, they were obliged to start the race on it.

All the other runners outside the top ten, who had a choice, did the same, with the exception of the Force India cars of Adrian Sutil and Tonio Liuzzi.

Sutil gambled on hard tyre (Darren Heath)

They decided to take the hard tyre for the opening stint, because they knew that the soft would be the better tyre and they wanted to spend most of the race on it. They wanted to us the hard at the start to get them far enough into the race to make the soft viable to the finish.

However from their experience we learned something about the way races are unfolding tactically, which means that it is unlikely we will see anyone repeat their experiment in a hurry.

They believed that they had a fast car out of its natural position, in other words, Sutil should have been several places ahead of where it was, in front of the likes of De La Rosa and even Barrichello. So by running longer than their rivals, the theory was that they would be able to undercut them and pass at the pit stops and then in the second part of the race, be on the faster tyre when their rivals were on the slower one.

However because the opening stint of the race is done on the maximum fuel load, we have seen several times this season that the tyres get disproportionately damaged in the opening stint, regardless of whether they are soft or hard. Canada was an extreme example, where the hard was lasting not longer than the soft, as Red Bull’s drivers and Kubica found to their horror.

In Silverstone the left front tyre was taking a lot of damage on both types of tyre, but the hard wasn’t working well generally. So by looking at the lap times of the competitors in front of them, Force India could see that Sutil would not have the performance to build a margin by staying out and extra five or ten laps.

Instead, the cars on the soft tyre who pitted early would be in a position to jump Sutil. So reluctantly they had to abandon the plan and pit Sutil on lap 15, at the same sort of time as his rivals.

However doing the tyres this way around did have some advantages; it meant that they were on the better tyre for longer and it meant that when the safety car was deployed on Lap 29, the superior warm-up on the soft tyre, meant that they had an advantage over the cars in front, including Schumacher.

Sure enough a lap after the restart, Sutil was able to pass Schumacher for seventh place.

If using the hard tyre at the start didn’t work, the tactic of staying out longer than the opposition to make up places was successfully carried out by others on the soft tyre, which shows how well it was working. Jenson Button and Nico Rosberg in particular, gained.

Rosberg was fighting Kubica for third place. He was also mindful of the fact that with the Renault restricting the pace, Alonso was a threat from behind. Alonso pitted on lap 12 trying to undercut the pair of them but fortunately for Rosberg, Kubica pitted a lap later. Rosberg stayed out two laps longer and jumped him, thanks to a very quick in-lap. That left Kubica in front of Alonso and a battle which ultimately led to a penalty for Alonso.

Button had another strong race tactically (Darren Heath)

A more extreme example was Button, who had had a poor qualifying performance and was down in 14th place on the grid. He moved up to eighth with a brilliant start and then stayed out until lap 21. By doing so he was able to jump Schumacher and Barrichello.

An even more extreme example, which backfired, was Nico Hulkenberg in the Williams. He started 13th on the grid and stayed out on the soft tyre until lap 27. It was too long and the tyres had gone away by the time he pitted. There was no gain at all.

As a sidenote, Hulkenberg was very unlucky he did not pit two laps later, as the safety car came out on lap 29 and he would have made up quite a few places!

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This weekend we have been at Silverstone, a classic track but one that has undergone a facelift for this season with new sections on the second half of the lap.

As usual there were plenty of interesting technical updates on the cars, with teams catching up on the trends of the season and adding either exhaust blown diffusers or drag reducing F Duct rear wings, or in the case of Williams, both.

Following on from the rush of exhaust blown diffusers we saw coming onto the cars in Valencia, McLaren had been working towards Germany but fast tracked the update and brought theirs to Silverstone for testing in Friday practice. It was the main feature of a major upgrade package, along with a new front wing.

The system means that the exhaust outlets need to be placed lower near the floor of the car and this causes some problems with overheating the rear suspension, if you are not careful.

Red Bull pioneered the technology and has really maximised it. They blow the exhaust gas through a slot which energises the airflow through the diffuser. It is this slot which the Red Bull mechanics are so keen for people not to see when the car is on the grid. But this is a bit of a pointless exercise, as teams have photographers taking digital images of the cars as they drive down the pit lane!

One of Red Bull’s secrets is a setting on the Renault engine for use on the final crucial lap in qualifying, whereby the ignition is retarded on the over-run, which maintains exhaust gas pressure even when the driver lifts off the throttle. This maintains the performance of the blown diffuser and keeps the downforce up when it’s most needed. It thus avoids the main problem of an exhaust blown diffuser whereby when a driver lifts off the throttle for a corner, the downforce goes missing when you most need it and the rear stability changes.

It’s not something you can do for more than a lap or two as the temperatures go sky high, which damages the engine, but it gives that vital fraction of a second which keeps Red Bull ahead of the rest in qualifying.

But one of the problems with running the exhausts low is that the components at the back of the car get very hot. McLaren’s lower wishbone featured a wide insulating cover to prevent overheating. The side sections of the diffuser featured an upper insulating plate, and underneath and they were painted with an insulating coating. But these precautions didn’t prevent the diffuser slightly changing shape due to the high temperatures, and this caused some rear end instability. So the diffuser was dropped for this weekend and McLaren had a rush on to balance the car with the new front wing but without the rear end package.

Their performance in the race on Sunday was quite remarkable given how much work there was to do after Friday’s problems.

Red Bull Front wing

The standard wing Webber qualified and raced with

The most talked about technical story of the weekend was the decision by the Red Bull team to use its new front wing on one car only, that of Sebastian Vettel. The team brought two of the new units to Silverstone, but the one on Vettel’s car broke a mounting during Saturday morning practice. So the team decided to take the wing off Webber’s car and put it on Vettel’s car for qualifying and the race, which angered Webber.

Vettel’s wing on the Silverstone grid

The pair had been doing comparison tests during practice and the team says that Webber and his engineer were not sold on the new wing by the time the decision was taken. The new wing has two main visible differences; it has a double slot on the side of the end plate and the horizontal plate at the outer edge of the wing is also double.

Ferrari updates

Ferrari brought an update to its rear suspension at Silverstone, to cope better with the overheating issue caused by the blown diffuser.

Increasingly the teams use Friday as a test session for new components and if they perform well they may continue on the car for the rest of the weekend, otherwise they may be taken off and used again at a subsequent event once some refinement has taken place.

On Friday, for example, Ferrari did a comparison run of the two cars with Massa using the drag reducing rear wing in the morning and Alonso using it in the afternoon. It was decided from that test to use the F Duct wing for the remainder of the weekend and Alonso managed to qualify third on the grid with it.

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The European Grand Prix at Valencia will be remembered for the enormous accident suffered by Mark Webber from which he mercifully walked away. But it was also another race where some vital decisions were taken in the heat of the moment, which shaped the outcome, especially when Webber’s accident triggered a safety car.

There were some important decisions to be made in qualifying, with a tricky one as to which tyre to use. There wasn’t much to choose between them and some people found that the hard tyre was fast on the second lap, but the soft was also faster for some on its second lap.

What was interesting was that having shown well in the first part of qualifying, some teams went backwards in Q3. The increasing heat made some teams struggle, including Renault, Mercedes and Force India, while Red Bull and Williams gained.

One interesting observation is that Red Bull has a setting on the engine, whereby the ignition is retarded on the over run, which maintains exhaust gas pressure even when the driver lifts off the throttle. This maintains the performance of the blown diffuser and keeps the downforce up when it’s most needed. It’s not something you can do for more than a lap or two as it damages the engine, but it gives that vital fraction of a second which keeps Red Bull ahead of the rest in qualifying.

Webber’s accident happened early in the race, lap nine, and for the drivers who started the race on the soft tyre, which was all of the top ten runners, it provided an opportunity to switch to the hard tyre for the rest of the race.

It was an inconvenience for the runners who started on the hard tyre, such as Michael Schumacher, because it inclined him into stopping earlier than the ideal for the soft tyre, which he would then try to take to the finish – a big ask. More of Schumacher in a moment.

It was obvious to all teams as soon as they saw the images of Webber’s car in the air, that a safety car was inevitable.

At this stage it was all about where your car was on the circuit and whether it was possible to pit quickly, before the safety car came out and get back out on track again. Regrettably for the other runners, the safety car did not manage to pick up the race leader, Sebastian Vettel and this was to have a major influence on what happened next. Vettel and Lewis Hamilton were able to get away and it spoiled the race.

Hamilton, who was second at the time, reached the safety car line at the same time as the safety car crossed it and passed the safety car, which is against the rules. He received a drive through penalty for this, but it would turn out to be only a time penalty, as he gained the advantage of a clear lap while the safety car held up all the cars behind him in which to change his damaged front wing. Even better for Hamilton, Kamui Kobayashi, who started 18th on the hard tyre, decided not to pit at all and ended up the car behind Hamilton at the restart, So as he held up the field, Hamilton was able to build enough of a margin to serve his penalty without losing a position.

The two Ferrari’s were caught out by the circumstances. They were the first cars picked up by the safety car. So they lost places to the cars behind them on the road, who were able to pit immediately. The Ferraris had to follow the safety car around until they were past the Webber crash site at which point they were waved through.

Robert Kubica was the first car to get into the pits, followed by Jenson Button and Rubens Barrichello. Adrian Sutil benefited from this too.

Michael Schumacher was also caught out by the position of the safety car. He pitted and was held at the pit lane exit, because the safety car was coming through, although Mercedes argue that Schumacher could have been safely released and that the red line was lit prematurely.

Schumacher’s choice was either to switch to soft tyres then, expecting the track to improve as the race went on and therefore be kinder to the tyres, or to do a Kobayashi and stay out. But he would have had to take the soft tyre at some point. Kobayashi delayed it to the end and then showed that on a new set of tyres, he was able to attack and make up places. Schumacher could have done the same, would have run third for most of the race, and as his car is faster than a Sauber, he would have built enough of a gap that he would lose fewer places when his inevitable tyre stop came.

This was after all the strategy, which he had intended to do, by starting on the hard tyre. So the safety car, and the fact that they had already pitted Rosberg so there was no need to queue the cars up, made them take a gamble which failed to pay off almost immediately because he couldn’t get out of the pits. He lost 16 places as a result of being held in the pit lane. Kobayashi’s result shows that Schumacher could perhaps have finished in the top six.

Valencia was the first time this season that we have seen cars queuing up in the pits under the new safety car rules. Two drivers who lost a lot by queuing were Felipe Massa and Tonio Liuzzi. Apart from the five or six additional seconds, they lost track positions too. Massa was fourth before the safety car, 17th afterwards. Speaking to engineers, it seems that in light of what happened, the decision to queue in that situation is being reviewed and we may not see that again with the current safety car rules. Probably we would only see it if the track was wet and doing an extra lap would be far slower.

Part of the reason why so many places were lost is because the field spread in Valencia is not that big, so after nine or ten laps the cars are still quite bunched up, which does not create the gaps for cars to slot back into,

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Blown diffusers explained

This weekend’s European Grand Prix at Valencia is a significant event in the story of the season from a technical point of view as it was the race where many teams unveiled a device which copies the Red Bull’s “blown diffuser”.

Last year three teams started the season with a double diffuser and, after establishing the legality of it, the rest of the field was forced to follow suit, including Red Bull. This year’s “must haves” so far have been the McLaren F Duct wing and now the blown diffuser. Red Bull is the pioneer and Mercedes, Ferrari and Renault have followed them this weekend. McLaren and Force India are due to follow at Silverstone.

On the grid this season the Red Bull mechanics have been carefully masking the diffuser from view. Although they do have something interesting to hide, in F1 this is often a bluff, indicating that the most interesting part of the car is somewhere else, but they want you to focus on the diffuser!

A blown diffuser is basically a way of using the exhaust gases to interact with the diffuser, which sits at the back of the car at the end of the floor. There are two main purposes for this;

* to try to move the wake from the rear wheels outwards where it will cause less disturbance

* to re-energise the low pressure air at the very back of the diffuser to create more rear downforce.

Rear downforce is important for driver confidence, if the driver feels good rear end stability he will push harder, so the gain on the stopwatch from this kind of development is often not what a simulator tells you it will be, but what the driver actually delivers from it.

The irony is that blown diffuser is not a new concept, unlike F Duct wings or double diffusers. Renault had one in the early 1980s, Frank Dernie put one on the Williams of Nigel Mansell in the mid 1980s and they were common from 1985 onwards. Adrian Newey’s team at Red Bull didn’t invent it, they revived it. The early ones were crude in that the rear of the car often became less stable when the driver lifted off the throttle. Everyone knows this but more about the science now.

They went out of the sport in the mid 1990s due to a change of wording in the rules, but Newey felt that the current rules would make it worth trying again.

The blown element operates independently of the “double” element of the diffuser and whereas double diffusers are banned from next season, the blown diffuser is here to stay.

The Ferrari’s exhaust exits have been moved from the high exit in the top bodywork, which they pioneered in the early 2000s, to the low exit near the floor to feed the diffuser. They stop slightly shorter than the Red Bull ones.

Low exhausts heat everything up in the area behind them and there is a risk here. Less widely reported, there was a new Ferrari gearbox this weekend, only on Felipe Massa’s car, designed to raise the pick-up points of the lower wishbone, in order to keep it away from the hot gases from the low exhausts.

Keeping temperatures under control is important and it was intersting to see a series of red stripes on the rear side section of the Ferrari diffuser. These stripes are of a special paint, which changes its colour in relation to the different temperature of the surface where its applied. In this way the Ferrari engineers could see which part of the diffuser reaches too high a temperature due to the hot gases directly blowing on them.

Ferrari’s update also includes new cooling ideas in the radiators and bodywork for the series of warm weather races coming up in the summer, as they have had problems with the engines in hot countries earlier this season.

This is an important update for Ferrari, who started the season as the pace setters but then lost ground as they got bogged down with developing the F Duct rear wing at the cost of other avenues. Meanwhile McLaren, Mercedes and Renault all stole a march on them.

Renault also had significant upgrades, including the blown diffuser. In this illustration by our technical artist Paolo Filisetti, you can see the old style high exhausts at the top and the new low style ones at the bottom.

Renault continue to push hard, they brought the 22nd iteration of their front wing to Valencia, the ninth race of the season.

And finally Lotus had a good qualifying session in Valencia, with Jarno Trulli the fastest of the new teams, increasing the margin over the other new teams to 1.4 seconds. That said the gap to the slowest of the established teams, ironically Kobayashi’s Sauber, had also grown to over a second.

One key update for Lotus this weekend was a new front wing solution, which owes a lot to design ideas on last year’s Toyota. Many of the engineers at Lotus came from Toyota so this is not altogether surprising.

Re-printed from James Allen on F1 - The official website.