Technical review: Belgian Grand Prix

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Lewis Hamilton, McLaren, Spa-Francorchamps, 2010

Superficially, Spa was a bit of a head-scratcher. Four weeks earlier, in Hungary, McLaren were 1.3 seconds off the pace of Red Bull.

How was the Woking-based outfit able to more than claw back that deficit at Belgium – despite having had a mandatory two-week factory shut down between the races?

The circuit

As a circuit Spa is the antithesis of the Hungaroring. Take a look at a map of the Budapest track and you’ll see lots of corners and few straights (which is why there is always so little overtaking). Many of its bends are fourth and fifth gear turns and, as downforce squares with speed, it plays to the RB6’s strengths.

Ah, you might say, but why wasn’t the RB6 pulling out half a second in Spa’s sector two where there are several quick corners? As Red Bull never fails to remind us it has a power deficit to McLaren and Ferrari and, in Belgium, significant overtaking opportunities is into the bus stop in sector three and up the hill after Eau Rouge in sector one.

Therefore high-speed / low drag is order of the day. In order to keep the silver cars at bay Red Bull took a significant amount of wing off, which compromised grip in the twisty middle sector.

Flexi wings

Mark Webber, Red Bull, Spa-Francorchamps, 2010

Spa also saw the introduction of a more stringent test to try to reduce flex in front wings.

Although Christian Horner denied having to alter the front wing for Spa he is no position to claim otherwise or he would be admitting rival teams had successfully identified one of their advantages.

McLaren analysts were reportedly much happier with the reduced amount of flex on Red Bull’s wing. However, Red Bull did bring a different wing to Spa – it had a smaller cascades for reduced drag (and downforce), so it might be the lower downforce that is causing it to flex less.

With the next race, Monza, being another ultra-low downforce track, and with the advent of a new floor deflection test, it won’t be until Singapore that we know whether the new load tests have had cut Red Bull’s performance advantage.

Although the mystery of the flexing front wing is no closer to being solved, it seems as though the most plausible theory is that Red Bull lay the carbon fibre composite in a specific (and different) manner that leads to non-linear deflection (in other words the degree of deflection varies to some power of downforce) as well as fiddling with the front splitter and floor to allow the front section to dive.

The onboard video of the Button/Vettel crash from the Red Bull shows the front wing moving as the RB6 pulls out of Button’s wake. The endplates move visibly as the higher airflow affects the wing causing a roll moment. There is a belief among some in the paddock that the flex wing could have contributed to the accident.

McLaren diffuser

McLaren’s struggles with its blown floor seem to have been mostly resolved. On its introduction in Silverstone it had to be replaced with the so-called T2 (old) floor. In Germany, with modifications, the floor seemed to work better, but was still obviously problematic.

It is only with a couple more weeks of development that the kinks have been ironed out.


Fernando Alonso, Ferrari, Spa-Francorchamps, 2010

Surprisingly, Ferrari were not on the leaders’ pace in Spa.

Ferrari ran two different rear wings: Fernando Alonso preferred an older, higher-downforce design whereas Felipe Massa went for a new version with no blown slot, a shallower main plane and three curved gills in the end plates. Alonso was banking on more rain on race day where more downforce makes the car faster on a slippery surface.

Ferrari also introduced a revised diffuser with a larger top deck that integrates more with the rear wing (a la McLaren). Looking from a 45 degree angle, from the rear of the car it is clear that the upper diffuser exit is significantly larger.

There are two longitudinal fences running either side of the car centre line (four in total) supporting this open-vented structure and to act as turning vane for air under the floor. As McLaren has discovered having a over-sized diffuser exit can result in super-sensitive ride heights. Keep an eye out for whether Ferrari run such an open diffuser on the bumps of Singapore or Brazil.


Jenson Button, McLaren, Spa-Francorchamps, 2010

There were few obvious changes to the MP4-25 at Spa. The cascade on the front wing was truncated to the inward vertical fence (rather than extending further inwards to the car centre line), and there also an additional inlet carved into the endplate. The smaller cascade cuts drag and allows the car to attain a higher top speed through sectors one and three. The endplate changes were most likely to optimise the airflow around the tyres and to the sidepods, which in turn has a knock-on effect to the floor and diffuser.

McLaren continues to tweak its exhaust-blown diffuser. Unfortunately many of its changes can’t be picked out in photographs (the performance of the car speaks for itself) although it was possible to spot a second slot in the floor in front of the rear tyres. This allows high energy air to seep under the car and around the tyre. This, in theory, keeps airflow attached behind the tyres increasing the efficiency of the entire floor.

Lewis Hamilton, McLaren, Spa-Francorchamps, 2010

It also appears that McLaren has been playing with its engine mapping settings to try to replicate Red Bull’s over-drive setting. Through the corners the engine on both McLarens sound rougher. This is probably a result of altering the settings to burn air/fuel mixture in the exhaust to maintain a (more constant) flow of exhaust gas to the diffuser. Red Bull allegedly only runs this setting in qualifying whereas the McLaren engine sounded rough for the whole race.

Hamilton reverted to an earlier version of the front wing (top image) having run the new one on practice (adjacent images).


Vitaly Petrov, Renault, Spa-Francorchamps, 2010

Renault brought its much trumpeted F-duct to Spa. It is actually the second generation F-duct, the first having been canned before it reached production after initial tests showed it wasn’t particularly effective.

It was a good decision as Renault was immediately competitive at Spa despite having an alleged horsepower deficit due to its engine. The team claims the F-duct was worth 0.5s a lap and Kubica’s second row starting position backed up that claim – he might have started on the front row without his fuel feed problem in Q3.

The solution itself is innovative. The F-duct is like a fluid transistor which requires the driver to manually switch it on (by manipulating air pressure). Usually teams route the duct through a hole in the monocoque to the driver’s hand. When the driver places his hand over the switch is ‘on’ and air from the F-duct disrupts the standard rear wing airflow, which is what causes downforce (and drag) to drop away.

The problem for teams like Renault, who are trying to retro-fit an F-duct to a car that was designed without one, is their chassis was homologated at the start of the year. They have to think laterally to design in the F-duct because they can’t cut a new hole in the chassis.

Renault has two inlets either side of the airbox to suck in air and stall the rear wing. When the duct is ‘on’ air takes the upper route and there is an outlet feeding the main plane (rather the the flap, which is Red Bull and Ferrari’s preference). When ‘off’ the air blows harmlessly between the beam and rear wing.

To switch the f-duct on a driver activated control duct is required and this weaves from from the drivers headrest and into the cockpit to exit by the steering wheel. By placing his hand over the control duct the air pressure in the switch changes moving the duct to ‘on’ and stalling the rear wing.

Red Bull

As discussed above Red Bull ran a revised front wing which, like McLaren’s, had modified cascades for reduced drag.

The Milton Keynes-based outfit ran a low drag beam wing in practice but it was discarded for qualifying and the race. There were also reports that Red Bull altered the fixing for the brake ducts.


In my last technical review I gave a short primer about how installing an EBD involved complex re-routing of the exhausts to make sure the pressure waves exiting the exhausts were maximised engine power. I made mention that designers would need to tune the length of each exhaust leading into the collector to optimise this pressure distribution. Unfortunately, as a couple of readers pointed out, that isn’t right.

Variable length exhausts are of course illegal in F1. However, in implementing the EBD teams do definitely take a lot of care re-routing the exhaust structure to make sure the pressure wave behind the exhaust is optimised for engine torque and peak power – they just can’t use variable length exhausts to do so. Apologies for the error.


And now on to to Monza where top speed is all that matters. Based on what we saw at Spa expect McLaren to be quick. Ferrari should be competitive too, but, as at Spa, Red Bull may struggle a little.

The issue is that engine power rather than driveability is the key factor (Mercedes power trumps Renault driveability) and Monza is perhaps the least important for driveability.

Also the RB6 is a downforce machine and you want as little as possible, within reason, at Monza. The theory is that Red Bull can’t lose downforce fast enough and will struggle. Expect the Italian Grand Prix to be only the second time this year when a Newey machine isn’t on pole.

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38 comments on “Technical review: Belgian Grand Prix”

  1. I am still surprised Webber managed Pole position in Spa. I wouldn’t write them off for Monza. Renault managed somehow to be very quick on straights in SPA, I guess Red Bull could manage the same.

    Of course, I hope not, for the sake of the championship!

    1. The only reason Webber had pole, was that the weather robbed the others for a good second run.

      1. Kubica had only one run and he did great with a Renault Engine. Plus Webber was only 20 seconds before But + Ham on the finish line.

        1. They were out on scrubbed tires for the first runs, putting on new for the final run, which failed because of the rain. Whitmarsh was amazed that they improved at all.

          They ran just enough later for the first few corners to get wet. Even the commentators on the danish 3 Plus (which are normally not too bright), saw that it was perfectly timed as the track got wet just after he passed.

          1. Hamilton almost improved on Webber’s time in the wet, and Kubica came darn close with a fuel pick up problem. If it had stayed dry and Kubica had had no fuel problem, they might well have both qualified ahead of Webber.

  2. “As Red Bull never fails to remind us it has a power deficit to McLaren and Ferrari and, in Belgium, significant overtaking opportunities is into the bus stop in sector three and up the hill after Eau Rouge in sector one.”

    And yet 2 Renault powered cars finished on the podium and started from 3 of the top 4 positions on the grid at this power circuit. As I have pointed out before, both Rubens Barrichello and Heikki Kovalainen said in preseason that they felt their new Cosworth engines were better in many ways to the Mercedes engines they used the year before. The Cosworth is apparently more “drivable”, with power available over a broader rev range. I imagine that the Renault engine must have its own strenghts compared to the Mercedes and Ferrari (cooling is apparently one and I imagine that torque, where Renault engines have always been strong, is another). But as you said, Monza wil be an out and out power circuit where these other factors don’t matter as much.

    Red Bull made their choice (having had a Ferrari engine supply in the past and, reportedly, a chance to switch to Mercedes this year) and they must stick to it.

    Great read as always John!

    1. Geemac : You manage to give my point in a better documented way, thanks !

      And of course, thank you John for the article

    2. I’m not sure there was a real “chance” for Red Bull to get the merc-engine? They tried but they didn’t get it, right?

  3. Another problem I foresee for Red Bull is the run down to the Rettifilo is so long. As well as being in danger of not even making the front row, they could be sitting ducks on the way to Turn 1 too.

    It won’t be all bad. Their performance in Monaco showed they have good traction, so that will help them a bit out of the chicanes, and there are a few fast sweeps where they might gain a hundredth here, and tenth there. But Curva Grande is always flat out, and there are three massive straights they will lose out on big-time.

    I might even put a bet on no Red Bull hitting the podium.

    1. I just hope Vettel bins it again, but gets Webber or at least Alonso this time.

  4. Another load of deep insights. Thanks for correcting/clearing the exhaust length issue. Keep up the good work John!

    1. The exhaust length does have to be tuned, but that is done with the length of each individual exhaust pipe to the collector and is a fixed length. It is critical that each pipe be the same length, as essentially an acoustic wave is set up to resonate at specific RPM, generating a negative pressure (or at least a lesser pressure) at the exhaust valve, aiding exhaust gas flow. So it is critical that the pipe routing be correct so that the lengths are the same. It’s too bad that variable inlet and exhaust lengths are not allowed; I feel that F1 has dumbed down engine technology too much, leaving very little room for innovation.

  5. I think that Renault’s Kubica and Petrov will be quick.

  6. Great read John!

    I’m still picking a good red bull showing. Everyone thought they would be a no show at Spa, and they hit the podium. While i understand that Monza is a different track altogether, i don’t think we can expect a poor showing.

    While the RB6 is a downforce machine as John mentioned, It wouldn’t surprise me in the slightest if Mr Newey pulled a surprise out of the bag and RB6 was still in the top 5.

  7. Hell its unbelievable and downright dangerous how much vettel’s wing twisted on the onboard collision fottage!

  8. There is a belief among “some in the paddock” that the flex wing contributed to the Button/Vettel wreck? Hmmmm, who could we be talking about? Maybe someone at Hispania? ;) Seriously, I love the website, Keith, and I’m glad the McLaren boys respect you enough to give you some scoops, but let’s not get carried away with the source protection.

    1. I didn’t write the article – John did.

      1. Two engineers I spoke to suggested that such a change will create quite a lot of roll — perhaps not enough to cause a crash but certainly enough to affect the handling of the car

        1. MouseNightshirt
          6th September 2010, 18:49

          …which when added to a car already on the limit of stability by a sudden swerve may contribute to the car going over the edge.

  9. Thanks for this article Keith, very informative.

    I think there is a mistake on Renault’s fourth paragraph:

    …retro-fit an F-duct THE a car that was designed…

    1. Fixed, thanks macca.

  10. nice writeup John Thanks.

    you might like to also let us know a little bit about how the RB6 was banging the rev counter along the straight, it seamed as if they had chosen the wrong gear or something.

    interesting about RB6 front wing, i did notice that in slow motion on the BBC broadcast going over the curb it wobbled a lot, the two mounts that connect the front wing to the nose was were it was moving this time, which was new to me.
    this footage may have not been shown in some countries unless you have no adds while watching it, as it seamed like it was an intermission break without the commentators talking.

  11. Any chance someone can provide some stills of the Vettel wing pre-killing Button? I haven’t been able to watch the video since I’m in the States. I’m just curious how bad it looks.

    Great article John.

      1. Thanks for the link. I hadn’t rechecked after the youtube video was removed.

        Looking at the video, I think it makes the car unstable. Should be enough for one wheel to lose traction while keeping the other down and boom.

  12. I made an animation of Vettel’s front wing when standing on the grid and at the end of Kemmel (where he was on the limiter). There was actually quite some flex still:

    1. Wow, what strikes me most is how much narrower and taller the front tires are at high speed as opposed to stopped on the grid.

      The wing is definitely still flexing a fair amount though…

  13. You can’t really spot flexing from the onboard shots though, too bad FOM didn’t do their slow-mo ‘front wing analysis’ shots at Spa. Maybe because there wasn’t much flexing this time so they didn’t bother.

    1. like i said there was some shots of the RB6 going over the Curb and man was that wing swing from side to side not just up and down on the ends,
      this time it was the two mountings that fix the wing to the nose of the car that were swaying from side to side.
      our BBC Live broadcast in NZ is an uninterrupted feed through Sky TV and i remember no one talking as if it was a commercial break, so not sure how many other saw this footage.

  14. Thanks for the article John, much appreciated.
    But I would like to highlight the fact that, unlike what you have written,

    “Ah, you might say, but why wasn’t the RB6 pulling out half a second in Spa’s sector two where there are several quick corners?”

    the RBRs actually were half a second quicker than anyone else in Sector 2, at least in qualifying, according to to

    Sector #2
    Pos No Driver Time
    1 5 Sebastian Vettel 45.493
    2 6 Mark Webber 45.608
    3 2 Lewis Hamilton 45.915
    4 9 Rubens Barrichello 46.052
    5 1 Jenson Button 46.055

    Therefore the downforce advantage enjoyed by Red Bull is still substantial.

    Your considerations on McLaren blown floor evolution are convincing to me, and as a Ham supporter I really hope it is going to feel at least part of the aerodynamic performance gap to RBR.

    Honestly I didn’t expected McLaren MP4-25 to be so strong in Belgium neither so poor in Hungary, simply considering the fact that in 2009 the opposite situation was the opposite: the just reviewed MP4-24 showed in 2009 a great pace in Hungary and a poor pace in Belgium which is, as you correctly states, “antithesis of the Hungaroring”.
    Assuming that McLaren is going to be at top in Monza as per last year (and as everyone now seems to believe), how do you expect McLaren to be in Singapore, where Lewis was really strong last year?

    1. The MP4-24 was very good with mechanical grip and traction out of corners. The MP4-25 has sacrificed that for stability around the fast corners.

    2. @manuel f , hamilton was 0.171s slower than webber through middle sector on race trim .

      1. Thanks, John. Especially for the explnation of the exhaust geometry.

        Regarding the riddle of how slow RBR is in a straight line compared to the factory team, we might consider the exhaust. Do they have the same manifolds as the yellow cars? If RBR have compromised their geometry to feed the diffuser, we may have some of the reason why they allegedly lack power.

  15. Thanks for the article John. Very informative as usual.

  16. I’ve never posted before but have been a long time reader of the site and think Keith and co do a superb job, so just wanted to show my appreciation.

    Are the McLarens really expected to dominate in Monza? I’ve heard this before but only to see the Red Bulls nick another pole. Obviously the straight line speed will play massively in their favour, but for someone who isn’t too clued up on all the technical side of things, will RB’s superior downforce not help in the high speed Monza turns? Or will the McLaren be superior through the bends as well?

    1. Monza is all about low drag and high top speed. It is most similar to Spa and Montreal (bit more extreme in its requirements) — McL won on both tracks.

      The only way McL will be uncompetitive is if another team has a super low-downforce package (ala Force India last year). From what we’ve seen it is unlikely but you never know of course.

  17. Thanks for your comments guys

  18. I think Kubica might have a shot at winning this and petrov should do well its going to be good for the renaults

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