Technical review: Italian Grand Prix

Jenson Button, McLaren, Monza, 2010

Guest writer John Beamer looks at the technical developments at the Italian Grand Prix.

The fine balance involved in setting up a Formula 1 car was a major talking point at Monza as never before.

It all revolved around the decisions teams had to make about whether to run their F-ducts or not – and the fascinating split strategies employed by McLaren.

To duct or not to duct

The question going into the race was whether to use an F-duct or not?

First, a quick recap on how the device works. There are many implementations but McLaren were the pioneers. Look at the nose of the MP4-25 and you?ll see a raised inlet by the ??F? of Vodafone ?ǣ hence the moniker F-duct. Internally, McLaren calls the device the RW80.

Air enters the duct and routes thought a hole in the chassis where it exits into the cockpit. When the driver chooses he can close the cockpit exit, forcing air through the shark fin cover into a rear wing slot, which creates turbulent air and cuts downforce (disturbing air underneath the wing). Downforce induces drag, so this loss of downforce cuts drag allowing higher top speeds.

This comes at the cost of aerodynamic efficiency (measured as the ratio of downforce to drag). But that isn?t an important factor when flying down Monza’s 340kph straights.

Unfortunately for McLaren’s rivals chassis are homologated at the start of the season which means the neat solution seen on the MP4-25 is difficult to replicate. The most common and effective alternative is a ??fluid switch? system, which is what Red Bull use.

Their inlet duct is fed from the airbox and splits in two ?ǣ the lower section blows harmlessly under the rear wing while the second (upper section), when activated, blows air at the rear wing causing stall. A third (control) duct routes into the cockpit that allows the driver to activate the switch.

When ??off? air will blow into the cockpit through this third duct; when ??on? the air pressure inside the switch changes forcing air into the upper section which stalls the rear wing.

The McLaren conundrum

Jenson Button, McLaren, Monza, 2010

Jenson Button, McLaren, Monza, 2010

McLaren offered their drivers two striking different aerodynamic options. Surprisingly, they each chose differently: Button preferred the higher downforce wing with F-duct and Hamilton opted for a traditional Monza-style super-skinny rear wing.

Button?s car wasn?t much different from what was raced at Spa – the rear wing was identical. Hamilton?s car had no F-duct or shark fin. This confirms McLaren?s view is that the fin is aerodynamically marginal – its only purpose on the MP4-25 is to carry the F-duct to the rear wing.

A closer look at Hamilton?s rear wing shows that McLaren simply updated last year?s design. It was a slimline two-piece wing with the flap attached to the end plate with three raised gills which increase its efficiency.

Lewis Hamilton, McLaren, Monza, 2010

Lewis Hamilton, McLaren, Monza, 2010

The difference in top speed between the two set-ups was massive. Hamilton clocked 345kph (214.3mph) through the speed trap to Button?s 330kph. However, Button could carry more speed through the corners, particularly the Lesmo bends, to reduce the deficit and arrive at an almost identical lap time.

One reason why Button opted to carry more downforce was that it was easier on his tyres. Graining, which is when the rubber forms balls on the tyre surface reducing grip (think of it as having a film of fluid between tyre and tarmac), is less likely if a car has more downforce, as the tyres slide less. However the additional drag meant Button had to carry more fuel causing him to brake fractionally earlier into the corners and making acceleration slightly slower.

Hamilton mooted that Button had chosen the better set-up after being out-qualified by his team mate. His first-lap crash meant we didn’t get to compare the two solutions over a race distance.

Hamilton?s final qualifying lap was compromised because he got too close to Webber not because of car set-up. Yes, the car slides around more but Lewis had shown all weekend there wasn?t a hair?s breadth between the two set-ups.

And in the race having an extra 15kph of top line speed, coupled with less fuel, would have been pretty handy to bag an overtake or two.

Ferrari

Fernando Alonso, Ferrari, Monza, 2010

Fernando Alonso, Ferrari, Monza, 2010

Through the speed trap the F10 topped out at 338kph – the same as the F60 managed the year before. The difference in lap time was half a second, which shows the benefit of the F-duct (although part of that lap gain is due to increased aerodynamic efficiency as part of normal development).

Ferrari bought two rear wings to Monza: the version that Massa ran at Spa and one with lower downforce ?ǣ both cars raced the latter.

This featured a smaller main element and had no endplate gills in addition to a smaller F-duct channel. The slimmer wing required a lower volume of air to stall, hence the smaller F-duct outlet.

Fernando Alonso, Ferrari, Monza, 2010

Fernando Alonso, Ferrari, Monza, 2010

The Scuderia also introduced a new front wing featuring an almost flat main plane and a shallower flap/cascade combination. Together these produce a more aerodynamically efficient device ?ǣ perfect for Monza.

A close look at the Ferrari endplates shows a lack of slot gaps like on the McLaren or Red Bull.

The slot gap is to allow air to bleed from outer part of the endplate underneath the plane and flap. This air carries more energy so keeps flow underneath the rear wing attached for more downforce. When running a shallow wing, like Ferrari did, the slot gaps hurt performance because airflow generally remains attached anyway and the slots just add drag.

Renault

Vitaly Petrov, Renault, Monza, 2010

Vitaly Petrov, Renault, Monza, 2010

After the success of Spa, where the team successfully introduced its F-duct, it was no surprise the device was retained for Monza.

For Monza Renault introduced another version of its much-developed front wing. The fiendishly complex endplate was simplified, but still had more detail than most other teams?. And although the wing retained the usual double flap (three elements in total) the cascade on the inner part of the endplate was deleted.

The upper flap had a ??V? etched into it. Air flowing over the front wing would be pulled under at the ??V? creating a vortex. This vortex has rotational energy that is directed towards the tyres (possibly the brakes) or floor to improve either brake cooling or downstream aero performance.

The remaining teams

Mark Webber, Red Bull, Monza, 2010

Mark Webber, Red Bull, Monza, 2010

Among the big teams Red Bull were notable for an absence of major aerodynamic upgrades. The Milton Keynes-based outfit ran a medium/low downforce package similar to what it raced at Spa, but it was almost as if the team passed on Monza in the knowledge it would be quick at the remaining circuits.

Toro Rosso bought its most significant upgrade of the year to Monza and debuted both an F-duct and a blown floor.

The blown floor was very similar to other teams? versions with exhausts exiting from low down below the back of the sidepod undercut. The gas blows inside the rear tyre over the diffuser and does not blow into the diffuser ?ǣ that will likely come later, maybe next year for Toro Rosso.

The blown floor was raced but F-duct proved far more problematic. Point blank it didn?t work ?ǣ the device was effective at shedding drag but couldn?t retain downforce when it was ??off?. The design is similar to that of sister outfit Red Bull.

Force India and Mercedes both opted to race without F-ducts – an indication that their respective devices aren?t as effective as other teams?.

Mercedes first introduced a passive system and is the only established team that doesn?t run a shark fin to pipe stall the rear wing. Instead the system routes through the rear wing endplate. In recent races Mercedes has introduced an active driver-controlled device but it wasn?t raced at Monza.

Sakon Yamamoto, HRT, Monza, 2010

Sakon Yamamoto, HRT, Monza, 2010

HRT seldom get a mention in the technical review but it was the only team not to bring a lower downforce package to Monza ?ǣ both Virgin and Lotus brought different specification wings. It gives an indication just how much the team is struggling for funds.

The team ratcheted the wings down to the lowest permissible angle and made do. In one sense if you?re at the back of the grid it doesn?t matter what wings are raced.

Splitters

Monza saw the advent of the more stringent splitter deflection test. A 100kg weight can now be placed at any point along the front splitter rather than just at the central section (which is allowed to deflect by 5mm). This stops any lateral flex that may allow the front of the car to sink especially when cornering.

In addition articulated joints are outlawed and teams must use a 1m plank leading up to the splitter. This is to prevent a dual splitter which may be hinged with an articulated joint.

Before the introduction of the new tests most teams had a central stay attached to the chassis to ensure compliance. The stricter test saw teams employ a variety of solutions. Red Bull were publicly keen to show that the changes didn?t affect them and their splitter fixing was visually unchanged. However, Red Bull failed the load test on Friday by a small margin, then passed the following day.

Counter-intuitively McLaren deleted its central fixing opting to strengthen the splitter. This suggests that the MP4-25?s splitter may have had some lateral flex. Monza isn?t a circuit where a hinged splitter will have a massive effect of performance.

Mercedes produced the most visually robust solution with an inverted ??V-style? joint to prevent any part of the splitter flexing. Although adding strength this disrupts airflow over the splitter to the floor and sidepods ?ǣ Mercedes will likely adopt a neater solution for future races.

Singapore

The European season has now finished and there are now only five fly-away races left. Singapore is next up and we can expect it to be the race where most teams bring their last major upgrade before dedicating most of their resources to the upcoming season. Red Bull, McLaren and Ferrari are all due significant upgrades.

After two low downforce tracks (Spa and Monza) designers have had plenty of time in the wind tunnel to perfect their latest upgrades. However, given the closeness of the championship don?t be surprised to see the top constructors continue to develop aggressively up to Brazil, which will likely compromise the beginning part of their 2011 campaigns. Ferrari, for instance, have reallocated resource back to the F10 after Alonso?s victory last weekend.

Singapore is a classic street track ?ǣ it?s tight and bumpy and requires oodles of downforce. It should play to the strength of the RB6. The McLaren is uneven over the bumps and doesn?t relish ??point and squirt? corners as much as its rivals. However, McLaren will have upgrades to the blown diffuser and we should see whether the new front wing and deflection tests have curbed Red Bull?s speed.

Ferrari will be in the hunt too. The F10 rides the bumps well and performs exceptionally well under braking, which is important for Singapore where there are 23 medium/low speed corners. Come the end of the race we?ll have a good idea whether the five-horse race will continue to Abu Dhabi or whether Red Bull still has a comfortable performance margin on high-downforce tracks.

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Images ?? www.mclaren.com (1-3), Ferrari spa (4-5), Renault/LAT (6), Red Bull/Gett Images (7), Bridgestone/Ercole Colombo (8)

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43 comments on Technical review: Italian Grand Prix

  1. Thanks again for this piece, always my favorite of the racing week end.

    • Mr. Zing Zang said on 21st September 2010, 0:42

      I am sorry Keith but your contributor is lacking some details and wrong is some parts of his technical review again. I suggest getting a real engineer checking the correctness of these articles from now on.

      For instance, his description of workings of the F-duct is not correct. In fact, there is nobody outside of the actual F1-engineers and savy aerodynamicists who exactly knows the detailed mechanisms of how it works. Notice the RedBull has 4 openings for their F-duct as well not 3. The 4th opening is hidden in the roof of the radiator inlets.

  2. you have been a busy man John well done,

    i just hope McLaren have there blown diffuser working properly, and that the new reg’s sort out the flex’y wing rubbish.

    i see you mention the blown diffuser for next year, i thought i read some place that it is going to be band along with the F Duct next year, or is that the year 2013?

    • John Beamer (@john-beamer) said on 20th September 2010, 11:17

      blown diffuser is allowed next year … the double diffuser is banned which will reduce its efficacy but will be deployed nonetheless

      • I suppose that explains why it is worth the trouble for teams like Torro Rosso to bother.

        I also thought blowing exhaust gasses INTO the diffusor (as it should not have holes)would be banned next year, allowing only for blowing air over it.

  3. Is it specific for Monza that (for Mclaren) the shark fin has no use without the F-duct? Because otherwise I wonder why they (and other teams) were running it even before they had F-ducts.

    • Mclaren hasn’t ran the fin without the F-Duct or at least I don’t remember them doing so.

      Others have though.

    • Sush Meerkat said on 20th September 2010, 12:27

      The shark fin helps out with cornering stability apparently, a necessity in the days without Traction Control.

      Mike Gasgoyne of Lotus said when he first saw it he thought was to bring attention away from something else at the rear of the car, something possibly not in the spirit of the rules.

      • John Beamer (@john-beamer) said on 20th September 2010, 12:33

        Air hitting the fin in yaw is straightened over the rear wing for more downforce. Since it isn’t universal, and McLaren in particuarl only use it for the F-duct its benefit must be, at best, marginal. McLaren have tested it a few times sans f-duct but never raced it. I suspect it is very car specific and even then it is probably a marginal benefit. Be interesting to see how many teams retain it for next year.

        • Alastair said on 20th September 2010, 13:23

          Whatever the benefit, regardless how marginal it is, those shark fins are pig ugly. They don’t belong on an F1 car in my opinion. makes the cars look odd.

        • I think there might be one or two teams considering running something alike what Mercedes has to lower the airbox front exposure.

          Red Bull have been using shark fins for a long time and Ferrari and Renault as well.

          • US_Peter (@us_peter) said on 20th September 2010, 18:56

            Red Bull have been using shark fins for a long time and Ferrari and Renault as well.

            Arguably the most competitive cars on high downforce circuits. Maybe the other teams should take the hint.

          • John Beamer said on 20th September 2010, 21:15

            My understanding is that Mercedes air box solution is not legal next year but I could be wrong

  4. Great article, satisfies my inner anorak, whom I only let out on rare occasions!

    • Keith Collantine (@keithcollantine) said on 20th September 2010, 13:43

      “Satisfy your inner anorak” – could be a slogan for F1 Fanatic!

      • Could be? LOL. I thought it was!

        (P.S. Finally finished and edited that thing we discussed, and accidentally deleted it. Google map Toronto-Sudbury and see where I drove to and from today for work. Have notes to draw up electrical schematics for three of my designs here on my desk. Hopefully, Keith, I shall re-do it before the end of the season). andy

  5. Thanks again John.

    Unbelievably, McLaren could do with the MP4-24 at the moment it seems!

    Quite sad to hear HRT hadn’t got a low downforce-spec rear-wing for Monza – it really shouldn’t cost that much to make one. Not sure whether we’ll be seeing them in 2011 to be honest at this rate.

    • At least they have the race team in place (more or less) and have gathered very valuable data. Even if they have not been able to do very much with that this year. But it will come very handy to develop a car for next year. This year the car was not really worth the effort i suppose.

      They can be happy about the 14th spot Chandhok got in Australia, as it has kept them in front of Virgin for now.
      I am sure that even if the team would fold up, there would be a buyer out there (Villeneuve, Cypher, ART, Villedeprat, …)

      • US_Peter (@us_peter) said on 20th September 2010, 18:59

        That’s true. Arguably they’ve gathered the most valuable circuit data of any team, since their car has been the same all season. While other teams are developing their cars it’s hard to know what differences are from the circuit, and what differences are from the upgrades. For HRT they can eliminate the upgrade variable. They’ve made their car the “control group.”

        • dyslexicbunny said on 21st September 2010, 3:48

          Perhaps but I’m not quite convinced of that Peter. If they had the funding, they might do the modeling to help initially calibrate some performance tools but as soon as they change the vehicle, what then?

          Depending on how significant the modifications are for next year, this year’s data might even be meaningless.

          I’d like to start the rumor that Hyundai is looking to buy HRT. I have nothing to support it but it would be interesting to spread for kicks. I told a roommate and he got all interested and thought of the implications.

  6. Jackpolak said on 20th September 2010, 13:58

    Great peace, like usualy.
    However i’m not sure if Button had to brake a fraction earlier. he had more weight, but less speed, and more downforce on the other hand.

  7. Jackpolak said on 20th September 2010, 14:00

    i mean – great pice :)

  8. The more important technical aspect, according to my expert analysis, was the effect Button’s setup had on the cars behind him. For example, Alonso with ultra low downforce had to follow a car with probably the biggest dirty air profile on the circuit, combined with Alonso’s having less downforce meant Alonso would always exit the parabolica much too far behind to be able pass or take advantage of the top speed advantage. He never could. He had to pass in the pits! Button’s setup is why the Ferrari was never able to get close enough. The high corner speed, high downforce created the dirtiest airwash out there and top that of with an ultra low downforce Ferrari behind it, of course the Ferrari couldn’t get close enough to pass. It would have been a nightmare to drive the closer he got to the McLaren. So the fact that Button could use that high downforce, but then with this years ability to stall the rear wing some, compared to other years when history showed you needed the low downforce wings for sure, sounded like a good option to try.

    • Warren, im with you on this, i watched Alonso start to slid out as he got too close to Button halfway though the parabolica, and thought noway are you going to pass Button down the straight, as i was rooting for Button.
      i still cant believe they brought him in before Alonso, i just about turned the TV off because i could see what was going to happen before it did, just plain crazy call that was by his team.

      • John Beamer said on 20th September 2010, 21:18

        Not sure if that is a factor — following any f1 car is hard. The issue is that button just could carry much more speed through the parabolic than Alonso. That corner is super tough in a low downforce car as Lewis intimated

  9. It is remarkable that Ferrari brought a special one-off low-capacity F-Duct system, as well as a special front wing. Ferrari solved the set up conundrum McLaren had ahead of time by creating a compromise F-Duct, and thus gained an advantage. It was interesting though, that McLaren, with a plain vanilla skinny wing on Hamilton’s car was not much behind if at all.

    But it must have cost Ferrari a lot of time to develop this Monza F-Duct and I wonder if that was wise considering that this development will be of little or no use in the future races; and presumably RBR and McLaren have been cooking up big upgrades for Singapore and beyond.

    Another interesting aspect to the race was tires. If part of Button’s theory was that he would leave people sliding around in his wake after the softs went off and consolidate when the field went to hard tires, that was a major miscalculation.

    Nice article, thanks.

    • Was it wise to spend time developing the Monza F-duct? They won the race, so of course it was. Anything for that vital edge.

      • You’re missing the point. They only have limited resources for development, so by working on that they’ve taken away from developments that may have helped in the remaining races (or anything in the future if the f-duct is banned)

        • I suppose you could say that because Alonso had to win this race to stay in the title fight, they had no choice but to go all out for this one race development wise, and then worry about the other circuits later.

          I recall how Dennis said McLaren spent several million alone to develop the car for brazil in 2008, showing the teams’ capacity to bear down and develop a car in a short amount of time—if the dollar figure corresponds to resources and man-hours applied. But that was the last race for that car.

  10. MinusTwo said on 20th September 2010, 17:31

    Thanks again, John. These articles are absolutely ACE. I get to impress my F1-nerd friends with new tidbits every time I read one of your technical reviews.

  11. Sutil.M said on 20th September 2010, 17:45

    Force india need to put the duct back on it was a mistake taking it off but it worked for Liuzzi so im not sure.

  12. I had no idea that the f-duct was named because the duct islocated by the F in Vodafone. Thats the most amazing thing I have learned all week!

    • US_Peter (@us_peter) said on 20th September 2010, 19:08

      I’ve heard others claim that it’s called an F-duct due to it’s overall shape through the car as well, the ducts form a sort of abstract elongated “f.” It would be interesting to know who coined that term. Earlier this year it sounded like none of the journalists using the term had any idea where it came from.

      • John Beamer said on 20th September 2010, 21:21

        Yes –it doesn’t look like one on my f s — but I guess no one really knowscas it is a media coined term but I think the vodafone f story is more plausible as it so much more obvious — IMHO!!!!!!

        • From what I remember, the name was coined in an interview by an engineer from another team due to the letter “F” reason.

  13. Another Excellent article by JB, If anyone qoutes anything dubious(Including Me :-)), I shall refer them to the JB Book of Knowledge, Hey Keith there`s a thought!

  14. mac_v2 said on 21st September 2010, 0:18

    Great article, After 30 years of following f1 this is the only place where I find new stuff.

    Thanks a million

    MAC

    • I’ve been following for forty years, and I know it all.

      A-hahahahaha!

      Ok. But I used to pal about with the
      son of the founder of Motorsport! lol

  15. Oliver said on 21st September 2010, 8:15

    I just wonder. The difference in top speed you quoted between the two Mclarens. Was it from friday practice before their final setup, or was it data picked up during qualifying?

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