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Canadian Grand Prix – The latest tech stories
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Canadian Grand Prix – The latest tech stories
Posted By: James Allen  |  12 Jun 2010   |  9:52 pm GMT  |  25 comments

This weekend we are back in Canada after a one year absence. The track is quite different in character from the circuits we have visited so far this season and it is an interesting indication of how the cars perform in a lower downforce configuration.

Montreal is based on a series of chicanes and long straights without a fast corner to its name. As a result the cars run the second lowest level of downforce of the season, after Monza.


To illustrate the difference in detail, take a look at this drawing of the Renault front wing from Turkey and compare it with the photograph of the wing as they have brought it here.

For Montreal they have lost the small upper winglet elements because they don’t need the extra downforce they bring and they don’t want the drag. The wing keeps the same basic philosophy, particularly with the elegant multiple channels on the endplate but it is a good illustration of the differences between a track like Istanbul and a track like Montreal.

It is noticeable, talking to engineers from other teams, how Renault seems to be making small but confident steps at every race. In Istanbul the car was faster than the Ferrari and this seems to be a team on the move. If Mercedes back off on development in the second half of the season, as has been suggested, then Renault may well finish ahead of them in the championship. After their humiliations last year both on track and over the Singapore crash scandal, Renault is an increasingly confident team.

A real brake killer
One of the problems with reducing the downforce on the cars is that the drag effect is not available to the cars when it comes to braking. Montreal is easily the hardest circuit on the calendar on brakes in terms of big, punishing stops. Monaco can be very hard on brakes because they are in use all the time and never get a chance to cool down, which can tip them over the edge.

But for big, brutal stops you cannot beat Montreal and this year the challenge is even greater in the race because the cars are carrying 160 kilos of fuel at the start. We can expect some teams to have brake problems, it’s just a question of how severe they are. The driver spends 16% of the lap time pressing the brake pedal here, which is quite high in addition to the severity of the stops.

According to Brembo, there are seven stops here of which the hardest is the final chicane, where the cars brake from 320km/h to 140km/h in just over 100 metres, which is a deceleration of almost 5g. But this isn’t the one that really kills the brakes, because they have had a chance to cool down on the long straight. It’s the stop at the hairpin which kills them.

For the hairpin the cars go from 290km/h to 60km/h but because the drivers have used the brakes twice relatively soon before, the brakes are already very hot when they are applied for the hairpin. Most of the teams have larger brake ducts here this weekend to help with this problem.


Red Bull F Duct The next talking point from a technical point of view is ironically, something which isn’t here this weekend; the Red Bull F Duct rear wing. The team tested it in practice in Istanbul, but did not use it for qualifying and the race. However our technical artist Paolo Filisetti, obtained some insights into what goes on beneath the skin, which you can see in this drawing.

The main channel is the top one and this puts the air flow out through the channel in the rear of the wing. The lower one has an exit (inset in the drawing) below the rear wing, which puts the air out underneath the wing. This helps to increase the stall, in other words to increase the effect by which the wing sheds drag. It is controlled by a fluidic switch, which is essentially a switch triggered by airflow.

However after trialling it in Turkey, they decided not to bring it to Montreal, where it would have been of great value with the long straights. The team wasn’t satisfied with the way it worked in Turkey, as it drained downforce away. This is something most teams are finding as they try to copy McLaren’s breakthrough.

The specific reason why they have chosen not to even bring it here is that the rear wings are not very high downforce in the first place. Also its likely that they have been focussed on getting it to work on the kind of wing they use for 70% of the races, rather than waste resources on getting it to work on a Canada wing.


McLaren have gone to that effort and they have made a new Canada specification rear wing specifically to work with the F Duct.

There are some suggestions among engineers that taking this line of thinking to its conclusion, we might not see anyone using the F Duct in Monza. Although this sounds counter intuitive with straight line speed the order of the day, in fact the downforce levels are so minimal in the first place there is less need to shed drag.

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25 Comments
  1. Chris G says:

    Surely if you can shed downforce on the Monza straights with an F Duct, you can run a higher downforce wing in the first place, so helping in the corners? Theyd obviously need a reasonably low downforce wing anyway, but as with Montreal where Mclaren seem to be running a deeper gauge rear wing than virtually anyone yet still top the time traps, the same advantage could be gained in Monza Id have thought?

    Also Im not certain the lower duct on the Red Bull setup helps the stall as sucj, from my understanding the fluidic switch directs the airflow one of two directions, in “default” downforce producing mode the air flows out the lower duct, when the driver activates the F Duct the fluidic switch changes the air direction so it goes along the top duct and into the rear wing.

    1. Freespeech says:

      Correct, it’s never just about the top speed whatever circuit F1 race on.

  2. jonrob says:

    Wow that endplate is certainly getting complicated on the Renault but it seems to be working.

  3. Steve Rogers says:

    Wonderful stuff again! Lapping it up as usual :-)

  4. Jon says:

    It seems like it’d be a big surprise if they don’t use it for Monza. You would think if there was one track you would need it for, it’s Monza.

    You would think that if it is something that gives you 10km/h on the straights (which I doubt personally) that Monza of all places would be the place to have it.

    You can see the other side of the arguement. Depends on resoruces I guess. We can wait and see, but for a team like Redbull, where already they could be handicapped by Renault power, you would think they would be trying to get it working. Unless they just write off the weekend and call it a damage limitation weekend.

    All these choices behind the scenes… very interesting.

    Maybe Ferrari lost out in the last few months, focussing too much on the F Duct, and not enough development of the car itself.

  5. russ parkin says:

    never mind this tech jimmer! whats in the giant golf ball at the circuit?

    1. James Allen says:

      A biosphere, left over from the Expo

      1. russ parkin says:

        cheers dear, looking forward to this race i assume? could be one of the best yet! wine in hand pie and chips on the way. brilliant

  6. phil says:

    Are Ferrari not using their F-duct this weekend? I haven’t heard any mention of it.

  7. RickeeBoy says:

    Have to say it yet again – Thanks James – these Tech bits are what really enhance F1 – Actually with all these weird and wonderful developments of double diffusers and F-Ducts its nearly getting as good as when Jim Hall was bringing out new designs of his Can-Am Chapparal’s, and that was a wonderful time. ( but that’s for the old Boy’s ) Thanks James. Love your site.

  8. Paul Kirk says:

    Thanks, James, for the tech stuf, very interesting!
    PK.

  9. michael grievson says:

    I love these reports. I’ve always wondered why they’ve never been included in the coverage. All you hear is “X team have a new wing here this weekend” and that’s it.

    Is it really a good idea to give up ok this years car? With testing banned surely it’s a better idea to keep deveolping this years car because next years cars are just an evolution?

    1. TheGreatCornholio says:

      I thought they were banning diffusers for 2011 which i’d imagine would require a large amount of work from the teams to claw back some of the lost downforce? If i’m wrong (wouldn’t be the first time) i’d appreciate being corrected on this!:)

      1. malcolm.strachan says:

        They’re banning the double-diffuser; this will reduce downforce significantly, but they will still have a single diffuser that will provide the bulk of the car’s downforce.

  10. Diamond says:

    Russ.Love your cheeky comment about the tech jibber! It can be mind boggling (but fun I think).

    The golf ball is actually a geodesic dome championed by the architect Richard Buckminster “Bucky” Fuller, who also was a futurist and inventor. (Since we are talking F1 – He even designed an automobile, except it looked more like a caravan!). So to take it off the tech stuff and point to the dome, was just putting yourself into a whole heap more tech!

    Life is not with out it’s irony. Cheers! ;)

  11. Gil Dogon says:

    Yeah, I love the tech stuff too. I have a question though about the so called “fluidic switch”. A quick google search, did not turn out any meaningful results. Can somebody explain a bit more about this device/technical lingo ?

    1. Terry Shepherd says:

      Gill, I would imagine that this ‘fluidic switch’ is something which works aerodynamically, by choking the flow into one of the ducts through the rising air speed on the straights so that the flow is directed into the other duct.

    2. Jonathan says:

      Gil – I cannot find the link at the moment but I did see an excellent explanation of it – I will post it if I can find it.

      It annoys me intensely that so many claim the rear wing is stalled – this is utter rubbish! The reality is the exact opposite. It is like an aeroplane propeller being feathered so that it simply spins and produces no thrust – and, therefore, needs less power to turn it. Stalling a wing would be like the prop being turned so that the blades push as much air about as possible – consuming vast amounts of energy but producing no thrust. In other words like an air brake.

      For the layman the best way to describe the fluidic switch is to watch water coming from a tap. Placing a finger at the side of a steady flow will pull the water to the side the finger is on. Holding a knife at a slight angle to the normal flow will see a side force applied to the knife. By pulling the flow to one side the water can now be in line with the knife and the side force will disappear – and needs less effort to hold it in place.

      Rather than slowing the airflow on one side the F duct is simply adding air to accelerate the lower side of the airflow so that it lines up with the wing and thus reduces the downforce.

      The whole idea is not so much about reducing downforce as about lowering the drag needed to create it. In a straight line there is much less load on the tyres and so they can cope with less downforce created grip.

      1. Pierce89 says:

        Actually the f-duct does “stall” the rear wing. By introducing a flow perpendicular to main flow it detaches the air from the backside of the wing.(creating a “stalled” condition)Accelerating flow on the backside as you suggested, would decrease pressure on that side INCREASING the downforce.

      2. Pierce89 says:

        oh and the fluidic switch just changes which channel air exits from.(Wing or cockpit)

      3. Jonathan says:

        As mentioned I was explaining the principle in terms a layman can understand – it is way more complicated than either of us could adequately explain here.

        You do not appear to understand the fluidic switch at all. Your second comment about the fluidic switch changing the air exit is wrong. A fluidic switch changes air flow by adding a small amount of fluid such that a larger flow changes direction. The F duct everyone refers to is where this small amount of air comes from. Until the effect of the fluidic switch is wanted this small amount of air is used to cool the driver and exits around the cockpit. By use of a knee (or in the case of ferrari the back of a hand) the driver to close off the flow into the cockpit the air is forced to take a circuitous route through the car and out to the rear wing where the fluidic switch effect is created.

        A fluidic switch can also be likened to a transistor – where a small current is used to control a larger current as needed in an amplifier.

        If you wish to get complicated you need to refer to gas laws and you will find that adding air to accelerate flow will not necessarily decrease pressure – you are forgetting that gas law equations are based around a fixed mass of gas – not one where the mass is increased.

        Once again the decrease in downforce is not the desired effect but the inevitable consequence of reducing drag. It is the reduction in drag that allows the car to go faster – as this means a loss in downforce it can only be used when this is a lesser penalty.

        Going back to my analogy of water coming from a tap the F duct is actually a bit like holding your finger in the flow and only removing it when wishing to lose drag – and this is probably why so many teams are struggling to make it work. They are adding drag to allow a fluidic switch to work but have either not made them work or not yet made the short term gain outweigh the longer term pain as McLaren have.

      4. malcolm.strachan says:

        Jonathon, just a message to trigger your email notification to let you know I replied to your comments along with Gil’s comment.

    3. malcolm.strachan says:

      http://en.wikipedia.org/wiki/Fluidics

      ^^A good explanation on how Fluidics works, with a great diagram. Simply put, you use smaller air streams to control which direction the large air stream ends up going. One way, the air stream is just dumped out somewhere inconsequential; the other way, the air stream is forced through the wing to stall it and reduce drag.

      @Jonathon: Pierce does have it right. The driver controls the small stream of air, which in turn controls the larger stream of air to either be forced through the upper element (in McLaren’s case) or through another vent. The end effect is quite simple; however, it is the means of doing so that is the tricky part.

      Also, Pierce and many others have it right about the wing actually stalling. Much like spoilers added to hatchback road-cars with curvy rear windows, it trips the flow to induce separation to greatly reduce induced drag, and to a degree, form drag. Remember, pressure exerts a force normal to the surface; therefore, with the last wing element at about 70 degrees to horizontal, much of the aerodynamic effect would be pushing that specific flap rearward. Of course, the benefit of that is that the slot-gap between the flaps energizes the boundary layer, and helps suck more air under the main element, increasing overall downforce at the price of increased drag from running the flap at such a high angle of attack.

      Turbulence and flow-separation are usually bad, and they do increase drag in certain situations (namely lower angles of attack); however, in this case controlling the separation results in less drag than what is caused by a normally-functioning wing at a very high angles of attack at high speeds. A few years ago, there was the whole flexible-wing saga, where the upper element would seal off the slot-gap, causing the flow to separate at the end of the main element and thus reduce drag. That was a crude method of what McLaren has achieved now; they are controlling flow separation, not only in terms of where the flow separates, but also when, as it is not speed-related like the old flexible-flap system.

      This brings in Pierce’s other point, of adding parallel flow only increasing downforce. Pierce is speaking of a blown flap: http://en.wikipedia.org/wiki/Blown_flap …This is what bothered me when some commentators were saying “blown wings”, when referring the stall-inducing “F-Ducts”. Adding flow to a wing will reduce pressure, despite what the gas law seems to infer; remember, any engineering calculation is only as good as it’s assumptions. A blown flap achieves the same effect that has been used for many years through simply running multiple flaps. While flow is added to the underside of the wing, it is added at such a high speed that it decreases the overall pressure (the effect of the latter overcomes the former).

      The blown flap method would increase downforce, which is why, when I first saw the Red Bull design, I got all excited because I thought that would be the effect of the lower channel: to blow the whole centre of the wing and generate more downforce, but then have the option of turning it off and stalling the wing to reduce drag… it may be the intention, but I am not sure if they got it to work correctly. When they do, it will be a brilliant execution, if my assumption is correct.

  12. Peter says:

    Another thing I have noticed is that Jenson Button was using an Arai helmet instead of the Bell in qualifying.

    Was there a specific reason for that??

    1. malcolm.strachan says:

      His attempts to keep it a secret have gone Arai!

      Sorry, terrible pun. :)

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