2009 aero setup

[vis]

Given the projected 50% reduction in downforce for 2009 season,
are all the team running maximum downforce configuration in every race?
(That should be more or less Monza 2008 level).
If that would be the case, we will lost some interesting issues about aerodynamic setup and tweaking for every race

[timbo]

This is an interesting idea. I think that depends on how much drag will car generate, if they would generate proportionally less drag, I guess you are right, we won't see much aero varience between circuits. But there's also aero balance (that affects high speed oversteer/understeer) that may need optimization for different tracks, however, maybe adjustable front wing would do this part.

[Scotracer]

The projected downforce level was only a guide. The actual level is/will be around 80% of 2008 levels so your theory won't work.

Also the reason the cars run max downforce and some downforce is for low speed grip. Well, the slicks will more than compensate so downforce levels may be lower (relatively) to 2008.

[wesley123]

The downforce will be between 70-80% of the 2008 ones.

It is still hard to say but 50% is alot of downforce loss, that will mean that the F3 cars could be faster in turns.

The cars at the launch will be simple ones and thoughout the season the teams will interpertate the rules in their own ways so weird creations could happen.

@Scotracer; If the cars will use the downforce for low speed grip it will be useless, at slow corners the parts will generate almost no downforce so the idea is pretty much useless. The grip from slow corners come from their grip of the suspension tires etc. On tracks like monaco the cars could be a 10th slower overall as Monaco has a few medium speed turns.
The monaco setup could also be used on tracks like donington with the high speed turns requiring good grip for those turns thus needing more downforce to cope with it.

That Monaco has that high wing angles is because there sint a really long straight, if there were a few of them(so longer then exit tunnel) the cars would probably set up with less downforce as the car gets it speed from the mechanical grip.

Probably im wrong but im sure that running high wing angles for low speed corners is useless as it doesnt generate more downforce in a effective way. I think that running low angles at monaco will cause the car to be faster in the first and second sector as those only has sow corners, but in the 3d sector with faster corners it would be slower. So the pace would be the same i guess

[timbo]

Probably im wrong but im sure that running high wing angles for low speed corners is useless as it doesnt generate more downforce in a effective way. I think that running low angles at monaco will cause the car to be faster in the first and second sector as those only has sow corners, but in the 3d sector with faster corners it would be slower. So the pace would be the same i guess

High wing angles help in bracking/accelerating.

[Jersey Tom]

Lots of wing helps in braking, not sure if I believe it helps on accel. Lot of drag. Low speed where you're traction limited you're probably not getting enough DF to do much to help.

Well, the slicks will more than compensate

Says who? I think a lot of folks are putting the grip of a slick tire out of proportion. A 10-20% increase in footprint area, whatever it is, doesn't mean a 10-20% increase in grip. Not nearly.

[wesley123]

Probably im wrong but im sure that running high wing angles for low speed corners is useless as it doesnt generate more downforce in a effective way. I think that running low angles at monaco will cause the car to be faster in the first and second sector as those only has sow corners, but in the 3d sector with faster corners it would be slower. So the pace would be the same i guess

High wing angles help in bracking/accelerating.

It doesnt help in braking that much, afterall the top speeds are by far higher, they only have to brake earlier

[timbo]

It doesnt help in braking that much, afterall the top speeds are by far higher, they only have to brake earlier

But they do! You have a) more drag b) more stability. I remember someone (probably Pat Symmonds in Remault tech-file) wrote that higher wings at Monaco used mostly for bracking and acceleration, not for cornering.

[Ogami musashi]

Lots of wing helps in braking, not sure if I believe it helps on accel. Lot of drag. Low speed where you're traction limited you're probably not getting enough DF to do much to help.

Well, the slicks will more than compensate

Says who? I think a lot of folks are putting the grip of a slick tire out of proportion. A 10-20% increase in footprint area, whatever it is, doesn't mean a 10-20% increase in grip. Not nearly.

Those are not the compounds, they are softer so the footprint area increase is not the only parameter.

Estimation are around 15% increase in grip and that from Technicals so i presume they know what they talk about.


As for downforce, yes it helps even at low speed. Already at low speed in monaco trim you can have out of a 80km/h corner about 180kg of downforce added.
Knowing that the tyres this year are not with ultra high Mu, then you see it is important.

[Scotracer]

Precisely, Ogami.

Next year's compounds will be far softer than the grooved tyres of today (they will return a mu of 2.5 instead of 1.9 most likely).

At low speed you lose the U (from F(lift) =1/2*rho*A*U^2*CL) so they have to compensate by increasing CL - i.e. by increasing angle of attack. That's why they run a relatively high amount of wing at Monza compared with the aero trim on an IRL (or Indycar now) car on a speedway (not Super Speedway). Next year the cars will have more grip up until around 200km/h due to the tyres so they don't need as much wing for the Lesmos or chincanes.

[JoshJ81]

So at 200+Kph, the tire's grip becomes unusable, could you explain that alittle more please?

So with all the winglet and barge board banned, does the car actually produce alot more drag? What % would you say?

[Scotracer]

As you can see from the equation in my previous post, downforce squares with speed. So, it becomes an exponential as speed rises. Conversely tyre traction remains relatively constant with speed (actually it reduces slightly on a high downforce car).

So, at around 200km/h (this is an educated guess you must understand) the amount of grip supplied by aero overtakes tyre grip and then becomes a much larger component.



This is a graph I produced some time ago as an analysis for the Formula Student car I am designing at university. This does relate to drag but it holds a very similar comparison with lift. As you can see, at around 5m/s the drag from the projected aero becomes greater than the tyre rolling resistance. This is the same story for traction/grip as at a certain speed aero is a bigger component. At speeds in excess of say 15m/s you can see Aero is considerably larger than RR. This increases with speed.

So, if you increase tyre grip and reduce aero grip this cross-over point is at a higher speed but the ultimate grip is reduced as aero downforce is lower than 2008. So, up until this crossover point, mechanical grip means more than aero - i.e. if the crossover is higher, mechanical grip is more important.

[Jersey Tom]

Tire grip isn't unusable.. believe he's saying that over 200kph aero is dominant.

I'm also pretty skeptical Bridgestone's tires will have mu = 2.5, particularly at high load. In fact I'd say.. no way.

Also, tire rolling resistance is not constant vs speed.

[Scotracer]

Tire grip isn't unusable.. believe he's saying that over 200kph aero is dominant.

I'm also pretty skeptical Bridgestone's tires will have mu = 2.5, particularly at high load. In fact I'd say.. no way.

Also, tire rolling resistance is not constant vs speed.

I know but that was just a simple analysis - the only such one I have on this PC. It was just to show graphically the difference between mechanical and aero.

[JoshJ81]

K, I understand.

So to my second question:
So with all the winglet and barge board banned, does the car actually produce alot more drag? What % would you say?