Interesting BMW comment

[RH1300S]

First - I know there's a BMW F1.07 thread, but thought this deserved to be in the aero section

A comment from Willy Rampf (Technical Director BMW) - he says that the BMW F1.07 aerodynamics have been optimised to allow for the car sliding rather than out and out grip. He feels that this years Bridgestone tyres will slide more.

All very logical - I understand what he is saying and it seems sensible.

My question is: Even allowing for the above would ultimate downforce still give you less (quicker) lap time and be kinder to the tyres - or is there merit in that comment?

[zac510]

I heard at one stage last year a bit of discussion that alluded to the soft tyres of 2006 offering peak grip at very low slip angles. As the teams tried to maximise the time that the tyres spent at this angle, they were led to many aerodynamic appendages (most discussion about which are reserved for whingers) aimed at keeping the car at a low vehicle slip angle.

Without real data, which the tyre constructors would not give up, this is hard to prove, however there is much evidence for it. Incidentally the most recent data for F1 tyre slip angles I have seen is in Peter Wright's Ferrari F1 book. Feel free to PM me more data if you have it

So I guess what Rampf is alluding to is that the peak grip slip angle of the new Bridgestones will be much higher.

To answer your question with another - wouldn't that depend on the track?

Also Rampf did not mention whether they have compromised peak downforce by making changes to allow the aero package to operate over larger yaw angles.

[Tp]

Someones copied your question on another forum just to let you know
http://www.sportnetwork.net/boards/read ... 288&sid=85

Anyway, don't understand why you would compromise the aerodynamics in that way, but it does sound familar to what I've before, that teams now look at the aerodynamics of the car when it's at an angle

[G-Rock]

I think what he is saying is just a bunch of press release bs.
Slip angles don't change much over the years. If you have more grip you have to go faster to reach your limit of adhesion and if you have less grip you slow down.

[RH1300S]

Thanks - it's entirely logical that the tyres of last year would have operated under very small slip angles (something has to give when chasing performance - otherwise they may as well go back to 1950's style slip angles).

So, yes - controlling slip angles would have been much more critical last year.

So, are they saying that some laptime may come from cars being used at higher slip angles now?

Even so back to the original question - would it still not be better to effectively have the car nailed down?

Much as I like the idea of putting some window of playtime back with the drivers..........

[joseff]

Wasn't it Newey who said that the horns are to optimize (oops, optimise ) airflow to the rear wing during turning? ie. reduce downforce loss when sliding,

Funny how Rampf makes this comment... regardless of tires (euh, tyres) slipping, teams have been dealing with crosswinds for ages. It's not like something they just found yesterday.

[zac510]

G-Rock - but the tyre rule (or supplier) hasn't changed so significantly since Michelin joined.

RH- I think I have properly understood your question now, however I can only assume that from his comment, Rampf and the team have looked at the offering of grip over the range of slip angles and assessed that an overall gain in laptime would come from changing the downforce package to work over a wider range of yaw conditions. The gains probably come in transient conditions , where the tyre could get closer to it's peak grip earlier in the corner (or for longer in the exit).
All this probably not comparable to last year's tyre as we are sure that overall grip will be lower.

I don't recall Newey saying that but I'm interested to hear what he claims the use of them are.

[RH1300S]

Someones copied your question on another forum just to let you know
http://www.sportnetwork.net/boards/read ... 288&sid=85

That's just lazy - he doesn't even take out the bit about a thread elsewhere

If you are reading this mate - you're a lazy git

[zac510]

It's OK, you're getting much better replies here

[RH1300S]

It's OK, you're getting much better replies here

Better quality replies too - which is the whole point of this forum

[kilcoo316]

There is another aspect to this... well, quite a few more.


1.) You slide, you get heat in the tyre - could be very useful for qualifying, getting a hard tyre up to operating temperature quickly.

2.) You slide, you wear the tyre - not so great for race distances, but, if its a hard tyre, it might/should be ok for wear rates, providing slip angles are respectable.

3.) Having a driveable car will surely help the driver's confidence, and allow them to push the limits more in a race - if the car steps a little, you won't lose all aero grip and make a bee-line for the tyres.

4.) It would make sense that in building a car to operate over a slightly wider range of conditions, peak performance is reduced somewhat. How big is that reduction - 1% CL? 0.1% CL? - who knows, probably no-one outside the BMW aero dept.

5.) It may be easier to follow another car, as the front wing operates at larger slip angles than before, although the understeer will still be there, the driver may be able to 'live with it' better than before.

[BreezyRacer]

I think what he is saying is just a bunch of press release bs.
Slip angles don't change much over the years. If you have more grip you have to go faster to reach your limit of adhesion and if you have less grip you slow down.

I buy what he's saying. The grippier the tire, the stiffer the whole package can be, where as less grip requires a more compliant package .. not so much a soft chassis but rather a diffuser that works over a wider ride height range for instance, and turning vanes and end plates that are a bit less "edgey" so they work well at maybe 5 degrees yaw, and maybe VGs that work over a range of pitch and yaw, rahter than the perfect 10 tenths setting at optimal and then 80% everywhere else.

And yes you want optimum grip and optimum grip means that if your driver comes in and complains about suddden snap breakaway or inconsistent balance or tires not coming up to temp, you need to make some changes. Nothing is more important than those 4 tire patches and getting the most you can from them throughout a race session.

[RH1300S]

Is this code for saying that the driver will make more difference this year?

[G-Rock]

The driver makes the difference at all years, whether you have high grip or lower grip tires. Lap time comes from taking a car to the last tenth of adhesion. If you go over, whether its a grippy tire or not, you'll lose speed and longevity of the tires.
There is nothing that can be done aerodynamically, to increase performance at higher slip angles because you'll comprimise performance on the straights, and during braking/acceleration in the form of lost downforce or increased drag.
You can see it in a race that the slowest cars are always the ones sliding around. You rarely see that in Schumacher or Alonso (except his crazy understeer setups I guess which doesn't affect the aero)

[kilcoo316]

Lap time comes from taking a car to the last tenth of adhesion.

If you go over, whether its a grippy tire or not, you'll lose speed and longevity of the tires. There is nothing that can be done aerodynamically, to increase performance at higher slip angles because you'll comprimise performance on the straights, and during braking/acceleration in the form of lost downforce or increased drag.

On the first part; the highest point of adhesion (or when the tyre is generating the most grip) is in a slip angle.

BMW expects the slip angle of this years cars to be notably larger than last years, so is designing its aerodynamics to suit. They are designing the aerodynamics around the tyre, rather than getting the minimum L/D (or -CL) figures and going with that.