Mercedes GP MGP W01

[mep]

The inerter/pullrod agument is quite good at least for next year.
This year they don't get a disadvantage by this because only RedBull is using it and they are not the only ones driving in front of Mercedes.

Regarding high nose, I would be very surpised when we will see low noses next year.

[marcush.]

The inerter/pullrod agument is quite good at least for next year.
This year they don't get a disadvantage by this because only RedBull is using it and they are not the only ones driving in front of Mercedes.

Regarding high nose, I would be very surpised when we will see low noses next year.

me too.but the pullrod layout as used by RB at the back could almost be fitted in to fit on top of the splitter area that would move a considerable amount of weight from the front top...would make for easier flexing of the splitter as well under load too..
quite a wild one i know...

[747heavy]

just a quick comparsion of the times of Sutil vs. the MGP in Spa.
the gradient of the line shows how much a car is losing (line falls) or gains (line raises) in comparsion to the leader / other car.
Sutil was faster for most of the race, and the two MGP`s where quite even matched in terms of speed/lap time for most of the race.



I may post the full analysis in the Stat/Data thread later on.

[pipex]

I have for years heard the argument of the stiffness problem of the chassis (since the Honda days, 2007 to be exact). I'm not too sure that it is the problem this year. It is very strange because they have one of the specialists in that area, Dr. Gary Savage. I really don't know but maybe it has something to do with another kind of stiffness. For example from this nice paper
http://www.gef.es/Congresos/24/PDF/3-13.pdf

Suspension kinematics & compliance requirements are dictated by the team’s vehicle dynamics engineering group and the tyre supplier. The suspension geometry must take into account a number of factors including; anti-squat, anti-lift, roll centre, camber change with bump and stiffness (especially toe and camber).

What is that kind of stiffness referred to in the quote?

[mep]

i would like to give youthe following link.


http://www.scribd.com/doc/28015575/Form ... ngineering

from Gary Savage ,who works at Mercedes lots of Brawn BGP001 chassis construction pics and insight in available technology.

Nice reading but this side sucks terrible.
Does anybody has a pdf version of it?

[747heavy]

Suspension kinematics & compliance requirements are dictated by the team’s vehicle dynamics engineering group and the tyre supplier. The suspension geometry must take into account a number of factors including; anti-squat, anti-lift, roll centre, camber change with bump and stiffness (especially toe and camber).

What is that kind of stiffness referred to in the quote?

installation stiffness of the suspension, also called elasto-kinematics.
In simple terms, when your wishbones,rims,wheelsbearings and/or uprights etc. deform under load, it can/will change the camber and toe settings of your car.

This can be intentionally, like in modern road cars, or by "mistake", making the parts not stiff/strong enough.
If designed into the suspension, it can help to tune the characteristic of the car.
If done by "mistake" it can make your life very difficult. Because your car does not responed in a "normal" manner, and not as you would expect/anticipate it to do.

As you try to make everything as light as possible in F1, you have to make some compromisses. (stiffness vs. weight).
No part on a race car is infinite stiff, but if you underestimate the loads, your car/component is going to see, you may have more deflection in your parts, then you would like.

Among other things, elasto-kinematic effects can be used to generate steering at the rear axle for example, so the car can become more or less OS/US under side loads.
Some road cars use it to make the rear wheels toe-in more during braking, to increase stability.

[pipex]

Thanks for the clear answer 747heavy

[747heavy]

you normally test for this, to make sure your design and calculations are correct.

Here some photos of such tests, it´s not an F1 car, but the procedures are similar.





Toyota F1 chassis test facility.

[JohnsonsEvilTwin]

747

So if this is the case with the W01, would it not be possible to replace these parts with lighter and stronger materials?

I'm of the opinion that Mercedes/brawn were doomed the moment the tyre miscalculation was made, as this had a knock on effect for the rest of the car. Scarbs made mention of a lighter splitter in an effort to get the weight backwards, but by then your concept becomes contrived. Especially with the Mercedes uber compact rear end...

As dissapointed as I'm with the W01, I hope that lessons can be learned.

[JohnsonsEvilTwin]

From Scarbs F1 Blog

Fundamentally the car has the wrong weight\aero bias, with it being too far to the front. Last year one of Brawns strengths was its extreme forward weight bias, typified by the large slab of ballast in the front splitter, when the wider front slicks rewarded a +49% bias towards the front. This year the tyres changed, the front tyres being 25mm narrower with a 20mm narrower tread, the rear tyres were also stiffened to cope with the heavy fuel loads. Most teams perceived the loss of grip from the rear tyre change would not offset to loss in front end grip from the narrower front tyre. Perhaps Mercedes (nee Brawn) felt the tyres would still favour a high percentage of weight towards the front, indeed the car still sports a significant slab of ballast in the front splitter.

Tyres work within a window of ideal vertical load. This load comes from weight distribution and downforce, simplistically the former affects low speed grip and the latter higher speed grip. Teams need to balance the static weight distribution and downforce front to rear to suit the tyres. A graph of load versus grip for a tyre will see significant drops either end of the scale as the tyre fails to work when either over or under loaded. It seem that Mercedes have too much load on the front tyres which will see them give up grip as the tyres gets too heavily loaded, this induces understeer.

Conversely they have too little load at the rear which will compromise traction off the line and out of slow turns, but also induce oversteer. Having both ends of the car with incorrectly loaded tyres loads, will produce a car lacking in balance. The team could reduce grip at the rear to balance the car, but will then have a car lacking in grip.

Shifting weight also demands a shift in aero balance, for Mercedes this means more rear downforce. this cannot come purely from more rear wing angle as the drag that produces will slow straight lien speeds. So ideally greater diffuser development is needed. the team have been quick to get a passive F-duct running, this will certainly aid the ability to run more rear end downforce, but they must be careful its benefit is not eaten up by the need to run more rear wing or sales they will lose the advantage it gives other teams.

So then this does explain in good detail, why Mercedes have struggled. It explains their set up woes and even how that affects their straight line speeds.
In all a brilliant piece by scarbs.

Full link here.
http://scarbsf1.wordpress.com/2010/04/2 ... edictions/

[747heavy]

it depends which parts causing the problem.
If your whishbone or upright is not stiff enough, and it flexes, you go and design/make a new one, which is probably a bit heavier, but still better, then having uncontrollable flex.

If you find out that your chassis/monocoque/tub is not stiff enough, and that it is flexing, or the pick-up point where your wishone connects to the chassis, there is not much you can do, when your chassis is homologated -IMO

If they have a chassis flex problem, then they are really screwd, this is as bad as it get´s.
It´s much worse then a wrong weight distribution.
You remeber that I said that earlier, when we where talking about the weight distribution/tire problem.

A weight distribution problem, harms you - yes, but it does not puzzle you.
If you work in production based touring car racing, you will have a "wrong" weight distribution most of the time.
Still, people in a FWD car will beat a BMW with a "better" weight distribution. On some tracks is more a problem then on others, but it´s not fatal.
A chassis stiffness issue is fatal, and there is no work around for it, apart from making a stiffer chassis.
It would go a fair way to explain why they are better in race trim, but don´t get the "new tire" gain, in qualifying.
Something like this is typical for a stiffness issue. You are o.k. on used tires, but you can´t get the gain from the extra grip of a new tire, because all what you do is "wind up" your chassis.

The other problem, is that chassis flex is like a spring, but without a damper.
If you get it excited, it will oscillate, playing havoc with your corner weights/tire loads, for a while.
It´s a 1a f.... u. , difficult to recover from it, as it will remain the weakest link in your chain, no matter what you do with your set-up (springs and dampers).

[747heavy]

still unless they mold xx kg ballast into their tub, the weight distribution is recoverable - IMO, unless the car is overweight to start with.

and there is not logical explaination, as why they where gambling on this weight distribution.

just found this in a interview with the head honcho of Bridgestone`s racing division:

Q: How much more narrow is the new front and did the teams have to do anything in particular to accommodate it?
TK: It is actually 20mm more narrow (including wheel width) than the 2009 specification (2010 front tyre size: 245/55 R13) and it enables the cars to be better balanced from front to rear. From the teams' perspectives, they should have taken these new fronts into consideration when designing their 2010 cars and they were asked in particular to consider designing the cars with more rear carrying load in order to get the best out of the tyres.

Unless they just did a cut and shut job with the BGP 01 to fit a larger fuel tank, there is no reason why they would ignore Bridgestones advice, and think they are smarter then smart.
Sorry, but something does not sound very plausible to me.

[JohnsonsEvilTwin]

Yes I remember the post of the tyre/weight distribution. I also see your point on the oscillation of the chassis if its flexing, and the influence it would have on the tyres...

What puzzles me, is that Mercedes/Brawn should have seen this being an issue. And a question to all, when does the design of the car become "officially" homologated?
If caught in time Mercedes may have been able to make modifications.

[strad]

I've wondered...Maybe you hot shots will know..
Years ago..80s if memory serves they went thru a period of playing with the tire shape by running wider or narrower rims.
By doing so could they not alter the handling characteristics of each end..I'm sure I'm probably not wording this right and besides the FIA probably mandate rim width along with every other thing.

[747heavy]

Yeap Strad,

you are absolutely right about this.
It is/was also used in other race series.
I know, that it was used in the early 90`s on Gr.A rally cars, but not
too extrem. +/- 0,5" at the time in WRC

I think you will find an episod about it and some good details in the book "The Unfair Advantage" by Mark Donohue with Paul Van Valkenburgh.
It dates back to the 60´s,and Jim Hall also experimented with that.
Depending on what you want to do and your base tire, it can help to put more "rubber to work" in the corners, gaining an advantage when tire width is limited by the rules.
But with todays racing tires, it´s difficult to go to the extremes.

It´s done moderately to alter/change the cornering and/or vertical stiffness of the tire. With this you can fine tune the handling characteristic/balance of your car a little bit.

I think there is still some freedom in the rim width rules of F1 by the FIA. Marcus started a thread about it, and what people could do with it.

Unfortunately it does not help to solve a chassis stiffness issue, but it is another tool one could put to work.

Some of the tuning folks still do it to the extremes, if you google for "tyre stretch" in the picture search, you will find some extreme examples.