Flexible floor II

[Ciro Pabón]

FIA in fresh clampdown on movable floors

By Jonathan Noble Tuesday, April 24th 2007, 11:14 GMT


Motor racing's governing body has instigated a further clampdown on movable floors in Formula One, autosport.com can reveal, amid fears that some teams are still trying to exploit the regulations.

The FIA revised its testing procedures on floors after the season-opening Australian Grand Prix following a clarification request from McLaren.

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Article 3.17.4 of Formula One's technical regulations states that no bodywork, such as the floor, can deflect more than 5mm vertically when exposed to a 500 Newton load upward.

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It had been thought that the new tests had brought an end to the focus on movable floors, but sources have revealed to autosport.com that concerns remain that some teams are still trying to flex their floors.

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From the Spanish Grand Prix, the loads tests on the floors will be quadrupled from the current 500 Newtons up to 2000 Newtons - with the teams still having to remove any stay that is fitted between the bodywork and chassis.

Furthermore, the FIA will check the bodywork on the reference plane is flat and rigid with the skid block removed – with particular attention paid to those areas where the car sits on the weighing platform.

The FIA appears to be sceptical of arguments put forward by some teams that spring type devices are important for preventing damage to the floors when they hit kerbs.

FIA technical delegate Charlie Whiting has now written to all the teams to inform them of the new tests and his concerns about the situation.

In the letter, a copy of which has been seen by autosport.com, Whiting wrote: "Following detailed examination of the cars during the Malaysian and Bahrain Grands Prix it has become evident that some teams are attempting to gain an aerodynamic advantage by designing bodywork which is flexible and/or not flat.

"Explanations for this seem to centre around the need to ensure the front of the chassis or reference plane isn't badly damaged when it makes contact with the ground, however, whilst we acknowledge these arguments may have some validity, such designs quite clearly contravene Article 3.15 of the 2007 F1 Technical Regulations.

"If you want to avoid damage you must ensure your cars do not make contact with the ground as regularly as they appear to."

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It is not clear yet just how much work teams will need to undertake to pass the new tests.

It seems we can expect some changes in performance at Spain.

[Sawtooth-spike]

"If you want to avoid damage you must ensure your cars do not make contact with the ground as regularly as they appear to."

I like that bit!

Could this Be the FIA enforcing the rules?, Wow 2007 really is the year of change

[checkered]

It seems we can expect some changes in performance at Spain.

I'll say! This is serious stuff. Put 2000N under the nose of an F1 and it comes pretty close to lifting the front clear off the test platform already. That particular attention is being paid to the entire underbody with the plank removed while the force is applied to the front implies that complying to the test might force actual design changes to the entire chassis for some teams. If such modifications are to be made, wouldn't that mean that in practice these teams must also subject the changes to a new FIA crash test?

If there's a radical shakeup in the order of the teams' performance, there are going to be criticisms of what the FIA action has achieved in terms of the season beginning in very even terms as far as the top two teams are concerned. I'm certainly interested to see whether the teams will remain as nonchalant about this as they were the last time the test was changed.

The front of the chassis reference plane touching the ground in high speed, experiencing gradually increasing stress, as I understand it, isn't the main reason why there needs to be some intentional deflection of the underbody. Sudden loads as hitting a kerb are a bigger problem and the interesting question is whether a vertical 2000N is an accurate estimate to still allow some deflection of such forces or are we going to see even small driver mistakes result in drastic aero damage, shards of carbon fiber flying? On tracks where the kerbs are high, drivers could actually be forced to take very conservative lines, certainly further diminishing "straight fight" overtaking opportunities in favor of dull opportunism from other's mistakes and misfortunes.

On the face of it, some shuffling in the order of things may result in some surprising races. But as was the case with the TMD, that the FIA doesn't force changes in such basic things as chassis design and construction only during the off-season kinda diminishes the logic of the championships. These things have gone through some scrutiny before the season started, after all.

[Ian P.]

If the drivers have to stick to the actual track surface rather than bashing over curbs I expect this will be beneficial for overtaking rather than the contrary. Time will tell.
Interesting connection...could the profusion of Ferrari shark-gills or slots in the sidepods above the radiators have been a method of reducing the airflow through the diffuser. Why..?? If the moveable floor had the effect of restricting the flow of air through the sidepods at high speed, it would limit downforce. If the correction of the moveable floor (rigid rather than sprung strut) resulted in too much airflow through the diffuser, this would cause too much high speed downforce and unbalance the car. The slots in the bodywork on the top of the sidepods may have been a way to compensate.
Will be interesting to see if the diffusers and sidepods get re-jigged for the next GP.

[checkered]

Would I be

too cynical to suggest that this test could result in a significant relative improvement in the performance of the Japanese teams? There must be some worry in the F1 circles by now that they're reconsidering their position as constructors. Then again it might be that the Japanese mentality and instinct is to be less "interpretative" of the rules, so they won't even consider flexi-anything even if it complies with the letter of the rules, if not the intent? Well, I'm just thinking aloud here, we all remember the fuel capacity debacle (and subsequent punishment) of BAR Honda.

I'm still wondering about the stalling of the underbody allowing for/forcing more wing for the wiggly parts of the tracks. If the FIA believes that it takes, say, somewhere in the magnitude of 150N along the upward vertical force vector to produce the effect, there must be a drag penalty to get there in the first place. I think the argument about the diffuser being drag-economical in producing DF doesn't apply here, since to produce the force, more, not less air needs to be directed towards the underbody. And if more air is forced there in the first place, who says stall needs to be produced to achieve the intended effect in the first place?

Similarly, such lift (there must be significant lift before there's enough deflection to produce stall) has to be counteracted or it could produce terrible understeer or lack of overall grip through fast corners. That'd warrant even more wing and still more drag before the construction does what it's meant to do. It is a precarious balance at best. To me, it hardly seems worth inducing almost equal opposing forces at the cost of added drag only to gain something tangible at over (around) 160 MPH.

So I think I'm kinda asking something here. I just haven't quite gotten to pinning the actual question down yet. But I think Ian P. might have a point in stating that forcing the drivers to be more careful might actually increase overtaking. We'll see.

[Rob W]

"If you want to avoid damage you must ensure your cars do not make contact with the ground as regularly as they appear to."

I like that bit!

Could this Be the FIA enforcing the rules?, Wow 2007 really is the year of change

I love that bit...

Ron must have explained his concern over this very clearly to the FIA.

Rob W

[mrmr]

Steve Matchett has a long article on this over at Speed, short quote:

Protecting the chassis was certainly one reason for the reluctance by all the teams to install a solid support between the floor and the keel of their cars but (this being F1) there was also a significant performance advantage to be had by using a compliant support too. Actually, the word significant hardly does it justice, the advantage was massive.

When testing at Silverstone in 1993, we found that if we ran a solid support twixt the keel and the floor, the chassis received a considerable battering even without excessive curbing. However, if we raised the ride-height of the car sufficiently to avoid wrecking the chassis (an increase of no more than 5.0mm) we found that, due to the loss of aero efficiency on the underside of the car, our lap times increased by something approaching 0.7s. Disaster!

Full article at http://www.speedtv.com/articles/auto/fo ... 37/?page=1

[kilcoo316]

Yeap - so the whole thing is actually just a means to lower ride heights without battering the floor.


Pretty much what I thought all along.



Gawd, there wasn't half some gibberish around with 'stalling the diffuser' theories etc.

[checkered]

Read through the

whole of Matchett's article (watched the video feature earlier). In essence, he's answered what I was trying to ask.

I’ve heard it said that the forward floor of the F2007 had been designed in such a way that it dipped downward as the car powered along the straight, stalling the diffuser, killing downforce and so upping straight-line speed. But when I asked a high-ranking aerodynamicist for advice, if he thought that seemed likely, he was strongly of the opinion that this wasn’t the case. ‘Anyone who thinks that simply doesn’t understand how these things work,’ was his actual line.

No, the overwhelming view of things is that you have to get the forward floor to move upward, you have to protect the skid-block from wearing but at the same time you want to lower the ride-height as much as you dare. That’s where the advantage is.

Good to see that aero isn't completely separated from common sense still. I was beginning to get confused as to which direction things were supposed to flex to induce the "stalling of the diffuser". Now it remains to be seen whether the teams will opt for higher ride hights or less aggressive driving lines. Perhaps McLaren have reason to believe their car is particularly suited for such a change in regulatory policy and its ramifications.

[ginsu]

i always thought the whole 'stalling the diffuser' thing was because the ride height was so low that it introduced blockage effects to the underbody which would then stall the diffuser.

[BreezyRacer]

i always thought the whole 'stalling the diffuser' thing was because the ride height was so low that it introduced blockage effects to the underbody which would then stall the diffuser.

Acrtually, Ginsu, the duiffusers are fed from the 50 mm vertical edges, not the bottom plane of the car. Also keep in mind that diffusers do not create much drag. To disrupt the diffuser you would lose DF and likely increase drag at the same time.

[ginsu]

Certainly, if you 'stalled' the diffuser you would lose downforce, but you would also lose all of it's 'induced' drag. I'm thinking the induced drag is substantial enough that there is an overall gain of aero efficiency when the diffuser is stalled.

[BreezyRacer]

Certainly, if you 'stalled' the diffuser you would lose downforce, but you would also lose all of it's 'induced' drag. I'm thinking the induced drag is substantial enough that there is an overall gain of aero efficiency when the diffuser is stalled.

To stall the diffuser you are disturbing the air, thus probably increasing the drag, IMO.

[scarbs]

The more the FIA act and the more facts come out about the flexible floor situation, it seems the aim for the teams with these solutions has been to lower front ride height (and not alter the diffusers performance as we initially beleived). Last year the bargeboards all had to be on the step plane 5cm above the floor of the car (i.e. above the plank), this along with the numerous front wing ride height changes over recent years mean the teams need to run the car lower to recoup some of the losses. The splitter (nee T tray - flexible floor etc) is the one thing stopping the car running lower, having the floor deflect upwards a little makes running lower that bit easier.
Now the FIA are making the teams subject the floor to a higher load, this is 200Kg somewhat close to the ~280kg static load the front axle sees. Any increase in the test would see the front of the car lifted off the ground by the test loading…!

[kilcoo316]

Now the FIA are making the teams subject the floor to a higher load, this is 200Kg somewhat close to the ~280kg static load the front axle sees. Any increase in the test would see the front of the car lifted off the ground by the test loading…!

Just get a few of the mechanics (or big Ross Brawn if he comes back) to sit on the nose of 'er, that'll keep it down.