Red Bull RB9 Renault

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aral
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Re: Red Bull RB9 Renault

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Webber was trying to stay ahead of Alonso after his brush with V d G. Could it be that he was using KERS and that the extra power supplied by that is capable of being pulsed? Nobody else appears to have had so much accelleration from the corner, witnessed by the lack of any other tyre tracks.

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WillerZ
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Re: Red Bull RB9 Renault

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gilgen wrote:Webber was trying to stay ahead of Alonso after his brush with V d G. Could it be that he was using KERS and that the extra power supplied by that is capable of being pulsed? Nobody else appears to have had so much accelleration from the corner, witnessed by the lack of any other tyre tracks.
Per the regs, KERS has to enter the drivetrain before the gearbox (and therefore before the differential). So whether or not KERS can be pulsed it wouldn't explain the left/right alternation we see in the image above.

Whether you could legally pulse KERS, and whether it would help, are interesting questions; but perhaps something for another thread…

bhall
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Re: Red Bull RB9 Renault

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gilgen wrote:[...]
Could it be that he was using KERS and that the extra power supplied by that is capable of being pulsed? Nobody else appears to have had so much accelleration from the corner, witnessed by the lack of any other tyre tracks.
I don't think so.

5.2.4 The amount of stored energy in any KERS may not be increased whilst the car is stationary during a race pit stop.

Release of power from any such system must remain under the complete control of the driver at all times the car is on the track.

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WillerZ
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Re: Red Bull RB9 Renault

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bhallg2k wrote:
gilgen wrote:[...]
Could it be that he was using KERS and that the extra power supplied by that is capable of being pulsed? Nobody else appears to have had so much accelleration from the corner, witnessed by the lack of any other tyre tracks.
I don't think so.

5.2.4 The amount of stored energy in any KERS may not be increased whilst the car is stationary during a race pit stop.

Release of power from any such system must remain under the complete control of the driver at all times the car is on the track.
So label the button "Pulse KERS". Job done.

bhall
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Re: Red Bull RB9 Renault

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WillerZ wrote:So label the button "Pulse KERS". Job done.
I think that would fall afoul of the "complete control" aspect of the regulation, because the KERS control unit would have control over how KERS power is applied.

At any rate, I think the stuttered tire tracks are the result of a stiff suspension setup. We know that the RB9 has excellent aerodynamics, and we know that good aero requires a stiff, stable platform. We also know that stiff settings aren't exactly kind to tires, a problem with which the team has struggled all season. And finally, the RB9 was consistently slower than both Ferrari and Mercedes through S1 and S3, both of which feature corners where low-speed traction is paramount. Conversely, Vettel led the way through S2 where the importance of low-speed traction is greatly diminished.

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WillerZ
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Re: Red Bull RB9 Renault

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bhallg2k wrote:
WillerZ wrote:So label the button "Pulse KERS". Job done.
I think that would fall afoul of the "complete control" aspect of the regulation, because the KERS control unit would have control over how KERS power is applied.
I agree with you, if it is pulsing in reaction to traction. However if it's just pulsing in a pre-determined pattern with no reactivity I think it would be OK. They are already allowed to have a dial/parameter for KERS discharge amount, why not another one to dial the strobe pattern from a set of patterns? Basically like variable-intermittent wipers on a road car.

I do not think this is what anyone is doing, but I do wonder if it would be better, worse, or the same as the more-normal on/off nature of KERS discharge.
At any rate, I think the stuttered tire tracks are the result of a stiff suspension setup. …
So the alternating dash-pattern tire marks are from a stiff car oscillating left/right and the gaps in each track are where that wheel has either enough weight over it for good traction, or so little that it's entirely off the ground. Makes sense.

I'll be at Silverstone for Friday practice; I am wondering if there is any evidence I could collect to settle the debate of what's really going on (presuming it continues to go on). Any suggestions on what to look for and at which corner to look for it are welcome.

bhall
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Re: Red Bull RB9 Renault

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WillerZ wrote:So the alternating dash-pattern tire marks are from a stiff car oscillating left/right and the gaps in each track are where that wheel has either enough weight over it for good traction, or so little that it's entirely off the ground. Makes sense.

[...]
Pretty much. We can even see the effects of weight transfer on the car through the turn, because the left, or outside, tire track is solid longer due to the left side carrying most of the cornering load. The inverse is true for the right, or inside, tire track.

spiritone
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Re: Red Bull RB9 Renault

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With the technology involved in the shocks that these car have i doubt that the car would go that far oscillating back and forth. There is something else going on here.

PhillipM
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Re: Red Bull RB9 Renault

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WillerZ wrote: Whether you could legally pulse KERS, and whether it would help...
It's something that's been used before through other means, both in F1 and more recently in MotoGP and similar, as a way of finding more traction.

CBeck113
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Re: Red Bull RB9 Renault

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Basically a negative ABS system :idea: interesting, but still shouldn't cause these alternating marking

But I'm also not sold on the oscillation theory, since I can't believe that an F1 car will oscillate that much. If this were the case then they wouldn't have a stable car out of slow corners. Unless the tires are solely responsible for this, but then we'd see this from other cars too.

Nope, not convinced yet :|
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scuderiafan
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Re: Red Bull RB9 Renault

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cobart wrote:
SatchelCharge wrote:Are we looking at the "TC-esque" rubber trail, then? Looks more like the result of the bumpy track to me.
Maybe it is smart differtial ? look at the trails ...left right left right alternately
I see what you're saying, but I think it has to do with the angle of the track surface, where the camera was, and the angle of the car exiting the corner.
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Patiently waiting...

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scuderiafan
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Re: Red Bull RB9 Renault

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CBeck113 wrote:Basically a negative ABS system :idea: interesting, but still shouldn't cause these alternating marking

But I'm also not sold on the oscillation theory, since I can't believe that an F1 car will oscillate that much. If this were the case then they wouldn't have a stable car out of slow corners. Unless the tires are solely responsible for this, but then we'd see this from other cars too.

Nope, not convinced yet :|
Negative ABS = TC
"You're so angry that you throw your gloves down, and the worst part is; you have to pick them up again." - Steve Matchett

Patiently waiting...

bhall
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Re: Red Bull RB9 Renault

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CBeck113 wrote:[...]

But I'm also not sold on the oscillation theory, since I can't believe that an F1 car will oscillate that much. If this were the case then they wouldn't have a stable car out of slow corners. Unless the tires are solely responsible for this, but then we'd see this from other cars too.

Nope, not convinced yet :|
Actually, I don't think the car was especially impressive through slow corners in Canada. It was consistently slower than both the Ferrari and the Mercedes in S1 and S3, both of which feature hairpin turns that favor good mechanical grip.

In any case, check out this video for some great slow motion footage of tire oscillation. The best example can be seen at about 0:55.

[youtube]http://www.youtube.com/watch?v=WCRBYHWZyLM[/youtube]

Here's some more slow motion footage of last year's McLaren porpoising due to suspension resonance.

[youtube]http://www.youtube.com/watch?v=PGIMYnyqbyw[/youtube]

And here's a little interactive thing about resonance and damping.

For whatever reason, be it an abrupt braking event to avoid hitting the Caterham followed by "hard" acceleration, or simply hitting the curb "just right," I think something briefly caused resonance in the rear suspension or in the tires, which then caused the car to oscillate. That oscillation didn't last for very long until it was arrested by dampers, as evidenced by the relatively short tracks left behind, and it probably only happened once, as evidenced by a lack of similar tracks.

Image

Basically, I think it was just a freak occurrence that ordinarily wouldn't happen, because the car's dampers are tuned to control such oscillations as much as possible. But, as well all know, nothing is foolproof, and a super-stiff, aerodynamically-stable suspension has little capacity to handle "unforeseen," for lack of a better word, phenomena.

(Incidentally, I don't think the tracks are indicative of osculation from side to side; I think it just looks that way because they're curved.)

Greg Locock
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Re: Red Bull RB9 Renault

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flynfrog wrote:wheel hop

You see it in drag racing all the time. Well pretty much any car can do it.
I've seen very similar tracks from powerful (400 hp) RWD cars in damp conditions. The root cause is torsional oscillations in the driveline, caused initially by one wheel breaking traction. In production cars the engine mounts are often part of the problem. If sustained it can easily break driveline components. Typically the frequency is 6 Hz in production cars, I expect the driveline in an F1 car is stiffer so the frequency would be higher. It is a bugger of a thing to model.

Robbobnob
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Re: Red Bull RB9 Renault

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Was this the collision between Webber and VDG?

Because if so, the loss of the end plates on Webbers car would have had an effect of the aero. The Red Bull wing (as well as Ferrari and other teams) are forever trying to increase the consistency of the downforce generated.

It is possible that the loss of the endplate caused the airflow to separate or generate flutter and cause porpoising in Webbers car. Due to it being isolated to one side of the FW this would cause a torque reaction about the front suspension.

I havnt heard anything about Red Bull having a front / rear interlinked suspension but giving that Mercedes have had one in development for so long and Renault also experimenting with such a device it would be foolish to assume that Red Bull havnt experimented with and/or already have a interlinked suspension which either controls pitch variations and roll variations. (being so aggressive on their rake setup I have always had my suspicions).

A torque reaction at the front of the car would definitely transfer through an interlinked system and even conceivably be magnified by such a system. This transfers through the rear suspension and is enough to create a left/right oscillation....
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