ColorChange

Ken: Can't determine time base from the g-g plot. I do have other data that shows speed (along with lat and long g's) which would get us closer. If you are asking the question in trying to determine how deep he is trail braking, I can't show that exactly as I just got this data 30 minutes before my post. I will continue to look at it to try to answer Sunday’s question of "heavy trail braking" which I think he is doing. Here is why.

Follow the right line I highlighted on the plot. You will see that he transitions from full braking, to full max lat g’s, to accelerating (look like he made a small mistake at 0.4 +long g’s), and then continues to blend in full accel at track out. I just can’t tell you where the max lat g’s occurred but I am confident it is somewhere in the vicinity of the apex and no where near the turn in point.

Mike in Chi

Colorchange

Where did get that chart?

TIA

SundayDriver

ColorChange

Mike:

I got it from a relatively new book, Ferrari Formula 1 2000, Under the skin or something like that.

Mike in Chi

Colorchange

Thanks

Dan Metz used the exact same chart in his Chicago region presentation last month. He had a copyright on it, but that may have been for the presentation, not the source of the chart.

Metz also took the G-G diagram into three dimensions to a volume - i.e. G-G-V, using Aero grip as the third axis.

But that could bring the Racing board to a standstill.

Geo

That would be fate.

I wonder if this thread will last a year?

chris walrod

One must keep in mind, (if this is a G-plot from Shumi's data aquisition) this is from a ground-affect vehicle where pitch and roll control is paramount to prevent the tunnels from 'burping' and maintaining pitch sensitivity. As we know, its not how much downforce one has, but how the center of pressure is controlled and maintained near CG.

Left foot braking plays a slightly different role in ground affect cars..

Carrera51

Color Change can't be Ghetto in disguise. His grammar is too good.

mitch236

Of course, if you do buy it you probably won't be able to afford to be at the track any more!

mitch236

I would like to know one thing, how do you know what his car's fc is?

SundayDriver

If you are asking what I think, there is a two part answer. First, the bold colored 'circles' are the fc at different speeds. Second, you can't really draw a fc in the classic sense because the grip is very depencent on speed (aero). That, of course, makes this a terrible example to use (but all g-g diagrams are pretty much worthless by themselves). If the light line (actualy data) is on, inside or outside of a fc line, what does that mean? The answer is that it means nothing without knowing a bunch of other info. What is the speed, so where is the theoretical fc. What is the attitude of the car, therefore what is the REAL fc at that point.

Evidence of trail braking? Not really. You don't know what the track is doing. So CC finds one line (bottom right) that he thinks is trail braking. Well, it is, in one sense. But if you trace it backwards (which is hard to do and be sure what line is what) it appears the car transitions from one direction of turn to the other very quickly. In other words, there is no straight in which to brake. So if all you have is turns and no straight, then what significance is the fact that he trail braked there - he had no freakin choice.

Of course we know that fast drivers trail brake but not in the way that CC insists they do - heavy (ABS level or threshold) to the apex.

ColorChange

Mitch, assuming your past the EXACT issue you’ve raised before, his fc changes quite dramatically because he is driving such a high down force car. The graph shows multiple graph overlays of the fc as a function of speed. It is really interesting. Because we do not know his speed from the g-g diagram, we can only guess what it is from this graph. Having all the data would tell us his speed and give us hard data.

Now, for a simple real life answer ... He's fricking Schumi! Trust me, he's on the fc almost all the time.

ColorChange

Mark:

Here is a direct challenge to you and I’m rightfully ticked off. Here is what you said Of course we know that fast drivers trail brake but not in the way that CC insists they do - heavy (ABS level or threshold) to the apex.

Do not misrepresent my positions. I have never said to always trail brake to the apex. The amount of trail braking is dependent upon the car and the turn (and the skill of the driver). The only time I said anything remotely close to this was regarding a THEORETICAL argument for a car with a perfect ABS system, and I won’t go into that now to minimize confusion. You owe me an apology/retraction for a severe misquote.

Gee Mark, here is one of your really witty Haiku’s:

tb is fastest
the undisputable truth
if I ignore facts

This sure doesn’t sound like support of trail braking to me.


Gee, let’s look at some more of your wittiness:

Master Engineer
Every corner he trail brakes
Why is he so slow

Gee, further support for trail braking Mark?


And now to further your destruction, I made the following post that you never disputed:

Sunday, Mike, Mark, Ed, John, and Jim OK guys, consider yourselves warned, but tell me what text you would accepts as direct proof you are wrong. I might suggest the industry standard and highest respected text ever written, Milliken "Race Car Engineering", but if you have something more authoritative, please suggest it. And John, for the record, we will not be using your incorrect definition of trail braking, we will use the industry standard which is “braking during and/or after turn in”. Finally, I will restate your position so there is no confusion (or backing out later), “It is usually not fastest to trail brake.”. Please correct this statement if I am stating your position wrongly. Good luck gentlemen as you lay your heads upon the chopping block.

And don’t try to say I would define trail braking when I quite accurately defined it in the paragraph above. So, you did not dispute the specific statement that trail braking is fastest in almost all turns. I then supplied numerous sources that say trail braking is usually fastest, and here I just presented data that the best driver in the history of mankind ALWAYS trail brakes (at least at Imola) and you still lack the character to admit you are wrong. Furthermore, you misquote me (in an effort to hide your own errors in my opinion). Low character. Unless of course you admit your errors and apologize for the misquote. I doubt you will do either.

bob_dallas

Yep - I agree with you. First time I looked at this it was a little confusing with all the different lines on it but once you think it through logically the different thresholds make sense. As you say - aero downforce plays a HUGE role with these cars so the max lateral and braking Gs increase substantially as the speed increases while the max acceleration Gs decrease since they are almost exclusively based on acceleration of the car and not traction that can be enhanced with downforce.

As to being able to get something meaningful out of these charts - yeah..it's interesting but too much data overlayed to come up with many exact conclusions without some big assumptions. Of course a safe assumption is he's doing everything right and not threshold trailbraking through the apex.

One of the things I frequently hear is that Schumi's mid-corner speed is one of his (many) strengths and that he's extremely consistent in this phase. IIRC he's generally 1-2mph faster mid-corner than his closest rivals - that's a lot in F1 terms. To maximize mid-corner speed means he's making a very quick and smooth transition from brake to acceleration using both feet in an amazing manner. I highly doubt he's trailbraking to the apex much if at all...

ColorChange

Bob:

This is exactly the damage that Sunday caused with his horrible misquote. I never said to trail brake always to the apex. This would be stupid. Sometimes, maybe, certainly not mostly. The point of showing the graph is that he trail brakes quite a bit. If someone can’t see that, I don’t know what to say.