smokey

CC, do you have a law degree as well as an engineering degree? The point here is to inform and learn, not to argue for the sake of argument. The differences here seem to be of semantics and nuance: i.e. what do we mean by "very" different line, or "using" gg or fc data? As someone said, "very" can be three or four feet difference. "Using" might mean a casual reference on segment time versus max g.
Suggestion: renegotiate the deal with she-who-must-be-obeyed, and go racing. There's a very old rule in life: when the flag drops, the bs stops.
Iwillneverreadanotherccpostiwillneverreadanotherccpostiwillneverreadanot herccpostiwillneverreadanother

ColorChange

Smokey, you're right, racing would settle it all but, me no can go there, Daddy first. No law degree but sadly I spend a fair amount of time on legal issues, especially lately.

I'm not playing semantic games. I really do believe that fc driver analysis is used as I can't see any other way once you get below the level of segment times. Here is how I think it works.

1. look at g-sum plots over a lap/turns, whatever.
2. any time you see a g-sum drop, figure out why
3. why is defined by steering, brakes, throttle or clutch – what the driver did.

I just can’t see any other way to do it and if Geo can tell me, I’m curious as hell. Honestly.

C’mon Smokey, are you saying you need a 12 step CC program.

Bob Rouleau

Two years ago I raced a Formula Ford. The car was fully instrumented. In practice sessions we would review the data comparing my performance with my team mate. The system had a very nice interface. We would play back our laps on a PC and watch our two cars side by side moving around the track map. Irrespective of where the cars were in reality you could position them side by side on the moving track map. A click on the car icon would open a data box showing speed, RPM, lat and long G's steering wheel position and throttle. It was very useful to see what was happening and compare the performance of both the driver and the car. I was faster in certain places and slower in others. The result of the analysis was that both of us went faster. I remember being slower in a carousel turn and my team-mate was pulling a higher lateral G load than I was. In this case it was me being overly cautious, I should have been going faster because the data showed us that the car had more lateral grip than I was using.

My point is that the primary indicator was speed. If one car was going faster than the other, then we'd look at other data to see why. To add emphasis, the goal was speed, not being at some point on the theoretical friction circle. Where there was a differential, then we'd look at other data to see why.

Once we had learned each other's tricks, the chassis guys would look at the data (including plots like the ones CC posted) and they would pick apart our laps. For example if we were not loading the car enough (lat G's) they would show us where we could use more of the car's grip.

Lap times and plots showing steering wheel inputs and braking allowed the team manger to evaluate how consistent we were - a key point for him.

Finally segment timing of our competition was used by the chassis gurus to tweak the car set up. All in all I was very impressed and learned a lot about my own strengths and weaknesses. The team boss certainly used the data to evaluate our driving skills - who was smoother, easier on the car, who was bouncing off the rev limiter or downshifting at dangerously high revs and importantly who was more consistent.
And, my point is (ta da!) that data analysis is a vital tool used by race teams to improve the performance of the car and the driver. Was the friction circle mentioned at any time in this process? No. It was about speed -speed and speed. Were lat and long G's important? Yes.

CC observes that teams use telemetry and data analysis. That seems pretty obvious. Do they look at lat and long G's? Sure. Are we arguing over minutia here? My personal experience was that the friction circle concept was acknowledged (to the extent that Lat and Long G's were examined) but not the focus.

Rgds,

Geo

You are some kind of idiot. Your lack of data discredits my source????

You are just a flaming moron.

I've also named my source before. More evidence of a reading or learning disability. My source is Doug Gerard. He wrote much of the current software for Competition Data Systems (CDS). He worked for them for 5 years. Now he works for Roehrig Engineering doing programming for shock dynos and seven post shaker rigs (and shaker rigs are like advanced study for DA - they use data collected and then work on predictive scenarios). He knows infinitely more about this subject than you ever will. He works with or has worked with (that I know about, there are definitely more) Ferrari, Toyota F1, several Champ Car, IRL, Toyota Atlantic, Trans Am, ALMS, and NASCAR teams. He not only have visited their fatories and shops, he has gone to and goes to their test sessions as well.

But that's OK. You know more than professionals in the field dealing with professionals at the top level. You know, you should send Ferrari a resume and tell them they should get rid of that idiot Ross Brawn.

Another example of your reading/learning disability. Or that you are just a plain ol' moron.

When did I ever say or imply that teams don't use data to compare one driver to another or one session to another? Never. In fact, I've stated many times that they do this. You problem sir is you absolutely, 100% refuse to believe they do not use FC plots to do this, despite being told directly by a professional in the business and indirectly through me by a professional in the business.

Well DUH!

1. Nobody and I mean NOBODY here disputed that professional teams use data to analyze drivers. That's why they HAVE data acquisition.

2. Yes indeedie what they use is up for debate. With you. You cling to the FC and no matter what anyone says you keep clinging to it. You won't listen to Chris W who is a professional, working in the industry, nor to what my buddy, another professional iworking in the industry at the highest levels had to say.





I've already done that. I've already posted that. Go search for it. I'm not going to spoon feed you just because you either have a reading or learning disability. If you don't find it, I don't care.

BTW a little hint, it all comes down to.... tic toc tic toc

ColorChange.... You're a troll.

I'm done. Say what you want. I don't care anymore. You aren't interested in the truth or in learning. You seem to believe by the sheer imposition of your will that the world with conform to your view of it. Responding to you is a waste of time and this is the last time I waste my time on you.

ColorChange

Bob:
When you say “To add emphasis, the goal was speed, not being at some point on the theoretical friction circle.”, this is exactly what you are doing when you say the other driver was pulling higher lat g’s on the carousel. He was closer to the fc limit then you so you sped up to get closer to the fc, and therefore faster. Isn’t that the same thing?

Speed is a good indicator, segment times are better.

The best way to do this is look at g-sum, and then the individual components (lat and long g’s) to see where you are falling short. This is an fc analysis, not determining exactly where it is, but maximizing it, and this is what I have been saying. Am I missing something?

Well we are pretty close in agreement. While the fc was not specifically mentioned in your posts, you used the principles repeatedly, and correctly. The fc is max g-sum is max lat and max long g’s. You were trying to max g’s and this is my whole point so I think we agree. I disagree that speed is important on its own. Speed is not, time is (and yes, higher speeds usually allow faster times but not always as we discussed in apex speeds – where slower can be quicker).

Maybe it is a minutia in dispute. I call using g analysis as an fc concept analysis.

Geo:
Don’t see why you’re so upset. Where did you name Doug Gerard before? I looked and couldn’t find it. Thanks for the name.

I don’t know if the use g/g plots but I suspect they do. What I call fc analysis is maximizing g’s (and max g’s define the fc). The two are directly related. If you are saying a driver pulls higher g’s here and he’s faster, I call this an fc analysis. Is this a semantics problem again?

Chris W told me his work was related to car DAS analysis, not driver DAS analysis and that he wasn’t qualified to discuss what those engineers might do. You have jumped to a wrong conclusion and said they don’t use it. ChrisW doesn’t do it because that’s not his job. I hope I have spoken for Chris W accurately.

You also skipped my questions again with amusing graphics. Not a very persuasive argument.

Geo, or anyone else, please tell me where he said how teams analyze driver performance in any level of detail?

M758

Color I think are getting to the heart of the matter.

It appears through you posts that your goal on the track is to be on the edge of the friction circle. This is what most of us take issue with. For racer being on the edge of the friction circle is not the goal. It may be a way to get to the goal, but is not what they strive for.

Racers strive for winning. That means being front of the next guy at the drop of the checkered flag. In fact lap times are also a means to that end. Now the best way to try to win is to be fast. So that is a very important goal. Speed is determiner for laps times. Segment times are also a determiner of lap times. What must be remember is that high speed and low segment times do not always result in low lap times. Look at F1 qualfying. Here guys shoot for low lap times. Even so some guys are faster in different parts of the track. Rarely is pole setter fastest in all segments. Of couse this year may be the exception. Anyway racers will give up segment times in one area so that the ENTIRE LAP is faster. Now where you G-sum and friction circle come into play. Well much later on. If a driver sees that they need to optimize a particular segment so that they can minimize overall lap times, then and only then will the start to car about G-sum. Yes in many corners you do want to max g-sum, but only in such a way as to maximize speeds and min segment times so that the overall lap is faster so that you may either pass or stay infront of a competitior.

There other cases were g-sum is not even considered important.

So most of us drivers DE & Racers alike find it way off base to concern your self so much with max g-sum. We care about overall lap times and segment time long before G-sum is an issue.

This is gist of what most folks have been saying. overall lap time is the number 1 data field followed by segment times. After that every thing else is just geared torwards how to lower lap times or segment times.

ColorChange

M758
OK, I agree time is everything. My personal goal is to drive as close to the fc as consistently and safely as possible along something resembling the best line.. Now, if I am effective in doing this (fat chance, but that's my goal), I will be the fastest (lowest lap time).

What I am saying is, maximizing g's in the appropriate direction is the fastest. Always! So, if you can pick the ideal line, and then maximize g’s on that line, you are going as fast as that car (as set up) will go. What you want to do then is maximize your g’s along your line. This means you can’t make unnecessary g creation, or waste g capability.

Does that help? I’m not sure after reading what I wrote.

ryoji

Few years back a tire company's project team sat 30+ sensors on each tires for 928, 959, etc as well as few sedans. They recorded any measurements possibly affect to the tires; temp, slip angles, etc. etc. They estimated fairly accurate FC( of each tire as well as total for a car) on the given day using their math and statistics based on the measurements.

Given FC and a capability, Math guys estimated each corner speed, entry speed, exit speed and then possible best lap time as if a driver executes perfect weight shifts. They also considered the time lag information passing from tire to a driver and his reaction time to another drivers inputs. The team were very happy that their test drivers running close to the theoretical edge of FC and the lap time and their new tire surely showed better FC than others. (CC. If you start from FC with given tire g limit under simple scenario like perfect driver/car setup and not slip-angle, you know you can calculate imaginable lap time. Chris already told you where is the slowest, what happens usual sport cars after the apex and before apex, what need to be before apex, at entry point, etc. I think you get only one theoretical line, when you use this FC. One more thing, FC is not a complete product; you need to have a lot more. Again, Chirs mentioned he measures few more in his car.)

One day, a F1 driver and a F1 candidate (I think) came and drove the cars. Only problem was their lap times was significantly (in statistical term) few second faster then the theoretical possible lap times.

A guy in this project team teaches a professional DE school. His school teaches this FC driven line using surely TB. He believes SIFO line is not just efficient but not that good(safe) to teach neither. He does not like the reduction of FC and greater slip-angle, relative but greater change slip-angle and of weight shift, which increase risk of a spin. The beginners run slow and well inside of FC anyway, he think teaching smooth balance control, constant slip angle and TB inside of FC at the beginning is better than at the edge of FC later.

He also think that students start showing some conversion of lap time and measurable improvements in 500-1000 laps on a given track. Most students reaches fairly close levels around 1000 laps. Then, he think students can start meaningful discussion. Students should just listen to instructors and tires until this level.

Color Change: Now, you know you, I also, drive well inside of FC, not the edge. I do not know how to measure the weight (balance) shift, but you have a equipment to estimate FC and your position relative to an edge of FC. You have better equipped than most of us. You already get some agreement of your approach from few people here, including well respected ones. I do not think you need to sell details of your view on how to run on the edge of FC. Just find a place to run. After you run 1000 laps, you would have better ideas/experiences to share people to reach how to become a driver constantly running on the edge of FC using DA. Most of us need to know how to become a driver to be capable to run on the edge of FC, not to search how to drive the edge of the edge.

M758

Well I STILL think you are approaching this backwards. I am not 100% certain that max g's in every corner will result in the lowest lap times. Yes max g's are important, but not as important as a lap times.

To me being fast is much more than JUST G-sum. There are so many sublties that it just not that simple. There are places on tracks that you need to "go slow to go fast". What that means is that you need to go slower than you think you can to minimize the overall lap time. Ie give-up one conrer for the next or go really deep on a decreasing radius corner. The things are counter to the idea of max speed through all corners. So to ME max g's always sounds like a mantra of max speed through every corner always ( know this Not what you said), but I think clearly you know attempting to that is not the way to best lap times.

I think if you shoot for low lap times as your #1 goal you will be much faster than if you shoot for lots g's. I think 90% of folks here would agree with that.

Bob Rouleau

CC - I think M 75 summed it up nicely. My post points out that our goal as drivers on a race track is to go faster. The FC (and I agree that looking at Lat and Long G's is the friction circle) is a tool used to that end. It's my impression that you are taking a different approach - you are looking to optimize your friction circle performance. It appears that racers who have DAS available strive to go fast and the FC is one of many tools in the arsenal. If car A is faster than me in a segment, I am highly motivated to figure out why - who isn't?

Looking at the dispute between you and Geo, he's saying the FC is not the goal, going faster is. That matches my experience too. I am also pretty sure that everyone here agrees that a DAS is a useful tool for improving lap times and car set up.

My comment about "arguing about minutia" relates to the fact that two guys are looking at the same issue from a slightly different perspective. If I was your instructor, I'd work on smoothness and consistency (maybe you are there already but the video suggests not). Once you had mastered the former, we'd play with lines looking to maximize speed. I do agree that different cars may use slightly different lines. For example a car that can accelerate at 1.0 G (I would love to have one!) might optimize the line to take advantage of this capability over a similar car which can only pull 0.3 G Long. My GT2 versus GT3 experience has shown this to be favorable. Is it optimizing the FC, yes. Your DAS would be a useful tool to optimize performance under the circumstances.

I would not be looking to maximize any particular value of a FC plot initially. I'd used it for fine tuning - which is pretty much what everyone else does. I am guessing that if you had an instructor you had confidence in, you might change your approach and work on the driving, car feel/control etc. and use DAS like the rest of us. In the absence of a good instructor I assume you rely on DAS as the only input (perhaps timing too?).

Regards,

smokey

CC, my 12 point program didn't work, and I'm back. I'd like to put on a moderator hat, and state that everyone here is actually in agreement, and is carrying out an ecclesiatic discourse. CC, you make one statement that proves that everyone is in agreement, to wit: "Maximizing g's in the appropriate direction is the fastest. Always." This is always true, because it's a mathematical tautology. If you maximize g's (acceleration) in the appropriate direction, which by defintion is the longitudinal one, you will maximize speed. Acceleration is the derivative of the speed versus time function, and maximizing it will maximize the area under the curve, as you will know from calculus. Lateral g's are only a means to an end, which is to maximize longitudinal acceleration. Anyway, g's (32 fpsps) are just a measure of acceleration, so we should stop referring to "g sum" and discuss the acceleration vector. Changing terminolgy may also calm everone down.
I pointed all this out in another thread a couple of months ago, and apologize for the repetition, but it's still true: YOU'RE ALL IN AGREEMENT!!!!!!!
The Truth: max longitudinal acceleration=maximum average speed=minimum lap time
Corollary: lateral acceleration is only a means to an end (see The Truth)

M758

Good a good point Smokey
Time for a group hug and a little round of Kumbaya?

Jim Child

I've got to strongly agree with Smokey on this one. Club racing a dedicated track car with the all of the required safety devices is far safer than doing DE's in a TT with major performance mods and no cage. This is even more true for you since you want to drive aggressively and show good DAS results. Bring her to Putnam with you in October, and I'll explain it to her myself. I'll even take her out for a smooth and safe ride in my race car if that would help.

smokey

Let's start a fund to buy cc a 944 spec car. The only price he'll have to pay is to read all of his posts here after he has raced it for two years. HWFMR, are you there to organize the fund-raising? Jim Child is in charge of negotaitions with swmbo.

Greg Fishman

Fund raising? Just sell a set of wheels for the 996 and you could buy a 944 already prepped.