How to develop an F1 car?

[Jersey Tom]

A lot of racecar vehicle dynamics are pretty simple, at the base level. The trick is breaking it down into simple pieces.

Kinda depends what you're trying to figure out exactly.

[speedsense]

Good data is essential for chassis and "race package" development (e.g. 7-post testing), but you're not going to win championships with it by itself. You need a good driver that gives good feedback, coupled with a good team of engineers.

I completely disagree with this statement. Having been involved in 7 championships in assorted cars, teams and drivers. One championship stands out, as the driver could not tell if the car was oversteering (sometimes it was so bad, it was a wonder he kept it on the track, and he said afterwards the car was fine, the data showed it wasn't) or understeering except when it was so bad he couldn't drive it.
The driver's car control and talent was so high, it didn't matter what his car handled like, he drove around it. It was only the data, that told us otherwise, when the car wasn't good and it was the data that allowed us to make the car right.
IMHO, your statement doesn't ring true. Championships can be won without driver feedback and have.....

I don't think 'oversteer' is as simple as you put it, particularly since 'oversteer' or a 'loose' racecar can encompass a lot of things when the driver communicates it. The Ackermann corrected steering angle thing is hokey at best, and pretty poor IMO aside from some specific instances or as a really quick and dirty tool.

All oversteer is followed with a correction of the steering wheel, the amount of the correction is directly related to whether the car stays on the track and whether the car's attitude is neutralized. Oversteer is never a steady state condition and to the driver, a neutral car is never the same for two drivers.
The Ackerman corrected steering angle math channel, is only one route to analysis. And actually it's foundation or creation was to help define understeer originally with oversteer definitions following with it. Speed adjusted steering angle is another. They are many techniques, to get to a reliable analysis and there is many uses of assorted sensors to arrive at accurate answers.
Analysis itself has very little impact on a race team's performance when it the analysis is solely done in absolute numbers. It may satisfy an engineer's equations but when it comes to analyzing driver technique and handling situations and their causes, many more techniques which highly impact the team's results are employed. These are based in comparitive and separation analysis and define well beyond absolute numbers, what the causes are.

For example, if the driver has the car mid corner and is slightly sawing at the wheel, your data trace for "oversteer/understeer" will be oscillating just as much as the steering trace is, even though the tires are saturated and the trim of the vehicle isn't really changing.

One must first understand the difference between tire slip angles and sliding the car (though slip angle does have a sliding effect within the contact patch but explainations are for another thread).The terms "saturated" and "trim" should be replaced with slip angle and rotation or attitude. Which can be measured though several different routes, depending on the availiablity of sensors. ALA-optical sensors (for lateral ground movement under the tires), tire pressure-temp sensors (calculating tire compression), ride height sensing and suspension sensors for roll. As a grouping for example, the more background information you have, the clearer it becomes (tire slip measurement machines, tire spring rate numbers etc.)
The holy grail of chassis setup, is knowing an accurate answer to the unanswerable, exact measurement of "real time" tire deflection.
To fully answer your question, my data analysis will understand more (than the driver can recall) about the condition you describe and what the causes of the "sawing" of the wheel are. IF they are likely-Chassis induced (including tires), driver induced or track induced. And whether they are costing or improving laptime. It is locating the cause that gives data it's power.

Or, in some forms of racing you might have an asymmetric vehicle setup where the car is at some non-zero sideslip angle while going down the straight, even so much that the wheel is significantly off center. In that event you have "static" oversteer even if the car is going down a straight line.. which is kind of an odd concept.

Oversteer is never a "static" condition. The only poor handling condition that "approaches" static is understeer (can maintain a constant Lateral G in most cases) If I understand correctly, you are describing an off-set track. Not the impossible, oversteer in a straight line.

Or there's the question of separating 'text-book' slip angle oversteer, from just high yaw attitude, to over-rotation. Which is most important for the driver? How do you even accurately measure accelerations in the "ground" plane when you have chassis roll in combination with changes in corner banking, bouncing off curbs, etc?

slip angle oversteer? If the car's attitude is within the slip angle of the tires, it's not oversteer. I think your trying to state a drift, which is within the traction circle and is what all engineers are trying to achieve
High yaw attitude- means many things, some good, some not so good...
Over rotation- bad driver [-X , bad car [-X or a combination of both. Accurate data analysis can tell which one is happening, in almost all cases of the above.

"..ground plane.."- answered above...under "optical sensors".
Yaw can be determined through it's rate, with yaw sensors and can be sensed through GPS, accelerometer signals on the front and rear of the car.
Thirdly, as a data person, I tend to understand where every bump (even new ones from the year before), curb, bank etc. better than most drivers do. You forget,my vision is at 100-1000hz when the drivers vision is at less than 20hz.
Not only can I tell you whether the car is within it's slip angle, and how much, I can also tell you what the front and rear, roll, heave, pitch, warp, yaw angle, tire compression, ground plane slip angle, steering angle, throttle, rpm, speed, lat-long G and many more for every mm of the race track. Never seen a driver come close to relating even 1% of that.

Not to mention many of the data channels inevitably get very noisy. What's real? What isn't?

Depends on the system and how good it is. Some systems have pretty much removed enough noise that it no longer intrudes into the data. With the coming optic fiber wiring movement, noise may become a thing of the past. RF noise, magnetic fields intrusion have long since been reduced with the good system's design. Sensor noise, mainly is based in the quality of the sensor used.

Track testing time is always at a premium. A cognizant driver with good communication skills will always be essential to developing the best race package, and getting the most stuff done in the shortest amount of time.

What used to take two, three or four days in testing, can now be done in one day with a data system attached. What used to take an entire racing weekend to find, through the drivers recall, can now be found correctly in data in one fast lap.

Sorry, not convinced by your aguement, driver's recall importance is getting drowned out and replaced by accurate data analysis....IMHO

[speedsense]

BTW, I am not saying that driver's recall isn't used anymore, it is. Though in 1988 (assumed pre-data era), it was far more important that the driver's duties and abilities, were included at top of the list, recall.
As data analysis has progressed, recall and chassis setup knowledge has digressed as far as how important it is to have such an ability. It is the advancement of data analysis, simulations and technology that has removed that importance and replaced it to the point that a driver without good recall or setup knowledge can compete with those that do have that skill, provided they have a good backing in data analysis.

Sure. But it's one thing to just compete with the top dogs.. to be in the same field. It's another to win races, and yet another to win championships.. especially with tires, aero components, etc changing every week.

The sharp driver / engineer combination will make progress faster than just engineers by themselves. The whole idea is to get ahead of your competition and win races. I say it's still absolutely essential to have the driver in the process.

Plus there are some pro series where you are banned from having ANY telemetry on race day, in which case you damn well better have good driver/engineer communication. If you come in expecting to just go off data.. you're hosed.

You misunderstand me, I never said the driver's input wasn't important. Just that the ability for a driver to have good recall isn't as important as it once was, and that it's because of data acquisition that has made this possible.
In the old days of racing, it was vital that the driver had great recall to be a great driver. Today, it's no longer vital that a driver has good recall when there's a data system to do that job. The driver can't even approach the information that is gained. And the driver that doesn't have that ability can win races, without it.

Even the series that doesn't allow data have cars winning that are using data on test days to capitalize on what happens at the race track. Look at Nascar, for instance. On race weekends, setup changes are based in driver feedback, but the top teams are using simulation programs and engineers running them (if they have data from testing at that track or one like it) to resource from. It exists there too. And even here the driver's recall is still being based from data that's been acquired. Why do you think some cars have coil bind figured out and some don't. One clue- it's not the driver's feedback, it's that 100 sensor data system sitting back at the shop....

[Jersey Tom]

Top NASCAR teams do run extensive simulation to know how to start their setups, and what changes will do what to the car.

But even then, when the car comes in and some change has to be made during the race, there is no telemetry. No data to help you. Clear accurate communication between the driver and crew chief is all there is. Knowing what setup change will have X effect on the car does you no good if the driver can't tell you what's going on.

Maybe my thinking on this is skewed as oval racing is what I'm most used to.

Also not sure what you mean by "if the car is within it's slip angle"

[Scotracer]

A lot of racecar vehicle dynamics are pretty simple, at the base level. The trick is breaking it down into simple pieces.

Kinda depends what you're trying to figure out exactly.

Yeah, for an engineer they are far too simplistic. They try to cover too many topics too thinly.

I'm mainly trying to improve my knowledge of suspension and tyres; rolls centres, damping rates, slip angles etc etc.

[Jersey Tom]

Are you interested in that sort of thing as in.. what each one does for tuning a car? Or what?

[speedsense]

Top NASCAR teams do run extensive simulation to know how to start their setups, and what changes will do what to the car.

But even then, when the car comes in and some change has to be made during the race, there is no telemetry. No data to help you. Clear accurate communication between the driver and crew chief is all there is. Knowing what setup change will have X effect on the car does you no good if the driver can't tell you what's going on.

Maybe my thinking on this is skewed as oval racing is what I'm most used to.

Also not sure what you mean by "if the car is within it's slip angle"

Sorry,if I'm typing in a confusing manner, how about stated "if the car's attitude is within the slip angle of the tires...
A lot of people, including drivers confuse the difference between sliding and slip angle and also drifting and sliding the car. There are major differences between those terms.
My understanding of the terms you use in description, it seems you relate to an Oval car more so than a road race car. So I'll describe this in that vain.

A tire slip angle, is the elastic ability of the contact patch (tire contact with the ground) and it's relationship to the actual path of travel of the wheel. (we'll use the rear tires for this, so as to not complicate by steering). On an oval the "path" or direction of the wheel is narrower to the left, than the path that the tire contact patch is contorted to. This variance, on a Cup Goodyear tire is approx. 7 degrees (pointed to the outside of the turn), when it is pushed to the limit of adhesion.
A simple way to see this, is to draw two parallel lines, top and bottom on a ballon, add a consistant downward pressure, and turn the ballon against the ground. The two parallel lines will no longer line up. The one on the floor will be turned to the outside. If you continue to add more twisting action, eventually you will "break" the grip to the floor. You have reached the limit of adhesion. As you twisted before it broke lose relates to the slip angle on a tire. When it broke lose of the floor, it would be the same as a loss of traction or a slide..
Now if you involve all four tires on a car, all at their maximum slip angle (this can be slightly different front and rear) the car from an outside observer, who would regard the car as sliding, due to it's attitude being different from it's path.
This is a drift. The car is at maximum grip, but not sliding, though the path appears as though it is, to the outside observer. This is the difference between a drift and a slide.
And what I meant when I said, within the cars slip angle.
Loose (Oversteer) is a sliding condition, drifting a car with a slightly greater slip angle in the rear than the front, is NOT loose (oversteer), but infact well within the grip level of the car and due to the differences of the properties of the front and rear tires.
BTW, this happens frequently in cup cars as the rear suspension (live rear axle) is not anything like the indepentent front A Arms. And the suspension imposes a different slip angle than the front (which also has steering). Plus the tire sizes front and rear are not the same, hence the different slip angles do to construction of the tires.

But even then, when the car comes in and some change has to be made during the race, there is no telemetry. No data to help you. Clear accurate communication between the driver and crew chief is all there is. Knowing what setup change will have X effect on the car does you no good if the driver can't tell you what's going on.

Yes and no. You have spotters and crew who can "see" the car all the way around on an oval. So the driver is not completely on his own with his description of the handling situation.
And the teams that don't test, especially the ones that test without data acquistion, don't win very often like the ones that do test and use data systems. Their decisions are much more reality based and with much more knowledge of what changes will do what and why. "Off the Cuff" racing or testing, without data acq. or some sort of data collection and analysis, will always provide "Off the cuff" results, no matter how good the driver is at recall or engineering his own car.
The guys who win often and consistantly are doing so, because of their background work with data collection. Guys like Jimmy Johnson and Knaus have their heads in their computers and in data acquisition when they are allowed to use it. And at the races, they also are referring to a simulation program, either Adams, Pi research, Chassis Sim or Miliken simulation programs running in the background (some trailer at the track) with the changes proposed getting run through the sim BEFORE they change the car. IMHO

[speedsense]

A lot of racecar vehicle dynamics are pretty simple, at the base level. The trick is breaking it down into simple pieces.

Kinda depends what you're trying to figure out exactly.

Yeah, for an engineer they are far too simplistic. They try to cover too many topics too thinly.

I'm mainly trying to improve my knowledge of suspension and tyres; rolls centres, damping rates, slip angles etc etc.

Try this SAE book. A great study in vehicle dynamics and enough math/theory to wet your whistle-

Race Car Vehicle Dymanics by Milliken/Milliken

Another more recent one, also SAE

Race Car Engineering- by Warren J Rowley, with Computer Gurus, WM.C.Mitchell and J.J. Salinas, PhD, Peng- Mathmatical Modeling and Engineering consultant...

excellent reads, both of them...

[Scotracer]

A lot of racecar vehicle dynamics are pretty simple, at the base level. The trick is breaking it down into simple pieces.

Kinda depends what you're trying to figure out exactly.

Yeah, for an engineer they are far too simplistic. They try to cover too many topics too thinly.

I'm mainly trying to improve my knowledge of suspension and tyres; rolls centres, damping rates, slip angles etc etc.

Try this SAE book. A great study in vehicle dynamics and enough math/theory to wet your whistle-

Race Car Vehicle Dymanics by Milliken/Milliken

Another more recent one, also SAE

Race Car Engineering- by Warren J Rowley, with Computer Gurus, WM.C.Mitchell and J.J. Salinas, PhD, Peng- Mathmatical Modeling and Engineering consultant...

excellent reads, both of them...

I already have Milliken/Milliken. It's alright...but most of the stuff in it I already knew. Woops. I'll have a look at the other one, though.

[Scotracer]

Are you interested in that sort of thing as in.. what each one does for tuning a car? Or what?

Well I am an engineer hoping to get into motorsport at some point (and currently working in the automotive industry anyway) so I should really know that stuff. Anything else I can add to my CV as skills or understanding, the better.

Oh and I do hill-climb racing with a friend so it would be useful for real world too

[Giblet]

Race Tech magazine this month has a good article on steering setup.

[Jersey Tom]

Sorry,if I'm typing in a confusing manner, how about stated "if the car's attitude is within the slip angle of the tires...
A lot of people, including drivers confuse the difference between sliding and slip angle and also drifting and sliding the car. There are major differences between those terms.
My understanding of the terms you use in description, it seems you relate to an Oval car more so than a road race car. So I'll describe this in that vain.

A tire slip angle, is the elastic ability of the contact patch (tire contact with the ground) and it's relationship to the actual path of travel of the wheel. (we'll use the rear tires for this, so as to not complicate by steering). On an oval the "path" or direction of the wheel is narrower to the left, than the path that the tire contact patch is contorted to. This variance, on a Cup Goodyear tire is approx. 7 degrees (pointed to the outside of the turn), when it is pushed to the limit of adhesion.
A simple way to see this, is to draw two parallel lines, top and bottom on a ballon, add a consistant downward pressure, and turn the ballon against the ground. The two parallel lines will no longer line up. The one on the floor will be turned to the outside. If you continue to add more twisting action, eventually you will "break" the grip to the floor. You have reached the limit of adhesion. As you twisted before it broke lose relates to the slip angle on a tire. When it broke lose of the floor, it would be the same as a loss of traction or a slide..
Now if you involve all four tires on a car, all at their maximum slip angle (this can be slightly different front and rear) the car from an outside observer, who would regard the car as sliding, due to it's attitude being different from it's path.
This is a drift. The car is at maximum grip, but not sliding, though the path appears as though it is, to the outside observer. This is the difference between a drift and a slide.
And what I meant when I said, within the cars slip angle.
Loose (Oversteer) is a sliding condition, drifting a car with a slightly greater slip angle in the rear than the front, is NOT loose (oversteer), but infact well within the grip level of the car and due to the differences of the properties of the front and rear tires.
BTW, this happens frequently in cup cars as the rear suspension (live rear axle) is not anything like the indepentent front A Arms. And the suspension imposes a different slip angle than the front (which also has steering). Plus the tire sizes front and rear are not the same, hence the different slip angles do to construction of the tires.

Well.. I am a tire engineer, so I do have a pretty decent grasp on the concept of a slip angle

The 'classic' definition of under- or over-steer, as you'd read in RCVD or what have you, is just the difference in front and rear axle slip angles. Doesn't necessarily have to be at the limit of traction (plow/spin). Can be linear range through transitional up until tires on one or both axles saturate.

Still don't see what you're saying about a car being "within its slip angle." That phase has no meaning to me. Tires are always at some slip angle, and the chassis always has some sideslip angle. Do you mean the car acting within the limit of traction, with the tires not fully saturated? Either way, you can have under- or over-steer anywhere in the range of vehicle handling.

With the Cup car as a good example, even going down a straight line at Ay = 0, the front and rear tires are at significantly different slip angles. If the rears are at a higher magnitude than the fronts, technically the car is at an "oversteer" condition. It makes for an.. interesting handling feel from where the car starts at 0 Ay, then progresses as lateral g's build up, and finally gets to ultimate trim. That's why I'm saying it's a bit difficult in pinning down 'balance' to a number or set of numbers. How much of the driver's perception of balance is absolute steering and sideslip angle.. versus how they build up with turn-in.. versus rotation.. versus ultimate trim.

Btw, front and rear tires are same size. And you may want to check your slip angle numbers.

Yes and no. You have spotters and crew who can "see" the car all the way around on an oval. So the driver is not completely on his own with his description of the handling situation.
And the teams that don't test, especially the ones that test without data acquistion, don't win very often like the ones that do test and use data systems. Their decisions are much more reality based and with much more knowledge of what changes will do what and why. "Off the Cuff" racing or testing, without data acq. or some sort of data collection and analysis, will always provide "Off the cuff" results, no matter how good the driver is at recall or engineering his own car.
The guys who win often and consistantly are doing so, because of their background work with data collection. Guys like Jimmy Johnson and Knaus have their heads in their computers and in data acquisition when they are allowed to use it. And at the races, they also are referring to a simulation program, either Adams, Pi research, Chassis Sim or Miliken simulation programs running in the background (some trailer at the track) with the changes proposed getting run through the sim BEFORE they change the car. IMHO

I realize the way Knaus and friends work. Yes, they do lots of up-front simulation with a large engineering staff. They know what adjustments will do what, ahead of time.

But STILL, when it comes time to make the change, you have to know what problem you're trying to address! Crew chief may have a list that says..

Change A -> Balanced car earlier in run, with poor trim later
Change B -> Poor trim and grip earlier in the run, with peak balanced grip late
Change C -> Frees car up everywhere
Change D -> Tightens car on-throttle
Change E -> Makes car less sensitive to forward/rear load transfer
Change F -> Makes car more sensitive to load transfer

Etc. Even with all that, it is STILL up to primarily the driver to communicate specifically what is happening with the car, where on the track, and under what inputs, so the chief can pick the best 'play' to run.

Good example of this is with Dale's setup. Very talented driver. Excellent engineering staff. Not winning championships, or even many races. May start strong and then falls back. Big change since his new crew chief in how he's giving information back during a run. He's even using numbers to describe it now!

Certainly good data is what puts ya way ahead of the curve. No denying that. IMO, the driver feedback is still a critical feedback parameter. Can't just do it with engineers. I suspect that's one reason Claude, in all his wisdom, wasn't particularly successful in Cup.

[speedsense]

Well.. I am a tire engineer, so I do have a pretty decent grasp on the concept of a slip angle

The 'classic' definition of under- or over-steer, as you'd read in RCVD or what have you, is just the difference in front and rear axle slip angles. Doesn't necessarily have to be at the limit of traction (plow/spin). Can be linear range through transitional up until tires on one or both axles saturate.

Still don't see what you're saying about a car being "within its slip angle." That phase has no meaning to me. Tires are always at some slip angle, and the chassis always has some sideslip angle. Do you mean the car acting within the limit of traction, with the tires not fully saturated? Either way, you can have under- or over-steer anywhere in the range of vehicle handling.

With the Cup car as a good example, even going down a straight line at Ay = 0, the front and rear tires are at significantly different slip angles. If the rears are at a higher magnitude than the fronts, technically the car is at an "oversteer" condition. It makes for an.. interesting handling feel from where the car starts at 0 Ay, then progresses as lateral g's build up, and finally gets to ultimate trim. That's why I'm saying it's a bit difficult in pinning down 'balance' to a number or set of numbers. How much of the driver's perception of balance is absolute steering and sideslip angle.. versus how they build up with turn-in.. versus rotation.. versus ultimate trim.

Btw, front and rear tires are same size. And you may want to check your slip angle numbers.

Whoops, forgot that fact, the front and rear tires are the same size. Been a while since I worked in Cup.
As you are a tire engineer, your world is different than mine as are your observations. I have never considered the slip angle of the tire down a straight away or that in terms of setup, except in the aero advantages of tire compression on a straightaway and downforce removal, though it's not something that I can use to manage setup except in tire pressure.
As far as the U/S, O/S observations, they also are correct though as someone setting up a race car, the concern would be with anything underneath and above the maximum slip angle of the tire, what ever that is to applicatable tire. Hey, wait you would know the answer to that, care to tell the spring rates and slip angles of a Cup tire? Sorry, had to get that in...having dealt with tire engineers before, always trying to pick their brains for info.

I realize the way Knaus and friends work. Yes, they do lots of up-front simulation with a large engineering staff. They know what adjustments will do what, ahead of time.

But STILL, when it comes time to make the change, you have to know what problem you're trying to address! Crew chief may have a list that says..

Change A -> Balanced car earlier in run, with poor trim later
Change B -> Poor trim and grip earlier in the run, with peak balanced grip late
Change C -> Frees car up everywhere
Change D -> Tightens car on-throttle
Change E -> Makes car less sensitive to forward/rear load transfer
Change F -> Makes car more sensitive to load transfer

Etc. Even with all that, it is STILL up to primarily the driver to communicate specifically what is happening with the car, where on the track, and under what inputs, so the chief can pick the best 'play' to run.

Good example of this is with Dale's setup. Very talented driver. Excellent engineering staff. Not winning championships, or even many races. May start strong and then falls back. Big change since his new crew chief in how he's giving information back during a run. He's even using numbers to describe it now!

Certainly good data is what puts ya way ahead of the curve. No denying that. IMO, the driver feedback is still a critical feedback parameter. Can't just do it with engineers. I suspect that's one reason Claude, in all his wisdom, wasn't particularly successful in Cup.

[/quote][/quote]
I doubt Claude had percieved not using the front springs on a race car, and running a race car with no front suspension working..not good on normal engineering brains, or tire engineers for that matter. Oval track racing in general, which I do have a lot of open wheel and some Cup, Truck experience with, is a very different world to live in and very different in terms of setup when compared to road racing. Oval track is much more about chassis setup than driver than road racing is. Though many may disaggree when talking about F1, I still beleive that Oval cars have a higher percentage of car setup dominance than driver input. Which in oval racing, makes data acquisition even that much more important.
And that Cup racing is similar, to the days of old in F1 when data didn't exist, and the driver's had to have an ability to retrace and recorded their own data in their heads.
However, as this thread is about F1, that recall isn't as important, as data has done the job much better than any human brain can do. The same thing would happen to Cup racing, if they were to allow data on race weekends. It would make the cars closer, your job easier and less about the driver input... though I don't think we'll ever have to worry about that happening.