Post rigs

[Smokes]

Diff maps are nice... except when your diff has no adjustment which is the case in many series.

Trying to play with tire temps to fix a problem of roll stiffness, camber, or steer imbalance... IMO is just putting a bandaid over an issue and not really solving the root problem. Tune the right thing with the right 'tools.'

Does changing spring rates impact your damping? Of course! That's again, why I say set your roll stiffness split and (most of) tire pressure first, to get the average corner loads right, then go to dampers to play with TLV.

It's one thing if you have designed and built the chassis (e.g. F1) and have a pretty good idea of where everything is set.. and you're just doing fine tuning. How often is that the case though? GP2, IRL, Indy Lights, NASCAR... all are supplied chassis. If I'm handed a chassis, I want to know as much about the car from a mechanical standpoint first off.

But again.. just my way of thinking about it. I live more in the K&C and F&M realm.

hi Tom you should really state what class it is applicable to and what tyres and what the rules allow and do not allow. As Dave W is probably coming from high technolgy F1 propective and you are coming from a very resrictive rule propective.

With Rescitive rules K&C will give you a edge when it comes to setup gains. As you can simulate the car behavious to see how the car behaves depenant on setup change.

But you could have the best setup in the world but it could also be the slowest if the driver cannot utilise it due to there driving style case point Schmacher (rear rotation) and Rosberg (???)or Button(Smooth) and Hamilton (Agressive).

[Jersey Tom]

Knowing the kinematic and force rates of your suspension is critical regardless of what series you're in... all the way from pro open wheel and stock car down to FSAE.

The difference is... in F1 you're designing the kinematic rates and with good manufacturing, the pure kinematics should be close to what you've designed. Compliances are another story. Or, if you have a spec chassis in use for a number of years (IRL, Champ Car...), your tub hard points aren't going to change and the range of kinematics are pretty well established. Not going to be different year to year.

But you can't just assume that K&C info is a given, particularly for Belatti's first inquiry. Rank order of importance I still put it before shakers.

Either way, without tire or aero maps, neither K&C nor 7-post data will let you quantitatively say how significant a change is. Even in one of the SAE papers posted earlier on in the thread, the point was made in that example that you could basically choose to minimize the pitch response OR heave response of the car. Can't say which is more significant without more data.

[Smokes]

Either way, without tire or aero maps, neither K&C nor 7-post data will let you quantitatively say how significant a change is. Even in one of the SAE papers posted earlier on in the thread, the point was made in that example that you could basically choose to minimize the pitch response OR heave response of the car. Can't say which is more significant without more data.

I thought the tire and aero map could be mathematically taken into account on a K&C or Shaker rig, but are talking about virtual simulation not real simulation there fore with virtual you have to discount some of the realitys to simplify the simulation.

Usually all setups will compromise the handling 'charecters' of the car and the setup is the best compromise for the track and tires.

[Jersey Tom]

I thought the tire and aero map could be mathematically taken into account on a K&C or Shaker rig, but are talking about virtual simulation not real simulation there fore with virtual you have to discount some of the realitys to simplify the simulation.

Not following what you're trying to say.

Short answer though... no. They're not inherently taken into account.

Longer answer - on a K&C rig you can measure a camber curve, but what does that really tell you without knowing how camber sensitive the tire is, or where you want it to operate?

Same with 7-post... suppose from your testing you know you have a range of damper rates that really minimize the response of the pitch mode of the car, and a different range that minimizes the heave response. If you don't have aero data that shows which is more important.. you have nothing to base your setup choice on with regard to controlling chassis attitude.

This is why in my 'order of importance' I put tire data before K&C, and wind tunnel before shaker.

[marcush.]

a bit off topic but I always thought ththaz testing a tyre on the track with fully adjustable cambers /slipangles and vertical loads and all this on the fly monitoring forces transmitted would be the starting point for a decent development programme...of course this would be a quite elaborate vehicle..

[Jersey Tom]

a bit off topic but I always thought ththaz testing a tyre on the track with fully adjustable cambers /slipangles and vertical loads and all this on the fly monitoring forces transmitted would be the starting point for a decent development programme...of course this would be a quite elaborate vehicle..

Like this?

[DaveW]

As Dave W is probably coming from high technolgy F1....

He isn't, actually. He helps race teams ranging from FFord upwards as a (more or less) full time business, executing & analysing relatively simple "hardware in the loop" tests quite well (he likes to think). That does not include "track simulations" (often called "seven post" tests, just to add confusion to an already confused world).

This is why in my 'order of importance' I put tire data before K&C, and wind tunnel before shaker.

I would accept "order of execution", perhaps....

The fact is, most of my customers are fairly regular, & I am reasonably certain that few carry out K&C tests (or would know how to interpret fully the results from such a test). So far as I am aware, only NASCAR teams carry out K&C tests (or equivalent) on a regular basis & there are quite specific reasons for that.

[marcush.]

a bit off topic but I always thought ththaz testing a tyre on the track with fully adjustable cambers /slipangles and vertical loads and all this on the fly monitoring forces transmitted would be the starting point for a decent development programme...of course this would be a quite elaborate vehicle..

Like this?

[-o< [-o<



yes and no question is will you be allowed to run that device on your track and how do you relate this to real life cornering speeds?

[Jersey Tom]

The fact is, most of my customers are fairly regular, & I am reasonably certain that few carry out K&C tests (or would know how to interpret fully the results from such a test). So far as I am aware, only NASCAR teams carry out K&C tests (or equivalent) on a regular basis & there are quite specific reasons for that.

For sure. I don't doubt it. Do most of those 'regular' customers have a spec or purchased chassis (as opposed to built in-house)? If so... and you can't really change your 'K' or 'C'. But still, even if that data is already well-established.. doesn't make it less important.

Bottom line, K&C data goes into any sort of vehicle sim or up-front setup you're gonna do... steady state, open or closed loop. If you don't know what your steady state camber and slip angles are, you're totally out to lunch. Personally I think interpreting K&C data is easier than interpreting 7-post data, but that's just me

[-o< [-o<



yes and no question is will you be allowed to run that device on your track and how do you relate this to real life cornering speeds?

The issue of practicality definitely arises.

[DaveW]

Do most of those 'regular' customers have a spec or purchased chassis (as opposed to built in-house)? If so... and you can't really change your 'K' or 'C'.

Exactly.

I suppose most of my customers have purchased spec. vehicles. However, I do see bespoke Touring, GT, LMP & F1 vehicles, & I have occasionally caused spec. designs to be modified via my customers after an interesting rig test. I have even helped to validate a mathematical simulation model. Having said that, I wouldn't wish to over-sell what I can accomplish. Like all else, rig testing (as I do it) is a tool. It can't reveal the whole picture, but neither can anything else - as you yourself suggested. It can do considerably more than simply arbitrate on contact patch loads, however.

Bottom line, K&C data goes into any sort of vehicle sim or up-front setup you're gonna do... steady state, open or closed loop. If you don't know what your steady state camber and slip angles are, you're totally out to lunch.

Agreed, but lunch is not necessarily on the table if you do "know what your steady state camber and slip angles are."

[DaveW]

a bit off topic but I always thought ththaz testing a tyre on the track with fully adjustable cambers /slipangles and vertical loads and all this on the fly monitoring forces transmitted would be the starting point for a decent development programme...of course this would be a quite elaborate vehicle..

Good idea, Marcus, but I have seen a towed "machine" designed explicitly for that purpose rip the compound off a slick tyre without achieving anything like a realistic operating temperature. I imagine that would (or could) also be true for a tyre test rig such as the TIRF.

[marcush.]

a bit off topic but I always thought ththaz testing a tyre on the track with fully adjustable cambers /slipangles and vertical loads and all this on the fly monitoring forces transmitted would be the starting point for a decent development programme...of course this would be a quite elaborate vehicle..

Good idea, Marcus, but I have seen a towed "machine" designed explicitly for that purpose rip the compound off a slick tyre without achieving anything like a realistic operating temperature. I imagine that would (or could) also be true for a tyre test rig such as the TIRF.

brings me to a fully adjustable(via servohydraulics) testhack you can preprogramme and gather data on the fly with all cambers , toe ,vertical load distribution and tyre pressures adjusted on the fly...

[DaveW]

brings me to a fully adjustable(via servohydraulics) testhack you can preprogramme and gather data on the fly with all cambers , toe ,vertical load distribution and tyre pressures adjusted on the fly...

Yes... but wouldn't the result be rather like a track test - a fairly arbitrary & uncontrolled slice through a many-dimensional surface? If so, extracting anything systematic from the results would require much sorting, averaging & faith....

[ghost406]

I suspect a few F1 teams would like reliable aero maps...

Tyre load variations... like many parameters (including some aspects of aero), it isn't necessary to know absolutes, just whether a set-up change has made an improvement or otherwise. Tyre heat rate is interesting. I have computed it for several years without being entirely convinced of its value, but then this year I received direct feedback for one vehicle, at any rate, that rig predictions were reflected reasonably accurately (on a relative basis) during track tests. BTW, there is a little more to tyre heat rate than CPL variation - tyres are non-linear, as you well know & changing damping "style" can increase heat rate, reduce CPL variation & increase minimum CPL values.

I find it interesting that you don't appear to consider dampers important in setting up a race vehicle, except to manipulate steering transients. That would explain why I was unable to change your mind (why was I not surprised?). Belatti is correct, however. Optimizing damper settings can & usually will improve lap times significantly. Very simplistically, dampers provide mechanical performance, whilst springs, bars & damping style help a driver turn mechanical performance into lap time.

p.s. It hasn't been my intention to denigrate K&C tests. Far from it...

Hello,
How do you calculate Tyre heat rate?
Thank you
Regards

[marcush.]

brings me to a fully adjustable(via servohydraulics) testhack you can preprogramme and gather data on the fly with all cambers , toe ,vertical load distribution and tyre pressures adjusted on the fly...

Yes... but wouldn't the result be rather like a track test - a fairly arbitrary & uncontrolled slice through a many-dimensional surface? If so, extracting anything systematic from the results would require much sorting, averaging & faith....

dave ..you know as well as me that performance does not grow on trees and performance does not suddenly peak at one point and drops off like a stone on bth sides of the peak..So you can very well and quickly adjust for performance ...even though I´m aware this is a bit more complicated than adjusting brake balance..I´m pretty sure a competent F1 driver is able to adjust 4 to 5 parameters on the fly finding the right compromise.they play around with
brake bias ,throttle maps diff settings you name it ...give em cambers and toe and they will find a ways to go quicker.

I´m not talking of sutil who did not even realise he had a mixed set of tyres mounted on his car.. I´m sure after this statement in FI nobody is listening to his comments on setup anymore...