new audi le mans car

[quattro84]

Personally I'd always want to put any offset mass to the inside, but that might just be empirical reasoning. Any oval type car benefits from offset, so it's not unreasonable to say that the predominant direction of turn would be the way to "lean". I have to say I'm pretty sure I've seen a lot more RHD cars on right handed circuits than LHD, the only exception being touring type cars which I concluded was more down manufacturer choice.

Indeed the fin is in the rules now, supposedly another attempt to stop the cars flying by getting sideways. There are always conflicting views on how to stop that - the bevelled underbody was meant to provide something more like an inverted wing profile in a sideways aspect, but there have been others suggesting that a "splitter" edge and an undercut scallop in the bodywork immediately above it would provide a superior solution. But rules are rules.

Interesting read.. more info about this? You work for RTN?

[Keeper of The Kitten]

I did yes, until RTN was shut down in 2008 - it's now the Lotus F1 team (that's the team which ran in F1 last year, not the new "real" Lotus which is the new name for the Renault team).

Reason I say what I said about offset mass and driver position goes something like this:

Car mass is all above ground - and assuming the limits of grip have not been reached, the car will try and overturn around a point centred approximately at the contact patch of the outer tyres (on a right hand turn, that's the left side tyres).

To counteract this, mass offset to the right will increase the reaction force (think in terms of a longer lever imparting more torque).

If you want to see the most extreme examples of cars with offset mass, look at the ISMA Supermodifieds that race on left-handed ovals in America - they place 70% of car mass on the left side for this very purpose.

In other circumstances I would say placing the driver mass in the centre would be more suitable for circuit racing with left and right corners, but where the driver must be offset by regulation (as is the case for LMPs) then I would still prefer to offset the mass to the side which offers the predominant advantage.

[Keeper of The Kitten]

In fairness there is also mass in the theoretical passenger position in LMP, usually the car battery and some electronics, but not as much mass as the driver. Of course, setting the car up with driver mass simulated and trying to get something like equal corner weight at least on the front wheels, is beneficial. But I still maintain that if there is any mass offset, I want it to the right on a right-handed circuit!

[GT500]

Martin, I respect you and you have a serious amount of experiance working with race cars but I have to disagree with driver weights being good on the inside. When I have changed corner weights whilst testing the more the left gets the more grip comes. MOre weight on the loaded tyre gives more grip, taken to an extreme a car with wings corners with more grip. More weight on the tyres.
Gocart drivers lean outwards and move their weight to the left side for a right hander (by clenching the left buttock muscle,so i'm told!)

I usually set my corner weights to get as much on the left front as I can without going mad even when it changes a perfect weight balance on the front...
I know the yanks do the offset thing but I can only assume the banked tracks have another affect there.
Works very well for me and better results managed by my customers!

Just a my 2p!

[Keeper of The Kitten]

I have no problem with that - if it works for your application, and you've tested it, then it works!

I would actually say it depends enormously on what you've got to play with - and you might be finding that placing more weight is getting more heat into the tyres that you need to work the most, but you'll know what tyre temperature distribution you're getting.

As for the Supermods, they do race on tracks ranging from slightly banked to nearly totally flat, with huge wings (which flex down at speed) and very large slicks with stagger. In the past there was even an attempt to run one car (maybe in SRL Supers, I can't remember) with three wheels on the right side and one on the left side, and if the tyres can be made to work up to temperature, that would provide a huge amount of grip to the right side. Needless to say, it was banned.

It's a bit like wide rubber in colder conditions, getting more camber on and making a small part of the tyre operate at the right temperature can sometimes be better than trying to make the whole tyre work at sub-optimal temperature, yes?

[GT500]

Yes!
Most stuff I work on and race are Caterhams, MGs and Radcals.

Another lhd point which I go along with is the actual postioning of the car for the corner. Sat on the left and coming up to the 70% of most tracks right hander you get very close to the edge of the tarmac then turn in and clip where ever and then aim for the exit ,again being able to get up to the edge with a better view.. If that makes sense!

[Keeper of The Kitten]

F3 was my thing before the prototypes (we built our own cars in the TOM'S days, it's so rare to find anything other than a Dallara now - come to think of it, do Dallara still make the Audi LMP chassis? I used to spit feathers at the people who said the Bentley was just another Audi with green paint, we actually did our own tubs - I care a little less now but it's still a bit irksome...)

F3 tyres were like lumps of stone though, and getting heat into them was a bit of a task in those charming winter tests...

I do take that point of seeing the limits of the exit, but I guess that's a "feel" thing when you can't actually see the edge, Jimmy Clark was rather good at it in a Cortina I believe! But when you have to place the driver lower and feeling the extremities of the car is a matter of judgement, then the physics of what the car wants to behave like will surely prevail.

If tyres are sticky and the grip levels are there, I still vouch for keeping the car flatter in aspect - if you're cornering hard the weight is pretty much on the outer tyres already, and I'd like the car to behave more like a car than a bicycle!