2006 LMP1/2005(6)Hybrid: The difference?

[Bentley03]

With Le Mans 2005 done and dusted and Le Mans 2006 already being discussed and anticipated I'd be interested to know whether or not the regulations (in theory) will give the 2005/2006 hybrids a performance advantage over the all new full spec LMP1's, and the differences between them.

Fuel tank capacities?
Weight penalties for hybrids?
Overall dimensions?
Aero advantages for hybrids?
And a host of other criteria that could favour one over the other.

It also seems likely we will see at least a couple of closed top LMP1's next year. Will these cars still be disadvantaged in terms of tyre width and/or any other regulation specific to their type?

My appreciation to anyone who has evaluated and compared the new regulations for the 2006 LMP1's and takes the time to comment. It will be interesting to see how theory relates to reality when the full spec LMP1's enter the arena.

[paul-collins]

As far as I know, the difference is down to this:

New cars have new tubs designed to properly integrate into the new bottom aero regime. Hybrids have the old design which is likely flat. Hybrids may have an aero advantage by generating some ground effects downforce here. I'm not sure if the amount is much.

New cars have the full double rollover structure whereas the hybrids have only been required to include the "secondary" double rollover structure for aero purposes, not safety. So again there's more aero impact to the new cars as the second rollbar (or the full width one) will be in the air where the hybrid only has the hump.

I don't remember any penalties assigned to hybrids, only that they're explicitly disallowed after next year.

[MulsanneMike]

Originally Posted by paul-collins

As far as I know, the difference is down to this:

New cars have new tubs designed to properly integrate into the new bottom aero regime. Hybrids have the old design which is likely flat. Hybrids may have an aero advantage by generating some ground effects downforce here. I'm not sure if the amount is much.

I wouldn't think that was a big issue as the regs. mandate a 800 mm x 900 mm wide flat reference area anyway (3.5.1) and the tub minimum width is also 900 mm (16.2.1 b/). And the hybrids must (and are) running the exact same underfloor regulations, chamfer and all. So as for underbody downforce, it is nearly a wash LMP900 hybrid to LMP1. Certainly the hybrid wouldn't have any inherent advantage, in fact it may very well be the other way around.

The big advantage a LMP1 design will have is that it is not a compromise design, it is a clean sheet as it were. Hybrids such as the Pescarolo Courage were originally designed to the LMP900 regulations. A small example can be seen on the Pesca car in that the rear suspension lower A-arm is running in the diffuser exit. While certainly a small issue in the whole scheme, you would think there would be some advantage underbody aero-wise to lifting that lower A-arm up just slightly and containing it within the car. Pesca wanted to avoid a rear suspension geometry redesign (and subsequent set up loss) I'm sure and therefore kept it the way it was as run on the C60 LMP900.

[Pete Fenelon]

Peter Elleray (Bentley designer) on the aero regs: http://www.mulsannescorner.com/lmpelleray.html

Kieron Salter (Reynard/DBA/Zytek designer) on the 2004-2006 transitional regs:
http://www.mulsannescorner.com/kieronsalterlmp12.html

If you're sensing a theme here - Mike at mulsannescorner collects some of the best sports car techie info out there - the site is a masterclass in prototype technology.

[JAG]

'It also seems likely we will see at least a couple of closed top LMP1's next year. Will these cars still be disadvantaged in terms of tyre width and/or any other regulation specific to their type?'

Closed LMP1 AND LMP2s are the same spec as their open cousins.

Incidentaly Lola say they could produce a closed version of their new LMP1 if a customer wants it.

Despite hybrids being theoretically better, aero wise, than a full LMP1, tech/aero advancements over the last couple of years should give the full LMP1's a performance advantage.

Just look at the Lola P2 versus the hybrid Courage C65.

[Bentley03]

Originally Posted by JAG

.....Despite hybrids being theoretically better, aero wise, than a full LMP1, tech/aero advancements over the last couple of years should give the full LMP1's a performance advantage.

Just look at the Lola P2 versus the hybrid Courage C65.

Possibly not your best argument after the no.37 PB Courage took pole at both Le Mans and Monza.......

But I take your point......