Developing a sports prototype

[JAG]

Reading this months Racecar Engineering I was struck how little time some front running LMP's spend in the windtunnel.

Apparently Audi and Peugeot both run programs similar to a small F1 team, but smaller teams only spend a few days in the tunnel.

Do Lola have their own wind tunnel, if so shouldn't they be way ahead of other manufactuers without access to such facilities, considering aero is so important that F1 teams often run 24/7 programs?

I also found it interesting that a current LMP produces 1500kg (3300lb) of downforce at 150mph, which is equal to a modern F1 car!

BTW, which wind tunnels are used by LMP teams, and are some better than others?

[ger80]

Embassy uses the ruag.ch windtunel.

[Mike_Wooshy]

Im pretty certain some use the one at MIRA.

[HORNDAWG]

Originally Posted by JAG

Reading this months Racecar Engineering I was struck how little time some front running LMP's spend in the windtunnel.

Apparently Audi and Peugeot both run programs similar to a small F1 team, but smaller teams only spend a few days in the tunnel.

Do Lola have their own wind tunnel, if so shouldn't they be way ahead of other manufactuers without access to such facilities, considering aero is so important that F1 teams often run 24/7 programs?

I also found it interesting that a current LMP produces 1500kg (3300lb) of downforce at 150mph, which is equal to a modern F1 car!

BTW, which wind tunnels are used by LMP teams, and are some better than others?

Yes there is a difference in wind tunnels. Some examples;

The Windshear wind tunnel, still under construction in Concord, North Carolina, will join BMW’s Sauber facility and Audi's system as the only rolling-road wind tunnels capable of testing at these speeds.

article

Lola's tunnel;

Lola Cars International 50% Scale Wind Tunnel
This project was unique in that it involved a transformation of an existing aeronautical wind tunnel into a racing wind tunnel suitable for testing 50% scale open-wheeled models. Aiolos provided, on a turnkey basis, re-erection of the former BAe 9ft x 7ft wind tunnel, plus a new test leg incorporating a 2.7m x 2.5m solid-wall test section optimized for F1 class vehicles, and the design of new fan blades to accommodate the increased performance. The facility, which became operational in 1999, includes an overhead balance and moving ground (rolling road) system.

GM's Aero Lab; link

L.P.

[Hugewally]

Wind tunnel time is very, very expensive. Then again, so are wind tunnels.

[AU N EGL]

Originally Posted by Hugewally

Wind tunnel time is very, very expensive. Then again, so are wind tunnels.

Poor mans wind tunnel. Put several drops of oil on the nose or places around the front of the car, take a lap see where the oil went.

Or put car in long narrow garage, several BIG BARN fans on one end of garage.

May not have the computers to measure, but it is a start.

[FIRE]

Dome has it's own wind tunnel.

[minimangler]

But no cars it seems, at least competitive ones...

[The Badger]

Originally Posted by FIRE

Dome has it's own wind tunnel.

So have I !!!

[skycafe]

Originally Posted by AU N EGL

Poor mans wind tunnel. Put several drops of oil on the nose or places around the front of the car, take a lap see where the oil went.

Or put car in long narrow garage, several BIG BARN fans on one end of garage.

May not have the computers to measure, but it is a start.

The Pescarolo team uses coast down testing, which lets them calculate drag. With potentiometers on the suspension, you could also roughly calculate downforce, and changes in downforce. This is nowhere near as accurate as windtunnel.

Also, CFD is very popular, and I am sure many mods are run through CFD before carbon, plastic, plaster or whatever is cut or molded, and then it is tested in tunnel to compare and corroberate the CFD model.

All the calculations and permutations, and all of that requires bank of big zoomy computers and the technicians and engineers to support and analyze it all.

I think aero is one of the downfalls of contemporary racing, but by the same token, it is utterly an utterly fascinating art.

robert

[MulsanneMike]

Originally Posted by JAG

Reading this months Racecar Engineering I was struck how little time some front running LMP's spend in the windtunnel.

Apparently Audi and Peugeot both run programs similar to a small F1 team, but smaller teams only spend a few days in the tunnel.

Do Lola have their own wind tunnel, if so shouldn't they be way ahead of other manufactuers without access to such facilities, considering aero is so important that F1 teams often run 24/7 programs?

I also found it interesting that a current LMP produces 1500kg (3300lb) of downforce at 150mph, which is equal to a modern F1 car!

BTW, which wind tunnels are used by LMP teams, and are some better than others?

The Audi and Pegueot programs are in the 50-60 day bracket possibly more.

Yes, Lola has their own tunnel, but naturally there are costs even associated with running it. And I'm not talking about overhead, I'm talking about the costs of producing models and model parts. A company like Lola has to be very budget minded, and they certainly have a budget for their LMP programs. So even though in theory they can pop in whenever they want, the accountants actually dictate that more often than not. Somwhere within Lola's site they state the B05/40 or B06/10 had something like 290 hours of wind tunnel time. Using an 8 hour day, that's about 36 days.

Imperial is still used, at least I beleive it is. Audi and Porsche use Dallara. The former Prost tunnel, (now called) ACE was used by Courage and I would guess Peugeot went there as well. MIRA is often used for full scale work. I'm unsure of their scale facilities. Creation used the Teddington tunnel (8 days). Acura uses the Auto Research Center in Indianapolis (Honda is part owner). Not sure where Zytek went but I would suspect the Teddington facility as well. Radical used the wind tunnel in Peter Elleray's brain.

Figure most commercial facilities charge at or very near $1000/hour with a minimum of 10 hours/day. So you're talking $10,000/day. Add to that salaries for model makers and design engineers, not to mention tooling to create the initial model; you're easily looking at approaching $200,000 just to get to the point to be ready to spend $10,000/day!

CFD still is of limited use in the scheme of things. Sure, if you have an F1 budget it is more useful. But its real limitation is the time it takes to run through various iterations. Figure in a average day you can do about 40 changes in the wind tunnel. And each change runs through a multi-point ride height map. So that's 40 different test items that have been run through that multi-point RH map.

Well each RH point in CFD is in itself an iteration. So if you want to CFD a development item and say just run through a couple of RH points, depending on full model or not, you're more than likely looking at a couple of days given the computing power available to most outside F1. But CFD isn't necessarily used in that sense. Its power comes from the ability to graphically generate, nearly ad nauseum I might add, flow visualization schemes. After you have a CFD run, you can pick any point in space and ask for a stream line to be generated. And that's just the tip of the iceberg. Flow visualisations, pressure distrubutions, etc., etc. Very interesting stuff. Though admittedly I still scoff at Can't Find Downforce, call me old fashioned.

3300 lbs @ 150 is approaching 6000 lbs. at 200...that's getting to be pretty decent.

[Zytek_Fan]

Originally Posted by minimangler

But no cars it seems, at least competitive ones...

Don't they work on the Honda NSX Super GT cars?

[JAG]

3300 lbs @ 150 is approaching 6000 lbs. at 200...that's getting to be pretty decent

How does that compare to a Group C/IMSA GTP car, and currently an IRL/Champ Car?

[AU N EGL]

Originally Posted by skycafe

I think aero is one of the downfalls of contemporary racing, but by the same token, it is utterly an utterly fascinating art.

robert

I agree.

[old man]

Thanks for interesting post MM.

[FIRE]

Originally Posted by Zytek_Fan

Don't they work on the Honda NSX Super GT cars?

yes

[ger80]

Originally Posted by MulsanneMike

Radical used the wind tunnel in Peter Elleray's brain.

A very cost efficent tunel

Originally Posted by MulsanneMike

CFD still is of limited use in the scheme of things.

Yes, we also have design changes after windtunel testing ...

[AU N EGL]

This may be why accura ( honda ) went with two differnt chassies. Why design themselves when chassies are aready in use, and successful, or copy the better of the two.

[MulsanneMike]

Originally Posted by JAG

How does that compare to a Group C/IMSA GTP car, and currently an IRL/Champ Car?

About 4000 lbs less than a GTP car (at their peak), about 500 lbs more than a Champ/IRL car.

[minimangler]

Originally Posted by MulsanneMike

About 4000 lbs less than a GTP car (at their peak), about 500 lbs more than a Champ/IRL car.

Should that say 400?

[ss_collins]

To add to Mikes answer

Audi - thier own (full scale)
Porsche - thier own (50%?) + university of stuttgart (Full scale)
Courage - (ACE 50%)
Lola - (Lola 50%)
Lavaggi - not sure but 1/3rd scale
Creation - Teddington
Zytek - not sure
Acura - not sure
Pesca - they dont!
Radical - MIRA 100%
Pilbeam - Don't know
WR - somewhere near paris
Lister - MIRA 100%
Dome - Dome 50%
Zulltec - ACE
Embassy - RUAG

The most advanced 50% tunnel in the world is probably Dome, followed closely by Toyota F1.

Most advance 100% will be Windshear I think.

[Aysedasi]

Originally Posted by skycafe

I think aero is one of the downfalls of contemporary racing, but by the same token, it is utterly an utterly fascinating art.

I second AU N EGL's agreement .......

[AU N EGL]

Originally Posted by ss_collins

To add to Mikes answer


Porsche - thier own (50%?) + university of stuttgart (Full scale)

Penske Motorsports has their own FULL SIZE wind tunnel for all their race car teams.

[minimangler]

Originally Posted by AU N EGL

Penske Motorsports has their own FULL SIZE wind tunnel for all their race car teams.

Does that include the Porsche?
I thought Porsche did all the Porsching?

[AU N EGL]

Originally Posted by minimangler

Does that include the Porsche?
I thought Porsche did all the Porsching?

Two NASCAR, One Busch, team, the IRL team and yes the ALMS Porsche Sypder team.

So dont you think Penske would put the spyders into their wind tunnel and test?

Penskeracing.com and take a tour of their facility.

If I had that kind of money and my own wind tunnel, my cars would be in there as much as possible, to check different wind effects and aero body parts for different tracks. and IIRC both the Spyders and the R10s have differnt body parts for diffent types of tracks and different downforces.