A question on windtunnel models.

[Conceptual]

I have read in several places that the teams build 60% scale models for wind tunnel testing. I have also seen the pics of the Toyota wind tunel model that was made from carbon fibre. The tyres looked like they were made from skateboard wheel material (very stiff polyurethane), but the rest of the car was unpainted.

My question is are the 60% models absolutely complete, or are they just body panels mounted on some skeleton structure.

I would think that a 60% F1 chassis with some sort of motor (954RR twin turbo comes to mind) would be nothing short of amazing.

Are these just mini F1 cars, or simply aero contraptions with no internals?




Thanks for your answers!

Chris

[Jersey Tom]

There are no internals.

[Conceptual]

There are no internals.

So it's a self supporting shell? Or is it actually a monocoque, and can have these things added to it.

Saying there are no internals is kind of vague, can you be more specific of what actually IS under the skin?

Chris

[Shi Ruan]

Total assumption here, but I'd guess they have some facsimile of the cooling and exhaust system so as to take that airflow into account. But I'm fairly certain they wouldn't have any internal mechanisms beyond perhaps some form of data gathering equipment.

[Ciro Pabón]

I read sometime ago that the parts are self-sustaining, made by stereolitography, kind of an ink jet printer that uses resin instead of ink.

They do it that way to assure a continuous flow of parts that are tested one after the other, because operating the tunnel costs a kidney and they are used in continuous shifts, 24 hours a day.

So, that discard building internals with tiny 60% engines, tiny 60% chassises or tiny 60% drivers (hey, they could use Ecclestone for that, or Graham Rahal, the american driver...). However, if they were makinkg them in that way, I'm sure more than one karter would buy them.

[Conceptual]

I read sometime ago that the parts are self-sustaining, made by stereolitography, kind of an ink jet printer that uses resin instead of ink.

They do it that way to assure a continuous flow of parts that are tested one after the other, because operating the tunnel costs a kidney and they are used in continuous shifts, 24 hours a day.

I've seen the resin building quick-prototyping machines in use, and I think they are amazing. However, I don't think that they can produce the cleanliness that is necessary for aero testing. IE: The surface is rough.

I am still very interested in knowing what is INSIDE one of these models. Does anyone have some more to add to this?

Chris

[Ciro Pabón]

Well, sorry for posting so much and answering so little (I'm building an installer, and every time I run the compiler I have to wait like 30 minutes, so I've posted like 10 times today ).

Actually, it's not that simple. They name of the technique is "Laser sintering". The machine (kind of a rolling printer, like in litography) sprays a resin powder that is sintered or fused by a laser with pinpoint accuracy in a special chamber filled with inert gas. The machine is directly hooked to the CAD computer. I imagine it's not rough, because that's what they use. What holds everything together, I don't know.

Check here:

http://www.windform.it/sito/en/2005-12- ... emand.html

[Jersey Tom]

A typical resin SLS machine will have a "stepped" rough outside surface, yes. Generally smallest feature size is ~0.025"

Rapid protyping these type parts (or carbon composites.. or metals) uses a slightly different process. You can get better dimensional accuracy using different machines, and you can always hand finish rough spots.

[nas]

Hi Chris, I just spotted the thread started by you and saw that you didn’t get a response on the question what’s inside the wind tunnel models - there is a load bearing structure in the form of a spine (usually made from aluminium, it is sort of a back-bone chassis) which carries the outer shell and which is attached to the big aerofoil shaped strut seen on the pictures – this strut picks the model in the middle. There are also two methods of testing – “wheels on the model” and “wheels off the model” – in the former the wheels are attached to the model (vie the model uprights), while in the latter the wheels are carried by separate struts as seen on your pictures. Some F1 teams favour the first method, some the second.

[bazanaius]

NB Ciro

http://en.wikipedia.org/wiki/Sintering

[xpensive]

When I didn't want to open a new thread just for this booring ---, I elected to pick up on a related one.

Visiting the Windshear website, I couldn't help but be taken aback by the shear numbers of that contraption;

- A 6.71 m fan blowing 1345 m^3/sec through a 3.0 by 5.5 m nozzle up to 80 m/s (290 km/h)!
- A 4 MW motor, which will send an electricity bill of 96 MWh (some 10 kEUR) per day if used at full song around the clock.

Knowing just how much time the big-dogs spends in the windtunnel, good mother of Jesus what a waste of energy!

When a 60% model would be happy with a nozzle one third of the above area and probably half the air-speed,
power should be a fraction, why I understand the incentives behind the 2009/10 regulations on windtunnels.

[WhiteBlue]

Very few operations have a 100% scale rolling road tunnel. I believe that Sauber was one of the first in F1 (15 m² ).

http://www.f1technical.net/articles/47

Merc have the old Honda tunnel ( 5.2 m² ) and are now actively seeking business for it in other sports like cycling.

http://windtunnel.brawngp.com/windtunnel.asp

They probably use the new 100% tunnel for F1

http://www.f1technical.net/features/4612

McLaren do not have a full scale rolling road tunnel (only 50%) but I suspect Toyota is closer to full size.

Ferrari have a 65% scale tunnel with 12 m² working cross section.

http://www.thescuderia.net/windtunnel.shtml

So the Charlotte facility is pretty much unique for F1 teams if we disregard Sauber.

[scarbs]

A c2004 windtunnel model spine, machined from aluminium. you are looking from the rear, with the car pointing forwards.
Everything else mounts to this spine, bodywork, suspension etc.

[xpensive]

What am I looking at here scarbs?

[PNSD]

Traced back to the site..

http://www.crowthornenc.co.uk/5429.html

Windtunnel model spine !