Wind Tunnel Costs?

[JulianF]

Hi All,
Just watching the Aust GP telecast and Mike Gascoyne from Toyota was interviewed - mentioned that they have 1 Wind Tunnel running 24/7 52 weeks a year; and another being built.
I was wondering a) what are full-scale wind tunnels to build and b) what are they to run per hour? $1000 per hour? $10,000?

I suppose that this is a "how long's a piece of string?" question....

Cheers
Julian F

[greenamex2]

Originally Posted by JulianF

Hi All,
Just watching the Aust GP telecast and Mike Gascoyne from Toyota was interviewed - mentioned that they have 1 Wind Tunnel running 24/7 52 weeks a year; and another being built.
I was wondering a) what are full-scale wind tunnels to build and b) what are they to run per hour? $1000 per hour? $10,000?

I suppose that this is a "how long's a piece of string?" question....

Cheers
Julian F

I know it costs around £4-500 per hour to hire MIRA's full size wind tunnel (going to be booking a couple of hours 'soon'). Presumably they make a bit of a profit out of it.

[Al Weyman]

Blimey Dennis what the hell are you building!??

[greenamex2]

Originally Posted by Al Weyman

Blimey Dennis what the hell are you building!??

Rebuilding/redesigning my kit car (Honda NSX looking thing).

With a Nissan SR2 engine (3.0 V6 350-400BHP) and Hewland magnesium 6 speed sequential gearbox mounted mid-engined and transversely.

And genuine downforce (I hope).

And it had lots of overheating problems with a standard Vauxhall 2 litre in it.

And I haven't got any money so am having to seriously examine the benefit of every penny I spend.

It's road legal, mainly for track days but may do some sports/saloons type races when it is sorted. I'll bring it over if I every get my engine back (it's being built, slowly, by the guy who did the original LM3000/Prosport engines).

I figured it would be cheaper and easier in the long run to sort out cooling airflow in a wind tunnel than through half a dozen wasted test and track days and failed modifications, especially as I get paid by the hour. Discussions with the very helpful chaps at MIRA have proved enlightening. They are very enthusiatic and helpful, especially to club competitors.

I view the wind tunnel a bit like a rolling road session for your bodywork. It is going to be an interesting experience and I will 'publish' it on ten-tenths.

[zefarelly]

that sounds interesting, believe it or not I heard of a team putting MK1 Cortinas through a wind tunnel, they ended up rivetting a few flat plates under the car at the rear , . . . . the rear valance acts like an air scoop, which makes sense.

[greenamex2]

Originally Posted by zefarelly

that sounds interesting, believe it or not I heard of a team putting MK1 Cortinas through a wind tunnel, they ended up rivetting a few flat plates under the car at the rear , . . . . the rear valance acts like an air scoop, which makes sense.

Is that the first time a Mk1 Cortina ever went through a wind tunnel?

[Al Weyman]

Sounds interesting Dennis, make sure you keep us posted.

And Zef they may as well wind tunnel tested a house brick

[Locost47]

Hello

I've got a bit of insider information on this so i thought i'd share.

A proper full scale wind tunnel typically costs about $20-35million these days, though, just like cars, you can get them a little cheaper if you don't tick all the boxes on the options sheet.

For F1 they tend to test at between 40-60% scale most of the time since it's quicker & easier to build models than the real thing. They still manage to spend the same amount of money though.
Wind tunnels aren't particularly cheap to run - the MIRA tunnel has 1MegaWatt of fan power and that gets the electric meter spinning pretty quickly, but it's nothing compared to NASA Ames in the States which ran with over 90MegaWatts of power...

At Toyota F1 they have over 100 people working on aerodynamics in one way or another. That's going to cost a fair bit as well as all the hardware.

Who'd have thought that fresh air would be so expensive?

[avsfan733]

i'll bet 10k/hour in cost wouldn't be surprising given that they have all the boxes checked for sure...as well as having significant staff on hand constantly

[Locost47]

There's one tunnel in Europe that charges roughly £35,000 per day and has a minimum hire period of 3 days. Ouch!

On the plus side though you can test 20-50 different configurations in a day in a wind tunnel and be fairly sure of what is good/bad, whereas on track you've got to have a good driver and consistent wind/track conditions.

Something i find strange, however, is that many people go into the wind tunnel and are happy to just try stuff they've conceived themselves rather than get a professional aerodynamicist to advise them. It's kind of like going to an engine tuner's and asking him to read the paper while you have a fiddle yourself. Odd.

[Kev_205]

this is something I have pondered checking out

How would a more grass roots racer benefit the most
would you have to have different designs of parts to take along or would you spend an hour on the standard car, get advice then go away and build some bits
Then you'd have to come back?

Denis - how are you going about this?

[greenamex2]

Originally Posted by Kev_205

this is something I have pondered checking out

How would a more grass roots racer benefit the most
would you have to have different designs of parts to take along or would you spend an hour on the standard car, get advice then go away and build some bits
Then you'd have to come back?

Denis - how are you going about this?

I am not after perfection, just improvement.

I plan to take along some sheets of fibreglass, a drill, some screws and rivetts and lots of tank tape. With this I will improvise any obvious improvements and sort them out properly later.

Also, I am quite happy to take the experts on hands recommendations at face value and implement them after the session without further testing.

If it was a race car and my championship win was depending on optimum exploitation then yes I would need a van load of different parts to test in order to optimise my time.

In the end, I am only planning a couple of hours of time in the tunnel in a car that has never been near one before, almost anything I do will (hopefully!) improve it.

[Locost47]

If you're on a tight budget, normally it's best to have someone look at the car first and offer suggestions. You then build/fabricate whatever bits are required and preferably fit them before the test. It's almost always quicker to take stuff off than put it on so it's better to fit everything to the car before you go then systematically take them off, although you can still add things if the results point in a particular direction.

You can get a long way with cardboard, styrofoam and lots and lots of tank tape!

The downside of this approach is that people often see the best results at the start of the test (when all the trick bits are on the car) and then things appear to get worse through the course of the day. By the time they leave they see the worst numbers and go away thinking the whole thing was a waste of time. I know it sounds illogical but it does happen.

[greenamex2]

Probably not a bad idea locost47.

Maybe if/when I get a bit closer to booking up I'll publish some piccies on tentenths and see what people suggest.

Assuming I ever get my engine. Just how can somebody tell you "I'll phone you in a couple of weeks", for 2 3/4 years!

[topwelshman]

I'm really interested in this and have been thinking alot lately of aerodynamics, can anyone recommend anyone that is decent that I could approach to survey my car and suggest improvements?

[Locost47]

I'm new here and don't know if there are rules about traders so all i'll say is that if you follow Denis's approach you won't go far wrong.

[Kev_205]

theres a good pm system though :P

[Cameron Winton]

Many moons ago, I went for a job interview at MIRA. Place is full of people who sprint hillclimb race etc. However, the people there can only advise on tunnel conditions for whatever application you are looking at. They are not aero design experts.
A good start is Simon McBeath's book which I found good, simple & informative. From there, the best thing to do is to get friendly with someone "in the business" Anyone know Adrian Newey?

[Locost47]

Hmmm, I'm not so sure about that. I'll come clean and explain that i've been an aerodynamicist at MIRA for the last 7 years since completing my Master's degree in the subject and in that time i've done design & development work on Le Mans prototypes, GTs, saloons, single seaters, hill climbers, sprint cars and even F1 cars.

We also did the BTCC cars for Team Dynamics which comprehensively spanked the opposition last year (although the team's aero guy incorrectly took the credit).

It's true enough that many people here are racers in their spare time but we also know a thing or two about our day jobs.

[greenamex2]

Originally Posted by Locost47

Hmmm, I'm not so sure about that. I'll come clean and explain that i've been an aerodynamicist at MIRA for the last 7 years since completing my Master's degree in the subject and in that time i've done design & development work on Le Mans prototypes, GTs, saloons, single seaters, hill climbers, sprint cars and even F1 cars.

We also did the BTCC cars for Team Dynamics which comprehensively spanked the opposition last year (although the team's aero guy incorrectly took the credit).

It's true enough that many people here are racers in their spare time but we also know a thing or two about our day jobs.

As you in the know then, how about an idiots guide to a session in a wind tunnel?

[Kev_205]

Originally Posted by Locost47

Hmmm, I'm not so sure about that. I'll come clean and explain that i've been an aerodynamicist at MIRA for the last 7 years since completing my Master's degree in the subject and in that time i've done design & development work on Le Mans prototypes, GTs, saloons, single seaters, hill climbers, sprint cars and even F1 cars.

We also did the BTCC cars for Team Dynamics which comprehensively spanked the opposition last year (although the team's aero guy incorrectly took the credit).

It's true enough that many people here are racers in their spare time but we also know a thing or two about our day jobs.

you sound expensive lol

[avsfan733]

Locost may we proceed to pick you brain for several pages?

what specifically are you looking at in your thesis?

[Locost47]

We're actually less expensive than a lot of people think - about the same per hour as your average car dealer mechanic, or less.

I've got to avoid this sounding too much like an advert but i can give a generic rough guide to clubman-level aerodynamic development.

The normal order of things is to start off looking at either the actual car or photos/drawings of it and trying to identify possible problems or areas ripe for improvement. You would then make some recommendations for design changes which would require parts to be fabricated or basically any modifications that would take a while to do or require a long lead time.

Once you've got a pile of bits to try you would either book a wind tunnel test or a track test, depending on your budget, your faith in the driver and the relative reliability of track/weather conditions at that time.

For the wind tunnel approach you normally try and fit all the difficult bits in advance since removing things is usually quicker than fitting them. You then work through the various configurations you had in mind but allowing yourself to be guided by the results as they appear, so that you can focus on anything interesting or try something that you may not have thought of beforehand. Aerodynamics is a very non-linear subject and so there is always a fair amount of trial-and-error.

The same sort of methodology applies to track testing, except that it's worth doing several repeat runs to evaluate one modification (even if you've got fully instrumented suspension) because of the influence of driver/track/weather variability. This reduces the amount of configurations you can test and doesn't always provide much information about where the benefit has come from. The big plus side is that it can give you a quantifiable difference in lap time, which is obviously one of the biggest priorities overall (engine/brake cooling being the other main one).

After the tunnel/track test you would normally look through the data and see what the most important changes were and generally check through to see what affected what. The non-linearity thing means that Cause and Effect can sometimes be quite far removed in aero testing so in those cases you need to look in depth at the data to try and figure out what's going on.

This last area is where we tend to use computer simulations a lot. You can calculate what the air's doing anywhere (and everywhere) around the car and then visualise that much more easily than you can in a wind tunnel. This way you can dig deep in to the physics of what's going on and see exactly why a certain change reduced the drag or increased downforce or whatever. The big downsides of the computer simulations are the cost and requirement for CAD data of the vehicle before you start. It's not a trivial thing to work all that out (typically the computer has to solve between 30 and 100 million equations about a thousand times over...), so it takes time and fancy computers to do it. The level of information you can get out is incredible, however, and it's largely replacing model scale wind tunnel testing in the automotive industry.

Phew, that's a lot of writing. Hope it's helpful. If you've got any specific questions then just let me know.

Cheers

Rob