A question on windtunnel models.

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Post Tue Dec 29, 2009 2:53 pm

An even better image

flickr.com/photos/vulcan/113608527/
scarbs
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Post Tue Dec 29, 2009 3:00 pm

Aha, I think I get it now, the above image is what you typically begin with for a 60% model, such as MG's Lotus thing we have seen, as opposed to a 100% situation, where you can use the actual car, is that correct?
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xpensive
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Post Tue Dec 29, 2009 3:03 pm

xpensive wrote:Aha, I think I get it now, the above image is what you typically begin with for a 60% model, such as MG's Lotus thing we have seen, as opposed to a 100% situation, where you can use the actual car, is that correct?

exactly...
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Post Tue Dec 29, 2009 3:26 pm

So anyway scarbs, between thumb and pointer, how many hours would a top F1-team spend in a 100% tunnel per season if unlimited access was given, 24/7?

How many man-hours at a 60% as we speak?
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xpensive
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Post Tue Dec 29, 2009 3:42 pm

Williams is believed to own their old 50% tunnel and a new one which is probably close to 100%. They used to run at least one tunnel 24/7 according to Tomlinson, their aero boss.

http://www.williamsf1.com/feature/view/532
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Post Tue Dec 29, 2009 3:56 pm

xpensive wrote: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.


Windshear does have a nice facility, I've been down there.

There are times when a 100% scale tunnel is cheaper than a 60% one.. eg when you already have a full racecar (NASCAR, IRL, Star Mazda...) and don't want to build a 60% model.
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Post Tue Dec 29, 2009 4:11 pm

Currently teams are only allowed to run models up to 60% as well as the aforementioned limited number of full-scale tests. Now I recall they are restricted to a single 8 hour shift per day. Before the 2009 limits, teams would test three shifts a day everyday at each wind tunnel. As close to a 24/7/365 operation as finances and tunnel maintenance would allow. Of course not every team had those levels of resources, and by losing the more expensive night shift, many simply ran a double shift covering 16 hours of tunnel time each day. Sam Michael told me they work in two week cycles with a few days of full scale testing included in that cycle for correlation purposes. So I guess that allows around 50-70 days of full scale testing, although I doubt they would run the full scale option in-between each cycle.
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Post Tue Dec 29, 2009 4:33 pm

Reading the rules, I'm not certain if this means that you can do as much 100% running as you like between the last race of 2009 and January 1st, 2010?

iii) six one day aerodynamic tests carried out on FIA approved straight line or constant radius sites between 1 January 2010 and the end of the last Event of the Championship. Any of these days may be substituted for four hours of wind-on full scale wind tunnel testing to be carried out in a single twenty four hour period.

If that's the case, I guess everybody is scrambling to get as much 100% running possible before 00.00 Friday morning?
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xpensive
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Post Wed Dec 30, 2009 10:34 am

OK, let me re-phrase the question; Are the teams allowed to do any 100% windtunnel testing whatsoever,
between the last race of 2009 and January 1st, 2010?
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xpensive
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Post Thu Jan 07, 2010 10:27 am

I heard that the 100% wind tunnels are more used for studying the effect of cars following each other rather than just sticking a complete car into the tunnel.
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Post Thu Jan 07, 2010 11:13 am

xpensive wrote:OK, let me re-phrase the question; Are the teams allowed to do any 100% windtunnel testing whatsoever,
between the last race of 2009 and January 1st, 2010?


I understand that rule as saying 100% testing may only be carried out between 1 Jan and the last event. Hence no 100% testing after the last event to 31st Dec.

Others have commented on duration restriction for 60% models. This isn't in the FIA rules, but Ross Brawn made some comments about it at the British GP press conference on 19th June 09. He talks of "60 hours" total. I wonder if that is per season? Compares to 24 hours at 100% scale.

Ross Brawn wrote:You’ve got Toyota with two wind tunnels running flat out 24 hours a day, seven days a week and they made a concession to reduce the hours they run in the wind tunnel to sixty hours total, that’s sixty hours total for all their wind tunnels in order to compromise with the smaller teams who didn’t have the budget to run two wind tunnels full time, 24 hours, seven days a week. So that’s one example where compromise has been found, between the FOTA teams, where the large groups have accepted compromise in the interest of the smaller groups. Now, as a smaller group, I can’t ask Toyota to come down completely to my level but I know that there’s a smaller difference there between what we can afford to do in the wind tunnel and what they can afford to do. So there has been incredible movement within FOTA. I mentioned the cost of engines; these are all FOTA initiatives, they’re all things that the teams themselves have worked together to…. The testing agreement is a totally voluntary agreement between the teams. It wasn’t an initiative started by the FIA, it was an initiative started by the teams. We all agreed to it and to my knowledge nobody has ever breached the testing agreement, and that’s purely voluntary.

http://www.fia.com/en-GB/mediacentre/pr ... _gbr2.aspx


I also remember talk of limiting the CFD capability by measuring terraflops, but I can't find a ref to that at the moment.
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Post Thu Jan 07, 2010 9:22 pm

The FOTA limit works like this. CFD usage is limited by Teraflops per week. Windtunnel usage is limited by 'wind-on' hours per week. the '60 hours' number throw out in a previous post refers to 60 hours per week (wind-on time). Nothing limits model-change time, maintanance time, etc in the tunnel. therefore, to say that there is now only a single 8-hour shift every day in the tunnel is not true.
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Post Sun Jan 10, 2010 4:18 pm

Pretty much like Nas said,the sledge (ali backbone) is placed inside a replica chassis you will have a dummy engine,gearbox and exhausts.There is nearly as much aero work done under the body as there is on the outside with wings, you have rad inlet ducts and the rads themselves with "fake" cores so the air can pass through as in a real car and any duct or item on the back side of rad that the airflow might be affected by.Lots of bits like loom,ecu,s ,control boxes arent put on a model its still fairly impressive under a wind tunnel model
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