Why different rear wings in 2011?

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michl420
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Joined: 18 Apr 2010, 17:08
Location: Austria

Why different rear wings in 2011?

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Maybe it´s a stupid question, but i can not understand why the rear wings are so different. Up to 2009 the rear wing is so hight, it must be total seperated from the hole cars aerodynamic. There must be one perfect wing for everyone, but in 2011 we see so many differnet wings like never before (I know there is DRS but still). Can anyone explain that.
Last edited by mx_tifoso on 16 Aug 2011, 15:28, edited 1 time in total.
Reason: edited title to question form.

wesley123
204
Joined: 23 Feb 2008, 17:55

Re: different rear wings

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The rear wings are still heavily influenced by the area in front of them. Teams therefore tune different horizontal chord shapes to cope with the different flow fields.

Then you have different NACA shapes to use, every team uses a different, reasons behind this are downforce, drag and most important, flow seperation, you do not want your wing to lose downforce due to flow seperation that happens in turns for example.

Then we just have different AoA options, one team for example can run a really high nose up angle, that means that the starting edge points upwards, effectively on the first part of the wing this generates lift. I do not know the exact reason behind this, but I beleive it has to do with drag reduction.

The teams have to balance their cars out perfectly, one team having less downforce then another, and this has to be balanced out. For example McLaren runs an incredibly high AoA wing, where Red Bull runs much less AoA, just to balance everything out.

But although all these differences we actually do see an 'optimum' there are things that almost every team does. Almost every team on the grid runs a same cutout behind the wing in the end plate, it first bends down to bend upwards to full height again at the rear of the wing end plate.

Furthermore, most teams run a really short chord flap, to optimize the use of DRS, for example the Mercedes wing gains you 20kph when DRS enabled, where McLarens long chord wing gains you only 8kph.
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MIKEY_!
7
Joined: 10 Jul 2011, 03:07

Re: different rear wings

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Great explanation wesley =D> think the high front edge of the wing (was Ferrari wasn't it?)is to get more air under the wing allowing higher AoA without stalling (reminds me of venturi cars) or to reduce the pressure difference and thus less vortex.

One further question. why at tracks like Monza do most of the teams run flat wings (i know why that is) but finish them at the same height as normal(raising the front edge). Would it not make more sense to start them at the normal (minimum) height and finish lower as well. Surely the lower the wing the more efficient.

marekk
2
Joined: 12 Feb 2011, 00:29

Re: different rear wings

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Good explanation by wesley, with some small corerction:

Don't think they use NACA shapes - there's no use in aviation for such low aspect, high lift/drag wing. AFAIK they all use some variations of Liebeck airfoils (special-purpose high lift airfoil designed by R.H. Liebeck specificaly for race cars).

One thing to remeber: flows approaching rear wings leading edge are different for every car on the grid, so there's no one optimal design for all the cars.

PNSD
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Joined: 03 Apr 2006, 18:10

Re: different rear wings

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They lock mathematicians in a dark room with limited lighting to do all the integration and make their own aerofoil profiles I believe.

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flynfrog
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Joined: 23 Mar 2006, 22:31

Re: different rear wings

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The NACA airfoils were developed through experimentation not mathematics.

PNSD
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Joined: 03 Apr 2006, 18:10

Re: different rear wings

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I realize that... but there is a great deal of mathematics involved with the geometry of aerofoils. There are infact more than a few computer programs with the capability to design and alter your own aerofoil shapes via designating a desired pressure distribution. You can obtain basic aerofoil characteristics and the effects cmaber, thickness etc have on them.

I believe these programs came about for two reason's, 1) transonic aerofoil design, early NACA 64 series were not great. And 2) turbine and compressor blade design optimization.

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raymondu999
54
Joined: 04 Feb 2010, 07:31

Re: different rear wings

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I think slightly differing designs would not be too confusing as they would differ with other elements in the car, as every element in the car would probably have a downstream effect and impact on the rear wing some how.

But what I think is a bit more confusing is why teams haven't even begun to converge on a common DRS concept. For example the super short chord on the Merc, the super long one on the McL, and the RBR, which is somewhere in between, though slightly skewed to the Merc side.
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