Why is the leading edge of a rear wing curved up?

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ringo
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Joined: 29 Mar 2009, 10:57

Re: Why is the leading edge of a rear wing curved up?

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PNSD wrote:
shelly wrote:ringo, the lowest pressure line is near the leading edge even for a cambered wing. Forget Venturi.
Yup.

Ringo, the method you state is not incorrect, I believe it's known as inverse design? Developed initially whilst looking at transonic aerofoils. However turbine, and compressor blades have probably found the best use of such methods.

Leading edge droop on A/C reduces the peak suction magnitude, and in doing so reduces what would be a large adverse pressure gradient.
ok here is an image, this wing is my mimicry of a williams profile so it's not a real profile:

Image

It's from early 2010, f duct days, so it has a little pressure bleading on the back of the flap, but ignore that.

whether it's not curved enough i couldn't say. But take into account the high static pressure on the leading edge.
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shelly
shelly
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Joined: 05 May 2009, 12:18

Re: Why is the leading edge of a rear wing curved up?

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Just_a_fan wrote:The Ferrari sidepod slot is a cooling outlet. It's an idea borrowed from last year's McLaren (and probably other before that).
I do not think it's a cooling outlet. It is placed before tha radiator inlet.
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raymondu999
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Joined: 04 Feb 2010, 07:31

Re: Why is the leading edge of a rear wing curved up?

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The side pod lip is a chimney outlet, copied from the mp4-25. It's cooling probably
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shelly
shelly
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Re: Why is the leading edge of a rear wing curved up?

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mcLaren introduced t on the 2, kept it on the 26. Ferrari and Force India have it this year. Form the picture I have see there is nothing under the slot for it to act as a chimney, but maybe I saw just certain angles.

That gap being an aero slot seems a logical option
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raymondu999
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Re: Why is the leading edge of a rear wing curved up?

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Where is it on the 26? I don't see it anywhere... (a similar slot)
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shelly
shelly
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Re: Why is the leading edge of a rear wing curved up?

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Sorry, I meant mp4-24 and mp4-25: the 26 does not need it because the sideod shape is different - lower leading edge, less curvature
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marekk
marekk
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Joined: 12 Feb 2011, 00:29

Re: Why is the leading edge of a rear wing curved up?

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hardingfv32 wrote:"It's common belief for unknown reasons, but it's not true. L/D for slats + main plane system is always better then for clean wing alone."

Then correct statement should have been that a clean (one element?) high lift wing comes with a high drag penalty?

Brian
Yes.
Most intuitive explanation of multielement wings superiority is that when you divide working wing area in a number of elements, these elements will have better aspect ratio (AR), lower induced drag coefficient (Cdi) and lower total induced drag: Cdi = Cl^2/(pi*AR*e). More correct and detailed explanation (proof of this theorem included) under: http://www.arvelgentry.com/amo/High-Lif ... namics.pdf

volarchico
volarchico
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Joined: 26 Feb 2010, 07:27

Re: Why is the leading edge of a rear wing curved up?

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hardingfv32 wrote:"I think some people may be greatly over-complicating a very simple cambered wing aligned to local flow..."

Roughly what would be your estimate of the alignment of local flow in the region of the rear wing?

Brian
Not the best image in the world, but at least a few streamlines show the flow angle. The air going over the wing is slightly angled down at the leading edge and then gets turned upward (thus the downforce)

Image

hardingfv32
hardingfv32
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Joined: 03 Apr 2011, 19:42

Re: Why is the leading edge of a rear wing curved up?

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Very good....

I think that you have answered the question.

Brian

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Jeffsvilleusa
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Re: Why is the leading edge of a rear wing curved up?

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volarchico wrote: Not the best image in the world, but at least a few streamlines show the flow angle. The air going over the wing is slightly angled down at the leading edge and then gets turned upward (thus the downforce)
Do you have the front view so we know the leading edge is curved?
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machin
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Joined: 25 Nov 2008, 14:45

Re: Why is the leading edge of a rear wing curved up?

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A front view of my own f1 model showing ths significant downward flow direction just in front of the rear wing... I've picked out one flow line as it goes under the wing....

Image

You get this effect whether the wing's nose is curved upward or not... curving the nose up means you avoid flow separation under the nose.... hence improved efficiency...
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Sonic59
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Re: Why is the leading edge of a rear wing curved up?

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machin wrote:A front view of my own f1 model showing ths significant downward flow direction just in front of the rear wing... I've picked out one flow line as it goes under the wing....

Image

You get this effect whether the wing's nose is curved upward or not... curving the nose up means you avoid flow separation under the nose.... hence improved efficiency...
The simpliest wing mathematical model is vortex with solid core. That explains flow behavior around your car.
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volarchico
volarchico
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Re: Why is the leading edge of a rear wing curved up?

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Jeffsvilleusa: Sorry, I found that image from a Google search; it is not mine. But I think machin's provides a much better view anyway!

Pierce: A simple mathematical model of a solid-core vortex is much more difficult to visualize for those who ask these kinds of questions than an image is! Instead of going into the theory, I was just trying to provide a simple visual answer for why with a cambered wing, the leading edge would point slightly upwards.

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MIKEY_!
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Joined: 10 Jul 2011, 03:07

Re: Why is the leading edge of a rear wing curved up?

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In my (not very well informed) opinion the high leading edge gets more air under the wing and allows the wing to have higher AoA without stalling.

Also a little like FI's under nose bulge where the curved surface is supposed to create DF.

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ringo
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Joined: 29 Mar 2009, 10:57

Re: Why is the leading edge of a rear wing curved up?

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It drops the pressure more. I mentioned venturi, but i guess it's too simple an explanation.
Look at it as a half venturi, that is all really.
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