Dallara Wing made in Culver City over $1000 saved

Wil is onto something but...

I don't think George is racing this Martini X though...

Here is a shot of Graversen with the same angle wing Wil is talking about...

Although I have seen many more photos of him running the split wing below.

graversen222mc.jpg
george.jpg


graversen178zw-1.jpg
 
Graverson?

I've neveer seen that orange widebody X before that's gotta be the sickest X1/9 IVE EVER SEEN!!! Does anybody have the info on this thing/? Is that a custom widebody? What size are those wheels??
 
Explanation on Dallara Wing

I understand you are right about some basic aerodynamic principles, but let me explain how this one works. The wing on the Dallara was not intended to put any pressure in the rear or to create any lift or drag effect.
It creates a turbulence (on purpose) in the rear of the car that vacuums the turbulence caused by the rear window creating a laminar flow so the boundary layer of air remains within the shape of the car for longer period. Lesser turbulence means less drag.
Anyways, at supersonic speeds I have nothing to worry about.:grin:
aleron1.jpg

dallaraaerodcopy.jpg

x19aerod.jpg
 
Dallara wing explained

I understand you are right about some basic aerodynamic principles, but let me explain how this one works. The wing on the Dallara was not intended to put any pressure in the rear or to create any lift or drag effect.
It creates a turbulence (on purpose) in the rear of the car that vacuums the turbulence caused by the rear window creating a laminar flow so the boundary layer of air remains within the shape of the car for longer period. Lesser turbulence means less drag.
Anyways, at supersonic speeds I have nothing to worry about.
aleron1.jpg

dallaraaerodcopy.jpg

x19aerod.jpg
 
cozzoi said:
dallaraaerodcopy.jpg

x19aerod.jpg
Click to expand...

I don't think air moves like that, yes there is a pressure zone there. I just don't think it works like your depicting.

f150_wind_tunnel.jpg


I would expect our cars to act much in the same manner as a truck bed, with a bed cover on it. As seen above the air still dips as it comes off the roof, if the truck had a wing the same height as the roof it would be functional, but if the wing was only slightly higher then the bed it would not be as function if at all.

Basically, your right that the wing is leveling out the air stream coming from the roof line, but its placement there is because thats where you can put a wing and generate the most downforce, not just to level the air. If you only want to reduce drag, you want a smaller rear footprint not a larger one.
 
newer models like the one you are showing are a totally different story. smooth curvatures, shaved moldings, longer roofs, longer bed. (if you observe, the vacuum created by the tailgate sucks the upper layer and get it closer to the bed, imagine what could happen if the bed is half as long = a huge turbulence is created that drags the vehicle, like in the x1/9)
I tried to give you a general idea on how it works and may not represent exactly how smoke streamlines look like.
I study aerodynamics for 2 years as part of my Industrial Design career and saw how a small detail can alter the whole stream pattern.
Help me find some similar pictures from the 70's or 80's compare and get to a conclusion.
Love the discussion and appreciate your interest in the subject.:worship:
 
That CFD study was completed several years ago by me. It is actually just a 2D study to see the flow through my oil cooler. I have a vent under the license plate with the plate space away from the body. The inlet on the bottom is not real - only an inlet to allow the air to flow in a 2D model. The flow over the roof etc however should be accurate at the speed I ran the model which if I remember correctly was around 80Mph. If you look closely you can see the Corsa profile minus the rear wing (which does nothing functional) on the model.
 
mike3487 said:
Was sent this a while back when trying to determine weather or not a duckbill does anything

cfxOutput-1.jpg
Click to expand...

I knew i had seen this before, but had not remembered it. This is exactly why the shape of that wing IS important. Notice the air is acting almost identically to the truck air flow as it comes off the roof.

I would remove the skin and reshape the core to match one of these shapes. I don't see the point of putting a wing on a car without even having it the right shape :2c:

Here are some wing designs that would work.
NACA230121153297622.jpg

Naca1153289665.jpg
 
No problem Mike. I don't really care about the credit. That image has been floating around for awhile and never seems to have the same story behind it. I just thought I'd explain what the study was actually looking at. This discussion has motivated me to play a little bit. The attached image shows a wing added (oil cooler detail removed). I just eye-balled a wing. The model is at 80Mph. The wing (as I have it) does create down force however not much. In the model it generates about 4-5 psi that is acting on the upper surface of the wing. Also interesting (but not surprising) is the low pressure area behind the rear window is creating lift. Again not much. I would imagine that Dallara added the wing to both create some down force as well as smooth the flow reducing the turbulence at the rear of the car.

x1980mphwithwing.jpg
 
Brad Garska said:
x1980mphwithwing.jpg
Click to expand...

Can you model something like this one? I believe it may be more accurate

I used the window profile, rather then the actual visual profile of the x, the window drops more vertically. I also added an engine compartment, and places for air to exit it and go up into the negative pressure zone. This could show a different air flow and maybe more accurate?
x19_2.jpg
 
OK here it is with a bit more refinement. As before the model was run at 80Mph. I included a few different results. So it can be visualized better. It's difficult to show all the details I can see when viewing the model real time. I didn't include the vent through the rear trunk for the oil cooler as it appeared in your sketch as it is not really part of this study. The wing is generating down force with about *12.5 psi due to it's more aggressive profile, acting on the upper surface.
* The values are only for reference as the model is not qualified in anyway. The flow characteristics however are representative of what can be expected from this profile.

X19wingstreamline.jpg


X19wingvectors.jpg


X19airflowwingpressuremap.jpg
 
Brad Garska said:
OK here it is with a bit more refinement. As before the model was run at 80Mph. I included a few different results. So it can be visualized better. It's difficult to show all the details I can see when viewing the model real time. I didn't include the vent through the rear trunk for the oil cooler as it appeared in your sketch as it is not really part of this study. The wing is generating down force with about *12.5 psi due to it's more aggressive profile, acting on the upper surface.
* The values are only for reference as the model is not qualified in anyway. The flow characteristics however are representative of what can be expected from this profile.
Click to expand...


What program did you use to run the simulation
 
Those look to be the most accurate models yet. Can we see one without the wing so we can get a better idea of what stock would look like?
 
X19airflowvectorsnowing.jpg

X19wingvectors.jpg


I think these two show best why the wings are being placed so high!

I have one little mod idea I want to test out, its a common piece found on the mk1 MR2. A rear visor to direct the wind off the roof down. As seen below
2939536716_ff526bcdb2_o.jpg


I am thinking of makeing some for the x. I would like to get an idea to see if they are indeed worth it.
 
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