GT wing effectiveness...anyone experimented?
07-07-2008, 02:02 AM
#61
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well i've decided not to drill into my new trunk...i'll just keep my old OEM spare and run my wing on that when i take it to the track. I'll do some experimenting myself on my next track day 
07-07-2008, 02:27 AM
#63
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Originally Posted by mikegarrison,Jul 5 2008, 12:33 AM
The issue is that the underside of the wing (or top side on an airplane -- lets call it the "suction side") has what is known as an "adverse pressure gradient". What that means is that only the momentum of the air going past the wing is keeping it attached to the curvature. As it slows down it loses energy. As it loses energy, it eventually peels away from the wing surface. We call that "separating". On the other side of the wing ("pressure side"), there is no adverse pressure gradient, and you don't need to worry about separation.
So the suction side is the most critical to get just right, or else your wing is going to not perform well. But it would be incorrect to think that means it "does all the work". Kind of like your driveshaft. It it breaks, your car is going nowhere. But that doesn't mean it is your driveshaft that does all the work in making your car go forward.
So the suction side is the most critical to get just right, or else your wing is going to not perform well. But it would be incorrect to think that means it "does all the work". Kind of like your driveshaft. It it breaks, your car is going nowhere. But that doesn't mean it is your driveshaft that does all the work in making your car go forward.
it's an airplane wing turned upside down.
should've drawn the wing better
Point is, overpass pressure > underneath pressure
=> downforce (technically speaking.. a suction pulling down)
note: Vacuum happens when the air wants to rush in into the space that it once filled after the car has traveled across & disturbed its medium. Not a worry if you have a car drafting behind you (well.. in formula racing atleast). Broadly speaking, vacuum will slow your car down. Not a really good explanation but: it sort of "pulls" your car back. You can see this in hatchbacks.
higher pressure above (i guess u can say slower / more dense air / more turbulant air)
lower pressure underneath (less concentration of air / quicker movement of air through the medium / vacuum style)
'JackOlsen's misconception (before he experimented) is somewhat correct if you take a look @ the nascar and some dakar / dune buggy race cars.
tracking with your top down will slow you down and give you lift.
07-08-2008, 12:18 AM
#65
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Early in the process, I also videotaped wool tufts to get an idea of airflow and adhesion. I got carried away, and tried some downright silly ideas for keeping the front down.
The downright silly:
I've played a little with side skirts and underbody treatments.
Some of it worked, a little. But with street springs, it also made the car more unpredictable:
I tried a bunch of different splitter designs.
The latest utilizes a verticle curtain in front, with the splitter moved further forward.
My most recent front end:
I also used ABS to flatten out the underbelly surface of the car.
Aero is a factor at a track like Willow Springs in California. At most tracks, though, production cars are going to see a very small (like in the 1/4 to 1/2 second per lap, tops) benefit.
More can be done. But you've got to be willing to sacrifice to get it -- think 2000# springs...
The downright silly:
I've played a little with side skirts and underbody treatments.
Some of it worked, a little. But with street springs, it also made the car more unpredictable:
I tried a bunch of different splitter designs.
The latest utilizes a verticle curtain in front, with the splitter moved further forward.
My most recent front end:
I also used ABS to flatten out the underbelly surface of the car.
Aero is a factor at a track like Willow Springs in California. At most tracks, though, production cars are going to see a very small (like in the 1/4 to 1/2 second per lap, tops) benefit.
More can be done. But you've got to be willing to sacrifice to get it -- think 2000# springs...
07-08-2008, 12:28 AM
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Most recently, I tried slightly different uprights and experimented a little with winglets in place of the normal type of (rules-dictated) endcaps.
As you can see, I'll try anything once.
The inspiration:
Oh, one last cheap option for a DIY wing: the services that cut foam wings for RC aircraft. You can get a very strong and light piece made with a tube (or two) cut inside it for aluminum reinforcement pipe. You can put a skin on the foam in a handful of ways -- the simplest is a kind of plastic tape. I tried contacting an outfit that cuts the wings, and didn't get a response -- so I went with the aluminum. But here's a link and a picture:
http://www.flyingfoam.com/CustomMain.html
I think you could get a complete and very accurate wing for less than $100 this way. But like I said, I didn't hear back from them when I emailed.
As you can see, I'll try anything once.
The inspiration:
Oh, one last cheap option for a DIY wing: the services that cut foam wings for RC aircraft. You can get a very strong and light piece made with a tube (or two) cut inside it for aluminum reinforcement pipe. You can put a skin on the foam in a handful of ways -- the simplest is a kind of plastic tape. I tried contacting an outfit that cuts the wings, and didn't get a response -- so I went with the aluminum. But here's a link and a picture:
http://www.flyingfoam.com/CustomMain.html
I think you could get a complete and very accurate wing for less than $100 this way. But like I said, I didn't hear back from them when I emailed.
07-08-2008, 12:32 AM
#67
Hey Jack, Excellent work there.
I am curious to ask. did you try a comparo between a splitter vs a lip like the APR lip?
I like the splitter but am worried that it will not provide enough downforce to keep the nose down.
btw, the placement of your splitter seems a bit high?
I am curious to ask. did you try a comparo between a splitter vs a lip like the APR lip?
I like the splitter but am worried that it will not provide enough downforce to keep the nose down.
btw, the placement of your splitter seems a bit high?
07-08-2008, 01:45 PM
#69
Originally Posted by vjarnot,Jul 8 2008, 03:11 AM
I recently picked up a refrigerator compressor, and am seriously thinking about trying my hands at vacuum bagging a foam core...
07-08-2008, 01:58 PM
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Jack,
Love the little story and timeline you made out of the progress of your car
Did you run into that little pillar that looks like Big Willow? That guy must have been freaked out!
Love the little story and timeline you made out of the progress of your car
Did you run into that little pillar that looks like Big Willow? That guy must have been freaked out!