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Old 11-10-2014, 03:01 AM   #561
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Gee em- the effects of the flow separation over the rear window are not illustrated well by that type of test/visual..

On a different note, Am I the only one who thinks that something about that wind tunnel airstream pic doesn't look right?
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Old 11-10-2014, 03:58 AM   #562
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That is not a legit photo!
It has been photoshopped.


You can clearly see the two lowest smoke streams hit the front of the car but go nowhere. (the lowest actually should appear out the bottom of the rear of the car)
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Old 11-10-2014, 04:36 AM   #563
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Wow, it's not even well done. You can see the car cut out lines. That lower stream just vanishes.
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Old 11-10-2014, 06:31 AM   #564
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Yeah, there was some discussion about that in the source thread (at least, the thread I found) - I was trying to be tactful lol.

I am not (yet) ditching the tuft testing. I don't think it will come up to your standard David, but I will see how it pans out.
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Old 11-10-2014, 07:04 AM   #565
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Photoshopper didn't get the shadows right and it's a rough cut around the tires.
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Old 11-10-2014, 02:50 PM   #566
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Dammit. I knew something about that image didn't look right. I started to put a disclaimer about unknown source, but then I saw that it was from dannysteynracing.com and decided to trust it.
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Old 11-10-2014, 03:05 PM   #567
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Old 11-11-2014, 12:28 AM   #568
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Henry @ KazeSpec Engineering has done some tuft tests of the airflow over the hardtop w/ and w/o a hardtop spoiler, if that helps.
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Old 11-11-2014, 01:10 AM   #569
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Yeah I was looking at it via my phone when I posted that it didn't look right. Too small to notice the photochop evidence, but even at 2"x4" or whatever my iphone screen is, the air streams didn't look right.

-Ryan
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Old 11-11-2014, 01:11 AM   #570
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On the weekend we did some testing with Lightyear aero paint.



image sharing sites
Interesting results. Some predictable, others I was surprised.

It shows no airflow going over the top of the side skirts.

Next time we will get a washer bottle, and run hoses to different parts of the car. Turn the pump on for a few seconds. Then study the lines when you get back to the pits.
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Old 11-11-2014, 01:17 AM   #571
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Old 11-11-2014, 09:56 AM   #572
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Quote:
Originally Posted by motormechanic View Post
Henry @ KazeSpec Engineering has done some tuft tests of the airflow over the hardtop w/ and w/o a hardtop spoiler, if that helps.
Link? Can't seem to find it.
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Old 11-11-2014, 07:18 PM   #573
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Good job Lightyear as usually, good job. I am hoping to run some tests once my engine swap is complete. I've noticed the condensation in the morning going up the hood in the low pressure area.
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Old 11-12-2014, 03:05 AM   #574
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I'd be interested in that link too. Although it doesn't sound like what I am looking for, I'd still like to check it out.
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Old 11-12-2014, 05:24 PM   #575
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I am working through reading this entire thread. In the meantime, does anyone know the function of holes in endurance car mirrors? Also what is the theory behind "goose-neck" wings.
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Old 11-12-2014, 06:21 PM   #576
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Quote:
Originally Posted by smite View Post
I am working through reading this entire thread. In the meantime, does anyone know the function of holes in endurance car mirrors? Also what is the theory behind "goose-neck" wings.
Gooseneck wing mounts are intended to leave the airflow under the wing as undisturbed as possible. Faster air flow =lower pressure, lower pressure on the underside of the wing = more downforce. In reality the main benefit is that you can achieve the same down force with less drag by running less AOA on the wing
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Old 11-12-2014, 11:13 PM   #577
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It's on facebook, but here's a pic of the stock hardtop, and with a spoiler installed.




Action shot:


link:
https://www.facebook.com/KazeSpecEng...type=3&theater
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Old 11-20-2014, 07:31 PM   #578
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So I came across this photo after a loooong time looking - T16 undercarriage.

Regarding the venturi tunnel setup - assuming I could fit either a diffuser of a given length (flat or slightly curved with vertical strakes) or had the option of building up a teardrop shaped center section to create a short pair of tunnels with the same overall length at the diffuser option, would there be any benefit to running tunnel setup (reference my super awesome tunnel sketch).



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Old 11-21-2014, 03:09 AM   #579
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If you are limiting the size of the tunnels to the length of a diffuser, the tunnels are essentially just 2 converging smaller diffuser sections. I would see no benefit to that at all.
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Old 11-21-2014, 08:20 AM   #580
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Quote:
Originally Posted by motormechanic View Post
If you are limiting the size of the tunnels to the length of a diffuser, the tunnels are essentially just 2 converging smaller diffuser sections. I would see no benefit to that at all.
So we're on the same page - now, what if the tunnels extend further forward into the undercarriage than the diffuser and received cleaner air? Is there a tradeoff in clean air of a reduced volume vs. turbulent air over a larger cross section (lets assume transmission, driveshaft tunnel are the primary culprits).
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