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Old 03-07-2020, 02:59 PM   #11 (permalink)
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I like it! Thanks, Phil. That's an easy test fix to slap together.

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Old 03-07-2020, 03:04 PM   #12 (permalink)
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I like it! Thanks, Phil. That's an easy test fix to slap together.
Darin,thanks for the mods and testing!
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Old 03-07-2020, 03:38 PM   #13 (permalink)
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That's an easy test fix to slap together.
Unless it's a fully functional difusser with fences.
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Old 03-08-2020, 10:21 AM   #14 (permalink)
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Quote:
Originally Posted by wdb View Post
Yep. Here's the same thing on a Saab 95..........
I must be dead, because I'm in slot heaven now.

Seriously, I've been looking for such examples for years ever since I did my slotted roof wing on my S-10 pickup truck.

A French aerodynamicists did a quick CFD study on it, and indeed a small amount of air was jetting though there.

One could slot the top plane as well as the side planes and still have the Kammback rear hood work, in my opinion.

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Old 03-08-2020, 02:14 PM   #15 (permalink)
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Volkswagen-GTI-W12-650-Concept (2007)
This has always (since 2007) been one of my favorite cars. It makes me wonder about grafting a Rabbit roof onto an air-cooled Beetle.
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Old 03-09-2020, 12:59 PM   #16 (permalink)
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He metro been posting about my niro having the same problem. It's factory rear wing is shaped like your kammaback. I was going to take it off to see the diff in the dirt on the rear. How was it before you put the kamaback on?
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Old 03-10-2020, 11:32 AM   #17 (permalink)
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Originally Posted by MetroMPG View Post
That said... I'm thinking of testing a quick 'n' dirty box cavity. I wonder if that will keep it cleaner.
Please do. I have an upcoming road trip in the Golf and I am considering trying some mods before I go. Would your box cavity match up with the bottom of the back hatch?
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The power needed to push an object through a fluid increases as the cube of the velocity. Mechanical friction increases as the square, so increasing speed requires progressively more power.
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Old 03-11-2020, 10:52 AM   #18 (permalink)
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slots

Quote:
Originally Posted by kach22i View Post
I must be dead, because I'm in slot heaven now.

Seriously, I've been looking for such examples for years ever since I did my slotted roof wing on my S-10 pickup truck.

A French aerodynamicists did a quick CFD study on it, and indeed a small amount of air was jetting though there.

One could slot the top plane as well as the side planes and still have the Kammback rear hood work, in my opinion.

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Volkswagen-GTI-W12-650-Concept (2007)
Net Cars Show: 2007 Volkswagen GTI W12-650 Concept
I went back and looked.Hucho is absolutely adamant about non-aspirated structures on road vehicles.Slots,slats,and spoilers can perform on an aircraft in 2-D flow,but never on an automobile in 3-D flow.Any boat tail or box-cavity must be airtight in order to function.Texas Tech's cab-wings were non-aspirated.
A permutation that is permissible is,to use a slot to pressurize an air-tight,fabric boat-tail envelope as I,and Bruce Ruefer (SP?) did.
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Old 03-11-2020, 11:08 AM   #19 (permalink)
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Quote:
Originally Posted by aerohead View Post
I went back and looked.Hucho is absolutely adamant about non-aspirated structures on road vehicles.Slots,slats,and spoilers can perform on an aircraft in 2-D flow,but never on an automobile in 3-D flow.Any boat tail or box-cavity must be airtight in order to function.Texas Tech's cab-wings were non-aspirated.
A permutation that is permissible is,to use a slot to pressurize an air-tight,fabric boat-tail envelope as I,and Bruce Ruefer (SP?) did.
I think a lot of study on slotted flaps (aircraft) and slotted wings (F1/Indy) race cars has been done after the mid-1980's.

However, I agree that the real world is 3D and very messy.

To clarify, the gentleman who so graciously did my CFD made no claims about the roof wing slot.

When I pushed him it was a concession of sorts, and visible in the graphic.

Just debatable about it's affect and meaning.

I wanted it to mean the slot introduced a high velocity thereby lower pressure area under the wing (more so than it would have with sealed leading edge), and that this promoted the air flowing over the top of the cab to collapse on top of it, which lead to the air mass encountering the truck bed cover slightly sooner, and making my rear Gurney flap all the more effective in producing down-force.

My slot was very small, not sure it had any affect larger than life as I would fantasize about on cold rainy days.

In this situation all we are trying to do is keep a rear window a bit cleaner.

To be honest, even with it slotted to the hilt, it's always going to be dirty - in my opinion.
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Old 03-11-2020, 01:07 PM   #20 (permalink)
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Quote:
Originally Posted by aerohead
Hucho is absolutely adamant about non-aspirated structures on road vehicles.Slots,slats,and spoilers can perform on an aircraft in 2-D flow,but never on an automobile in 3-D flow.

https://d2d0b2rxqzh1q5.cloudfront.ne...cc66dcc08a.jpg

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