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Old 06-13-2022, 05:48 PM   #11 (permalink)
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three feet

https://hum3d.com/3d-models/honda-dream-solar-car-1996/
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Originally Posted by freebeard View Post
Sounds excessive, a six inch tire would need a three foot tail. HVAC is an inverse case. Mair found an l/d of 1.0 gets 80% of the maximum.
Things are what they are.
This is 'wing'/ 'strut'/ 'section' stuff. Two-dimensional flow, where otherwise 'excessive' fineness ratios are king.
Solar racers will put three feet behind a one-inch bicycle tire. Cd 0.10.
Mair's metrics were only for three-dimensional flow. Peregrine falcons.

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Old 06-13-2022, 07:59 PM   #12 (permalink)
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Uh I’m just asking if the foam wedges would be decent and if anyone knows of any studies or tests that show a reduction in drag with the boat tailing behind wheels versus examples of cars using them
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Old 06-13-2022, 08:02 PM   #13 (permalink)
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Here’s an underside pic of the wheel deflectors in FRONT of the rear wheels on the Porsche taycan with a cd 0.22. Interesting how they do a boat tail into the deflectors, versus just flat deflectors like other cars. Even the Ioniq has small flat deflectors. Also since they are boat tailing in front of the wheels, why wouldn’t Porsche do the inverse behind the wheels? Even xl1 did it and Porsche wanted a low drag EV. Would be interesting to hear from the engineers
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Old 06-13-2022, 09:09 PM   #14 (permalink)
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This is what Toyota did behind the rear wheels on the 2nd gen Prius.
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Old 06-13-2022, 09:23 PM   #15 (permalink)
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Here is a drawing from 2013. For a pickup, but it could be scaled to the size of the Porsche Taycan part.



Two U-shapes fastened only on the two long edges.

[Why do all the news stories about Paul Pelosi leave out the most important detail, what model 2021 Porsche was he driving?]
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Old 06-13-2022, 10:10 PM   #16 (permalink)
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Quote:
Originally Posted by Gasoline Fumes View Post
This is what Toyota did behind the rear wheels on the 2nd gen Prius.
did they do it for the front wheels?
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Old 06-14-2022, 05:51 AM   #17 (permalink)
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Quote:
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This is what Toyota did behind the rear wheels on the 2nd gen Prius.
Nice!
I'm wondering, why didn't they do that for later gen Prius or other models?
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Old 06-14-2022, 06:38 AM   #18 (permalink)
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Quote:
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did they do it for the front wheels?
No, just the rear.
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Old 06-14-2022, 01:24 PM   #19 (permalink)
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Nice!
I'm wondering, why didn't they do that for later gen Prius or other models?
That is a good question. Heck why doesn’t Tesla do it?
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Old 06-16-2022, 10:07 AM   #20 (permalink)
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any studies

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Uh I’m just asking if the foam wedges would be decent and if anyone knows of any studies or tests that show a reduction in drag with the boat tailing behind wheels versus examples of cars using them
Sighard Hoerner's, 1951, 'Aerodynamic Drag' has hundreds of solutions with 'boat-tailing'.
So does Wunibald Kamm's/ Koenig-Fachsenfeld's research from early 1930,s FKFS, to around the time of Pearl Harbor, ending 'streamline cars.'
'The Leading Edge', by Goro Tamai.
Ignore the fact that it's a 'tire-wheel' that you're streamlining.
The 'width' of the system determines all other dimensions.
And the 'system' needs to 'enclose' the excrescence. This defines the 'width.'
The 1993 HONDA Dream solar racer is an example of an ideal wheel fairing package.

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