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Old 04-05-2013, 11:36 AM   #21 (permalink)
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Originally Posted by PaleMelanesian View Post
Outstanding! Too bad I can only give you one Thanks for that post.


What he said.


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Old 04-06-2013, 02:29 PM   #22 (permalink)
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baseplate

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Originally Posted by Sven7 View Post
I've been thinking about this some more. Do you think a sedan owner could create a plexiglass baseplate sticking up vertically from the trunk edge, essentially creating a phantom Kammback? This would be less intrusive than making the trunk unusable but would it give meaningful drag reduction?
Could you do a 'back of the napkin' sketch,I'm having difficulty visualizing this.Sorry!
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Old 04-06-2013, 02:52 PM   #23 (permalink)
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I honestly don't think so:



Though perhaps a little depends on how high your vertical plexiglass plate rises from the trailing edge of the trunk lid?

james
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Old 04-06-2013, 03:01 PM   #24 (permalink)
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Cds

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Originally Posted by California98Civic View Post
I honestly don't think so:



Though perhaps a little depends on how high your vertical plexiglass plate rises from the trailing edge of the trunk lid?

james
I don't know the source of the pictorial drag table and associated Cds,but the numbers aren't in agreement with anything I've ever seen.
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Old 04-06-2013, 04:34 PM   #25 (permalink)
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Originally Posted by aerohead View Post
I don't know the source of the pictorial drag table and associated Cds,but the numbers aren't in agreement with anything I've ever seen.
Oh, darn. Nevermind. That's what I get for avoiding looking things up and just trying to get relevant info quickly. Sorry. But it is true that a vertical plate will have high drag, no?
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Old 04-06-2013, 04:55 PM   #26 (permalink)
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flat plate

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Originally Posted by California98Civic View Post
Oh, darn. Nevermind. That's what I get for avoiding looking things up and just trying to get relevant info quickly. Sorry. But it is true that a vertical plate will have high drag, no?
Yes,next to a parachute they have about the highest drag.
Hoerner,Fachsenfeld,and Hucho(who uses Hoerner) show around Cd 1.11 for a flat plate.
'Conventional' parachutes are Cd 1.35
A 1906 Buick Model C Touring Car was measured at Cd 1.03 according to Tremulis.The highest drag ever measured for an automobile.
CAR and DRIVER's Don Sherman who did the Crisis Fighter Pinto and Z-Car found that when rear spoilers went above a 30-degree angle(from the horizon)that drag began to grow higher.
The Guerney Flap is vertical,but does not project vertically very far.Maybe an inch for the Ford Torino Talledega of 1969.
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Old 04-10-2013, 11:56 AM   #27 (permalink)
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Quote:
Originally Posted by Sven7
I've been thinking about this some more. Do you think a sedan owner could create a plexiglass baseplate sticking up vertically from the trunk edge, essentially creating a phantom Kammback? This would be less intrusive than making the trunk unusable but would it give meaningful drag reduction?
Quote:
Originally Posted by aerohead View Post
Could you do a 'back of the napkin' sketch,I'm having difficulty visualizing this.Sorry!
I think he is talking about these. I've seen them used in autocross to impart downforce on the rear tires, but if they are properly sized, it may create the "Phantom Kammback" effect we are seeking.
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Old 04-13-2013, 01:41 PM   #28 (permalink)
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these

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I think he is talking about these. I've seen them used in autocross to impart downforce on the rear tires, but if they are properly sized, it may create the "Phantom Kammback" effect we are seeking.
Thanks for the images.
Since the context of the photos is 'auto-crossing',then I'm presuming that the racers are trading speed for downforce (since highest attained speed in autocross is relatively low in comparison to other track racing).
Every example shown would incur a MPG penalty.Careful 'tuning' of size and angle could achieve a drag minimum at zero-yaw,but in a crosswind the benefits would be dubious.
For $2,000/hour,at Lockheed-Marietta you could find out.Eventually.
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Old 07-25-2016, 04:25 PM   #29 (permalink)
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I got a tip of this saab study today:
http://publications.lib.chalmers.se/...ext/143210.pdf
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Old 08-22-2016, 09:54 AM   #30 (permalink)
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Quote:
Originally Posted by euromodder View Post
You'll find them here, amongst other stuff:

dropbox com/sh/52o49bkrua0tb5m/0qtRLnijtK/ecomodder_studies
Could you share this again?

Does someone have this files?
Thanks!

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