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Old 09-10-2008, 04:16 AM   #1 (permalink)
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Ducktails

Can you advise if ductails promote "significant" increase in MPG?

How about spoilers?

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Old 09-10-2008, 10:48 AM   #2 (permalink)
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Stock spoilers (and goofy aftermarket ones), no. Ductail, potentially but not by much.
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Last edited by 2003protege; 09-10-2008 at 10:49 AM.. Reason: all aftermarket spoilers look goofy, not just "most"
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Old 09-10-2008, 02:02 PM   #3 (permalink)
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ducktail

Quote:
Originally Posted by gasti_ako View Post
Can you advise if ductails promote "significant" increase in MPG?

How about spoilers?
Ducktail is a new expression to me.Can you help me out with that?
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Old 09-10-2008, 02:06 PM   #4 (permalink)
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Ducktail is a new expression to me.Can you help me out with that?
I think he's talkin about a flat extension off the back of a car to lessen the roof-to-trunk angle

*edit* see this thread.
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Last edited by 2003protege; 09-10-2008 at 02:10 PM.. Reason: new link
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Old 09-10-2008, 02:10 PM   #5 (permalink)
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Quote:
Originally Posted by aerohead View Post
Ducktail is a new expression to me.Can you help me out with that?


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Old 09-10-2008, 02:22 PM   #6 (permalink)
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OOOOOH, ok....no they won't help.
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Old 09-10-2008, 02:26 PM   #7 (permalink)
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ducktails

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Thanks for the images! Without a windtunnel or tufting it's hard to say what the upkick does to the wake.I always lean towards the teardrop form,however in light of the VOLT rear spoiler mods(with the 5mm kick),if it works,it works!Some rally cars use extensive upward angles for rear downforce at the expense of drag.It's hard to know where the boundary is.
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Old 09-10-2008, 07:15 PM   #8 (permalink)
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the initial concept car didn't have the "ducktail" so i don't think it was added for looks alone
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Old 09-10-2008, 08:36 PM   #9 (permalink)
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What about a ducktail, angled down about 12 degrees instead of up, off the cabin roof of a conventional sedan?
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Old 09-10-2008, 09:08 PM   #10 (permalink)
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What you call 'ducktail' is a trip spoiler. It's used to keep at bay aerodynamic lift at the rear of the car, which can be dangerous when cornering at high speeds if the stern loses grip.

The 'ducktail' trips the boundary layer prematurely, assuring no aerodynamic lift would be generated.


This can be critical at high speeds. The original Audi TT had an aerodynamically poorly designed very rounded tail that in itself generated lots of lift at high speed. Audi screwed big time on this. The first production models, without rear spoiler ...



... suffered some fatal crashes while cornering at high speed (180kmh/112mph +) in the Autobahne. Even a known race driver was killed. Audi was forced to recall and fit an inprovised spoiler ...



In the 2nd generation TT they solved the problem with a retractable spoiler, which deploys at high speed:




Unless you need them to corner at high speeds, these devices just increase drag (by enlarging the wake area) and fuel consumption. At 55mph they are perfectly useless.

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