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Old 05-09-2015, 01:55 PM   #11 (permalink)
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Originally Posted by gumby79 View Post
another reason for the pinch front . Snow. .. if the tires of the truck pack snow on the inside = bad
I was going to mention curbs as well. If the truck runs over one, the skirts tuck under, versus tearing off.

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Old 05-09-2015, 02:55 PM   #12 (permalink)
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out of the wheelwell

Quote:
Originally Posted by MPGomatic View Post
Great stuff, Aerohead! What about influencing the air that comes off the tires out of the wheelwell/away from under the car with a gentle sweep by integrating a small flap at the back of the wheelwell that blends into the skirt? Instead of a 90 angle, it might be 100?
On the T-100 I did a crude representation of the Scaglietti (Ferrari) edge radius off the back of the front wheelhouses which has seen service on many cars,including the 1st-gen Insight.


I believe that they're especially beneficial in crosswinds although I'm not sure about zero-yaw conditions.
If you can get the air to round the nose onto the flanks of a car,it tends to just flow back and jump the wheelhouse opening.
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Last edited by aerohead; 05-09-2015 at 02:56 PM.. Reason: add second image
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Old 05-09-2015, 03:13 PM   #13 (permalink)
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McLaren

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Originally Posted by whatmaycome14 View Post
Aerohead, I appreciate what you've said, but it stirred a question in my mind. I couldn't help but notice that on the bottom of the McLaren mp4-12c has some very short "skirts" behind the front wheels. Is this at all related to the fact that the car doesn't have any side skirts hanging that low?

https://inthemetal.wordpress.com/201...p4-12cs-floor/
The McLaren is low,and subject to ground strikes,and to keep customers happy no doubt have had to be careful that in day to day driving,the car doesn't lose all utility.
The skirts they have help channel air for the rear cooling functions and they are Whitcomb-waisted to moderate pressures along the pathway.I suspect that they spent $100,000 developing them.
These supercars pay particular attention to high speed stability,low drag taking a back seat on priorities.
Sports cars lead low drag design until the Maxda GLC entered the market.Ever since,the average,entry level passenger car has had lower drag than these ubercoupes.
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Old 05-09-2015, 07:09 PM   #14 (permalink)
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Are those behind the front wheel or ahead of the rear wheel?

That's the shape I was suggesting for the back edge of the front wheelwell. But in this case it looks like it feeds the rear diffuser.
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Old 05-09-2015, 11:23 PM   #15 (permalink)
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Quote:
Are those behind the front wheel or ahead of the rear wheel?
both
they start in front of the wheelwell and travel past the wheel well then turns out. stableize air under the belly pan From thewheel wash and brake heat and re direct it out . spread causes a low pressure (high negative force =down force) center of Mass
I also see a trip edge around the the rear fairing
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Old 05-10-2015, 01:07 AM   #16 (permalink)
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I too was gonna mention the early Insight fenders. Lots of that style on race cars, both professional and the more serious amateurs like on clubroadster.net

That being said, I think Aerohead is right but for a reason nobody's mentioned. The wheels of an OTR tractor go UNDER the trailer when turning sharply. Skirts can be longer but angled in or shorter but stay straight. The landing gear is "break-even" point for trailer skirts whereas on a car or straight truck you can keep the skirts flush to the outside of the tires, which is a benefit whereas the narrower trailer skirts are a compromise.

Seeing the popularity of having dozens of license plates on an OTR truck back in the 70s might likewise lead posters here to believe if the truckers have lots of plates, we should too because they wouldn't do it if it weren't good...but that was another compromise truckers had to make and to copy it would've been foolish.

Next someone will say "yeah I like those angled trailer skirts so I'm doing that for more mpg and also dupicating the 15 liter engine cuz trucks wouldn't have those if they weren't good for mileage"

I do think the 8 tires at the rear of the truck and the necessarily large open area around them is a big source of dirty air and the fairings being stuck inside that is probably an attempt at getting all that air going in the right direction again but unless your vehicle has 8 such tires at the front, I don't think angling your side skirts is going to benefit you.


Last edited by mwilliamshs; 05-10-2015 at 01:46 AM..
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