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Old 01-26-2010, 06:44 PM   #13 (permalink)
KamperBob
Recreation Engineer
 
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Join Date: Dec 2009
Location: Somewhere USA
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Black Stallion - '02 Toyota Tundra 4WD xCab

Half Pint - '06 Yamaha XT225
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Quote:
Originally Posted by ChazInMT View Post
This brings up another point that I think people don't often consider. We spend a lot of time trying to make the tops of our vehicles as aero as possible, and often neglect the sides. The air moving around the sides of our trucks and cars has a large impact as well I say. On my Pickup, the sides are about 22" tall on the passenger cabin, just in front of the bed. The roof width at the top in this area is about 52" so with 2 sides at 22", that's 44" of air surface. So we worry about 55% of the equation and neglect the other 45%. This is why I have designed a taper in the sides of my aerocap when viewed from the top. Doing this results in a fastback design.
I agree. Look at most trucks' head-on silhouette. Height is comparable to width. But there are two sides to go around and only one top to go over. So my bet is more air pushes around the two sides combined than goes over. Sure some goes under too but that has to be the least given the road constraint. I think side profile analysis (top and bottom flow) is less than half the total. Top view analysis (flow on both sides) cannot be neglected on a truck if the real goal is optimizing in 3D. Cars? Maybe...

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