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Old 02-09-2011, 01:56 PM   #91 (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 BamZipPow View Post
I would still put some sort of taper from the front to the rear. I have found out with mine that if I could just pull it in just by a few inches that it would be better in the long run...even if it's just the same width of the tailgate. This will be incorporated in my next version...
BZP, can you say more about what you found out regarding side taper? I am keenly interested in the basis for your view. What do you know that I don't?

I am concerned about discontinuity between bed and topper sides. Both start under positive pressure from displaced airflow. The bed sides don't change surface area or angle (much) over the bed length (ie, versus time in the flow field) so that pressure remains relatively consistent. An aerocap by contrast decreases surface area progressively from front to rear, which in turn reduces pressure. The resulting vertical pressure gradient encourages some air to flow upwards. In doing so it must roll over any discontinuities in vertical profile. Shoulders without sufficient relief radius create potential for flow separation. Especially towards the all important rear end of the vehicle where crisp detachment is desired in preferred directions to shape a converging wake. Does this compute, or am I all wet?

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Last edited by KamperBob; 02-11-2011 at 07:59 PM.. Reason: typo
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