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Old 02-25-2015, 06:42 PM   #7 (permalink)
aerohead
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various lengths

Quote:
Originally Posted by craveman85 View Post
Has anyone tested various half tonneau lengths? Maybe also on various bed lengths? Or does half of any bed length seem to be perfect?
In the original 1986 US Patent,GM offers a drag table showing the change in drag coefficient,from zero,to full length.
*Any coverage,of any length provides a drag reduction.
*The drag minimum occurs at 50% (half) coverage (back half).
*They tested on a C-10 1/2-ton.
*The half tonneau gave a 8% drag reduction.
*The full-tonneau gave a 5.6% reduction.
*The 1/2-tonneau with forward bulkhead had 12.8% higher drag.
*And the 1/2-tonneau cut rear lift by 30%.
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In 1988,Texas Tech investigated the tonneau and also advocated the 1/2-tonneau.
If you need numbers for various bed lengths you're on your own.
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