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Old 06-26-2010, 04:01 PM   #8 (permalink)
aerohead
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birdbath and Yoda

Quote:
Originally Posted by JaronLindow View Post
I made a 2nd attempt at a bed cover using a flat 4x8 sheet of wood strapped to a metal frame.

The front is just low enough to see over and the rear touches the end of the tailgate.

I tested with and without a simple vortex generator taped to the cab. That didn't make a noticeable difference.

Tuft testing showed the airflow along the rear half was moving to the sides rather than backwards, which was a surprise.
If you had been running a soft tonneau cover you would have noticed that the back half would have a birdbath depression in it,and the area behind the cab would be bulged up,as if Yoda were underneath trying to escape.
It's the classic pickup vortex with air slamming down at the back and then back-feeding onto the stationary low pressure vortex spinning sideways behind the cab ( dancing beer cans ).
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