Blueskies wrote:
"Morgans" wrote in message ...
"Blueskies" wrote
I forget which brand truck we were looking at (Ford?), but it had a sculpted shape to the top of the tailgate about
8" wide. The salesman said it helped to improve gas mileage...
He was wrong. It is to provide extra clearance for people towing 5th wheel or gooseneck trailers.
--
Jim in NC

No, it was not a 5th wheel clearance thing. I did not describe it very clearly. Regular rectangular tailgate with a wide
upper (top when closed) edge...



You see it on a lot of trucks. It used to be that a box van was just
that, a box. A decade or so ago, they started rounding the front edges
of the box. Can you say "fairing". Some started rounding the back
corners also. I've seen SUV's with what looks like reverse scoops that
could have to catch the air passing over the top of the vehicle and blow
it down the back. Counterintuitive until you realize that attached flow
offers less drag.

The thick tailgate with the rounded edge keeps the air in attached flow
longer. Even a small amount, just a few inches, offers major
improvements over the previous generations 90 degree chop offs.