At 04:37 PM 12/28/2002 -0800, you wrote:
>Ok, DML,
>
> I hafta double <snip> this one.
>
><snip>Of course, removing the tailgate eliminates *most* of that
> resistance<snip>.
>
><snip> Maybe, maybe not. Wind tunnel tests with a Ram showed that dropping
>the
> tailgate actually made things worse as compared with a tonneau<snip>
>
>I tend to disagree with the first statement & agree with Andy. There have
>been aerodynamic tests done with the tailgate up (& without a tonneau) that
>showed the design of the cab caused the airflow to furl around the cab &
>form an air mass which actually increases air pressure behind the cab. The
>result is a greater "pushing" force forward which slightly overcomes the air
>resistance caused by the front of the cab, & thus effectively lowering the
>air resistance in front of the vehicle...kinda like riding with the jet
>stream instead of flying against it...
>By lowering or removing the tailgate, this aerodynamic effect is reduced &
>the truck is actually slowed by the air mass in front of it...
>HTMS...
That makes sense to me, though I seem to remember reading some other test
results somewhere that showed relative changes in drag by removing the
tailgate vs. tonneau cover vs. camper shell, etc. that indicated a slight
decrease in drag by removing the tailgate. Oh well.
-Bill
This archive was generated by hypermail 2b29 : Fri Feb 06 2004 - 11:48:16 EST