You have a point there; however, I did a 'real world' test on my Dak, and I
got slightly worse MPG with the tailgate DOWN. Not to mention you give up
some structural rigidity with the tailgate down (I've heard you lose some
traction in 1/4-mile racing due to more body flex??), and in many states
it's illegal to travel with the tailgate down (unless you remove it
totally). OTOH, I think a tonneau cover may be helpful, particularly for
lower-powered trucks that have to work harder at higher speeds (like a V6 or
I4 Dak cruising above 70mph); also depends on body/cab configuration.
As for extra weight, yes that might work once you get up to speed, but
you're losing MPG when accelerating that truck up to speed (and also
around-town driving). Since the quest for better aerodynamics is usually in
relation to MPG for trucks, the heavier weight idea would be moot.
I've an idea for an aerodynamics test: Build yourself two identical models
of your Dak and put a tonneau cover on one of them. Then go out to a deep
lake (the deeper the better) and tie the back bumper of each truck to a
fishing rod and let them drop to the bottom of the lake (remember, these are
toy models!) - the one that reaches bottom first should be more aerodynamic
(even though you are using fluid dynamics). Oh yeah, you'll need to add
enough lead weight to the inside of the truck with no cover so that the two
trucks weigh the same :-)
There you have it - your very own wind tunnel for next to nothing :)
'92 Dak CC 2wd 318 3.55
'84 GoldWing Interstate
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 12:15:58 EDT