Interesting read on pickup truck aerodynamics.
 

It seems the geometry of a truck bed has a great effect on the Cd of the pickup truck. This research paper presents some interesting wind tunnel data and explains why later model pickup trucks have such high side walls and tailgates.

It seems the manufacturers have sacrificed the utilitarian aspects of earlier model pickups (with low side walls and tailgates) for the taller bed height we see on the late model pickup trucks, especially those trucks with the shorter beds. It's all about reducing the Cd of the pickup truck to improve the fuel efficiency of the truck.

http://www.wseas.us/e-library/confer.../FMA/FMA17.pdf

Happy New Year and may 2011 be a good one for us all.


Bondo

Interesting.
Makes sense though. Same principle of why wagons and stretch limos get better FE.
Apparently flow reattachment over length is more important than I thought it was.

That would explain why all of those late model pickup trucks have such high beds. They're almost like open-topped versions of the traditional van body.

bondo -

Great find! Do you think that this stuff like this could be a missing detail in the "tailgate up/down" theory? That is, it depends on the length of your bed (the geometry!) :

http://ecomodder.com/forum/member-cf...eamline-03.jpg

What do you think?

CarloSW2

yea i guess that makes sense after i think about it

Thx Bondo and cfg83.

I thought the high bed walls were for a more massive/macho look.

That does not explain why the body is jacked up and why the frontal area of a truck is so big! even the little Toyota trucks are a half ton truck, just like F-150's and Toyota made a 1 ton truck that wasn't much bigger then their half ton truck.
That paper seems to agree with the van shape but the big problem with trucks is that you need a step ladder to get in to the truck bed.

It may very well be. You have now attached a theory to a theory but it does make sense. Your graphic does a very nice job of explaining your thought.

That is definitely thinking oustside of the box!


Bondo

This would militate toward the sloped sidewalls of the GM Avalanche.

I suspect they did not get high for aero; they are high because of the ginormous wheel/tire packages driving the entire chassis up. The cabs are higher too.