Full sized van boattails?
 

Related to the schoolbus topic almost... have people put "aerodynamic rear treatments" on full sized vans to see what kind of mileage improvement is possible? I'm curious for those who may have no alternative but to drive such a large vehicle (due to needs to haul cargo or whatever) whats possible.

a little bigger than your van, there is a guy here who has completely 'areo-ed' a big rig cab. He's doubled mpg from 7 to 13mpg.

That was a very good thread. How many of those modifications would work on my Subaru Forester? :D

Buy a van for $600 and go for it!

NASA did some tests a few decades ago.

http://spinoff.nasa.gov/Spinoff2008/images/t-6.jpeg

http://ecomodder.com/imgs/knox/nasa-van-z.jpg

http://spinoff.nasa.gov/Spinoff2008/t_3.html

Read threads by orbywan on his Class C motorhome. An EM gem.

Which user or/and subject titles are that specific guy? I see other people with RV related topics when I search but didn't see a big rig yet.

It might be worth looking at the Monaco Vesta MH for ideas. I met owners in OH recently. (blog post w/ pix) They said the company actually did wind tunnel testing! :)

Still searching,

I tried a search and could find him.

send carlos at cfg83 a pm. ask him who was the aero-big rig. (he knows everything!!)

YES!!!!!
THanks slow mover!:thumbup:

Wonders what it got at 55mph before treatments for comparison... the previous 5.8mpg average he quotes might've been typically running 75mph type of guys.. any idea what kind of improvements are possible simply through technique on these large vehicles?

I cant wait to see what happens when he closes the truck to trailer gap and sticks something on the rear of the trailer.

The aero improvement is so massive it seems like a must be. :P Whereas modern cars are not too bad off and improvements more marginal (10-15% usually) doubling mileage is pretty mindblowing. Does anyone have a guesttimate of how much it might be possible to improve a full size standard height van? The 6.2 GM diesel powered vans get 22mpg, i'm wondering how feasible 30mpg is with a diesel despite the frontal area ideally with mostly aero treatments. (not slowing down as much if possible)

pictorial drag tables
 

If you'll do a SEARCH for the full-boat-tail trailer thread,you'll find some wind tunnel data which I converted to pictorial drag tables.
You can look at what the investigators did,and the numbers it meant.
A 10% drag reduction will give you :
*5% increased mpg at 55-mph
*6% increase at 70 mph.
For speeds in between you can interpolate for a guestimate.