----- Original Message -----
Check this product out if you have a moment...
It is supposed to reduce turbulence and therefore drag at the rear of
vehicles and improve the laminar flow thus reducing fuel consumption.
Maybe it could have some slight benefit over long distances on
highways...can't see how it could help in stop start traffic where
fuel
consumption is greatest anyhow.
I don't think I want to stick or rivet them to my nice paintwork...
My cynic alarm is going off and the words "snake oil" keep popping
into
my head.
Anyway you be the judge....  http://www.fuelsavers.com.au/

actually, such a device was proven to lift the turbulant air flow from
the rear of vehicles and kinda kick it out a bit, lessening the drag a
ta. IPD (who made lotsa stuff for volvos) used to sell a
stick-on/magnetic version, but it was quite different looking ... ever
seen an NACA duct on the F1 race cars? sort of a swoopy triangle??
it's shaped very specifically to allow the boundary layer of air next
to the race car to be sucked (?) into the duct and then directed into
a radiator or whatever.

ok, now image that same shape (duct) but sticking OUT instead of in.
that's what the vortex generators from IPD looked like.
they even had some photos of the difference of a volvo sedan with and
without it. it did appear to lift the flow (from swirling and looping
directly behind the car) and smooth it out a bit.

now, whether even the IPD thingie would work on a bus, i don't know.
never saw anything about van vehicles.
but i was ready to try it!! ;) and of course, they quit selling it. so
apparently it (a) didn't work, (b) people didn't believe it
would/could work, (c) people didn't want that ugly thing on their
volvos, or (d) they fell off a lot. :)

and aircraft DO have vortex generators on the middle of their wings
(big aircraft, that is), but that's to create turbulance so the flight
controls work. :)

if anybody is interested in the NACA duct thing, this is what i
googled ...
http://www.recumbents.com/wisil/nacaduct/naca-duct.htm
some specs about shape/size.
http://www.stockcarproducts.com/naca.htm

http://www.up22.com/Aerodynamics.htm
and if you want to see a picture of something similar (but bumpier),
check out the 5th picture at
http://volvospeed.com/vs_forum/index.php?s=1041debaa0be3f82b20533dcf050255c&showtopic=16677
it's the red mitsubishi lance evo mr edition (he says). apparently
factory??

unca joel