Date:         Sun, 18 May 2008 08:12:03 -0700
Reply-To:     Don Hanson <dhanson@GORGE.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Don Hanson <dhanson@GORGE.NET>
Subject:      Belly pans for speed /mpg
Content-Type: text/plain; charset="Windows-1252"

  While the vanagon might just be the worst-shape possible for efficient
aerodynamics,  small improvements add up.  Maybe the Sprinter vans are worse
shapes..The Aztec has to be pretty close, and the Scion is no Ferrari,
either.

  The "details" do make a difference, however.  Small changes or
improvements add up.
  Smoothing the underside of a Van would certainly show some measurable
improvement in it's aerodynamic efficiency..thereby giving it more top speed
and better gas mileage.  For the amount of 'work' involved in fabricating
something for the underside of a van, it might be worthwhile doing.  With a
vehicle lift and some basic tools it'd be pretty simple to fab up some kinda
belly pans that would work well.

  It is pretty amazing how small aero details can make a difference.  I used
to laugh at the lengths my good friend and engine builder went to with his
Porsche 928 for the Open Road events..But he's now a member of the "200mph
Club".  He would spend hours, after arriving at a race in Nv. taping up his
car, removing mirrors, wipers, etc.  Then when we, too,  "moved up" to the
Unlimited Class, I found he was right on by attending to those details
before each speed run.
  Mirrors on?...Lose about 15mph.  Windows down?  at least 25mph.  Nose of
car set too low?  10mph..  One size wider tires? 10mph..It all matters.  As
you get into the highest speeds, it matter even more..(speed is also related
to 'cubic dollars'.)
  So if one was to keep a van for another 20 years, after putting on some
undertrays, you'd certainly save on the fuel, even if it was just 2/10s of a
mile per gallon..  I bet filling that luggage space in a Westy top might
help a bunch also.  The front of any vehicle is the most important, because
any vortex or turbulence created at the front end continues to create drag
all the way back over the whole shape..

  Somewhat interesting is the fact that as racecar aerodynamics have
improved, the 'wing' has been eliminated.  The Wing, on racecars, was used
to increase downforce..the car's ability to generate traction by using the
air to 'push' it down onto the track.  Now, the engineers have refined the
underside shape of the racecars to generate the same downforce. essentially
by shaping the car's underside like an upside down airplane wing..and
creating 'negative lift' to pull the car down onto the track...

  Don Hanson