Date:         Fri, 26 Sep 2008 20:33:09 -0700
Reply-To:     Michael Snow <slowmachine82@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Michael Snow <slowmachine82@GMAIL.COM>
Subject:      Re: Why don't we have these kinds of Pop top here in the USA
              "Atlantic "
In-Reply-To:  <5ebe10a0809261904h59dc4102m76eb3a0d701b71f4@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

You've caught me in an analytical mood, and on a Friday to boot.

Chris, I'm sure that it is measurably higher, but seriously doubt that
it is *much* higher.  I'd bet that the difference in aerodynamic drag
is less than 10%; and aerodynamic drag is only one (admittedly,
significant at highway speed) component of total resistance to forward
motion.  The sunroof design isn't shown on the handy chart that you
link to.

And Roger, comparing the driving characteristics of three different
vans with different roof designs is not a legitimate way to evaluate
the roof design.  Driver's seat data might be minimally credible if
all three roof designs were tested on the same chassis and under
reasonable similar conditions.  Anything less is simply anecdotal.
Heck, I've driven the *same* diesel camper with 2-3 different 1.6D
engines, with the exact same transmission and cargo load, that drove
*very* differently.

--
Michael Snow
1982 Westfalia 1.9TD
http://slowmachine82.blogspot.com/


On Fri, Sep 26, 2008 at 7:04 PM, Chris S <szpejankowski@gmail.com> wrote:
> The front luggage rack creates a LOT of turbulence and drag.  Yes, frontal
> area is the same but with the rack the drag is much higher.
>
> http://i16.photobucket.com/albums/b7/misterpolak/Misc%20VW%20nuttiness/windtests.jpg
>