Date:         Tue, 30 Mar 2004 23:16:51 -0500
Reply-To:     Joy Hecht <jhecht@ALUM.MIT.EDU>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Joy Hecht <jhecht@ALUM.MIT.EDU>
Subject:      Re: On the Issue of Drag Coefficient Numbers for the Vanagon
In-Reply-To:  <S563096AbUCaDpQ/20040331034523Z+112@sunkay.cs.ualberta.ca>
Content-Type: text/plain; charset="iso-8859-1"

Why not kill two birds with one stone by designing a storage unit (bag?
box?) shaped to be more aerodynamic than the existing well?  Not just a
cover...

I have a bag up there that I made.  It's not aerodynamic, I'm sure, just
lumpy.  And I also have my kayak above that.  FWIW, my gas mileage is no
worse with all that stuff up there than it was without it.  The van does
handle worse - I think that's wind catching the kayak from the side.  To my
surprise, the kayak has more impact on van handling than it had on the
handling of my Prius or my Civic, where there was 3-4 feet of overhang at
each end.  I guess that's simply because it's so much higher.



Joy

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Joy Hecht
and Matilda, 1989 Burgundy Vanagon
and Henrietta, sad-eyed orangutan who waltzes with Matilda and me
and Bicycle and Kayak, who ride on Matilda

For musings about life and the vanadventures:
http://users.rcn.com/jhecht/gypsy
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM]On Behalf
> Of Martin Jagersand
> Sent: Tuesday, March 30, 2004 10:45 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: On the Issue of Drag Coefficient Numbers for the Vanagon
>
>
> > the later Vanagon with front spoiler lip,the values are: 0.44
> and 3.08 m2;
>
> > for the Westfalia, the numbers are 0.52 and 3.17 m2;
>
> To mee it looks like the reason for the worse number for the Westy
> is the front luggage rack. Anyone thought about making a cover
> for it that would allow for a smooth transition from the front
> to the roof? Even better, anyone knows how to actually calculate
> a shape that would avoid cavitation and extra drag?
>
> Subjectively it feels like my '82 westy "hits an air wall" at about
> 120km/h. Wind noise goes from quiet at 90 km/h to moderate at 100-110
> to deafening at 120km/h and over. Can't even hear the engine, which
> itself isn't exactly quiet with fully open turbo wastegate and
> 2.5" Dynomax performance exhaust.
>
> The relative Cd ratio .44/.52 = .85 suggests that a 15% reduction
> in drag should be achievable if somehow it is possible to restore
> good airflow around the westy luggage rack.
>
> Anyone has a solution?
>
> /Martin ('82 Westy 1.9TD and '94 Westy 2.5l)
>