Date:         Tue, 30 Mar 2004 20:45:16 -0700
Reply-To:     Martin Jagersand <jag@CS.UALBERTA.CA>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Martin Jagersand <jag@CS.UALBERTA.CA>
Subject:      Re: On the Issue of Drag Coefficient Numbers for the Vanagon
Comments: To: FrankGRUN@AOL.COM

> 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)