Date: Wed, 5 Sep 2007 08:56:49 -0700
Reply-To: Mark Keller <kelphoto@TELUS.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mark Keller <kelphoto@TELUS.NET>
Subject: Road stabiliy issues or swaying in the wind
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Hi Gang,
While this discussion on wind sensitivity isn't new, nor are my
comments, I think they should be considered. As a somewhat qualified
marine tech, the issue of stability is often addressed with vessels.
The issue is primarily of weight distribution. High up =bad and in the
ends of the vessel = bad. And of course out of trim laterally as well
as for and aft= bad. All possible high density items stored should be
as low as possible, and centered, as a general approach, exceptions do
exist. Given the above, think of your van as "floating", ie without the
aid of 4 tires to keep it upright. If your still with me, the
"righting moment" is what now governs your vessels ability to maintain
trim in a seaway. A vessel with gravity centers high and or fore or
aft, with have very long recovery from wind and wave stimulas.
I'll bet savvy westyites put the fluffy stuff up top, including the
cabinets, and put the dense stuff on bottom, and they move every dense
thing possible to the passenger side low, and avoid putting heavy
things in the aft.
While its not possible in a short missive to cover trim, moments, and
stability issues, the above comments will useful in thinking of
stabilizing your van.
Another issue is fore/ aft weight bias, much has been said about our
vans being in the 50/50. While this is a contradiction to what I said
above, the fore /aft weight bias, for stability is better biased to the
front. So if you can move as much weight forward, stability will
benefit. A good demo is to take a shopping cart for a spin. Try
loading with bias front and rear and central. Use milk and such.
Notice how easy steering is with the bias aft and central, and difficult
with the bias forward. Stability because of forward weight bias, like
all car and truck designs except ours, occurs because the polar moment,
or spin axis, is forward of the center of the vehicle!
Lastly is caster adjustment on the front end alignment, more caster,
equals more stability. Have it checked or even tweaked by a good
alignment shop as well as the camber and toe in. A good front-end
tech will be able improve your setup for optimum stability.
Mark Keller
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