Date:         Sat, 15 Feb 2003 21:05:24 -0500
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: back window - inside wide angle film
Comments: To: Roch2500@AOL.COM
In-Reply-To:  <184.16fc3668.2b7ff608@aol.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 02:59 PM 2/15/2003, Roch Roch wrote:
>I've seen folks with something on their back window, looks like a plastic
>rectangle that sticks on from the inside so they can see better.  Does this
>really work?

It lets you see stuff near the bumper pretty well, and is intended for that
purpose.  Essential on big RVs, useful on Vgons.  It also lets you see past
the rear-upper cabinet that restricts straight-back line of sight in Westys
-- but anything more than a few car lengths away is tiny, so it's not very
good.  A better solution for that would be a very thin wedge prism to shift
the view angle up a few degrees.  It could be a Fresnel design too, would mak

>   I don't know what it is called.

It's a form of Fresnel lens, where you essentially suck the middle out of a
big fat lens (concave in this case), breaking the surface into thin
circular segments and keeping the surface curvature of each
segment.  August (?) Fresnel was famous for building wonderful light-house
lenses using this general principle in ?early 19th c. ?


>Is there a preferred size?  Also some put in dead center, others more towards
>passeger side. ..which is better placement?

Try and see, they're easy to move -- basically wet the glass and squilgee
them on.  Preferred location for intended purpose is as low as possible,
possibly favoring curb side.  Bigger is easier to see but take up more of
the clear area of the window.  There may be a difference in power between
the sizes, probably the physically larger one will be less powerful and
show the cars behind a touch larger.


>Where do you buy?  Do they really stay

RV stores -- the expensive ones are made by 3M, cheaper ones not.  No idea
whether cheaper are as good.  They stay on fine.

>on or can they get moldy as some that
>I've seen are brownish around the edges.

dunno, sorry.  Mine haven't in about ten years in northeast US.

david

--
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"