Mailing List lml@lancaironline.net Message #11526
From: Gary Casey <glcasey@gte.net>
Subject: Landing lights in the wingtip
Date: Tue, 13 Nov 2001 05:32:40 -0800
To: <lancair.list@olsusa.com>
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The maximum operating temperature of the plexiglass I am using is 180
deg F.  From this experiment, I conclude that (1) the plexiglass does
not need to be cooled other that what it will get by traveling through
the air.  (2) The light fixture needs to be insulated from the
surrounding structure.  A 1/4" phenolic block should take care of this.
I will do a similar experiment to verify this later.

What do ya think?<<

Thanks for the real data - the world needs more of it.  I agree mostly.  The
160 temp of the lens is probably okay, but if the epoxy structure gets to
250 F it will definitely compromise its integrity.  You propose to insulate
the light, but that will cause its temperature to go up, possibly
compromising the durability of the light itself.  My thought was to mount
the light on a piece of aluminum - I am thinking of changing the insert in
the wingtip to sheet aluminum - to dissipate the heat out to a wider area
and consequently lowering the temperature.  Maybe what I should do is
combine both techniques - only join the light to the "heat sink" in a couple
of points, essentially partially insulating it, and then spreading the heat
out to the widest possible area.  Next thing I have to work out is how to
aim it as the little one-point mount is bulky and made of zinc.

The idea is to put the landing light as far out in the "pocket" as possible
and then rework the mounting of the nav/strobe light to be as far forward
and inward as possible.  The strobe lens will interfere partially with the
landing light projection, but I hope not too much.  I've seen some RV's with
this arrangement, buy they have a much fatter wingtip.  I think the small IV
wingtip would not allow this mod to be done.

Gary Casey
ES project.


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