Mailing List lml@lancaironline.net Message #61226
From: Jeff Peterson <jeffreyb.peterson@gmail.com>
Sender: <marv@lancaironline.net>
Subject: Light Pipe for Rear Position Light
Date: Thu, 01 Mar 2012 00:00:15 -0500
To: <lml@lancaironline.net>
To reduce the rudder counter-weight mass I made a "light pipe" system
for the rear-facing white position light.

The light pipe is 1/4 inch acrylic plastic (from McMaster Carr).
Weighs, oh maybe 10 grams.

To make the flair at the 'output' end, I clamped the end between 
two pieces of aluminum angle in a vice, then heated the angle with
a heat gun, tightened the vice, heated, tightened, etc. until I had an inch-wide wedge.

Squared that up a bit on the belt sander, then polished with 600, 1000, 2000, 3000
grit, then metal polish.  I also polished the flat input end.

Then I wrapped the both ends in aluminum tape.  I wrapped  the cylindrical section in between with
Alum. foil. (not shown in the photo)

The LED is a ~15 Watt (14V) unit that I bought from digikey or mouser.
It's mounted to a heat sink and sits forward of the hinge line. 
This more than satisfies the FAA brightness requirement.

Between the LED and the input end of the light pipe I use a dab
of silicone grease as an optical matching compound.

Super bright and very light.

Or you can place the rear facing position lights on the wing tips,
as on the Piper Tomahawk.

cheers,

Jeff Peterson
L 360 still painting
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