L.E.D. Lights in the Roll Bar
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This series of emails was sent to me by J.H. Phillips.  It concerns mounting LED's in your roll bar to provide internal lighting.

From: "J. H. Phillips" jhphillips@swbell.net   To: Doug Reeves vansairforce@hotmail.com 

Doug,
This is an email from Pete Pettis concerning installation of leds on the roll bar. 
Jay and I plan to do the same on my 6A and thought the details would be of 
interest to other builders.
John


----- Original Message -----
From: Loren Pettis  To: J. H. Phillips

John,
Sure you can post my e-mail.
A couple of things I thought about after writing it:
The dimmer I used is a kit (sort of like a Heathkit, from the old days) 
from Canada, normally used as a motor speed control. It works well, but did 
send a little buzz into my headset. Aircraft Spruce sells one, but it is a 
little expensive (the kit was about $12) and I bought a project box from 
Radio Shack to house it. Problem is I don't remember the web site where I 
found the kit. If I come across it, I'll send you a link.
The dimples I mentioned were made by clamping the appropriate size 3/8 
drive socket in the vise and laying the sheet metal on it. Then I used a 
hammer and a smaller size socket to make the dimple some creative tilted 
hammering can make dimples at all sorts of angles. I made several and then 
trial fit the lights until I found the one that gave the best aim. The last 
one is where I used the wedges. I said the sheet metal was .o2o, but it 
might have been .015 instead.

Pt

----- Original Message -----
   From: Loren Pettis    To: jhphillips@swbell.net 
 
   John,
   I am Rick's building partner.  I used these lights, from:
    http://www.nauticalworld.com/command/courtesy.html 
Command Electronics, Inc
15670 Morris Industrial Drive
Schoolcraft, MI 49087
Phone: (616) 679-4011
Fax: (616) 679-5410
part number oo2-o4B. They don't have on-line ordering, so I had to phone 
the order in.

   The LED is removable from the plastic housing and has a resistor wired 
to it. It is a 5 volt LED (the resistor allows it to work on 14 volts). 
They are designed to be used as courtesy lights on boats. You could use the 
housing, I guess. I removed the LED from the housing.

   I used a standard radio shack LED holder. I'm not sure of the part 
number (I bought it locally).

   You could just drill and tap the roll bar, but the angle you drill would 
have to be very accurate to aim the light properly. The light is fairly 
focused and one light will light about half the panel. I used three lights 
so that the light pattern would overlap. I used a small piece of .020 alum. 
sheet and put a slanted dimple in it. I drilled in the center of the dimple 
to mount the light holder. With some experimentation, I was able to rotate 
the sheet metal "mount" to get proper aim and then cut the perimeter of the 
sheet metal and roll it somewhat to fit the shape of the roll bar.
   I used an electronic light dimmer, though a rheostat would do just fine. 
I was just trying to save panel space.

   I also mounted two of the housings (trimmed a little) to the sides of 
the compass pointed downward to use as map lights.  
 They are really very bright. 
They produce an amber colored light that does not hurt your night vision. 
I "pop" riveted the sheet metal 
mounts to the roll bar when I was satisfied with the aim. Another way to 
aim them ( I did this on one) is to cut some thin wedges from aluminum 
tubing to mount onto the holders. Just saw a piece of tubing near the end 
at an angle and saw it again at 90 degrees. You have two wedges. It takes 
two (one in front of the sheet metal and one in back). Then the mounting 
nut. With this setup you just rotate the wedges to "aim" and then tighten 
the mounting.
   The holes in the roll bar for the back of the LED holder ended up being 
about 3/8". That is the one drawback to this design. The dust on the front 
deck is from the fiberglass work I was doing on the cowl at the same time. 
The plastic is still on the aluminum to protect it.


    There are probably easier ways to mount these lights (we discussed 
laying up some fiberglass). They cost about $6.50 each and I never seemed 
to have enough of them. Don't bypass the resistor and try not to bend the 
leads that come out of the LED's much as they are a little fragile. After 
you join the wires to them you might want to stiffen the leads with RTV or 
shrink tube. Look at the way the manufacturer did it in the original 
housing and you'll see what I mean.

   I also used two of these lights to light up the baggage compartment and 
Rick kept tempting me to mount two to light up the wing walk area. The two 
in the baggage compartment are in the top corners right behind the seat. 
The right one illuminates the left side and vice versa.
   They use about 1/4 watt each, so current drain is minimal. They really 
are quite sexy when all of them are lit up.
   Two things I tried to consider:
    (1) You don't want to be able to see the light from where you sit in 
the cockpit. They are brighter that you think. We have to turn the dimmer 
down about half way, to be comfortable as you can get some reflections off 
shiny surfaces.
   (2) routing the wires takes quite a bit of planning. Test your 
installation often with a battery to make sure you still have everything 
working. If you connect the power to the lights the wrong way (reverse 
polarity), they won't light up, but it won't hurt the LED unless you bypass 
the resistor.
   We have seen LED's that are mounted three, four, or five in a mount (for 
use as bicycle tail lights, etc.) about 1 by 4 inches that might be usable 
if mounted on the roll bar brace just forward of the canopy latch. Also 
there might be even more opportunities with the tip up canopy.
   I hope this helps. Good luck. Send us pictures of your project. We might 
want to use some of your Ideas.
   Pete Pettis.