Wing Chapter Supplement
Installation of a Landing Light in Wing Leading Edge
By Bill Schertz, KIS Cruiser #4045
The prototype KIS Cruiser did not have landing lights, therefore the installation is left to the individual builder. In order to provide some input for future builders, I am documenting in a "how to" description the method I used for a landing light in the wing leading edge. This modification is not in the standard KIS Manual. The information described below is strictly for the discretion of the individual builder.
I will attempt to explain some of the design considerations that entered into my choice of method of construction.
Landing Light Choice
This is the same bulb/light combination that Dave Tate used, and a picture was included on Bob Reeds web site of Daves installation.
Landing Light Location
I positioned the opening 3 inches inboard from the outer wingtip joggle. I felt that this "looked right" in terms of its location relative to the wingtip strobes and running lights. This location is arbitrary.
Other Considerations/thoughts
I was concerned with the mounting of the lights. They have a threaded bracket on the ends of the light, and if possible I wanted to use that. I also wanted to be able to adjust the aim of the lights a couple of years down the road when I complete the airplane. I was also concerned with heat build up in the leading edge on the composite structure, therefore I wanted to design a mounting system that promoted cooling of the lights.
Mounting instructions:
FIG. 1 Opening in leading edge for Landing Light
Figure 3 Landing light components shown
Fabricating the Flange
John Petrie (from South Africa) mentioned the use of "calibrated wax" to set the depth of the flanges equal to the thickness of the plexiglass cover. This technique works quite well, although there are a couple of "gotch yas" available. Calibrated wax is a product that comes as a sheet of wax (1/16", 1/8", etc.) with adhesive on one side. It is available from McMaster Carr in Chicago via mail order. [I bought the 1/16" sheet, and used two layers to get the 1/8" needed for the plexiglass. That way, excess material can be used for other applications where 1/16" would be the required thickness.]
Cut 1" wide strips of the wax. Using the rolling "pizza cutter" works well.
Figure 4. Aluminum flashing taped around opening
Figure 6 Clamps of Al-angle held long straight edges in place nicely, but
the "sag" was on the curved surface lower edge.
Figure 7 Showing the flange and light in place
Figure 8 Illuminated!
Temperature Rise Concerns
Because of the confined nature of the light, and the fact that it dumps 55 watts of electric power into the space, I was concerned that the temperature might rise to an unacceptable level when in use. To get a handle on this, I did some experiments. I purchased an "indoor-outdoor" digital thermometer, and put the outdoor probe between the back Aluminum plate, and the fiberglass spar. Then I sealed up the lense, and turned on the taxi light bulb (they are both 55 watt bulbs). I monitored temperature with time, and the results are shown below.
After 30 minutes, the temperature rise was slowing, and I then put a small fan 28" from the leading edge, simulating a gentle breeze across the wing. You can see the effect on temperature. I feel that in actual use, with a plane moving at ~100miles per hour, that temperature will not be a problem
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Time, Minutes