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 Sailplane Construction Project Session #128

Comet Sailplane Project
Before starting the preparation process for covering the cowl and fuselage, there were a couple of items that needed to be worked out. First of all, a drain hole was required in the bottom of the cowl. A small hole was drilled in the bottom of the cowl near the rear bulkhead. An 1/8" I.D. aluminum tube was CA'd in the hole being flush inside. Then the end of the tube was filed off flush on the outside as shown below. 
The second item on the cowl that needed attention was to provide an outlet for the high tension lead. Again, a hole was located and drilled in the top of the cowl. An aluminum tube large enough for the high tension lead to slip through was CA'd in the hole and filed off flush on the outside as shown below.
This picture shows the red high tension lead coming through the outlet and attaching to the spark plug.
Next I started preparing the fuselage structure for the first covering of Polyspan Lite. The fuselage will be covered in essentially four sections, top, bottom, and the two sides. Therefore the covering will be spliced down the length of the fuselage along the four longerons whose corners have been beveled to act as stringers themselves. As you may recall, my doping procedure is to coat the structure with a mix of 50% clear nitrate dope / 50% nitrate thinner three times with light sanding in between coats. As I was putting on the first coat of clear dope on the fuselage structure, I became aware of how narrow the footprint or edge of the beveled longerons where the covering splices will be made. The widest edge is only 3/32" as  shown below. It is going to be tricky, if not extremely difficult, to cut and splice the covering materials along and down this thin edge. Something had to be done to improve this situation to avoid a potential covering disaster. 
The fix that I came up with was to carefully position and glue a 1/16" square balsa strip down the entire length of the longeron along the outside beveled edge as shown below.
The edge  1/16" square balsa strip was trimmed off at the same angle as the longeron bevel and then sanding down flush. This produced an edge that was now 3/16" wide as shown below, which is sufficient for cutting and splicing the covering materials on........................Tandy

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