Wing - Ribs

2004-01-15 - Drilled wing conduit holes. (2.0 Hrs).

I'm back working on the wings, since I finished laying out my circuit boards for my nav/strobe lights. I ordered boards and more LEDs.

I drilled the holes in all of the main wing ribs for the wiring conduit. I decided to drill the holes between the two largest holes. One in the upper part of the rib, and one in the lower part of the rib. Van's instructions suggested to enlarge the rib tooling hole, but I looked at this pretty close, and there is no way to get the conduit through there. The aileron bellcrank gets in the way. The spots that I chose are above and below the aileron push rod, and do not interfere with anything that I can see.

I decided to drill two holes in case my LED strobes do not work out and I have to use regular 350 volt strobes. I am planning on putting the comm antenna in one of the wing tips, and I do not want to run the high voltage strobe line next to an antenna cable. I'm hoping that 6" is enough separation. If I need just one line, I can decide at the last minute which to use.

Per some other websites, I made a template to help drill the holes in the same spot in each rib. After two ribs I figured-out that the easiest way was to drill two ribs--one left, and one right. Then all you do is use the left rib as a template to drill all of the right ribs and you use the right rib to drill all of the left ribs. Simply hold the ribs back to back.

BTW, I like Van's conduit, because it is not split. I found plastic conduit locally at Home Depot, Harbour Frieght, etc, but all of them are split. The split might make it hard to suck a new guide string down the tube later on. I know you should tie a string in there, but strings tend to fall out.

Left and right rib, back-to-back. Initially, I used two drills as guides to help align the ribs, but this is not needed. Simply match-up the tooling holes, hold the ribs by hand, and drill the new holes. These don't have to be perfectly matched. The conduit will bend. I just don't want to be too sloppy.
Next, you use a unibit to enlarge each hole. My unibit is not quite big enough for Van's conduit, so I have to use a deburring tool to finish enlarging each hole. I only enlarged two ribs today, so I still have a few to do. I can see this is going to take awhile to finish.
I bought two inexpensive steel eye bolts from Home Depot, so I tapped the hole for the eye bolt in one of the wing tie-downs. They look pretty strong, but they are not cast iron like Van's. Then again, $.60 .vs. $3.50 (each).