The biggest thing I can say about the wingtip fiberglass is to take your time and ensure everything is positioned correctly before you cut.  I spent a lot of time fitting before I drilled the first hole.

Prep

I inserted the aileron jig back into the bellcrank and also aligned the tooling holes in the wing ribs and ailerons.  I used some clamps on the bellcrank and jig to ensure the ailerons maintained the proper position.  Once I knew I had the ailerons perfect, I moved on to the wingtips.

Fitting

First thing I had to do was get the wingtip to slip into the end of the wing.  I had to sand the end of the tip at a few spots to prevent it from bottoming out inside the wing before the lip was tight to the bevel.  I also had to do a little fine sanding with a file where the bevel had gotten rounded over or where resin had dripped.

Next, I spent a lot of time wiggling the wingtip until the trailing edge lined up with the aileron, and the front fit snug inside the front curve of the wing.  This took some doing.  I clamped a couple of bards onto the top and bottom of the aileron to help hold the tip in position there. (Kind of like I did with little strips of metal that I side grip clecoed to align metal parts).  I had to use duct tape to help prop up the middle of the tip, or else when it sagged the front alignment was changed.  Eventually I had the right fit all the way around.  The front curve was nice, and the trailing edge lined up with the aileron.

I also had to remove some material from the inside of the aft end (right next to the aileron.)  At this point, I removed as little as I could get away with to allow the wingtip to fit on.

Tin Canning

That’s right, I actually had some tin canning on my wingtip fiberglass.  I used a heatgun to get the shape I wanted.  Click here for more on shaping fiberglass with a heatgun.

Drilling

I then drilled the holes.  Here is where I had the first problem.  I didn’t have edge distance on the W-412 ribs.  So I added some extra metal strips.

The rest of the drilling, dimpling and riveting platenuts was uneventful.

After the wingtip was drilled, and clecoed into position, I marked and cut the inside aft edges.  I marked 1/16 inch from the front and trail end of the aileron, then connected the dots.  I trimmed off both the fiberglass and the metal behind it.  This ensured I had a uniform gap between the tip and the aileron.

You can see that the fiberglass tip is a little longer than the aileron.  I will trim this to final shape as I do the final prep-work before I paint.  Click here for more my thoughts on  final fiberglass work before painting.

Final stuff

I also installed the wingtip antenna and lights before I screwed the tips on for the last time.

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