Wing pin handles, safety pin

The spring operated safety pin to hold the wing pin handle in place needed lots of work. First the cut out in the wing skin is all wrong, so the safety pin will be too far fwd and too much inward to actually do anything.

The safety pin on both sides needs to be re-positioned, and because there already are holes and cut out in the skin, a skin doubler needs to be made. Found some scrap metal to make this.

Then I looked at the safety pin itself. It is spring operated to stay in the locked position by default. A closer look reveals that the spring is only held in place by an insanely tiny clip that easily can be removed by hand. If this clip is removed, the whole spring operation will fail, and the pin can simply slide to the side. It's function will be lost. I decided to make an extra safety mechanism to hold it in place. My old man has built RC planes for almost a century, so I called him to ask if he had some piano wire. He had lots of it, and I "borrowed" some 1 mm wire to make a a small wire with loops in each end. One end goes through a m4 bolt in place of the rivet, and the other end can be placed around the safety pin to physically hold it in place. A very simple fix that should do the trick if the original clip should fail (until it rusts away, and then I will make a new one).

Reaming left wing

The lower pin hole.

Reaming wing pin hole

The I do it is to: First make the plates fit into each other by sanding a little here and there. Then put the wings together without the ribs on the inner section. With the ribs, the drill just won't fit. Then drill up the pin hole in steps to 9.3 mm (number U drill, or N?) This was done in steps, and was rather difficult. I finally got to use my Drill Doctor 500 to something useful. Then I used a adjustable reamer to ream the hole to correct size. How this is supposed to be done without an adjustable reamer is impossible to understand. I did this step vise by widening the reamer with 1/2 turn first, them 1/4 turn, and reamed until the pin just fitted. It is as good as it is possible to get it I think. I also polished the pin first, because that was not done from the factory.

The nylon pin guide needs to be coned up a little to allow the pin to get all through the holes.

Now I need to rivet on the outer ribs, and put the wing back on and ream up the other two holes.

One thing I have completely forgotten was that I had bought the wing pin kit from Ward also. This is with D=10.3 mm instead of 9.5 mm, considerable stronger. I can use that as a reserve in case the holes should widen with time. I don't know, I would probably rather use M10 bolt instead?