HS skin dimple and cleco

I spent many hours in the last few days to prepare the skin for the horizontal stabilizer.

Dimpling

After cleaning, the first problem I ran into is dimpling. The DRDT could not reach a few holes on the skin to dimple, and I was afraid of really unbending the skin.

So I asked what to do on the facebook group, and most folks think extending the DRDT off the table would help, so I did.

I also needed to build a little jig to extend the flat surface to the left and right of the DRDT. The instruction for the jig actually came with the DRDT tool but I was just lazy and never had to deal with large flat surface parts before. But to properly dimple the skin I really needed a larger surface to hold it while I worked.

I went to home depot and bought a 2 x 4 x 3/4 flat board, cut it to size and quickly nailed it together.

With the jig and right positioning, the dimple became easy. Since there were lots of holes to dimple, it took me 2 nights to finish everything.

Here are some pictures during the work.

Fitting the skin

This is the more frustrating part. The skin is huge and it has to fit on the spar very tight. It was very difficult to align the holes and put in the cleco initially. But once I sent a few clecos, it became easier.

The instruction says “make sure there is no ripple”, however I just couldn’t get rid of all ripples completely. I re-clecoed everything at least 4 times in different order. There is still some ripple near the center.

I sent an email to Sling technical and they haven’t responded yet. I search a ton online and several discussion from Vans and Cessna seem to say it’s fine for airplanes at such low speed. I went to the airport today and checked out a few Cessnas. Some of them do have rippling so I guess I am not super worried. But I think I will still hold off the riveting until my EAA tech counselor comes visit. I will ask him what to do next week.