First coat is brushed on after a wipe down with MEK and a tack cloth. Marie pitched in to help with the tack rag.

The first coat is brushed on (why it’s called poly BRUSH) and it soaks through the fabric.

While waiting on my mechanics helper (Marie), I removed the old fabric from the left aileron. Other than just dirty it looks really good.

Updated 12/1/2020: Watch the 3D printed flap bracket installation video I made here: https://youtu.be/4v0zpSS4QO8

These are hard to find so I designed and printed a few. They came out pretty nice I think. Plastic is ABS so they’ll withstand the temps and I printed a set in flex filament. They came out nice. They are there to keep you from scalping yourself when you walk under the wing.

I understand the factory put these on the 108-3 models only. I’m not sure if that’s accurate as one guy I spoke with has them on his 108-1.

Now I’m making a mold so I can make them out of rubber. I’m using a rubber with a hardness or shore value of 80A. Hard, but flexible. It should prevent scalping yourself. Is there a market for these?

Update 12-01-2020: Lucas from Univair called me back. He’s been very helpful, but can’t give me a good answer on how to set the drag wire tensions. He gave me a name of an engineer at Univair (Mike Wotovitch) who I haven’t called yet, but Lucas talked to him and said I could call to discuss it with him. Apparently, everyone who would have known is either retired or worse yet, no longer with us.

Update 11-30-2020: I spoke with Lucas at Univair and he thinks the right wing drawing (-1111001-1DWG, at $154.54!) they have contains the info for the drag/anti-drag wires. I also spoke with Gary Redden and he doesn’t think so. Lucas is going to open the drawing when he gets a moment and check it for me.

To mark the measuring points, I drew a line straight up from the centerline of the compression tube to the front and rear spar with a square, then marked the point midway on the spar and made a T. The spar measured 1 1/2” so I placed the mark at 3/4”. I did this on each section of the wing. The wing root bay was hard to do because of the drag wire attachment point being behind some brackets.

Then, using my trammel device, I measured each bay from those points. One Piper owner said to start the measurement from the wing attach point using a bolt for the first measurement.

I read a post on the Short Wing Piper Club about checking the drag wires and it matches with what I’m doing, pulling the wire 1/2″ at the center of the bay and reading the tension. – jlk

Wow. Not much information out there on this subject. I had a wing drag wire that was loose and I tightened it up. Now I need to make sure the wing is straight and the drag wires have the correct tension. The maintenance manual only provides the drag wire tensions, but not how to set them.

Now, the wing drag tension is a bit tricky. Again, nothing in the manual on this except the tension values. Nothing on how to check them. I watched a video by two gentlemen ( https://www.youtube.com/watch?v=X2fU-1TQg-g )checking the drag wires on a cub and this was their setup. Not sure if the 1/2” pull distance is the same for the Stinson wing. The Stinson service manual provides the tension settings for each bay, but that’s it. I guess this was common knowledge back in the 40’s, but it isn’t now.

The bay I’m testing in the photo is the third bay in from the wing root. The book says 82 lbs of tension, so about 7 ft/lbs of pull. I’m getting 10 ft/lbs on both wires. I’m guessing that if both wires have an even pull and it’s close, it’s good. Any comments?

The manual tells you to prime the surface with their EP420 primer so the fabric has a good surface to adhere to. so I painted the top and will spray the bottom later. Three light coats.

EP420 requires a catalyst, EP430, and a 50% thinner to spray it through a gun.

It’s always good to have someone else look over your work. Cousin Doug stopped by today and pointed out a couple things I could improve upon.

One was the pitot/static tubes going over the spar tube. It originally had black cloth tape on it to prevent chaffing. I cleaned it up and applied some felt tape in its place.

The other spot I’m still working on, but it is some of the leading edge wing aluminum that has some oil canning happening. I’m installing a fix to remove it.

One step closer to covering. Cutting my fabric to size.