Today, I worked a bit by myself to get ready for Craig to come by again and help me finish the top row of leading edge skin rivets. When doing his wing, we discovered that the second most outboard skin overhung the landing light opening significantly and would cause an issue with its installation. Since this part of the skin was causing a problem and didn’t attach to anything, we decided it would be okay to trim off. That worked although Craig gave me the advice that he wished we had trimmed a bit more since it made the light housing sit slightly crooked due to the extra material under the outboard side.
I thought it was weird that this wasn’t mentioned anywhere in the manual so I decided to look at the old one again. Just like the rivets in the intermediate ribs, it turns out there is a difference here too. The old manual calls this out as expected and tells you to trim the skin back flush with the outside of the rib. That made way more sense and it was good to see this called out explicitly.
With the two most outboard skins in place and cleco’d along the top row, I put the leading edge skin clamps on the most outboard skin section and the velcro straps (that help get the clamps on) on the section I was trying to trim. This enabled me to see more closely where the skin would fall in relation to the nose rib since it wouldn’t necessarily be square (and I didn’t want to trim too much). I measured over from the edge of the skin to the widest spot on the nose rib at several points. I then took the smallest of these measurements and gave myself another 1/8”-1/4” of margin and marked that distance in from the edge of the skin all the way from top to bottom (I set an adjustable square to this distance and rode it along the edge with a Sharpie at the end of the square’s ruler portion).
With the position marked, I removed the straps from this skin section and began trimming with a large set of sheet metal shears. This worked okay although it left some slight imperfections in the edge (this will be fine since it will be covered anyway be the next skin). At a certain point, the sheet metal and the skin itself began to get in each others way so I switched to a nibbler and finished it off. This got a bit weird, ergonomically, as well but worked alright.
With that done, I cleaned up the edge with a sanding drum on a Dremel and also cleaned up the bad holes from the previous work session to make sure there were no sharp edges or corners.