McRiblets

I spent a few hours today finishing the bend to the new elevator trim tab skins and fabricating small ribs (riblets) to close out the ends of the trim tabs.

I think they came out really well. The first one I did came out fine, but was a bit of a test on exactly where to bend on my marked line to get the proper part width/flange length. I then was able to bang out the 4 riblets that I needed to make. Two outboard and two inboard riblets. The outboard riblets somewhat interfere with trim tab horns, so I made the flanges a bit longer to share holes and ensure proper edge distance.

I took the following pictures to document the process.

Started with a wooden wedge (oak) that I had previously made when trying to bend the tabs per the plans as a template against scrap trim tab skins.
Traced the outline of the wedge, marked the top and bottom cuts, and make a 20/32″ outer mark for the flange width.
Cut along the outer lines with snips.
Marking the position of the spar on the bottom skin and transposing that line to the riblet
Using a punch to locate the hole to be drilled
Drill a hole to serve as the relief for the flange separation
Snip out the metal on the tangent lines of the circle creating a separate flange piece that can be bend in more to accommodate the extra layer of metal of the spar.
Bend along the marked lines with a hand seamer.
First flange bent
Spar flange bent
Done!
Pretty good fit!
All 4 riblets completed. I used a 20/32″ flange for the inboards and a 28/32″ flange for the outboards to allow for hole edge clearance.
Marking out new holes that I will drill in the skins to rivet the riblets in place. 3 new holes will be added between the notches in the skin.

All-in-all, I’m very happy with how they came out. These were really the first true part that I’ve had to fabricate from scratch on my own. It really wasn’t as hard as I had anticipated, and it’s satisfying to see it come together. I can tell already that I’ll be very happy with how this turns out compared to my barely acceptable bending of the tabs.

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2 thoughts on “McRiblets

  1. William R Harr November 7, 2016 / 1:31 am

    They look great, Adam! Way to go – keep it up! 😀

    Like

  2. Gary November 10, 2016 / 10:24 am

    Looking good, Adam. Fun to watch your progress.

    Like

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