Rear Spars

Time: 6 Hours

Today my goal was to finish up both the left and right rear wing spars so that I could prime them tomorrow. This would allow me to prime them this weekend and have them ready to rivet next weekend. I have to be out of town to Wichita for a Bombardier safety conference. First up was to layout the all the parts for each side.

The plans have you match drill the two doubler plates to the spar.

The outboard doubler is supposed to have a row of flush rivets that tie the doubler, spar and end rib together, the plans call for countersinking here. I have read several builders sites that have dimpled instead of CS’ing. I decided to follow suite as I’m not sure about the thin material. I will just have to remember to dimple the flange if the rib.

Next up was to match drill the inboard doublers.

The center doubler also needed to have the aileron push tube hole cut in it. Once I had the holes all matched and drilled I used a sharpie to mark the area that I would need to remove.

I used my unibit to drill a couple of holes and then cleaned it up with my dremal’s small sanding drums. I then attached it back to the spar and fine tuned it with a Scotch-Brite wheel.

Once I had both the left and right sides done I cleaned up the shop a little to prep for priming. I debured all the drilled holes then hit everything with a Scotch-Brite pad. I bought a mini orbital sander from Harbor Freight and tried it here. The small pad has Velcro on it and holds a small square of Scotch-Brite pad really nice.

After the prep I cleaned everything real well with MEK and let them dry. While drying I cleaned all my tools and returned everything where they belonged. Then I hit the parts with primer. I will flip them over tomorrow and hit the other sides then.

Another great day in the Hangar!!

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