Drilled ribs

September 22, 2010 – I drilled the ribs through the main and rear spars. The holes in the ribs are pre-punched, but you do have to take them to the final rivet size.

The inboard ribs, which provide support for the wingwalk, are pre-punched, but you do have to add holes. The original holes where the rib attaches to the rear spar will remain open in the final assembly. I almost messed this up. I was originally going to drill the holes from the ribs into the spar, but the instructions say to pick up the holes from the spar into the ribs. Good thing I couldn’t get the drill to go straight…

Anyway, the holes that are “X”d in this picture are the holes that will be unfilled when the wing is assembled.

While the ribs were in position, I wanted to figure out where the holes for the conduit would be located. I opted for the location called for by Vans.

The hole is 3/4″ and is located below and aft of the forward lightening hole in the ribs. After trying to visualize how to make sure I got the holes in the same place and the same orientation in every rib per wing, and much discussion with a friend, I decided to make a template out of a pizza box. (Thanks Grimaldi’s!) The template fits one way within each rib, and the ribs are mirror-image between the left- and right-hand orientations. I back-drilled from the rib into the template, then used the template to drill one of each part number of rib; the W710L, W711L, and W712L.

Then I flipped and clecoed a -R rib to the appropriate -L rib, and back-drilled that rib. I didn’t want to use the cardboard template for each rib, because eventually the hole would get wallered out. (Wallered—that’s a technical term)

Once the ribs were all piloted, I used my handy Unibit to take the holes all to 3/4″. The red line is drawn at the next size above 3/4″, so I knew to stop when I reached that point.

Now when I get the holes drilled for the right wing ribs, I can deburr them all at once and get ready to paint.

I moved the left wing main spar off the stand, and placed the right spar there, then attached the ribs and the rear spar.

I did have another senior moment doing this as well. The plans show you the left wing, and you have to make sure that you place the correct part number rib in the correct location, with the flanges pointing in the correct direction. I saw nothing about any difference between the left and right wing, so when I started to put ribs in place on the right wing, I ended up with 2 ribs that were incorrect. After a quick call to Van’s, where they NEVER make you feel stupid, I learned that a -R rib in the left wing is matched to a -L rib in the right wing, and so on.

The right wing is now clecoed together, and I made my quick Sharpie marks where the conduit holes will go.

Total Time: 3:15

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