April 11, 2017
The plans show that the rear spar is to be attached to a couple of brackets on the bottom of the wing stand. I went ahead and got the wing all lined up and fastened to the jig on the top and bottom only to discover that I was holding the wing slightly askew.
I started to notice that something was wrong after I got the skin clecoed to the second rib from the root. The outboard part of that skin was off by over 1/4". After a little head scratching I took the clamps off of the rear spar and just let it hang there and everything started to line up. The more clecoes I got in the better things were aligned. The matched hole tooling is great!
After I got all four main skins clecoed in place I droped the plumb bobs over the wing like the manual shows and discovered that my wing has about 0.040" of twist in it. This is with the wing just hanging there with the skins clecoed on. I don't know how Van gets those holes so close but I am impressed. I clamped the rear spar back to the brackets to take out some of that 0.040" twist (not that it needed it but hey) and drilled.
The moral of the story is leave the rear spar unattached to the wing stand until you get the skins on, then take a measurement of the twist, adjust, clamp and drill.
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