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GO TO Protek Performance THE RV-7 AIRCRAFT BUILDING THE KIT e-mail: robert@protekperformance.com
OTHER USEFUL SITES Project started 8/15/01
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Getting the wing spar bolts to fit. Attaching the wings to the fuselage looks easy. The spar is already match drilled, the bolts are precision sized. Just get the wings in position and ram the bolts in - right? [WRONG!]. The 7/16" bolts in my kit wouldn't go through the center spar or the wing spar. I measured the bolts. They were all the correct size. The match drilled holes had been anodized after they were drilled. The anodizing process adds a couple of thousandths to the material (and the thickness of the anodize layer can vary). On my spars, the wing spar was a couple thousandths too small and the center spar was smaller yet. There was no way the bolts were going in. I used a Scotch Brite wheel on the bolts to clean off the surface imperfections and the cad coating. This brought the bolts
down to a size that allowed a zero interferance (snug, but no hammer required) fit on the wing spars. The first photo below
shows bolts before and after the Scotch Brite treatment.
The bolts still would not even start to go into the center spar. Now I needed a way to hone the center spar holes out slightly.
After trying a few things, I found the following simple solution that worked great. I attached a short strip of
emery cloth to the end of a 1/4" flex socket extension with a piece of duct tape (as shown below). This allowed me to get the
tool into the holes in a straight fashion and still use a drill to drive it. A few turns with the emery cloth and the
holes came into the same tight fit tolerance as the wing spar holes. After this, the wings (and bolts) went on without
too much of a fight. |
