(page 13-2) Wings continued

After priming the mating surfaces on the 20 rib-attach angles, said angles had to be riveted to the spar webs using pulled rivets (thankfully).  This would involve my favorite tool, the pneumatic puller. Problem was, the

rivets are very close to the angle flange, necessitating use of either the little wedges which were constructed as the very first step in the entire build (can't find them) or the tool shown in the first photo (wedge with a handle).  Using the wedge tool and flexing the angle a bit allowed all the rivets to be pulled without reverting to the manual riveter.

Since the rivets had to pass through the spar web as well as the angle itself (and sometimes another angle on the opposite side), hole alignment was an issue.  The custom hole-alignment tool (Vice-grips holding a 1/8th-inch drift whose tip I tapered) solved the problem, as usual. I prefer this to using a reamer or #30 bit, and I've found very few cases where this wouldn't work.

The next step involved machine countersinking 120 degrees all of the #30 holes on the slanted flanges of the stub spars.  Even though a countersink cage is used for this, I've always found it hard to get exactly the same depth on countersinks.   Van's suggests drilling a 1/4-inch hole in a scrap piece of aluminum and using this as a quick gauge for the larger diameter of the

taper, which I did.  It's still hard to make them identical.  Apparently, dimples in the leading edges of the wing skins fit into the countersunk holes.

The stub-spar doubler plates get riveted to the stub spar webs with 1/8th-inch solid rivets, requiring use of my Main Squeeze and jeopardizing my recently repaired rotator cuff.  Hole alignment again required a fair amount of effort.  The holes with clecos get left open at this point.

The six #40 holes within the inboard rounded portion of the stub spars get countersunk 100 degrees on both faces for "double flush" solid rivets.  Double flush, of course, means the countersunk rivet is squeezed using a flat set until the shop head is flush with the surface of the aluminum, leaving nothing protruding on either side.

The semester is officially over.  All grades have been turned in and, following last Saturday's commencement ceremony, a fresh batch of mechanical engineers has been released into the wild.  Theoretically, I should now have plenty of time to work on the airplane.  The antique car is, as usual, taking part of my time.  The engine for it is going together well as I continue to hemorrhage money.  Should be on the dyno within the week.