Left Wing’s Aft Spar Riveting Completed

Now that the skeleton assembly has been laid horizontally to make squeezing the rivets easier, I took some photos of the vinyl tubing being used to keep the W-1210 rib flanges tight to the rear spar while squeezing the solid rivets.

   The pneumatic squeezer along with a piece of the vinyl tubing being used to keep flanges tight to the aft spar.

Note how the piece of tubing is just a little longer than the shaft of the rivet so the tubing compresses against the parts being riveted holding them tight together before the rivet begins to compress.

Vinyl tube over the shaft of one of the rivets attaching the aft spar to the ribs … ready for the pneumatic squeezer.

Using the pneumatic squeezer to set an AN470AD4-4 rivet used to attach the aft spar onto one of the W-1210 ribs.

I had a feeling the four rivets going through the flaperon hinge bracket would be challenging to set with the pneumatic squeezer … and my suspicions were proved correct.  The top rivet was a piece of cake the bottom two rivets were difficult and the next to the top rivet proved to be a total drag and ended up being a time sucking abyss … about 40 minutes worth. I was about to throw in the towel and use a rivet gun and bucking bar but finally got the access I needed. I was trying all different combinations of yokes and rivet sets.

There were two issues; the hinge bracket was interfering with the pneumatic squeezer body along with a rivet that was already set (a part of the hinge bearing attachment) which was hitting the yoke and further preventing a good square seating on the head of the rivet. The issue was mostly resolved by using a taller rivet set on the factory head of the rivet and a thin large round set on the shop head side. Then the pneumatic squeezer piston was carefully deployed so the squeezer body would push back and clear the one previously set rivet that was in the way. Once all that occurred, alignment was close enough to being almost square to finally set the rivet.

                              One can see the primer took a little abuse while getting the second rivet from
                                    the top  down set. It was a fight, so will need to touch up the primer a tad.

The good news … all solid rivets were used to attach the aft spar to the W-1210 ribs. As previously mentioned, AN470AD4-4 rivets were used on the aft spar to rib junctions. The rivets at the inboard end of the aft spar where the doubler plate resides required AN470AD4-6 rivets and the four rivets that go through the flaperon hinge assembly and into the inboard W-1210-L rib (the ones that gave me a fight) required AN470AD4-7 rivets.

                                     The aft spar of the RV-12’s left wing riveted in place using all solid rivets.

Now that the aft portion of the left wing skeleton is completed, the assembly finally looks undeniably like a large part belonging to an airplane.