3.2 Hours -
This morning, I finished assembling all of the z-brackets, or at least all but the three that I screwed up. Once they were all assembled, I started to install them on the spar. However, I quickly realized that the socket driver I had was way too big for the cramped quarters of the wing. I made a mental note to buy a smaller ratchet.
After a quick trip to the gym and Lowe’s, I got back to work on the z-brackets. With a new, smaller ratchet driver in hand, it was much easier to install the bolts for the z-brackets. Once all of the inboard brackets were installed, I turned my attention to the outboard brackets.
The outboard brackets are installed using nutplates attached to the spar rather than the bracket itself. The spar is pre-punched for these nutplates, but they still have to be countersunk for the rivets. I was able to countersink all the holes, except for two on each spar, with my microstop countersink attached to an electric drill motor. I’ve decided that the slower speed of the electric drill makes much nicer countersinks than the air drill. The other two holes (the top- and bottom-most holes on each spar) had to be hand countersunk with my deburr tool because there wasn’t enough room for the countersink cage.
The nutplates for the inboard z-brackets attach to the spar instead of the bracket. I countersunk the forward surface of the spar using a microstop countersink on an electric drill.
Once the countersinks were finished, I riveted the nutplates to the spar. It took me awhile to figure out how best to do this, but I ended up back-riveting them from below. Instead of a back rivet plate, I just held a bucking bar on the factory head. It was a really tight fit to get the rivet gun and my hand inside the wing since this is done in the wing walk section where the ribs are very close together. My riveting wasn’t too pretty, but it will get the job done since the nutplate and bolt are structural, not the rivet. If I build a second plane, I’ll install the inboard z-brackets before installing the ribs.
The nutplates are riveted to the spar. I back riveted them from below.
All the z-brackets are bolted to the left spar.
With all the z-brackets installed, I moved my attention to the fuel tank ribs. I’ve been deburring ribs in batches because I really hate deburring ribs. So, before I can proceed, it’s time to take care of the tank ribs. I started by deburring the edges of all the left tank ribs with my Scotchbrite wheel on the drill press. After seven ribs were done, I had enough and decided it was time to head inside to the air conditioning.
The left tank ribs have been deburred on the Scotchbrite wheel, but there is still a lot of work to do on them. Notice all the dust...they've been sitting around for awhile.
