Got started out in the garage at an actual decent hour today, unlike yesterday. It was a beautiful day outside, perfect for just opening the garage door and enjoying the perfect temperature. I timed the arrival of the wings pretty well…just in time for spring!
The first order of business was to prepare the rear spar webs, the inboard reinforcement forks and plates, and the reinforcement plates for the aileron hinges. The forks and plates are beefy pieces of aluminum stock, and the edges on them needs quite a bit of work; lots of tooling marks and bumps and such. I probably spent a solid 45 minutes just on the edges of those pieces. The insides of the forks presented a special challenge, since they’re not accessible with the bench grinder wheel. I was able to get most of the length of those with a smaller scotchbrite wheel in the die grinder, but even that wheel was too large to get all the way into the fork. For that part, I settled for working with various files and finishing things off with some emery cloth to get a good finish.
A look at the edge of a finished plate (top) and one that hasn’t been touched yet (bottom):
With all that edge finishing done, it’s time to drill the aileron hinge reinforcements to the spar. For whatever reason, these don’t come predrilled at all, so they have to be clamped in place and drilled using the holes in the spar web as a guide. For the outboard plate, alignment is easy; it just lines up with the end of the spar. The inboard plate is located 50 3/4″ from the outboard end. In order to be extra-careful here, I marked the rivet holes from the spar and removed the reinforcement to make sure edge distance was going to be OK before committing to drilling.
The drilling is pretty straightforward, but there’s another required modification to the inboard plates. These plates cover a hole in the spar web that the aileron pushrods will pass through later, so a matching hole needs to be cut in the plates. I traced the outline of the hole while I had the plate clecoed in place for drilling, then used a Unibit to make a nice-size starting hole in each plate, and then went to work with the Dremel and a cutting bit to finish the holes off. I then cleaned the holes up using a round file and finished them off with emery cloth for a nice smooth finish.
Hole outline (the plate on the left is an outboard unit, which requires no more work):
Getting close, time to turn the Dremel down so I can control it better:
And the finished pushrod holes:
Next up, the reinforcement forks and plates are clecoed in place and final-drilled:
With all that done, I sat back in my deburring chair and went to work on all those holes I’d just drilled. While doing this, I realized I’d forgotten some holes in the aileron reinforcements; since they nest into the spar channel flange, the reinforcement flange needs to be drilled there as well. So I got to cleco them in place again, drill some more holes, and then deburr those holes. FInally, I went ahead and dimpled the holes on the spar channel flange where it mated with the reinforcement plates. I also dimpled the flange holes by the reinforcement fork; once the fork is riveted in place, these will be difficult to get to, so it’s better to take care of this now.
That got these pieces mostly ready for cleaning and priming. I still need to dimple the flanges of the reinforcement plates and do some countersinking as well. Particularly on the outboard plates, some of these holes need flush rivets; it’s up to me to figure out which ones and countersink or dimple those holes before assembly. That will have to wait until tomorrow night; I was surprisingly tired by early evening, and I need to do some prep for work tomorrow…so I decided it was time to retire inside for the day.