I am slogging along doing wing ribs. I find it quite relaxing and haven't gotten bored yet. There seem to be enough little challenges to prevent that. Just to prove that this is me doing the work, here is a photo taken by my wife, Carolyn:
As you can see, I working from a single car garage. I predicted it would be a challenge, and I have not been proven wrong. When a major assembly is complete, and I am currently counting wing ribs as major assemblies, it is moved to the hangar. At the point where I need to build the large fabrication table, the two table saws, and maybe the radial arm saw, will be moved to the hangar. That will create just enough room for the full size (4' X 14') fabrication table. The table itself will be built in modules. I will detail that plan in a later post. For now, I am a long way from building that table.
I have completed both the left and right #2 ribs, and the left and right #1 ribs are almost complete. The only thing that needs to be added to them are the reinforcing blocks for the wing root fairing attach brackets. Those blocks have been cause for a lot of fussing for so small a part. The Wag-Aero plans call for 10 blocks. They don't say whether that is 10 blocks total or 10 for each rib. A sketch on the plans seem to indicate 10 total. Also, the rib plan shows one block near the middle of the top capstrip, which does not jibe with the drawings and details for the top wing root fairing.
What I have found from looking at a couple of Piper built aircraft is that there is one bracket on the top of the rib just aft of the main spar, a bracket on the bottom of the rib just forward of the main spar (which will not require a reinforcing block because the nose block is there) and nine brackets spaced more or less evenly aft of the main spar along the bottom of the rib. Which, according to my old fashion math, totals 10 reinforcing blocks, mostly along the bottom of the rib, for each wing.
The bracket itself is a study in confusion. The Wag-Aero drawings show a simple aluminum bracket to be attached to the rib by wood screws. It appears that the intention is for the wing root fairing to be secured to the bracket with sheet metal screws.
Piper seems to have been somewhat confused, as well. There are two drawings in the set for the PA-15 for the wing root fairing attach bracket. One is number 11455 and the other 11463. They were created within a few days of each other in 1947. 11463 was drawn by LEK on 9/30 and checked by JCB on 10/3. 11455 was drawn by RJC on 9/29 and checked by LEK on 10/6. Further piquing my curiosity is the fact that 11463 is drawn incorrectly, with the long leg only 1-3/8" instead of the specified 1-1/2". They both show revisions, though not the same revisions, up to 1957, when the revisions for 11463 cease. The revisions for 11455 continue to 1963. The big difference between the two is that 11455 shows a rivnut to receive the fairing attach screw. Much preferable to a sheet metal screw as the lower wing root fairing will need to be removed for each annual inspection. It appears that the rivnut was added in 1950. My guess, as a response to reports of stripped out sheet metal screws.
Plating the #1 ribs resulted in some education. Plating the first one was relatively easy. I simply built a full rib, removed it from the jig after gluing up the gussets, flipped it over and attached the plating. The second rib was much more of an adventure. I won't detail the process (because I won't do it that way again), but it was a scramble. During the scramble I needed to fasten down part of the plate RIGHT NOW or have a problem. I grabbed the nearest staple gun (I have three and have been using them as weights) and plugged in a couple of staples. This particular gun had heavier duty staples than the gun I had attempted to use before. All the literature recommends using regular weight (like you would use in your office stapler) staples and that didn't work well for me. The heavier staples worked great.
So I have abandoned using the big bolts as gluing weights and have returned to staples.
Today I intend to pull the staples from the first #3 rib, which is complete except for that step, and glue up the gussets on my first aileron rib (#4). When those are done and moved off the jig and up to the hangar, I will work on the wing root fairing attach bracket reinforcing blocks.
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