<September 14, 2005>
Riveted Right Elevator... Again!
What a great day in the shop today... I finally made it over the hump of the right elevator. If you recall, I had some problems with a few rivets and when I drilled them out the holes got enlarged. After a consultation with a few other builders, I wound up making a doubler and using nuts and bolts. Anywhooo, you can read more about it below. The good news is, I feel like I am starting to get back in the groove of building. Don't know what was going on there for a few weeks, but it seemed like no matter which way I turned I ran into problems. Lots-o-pictures tonight.
Before getting to the right elevator I riveted the trim servo brackets to the cover... so far so good.
I was afraid this might happen. This is a problem I have seen on many builder's sites. The shop head on the aft rivet hits the servo and won't allow it to sit flush against the bracket. No big deal, the fix is just to put some washers between the servo and the bracket.
Here was the fix for the right elevator. It involved a doubler, two AN525 screws, two MS21042 nuts, a tiny bit of JB Weld, and some Loctite 262. We chose this screw nut combination because it is a little lighter than the standard AN bolt and lock nut. Here you can see the doubler and nuts (with the Loctite). Now, before you pistol-whip me for using nuts in a location that can't be seen or inspected, let me say that I chose this route only after consulting several experienced builders (as in multiple airplanes). I was concerned that the nuts may back off the bolts and that I would never know. My builder friends agreed that while it was a consideration, that to meet the MIL-SPEC that this hardware does, this hardware has proven it will not back out (come loose) over time, and that the combination of locking nuts and permanent Loctite makes the chances of that happening so small it isn't worth worrying about. I took there advise and ran with it... so no nasty grams!
Here you can see the head of the AN525 screws. Why AN525 screws? Because the are a little lighter than AN bolts and have a wasker built in under the head. You can see a little JB Weld oozing out from under the screw heads. I used a drop of JB Weld around the screw shank (not on the threads) because the holes were ever so slightly irregularly shaped and the JB Weld will fill that tiny void. This is also one more layer of protection from the screws coming loose.
Here is what is supposed to look like... I went ahead and riveted these parts on the left elevator. This side came out perfect... how? Simple, I didn't follow the instructions! Instead of riveting the E-704 Tip Rib and E-703 Counterbalance Rib together, I riveted the counterbalance rib to the spar first. This allowed me to flex the rib out of the way so that I could easily get these rivets with the squeezer. Only once this was done did I rivet the Tip Rib to the Counterbalance Rib.
To prepare for riveting the left elevator, and since I had so much trouble getting my pneumatic squeezer or rivet gun into this space, I borrowed a hand squeezer from a local builder. Again, as with the pneumatic squeezer, I couldn't find the right angle or yoke to allow me to reach these rivets. Here you can see an example of the alignment issues I faced. You can see that the squeezer just can't get into the tight space to get a good shot at it. It didn't matter to me, the job was already done, but I thought I would show you what I have been ranting about.
Back to the right elevator. I riveted the control horn in place... easy-peasy!
The instructions then said to rivet the Counterbalance Skin E-713 to the skin in two places (on both sides). That is pretty much exactly what the instructios said and it took me a minute or two to figure out what they were talking about. These are the rivets they want you to set now, because once the rib/spar assembly in put in place, you won't be able to reach these holes (circled). If you don't do this now, no big deal, you can just use blind rivets, but why not install solid rivets now while you can.
I then moved onto to shaping the Right Counterbalance (E-714). I marked it according to the plans, then used a 1/4" drill bit to drill through for the curved inside edge. Then after about ten minutes of work with my hacksaw, the weight was trimmed. I then used some cheap files to smooth out the cuts and soften the edges. Sometimes, having a few cheap tools is a good idea.
After putting a dab of RTV on the aft stiffener rivets (to keep them from vibrating against each other), I clecoed the rib/spar assembly in place and called it a night.