420 hours - Prepped the left elevator for assembly

So yesterday I needed to back rivet a few less than desireable rivets that attach the elevator skin to the Trim Servo support bracket. The shop heads were just a bit uneven so I smashed them down a bit more. I also needed to debur the edges of the skin which I had not done yet.

Tonight I finished deburring the edges of the skin, and then I needed to touch up a few areas on the spar and on the trim support bracket where the loose elevator skin had managed to scrape away some material and primer from the trim support bracket. As much as I tried to prevent this from happening, I failed. The cutout for the trim tab forces you to deal with a rather unwieldy piece of aluminum that wobbles around quite a bit. The corner of the upper skin would ocassionally get lodged behind one of the attach rivets for the support bracket, or the top side H5 stiffener woudl scrape against the support bracket. I lightly sanded all the spots and sprayed a light coat of primer on them after masking up the skin just a bit to prevent overspray from getting on the exterior skin.

After the primer was dry I went ahead and clecoed all the elevator parts to the skin as a kind of precursor to the actual event when I will cleco and rivet everything together for real - probably tomorrow. I did this for several reasons:

1. It was very cold on the garage tonight and I did not want to work with cold RTV which has to be squeezed into the small areas between the trailing edge stiffeners similar to what was done with the rudder and the right elevator. This has to be done before I can close up the the skin for the last time to prevent cracking due to vibration in that area.

2. Remember that in order to prep the replacement tip ribs and spar, I had to attempt to drill and dimple the holes in the new parts with a skin that had already been match drilled and dimpled for the old parts. I had not had any of the new frame parts installed back on the skin since I had dimpled and primed everything, so I wanted to make sure that the dimples still kept everything in alignment. The tip ribs were a little bit off from the skin but they were able to be coaxed into position by inserting the clecoes along the way. Everything looks like it will fit as expected, so no nasty surprises there.

3. I still need to cleanout all the remnant primer shavings that fell off the vinyl covering that I finally removed last night from the inside of the skin. It tends to flake off the vinyl as you peel it off the aluminum, and the it contains an electrical charge that attracts all the primer shavings to the skin, so it tends to stick to everything it touches, and is somewhat difficult to remove. I'll blow this out with my air gun tomorrow just before I apply the RTV and cleco it all back together for the last time.

ONe last thing I discovered is that my clecoes do not seem to be holding the top rear spar in place very well. It seems that the countersunk holes in the top of the spar are enlargened enough so that the clecoes just do not hold it into position. this will be sandwiched by the other trim tab hinge after I get the elevator riveted together, so I am not worried about anything here. The bottom flange of the reat spar was dimpled so it holds together with the skin just fine.

SO here are a couple of pics of the underside of the left elevator clecoed together for a trial fit tonight:

I also trimmed away a little of the forward edge of the skin where it sits right next to the counterbalance skin on the outboard tip of the elevator. This skin will get rolled to close up the leading edge after all else has been completed. I noted early on that the edge of this skin that sits next to the counterbalanvce skin was actually rubbing it just a bit, whereas the same area on the right elevator had a sufficient enough gap between the two parts so that it was not a factor. So I just sanded down that edge a bit to provide enought clearance to roll it without it binding on the edge of the counter balance skin. It's all the little details that matter in the end, so as much as I really want to close it all up and smash rivets on this final empennage part, now is the time to step back, take your time, and think about all the things that you have missed along the way, or that you put off until the very last moment.

I hope to at least start riveting it all together tomorrow night. Then I can focus on final assembly of the trim tab. Almost there......