Rivet count: 1833 + 71 new = 1904
I left off getting ready to assemble the trim tab. Well, I’m still there! Two issues: I wanted to mix just one batch of pro-seal to glue this up and I didn’t have a #33 bit to final drill the close out tabs and I didn’t have a dimple die to dimple for flush pull rivets. Sigh.
I did get some work done however before putting the trim tab aside. I riveted the bottom trim tab skin and the trim tab horns to the front spar. I primed underneath the horns (a bit of overspray on the blue plastic will disappear when I do final prep). I did cleco the trailing edge wedge into place to see how much play I had left to see if I can set the trailing edge and then dimple the close outs. One builder suggested final drilling the close out tabs last to help eliminate twist. I’m not sure how to do that (drilling is easy, but dimpling would be tough).
With the trim tab on the bench, I started assembling the left and right elevators. I had the parts sorted onto my left and right bench to help keep it straight in my head which parts went with which elevator. I also cleco first the left side and then the right before I go crazy with the riveting in case I did a dyslexic number on the parts.
The first step is to rivet a small gusset onto the left root rib (where it intersects the rear spar). I had the part and direction marked, so it was pretty easy to drop a couple of 1/8″ rivets in there.
Then the two pairs of tip ribs get riveted together. Two rivets are 426 flush rivets to accommodate the lead counterweights, but the rest are domed. I put the domes on the visible interior face since this will be more visible. It was actually a bit of a tough squeeze to get the rivets there done. There are two facing flanges (one for each part of the tip rib), so you can’t quite get the yoke over both with the rivet sets in place. I solved it by sliding the squeezer over the flanges and then inserting the rivet set. Kept it clecoed to keep the two parts aligned and tight. Final product seems OK.
The tip and root ribs then get riveted to the main spar. The root ribs are a bit tough since they bend inward. The left one wasn’t to hard (I used my longeron yoke), but I could not get the right one to set. I switched to my 4″ thin nose yoke which fit in nicely. You need to watch the rivet call outs in the plans. The flange on the tip rib requires a 3/32″, not a 1/8″ rivet.
The front spar gets four doubler plates each of which hold a big K1000-6 (not a K1000-06) nut plate. I hadn’t prepped these parts, but they were very easy to prepare. A couple quick passes with a file, a pass through the Scotchbrite wheel, and a quick coat of primer and it was done. Not as easy was finding the K1000-6 nut plates. I really bugged me as I could not find it in any of the bags of nut plates. If you recall, I had the problem before…. With the same part! That’s because the nut plates (really huge ones) are in the empennage hinge parts bag. Sigh!
I had foolishly promised my wife that I wouldn’t work too late tonight, so I just got the next step started. The tip rib skins wrap around the counter balance and eventually fit under the skins. I eased the edges beneath where the front spar and tip rib stack on top of each other so that the tip rib skin wouldn’t show a ding where it bend over the edge (and then added a quick shot of primer to cover the bare metal). The top skin goes on top of this whole stack too! So I used a file to ease these skins as well (and primed). Hopefully, I’ll get a nice smooth transition when all is said and done.
So, now at last, the elevators are re-emerging from the pile of parts:
Next up: The elevator horns get added to the front spar, the rib halves get riveted to the rear spar, and then the skins start getting back riveted to the rib halves. The trim tab will wait until I do the pro-seal on the main elevator bodies. I did some research online and a couple people found that a #40 dimple works well for the #33 pop-rivets (though I still need a 25mm drill bit).