Started working on the Elevator Tab

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After some more days of not doing anything, I managed to make it out to the Pilots N Paws fly-in today. It was good motivation for working on the airplane.

Anyway, I’ve drilled the left elevator skin to the skeleton, and the next step is really to take everything apart, deburr, dimple, countersink, prep, prime and assemble…

BUT…

I have some things that need to be done first. Mostly, the directions want you to bend the elevator tab “ears.” Well, I don’t think I want to go the bent route. Here’s what I am worried about. I don’t think anyone would really notice, but I don’t love the way this looks.

Bent trim tab ears. I think I'm going to cut mine off and make little ribs.

I think with some work, I could make them look like this, but given how finished these surfaces are, I don’t know if they started as bent ears or riblets.

WHOA! This is awesome. This guy really finished this joint up nicely. Everybody be jealous.

Finally, I found a really nice riblets version. I like this, and this is what I am going to be aiming for (although I am going to try to use solid rivets.

Great finish on the cut-instead-of-bend tab ears. I'm going to strive to make mine like this.

Anyway, I also think cutting the ears off (not bent down in the way) will allow me to use solid rivets in the blind-rivet locations on the top and bottom of the elevator (outboard trim spar rivets). We’ll see.

First step is to get the skeleton re-clecoed in the skin.

The trim spar and the inboard rib.

Van’s wants you to countersink either piece for flush rivets (not for any real flush reason…I think they need to be #40 size holes, and they don’t give you any universal head AN470AD3 rivets). Anyway, per standard practice, I dimpled both.

Dimpled instead of countersunk.

After clecoing together the skin, I am ready to start the headscratching with the tab. Let’s find the tab spar.

There it is.

Let’s go ahead and cut off these tabs. After careful measuring and marking, I’m ready to put blade to metal.

Inboard side. I'm nervous about chopping these off.

Outboard. (see how I lined up the line parallel to the flat portion near the top and to the left of the relief hole near the bottom? This doesn't work. Read on to find out why.

After a quick snip (not too close to my final line) I removed the vinyl from the interior of the skin in preparation for using a file and scotchbrite pad to clean everything up.

Devinling before finishing those cuts.

After working carefully with a file and edge finisher…

Looks good.

Before I really finalize things, I’d like to get my tab placement set up. First, I tried using this extra piece of rudder stiffener.

It worked okay, but I later switched to something a little longer.

After some moving around and fiddling, I re-read the directions, which tell you to bend the elevator ears down along a bend line that is perpendicular to the hinge line. Well, that means that the cut lines should be perpendicular, too. Of course, like I mentioned before, my original outboard line wasn’t perpendicular. All that file work for nothing.

I drew new lines (one on top of the other, ignoring the needed clearance).

Drawing new, perpendicular lines.

Then, I made a “pretty close” cut with the snips. I’ll need to really clean this up, as well as move the line to the left for clearance purposes (I’ll wait until the hinges are drilled to really see what I need. (The instructions call for 3/32″, but that is for the blind rivet head clearance that I won’t have to worry about.)

Pretty close, but still needs trimming and finishing.

Next, I moved back to the tab. Here’s my new line.

I'm bummed because the upper part of the tab, factory provided, is not perpendicular to the hinge line. That means there will be a slight angle there. Bummer.

After getting those refinished, I got the tab mocked up. I kind of worked backward. I want to use the inboard edge and the trailing edge to get placement, then verify I have adequate clearance on the outboard edge and between the tab and elevator for the hinge (there are some hinge dimensions on the plans). I think I’ll have plenty of room.

This looks good, but I'll have to keep trimming that outboard edge.

Here's a closeup. You can see the edge near the top of the tab is angled a little left. This is how it comes from the factory. The marker line and aft portion of the tab are both perfectly perpendicular to the hinge line (line through the center of the rivet holes).

Later this week, I’ll work on getting this perfect, then tackling the riblets that need to be constructed before doing any more work with finishing the skin.

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