Left Elevator Counterbalance Skin

July 13, 2010

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A short half hour tonight. First thing was to grab the primed end ribs and get them clecoed to the left elevator spar. No problems there.

Looks good. Ready to rivet (but not tonight).

Next, I need to get the counterbalance skin taken care of (must be riveted to the skin before the skin can be riveted to the skeleton).

You can see I clecoed it in place and drew a line where the two overlap; I'll use this as my primer line.

Then, I realized I’m going to have a hard time deburring, dimpling, and scuffing with the blue vinyl on. [sigh] Off with the vinyl, re-cleco, redraw my line, then back off to deburr, dimple, and scuff.

After dimpling with tank dies where the skin sits under another dimple, and regular #40 dies where it doesn't.

While I had the #6 dimple die out (I’m attaching all fairings with screws for now), I moved over to the elevator skin and dimpled there, too.

Make sure you drill all holes that need to be dimpled with the #6 dies to #28 drill. This is slightly larger than the #30 you are used to.

Again (for the search engines), the correct drill bit size for a #6 screw and #6 dimple die is #28. Ask me what happens when you dimple a hole that isn’t drilled to the right size. (Hint: the same thing that happens when you overdimple using something other than a dimple die because you are too cheap to buy a #10 die…see below…)

Okay, back to the counterbalance skin.

These are dimpled to #8 (I don't have a #10 dimple die). last time, I used a punch set (with a little rounded lip on it) to enlarge the dimples to the equivalent of #10 dimple die.

Let’s countersink the counterweight as a female dimple die.

Looks good.

Uh oh. I went a little far with my makeshift die. I stared at this for approximately 0.0000001 seconds before realizing I had to scrap the part.

See the ginormous cracks? Yeah. Not good.

A closeup of the other one. Oops.

So, the reordered part count is up to 2.

I’m not worried, I have some other stuff I can be doing while I wait for a replacement counterbalance skin (E-713, $8.85) from Van’s. Also, I immediately put in my order with Avery for a #10 dimple die (along with some clecos, an edge roller tool, and some more drill bits).

USE THE RIGHT TOOL FOR THE JOB, ANDREW!

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Trim Tab Fitting

July 1, 2010

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Okay. Today was a pretty productive day. I had taken everything apart, then realized I still had some more fitting to do on the tab, so I put it all back together again. Before that, though, I thought and thought about what to do about the two holes on the right side of the picture. These are for the fiberglass tips, and they are supposed to be matchdrilled later, after the counterbalance skin is installed as a lap joint underneath. How can I deburr parts that are riveted together if I drill through both? Maybe it’s not a big deal, but I decided to drill them to #30 now (for #6 screws).

Two holes the right before drilling...

...and after.

Then, I was thinking ahead about the safety wire trick you have to do with the hinge pin. Why not drill that now, so I can deburr before priming?

I drilled this just larger than 0.060, which is one of the biggest safety wire sizes.

Next, time to deburr and dimple the left elevator spar.

Me dimpling.

And after everything was dimpled, a nice picture down the spar of my blurry recycling bin, golf clubs, and motorcycle jack. (No motorcycle anymore, but the jack comes in handy to lift the corner of a car when a tire needs to be taken off for one reason or another.)

Spar! (I'm tired, so we are down to one word captions for the day.)

Another shot of the same.

Dimple! (Wouldn't it be annoying if I everything I wrote ended in an exclamation mark?!)

After edge finishing the two hinge reinforcement plates, I shot them with primer.

Primed!

Then, my attention turned back to the tab.  I’ve clecoed the elevator half of the tab hinge back in, and on the right you can see my drilled riblet!

Drilled riblet! (Okay, I've had enough of the exclamation points.....!)

Here’s a better picture. I basically drew a line perpendicular to the hinge line up from one of the holes along the trim spar, then spaced them at 1.5 and 3 inches. That spaced everything evenly, and gave me plenty of edge distance all around.

Don't look at my edges, they aren't finished yet, but you get the idea.

Then, I stuck the tab on and inserted the hinge.

As some would say, "Easy Peasy."

Other direction, just for kicks (not as much deflection due to cleco interference, but again, you get the idea).

Because I bought a longer section of hinge to replace my bad first attempt, my hinge pin was long enough to actually fit (Van’s says they will send you the real one (because it needs to be longer than 18″) in the finish kit.

I got to bending.

After more bending, I ended up with something like this.

Ooh, isn't that pretty! The safety wire hole I drilled earlier is in the middle there, and will allow me to safety wire this hinge pin to the spar so it won't COME OUT IN FLIGHT!

Then, I figured out how to do video. They speak for themselves, but keep in mind that while my gap is intentionally small, I still need to edge finish, which will open them up.

Another video, this time a little closer. You can see I am pushing and pulling left and right to make sure there is no interference even with the small amount of play in the hinge. I think I am okay, but this will probably open up a little after edge-finishing.

Two hours of late-night-hinge-pin-bending bliss.

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