Right Flap Hinge Retention

January 22, 2012

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Alright, with all the excitement of getting the flap on the wing, I decided that I might as well continue with the flap hinge.

Currently, the flap hinge pin hangs out 2 feet on the inboard side of the wing, so let’s get that thing cut down to a reasonable size.

I’m following the method of cutting some hinge eyelets from the middle of the wing/flap and attaching two halves of the hinge pin in the middle. At the end of the last session, I had marked the middle eyelets.

Here's me unbending the two middle eyelst on the wing so I can cut them off.

Where's my file?

Can’t find it. I’ll have to clean those up later.

I cut the hinge pin in half and 90° bent them.

OMG, more toes!

With some careful measuring, cutting, and bending, I got one of the halves right where I wanted it.

Like a glove.

Then matched the other side to that.

Like some other builder’s, I’m going to use the hinge eyelet method of securing the hinge pins.

During this whole process, I kept thinking how easy it would be to drill a single hole in the flap brace and just safety-wire these two hinge pins in, but I couldn’t bring myself to not finish with the original plan. More later.

Two of my hinge eyelets from scrap.

The hardware I’m going to use.

I'm using the 2-lug, MS2169106 (I think that's right) and the AN507-6R6 screws.

There's a nutplate under there.

Rivets set.

The two eyelets are not countersunk or dimpled. I'll eventually need to replace this countersunk head screw with a panhead.

After getting the hinge pins secure, I checked out the outside.

Yikes. I'll definitely need to clean those up.

2.0 hours. Really? That was 2 hours? I couldn’t believe it. Maybe I fell asleep or something. I have a visitor coming this weekend, so maybe I’ll try to prep some flap parts before then so we can bang some rivets while he’s here.

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Finished Countersinking Right Spar Flanges

August 24, 2010

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Well, tonight wasn’t a long night in the shop, but it was a good night.

First of all, there was a package sitting on my doorstep when I got home from work. After the excitement for my new Cleveland Main Squeeze died down as I realized the package wasn’t from Cleveland Tools, it quickly came back when I realized it was the missing W-712-R ribs that I had been shorted (what a cruel world!) in my wing kit.

Who knew I could get so excited about wing ribs.

Drumroll please!

{Triumphant music}

Okay, Andrew. Time to settle down.

Let’s finish up this right spar flange countersinking.

From the first issue of the 2005 RVator (thanks to Brad Oliver, for the link) and to A VAF Post (again, thanks Brad), I was able to make this cute little HTML table for you.

From the first 2005 issue of the RVator (page 10):

We countersink until the top of the screw is level with the surface, then go 2 clicks deeper on the microstop. The actual outside diameter of the countersink measures .365″ to .375″.

Countersink Widths for Numbered Screws
Screw Size Width [in]
#6 <0.3125
#8 0.365-0.375

So, I broke out my trusty digital calipers, zeroed them out, and dialed in .370″ (right in the middle of 0.365″ and 0.375″).

Just for kicks, I thought I would show you how much bigger that is than a #8 screw. The larger size allows the dimpled skin to nest nicely in the countersink.

WHOSE TOES ARE THOSE!?

SOMEBODY’S TOES KEEP GETTING IN MY PICTURES!

Anyway, I proceeded with countersinking the tank skin attach holes only (the access plate attach holes are smaller.) I am following the directions here exactly, using a #30 piloted countersink (which nestles nicely in the #8 nutplate) as my guide.

I stopped and verified the countersink depth every few holes. Looking good!

About halfway done with the bottom flange.

Here’s a countersink for your viewing pleasure.

The rivet on the right doesn't look flush, but it is. I promise.

Finally, I finished with the bottom flange. (Notice the three sets of four countersinks on the right side of the picture. Those are for the access plates. They use a #40 piloted countersink and are countersunk to a width of 0.312″ (which is less than 0.3125″)).

Ta da!

Oh yeah, now I have to do the other side.

With a noticeable lack of in-process pictures, I finished the top flange also.

Ta da! (Déjà vu?)

1.0 Countersinking-filled hour tonight.

And, I’ve finished the first three paragraphs of the wing section of the manual. Score!

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Final Prep for Right Elevator

May 20, 2010

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Well, after deciding not to work out tonight (in favor of wine), I made it out to the garage pretty late for some final prep work before riveting the right elevator.

Tonight's build partner, 2004 Manyana (play on words) Crianza. A delicious tempranillo from Spain.

On with the building, you say? Fine.

One of the last real fabrication items I have left on the right elevator was enlarging the counterbalance skin dimples. To make a long story short, I don’t have #10 dimple dies, so I dimpled with #8, and then planned on using the AN507 screw head and a nut tightened down to enlarge the dimple enough for the screw to sit flush.

This did not work.

Okay, instead of waiting for a week for a $40 dimple die to arrive, let’s be creative.

Plan: matchdrill two holes in a block of wood, countersink the holes, then use a flush set to enlarge the dimples.

Here's my block of wood, later to be countersunk.

Well, I don’t really have any good pictures of my attempt, because that didn’t work either, and I was getting frustrated.

Finally, I told the girlfriend to come out and listen to me explain the problem. (I knew this would help me come up with a solution.)

Without even flinching. “Why don’t you use a bigger screw to make your dimple?”

my face = <deer in the headlights>

Of course! (Except I didn’t have a bigger countersunk crew, but it set me down the right path.)

This should work. (It's my punch set that came with my rivet gun.)

Setup recreated (I had a piece of tape on the skin to prevent marring.)

The hole on the left has been "enlarged." This worked great!

Okay, let’s move on. Next up, I needed to locally bevel the edges where the spar and tip rib are underneath the counterbalance rib (so the top skin doesn’t show the transition bulges. So I marked those, and also started thinking about how to attach these empennage tips. See the two undimpled holes to the right? Those are two (well, 4, two on top and two on bottom) tip attach points that will eventually be drilled, deburred, and dimpled. Might as well do it now so I don’t have to worry about deburring between riveted sheets.

Lining things up to wrap my head around this interface.

I flipped the pieces over and drilled them to #30.

The top two holes have been drilled and deburred, ready for dimpling.

After dimpling…this #6 screw fits pretty well. (Editorial note: I’m pretty locked in to attaching the elevator tips with screws. I know there is really no reason to take the tips off, but right now, I don’t want to commit to blind rivets.)

That #6 screw looks like it will fit pretty well.

Once the other side was done, I primed the interior (and taped off exterior) side of the counterbalance skin.

Priming. You can see the two #6 dimples at the top of the left side of the skin. (I'll do the rest later...the rest are all accessible in the future.)

While that dries…let’s devinyl!

Hooray for devinyling!

All done. (After using compressed air to blow the flaked primer off.)

Back to emp tip attachment, here are the #6 holes in the skin, dimpled the same way as the counterbalance skin.

Nice big dimples. (Whoa, I forgot to deburr that relief hole on the left there. Fixed after picture taken.)

Let’s get this thing clecoed together.

Those big dimples sit nicely in each other. Here you can see those two holes are the only holes that overlap.

Next, the manual has you rivet the following two holes (not accessible once the spar and tip ribs are in place).

Protected with tape, this rivets were set beautifully.

Without clecos, it's starting to look like an elevator.

Next, “loosely place” the counterbalance in the counterbalance skin and “partially” insert the screws.

The untrimmed (on purpose) counterweight in the counterbalance skin.

last, but not least, they have you insert the skeleton in the skin and cleco together.

Wuhoo! It really does look like an elevator!

Those screw heads are pretty flush. (They are not tight yet, so they'll sit a little better once I get them tightened down.)

A couple pictures of some of the interfaces.

Just behind the counterweight.

Trailing edge of the tip.

Inside corner of the counterbalance rib. (What's that stuff hanging from the top edge? I'll have to investigate later.)

Finally, the trailing edge of the inboard rib.

Ready to rivet!

One more shot.

1.5 hours, 4 flush rivets set.

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