Right Tank Stiffener Prep

May 30, 2011

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So, among other horrible things that happened to me today (leaky toilet, Sopranos DVD that kept skipping, ground turkey burgers, which were delicious, except it was actually chicken), and dogs that are freaking out at the neighborhood fireworks, I managed to drop my ONLY set of cleco pliers behind my workbenches.

“But Andrew, you have both your workbenches on wheels,” you say?

Yes, except I still have the spar box, and it’s lengthwise under both workbenches, so I really can’t move either.

After a few minutes of maneuvering, I gathered up a few things I found under the workbenches.

I was wondering where my first-aid kit went.

Anyway, I spent about 30 minutes at the scotchbrite wheel edge-finishing my stiffeners.

After that, I got them clecoed into the skins (yes, I know I’m not doing them the same way as the elevators, I don’t think I need to drill them into wood this time).

I labeled them before continuing so I could get them back to the same spot when ready for final assembly.

Here, you can see 6A (aft) and 6F (forward).

5A anf 5F.

1A and 1F. I only show these because Van's cautions everyone to have enough room to the left of these stiffeners for water (contamination) to flow to the drain to the lower left. I think I've got plenty of room.

Then, I got to drilling. I went a little different route and drilled from the outside-in.

Lot's of clecos.

After drilling, I spent the last 30 minutes of my work session tonight deburring the holes, then scuffing just the bottom side (becuase that’s where the pro-seal will go), and finally dimpling the holes in the stiffeners using my tank dimple dies from Avery.

1st one done.

Wash. Rinse. Repeat.

All 12 complete.

All that’s left before actually breaking out the pro-seal is:

1) Cleaning these stiffeners up (along with the drain flange and filler cap)

2) Deburring, scuffing, dimpling, and cleaning the skin.

At that point, I can rivet the stiffeners, drain, and cap in. Then I’ll start into the ribs, but I’ll need to do a whole whole bunch of finishing on the ribs, too.

1.5 glorious hours of edge-finishing, drilling, deburirng, and dimpling.

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Riveted Rudder Trailing Edge

March 31, 2010

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Well, it’s been 3 days since I prosealed the trailing edge, so I mentally prepared myself for the dreaded riveting of the trailing edge.

Here's the trailing edge. Hopefully, the pro-seal is dry.

Next, I pulled out all of the clecos and admired how straight it looks.

Looks straight. Let's take a closer look.

Straight as an arrow. (Before riveting.)

The clecos were easy to pull out, not a lot of pro-seal on them, and there was very little remaining in the holes. The usual step here, however, is to clean them up. Here’s a before picture.

There's a little goop in there, but not much.

Here I am using a #40 in my fingers to scrape some of the pro-seal out.

This was tedious, but I want the rivets to sit nice and flush.

Here about how much came out of most of the holes.

Next up, put the rivets in the holes to prepare for backriveting.

Rivet in, ready to go.

Then tape to protect the skins.

And here’s my new backriveting plate. I wanted a nice long piece. It’s not quite as long as the trailing edge, but I didn’t have to move it around very much.

New 36" backriveting plate.

And my setup. The power tools are holding the skin flat against the table and backriveting plate.

Ready to go.

Let’s re-read the directions. HOly crap, the pro-seal gets everywhere.

I thought it was funny how I got sealant on the sealant step.

Alright, let’s start riveting. First thing, set every tenth rivet about halfway.

Okay... every tenth rivet.

Everything was going smoothly until I got to this rivet. Can you see what I missed here?

How come there is no dimple for the rivet on the right. Uh oh.

I pulled the rivet out, put my male dimple die in the hole, and gave it a good whack with the hammer.

Rivet is out, where is my #40 male dimple die?

There it is. Not bad for forgetting to dimple.

With the rivet back in. This is the shop head side, so you won't even notice. In fact, I dare you to try to find this hole when the plane is done.

Back to riveting. I followed the directions and kept riveting every tenth, then fifth, then third, etc., until they were all halfway set.

A nice halfway set shop head.

Down the line...

Verifying that things are still straight.

Yup. Straight. Although I know why the picture is blurry. Apparently I left the cap off of the MEK. Oops.

So then I flipped the rudder over, and finished up, per the directions. Except a few things started going wrong (which is why I don’t have any pictures.)

First, I must not have had the rudder down perfectly against the backriveting plate. A few of the manufactured heads were protruding from the skins. Luckily, they rivets were only half set, so most of them were able to be pushed back into their dimples and set further after flipping the rudder back to the original side and backriveting a little more.

Next, my rivet gun pressure was set too low (I thought this meant I was being careful). The gun wasn’t getting the job done before it jumped around a little and cause a couple very minute dings. A lot of my other dings have been pretty small, and these are even smaller. I doubt you would notice if I didn’t mention it, but I’m trying to capture my experiences here, so I offer it up as a lesson learned.

Finally, when they tell you to flip the rudder over to finish the half-set backriveted shop heads, I’m not sure how this is supposed to work. With the long backriveting plate, the rudder is being supported by all of the proud shop heads, so if you rivet the manufactured head side, you’ll be adding a local bow to the trailing edge. I didn’t buy this, so I stuck with the first side and got the shop heads pretty well flush. Once that was done, I finally flipped it over to make sure they were backriveted flush.

I have some pictures of the trailing edge at the end, but after I finished, I drilled out and reset the four rivets I had previously marked.

A nicely reset flush rivet. The skin got a little scuffed here. I hope this polishes out. (Although I am now thinking paint for the rudder.)

Here’s me drilling out  the lower nutplate mounting rivets. Notice the missing nutplate.

First, a #40 through the middle.

Then pop the heads off with the back of the drill bit.

Then, use a #30 to finish drilling out.

AH! I broke a drill bit. At least I was wearing safety glasses.

I must have been adding a little force of my own.

Okay, now I can install the nutplate.

Here it is clecoed from the outside.

I had read people say “the -7 rivets were too short here, I had to move up to a -8.” The warning bells were going off when I originally set these; I was thinking, “these -7s fit just fine, I don’t know what all the fuss was about.”

Of course, I tried the -7 with the nutplates installed, and yes, they were too short. I had to move to a -8, too.

These are long rivets.

A very bad picture of the nutplate installed.

Nutplate installed.

Okay, back to the trailing edge. I really didn’t get a great picture of how straight it was, but it is straight. There are a couple local areas where there is some slight  back and forth, but it is within a 1/32″ and it’s over the course of 4 or 5 inches. You won’t see it unless you scope down the edge, which I’m probably not going to let you do if you come near my plane. Just kidding.

Trailing edge picture.

All in all, an hour and a half today. 56 rivets on the trailing edge. 4 rivets drilled out elsewhere (but already counted in the final rivet count, so I won’t recount those). I’ll try to get a better picture of the trailing edge later and post it here. (The trailing edge picture at the beginning of this post is a good angle and focal length, I’ll try that one again.)

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Rudder Counterbalance and Tip Rib

March 29, 2010

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I didn’t have a very good night in the shop tonight, mainly because I ended up not being able to use the castle nuts on the counterbalance. Read on.

Here's my large order from ACS. Lots of stuff here.

One thing I noticed was that the bolts ACS sent me were not the same size as the bolts that vans sent me. I need to look into this before using any of them. It might be something obvious, but I need to research this a little.

While I was packing stuff away, I found this bearing in my hardware box. Notice anything funny? Like the NUTPLATE THAT IS SUPPOSE TO BE INSTALLED ON THE RUDDER?


But hey, those are the two rivets that didn’t give me any trouble before, so maybe they’ll be easy to drill out and replace. (Yeah, right.)

Uh oh, spaghetti-O.

Anyway, after much fiddling around with castle nuts, I re-read AC 43-13 and decided these locking nuts would be sufficient for the very permanent installation of the counterweight.

Counterweight installed. Looks like a lot of threads left over, but I double-checked, and it's right.

Before installing the tip rib, I snagged a picture of the RTV I installed on the last rivet of each stiffener set.

Looks weird because of the reflections, but you get the idea.

Another shot, just for fun.

I'm ready to install the tip rib now.

After squeezing 30 of the easy to reach rivets, I snagged this picture of the top of the rudder.

Tip rib mostly in.

Then, out of order from the manual (supposed to do the blind rivets first), I pulled the LP4-3’s out and got those in.

First one...

All done.

I still have some things to do on the rudder:

  • Let the pro-seal dry and rivet the trailing edge.
  • drill out rivets and install missing nutplate.
  • Drill out bad skin rivets (2, I think.)
  • Tips

But, I’m getting close to another dog picture, which is always good.

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More Trailing Edge Work

March 28, 2010

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After last night’s bad fitting trailing edge, I decided to mark where the dimples weren’t sitting properly, and enlarge the countersink ever so slightly.

The problem is that if you make the countersink large enough to accept the dimple perfectly, you create a knife-edge on the wedge. I guess that is why they have you use the aluminum as a drill guide for the countersink bit. After deburring the few knife edges that I got, it ended up working pretty well, but some of the holes are enlarged a little. With the pro-seal and the double-flush rivets, I am not too worried, but it still bugged me a little. It appears other builders have run into this issue as well.

Another shot of the not so good trailing edge before enlarging the countersinks.

Before I thought I would be able to tackle the rest of the trailing edge today, I got some of the “not-reachable-with-the-squeezer” rivets. here’s a shot of some shop heads for the counterbalance skin to skin rivets.

Decent shop heads.

I also finished up the rivets for the counterbalance rib.

More shop heads.

Then, I installed and removed the counterbalance enough to be able to file away some weight so the lead cleared the shop heads of the interfering rivets.

Nice tight fit today.

Here's the counterbalance. The best file for this left big cutouts, so don't judge me for these.

I also finished dimpling the tip rib and got it edge-finished, cleaned, and primed.

Waiting for primer to dry is like watching a pot of water boil. I can't complain though. It's dry to the touch in about 15 minutes.

Even though that was plenty of work for the day, I decided to tackle the trailing edge. I had everything I needed (Lowe’s didn’t have any RTV, but then I remembered I had some at home from my motorcycle habit, so I was in luck).

Here's me attempting to design a way to keep the trailing edges apart. This sucked, and I ended up using scrap 2x4 in between the stiffeners.

Here’s my tools. RTV, MEK, gloves (I used about 8 pairs) and the tank sealant.


Don the gloves, and get ready to mix. I had to read the directions about 15 times before I understood. The hardener (I think) is in the tube part of the plunger. You stick the black piece (behind the big tube) into the hole in the plunger, and as you push the plunger from the bottom to the top, you push the black part so the hardener in the plunger is expelled into the larger tube. Confused yet?

Ready to mix. (I've already cleaned all of the parts.

After pushing the black piece (back on the table now) up to start the mixing process, you twist the plunger head while moving up and down, which starts to mix.

This is after about 75 strokes, which is what the directions say you have to do. I had to keep going. (I may have been doing something wrong, I don't know.) I kept going after this to get a more uniform "black death" color.

Then you unscrew the plunger shaft and screw in the nozzle. Okay, where is my caulking gun? I don’t have a caulking gun. OH MY GOD I FORGOT A CAULKING GUN.

Here it is fully mixed.

That’s okay, I just stuck the handle of a large screwdriver down the tube and it worked great.

Here's one side, ready to be spread out. I put a dab between each hole, and then used a scrap piece of aluminum to spread it out nice and evenly.

Another shot. This seemed to be an appropriate amount of sealer.

After that step, things started getting messy, and I had to change gloves a lot (it gets everywhere), so I stopped taking pictures. After I got both sides covered, I laid it into the scuffed and cleaned trailing edge area of the skin.

Look how good that looks. (Also, you can see my 2x4 spacers.)

Another shot.

Of course, I did a marvelous job putting a perfectly penny sized glob of RTV on the last (aft rivet) of the stiffeners before I removed the wood spacers and closed up. (The wood spacer near the bottom of the rudder was a pain in my ass. I lifted up the trailing edge a little with the top skin, so it stopped squeezing the block, and of course the block slid down toward the front of the rudder. Of course now I can’t let go, but I’m too far away from the other workbench to reach all of my long-reach tools. Ever see one of those situations where a guy has one foot in a boat and one foot on the dock, and he’s stretching and stretching? That was me. Except I finally reached a BFS (big freaking screwdriver) and managed to get the block out without contaminating any tank sealant or RTV.

Here's a blurry shot of the bottom RTV glob. Glob is a technical term.

Then, I got the rudder clecoed to the angle, wiped off any excess sealant, and moved the hole thing to the top shelf of my workbench.

Storage, kind of. I'm going to leave this for a whole week while I start on the elevators.

I think it was 11 rivets.  2 hours before the trailing edge, one hour for the trailing edge. The next post is still from today, but I am tracking it in another section and in another column for total time, so it’s getting its own post.

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More Rudder Stiffeners

February 20, 2010

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After a very busy end of the work week, I managed to squeeze a couple hours of airplane time in the shop today. I started by mocking up the R-902 front spar, and drawing a black line on the left rudder skin (this is the forward bottom edge of the left skin). I’m going to draw out all of the mating surfaces on these skins, since they will have to be primed at different times (more on this later).

Forward bottom corner of the left skin. You can see the front end of the only full size stiffener.

Next, I dove into match-drilling the stiffeners and skin. Here are the first size holes drilled. I don’t want any waviness in the rudder, so I am clecoing every hole as I drill. (You can see that like everyone else, I am drilling straight into the MDF that’s on top of my workbench. This works well, and is basically per the plans.

First six holes of the stiffener to skin match-drilling process.

After I finished the first (lower) stiffener, the next one needed to be cut down to size. I made another mark on that stiffener, this time in line with the front spar line I drew earlier. Now, when I trim the stiffeners on the aft side of that line, there will be no interference with the front spar.

Getting ready to trim the second stiffener.

Then, I got in the groove, so the next picture was after a few of the stiffeners. I used my cordless for this. Not as noisy.

Lower 4 stiffeners done on the left skin.

All done with the left side. Oh yeah, it was 60° today, so I worked with the garage door open. So nice…

There's something really rewarding about getting to this point. OH MY GOD!, WHAT IS THAT MARK BETWEEN THE FIRST TWO STIFFENERS!?

A closer look…


I turns out I dropped my cleco pliers from about 8 inches right after I completed the first stiffener. Instead of immediately pulling up the stiffener to inspect the exterior skin, I guessed that it was going to be salvageable and pressed on.

To put it into context, it is just above the first "L" in "ALCLAD."

It’s not that bad, but it would be very noticeable If I polish. (Even if I paint, it is still a pretty big mark.

From the other (exterior) side. Bummer.

Anyway, I’ve heard people talking about using the back of a spoon to gently massage stuff like this out. I spent about 15 minutes gently massaging, and I ended up with this. It looks worse than the original picture, but it is pretty flush now, and I think with a little more work may even go away.

After massaging. It's good, but not great.

Anyway, after that fiasco, I laid out the right skin, marked the front spar and trailing edge wedge on the skin, and started match-drilling stiffeners. I was in such a groove that I forgot to take a picture when I had all of the stiffeners drilled and clecoed. (I didn’t forget to take a moment to admire it, I just forgot to share it with you.)

After removing most of the clecos post match-drilling.

Also, while all the stiffeners were in place, I drew lines on each side of the stiffeners so I would have a guide for devinyling.

I call it match-drawing.

After pondering my next few steps (debur, dimple, scuff, clean, prime, backrivet the stiffeners on), I decided I need to get the vinyl off for deburring.

Here's the wooden stick I use as a guide for the soldering iron.

I don’t think I’ve shown you guys my round-tipped soldering iron yet. Here you go.

Soldering iron, heating up.

After running the soldering iron down the pre-drawn lines, I get to devinyl. I say “get to” because I like this part.

Whose fingers are those?

All done with the stiffener devinyling. You can see I didn’t do all of the outlined parts, because I want to prep and prime those later. (Have to assemble the skeleton, cleco on the skin, and match drill before you can debur, dimple, prep, etc. the rest of the stuff. Also, I need to find out if people are priming the trailing edge area before using Pro-seal. I have a feeling people are just scuffing, but I’ll ask the forums to make sure.

Ready to deburr, dimple, scuff, and prime.

Next up, devinyling the left skin.

2.0 hours today. Gotta go get cleaned up for festivities tonight.

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