Totally (Almost) Sealed Up Right Tank

July 17, 2011

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Oh man. Today was a big day. The other day I finally got my AN470AD6-10 rivets from van’s (along with some hole-less tank access plates, you’ll see those in a minute), so it’s time to start sealing up these tanks.

Here’s a AD6-10 rivet in the outboard rib’s aft tooling hole.

A little long, eh?

After cutting it to a more reasonable (1.5 times diameter) length, I went ahead and shot this rivet in. I think I used 70 psi. Worked well.

Not terribly exciting, but I better not forget to cover this one with proseal before closing up.

Only two things left before I can close up. The two anti-hangup brackets. Here’s one, made out of some 0.025.”

With clecos...

With some blind rivets.

This one is the access plate anti-hangup bracket. I had originally thought about making these removeable with screws and nutplates, but I don’t think I’ll ever take this out, so blind rivets it is!

Nice, right?

When I couldn’t think of anything else to do before closing, I took a final picture (then stared for a few minutes just to be positive).

Almost forgot, I wiped the whole inside of the tank down as well as I could and then vacuumed everything out.

Here goes nothing…

I cleaned every mating surface I could find with MEK then mixed up some proseal and filled a few of my 30cc syringes. I put a glob of proseal over the manufactured and shop heads of the AD6- rivet I just set, then put a bead just forward of the baffle rivet holes, and on each of the flanges of the ribs. I also left 4 big globs in each of the corners.

No turning back now.

Before dropping the baffle in, I smoothed some of the beads to a single layer.

Then, instead of letting my single bead on the skin act as my baffle seal, I also smeared some onto the baffle flange, and dropped that bad boy in place.

Pretty good bead just forward of the baffle.

Now, having read about all the trouble with proud rivets on some other build sites, I decided that instead of 100% clecoing, I’d 50% cleco, but only after I’d gotten some unset rivets into some of the holes. (The rivets fill the holes better than the clecos do, if it’s jut clecos, things can get a little misaligned).

This shot is after getting everything 50% clecoed with rivets in every other hole.

Whew. I

Before getting to the skin rivets, I threw the z-brackets in place with a layer of sealant and got them blind riveted in place. (This single sentence represents about 30 minutes of checking, rechecking, aligning, etc. with the z-brackets to ABSOLUTELY be sure they are in the right orientation. My final check was that the inner and outer brackets have their aft flange pointing inboard, all others point outboard.)

After getting the AD-41H and -42H blind rivets in place.

Solid rivets on the inboard and outboard brackets/ribs.

More solid rivets.

At this point, I set all 132 rivets on the skin to baffle joint. No pictures, though. Sorry. I have one rivet that is slightly proud, but there is NO WAY IN HECK that I am going to drill it out right now. I challenge you to come find it when my airplane is flying. (Ha. All of you reading this will have forgotten by the time I’m flying.)

Okay, time for a little clean…OMG! I’m out of MEK.

Pause for an hour…run out to Home Depot….NO MEK!?…run out to Lowe’s…stop by Target…

Little MEK, meet big MEK.

Oh. Don’t try to pour some MEK from a big can into a little can even with a funnel. It will go all over your garage floor, because it slurps out of the can and you’ve been working out in the garage for HOURS and you are a little tired, your hands are a little shaky, and even though you are wearing a respirator, you are pretty sure the proseal and MEK fumes are getting to your head.

Oh, also, don’t set a full MEK can with the cap off next to your fuel tank, then move the fuel tank so the MEK can knocks over, and spills MEK on the workbench, then drips off onto the floor where you just spilled (and cleaned up) the MEK from your earlier boo boo.

ASK ME HOW I KNOW.

Okay, back to work, you slacker!

Nice shiny new tank access plate.

More proseal here.

Then after putting the access plate in place…

(Don’t accidentally drop the access plate a hole-width or so away from your target, because then you have to kind of move the plate around with proseal everywhere while you try to find one hole to line up, then stick a screw in, and find another one…ask me how I know.)

Anyway, I twirled the very bottom of the screws in some proseal, then threaded them partway in. Once partway in, I took my syringe of proseal and put a glob on one side of the screw (see the right side of the following picture). As you tighten the screw, it drags around the screw head and makes a nice little bead (see left side of the picture.)

Perfect little bead.

I

Finally, I stuck the filler cap in place and stuck that bad boy on the wing.

WUHOO! It looks like an airplane.

“So,” you ask. “Why is this ‘almost’ closed up.”

Well, I’m not sure if you saw, but I didn’t install the float sender yet. Once I get that in, I’ll head to OSH, then come back in 10 days or so and leak test. (Although why should I leak test. I already KNOW that I have NO LEAKS.) It always helps to stay positive.

11:45am to 3:45pm, then another hour between 5pm and 6pm (after the Lowe’s run). What is that? 5 hours? Oh, and 185 rivets.

SWEET. Did everyone see my new charts? How come I’m not getting any emails with inflammatory engineer jokes in them?

I need a much-deserved adult beverage.

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Posted by Andrew

Prepped and Primed Left Elevator Skin

July 11, 2010

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Well, after an exiting morning with the South Carolina Breakfast Club, I was fraught with motivation. (I don’t know if I am using “fraught” correctly…)

Next thing on my long laundry list of things to do on the left elevator is to prep the skin for riveting to the skeleton. First thing, I got out the soldering iron and pulled off some more of the blue vinyl. While I was at it, I pulled off the blue painter’s tape I had been using to protect the back-riveted stiffener rivet lines.

All that shiny aluminum really makes me happy.

Then, on to deburring. I deburred both exterior sides of the skins, and then moved on to deburring the interior of the skins. I follow very closely with my maroon scotchbrite pad to help me remember where I have deburred (you can easily tell the difference between a deburred hole and one that has yet to be deburred…I am more using the scotchbrite pad as an excuse to give my fingers a rest…it is hard spinning that drill bit over and over and over).

The background holes are #40 (3/32") and the foreground holes are #30 (1/8"). I drilled these holes to #30 now because I don't want to wait until after the skin bending (at which point I won't be able to deburr them). Also, having the holes to final size will help with the annoying pop rivets that go in them.

Next up, dimpling the skin-to-skeleton holes. I scuff the interior of the skins before dimpling, because it is easier to scuff without dimples getting in the way.

I use my masking tape trick on the male dimple die, and I get ZERO circles around the dimples. So nice.

All holes dimpled.

Time to move on to edge-finishing. This little 90° corner is a tough one, but I think this ended up nice.

Edge-finishing.

After edge-finishing, I cleaned up, wiped everything down with MEK, and primed. Fast forward 30 minutes later, and now I get to pull the vinyl out of the skins (I’m trying to remind myself constantly to not forget the RTV in the trailing edge of the elevator bend before riveting.)

I probably add some time to the project by masking all of this stuff off and priming just the contacting surfaces, but I think it looks great (no one will ever see it) and I think I'm saving weight. Maybe not, but I sleep better because I do this.

It looks so good. I love this part of a subassembly, I'm getting close to riveting!

Last, but not least for the day was to prep and prime the two outboard ribs. These fit back to back and support the counterbalance and counterbalance skin.

On the priming table after getting a light coat of self-etching primer.

3.5 hours today on the project, but I’m only logging 3.0 here. See here for the other 30 minutes.

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Posted by Andrew

Backriveted Left Elevator Stiffeners

June 1, 2010

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I wasn’t feeling well today (sore throat, could harldy swallow), but after a nice long sleep-in and a nap in the afternoon, I went out to the garage partly because I wanted to sweat out some of the demons. I didn’t take a ton of pictures, but I managed a few.

I broke out the c-frame and dimpled the skins.

First up, skin dimpling.

I did much better on the trailing edge dimples than last time (see this post).

This is the worst one, but it still looks great, and is hardly noticeable unless you are really looking for it.

After dimpling, I wiped down all of the scuffed areas with MEK to rid them of fingerprints (oils) aluminum dust, moisture, etc., and then primed.

Primed interior. Notice how I leave a lot of the blue vinyl on the skins? This helps keep weight down (although undoubtedly adds to build time while I painstakingly trace around the stiffeners with a marker and use those lines to devinyl.

Moving back to the skeleton, I mounted a one-leg 1/4″ nutplate in the forward tooling hole of the counterbalance and tip ribs. This will hold any future weight I need to balance the elevator with paint.

I used an undersized countersunk screw in the tooling hole to help locate the nutplate, then drilled one hole and clecoed from the back.

Both holes drilled, and the main hole enlarged to something a little larger than 1/4"...I can't remember...maybe 5/32"?

Next, I moved back to the spar. I have read where a few people have added a hole in the lightening hole area of the elevator control horn/spar area. The right hole is for manual trim or for the (what I’ll call “retracted”) jack screw and wiring runs for the electric trim motor. I, like others, don’t like the idea of the wires and jack screw sharing the same hole, so I drilled another hole, in which I will add a 3/8″ snap bushing.

Pilot hole eye-balled.

Crap, I didn't even get a picture of the final size hole. (I drilled it to 3/8".)

After completed the extra hole, I noticed the skin was dry. Nothing to stop me from backriveting, now.

Rivets place in, and taped to, the first stiffener row.

Same thing with the trim reinforcement area.

After backriveting the trim reinforcement. Man, this makes me happy.

The next couple rows, done.

The bottom half went smoothly. The top half now has rivets taped in place.

Where are those stiffeners?

This isn't a very exciting picture, but they are all riveted.

Here's the inside.

I love this picture. This is the trim reinforcement plate area.

So nice. (That scratch at the top is very superficial. It'll buff right out, I promise.)

Biggest lesson today was about the aft-most rivet in the stiffeners. When bending the skin out of the way to reach that rivet, everything twists out of alignment. If you start with that rivet, it is easier to make sure everything is flush than if you rivet the forward ones first. Start from the back and move forward. You will get better results.

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Posted by Andrew

Primed the rest of the Left Elevator Stiffeners

May 31, 2010

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Tonight, I moved on with the left elevator by matchdrilling the upper stiffeners.

Here are the upper left elevator stiffeners, after trimming, being matchdrilled to the skin. First, I drilled and clecoed the forwardmost hole.

The three forwardmost holes clecoed.

After finishing, I traced the stiffener outlines on the inside and outside of the skin.

These will help me devinyl later.

You can see I have already done the lower surface of the elevator (it's upside-down on the table).

And, of course, since I forgot to add RTV to the right elevator (still trying to figure out a way to get some RTV in there), I wrote a little reminder on the inside of the left elevator.

Hopefully I'll see this as I pull out the last of the blue vinyl just before assembly.

Next, devinyl along the traced lines and then deburr and scuff.

Left elevator skin interior after devinyling, deburring, and scuffing.

Next up, I deburred and scuffed the remaining stiffeners. (I don’t have any pictures, but after this, they got dimpled and then primed.)

Because the upper surface doesn't have the trim reinforcement plate, there are 4 (instead of 3) of the short stiffeners.

Next up, devinyl and deburr the outside of the skin.

Skin devinyling.

A small tip here. I decided that at the aft end of the elevator, i would leave a little blue vinyl instead of connecting the upper and lower surface bare spots. This way, If I need to rest the elevator on its trailing edge, I won't be damaging the finish on the trailing edge.

Because it was late, I couldn’t use the c-frame.

Instead, I grabbed the hand squeezers and dimpled anything I could reach.

Just for kicks, I held up the trim reinforcement plate (and cover, still covered in blue vinyl) which will be riveted underneath the skin to the right.

Here are the other sides of the upper stiffeners getting primed.

I toook these inside for a good washing with Dawn before drying them, wiping with MEK, drying some more, and then shooting with primer.

I had a few more minutes, so I started match-drilling the skeleton. Here is one of the spar reinforcement plates being drilled to the spar.

I used my 12" #30 bit due to cleco-clearance issues.

Finally, before heading in, I shot a coat of primer on the other side of the upper left elevator stiffeners.

Nighty-night.

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Posted by Andrew

Primed Right Elevator Skin

May 19, 2010

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Well, it was a short night in the shop tonight, but after almost a week without building, it was a productive hour.

All that’s remaining before riveting the right elevator together is to finish up deburring, dimpling, and priming the right elevator skin, and doing the same (as well as getting a big enough dimple for the counterbalance attach screws) in the counterbalance skin.

First thing, I grabbed an oversize drill bit and started deburring.

I still can't bring myself to buy a deburring tool. Maybe I'm being stupid. (Who got sawdust all over my right elevator skin?!)

Then, I realized that the holes on the very front edge of the skin (for the pop rivets after you bend the leading edges together) will be very difficult to deburr if I wait until after bending to matchdrill them. I decided, like on the rudder, to drill and deburr them now.

Just making sure the #30 bit is the right bit.

After drilling, this looks like it will fit the bill when I am ready to start riveting the leading edges together.

After getting all of the holes deburred, I grabbed my scotchbrite pad and got to work scuffing. I grabbed an intermediate shot so you can see what I am doing.

Scuffity-scuff scuff.

After scuffing, I cleaned everything up with MEK (because it’s harder to clean well with the dimples) and started dimpling. Here is the inboard edge of the right elevator (which is upside-down on the table) after dimpling with #40 dimple dies.

I love dimpling. Don't know why... (Whose palm prints are all over my elevator skin!?)

A before and after shot of dimpling.

Please no comments on the lack of edge finishing here. I did all the edge finishing after this step.

Like I said, after edge finishing and another wipe-down with MEK (and the requisite drying time), I put the skin up on my garbage bins and shot some primer on the interior surfaces. If you look closely, you can see where I have left the blue vinyl on the inside of the skins. That is where I don’t want any primer (weight savings) after I am done. When the skin is dry and ready for riveting, I’ll pull the vinyl out and be left with nice shiny, untouched aluminum.

I cant wait to rivet this stuff together. I am proud of this elevator.

One little hour, but good prep work for riveting soon!

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Posted by Andrew

I Love Tungsten (Started Riveting Right Elevator)

May 8, 2010

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Well, this morning, the girlfriend ran some errands, and I got my house chores done early, so I headed out to the garage to make some loud noises. Recently, I’ve been taking one component at a time from drilled through primed. It make my work sessions less boring (not a full day of deburring lots of parts, but rather one day of drilling, deburring, scuffing, dimpling, cleaning, and priming one part).

Anyway, today, it was the right elevator spar’s turn.

First, deburring. There's my oversize drill bit spun in my fingers.

Then I put a nice scuff on all sides and edges.

Scuffed and edge finished.

Then, I broke out the tank dies to do some dimpling.

I love these dies. Such high quality.

I know you guys have seen tons of dimples from me, but I still take pictures.

The male side.

And the female side. Apparently I have not edge-finished yet.

After finished dimpling, I grabbed this shot down the length of the spar.

Right elevator spar, dimpled.

I forgot to take a picture of the countersinking I had to do on the front (flanged) side of the spar. The spar needs to be countersunk to hold the flush rivets attaching the E-709 Root Rib Right. The elevator control horn fits over them.

Then, inside for cleaning and back outside to the paint booth.

One side primed.

While I was waiting for the back side of the spar to dry, I went ahead and pulled the vinyl off both sides of the E-713 counterbalance skin.

The vinyl comes off a lot more easily when it is warm out.

Then, I got the other side of the spar primed, and prepped for some riveting. I had already prepped and primed the two reinforcement plates that get riveted to the back of the spar.

There's my new tungsten bucking bar.

Here’s my setup for spar riveting.

You can't see the reinforcement plate, but those clecos are holding it on.


After 8 rivets, all I can say is…WOW. I love this tungsten bucking bar. 8 perfect rivets. With the older, and smaller, bar I was using before, things were always bouncing around, and my hand was vibrating, etc. With this bar, it is so easy to rivet. I should have bought this at the beginning of the project.

Wow, these are amazing shop heads.

Here's the other side.

I spent about 2 minutes just staring at the bar. Amazing.

I thought I would show you my grip.

8 more, also perfect.

Wuhoo, this bucking bar is great!

And, the other side of those.

I wanted to buck these, but I thought it would be better to squeeze them.

The spar to E-709 rivets.

These are the flush rivets I was talking about earlier. Of course, when the primer is only 30 minutes old, and you try to clean up some smudges with MEK, the primer will rub off. Duh.

I re-shot some primer over this right after this picture.

What a great day. I got to make loud noises, and I’m in love (sorry girlfriend) with my new tungsten bucking bar.

20 rivets in 1.5 hours. Good day.

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Posted by Andrew