Totally (Almost) Sealed Up Right Tank

July 17, 2011

Prev | Next

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.


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.


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.

Prev | Next

Right Tank Inboard Rib Work

June 5, 2011

Prev | Next

After another full weekend of housework, errands, etc., I managed to fit in some work on the right tank’s inboard rib.

First thing, I fished out some parts. Here, Vans has punched out three parts, T-407 and T-410.

Hmm...where are my snips?

I decided to pull both assemblies(?) out and get them all deburred at the same time.

Here are the two access hole doubler rings and four rib reinforcement plates after deburring.

I put two of the reinforcements and one of the rings away until needing them on the other tank.

Then, I took one of the rings, centered it over the stiffener bump on the inboard rib, and used a straightedge to find the center of the circle.

"x" marks the spot.

I know I’m not really working on the left tank right now, but  I decided that since I KNOW the circle cutter is going to be a PITA, I’ll just go ahead and do the left rib, too.

I fished out the two end ribs for the left tank and marked them so I knew which is which.

L1 and L7.

Before mounting the ribs up on the drill press, I needed to find some wood backing. How’s this tank-rib-shaped piece right here?

Pepsi should pay me for the product placement.

Whoa. That sucked. It sucked so bad, I didn’t even take any pictures. Among other things, the circle cutter 1) wouldn’t stay in one diameter, 2) shook so badly I thought my workbench was going to fall over, 3) almost killed me twice.

But, I finally managed to get a decent looking hole.

Phew, I'm glad that's over.

See? Nice hole.

Oops, looks like the hole was a little big. No worries, edge distance for the rivets is just fine.

The hole in the rib is a little big...

After some more cursing, cheating death, and general unhappiness, I managed to get a better (appropriately sized) hole on the left inboard rib.

I think I'm going to throw away the fly cutter now. Stupid piece of crap.

Okay, I’m straying from the instructions a little here. Normally, they want you to take this access cover, hold it against the rib, and use the prepunched #19 holes to drill holes in the rib. Then, hold the stiffener right aligned with those holes, and drill the nutplate attach rivet holes. Clear?

Instead, I’m going to eyeball the clocking of the access cover (so the flat part doesn’t interfere with the indentation in the rib), then just use the stiffener ring for all the drilling. (I need to order a new access cover with no holes in it because I’m using flop tubes (don’t need the small hole), which means I need to move the float sender to the second bay (don’t need the large hole).)

You can see in this picture, the stiffener ring is laid in place, and it looks like the access cover is clocked correctly.

Access cover in the foreground, stiffener ring in the background.



Dimpled the rib, and countersunk the ring.

clecoed some K1000-8 nutplates in place.

Here’s where things got frustrating. Because I wasn’t paying attention, I just started riveting the nutplates in place.

Clearly I didn't countersink enough.

Another view. Yikes.

I drilled out six nutplates (didn’t enlarge any holes in the rib or stiffener), but couldn’t get the rivets out of the nutplates. They got THROWED AWAY!

Sorry, nutplates. You are going in the trash. It's not worth my time to fix you.

Okay, more countersinking, then try again. Still not deep enough? Ugh, more countersinking again, and finally, they were deep enough.

I got frustrated, so I stopped taking pictures. Sorry.

After much cursing and angry mumbling, I got all 24 rivets in for the 12 nutplates.

I had to drill out two more rivets because they were sitting a little proud. In the end though, I’m happy with the results.

These didn't need sealant because the access cover will be sealed over them.

A shop head shot.

24 rivets, 8 drilled out. (one third!? Ugh.)

2.0 glorious hours today.

Prev | Next

Dimpled Right Tank Skin

June 4, 2011

Prev | Next

Well, Andrew went shopping today!

It’s been brutal in the shop, so I put up the electric heater I had on the bench and put in its place this new VORNADO. For such a small package, it does a pretty good job of moving air. You have to have it pointed right at yourself though.

The VORNADO. (insert ominous music here)

Also, I bought the craftsman circle cutter for the large 6″ holes I need in the fuel tank inboard ribs.

Time to cheat death.

i also picked up some 1/4″ and 3/8″ drive drill adapters. I hate having to use a ratchet all the time for bolts. Now I can use the drill.

Oh, and a 7/16″ drill bit for the inboard rib vent fitting holes. The -4 sized AN hardware requires a 7/16″ hole.

This stupid drill bit was $14. Jeesh.

Also, I bought a nice little kitchen scale. I thought about saving some bucks and going with the analog one, but I didn’t know if I would be happy not having the digital readout.

This one was about $30.

These pliers weigh 155 grams.

Okay, back to work, Andrew!

I broke out the c-frame again and loaded in my tank dimple dies. On all of the other skins, I’d been putting the male die on the bottom, putting the hole in the skin over the die, lowering the female die, and then holding it in place while I struck it with the hammer.

On these skins, I’m flipping the skin over (so the other half of the skin hangs off the front of the workbench toward the ground).

This means I have to have the female die on the bottom, and the male die on top. To avoid my figure-8 dimple from the leading edge, I removed the return spring from the c-frame so any fidgety hands won’t cause anything to move.

Here I am about halfway through with the bottom half of the right tank skin.

(Whiny voice:) My hand got really tired (the hammer is sooo heavy, sissy boy!), so I took a break.

Not sure why I weighed a cleco, but I was curious.

13 g. Hmm.

Back to work again. Here’s the bottom half of the right tank skin.

Since there are more holes on the bottom than on the top, I am more than halfway done!

A closeup of the top skin dimpled.

The hole (get it?) thing dimpled.

At this point, I had been working for 1 hour and 20 minutes, so I felt like I should find something to do for 10 minutes just so I can log 1.5 in the build log. I broke out the #8 dimple dies and dimpled the #19 holes in the outboard edge of the tank skin.

You can see the size difference between the #40 and #8 dimples (The numbered comparison is not right here. #8 screws require #19 holes, so you are comparing #40 to #19).

With a few minutes left, and a new tool just itching to be used, I broke out the 7/16″ drill bit and drilled the vent fitting hole in the inboard rib.

I’ve been following a few threads on VAF recently, and some people are really freaking about about an exact location for this. I followed Van’s directions explicitly, which say “approximate location.”

Ha. I didn’t even give myself a starting mark!

Looks good.

Then, I pulled out the -4 fittings and screwed them in, just to see what they would look like.

The plans show this pointed foward. Okay.

The VORNADO!!!!!!!!!!!!!

1.5 hours. Proseal arrives on Monday. Next week is the black death!

Prev | Next

Matchdrilled Right Tank Z-brackets

February 20, 2011

Prev | Next

Well, it’s been a little while since I was out in the garage banging away on the airplane.

I have a few things piling up on my list of things to do. Among others, I could have finished up the landing light install, moved on to the left wing rib preparation, etc., but I kind of felt like continuing on with the right wing.

Van’s says that you should do both of the (insert noun here) if you want to save time.

Well, I have time, and don’t need to rush through this.

That means, on to the fuel tanks. The first step is to start removing metal on the Z brackets that hold the tank to the front of the main spar.

Let’s see, here they are.

Labelled appropriately. I wonder why Van's underlined the label in blue...

Oh, I almost forgot! The ceremonial plans change!

(Triumphant music...)

Okay, so there is lot’s of talk about the Checkoway method and what that is, but no one really does a good job of explaining it. I’ll give it a shot, and try to give credit where credit is due.

Basically, Van’s wants you to:

  1. Install the z-brackets (after some steps to get both sides of them drilled)
  2. Cleco on the baffle (“back wall” of the tanks) to the z-brackets.
  3. Cleco the skin to the baffle, then adjust fit as necessary by elongating holes in the baffle.
  4. Remove the skin and cleco in the ribs.
  5. Cleco the skin back on.
  6. Remove the whole thing for matchdrilling off the wing.

The Checkoway method (from what I can tell, because I never actually made it to his site before he took it down…):

  1. Drill only the aft side of the z-brackets, then bolt them in place.
  2. Attach a clecoed tank into position
  3. Drill the inboard baffle-to-z-bracket holes (doing this now, instead of before, ensures the tank is perfectly aligned.)
  4. Remove the leading edge to drill the outboard baffle-to-z-bracket holes
  5. Remove skin and ribs, leaving baffle in place.
  6. Now finish baffle-to-z-bracket holes.

The Checkoway method basically has you wait until you ensure propoer tank alignment before starting to drill holes in the front flanges of the z-brackets. If you do it Vans’ way, you might misdrill a z-bracket, and it will throw off the whole tank alignment.

Anyway, many sites have kind of hinted at this stuff, but Ethan really spelled it out nicely, and I have to give him some credit.

Of course, I’m out in the garage, so iPhone saves the day.

Ooh, remind me to charge up tonight, looks like I'm a little low on electrons.

Okay, as part of this whole Checkoway method, one of the suggestions is to move the “centerline” (future drilling reference) of the z-bracket flanges  to favor the type of fastener you’ll use later.

On the inboard-most bracket, you primarily use a socket to tighten or loosen bolts from the wing root. Hence, you should move the centerline (and resulting holes) AWAY from the web for better socket access.

On the other 6 brackets, the spar attachment is from the rear spar, so there are no access issues, but the front flange needs a blind rivet, so if you move the holes CLOSER to the web (allowing for enough room for the nutplate), then the whole thing slides over and there is more room for your blind rivet puller during final tank construction steps.

(I spent an hour in the garage tonight, and most of that time was just trying to wrap my head around this idea.)

Once I had it all sorted out, I laid (layed? Emily, which one is it?) the z-brackets out and started marking them with really obvious arrows.

Right wing inboard one gets moved AWAY from the web, second one is moved CLOSER to the web.

After some really precise (HA!) line drawing. I finally used my center punch to mark a good starting point for my #12 drill. (#12, because that’s the holes size for AN3 bolts.)


Inboard bracket drilled.

Second one drilled.

After drilling the second one (actually, I checked before drilling, but didn’t snap a picture till after), I held a nutplate over the hole to make sure I didn’t get too close.

Looks good.

Then, I needed to bolt these in position to drill the other 2 (of 3) holes. I spent a few minutes removing the lower inboard right wing skin and laid (Emily!!) the brackets in position.

I love working on the airplane. Therapy for the soul.

Okay, I have my centerline and a hole. Let’s bolt them up. (I added tape and a washer for spar-protection.)

Centerline through both holes...

Everything was going fine until I got to the inboard bracket. This doubler prevented me from getting it snugged up.


So, I just moved it to the top side, knowing I’ll have to backdrill from underneath. No biggie.

See, worked great. (You can see I used sacrificial nutplates, instead of regular nuts...easier to tighten since once you get it started you don't have to hold the nut.)

Back to the outboard brackets…

I’d drill the top hole, stick an AN3 bolt in, then drill the bottom hole.

Wuhoo! I love making aluminum shavings.

After all 7 were matchdrilled. I headed inside.

Good progress today.

1 hour. It was basically 45 minutes of staring at the plans, the instructions, and other builders’ sites, then 15 minutes of marking and drilling.

With the start of the tanks, I need to start thinking about ordering some Black Death (Proseal (tank sealant). I used this stuff on the rudder, and it really wasn’t that bad. I’m just calling it Black Death to be funny…or at least conformist.)

I can’t decide if I’m going to order the quart, or a whole bunch of the smaller tubes, which are easier to work with, but more expensive.

Prev | Next