Countersinking Left Wing Skeleton

I forgone priming tonight, I’ll do that this weekend.  But, I did get some good progress on the left wing skeleton.  I completed all of the machine countersinking on the main spar, so its ready for skins!  Here’s the timelapse:

I chucked up my microstop countersink cage in my Sioux drill, and made a few test runs in the middle of the spar to be safe, and get make sure the countersink was still set correctly, and it was.  I verified by sticking a rivet in the countersink to make sure it was nice and flush.  Then I simply worked my way down the entire main spare, countersinking the holes for the leading edge skin, and the holes for the main wing skins.

Once I had all the holes countersunk, I needed to prime the now naked holes to prevent this exposed aluminum from corrosion.  I mocked up a cardboard template to keep the overspray off the pretty gold anodizing of the main spar, and sprayed some rattle can self-etching primer, doing my best to only get it in the holes.

I wanted to keep this layer pretty thin so as to not interfere with a nice smooth fit on the skin.  I think the holes are nice and covered in a protective layer now.  I also did the same on the rear spar, since I used a deburring bit to remove a small bit of metal in those dimples (per Vans instructions), and they also needed protection.

After that, it was time to clean up all the shavings, dust and debris that had collected in on the spars from sitting in the stands so long.  I grabbed the vacuum and gave the left wing a good cleaning.  It’s ready for its skins to be riveted on at this point.  I am planning on shooting primer on both leading edges this weekend, and I’ll jump over to getting both of them riveted, then do this same dimpling and countersinking work on the right wing.  This should help change up the work a little to keep it interesting.

Google Photos Link: https://photos.app.goo.gl/Z61nZUyTcHrJ1WWE8

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Hours Worked: 1.50

Dimpling Left Wing Skeleton

After resetting the time lapse camera to get a better angle. Here’s that video:

I went ahead and moved on to the next step in the plans. Vans has us remove the skins, and dimple the skeleton for the wing. So I did that, and used my squeezer to dimple the ribs. Worked great!

Vans advises that after we dimple the rear spar, we should use a deburring tool to remove a little metal so the skin fits better. So I did that on the rear spar.

One last little thing I did was to also use the deburring bit in the holes on the reinforcement plate on the leading edge, per the instructions. This makes a nicer fit to the skin, like the rear spar we just did. I did both the left and right leading edge plates since they’ll be primed soon.

That’s all I had steam for tonight. I’ll work on countersinking the holes in the main spar tomorrow, and then I’ll need to do these same steps on the right wing.

Hours Worked; 2.0

Deburring and Dimpling Right Wing Leading Edge Skin

I came down to get a little work done, and knocked out getting the left Wing leading edge dimple and a D bird all the edges of this leading edge. Now all of my leading edge parts for both wings are ready to be scuffed cleaned and primed with AKZO, Which I’ll do another session and do them both at the same time.Which I’ll do another session and do them both at the same time. That’s it for this quick session

 

Hours worked: 0.75

Deburring and Dimpling Right Wing Leading Edge

A quick session tonight. I removed the right wing leading edge, disassembled it and then began deburring and dimpling the ribs. I used my pneumatic squeezer to simple all the ribs in quick time after I got them deburred. Here’s the pile of completed parts.

Next I decided to go ahead and get the leading edge skin ready for dimpling, so I used a full soldering iron to remove strips of the blue plastic around the rivet line.

  
That’s about it for tonight’s work. The leading edge skin is ready for dimpling. Then I’ll prime both the left and right leading edge skeletons and skins in one session. I’m hoping my AKZO is still good!

Hours Worked: 0.75

Dimpling the Left Wing Leading Edge

Back to work on leading edge.  I managed to get all of the left wing leading edge parts ready for priming in tonights session.  I also captured a time lapse, and you’ll see at the end a lot of reading and standing / looking / planning.  I am not going to count that work in the total time 🙂

I started out by dimpling the ribs for the left wing leading edge using the pnematic squeezer.  Its faster and easier than using the Numatx squeezer on ribs at least.  These went pretty quick, and now they are completely ready for priming.

Once that was done, I grabbed the leading edge skin, and removed the blue plastic using a soldering iron with a dull tip.  There wasn’t many complex rivet lines on the leading edge, so it also went pretty quick

Then I opened the hole for the tie-down ring a bit.  I made this a wee-bit smaller than I needed it appears, since the tie-down ring won’t go in it nicely.  I used a step-bit to open the hole big enough to fit the tie down ring I bought from Vans a few months back.  Then I deburred the hole.

   

Now it was time to get the skin deburred and dimpled.  I used a reamer on all the holes, so I am electing to not use a deburring bit on these holes, as they are all going to be dimpled, and then scuffed for priming.  Given than reamers leave almost no burrs, and the dimples and scuffing will smooth out any burrs, I think this will be perfectly fine.  However, the skin edges and corners did need some work of course.  I used a bastard file to round the corners off, and then used that file to smooth down the bumps and ridges on the edge of the skin where it was sheered on the presses.  Followed that with a scothcbrite pad to get the edges super smooth, and the skin was ready for dimpling.  Dimpling went very easy with the DRDT-2, as you can see in the timelapse above, I got all the holes dimpled and ready for scuffing, priming and riveting.

Thats it for tonight.  Like I mentioned earlier in the post, I spent a good bit of time reading ahead in the plans, looking at the drawings and looking at my wings to get a picture in my mind whats next.  Of course, I still need to deburr and dimple the right leading edge parts, but that wont take but a couple hours of work.  Then I’ll prime all the leading edge parts in one session.

Google Photos Link: https://photos.app.goo.gl/ZfwU2ziwnDAEDrKYA

Hours Worked: 1.75

Deburring Leading Edge Ribs

 


Picking up from the last session, I spent a little time deburring the ribs for the leading edge. I had disassembled the left wing leading edge in the last session so it’s time to debur them for dimpling.



That’s all the parts I got done. I decided to spent a little time cleaning up the shop and getting ready for these next rounds of work. I’m only counting the 45 minutes spent on the ribs in the log though.

Hours Worked: 0.75

 

Leak Testing the Left Tank

Another quick update.  The left tank has been curing for about 4 days or so, and its time to do a leak test! I set it up like the right tank, by using a ballon as a presssure rupture vessel and also a pressure containment vessel.  I aired the tank up, until the balloon was inflated then let it sit for a few minutes while I studied some plans.

I also got my shipment in from Cleveland tool for the extended back riveting set and flush bucking bar for the wing skins, and a few other things.

After a little while, I noticed my balloon had deflated! OH NO! Was this a leak?  So I reinflated the tank, and grabbed some soapy water.  After a few squirts I was relieved to see that my leak was coming from the test kit itself, so I tightened up the schrader valve fitting until the bubbles went away, and let it sit a few more minutes.

I also sprayed down every rivet on the tank with that soapy water to check for leaks, and found none! So I washed the tank down with the garden hose outside, and wiped it dry, and left the balloon inflated to sit overnight so I can see if there are any tiny leaks over time.  I decided to get started on the next step: the leading edge skins.  I removed the left wing leading edge, and disassembled it, because I need to deburr and dimple the holes.

I left off here, since its deburring time.  Thats a good session for tomorrows work!

I did record a timelapse, but it doesn’t show much.  At any rate heres that video.  You’ll see me on the phone a little, checking out plans a little, and pretty much “fiddle-farting” around waiting on the leak test.

 

Hours Worked: 0.75

 

Closing Up the Left Tank

I managed to get the left tank closed up tonight!  I started out by cleaning the tanks inside really good with MEK and paper towels and made sure all the parts were in the right order and oriented.  Then I cleaned the baffle really good with MEK, as the tank and baffle were scuffed in a previous session.  Next up, I mixed two tubes of 70 grams each of sealant for the Semco gun to make swapping easier.  Then I laid a thick bead of sealant along the rivet line on the tank skin and the rear flanges of the ribs to seal the baffle in place.

I made sure to squirt a big glob in each of the four corners where the baffle will seat, then slowly slid the baffle into place.  From this point on I did not snap any more photos as I was having to work quick before the sealant set, and I was pretty covered up in this goop.  BUT….the time lapse did manage to catch the entire session which is great! Check it out below.

I clecoed the skin to the baffle at every other hole, and then clecoed on the mounting brackets. I wanted to squeeze the rivets on the skin first, so I started inserting rivets, and then squeezing them with the Numatx squeezer.  Tammy and Acacia came down to help with this part which was nice.  We worked as a team, I’d squeeze while she was inserting rivets, then I’d remove clecos and help insert rivets, then squeeze!  After that, I wanted to pull the blind rivets for the mounting brackets and rib end flanges.  Tammy twirled each blind rivet in sealant, and put them in the holes, and I’d set them with a rivet puller.  Tammy then dolloped sealant onto each of the pulled rivets heads.  All that was left was for me to do was insert the float fuel level sender in the baffle.  I laid a bead of sealant around where the sender mounts onto the baffle and Tammy smoothed it out nicely.  Then I gently inserted the sender and we screwed it down using the stainless hex screws, smearing sealant under their heads before torquing down. After this, Tammy and Acacia called it a night.   I didn’t have much left to do, except squeezing the inboard and outboard end rib rivets.  We squeeze these since that are accessible.

After all the riveting was done, I moved the tank back onto the work bench, where I dolloped on some sealant to the shop heads of the rivets, and made nice filets around the 4 corners of the baffle where it fits with the skin and ribs flanges.  I then cleaned off the sealant from the skins and any other spots on the outside of the tank.  I also grabbed the fluke multi-meter to make sure the sender’s flange was making a good electrical contact for its ground to the tank.  I checked the flange, against the skin and read 0.2 ohms, which is great!  I also measured the resistance from the terminal on the sender to the skin, and saw the proper resistance of 400 ohms for the senders position.

After that, it was tool cleanup time, and I called it a night by sitting the tank upright on some boards, against the Z-brackets.  This will keep the sealant from running down to the nose of the tank as its curing, it should all run down to the baffle and help seal it.

Google Photos Link: https://photos.app.goo.gl/R72HNP8W4PAEGbFS6

Hours Worked: 3.5

Left Tank Water Leak Test is Good!

Quick note. I filled the left tank up with water yesterday to do a pre-baffle install leak test, and let it sit overnight.  I came down at lunch today, since I am working from home due to COVID-19 and checked on it.  There wasn’t a drop of water anywhere! So its safe to say this tank is good for its final sealing and closing.

I drained the water from the tank with a siphon hose, and moved the tank outside to sit in the sunshine to dry off completely.  I’ll leave it out there until I’m done working today, and then start the baffle sealing tonight!

Google Photos Link: https://photos.app.goo.gl/GgJydaoF2ajCsF8t8

Hours Worked: 0.25

Sealing the Left Tank Access Cover

Another quick build session.  I first wanted to do a initial water leak test, but that proved to be a bad idea.  Well, using the cork gasket as a temporary seal instead of sealant on the access plate proved to be a bad idea.  I filled the tank up with water, and things were looking good……right to the point of the access cover.  The cork gasket leaked pretty dang bad.

So I scrapped the water test idea for now, and I’ll permanently seal the access plate with sealant, and THEN test with water.  I was hoping the gasket would hold so that I could do this test, then remove the access cover for the final baffle seal so I could check the inner bay before sealing it up for good.  Oh well.  So, I brought the tank back in, dried it up, and then mixed up 20 grams of sealant for this access plate.  Then I scuffed up the access plate, and the rib and then cleaned it with MEK.

Then I slathered on a decent covering of sealant around the edge of the access hole making sure I got it nice and covered for the cover plate.  After that, I gently slide the access plate into place, and threaded in the stainless steel hex cap screws.  Before I let the screws bottom out, I smeared on some sealant using a toothpick on the bottom of the screw head / shoulders that way it would get a decent seal around the plate and prevent any seepage while keeping the screw accessible for easy removal in the future.  Here’s how it turned out.  In some of these photos you can see the screws are not fully seated, thats where I dobbed on the sealant.

Once that was done, I used the remainder of the sealant I had to do some touch ups elsewhere on the tank.  I had probably 8 grams or so of excess, and I didn’t really use all of it doing the touch ups.  I’ll let this cure and then do my water leak test. One step closer at least. Heres the time lapse:

Google Photos Link: https://photos.app.goo.gl/kKCQfhRiRXU8nHSq5

Hours worked: 0.75