Right wing main ribs riveted to main spar

Finally time to make some finished parts!

 

Right wing ribs clecoed on

 My buddy Brian stopped in to buck rivets - made the process much easier

 We started off slow, and managed to put some rather large smileys in two of the rivet heads. I'll drill these out, but the good news is the rest of the rivets went in without a hitch. 2 out of 63 ain't bad.

 Down the rabbit hole...

 Ribs permanently attached!

Attaching the rear spar will be a bit more interesting. We flexed the ribs out of the way quite a bit in order to shoot squarely, after I realized that I never ordered an offset rivet set. I'll be ordering one of those, and I suspect it will get a lot of use wrapping up the wings. It'll still be tight quarters, though.

 

Wings: 3 hrs



Right main spar deburred, right skeleton match-drilled

 I test-fit the tiedown brackets to make sure everything lined up.

This let me get to know my new torque wrench, although it started a bit rocky. The "click" was more subtle than on the wrench I had borrowed from a co-worker, resulting in me overtightening a couple of bolts and cross-threading one of the nutplates.

With no way to back out the bolt, I had to use a cutoff wheel in my Dremel to cut the bolt flush with the nutplate, and then cut the nutplate down as seen below.

Fortunately I didn't damage the spar or tiedown bracket, however I followed that masterpiece up by breaking two of my pin punches trying to remove the rivets. S$F!@#

I replaced the nutplates, came to terms with my wrench & got the right tideown bracket fully attached. Finally. The left is waiting on replacement bolts that I ordered, but is partially attached.

An a more upbeat note, I got all main & leading edge ribs match-drilled to both spars on the right wing!

 And the mandatory peekaboo shot...

Front

I got all the parts disassembled, the right main spar deburred, and the girls helped me remove the blue vinyl from the rear spar to ready it for deburring & priming.

Sometimes I feel like this blog is just a chronicle of my mistakes, but I have to admit it was satisfying to take the ribs off the spars for the last time.

 

Wings: 4.5 hrs



Tiedown brackets tapped, primed

I bought a tap set on Amazon.com that turned out to be cheaper than any of the local options (including Lowes selling the exact same set). Never used one of these before, so I was a bit nervous, but it turned out to be fairly straightforward.

I clamped each tiedown bracket in my bench vise after match-drilling the rivet holes for the nutplates. Then it was just a matter of applying plenty of drilling lube and taking it slow & steady, fully backing out the tap several times to clean off the chips. I'm sure it helped that Van's had pre-reamed the brackets to the right dimensions.

And voila! Threaded receiver where one didn't exist. Too cool.

Right started

And complete!

I finish deburred, scuffed & washed the tiedowns and spacers.

Primed the mating surfaces, and will do the rest once the assembly is complete.

I started countersinking the wing rear spar doubler plates while the primer was drying, and for some reason the hand drill blew through the 5th hole I was working on. The frustrating part is I don't know why it happened; the only thing I can think of is that the hammer drill engaged, but why that would override the countersink cage stop I don't know. Grr. Replacement ordered.

 That was a good place to stop for the night. Riveting tomorrow! (Comedy tonight?)

 

Wings: 3 hrs

Wing rib & rear spar deburring, trim tab assembly, wing main spar countersinking

Didn't get many pictures of this session, but there was a lot of repetitive work happening:

 

I disassembled, deburred & dimpled the trim tab, primed the mating surfaces and installed the first 2 rivets on the trim control brackets.

 

I found while deburring that I had elongated one of the trim tab skin-spar holes, and had to drill it to #30. I know paint will *mostly* hide the fact that there's a larger rivet there, but I kind of like knowing where the warts are. Here's hoping there aren't too many.

 Meanwhile Erin deburred wing ribs (mostly lightening holes), Brian Judge deburred the wing rear spars, and I finished countersinking all of the #8 screw holes in the top of the right wing main spar.

 

Empennage: 3 hrs

 

Wings: 4 hrs



Left elevator tab bending, wing tank skin platenut drilling & deburring

I decided to tackle bending the tabs on the left elevator skin and trim tab. Rumor has it this is and the trim tab are the most common areas for mistakes on the empennage.

I stripped the vinyl from the tab area and marked a line perpendicular to the trim tab cutout. Then I fabricated some bending blocks at an 11 degree angle based on a survey of other builders' sites and a check with my protractor of the elevator finished angle.

The blocks were taped into place with double-sided tape. The pictures in the manual describe clamping it to the table, but they only show this for the trim tab, and I couldn't find an effective way to clamp the blocks while leaving myself enough room to work. Instead I clamped the elevator and the rear spar on both ends and hand-clamped the blocks while I worked first the bottom tab, then the top.

My lines must have been slightly too far inboard of the ideal, because I had to file the edge of the bottom tab to get it to clear the upper tab (in the photos, the bottom side is up).

Other than the filing, with some patience, a block of wood, and finishing the tab with the rivet gun & mushroom head set at 10 psi, the bottom tab moved into place.

 

The upper tab seemed to go smoothly as well until I hit it with the rivet gun. The block must have moved out of place, causing the radius of the bed to go from 1/8" (per spec) to about 1/64" (too small).

This could be a problem as radii less than 1/8" can lead to cracking at the bend.



I'll send the photo in to Vans and see if I need to remove the tab and fabricate a replacement, or if it's acceptable and just bears close inspection to ensure cracks don't form.



Aside from that minor setback, the tab bending was easier than I expected. I set the elevator aside and with help from Brian Judge pulled out the wing spars to mark orientation.

We noticed a spot near the etched serial numbers that looked like corrosion; it appears that the riveter may have skipped off the surface. I removed the corrosion with scotchbrite, and will clean & prime this later.

We drilled out the #40 holes for the tank skin platenuts, Brian deburred on the inside of the spars while I worked with the countersink on the outsides.

And then with the help of this lovely assistant we squeezed the first rivets on the wings!

Brian got to try his hand using the squeezer - his first rivets on the plane.

While I continued chewing aluminum with the countersink, Brian started edge-deburring the right rear spar.

We made great progress, and are officially started on the wings!! And almost exactly one year to the day that we started the empennage it's essentially finished - right on schedule. Not bad for a spring and summer where it felt like we were never home.

 

Thanks again to all the family & friends who've helped so far, and for those who haven't - you will.

 

Empennage: 2 hrs

 

Wings: 3 hrs

Elevator counterweights drilled, Rudder trailing edge prosealed

 

 

So today I tackled two different tasks I've been avoiding. First up: prosealing the trailing edge of the rudder to prep it for back-riveting. I touched up a few countersunk holes on the AEX wedge to help the dimpled skins better seat in them, and then re-verified the alignment of the trailing edge to within 0.10" - it was. With help I re-scuffed the trailing edge parts with Scotchbrite & cleaned them thoroughly with naptha.

 Proseal is a watertight elastic sealer that is primarily used for sealing the fuel tanks. It's working consistency is somewhere between tar, old bubblegum stuck to your shoe, and chocolate pudding.

In this case, because it's very sticky, we're using it to bond the trailing edges of the rudder skins to the slim aluminum AEX wedge that allows for a very narrow and yet sturdy trailing edge.

 I mixed up a small batch and spread a thin layer first on the right (down) side of the wedge with a popsicle stick. I then flipped the wedge over and slid it into place, secured one end with a cleco to prevent slippage, and grabbed an unsuspecting assistant to hold the left (top) trailing edge open while I buttered the top of the wedge.

 We clecoed on the aluminum angle that I had previously match-drilled and wiped off some of the proseal that squeezed out with naptha and it came right off. The proseal needs to cure for a couple days, at which point we'll remove the clecos and angle & backrivet the trailing edge.

 Next challenge: match drill the elevator counterbalance weights. Which are lead.

I started by filing the surface down to fit the weight to the end rib assembly. Once I had good fit, I pilot drilled the holes #40 about 1/8" deep and removed the weight to drill through on the drill press.

The drill press kept trying to kick to the side, so I stopped - I'll need to figure out a way to take the lateral slop out of the press a different day. Today, it meant I was drilling manually.

I reassembled the right counterweight with the counterbalance skin & ribs and proceeded to break off 2 #40 drill bits. $&^%!

After taking a break to clear my head, I came back & was able to get both counterweights match-drilled to #12 by drilling only 1/8" at a time, removing chips & allowing the bit to cool completely, and using lots of lubricant on each of the bits (#40-#30-#21-#12).

After those two projects, it was a relief to get back to simple rib-spar match drilling, attaching the root ribs, & both elevator counterbalance assemblies.

 

Elevators: 5 hrs

Stupid strikes again

Today's session started off well; I clecoed the nutplates to E-615 in preparation for riveting.

 I had some help squeezing a couple of the rivets...

 And the finished product! I really enjoy using the rivet squeezer; it gives consistent, excellent quality results every time.

 As you see in the background of the above, Erin came out to help prep the elevator skins for backriveting. I jumped in and backriveted several lines, frustrated with my inability to get properly formed shop heads. I tried several different air pressures, different angles with the rivet gun, confirmed I was using the right length rivets, all with no improvement.

 And then it hit me: I had failed to put the stiffeners on and riveted the skin to...itself! $*!%&

 

I then made another mistake: proceeding with riveting on stiffeners, thinking I'd come back and drill out the stiffener-less rivets later.

Big mistake. I started carefully drilling out the malformed rivets, and somewhere around 1 in 3 or 1 in 4 were deforming the skin or damaging the dimple.

 

The first thing I did right was stop drilling, but now I'm stuck with the unpleasant alternatives of buying a new skin & stiffeners or attempting to drill out all the crap rivets and, with Van's concurrence, drilling the holes larger, deburring, dimpling, filling the enlarged holes with oversize rivets and adding additional rivets in-between for strength.

 

The latter solution appeals to the thrifty part of me, but drilling the holes larger will almost certainly result in edge-distance problems as at least 2 of the damaged holes thus far are larger than 1/8" rivets could fill. If the rivets aren't structural it may not matter and all of the damaged holes are on the bottom of the right elevator which means the error won't be visible. BUT - I'll know it's there.

 

I think I'm going to call Van's to consult their technicians tomorrow; however I think for $100, a little humble pie, and increased peace of mind the new skin is probably a small price to pay.

 

Lesson learned here is take it extra slow when I'm coaching other people, and talk through each step as I'm doing it.

 

Empennage: 2 hrs

Rudder assembly & elevator stiffener, skin prep

With everything for the rudder primed we started squeezing rivets, beginning with the nutplates and reinforcement plates.

 

This is my first installation of a nutplate; they're threaded receivers for screws or bolts of varying sizes that are riveted to the structure of the plane. The screws & bolts are how temporary or removable parts are fastened - think inspection hole covers, instruments, control surface bearing rods, etc.

 Audrey was a big help placing rivets and keeping the shop full of smiles.

 Nice work, Audrey!!

 Some balding guy snuck in to squeeze some rivets...

 But he did ok.

 The first couple attempts I made at riveting the nutplates resulted in some ugly shop heads on the rivets; after while I realized it was a serious bonehead error - I was using rivets 1 size too long!

I was able to remove the nutplates without damaging the spar or reinforcement plates, but after placing the nutplates into a bench vise to remove the crappy rivets with a combination of drilling #40, #30 & twisting with needle nose pliers, I found that I'd removed metal from both nutplates. 2 more errors for the "oops" jar, and 1 more lesson in humility.

I'm planning to rob Peter to pay Paul (seriously, when did that actually happen in the Bible?) and grab some nutplates from the wings to finish the elevators. Eventually I'll have to order more from Aircraft Spruce, but I figure I'll screw something else up before then.

 Above picture = manufactured heads on the thinner material (spar).

 I riveted the rudder horn & nutplate at the bottom with the squeezer for all but the upper, outside-most rivets. Those I had to bang/buck with the rivet gun.

 Next I riveted on the rudder counterbalance rib & skin, the former with the squeezer and the latter with the rivet gun & bucking bar. Even with breaks between build sessions, bucking rivets comes MUCH more easily than it used to!

So about the time I was gaining steam, it was time for another "oops." Did anyone catch it in the last post?

 

That's right, like a moron I primed the OUTSIDE of the counterbalance skin! Grr... At this point I'm going to proceed with riveting it on for practice, and if I find that paint won't cover it later, I'll drill out the rivets and install a new skin.

 With the rivets set, the next step was to fit and install the rudder counterweight. It needed several spots filed slightly to clear the rivet shop heads.

However, once it fit, I realized that the #8 dimple I created in the counterweight rib isn't sufficient. I've ordered a #10 die set to re-dimple the rib, but I'm disappointed that Avery Tools' "deluxe" die set didn't include an essential pair. Moving on...

Brian came over to help for a while, filing channels on the counterweight and marking and cutting (with my lovely wife) on the skin stiffeners for the elevators.

Sunday we match drilled and deburred most of the stiffeners. Tedious work, but fun to be on a new part!

 Erin wasn't too sure about drilling on the skins, but she was game for drilling the nutplate rivet holes to size, stripping blue plastic, marking pieces and (her favorite) hole deburring.

 

Meanwhile I was match-drilling the skins to the stiffeners & working the Scotchbrite wheel.

 We finished about half of the stiffeners & elevator trim plate (E-615).

 Good teamwork, and a productive weekend! New tools are on order - the #10 dimple dies as well as a thin-nose yoke for the rib tip rivets - and I'm debating ordering a longeron (flange) yoke for the rivets on the rudder horn brace. I don't have a bucking bar that will fit, so I either accept using a few pop rivets or bite the bullet and order new tools. We'll see what part of my nature wins.

Time-lapse:

 

 

Empennage: 9 hrs