Another short evening in the shop due to other stuff going on, but doing something is better than nothing.  I started with bolting the tiedown brackets onto the main spars.  Nothing complicated here, just plain old nuts and bolts.

Tiedown bracket in place:

Torque seal on the nuts.  These will be visible through one of the inspection panels under the wing, so I can make sure nothing is working loose:

Then I went to work riveting the right rear spar.  I had previously taped over rivet holes that needed to wait for other parts; luckily, I double-checked the plans before starting to rivet, because there were some holes I forgot to cover on the small reinforcement plates.  In fact, there were relatively few rivets on those plates that could be set right now.  The reinforcement fork, on the other hand…most of those go in place now.

Reinforcement fork: (the end closest to the camera will eventually bolt into the fuselage)

Inboard aileron hinge reinforcement plate.  Note that most of the holes remain unriveted:

That completed riveting on the right spar.  I guess tomorrow I’ll knock out lefty, and then it’s going to be rib prepping time…

Josie and I had a dinner date for her sister’s birthday, so most of the evening was booked up.  Still, after we got home I decided to go play in the garage for at least a little while, just to keep my hands on the project.  I clecoed all of the rear spar components together so they’d be ready for riveting maybe tomorrow night.  Some of the rivet holes need to stay open for ribs and other such stuff, so I taped over those to keep from riveting them.  Then I got the assembled tiedown brackets and went ahead and tapped them for the tiedown rings.  I had kind of wanted to get them bolted onto the spars, but I decided it was too late and called it a night instead.

No pictures, not much to see really.

I made a point of bailing out of the office right after 5 today so I could get home and finish priming those pesky rear spar channels.  After a quick stop at the farmer’s market for some dinner materials, I was home…except then I spent more time than I expected prepping for dinner.  No worries though, I still made it outside with plenty of daylight left.

I wanted one more coat of 7220 on the side of the spar channels I’d started Sunday, so I went ahead and shot that, then moved inside to work on the tiedown brackets. They were all primed and ready to go, so I clecoed everything together prior to riveting.  Even though I’m careful about marking all the parts, I checked them for proper fit against the spar just to be really sure before I started squeezing rivets.

I only had one hangup here-on one of the nutplate rivets, I got a little sloppy with the squeezer and the flush head ended up sticking up a bit.  Hooray, a drill-out!  As i calmly went to work on it, I thought back with some amusement to the time when drilling out a rivet was sort of sweat-inducing.  Of course, that pretty much guaranteed that something would go wrong.  After popping the head off the offending rivet, I start hitting it with the punch.  About the time I was thinking “I should be careful not to bend this nutplate,” I bent the nutplate.  So now I needed to drill out the other rivet and replace the nutplate…and apparently the other rivet was the most securely-set rivet I’ve ever done.  I went to town on that thing with the hammer and punch, to no avail.  Finally I hit on an idea – I got the rivet gun out with the flush set, and used that to hit the punch.  That got the thing out finally.

With all the rivets set, I walked back over to the spars for one final test fit.  Strangely enough, now the brackets didn’t want to fit between the spar reinforcement bars.  Hm.  I think when I checked before, the presence of the clecos prevented me from getting the assembly fully seated, giving me the false sense that the fit was fine.  Oh well, no big deal…I put each assembly in the bench vise and used the vixen file to shave a bit off the edges of each spacer, checked again, and everything fit fine.  Then I got to shoot primer on them yet again.

The brackets, after filing:

And with even more primer:

Meanwhile, the spar channels were dry enough that I flipped them and sprayed the other side.  I think these are finally ready to roll…that’s keep me busy one night, riveting the reinforcements into those channels.

Finally, primed spar channels:

In other news, I called Van’s on Monday about my backordered parts.  They’d just gotten in the tank rib, and had one batch of nutplates ready to go.  The tank attach nutplates, on the other hand, they still didn’t have.  Seems they’re having some issues with their supplier, and the expected ship date for those is around the beginning of May.  But they went ahead and shipped the parts they had on hand.  I guess I’m going to have to stop procrastinating and start taking care of ribs, since I’ve got some more time on those nutplates.

Yup, basically all I did today was deal with primer.  The afternoon was pretty busy for us since it was the first race of the MotoGP season; I’m a pretty strong fanatic and I’ve got Josie thoroughly hooked as well.  So some time had to go to that.  In between, though, I was able to take care of most – but not all- my priming issues.

First off, I decided to work on some of the rear spare reinforcement pieces.  While not as widespread as the spar channels, I had a touch of primer flaking on the reinforcement pieces as well.  I wanted to use those pieces as a test for my “fix” before going to town on the spar channels.  I started by sanding down the flaking areas, getting rid of the flaked areas and feathering out enough that I was removing what looked like well-adhered primer.  Then I cleaned the areas well with a tack cloth before shooting another coat of SEM.  This ended up working pretty well, though I didn’t know that until the end of the day.

Meanwhile, I moved on the priming the tiedown bracket pieces.  I’d already cleaned these pieces earlier and set them out in the sunshine to dry.  Since the pollen was starting to appear, I hit these pieces with the tack cloth as well before priming.  I also used NAPA 7220 on these; I decided from comparing in the past that 7220 was what I wanted to use in the future. (I only used the SEM on the spars because I had it and didn’t want it to go to waste)  There was no problem with the 7220 on these pieces at all.

Finally, it was on to fixing the rear spar channels.  I figured I didn’t have enough SEM to recoat these, so I decided to just sand them down thoroughly and reprime with 7220.  Unfortunately, I only had one can of 7220 on hand, and it went empty before I even got one side of the channels fully primed.  And since NAPA keeps bankers hours, there was no way to get any more, so that was pretty much the end of the day.  I’ll plan on picking up some more primer tomorrow and hopefully finishing up the spar channels tomorrow night.  Then I can finally get to riveting some stuff together!

I also want to maybe call Van’s tomorrow and see if I can get an ETA on my backordered parts.  Straightening and fluting the ribs is a pretty big job I could be getting started on, but I kind of would like to have all the ribs on hand before I get going on that; I like to do things in batches.  Though I guess I could just start working on the main ribs and then the leading edges, and leave the tank ribs for last, since that’s what I’m missing…but in any case, it’s been almost four weeks now since I got my wing kit, with no more information on the backordered parts.

I kind of wish I’d kept going on these tiedowns last night, because there was very, very little left to do on them.  Tonight I just clamped the nutplates in placed, drilled the rivet holes for the nutplates, and countersunk the backside of the spacers for the nutplate rivets.  Pretty simple, and not very time-consuming.  After just over half an hour, the tiedown brackets and spacers were ready to be cleaned and primed.

I guess I’ll be doing a lot of priming this weekend; I’ve got these pieces, and I still have to sand down and reshoot the rear spars that I had primer flaking off of a couple weeks ago.

Started the night by getting the drill press and band saw properly bolted down to the table.  It looks like a real workbench now!  Once the admiring part was over, it was time to get to work on the tiedown spacers.  The pieces were already cut to size, they just needed a lightening hole added before they got drilled in assembly with the tiedown brackets and spars.  The plans call for a 1″ diameter lightening hole, but the problem is I don’t really have anything that will make a hole that size.  A fly cutter would be handy for this, but…yep, don’t have one.  I decided instead to just make the hole 3/4″, since that’s the biggest hole my Unibit will make.  I figure the extra weight caused by making the hole smaller is pretty negligible.

The drill press worked like a charm for this stuff.  First, I marked diagonal lines between the corner of each piece to find the center.  Then I put a 1/4″ pilot hole in each piece, and followed with the Unibit.  The spacer material is a bit thicker than the depth of a step on the Unibit, so I had to actually drill from both sides to get the hole even.  Once that was done, I used a sanding drum on the Dremel followed by emery cloth to smooth out the interior of the holes.  A pass with the deburring tool on the edge of the tool and they were ready for drilling!

I made a lot of aluminum chips during this process:

The completed spacers:

The tiedown brackets are match drilled to prepunched holes in the spar itself.  The plans give dimensions for making a single locating hole in each bracket; these I drilled using the drill press.  Next, a bolt is dropped through that hole and the spar to locate the bracket, and a square is used to position the bracket in place and clamp it down.  The spacers I made before go between the brackets and the spar; I used some blue masking tape to hold them to the spar while I was lining up and clamping each bracket.  Then the spar gets flipped over and it’s drilling time!

That done, I laid out the parts on the bench (labeled so I know where everything goes) and looked back at the directions.  Next step is to drill the spacers to the brackets for the nutplates that will be used to attach the aileron bellcrank.  The spacers will be riveted to the brackets and nutplates, that assembly will bolt to the spar, and the the bellcrank will blot to that assembly. (whew!)  I kind of wanted to keep rolling, but it was past 10:00 and the air drill and compressor aren’t exactly the quietest things on the planet.

I settled for clamping one bracket/spacer assembly together before calling it a night:

Well, I tried to get some good work done on the tiedowns today, but it didn’t really work out.  First, I had to fabricate four spacers; the tiedown hardpoints themselves sit against the spar reinforcement bars and attach there with bolts.  However, the aileron bellcranks mount at the same location on the other side of the spar, and bolt into nutplates that will be riveted onto the hardpoints.  Since these mount points are inside the spar bars, the spacers go in there.  They’re pretty simple, just 2″ lengths cut from bar stock, with a 1″ lightening hole cut in the center.  They get drilled in assembly with the spar and hardpoint.

I made the first cut using the bandsaw…but apparently I need to replace the blade on that, because it really doesn’t want to cut straight, and wanders pretty badly.  I tried playing with the blade tension to no avail.  As such, my first cut produced a piece that was worthless.  So I made the rest of the cuts using the good old hacksaw, and then cleaned the cut edges up on the grinder.

At this point I had an odd sort of internal debate; the plans call for 3/16″ holes for the AN3 bolts, so I grabbed a 3/16″ bit from the drawer.  I went to check it against the predrilled holes in the spar and was kind of surprised when it didn’t fit.  Hmm, are the holes drilled undersize?  I wanted to be sure, so I got an AN3 bolt…huh, it drops right into the hole.  Even more odd.  Then I got the 3/16″ bit from my El Cheapo bit set…it drops into the spar holes OK.

I decided to drill a hole in my scrap piece using the apparently slightly oversize bit to see how the bolt fit in the hole.  The results sent me in a very different direction; while the bolt fit OK without a ton of apparent slop, the hole I drilled was kind of ugly.  Seems like it’s tough to keep the drill straight while going through thick pieces like this.  So I decided it was time for a drill press before I went to drilling these pieces.  After a little research, I settled on a model sold at Lowes.  

When I got there, though, the parking lot was oddly empty, despite it being about 6:30 and the door stating that they were open until 8 on Sunday.  An employee in the parking lot explained it to me…they closed at 6 due to it being Easter.  Ohhhh…well, so much for getting my drill press today.  Guess I’ll stop by again after work tomorrow.

So I just went ahead and knocked off for the day.  More to come tomorrow…

Yep, that’s all I did tonight.  I didn’t really expect to get a lot done, since I needed to pack stuff for the weekend trip to Chattanooga anyway, but I still wanted to get out and at least touch the project.  I’m still waiting on the backordered stuff, so starting on the tank attach nutplates is a no-go.  Didn’t really want to get involved with sanding down the rear spar channels and re-priming them either.  So I went to the next item on the main spars, where the instructions had me attach two nutplates to the inboard end of each spar.

I’d like to be able to tell you the purpose of these nutplates, but I have no idea.  There are references to drawing 11A of the center section, but that drawing is not with the wing kit, nor does it appear in my preview plans.  So I just gave up knowing what I was doing and just countersunk for the flush rivets and attached as directed.

I looked at moving on to the tiedown attach points, but looking over those instructions and drawings more carefully shows that there’s some fabrication of spacers and such to be done.  Since I didn’t want to get bogged down with that tonight, I went ahead and called it a (very short) night.

I’m planning to be back home Saturday night, hopefully I can get some god work done on those tiedown points on Sunday.

I had really wanted to get the rear spar stuff primed today…so I was pretty disappointed when the forecast weekend rain turned out to be a miniature monsoon this morning.  I was kind of bummed, even though there’s plenty of other work to do.  But then the rain cleared up and it looked like I’d have the whole afternoon rain-free!  So when I went out to the garage, I stuck with Plan A and went to work on the rear spar components.

Everything was basically ready to go, except that I needed to dimple the flange portion of the spar reinforcements and countersink the outboard row of web holes.  Since those holes will be covered by the outboard aileron hinge bracket, they need to be flush.  The countersinking was mostly uneventful, except that one of the holes is pretty close to the flange, close enough that the countersink cage interferes.  So I fired up the bench grinder and “customized” the cage.  No problem.

Now it goes in tight spaces!

With the countersinking done, I proceeded to dimple the flanges of the reinforcements.  Things were a little tight to dimple with the hand squeezer, but I got it done, without problems…or so I thought.  On closer inspection, it turned out that I’d bent the flanges a bit on the reinforcements, such that they didn’t want to sit flush with the spar channel any more.  So I had to get out the hand seamers and bend the flanges back into place.  I really should go ahead and get an Avery vise-grip dimpler for tight jobs like this.

With that, I set about scuffing all the parts for priming.  I did the spar channels first, and wow…I was not prepared for the amount of work that took.  Up until now I’ve been mostly scuffing pretty small parts.  I went through two Scotchbrite pads just on the channels!  Once everything was scuffed and then cleaned thoroughly, I set them out to dry and took a break inside for a few.

Meanwhile, I needed some work to do in between shooting coats of primer.  If I move forward past doing the rear spar subassemblies, the next thing is to start cleaning up and straightening the ribs.  Or I could start looking at some of the main spar work.  Since I’d already been countersinking, I decided to stick with that and work on the main spar.  I’m still waiting on the backordered nutplates for the tank attach screws, but there was no reason I couldn’t get going on the inspection cover nutplates.

This was another good example of the new minimal instructions.  They just say something like “Countersink the main spar for the nutplates.”  They don’t mention that in addition to countersinking for the covers, the nutplate attach rivets have to be flush too.  So there’s countersinking before you can even get tot he countersinking!

There seem to be some different ways that builders have done this task.  The specific problem is that the countersink cutter needs a hole deeper than the thickness of the spar flange to keep it centered.  Some guys will use drilled pieces of wood for this, but the instructions simply note that a #40 countersink will center sufficiently in the #6 nutplate.  I just went with the Van’s method; I final-drilled the rivet and screw holes, countersunk for the rivet holes, and riveted the nutplates in place.  Then I came back and countersunk for the actual cover plate screws.

Countersinking the rivet holes (I used a block of wood to help guide the countersink cutter):

Nutplates!

And the finished product, nutplates in place and cover countersinks done:

It was somewhere in the middle of this that I made an unpleasant discovery.  See, I primed the spar channels first, then set them aside and worked on the other pieces.  When I finished work on the first main spar, and went to put it by the primed spar channel, I found this:

Not sure what went wrong here.  I scrubbed the spars thoroughly, and was 99% sure they were good and dry before spraying, but maybe I was wrong about that last one.  So I guess I’ll be sanding these down and starting over again.  It’s not really difficult work, but it kind of annoys me since priming was the #1 thing I wanted to get done today.  Tomorrow looks very rainy, and I’ll be out of town next weekend.  But hey, there’s plenty of other stuff to work on…