Wings

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.

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.

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…

I’m a little disappointed in myself for not being very productive this weekend.  I did finally start getting my feet wet with prepping the wing ribs, but that seems like kind of a daunting task.

I started out today by riveting the remaining rear spar.  This kind of work I can roll on all day long…it’s straightforward and the results are obvious.  I did, however, manage to mangle my very first rivet, so I had to drill that little bugger out and replace it.  But I got the rest of the rivets shot, and that left me with the decision of where to go next.  I’ve really been putting off this whole rib prep thing, but as of that moment, there wasn’t anything else to do.

So I pulled out all the ribs and set them out on the workbench:

Step A was to deburr the edges.  For the long edges, I fired up the bench grinder and went to town for what seemed like an eternity.  Actually, it really wasn’t that bad, but it was definitely getting tedious already.  Next, I went after the lightening holes with a small scotchbrite wheel in my die grinder.  Side note: Extended use of the die grinder pretty much equals extended running of the air compressor.  It doesn’t take long with that thing to trip the pump, and apparently the pump can just barely outpace the die grinder’s air usage.

Okay…now what?  I still needed to work on the edges in all the little cutouts, like at the corners of the ribs and the tip of the nose ribs.  Problem is, most of those holes are too small for my files to get into effectively.  I think it’s time to invest in some needle files for getting into these tight spaces.  Okay…if not that…I guess I’ll start looking at straightening the flanges.

The intent of this operation is to ensure that all the rib flanges are at right angles to the rib face.  This will help ensure that the wing skins sit nice and flat.  This, along with fluting the ribs to remove any bowing induced by the forming process, seems to be regarded as one of the more dull and time-consuming tasks of the build, and I can see why.  I set one rib out, grabbed a small piece of aluminum angle to use as a square reference, checked the rib…hmm, this seems pretty good actually. I tweaked the flange a bit with the hand seamers to make it even better, but suddenly I felt like I wasn’t sure if I was doing this right.  The angle piece I was using didn’t really sit flush against the rib, and I was skeptical if its usefulness as a reference.  I just felt like I needed to do some reading on this subject before diving in.

I feel like this is probably some combination of generic do-it-right jitters with my procrastinatory nature.  Faced with a tedious task, I found an excuse to stop, go in, and do some research.  And then I found other things to occupy my time, such that I didn’t go back out in the garage again.

On the one hand, this is particularly annoying to me since my free time is limited in the near future.  I’m doing CPR classes after work three days this week, and the next two weekend are booked up with other activities.  On the other hand, maybe it’s better for me to attack this rib prep in small doses, instead of trying to bang out a ton of them over the course of a Saturday or some such.  At any rate, I’m just going to have to push through…at the end of the tunnel, I’ll have an assembly that looks like a wing skeleton.

Which reminds me, I’m going to have to build my wing racks at some point here too…

Well, the CPR class after work didn’t happen today.  The class was sponsored by my office, but we’re in the news business, and the stuff up in Boston caused some technical problems with us.  Since most of the people who’d signed up for the class were busy handling that mess, the class was pushed to tomorrow night.  I’ll be honest…I didn’t really want to go work on the ribs tonight.  I think it still seemed like a big tedious task, and it was easier to just procrastinate.

But I didn’t do that.  I went out and got to work anyway, starting with the right wing leading edge ribs.  The process is pretty straightforward: bend the flanges to a nice right angle with the rib face, and flute the ribs to take the bow out of them.  I decided to take extra photos tonight to help document this process.

This is a shiny, new, untouched rib.  Notice how the center of the rib isn’t even touching the table due to the bow caused by the forming process.  This isn’t going to work; the rib needs to be straight.

Some work with the fluting pliers pulls the rib back in line:

The flanges are also frequently not square:

But a little work the hand seamers brings them back into line:

Of course, it gets a little more complex than that in the curved portions of the leading edge ribs.  See, fluting the flanges also tends to bend them relative to the face, and bending them tends to change the fluting job.  In practice, I found that the best procedure for the leading edge ribs was to flute first, then go back and bend the flanges square, then go back and fine-tune the fluting before making one final check of the flanges.

Josie came out and got some photos of me slaving over the ribs.  Bending flanges:

And checking squareness:

So yeah, 90 minutes and I managed to prep exactly six ribs.  The good news is that the leading edge and tank ribs should be the tougher part of this job; their curved profile means lots more distortion.  The main ribs should be comparatively easy.

After that tedious work, I decided it was time for one of those temporary assembly tasks that serves no purpose except to give me hope.  In this case, I clecoed those newly prepped ribs to the leading edge skin.

That’s it for tonight; maybe I can get to work on the right tank ribs later this week…

Ugh.  I don’t do well with tedious work.  Which is unfortunate, because this rib prep stuff really fits the bill.  I guess that knowledge is part of the reason I haven’t been out in the garage much lately, although I have been out of town the last two weekends, so that’s a kind-of excuse.

Anyway, today I actually managed to get myself out in the garage after work.  The tank ribs for the right wing seemed like the next logical attack point.  Hoo boy, are these things all kinds of wonky.  Definitely worse than the leading edge ribs…I’m guessing that since (I think) they’re thicker material than the leading edge ribs, they’re more susceptible to warping.  I worked on one of the things and got it mostly straight, but man, I just did not want to keep doing this stuff.  I went back in the house for a bit.

When I came back out, I decided that maybe what I should do is try something a little less challenging.  So I put the tank ribs aside and went with the main ribs.  I figured that since they’re less curved than the tank ribs, they’d be easier, and I could boost my sense of achievement.  Well, I guess they really are simpler, but on the other hand they’re bigger.  It seems a lot easier to put a twist in these things if you’re not careful while fluting.

Oh well.  I got three of them done.  Yep, 90 minutes in the shop, and a grand total of four ribs straightened.  Seems like it’s going to be a real grind getting these things done.  I’m probably like 15% done with these ribs so far.

Had a nice turnaround from my last evening in the garage.  Maybe I was just in a more productive state of mind or something.  Maybe it had something to do with hanging out with the Falcon RV Squadron guys over the weekend, which afforded me the opportunity to try out the front seat of an RV-8…which in turn afforded me the opportunity to look out over the nose and imagine nothing but clear blue sky out there.

Anyway, I digress.  Last time I did on tank rib and three main wing ribs in about an hour and a half.  This time I finished the rest of the right wing ribs – eleven in all – in less time.  I celebrated this milestone by performing another one of those completely-unnecessary-yet-totally-giggle-inducing temporary assemblies.  I got out the appropriate inboard skins and clecoed together the inboard wing section. (minus the spars, of course)

Stack of finished ribs:

Wing section assembly:

In addition to my motivational problems last time out, I think that there’s some technique making a difference here.  Fluting has an effect on the squareness of the rib flanges and vice-versa.  It seems that fluting tends to make the flanges bend outward a bit, which then has to be corrected, which in turn undoes a bit of the fluting, and so forth and so on.  I think previously I was maybe fluting too much, which caused the flanges to need extra tweaking, which caused the flutes to need tweaking…this time, I tried to start off fluting less than I thought I needed and creeping up on a good level of straightness, and I found that the flanges seemed to need less work to straighten up.

(or maybe I’m less of a perfectionist this time out, I dunno)

Finally, a good productive weekend day in the garage.  Things started out kind of rocky…when I started working on that first tank rib, I found myself right back in I-really-don’t-want-to-do-this-tedious-work land.  But eventually I just put my head down and kept at it, and before long I was rolling through ribs at a pretty good clip.  It seems there’s a pretty strong mental thing going on here.  It kind of reminds me of when I actually used to run.  The first five minutes or so, all I could think about was how much I didn’t like running, how I wanted to stop, blah blah blah.  In those five minutes, decided to stop was an easy decision to make. (fortunately, on a lot of those runs there was an, um, very encouraging Marine Gunnery Sergeant on my tail)  But once I got past that point, it was pretty easy going.  I got past the discomfort and just cruised.

Anyway, I guess the ribs are kind of like that.  I just have to plow through the initial unpleasantness, and once that’s done it’s almost a cakewalk.

All told, I got through the tank ribs for both the right and left wings today.  That just leaves me with the left wing leading edge and main ribs.  I expect to get those knocked out tomorrow.  Josie also came out and worked on deburring the ribs I already straightened.  I hit all the easy rib edges a while back with the bench grinder and die grinder, but there are still lots of nooks and crannied on these things that need attention.  This is more tedious stuff, but Josie says she actually finds the deburring to be kind of relaxing.  I’m more than willing to let her take care of that stuff.

My minor reward for being productive today was clecoing the right tank ribs to the tank baffle, giving a little preview of what the inner tank structure will look like.

Luckily, I should only have to make up one more title like that.  I got through all the left leading edge ribs and four of the main ribs tonight.  That just leaves ten main ribs to straighten, and the mains actually go pretty quickly as compared to the leading edge/tank ribs.  It was a little brisk out on the garage, so I worked inside at the coffee table with Shawshank Redemption playing in the background.  I even recruited Josie to snap one of those “prove you really did build this thing” photos.

That’s it for the work summary, though I feel compelled to share a brief humorous tale regarding making assumptions.  I’m pretty sure I’ve mentioned here a few times the backordered parts from my wing kit, in particular the large number of tank attach nutplates, which represent a significant amount of work to be done on the main spars.  When I called Van’s back in April to check on my backordered parts, the impression I got was that they had my missing tank ribs and the nutplates for the stall warning kit, but not the tank attach nutplates; they went ahead and shipped what they had.

When that box arrived, I found the two tank ribs and a paper bundle.  I admired the ribs, and just stuck the bundle on a workbench somewhere.  Since I’m not planning on even using the stall warning kit (I want a real AoA system instead), I didn’t even give that bundle the time of day.  Since that time, I’ve lamented on several cccasions how I wished I could be taking care of those tank attach nutplates, blah blah blah…

Well, today I got a package from Van’s.  Finally, my prodigal nutplates!  I opened the package and found…ten nutplates.  I was expecting the 210 tank attach nutplates. I was quite confused.  A look at the inventory sheet revealed that these were, in fact, the stall warning nutplates.  Wait, then what’s in that bundle that’s been collecting dust for four weeks?

You probably guessed it.  It contained those 210 tank attach nutplates.  The stupid things have been gathering dust in the garage while I complained about not having them yet.

*sigh*

Yep, sat down right after getting home from work and took care of the last ten before heading out for dinner.  I’m glad to have that behind me, though there’s stil the drudgery of deburring these things…oh well, a little bit at a time.