Wow, talk about a roller coaster day.  When we left off last time, I’d dimpled E-606PP where I was supposed to countersink, and I stopped the work day right there while I decided how to handle that little mistake.  After some hearty discussion with the hive mind at VAF, it seemed that the best course of action was to flatten the dimples I’d created, countersink the piece like it was supposed to be, and move on.  Just to make sure, I performed a test on a piece of scrap of the same thickness as E-606PP; I drilled a #40 hole, dimples that holes, flattened that dimple, and then checked the flatness of the material and the hole size.  Hole size looked good, and while the material wasn’t perfectly flat, it was certainly acceptable.

Hooray, I don’t have to throw yet another piece in my scrap pile!  Or so I thought…I immediately got to work with the squeezer and flat sets, going down the line and flattening those pesky dimples.  Nothing to it…hmm, wait…now the spar piece looked like it had developed a bit of a bow, and was no longer straight.  I attempted to cleco it in place on the elevator skin…yup, it is definitely no longer straight.  Hmm…well, luckily, I do have tool specifically designed for straightening pieces like this; in fact, it gets used on pretty much every rib with a curve on the plane.  So I broke out the fluting pliers and went to work on the spar flange.  Five minutes later, and it was straight again.

Oh, wait a second…the whole reason I had to flatten those dimples was because the hinge attaching the trim tab needed to sit flush against the inside of the spar flange, which I had just proceeded to put little flutes in.  Well, maybe it’ll be OK once I get everything together…I went ahead and broke out the countersink.  After setting the depth properly (a trial-and-error affair I don’t particularly enjoy), I went to work on the spar.  The very first hole I countersunk…something didn’t quite feel right as I was doing it.  I pulled the countersink bit out, and somehow I’d managed to wallow the hole out to an oblong shape.  Clearly this spar just wasn’t meant to go on my aircraft.  Into the junk bin you go!

In retrospect, it was probably trash as soon as I decided to flute it.  I don’t think that assembly would have gone together right with those flutes in place.  It just so happened that I buggered up the countersinking, which in turn made me make the decision to replace.

This, in turn, changed my plans for the day significantly.  Originally, I’d wanted to fix E-606PP, go clean all my skeleton parts, and then shoot primer on them once they’d dried.  Then I’d have everything ready when it came time to rivet the elevator.  Well, there’s no point hurrying to prime everything when I’m going to have to wait for a replacement part.  Instead, I decided to attack the “ears” for the trim tab and the elevator trim tab cutout.  These things have a pretty solid reputation among RV builders as Things That Are Frequently Buggered Up.  I figured I’d go ahead and go after them, and if I messed something up, I could at least order all the replacement parts at once and save on shipping.

A little more on these bends: The trim tab, as well as the edge of the trim tab cutout in the left elevator, don’t have ribs like the ends of most other surfaces.  Instead, there’s extra material on each side of the skin; these little tabs are bent down and riveted together to close off the ends of these pieces.  Many builders, frustrated with the difficulty of getting these bends right, have taken to simply cutting the tabs off and fabricating custom “riblets” instead. (example)  Over the past couple of days, knowing that this task was ahead of me, I did quite a bit of reading on the subject, seeing how other builders had done the bends.  Opinions on the task ranged from “not really that bad” to “nigh impossible.” (I’m paraphrasing here; I don’t think I’ve actually run across a build log yet that used the word “nigh” in a sentence)  Anyways, I decided to go ahead and try the bends.

If one is following the instructions, one will end up bending the tabs on the elevator first.  Which I did, which was, in retrospect, a mistake.  There’s a lot more stuff in the way of the job in the elevator than the trim tab, plus there’s just a lot more material around that you have to work around while bending.  I know that now, but I didn’t know that when I started this task.  So first up, I endeavored to fabricate a bending block.  The instructions say to use wood or particle board; I happened to have some scrap MDF left over from my workbench build, so I decided that would work well.  A little work with the band saw and belt sander, and I had this little guy:

He seemed to be up for the task.  OK, next step, mark the bend line on the elevator.  Here again, access is kind of difficult; after a few attempts to wrangle a square and Sharpie in there to make the line, I adopted a plan B.  I went ahead and stuffed the inside portion of the bending block in place, then used the square to move it around until it was square to the cutout area and in the proper position.  Then I used the Sharpie to mark where the block would sit.  Now I needed to secure the block in place.  The instructions say to use double-sided tape, but I didn’t have any around.  No problem, surely the old trick of making a tiny roll of single-sided tape would work, right? (Spoiler alert: the answer is NO)  With my blue masking tape in place, I got the block in position, added the outside piece on top, and clamped the thing down.  Then I got another block of wood and started tapping on the tab.  Oh cool, it’s starting to bend…oh crap, the inside bending block is moving out of place.  ABORT!!!  Great, now I have a slight bend that’s too far in and not straight at all.  I tried resetting the whole jug and bending again, but the block moved again and I just made the nasty bend worse.  OK, it’s time to stop and rethink this thing. 

This was the first time in a while that I really let a mistake get to me.  I’ve been pretty good about taking things in stride, fixing them or replacing stuff as needed, and moving on if possible.  This time, though, I was facing replacement of the whole elevator skin, probably $100 in parts at a time when I’m already worried about getting the funds set aside to pay the balance of my wing kit.  Rationally, I knew I could probably save the elevator skin, but it was one of those time when emotion completely overrules rationality.

I went inside to do some more reading on the subject.  After about 30 minutes of actually reading, instead of just skimming for the stuff I wanted to hear, I learned that there were a few key points to getting these bends right:  Using hard material for the bending block, using good double-sided tape to ensure the block didn’t move, and making sure the assembly was clamped very, very tight.  I’d been using a couple of these clamps; they’re great for general use, but there’s a limit to how much clamping pressure they can exert.

So off I went to visit Lowe’s Aviation Supply; half an hour later, I was back home with a chunk of red oak, two 6″ C-clamps, and a $10 roll of carpet tape, which I was about to use maybe 2% of before putting the rest of the roll on a shelf for eternity.  Oh well, such is homebuilding.  

I set about making a new bending block set.  The first time, I’d tried to measure the angle of the elevator trailing edge and recreate that; this time, going off another idea I’d read, I used the elevator root rib to get the angle right and draw my cut line.  The result was much better-looking than my first attempt.  I also decided to bend the trim tab and then move on to the elevator if I could get the technique right.  A bunch of careful minutes later, I had the block in place inside the root end of the trim tab:

…and clamped down with the other half of the block setup:

Once again, I went to work with a hammer and a block of wood.  This time, things went great, actually beyond my wildest expectations.  After getting the bend mostly done, I finished it with the rivet gun and flush set, then repeated the process on the top side.  It came out looking absolutely beautiful:

Repeating the process on the other end of the tab was a piece of cake.  It went so well, in fact, that I decided to capitalize on my rejuvenated work day and try to save the elevator.  The one good thing was that the bend I fouled up was on the bottom of the elevator; if I could flatten it enough to be safe, but not necessarily perfect-looking, at least the only people that would notice would be small children…

So I got the elevator skin back out, cleaned the tape off the bending block, stuck it in the trailing edge, and used it as a backer while I worked over the bad bend with the rivet gun and the flush set.  I wasn’t able to straighten it out completely, but it was definitely OK to try bending again.  So I did the whole deal again.  It was a little tougher this time; the inboard trim tab cutout part of the skin gets in the way of bending the forward part of the tab.  I ended up doing the rivet gun portion in two stages; I’d hit the trailing edge area as much as possible, then move one C-clamp so I could get at the rest.  The result wasn’t as perfect as the trim tab, but still acceptable to me:

The only concern I have came when I got out that trim tab skin and held it in place on the elevator.  Right now, the outboard edge is barely making contact with elevator tabs that I bent.  At first I thought maybe I should have bent the elevator tabs further in, but I couldn’t do much more without them interfering with each other. However, upon closer inspection, the tabs on both the trim tab and elevator aren’t bent quite to ninety degrees; I think once both spots are riveted in place, it will pull the tabs in enough to eliminate the contact.  If not, I may have to order another trim tab and bend it a little differently to shorten the whole unit a touch.  Hopefully that won’t be necessary…I’ll probably seek the feedback of the VAF folks on this one too.

So all in all, quite a day.  I went from small failure to larger failure to great success, and ended up at “I think this is going to be OK.”  Roller coaster indeed.

EDIT:  OK, after further consideration and inspection, I’ve decided to cut out the bent areas in the elevator and fabricate a riblet to go in there.  I got to thinking about the clearance issues, looked at my preview planes for clearance specs between the trim tab and elevator, and got concerned about being able to meet the minimum clearance.  I decided to run out to the garage and clamp the ears together to sort of “preview” what the ears would look like once they were riveted.  When I did that, I suddenly noticed that the elevator bend isn’t even straight; towards the trailing edge, it curves outward, and that’s where my clearance problems would be.  Not good enough for my plane, so it’s coming out.

Decided to spend a little time out in the garage tonight; I’d like to be able to get these skeleton parts primed this weekend if possible, which means I need to get deburring, dimpling, and other prep done before then.  And about half of tomorrow is out because I have to attend a CAF meeting down in Peachtree City.

Anyway, things were pretty straightforward.  I got comfortable in my Official Deburring Chair and started going to town on the skeleton parts.  Once all the holes were taken care of, along with the nooks and crannies where the bench grinder can’t get to, I moved on to the aforementioned grinder to take care of the edges of everything.  Once I’d finished that, I was about an hour in.  Next up: Dimpling.  Again, no worries here; I went to town on the spar, ribs, and the short rear spar for the left elevator, E-606PP.  This piece closes off the trailing edge of the elevator where the trim tab mounts.

Of course, just as I was thinking how productive I was being, I found out I’d done something dumb.  I’d actually decided to stop for the night and go spend some time with Josie, but before I went in, I wanted to read ahead in the directions a bit.  Just a couple steps ahead, there was instruction to the effect of “Machine countersink the top flange of E-606PP and dimple the bottom flange.”  Hmmm, I just got done dimpling both flanges.  Why would it need to be countersunk anyway?

Oh, wait.  The hinge piece for the trim tab sits on that top flange.  Hence the countersink instead of dimpling, to give the hinge a flat surface to rest against.  ARGH!

At first, I tarted to go ahead and try to fix my mistake.  I figured I could use the rivet gun with flush set and the back rivet plate to flatten those dimples back out.  But then I got to thinking some more…first, if the dimples didn’t get flattened thoroughly, how would the countersinks turn out?  For that matter, how might that combination of flattening and countersinking possible affect those holes?  Hmm, alternative idea: Maybe I could leave the dimples there, an countersink the hinge itself so the dimples would sit inside.  Drilling the hinge piece in place might be a little more challenging, but I wouldn’t risk ruining E-606PP.

Bottom line, though, I got to this point by getting ahead of myself and working without thinking.  Trying to figure out in a flash how to fix my mistake was liable to end up with me compounding that mistake, so I decided to leave things as they were, quit for the night, and seek the advice of the hive mind at VAF.  So we’ll see if there’s an issue with my idea of countersinking the hinge that I didn’t think of.

Oh, I also did another time lapse tonight.  I figured it might be amusing to have footage of me going through the drudgery of deburring.  I even added some amusingly boring music this time.

When we left off last time, I was trying to decide whether to roll the leading edge of the right elevator now, or go ahead and start on the left elevator and roll both leading edges at the same time, once I finish the left and the time comes to hang both elevators from the horizontal stab.  I ended up making the decision based on a pretty boring rationale.  Specifically, I wanted to work in the garage tonight, but Josie had to work late, since it’s her busy season at work.  With no one to help roll the leading edge, and me itching to work, I went ahead and hung the right elevator from the rafters in the garage (it’s getting crowded up there!) and got going on the left.

All of the work tonight went pretty fast, probably because I’ve already done all this (with slight modification) on the right elevator.  I drilled the hinge reinforcements to the spar, drilled the two tip ribs together, then clecoed the counterweight and its skin in place on the tip ribs before drilling the two mounting holes for the counter weight.  Then I removed the counterweight, clecoed the tip rib assembly to the spar, and match drilled those pieces.  Next the root rib went on and was match drilled, and then it was time to cleco the skin in place.  With the skin in place, the clecos between the root rib and spar can be removed to make room for the control horn, which was the next item to match drill.

At this point we hit the slight difference between the left and right elevator, due to the presence of the trim tab.  The root rib is of course truncated, and there’s a second spar that goes in the trailing edge of the elevator where the trim tab will mount.  The next step for me was to cleco this spar in place and match drill it to the root rib.  After that, it was just a matter of going all around the skin perimeter and match drilling all the holes between the skin and skeleton.

It was creeping up on 11 PM by this time, so after pulling the elevator apart again, I decided to stop there instead of getting started with deburring all those parts.  I did go ahead and countersink the counterweight for the mounting screws, even though that’s a few steps ahead.  This was mostly because I’d gotten my countersink out earlier to swap out bits, and I already had it mounted in my cordless drill.  I countersunk the right elevator counterweight using an air drill, and while the results were acceptable, there was clearly some wobbling of the countersink.  I decided that maybe it would work better to use a slower speed drill, which the cordless is good for.  It was a good strategy; the countersinks in this counterweight are flawless..

Also, what with the kind of benign nature of tonight’s work, I decided to forgo the usual few photos for something a little different.  When I was about halfway through clecoing the skin to the skeleton, I decided that a time lapse of the evening’s work would be a nice addition to the build log. (it also helps satisfy the “proof you built the thing” requirement when this project is done)  On the one hand, I wish I’d started the time lapse earlier; it would have been cool to see the elevator come together from individual pieces and then come apart again.  On the other hand, I neglected to change the camera settings before I started shooting, and thus I filled my memory card up in the space of about 50 minutes; given that oversight, I wouldn’t have been able to shoot the whole procedure anyway.  I also shot in 4:3 aspect instead of 16:9.  Oh well.

This thing’s almost done!  Kind of oddly bittersweet though…at the same time I’m pleased with the progress I’m making, and all the good feelings of seeing a part come together, I’m acutely aware that I’m getting closer to a period of no building while I wait for the wings.  Oh well…worst case, I can always work on the fiberglass stuff while I want, I suppose.

First things first, I still needed to deburr and dimple the elevator skin.  Nothing fancy here, just time-consuming.  I find the edges of skins to be some of the more tedious work; I’m just using an edge deburring tool on those, maybe a file for some of the tight spaces.  I’m thinking I should get a die grinder with a small scotchbrite wheel for some of these edge finishing tasks that don’t really work for the bench grinder.  I also went ahead and drilled the leading edge holes to #30; even though the instructions call for doing this after rolling the edges, I don’t like the idea of trying to hold that stuff in alignment, or the inability to effectively deburr the holes, or the drill shavings maybe getting inside the elevator.

Also, while doing the deburring and dimpling, I took a look at the pieces I primed yesterday and found a couple spots I wanted to touch up.  So in between working on the skins, I shot some primer in the driveway.  In order to speed drying, I resorted to hanging the pieces in front of my radiant heater once the primer had flashed dry.  This seemed to work well; when I worked with the pieces later, I noticed no problems with primer coming off in the areas I’d touched up, so I guess it hardened sufficiently.

Next up, riveting the E-704 and -704 tip ribs together.  These just sit together back-to-back and go together with some 470 rivets.  I decided to use the rivet gun on these, but for some reason the rivet set was really banging on the rib itself; I had a little ring of missing primer around each of the manufactured heads.  I found this odd, but for some reason my brain didn’t make the connection that maybe I was doing something wrong.  So I just took the new assembly out in the driveway and shot some more primer to fix those rings.

I moved on to riveting the reinforcements and nutplates to the spar.  I shot the first rivet, got the same ring around the manufactured head…and suddenly, I had an idea what the problem was.  Yep, I grabbed the wrong rivet set, I was using the set for -5 470 rivets.  That’ll do it…derp.  Swapped it for the right set, and magically all my subsequent rivets looked great!  Of course, I had one more spot to touch up with primer…and the next step was to start riveting ribs to the spar, which had wet primer.  So once again, I set my parts in front of the heater, and went inside to warm myself up a bit and have some food.

An hour later, things started really coming together.  I riveted the tip rib assembly to the spar, then flush-riveted the root rib to the spar.  It felt kind of odd to use 426-3 rivets on understructure, even though I understand the purpose…the control horn goes on top of this area.  Those control horns were the next item; 12 rivets squeezed and they were done.  Next the instructions say to rivet the E-713 counterbalance skin to the elevator skin.  That sounded a little odd to me, but a look at the plans made it all clear.  Most of the rivet holes where the elevator skin overlaps the counterweight skin also go through the tip rib or spar, and can thus be squeezed with everything together, but two rivets on each side only go through the two skins.  These two rivets would be inaccessible once everything was together, so riveting them first allows the use of solid rivets instead of blind rivets. (though I did notice that the plans specify optional blind rivets for those holes)

One thing the instructions didn’t specify prior to putting the skeleton in place was putting the dabs of RTV in the trailing edge where the stiffeners overlap.  I didn’t forget the need for this though; I put my dabs in before getting started with the counterweight skin. (which would have made it a lot harder to get back to the trailing edge)  I also gave the insides of the elevator skin a good wipe down with acetone before buttoning up.

Now the skeleton went into place, and it was a simple matter of just squeezing a bunch of rivets around the perimeter.  The main (minor) issues I had here were getting  the assembly on the workbench in a stable position so I could squeeze.  Since the counterweight was already in place, the thing really wanted to try and flop off the table.  Some creative use of wood blocks and boxes of clecos (to weight down the trailing edge) got me through this.  As with the rudder, I didn’t have any good way to use solid rivets in the tight spots at the trailing edge, so for the last rivet on both the root and tip ribs, I drilled out to 7/64 and used MK-419BS blind rivets.

This seemed like a good time to stop for the day; I’ll get Josie out maybe one night this week so we can get the leading edge rolled.  Or I could just wait and roll the leading edges of both elevators at the same time; this is the way the instructions seem to indicate.  I’ll have to have both elevators out once I’m done anyway so I can fit them to the horizontal stab; I suppose I could just do the leading edge rolling and other fitting tasks on a weekend day.  I’m not quite sure what I want to do, actually.  Maybe I’ll wake up tomorrow morning and come to a conclusion.

This is the tip rib assembly that I fouled up using the wrong rivet set, just after I shot some more primer to fix the lovely rings I made.

Here’s a blurry photo of the skeleton. (the photographer in me is annoyed with this picture.  Oh well.) (Also, that back corner is horribly cluttered. Definitely going to be another garage cleanup day in my future, before the wings arrive.)

And the (almost) finished elevator!

Started off the day with some flight time.  I’d originally reserved the plane intending to run over to the Spitfire Restaurant for lunch with Josie.  Then I got an email which reminded me that this was the first Saturday, which meant it was EAA 690 pancake breakfast day!  Even better, the breakfast program sounded interesting; a talk from the LZU tower manager.  Luckily, no one had reserved the plane for the morning, so I just edited the reservation to start earlier.  So we flew from PDK to LZU, ate pancakes, heard lots of interesting stuff about ATC, then flew over to WDR for lunch before heading back home.

After a brief rest back home, I strolled out to the garage to start priming.  This didn’t exactly get off to a great start…when I picked up the ribs, I immediately could see a discolored spot where the part sticker had been on one of the tip ribs.  Checked with my finger…it’s sticky.  Still got sticker residue on there.  I found the same thing on the other tip rib.  Apparently I was slacking when I was cleaning these parts…so I went to work on them again with Simple Green and a green pad and got the rest of the residue off.  But now I had to get them dry, and I didn’t want to wait another day to prime.  So I got creative.  First I used the blow gun on the compressor to blast as much loose water off as possible.  Then, I went inside and…um…used Josie’s hair dryer to finish drying the ribs.  Yes, really.

So then it was back to priming.  I was sort of pleased that I’d gotten past this little hiccup and moved on with the day…until I started shooting primer on the spar.  Immediately it was obvious that there were some oil spots or something on it, because the primer simply would not stick.  I actually watch primer migrate off these spots just after spraying.  Again…apparently my cleaning technique is getting really sloppy.  So I repeated my past performance, scrubbing the spar again thoroughly before blasting it with the air gun and the hair dryer.

Then, yet another problem cropped up.  I could tell that the can of primer I was using was getting low…and oh look, it seems to be the last can.  So I got to make a quick run out for a primer restock.

While I’m talking about primers…I think I’m going to try something new on some scrap pieces while I’m waiting for the wings to come in.  I haven’t been all that pleased with the Duplicolor stuff, despite some endorsements on VAF.  At first I thought maybe it was my technique, but I feel like I’m doing OK now, but quality is still so-so.  NAPA 7220 is another commonly recommended primer, so I think I’ll pick up a can and shoot some on some of my scrap pieces.  If I like the results, I’ll probably switch to that once I get going on the wings.

Anyway, despite some setbacks, I still got the skeleton parts primed today.  I still need to deburr and dimple the rest of the skin, but that should go fast, so I think tomorrow I can get going riveting the elevator.  Then I get to have more fun in the wonderful world of leading edge rolling…

Sorry, no pictures today.

Ugh.  I kind of feel like I squandered a lot of good work opportunity yesterday. (I did this work on Monday, and I’m just getting around to writing this up now)  First off, I slept in later than I probably should have, though on the other hand it is vacation…but anyway, my goals for the day were to get everything dimpled and cleaned for priming, and hopefully get around to priming while I had good weather and daylight.

Actually, it turned out I had a couple other steps to do.  In addition to the normal dimpling, I needed to dimple the rivet holes between the spar and root rib; these rivets are flush because the control horn must rest on top of them.  The instruction call for countersinking the spar, but I elected to dimple instead.  These same part will be dimpled where they join the skin, so I saw no reason not to dimple them here as well.  Well, until I got to dimpling the flange of the root rib…it was kind of tough to get those due to the acute angle between the flange and rib.  I had to break out the pop rivet dimple dies for this one.

Next, some of the edge of the counterweight skin needed to be tapered where they sat under the skin.  I decided to simply hit these up with the bench grinder to achieve the taper, but first I needed to mark the areas that needed to be tapered.  So I temporarily reassembled the tip rib components to the spar; with everything in place, it was easy to see where the edges of the skin would sit and to mark the counterweight skin overlap areas.  The taper itself was easy to do with the bench grinder and the scotchbrite wheel.

The rest of the dimpling went fast…well, 95% of it, that is.  The last few holes at the narrow end of both the root and tip ribs were pretty tough to do.  I probably spent twice as much time on those eight holes than I did dimpling all the other elevator components.  After doing some research, I think I’m going to invest in a set of Avery Tool’s vice-grip dimplers. (ARGH!  They’re out of stock!)  They should do a better job in the tight spaces than the sort of haphazard rigs I’ve been coming up with.

Then it was out to the driveway to scuff and scrub all the parts prior to priming.  Last time, I found out how much longer it took for this stuff to dry now that it’s cooled off outside…and it was even colder yesterday than last time.  I tried to jump-start the process by blowing the newly-cleaned parts with the air gun to get rid of some of the water, then I left them out to dry while I retired inside where it was warm for a late lunch.  After lunch, I was feeling a little tired, so I laid down for a nap…I wanted to give the parts more time to dry anyway.  I’ve tried to prime parts that weren’t completely dry before, and let’s just say that it doesn’t work well.

Unfortunately, when I woke up again, it was already starting to get dark.  Too late to get any priming in, and the forecast for New Years was rain, rain, and more rain.  This morning, I thought about trying to prime just inside the garage with the door open, but the primer specifically says not to use it when the humidity is high.  So I’ll just be waiting until this weekend to get back to work.

I think I’m going to go ahead and order my wing kit this week.  I’ve got the funds for the deposit, and getting the balance set aside during the eight week lead time won’t be a problem.  Most importantly, I’m going to be done with the empennage in the near future, and I’d like to minimize downtime.  I will need some time to clean and reorganize the garage for all the wing parts, but not eight weeks…

The tapered edges of the counterweight skin:

Look how much fun I’m having scrubbing the elevator parts!

Well, it’s been some time since I got in some weekday evening work, but I think I made up for some lost time tonight for sure.  A tick over four hours in the garage, and I’m down to just dimpling and priming before I start riveting the right elevator together!

The evening started with clecoing and match drilling the reinforcement plates to the spar.  Then I edge finished and fluted the E-703 and-704 ribs. (the instructions seem to call for doing this for the ribs to both elevators, so I did, then promptly tossed the left-side ribs back under the workbench)  The two ribs for the right rib got match-drilled, the I clecoed on the counterbalance skin, fitted the counterweight, and prepared to drill the counterweight attach holes.

I spent some time agonizing over this – here I had to drill a hole into the counterweight skin, through a couple inches of counterweight, and out through the end and counterweight rib flanges.  I was acutely aware that if I drilled at a bad angle, I could come out on the far side and be in a bad position on those flanges, and then they’d be ruined, I’d have to order more replacement parts, etc…

A drill press might have come in handy here, assuming I could have somehow mounted the rib/skin/weight assembly in such a way that I could drill it.  But since I don’t have a drill press, I set aside my fun air drills in favor of the cordless.  The sole reason for this is the cordless has a little bubble level on it, which I could use to ensure I drilled straight.  This technique worked like a charm…I was still all kinds of nervous, but the holes in the rib flanges ended up located quite nicely.

Next the counterweight came out and the end rib assembly got clecoed to the spar along with the root rib.  The root rib was match drilled to the spar, then out came the skin and the skeleton was clecoed into place.

The next step was to cleco the control horn into place.  I had a tough time getting that thing lined up…seemed like it wanted to really fit snug against the spar and rib, and I had to use a little grunt to get the holes to line up so I could cleco it in place.  This was made even more difficult due to the powder coating on the control horn – the holes are already undersized and tough to get the clecos through, and with the powder coat on top of all that, it’s even tougher.  But I finally got the thing clecoed in place and match drilled the rivet holes. 

Next I match drilled all the skin-skeleton holes, and took one last longing look at my temporarily-assembled elevator before tearing the whole thing apart again.  The counterweight skin was dimpled for the attach bolts, the counterweight itself was countersunk to fit against the skin, and then I got to spend some time in my Deburring Chair hitting up all the rivet holes and lightening holes before firing up the bench grinder one last time to finish the edges of the rest of the skeleton pieces.

I still have a couple unanswered questions I’m going to research before proceeding further.  The attach between the E-702 spar and E-709 root rib uses flush rivet, since the control horn has to sit on top of that particular joint.  The instructions call for countersinking the spar, but this material is thin enough to dimple…I mean, after all, I’m going to be dimpling the flanges where it mates with the skin.  I’m not sure why countersinking is specifically called for here, but I want to find out before proceeding.  I’d rather dimple personally, I find it easier to do consistently than countersinking.

The instructions also call for beveling the edges of E-713 where it tucks under the skin to provide a “smooth transition.”  This seems fairly straightforward, but I’m curious if there’s any particular technique here.  I feel slightly weird just going to town on the edges of the counterweight skin…

Anyway, I’m not sure if I’ll get in any more work until after Christmas.  Josie and I are planning to rent an Archer and fly to North Carolina to spend the holiday with my family, then head back home Christmas afternoon to catch dinner with here family, but the weather is looking iffy.  In any case, we’ll be gone all weekend and well into next week.  Hopefully I can get my dimpling done and prep and prime next weekend, maybe finish assembling the elevator during my New Year’s days off work.

Preparing to drill the counterweight

Completed counterweight attach holes.  You can see in this photo how much distance is between the skin and flange, and how there’s ample opportunity to drill crooked and cause a problem.

And the temporarily assembled elevator just before I tore the whole thing apart.

Jeez, another layoff.  I actually started on the back riveting last weekend.  I did get a bit done, but I needed a second set of hands and Josie was unavailable for reasons which I don’t remember.  So I just knocked off and intended to pick back up another evening in the week.  Unfortunately, I got extremely ill Sunday night and remained that way until Wednesday, at which time Josie came down with the same symptoms.  So it wasn’t until today that I was able to get back to work.  I did, however, get my long-overdue BFR out of the way Friday night, so at least I’m legal to fly again. (which is goos, since I’m planning on flying home to NC for Christmas next weekend…)

Anyway, nothing really complex happened today.  I’d already back riveted the trim doubler in place, and gotten all the stiffeners on one side of the left skin, save for the two aftmost rivets on each, which required a helper to hold the skin out of the way.  Really, I should have waited for help for all this; the rivets I shot solo last weekend were frequently not my best work.  I guess aligning the rivet gun, holding the set in place, and trying to hold the skin out of the way while squeezing the trigger was a little too much task overload.  Today we got right back to work shooting those aftmost rivets I’d skipped before, then went straight to work on the other side.  This is also a nice time to have a helper, when you’re dropping all those rivets into the skin holes, taping them in place, and so on.  We got through the remainder of the stiffener riveting in just over an hour.

Next was bending the trailing edges.  I took some time to review the procedure here before starting.  This is one of those times when the construction manual isn’t much help.  It basically says “Construct a bending brake to bend the trailing edges.  After bending, check for straightness with a good straightedge.”  So I went back to my post on bending the rudder trailing edge.  That gave me some good insight on how I did it before, but I wish I’d taken pictures of the rig.  I’m fairly certain I didn’t do it the exact same way this time.

But whatever, I got them bent, things are nice and straight, and it’s time to move on to working on the skeletons.  I’m going to try to get back out in the garage in the evenings after work this week; I haven’t done any weekday work in ages, and building weekends only will take me an eternity. (especially with the short weekend work day I’ve been doing)

The bending brake setup.  Two clamps hold the brake to the bench, while two more clamps hold the skin in place on the brake.

Checking for straightness

The finished skins

I’m going to have to get a heater for the garage really soon.  Luckily it was quite warm here today, and so it remained nice outside well into the evening, but that won’t last.  That, in turn, is going to be a concern if I intend to keep trying to put in shop time in the evenings after work.

Anyway, my first order of business tonight as to rivet the nutplates onto the trim reinforcement plate.  The instructions don’t specify to do this now, but it seemed to me that it’d be easier to rivet the nutplates on now as opposed to after the reinforcement plate was attached to the skin.  However, ever mindful that there might be a good reason to wait, I read all the way through the elevator instructions.  At no point did I see them specifically say to rivet the nutplates on, so I presume this is one of those little details that they leave to the builder.

Then it was on to dimpling the skins.  Nothing to really write home about here; it’s just dimpling.  I finished by wiping the skins down with acetone before putting them away for the night.  I learned back when it was hot that leaving sweat on the skins can make the alclad coating look nasty.  I’m not sure if it’s actually damaging to the skins or not, but it seems to smart to play it safe; so I’ve made a habit of always wiping the skins down after a shop session.

I probably won’t be able to get to back riveting the stiffeners until this weekend.  Tis the season for holiday gatherings; I’ve got mine tomorrow night and Josie wants me to come to hers Wednesday.  Thursday night we’re going to Cirque do Soleil, and who knows what might be going on Friday.

A beautiful baby trim reinforcement is born: