Section 15 – Wing Ribs (redux)

10/20/09 – Back to work.  Spent the day cleaning, tidying, and re-organizing the shop.  More needs to be done, but it was a good start.  Sat down and re-read the plans from start to finish, just to refamiliarize myself.  Pulled my dust covers off of the work-in-progress.  Reviewed my completed pieces for correct assembly and to assure myself that I had completed all of the steps prior to the restart point.  Total: 6hrs.

10/21/09 – Spent a few hours reviewing the alodine and priming decisions that I made last year.  Decided to go a different route (see “I’m Back, Baby” post below), so I went out and bought some rattle can primer at the local Napa.  I washed all of the main and nose ribs in Dawn, rinsed, and set aside to dry.  Fluted the main ribs per the plans.  Yes, this was skipping forward a step or two, but they were bothering me…sitting there all warpy and twisted while the nose ribs were so straight and happy.  I crimped and tweaked them into line, like their leading-edge brethren.  Fear me, ribs.  Tomorrow I will be proceeding with the steps following the fluting of the nose ribs.  Specifically, dimpling and installing nutplates.  Mom is flying in tomorrow, so I may or may not get to priming, match-drilling, etc.  Total: 3hrs.

10/26/09 – Back from a very nice trip to Vegas.  No gambling, but plenty of good food.  Sat down with the nose ribs and went over each one with a discerning eye and finger, looking for any additional deburring or pre-paint prep to be done.  All rib scallops were rounded out.  All that’s left for pre-prime prep is the dimpling and final drilling for the nutplates.  Note that I will be lightly priming these ribs due to the amount of scuffing and scratching that I inflicted on the ribs last year (when I fully expected to prime everything).  This has the added benefit of removing any minor surface corrosion and oxidation which may have accumulated over the last year.  Total: 2.5hrs

10/27/09 – My first “oops” of the restart.  Began to drill out the center hole to #19 for the nose rib nutplates.  My electric drill was in the house, so I grabbed a handy (low-speed) air drill and began to drill out the pre-punched holes.  No dice.  For whatever reason, the holes came out funky and oblong.  Luckily, this particular rib had a couple of identical brothers, so I found my power drill and grabbed one of the duplicate ribs.  Second time was the charm.  Now I just need to call builder support and find out if I can use the oops rib or if I need a new one.  Then I realized that my 3/32 dimple die set has disappeared sometime in the last year (really?  now where the hell did that thing go?).  So that’s a second call tomorrow…this one to Avery.  And, finally, my shop (which is a tent on my pool deck) suffered catastrophic failure in a huge windstorm last night.  The walls are fine, but the roof simply disappeared.  Well, at least I have something to do while I’m waiting for my dimple dies…

10/28/09 – Ordered the new dies from Avery.  Grr.  Changed the shop configuration to better suit actually building vs. idealized building.  Bought the new shop canopy.  Called Van’s to confirm that my botched holes in the rib webbing is a non-issue.  Confirmed.  Told me to deburr and ignore.  Done and done.

10/29/09 – Took the detritus from the reconfig to the dump.  Put up the new canopy.  Re-started my pilot training (approx 36.5hrs in, just need my long cross-country and a few more solo hours and I’ll be eligible for my check ride).  First flight in about 1.5yrs went veeeery well…until the landings.  Ouch.  Combo of a new instructor with new input plus rusty skillset (with a touch of gusty crosswind) led to two really ugly landings.  Bah.  Going back up tomorrow for another refresher and we’ll take the plane over to my local deserted international airstrip (rated for the Airbus 380 with virtually no traffic)…10,000×200′ of concrete-y goodness.  Taking the un-level, narrow, constrained home strip out of the equation should help me focus on putting the wheels on the numbers again.  Jeez, I USED to be good at this landing stuff

10/30/09 – Still waiting on the dimple dies.  Skipped ahead just a tad and match drilled two main ribs with the rib doublers.  Finally, something on the re-start went smoothly.  The two main ribs were match-drilled and deburred without incident.  Flew another hour in the Piper today.  It seemed to go much better than yesterday.  I’m regaining my situational awareness and getting comfortable with the engine and flight instruments.  Made several landings (at my home airport, no less) which got increasingly better.  Nothing like my old standards, but certainly getting there.  I should be soloing again after next week’s dual flight.

11/1/09 – Lots of progress today.  Hung two fluorescent shop-lights, which are a fantastic upgrade from my old lighting solution, which was a halogen job spotlight.  Dimpled the nutplates and 3/32 rivet holes on the three nose ribs per plans.  Wet-sanded out all scratches on the nose ribs and hung them up to air dry.  Fluted the three remaining unfluted main ribs.  Deburred the lightening holes on all main ribs.  Match drilled the four designated main ribs with the flaperon hinges and hinge plates.  Deburred the match-drilled holes.  The plan for the week is to get all ribs primed.  Before priming, some main ribs need additional deburring, and my HVLP gun is leaking in a fluid-delivery line which will need fixing.  We’ll see how much work I can get done during the week, now that I’m back at my full-time job.  The new shop lights were very, very nice.

11/2/09 – Short night.  Downloaded the plans revisions to date (my plans were o-riginal), printed them at the local Kinko’s and put them in my 11×17 binder.  Only one revision affects a step that I’d already completed (Ch. 13, changing an LP4-3 callout to LP4-4).  Since this revision is not classified as a Service Bulletin, I won’t be replacing my original work.  Inspected the flaperon hinge brackets.  While I’ve gotten the O-K from Van’s on the slight gap in the bracket, I want them to take a look at the double-countersunk flush rivets around the bearings.  The shop head stands proud of the surface.  So the question is, do I leave them alone?  Shave them?  Drill them?  Replace the brackets?  Dunno.  I’ll take some more pictures and send them off for builder support input.  Deburred about half of the remaining Main Ribs.  I have to say that I am mooooore than ready to be done with the ribs.  It’s odd.  I don’t mind deburring, cutting, filing, prepping, etc.  But the ribs just suck balls.  There’s too many of them, too many nooks and crannies.  Grrr.  I am very much looking forward to moving on from the damn ribs.

11/4/09 – Good news from Ken Scott at Van’s…the shop heads on my countersunk rivets (flaperon hinge brackets) are A-OK.  His email has been filed in my builder’s log.  Did final deburring on the remainder of the non-match-drilled main ribs.  I’m keeping the match-drilled parts segregated to avoid issues.  While they are marked for identification, I will be MEK’ing soon, and that will take the Sharpie right off.  Better to just keep them separate, I think.  Tomorrow I will debur the match-drilled main ribs and start the final pre-primer prep.  That prep will consist of cleaning with Dawn, rinse, wipe with MEK, scuff with scotchbright, MEK, alumiprep, dry, spray.  But that’s tomorrow.

11/5/09 – Abort Abort Abort.  Started my cleaning process and quickly realized that my organic fume respirator had deteriorated over the last 12mo’s of inactivity.  I made it about 5min before I realized that the respirator was shot and I bailed for the night.  Home Depot trip tomorrow will fix the issue.

11/6/09 – Picked up the new organic fume respirator and got back to work.  Washed, MEK’d, lightly scuffed, MEK’d, and hung up to dry all non-match-drilled main ribs.  The match-drilled main ribs are set aside to avoid confusion.

11/7/09 – Went to fly in the school’s Piper, but the pre-flight led to a cancelation.  Turns out that the oil is supposed to stay INSIDE the engine.  Which meant that the pool of fresh oil in the engine compartment was a bad thing.  Came home and prepped all of the nose ribs and two match drilled main ribs.  All that’s left is to prep the four flaperon hinged main ribs.  Hopefully I’ll get to prime most or all of the ribs tomorrow.

11/8/09 – Surprise trip to Disneyland with the kids meant no priming today.  I think that Wednesday (Veteran’s Day) is probably my best bet.

11/9/09 – Finally cleaned and scuffed the last four main ribs.  They have been set aside with their match-drilled mates.  I’ll stop by Harbor Freight tomorrow for an HVLP gun repair part and Wednesday looks doable for priming.  I had to take my shop digital camera in to work for a few days, which is why photos have been lacking.  I’ll try to get that back in-shop soon.

11/11/09 – First, I’d like to take a moment to give my thanks and support to our troops and our veterans.  The sacrifices of our military, their families, and (far too often) their survivors cannot be overstated or overappreciated.

Today was big.  I tried to use a new HVLP gun with my Stewart Systems primer on a few main ribs.  It just didn’t work.  The paint came out in splatters and globs, leaving a corrugated and over-painted look and feel.  Scratch that idea.  Time for Plan B, which was the Napa 7220 rattle-can primer.  I decided not to sand down the four test main ribs, but sprayed a little of the rattle can primer over the top for the sake of consistency.  Then I started to prime with the 7220.  Genius!  The priming went quickly and without a hitch.  I was very happy with the look and feel of the primed ribs.  They seemed very airplane-y.  I was finally able to install the (primed) nutplates on the three nose ribs and the rib doublers on the two main ribs.  And that, ladies and gentlemen, was the end of my year-long rib-prep process.  Hallelujah!  I have learned that I much prefer the “building” aspect to the “preparation” aspect of this process.  I have also learned that the preparation is at least as important, if not moreso, as the building.  Regardless, I’m freaking ecstatic to be moving on from the ribs.

I pulled the left spar off the sawhorses and put it up on the work surface.  I installed all of the main ribs per plans.  I installed the rear spar per plans, including the match drilling and LP4-4 rivets on the inboard main rib.  I moved on to the nose ribs, but didn’t quite finish.  After a couple of rivets on the third nose rib, I realized that I was using the wrong rib (trimmed forward and aft, rather than just aft).  I also realized that it had been a very long, productive day and I was pretty much done.  Ten minutes of cleanup later and I was soaking in the hot tub with a beer.  Progress!

11/12/09 – Oh crap.  I replaced the mis-installed nose rib and continued moving inboard with the nose rib installation.  As I began to install the untrimmed nose ribs, which requires the riveting of the aft rib flange to the spar, a minor problem arose.  The aft flange rivets were just a tad hard to seat, but a little force got them in.  Then I got to the forward-trimmed nose ribs.  Now the aft-flange rivets simply won’t seat in the spar.  I looked closely and found what appears to be a manufacturing defect with the spar.

A word of explanation, for those who don’t have a spar to look at.  The RV-12 wing spar is a u-shaped length of aluminum.  At the wing-tip, that spar is unreinforced.  As you get closer to the inboard end, there are additional layers of thick aluminum sheet laid on the bottom of the u-shaped spar and riveted into place.  At first there is one additional sheet, then a second, and finally (if I remember right), a third.  So, ultimately, the “web” of the spar is four layers thick at the inboard end.  In several places holes have been drilled through the layers of the spar to allow for the installation of rivets.  Those rivets are used to hold the nose ribs in place.

Unfortunately, it seems that the layers of the spar got misaligned by just a hair sometime after the holes were drilled.  The misalignment is virtually invisible at the outboard end, but is quite noticeable at the inboard end.  In fact, I noticed that some of the holes were obstructed when the wing kit was delivered, but simply didn’t think about it being an issue.  Ack!

I have sent an emergency assistance request to Van’s with a description.  My possible solutions include using an awl to try to realign the spar layers, but I simply don’t believe that that could work.  I could drill out the rivet holes to the same rivet size, but that would simply leave an elongated hole in the misaligned layer, which seems to be the main spar itself.  I could drill out the rivet holes to the next size up, but I’m afraid of compromising the minimum edge distance rule on the nose ribs.  Finally, I could drill out all of the installed ribs and wait for a new main spar.  Ugh.  We’ll see what Van’s has to say.

And of course, I don’t have my camera tonight, so pictures will wait for tomorrow.  boooooo.

11/13/09 – Sent off an email to Van’s builder support regarding my left spar issue.  Ken Scott got back to me and requested page/drawing #’s and photos for reference.  I provided those around noon and haven’t heard back.  I’m not taking silence as a good sign, but we’ll see.  I’ll but the left spar to one side and start on the right spar tomorrow.  The right spar seems fine upon inspection.

It's subtle, but you can see the mis-alignment in the rivet holes.

 

Left wing skeleton at time of defect discovery.

11/14/09 – Set the left spar aside and started on the right wing skeleton.  Installed all of the main ribs and rear spar.  Started on the nose ribs, but was called to daughter duty and never got back outside.  Went for another lesson.  I’m done with all minimum requirements, but for the long solo x-country and another .8 hours of simulated instrument time.  My slow flight needs work, too…

11/15/09 – Doh.  I just can’t win with this Section.  Installed the remainder of the nose ribs, then double checked my work (as usual).  Realized that I had put the inboard-most rib on the wrong side of the attach angle.  I punched and drilled the rivets, elongating two of the rivet holes in the rib (the attach angle is fine).  So I won’t be moving onto skinning the right wing while I wait for a solution on the left spar.  Booo.  I’ll call Van’s tomorrow and order a replacement rib, nutplates and rivets (just to be on the safe side).  Looks like I will start assembling the stall warning assembly for installation once the left spar is sorted out.

11/16/09 – Well, turns out that I need a different countersink to do the stall warning, so that’s on hold, too.  I stayed home with a sore lower back today, anyway, so that makes for a good time for a break, anyway.  I ordered a replacement nose rib and hardware from Van’s, ordered a new countersink head from Avery, and went to the chiro.  In the meantime, Ken Scott gave me the solution to my spar problem.  If I can get a #30 cleco into the mis-aligned hole, then I can drill the hole out with a #30 drill and rivet as usual.  He cleared this with Engineering (well, it was their solution, apparently), so I’m fine with it.  I will make a note to check the right wing nose ribs carefully on my annuals, but I’m comfortable with the solution.  I took a brief walk out to the shop and did the cleco check.  Even the most occluded holes took a #30 cleco, so it looks like I’m good to go.  I’ll probably finish up the left wing skeleton tomorrow and the right one on Wednesday when the parts come in.  Well, maybe Thursday…the local EAA meeting is Wednesday night and I’d like to start attending.

11/19/09 – Well, the sore back had me sidelined for a few days.  To make matters worse, I missed the EAA meeting due to a scheduling misunderstanding.  Doh.  In the meantime, the replacement parts came in from Van’s and the countersinks came in from Avery.  So I spent the evening re-doing the nose rib, including trimming, dimpling, and deburring.  It still sucked, even to do just one rib, but I noticed that Van’s has significantly (but almost imperceptibly) improved their rib stamping process.  All of the scallops are radiused and curved at the thickest part of the flange, whereas they used to be somewhat squared off at that point.  More impressively, all of the corners are now stamped out radiused.  I’m impressed and freaking jealous.  There was actually a significant amount of time spent filing a radius into numerous square corners on each of the 50+ ribs.  But it’s great news for later builders.  I also countersunk one of the plates for the stall warning per plans.  I deburred and prepped the two large-ish aluminum brackets from the stall warning chapter (that I don’t know the name of).  Tomorrow I will be cleaning and priming all of these parts so I can finish up the wing skeletons and move on to skinning.

11/20/09 – Cleaned, etched, and alodined the replacement nose rib.  Watched the new Star Trek movie with my wife.  This weekend should see the end of Sections 15 and 16.  Of course, I’ve thought that before…

11/22/09 – Section 15 is DONE.  Whew.  I spent a little time in the morning priming the rib (and stall warning parts), then I riveted in the nutplates on the replacement rib.  In the afternoon and evening I finished up the left and then right wing skeletons.  I should be able to get the stall warning installed before Thanksgiving, and I’ll also use the time for a tech inspection, if possible.  I’ll post some photos in this section when I get a chance.

I’m Back, Baby

Good lord.  Somehow a short break from the plane factory turned into a year hiatus.  How did that happen, one might ask.  I know I sure did (ask, that is).

At first I thought that I’d lost my mojo.  But that wasn’t it.  I still had the itch to get out and build all year, I just couldn’t organize or motivate to get out to do it.  Next, I blamed my work.  But while it is true that this was an incredibly busy year for me, there were still down times that I did not take advantage of.

So, when I leveraged my early-year productivity into a one-month vacation (all of October), I resolved to figure out what was keeping me from the Factory.  The first two weeks+ were spent out of state with the family, but now the kids are back in day care and the wife is back to work.  So I went back out to the shop, dusted off my tools and parts, and re-read the plans from front to back.  Then I went over each step to make sure that it had been done (I purposely did not review this blog beforehand, to keep me from making assumptions).  That help me remember not only what I had accomplished, but also how I had done it.

I realized that I had just gotten overwhelmed with work, family, a huge mess o’ ribs staring me in the face, and an overly complex and environmentally questionable anti-corrosion scheme (specifically, the alodine).

So I took some time to reassess what I’m doing, primer-wise.  I have time at the moment, so I could power through my original plan, at least with the rest of the wing.  But I’ll be back to work before I know it and I don’t want to just get myself back in this same position next month (or next year, or whenever).  I need to build a plane that I’m comfortable with, but if I’m not building the damn thing my comfort level with it is irrelevant.

On the other hand, I’m not willing to ignore the safety, time, and money issues posed by corrosion.  So I will be priming all mating surfaces (as recommended by Van’s) using (for the moment) rattle-can Napa 7220 self-etching primer.  I will also prep and shoot any area which has lost its Alclad via mishap, deburring, scratches, or whatever.

This is also the time for me to leverage the power of EAA.  Redlands has an EAA chapter, and I’m just down the road from the very capable folks at EAA Ch.1 at Flabob in Riverside.  I am committed to join my local chapters and get their expertise into my arsenal.

It’s time to get this show back on the road.