(page 21-07) Unhinged............                

After successfully match drilling the aforementioned seat back hinges, I proceeded to rivet them to the floor.  Unfortunately, I skipped one step -- removing two "eyes" from each hinge -- which must be done (obviously) before riveting (red arrows in the picture).  I therefore had the pleasure of drilling out 28 rivets in order to correct my error.  The band saw quickly removed the unwanted eyes and the ScotchBrite wheel (my new BFF) quickly deburred everything.  On the bright side, they were pulled rivets, which are way easier to remove.  I'm becoming quite the expert at drilling out squeezed or pulled rivets.

I'm longing to build some parts that the average person would identify as airplane parts.  Wings maybe?  The problem is this: Until all these parts spread around my garage coalesce into a fuselage, I don't have room to build wings.

(page 21-04) Little boxes..........                                  

The flaperon mixer assembly, pulley bracket assemble, baggage compartment ribs, floor ribs, etc., go together fairly easily with little confusion once I wrapped my head around the fact that some ribs labeled -R go on the left side of the airplane and some labeled -L go on the right side.  I guess they had a reason for doing this.  The discovery of this caused me at one point to think I'd made a massive error, but the pictures are quite clear about where everything goes.  Lots of nutplates to install, meaning lots of dimpling and lots of squeezing 3/32 rivets.  Things came to a brief halt on page 21-05 when reference was made to installing the autopilot bracket by referring to Section 39, which I thought I didn't have.  Turns out, a separate bag contains all hardware and instructions (Section 39).  Problem solved.

Real problems didn't materialize until page 21-06 where piano hinges have to be drilled for the seat back attachment to the floor.  My prior experience with drilling piano hinges was not a good one, resulting in a re-order from Van's.  Sure enough, the first hole I match-drilled through the hinge was off center (see picture).  The problem arose because the hinge is so far from the edges of the floor that it can't be clamped in place, and you can't see the hinge while drilling.  I solved the problem by sandwiching the hinge tightly between the floor panel and a 2x4 stood on edge.  Fortunately, I had an extra six feet (!) of hinge from my previous hinge misadventure.

(page 21-03) Baggage compartment floor...........                          

...yet another near disaster averted.  After reasoning out which holes required which of three dimple dies earlier, I somehow convinced myself that the dimpling of holes should have been symmetric left to right (it's not) and was ready to drill out approximately 30 rivets to correct my non-existent error.  Feeling disgusted, I took a break and went for a 20-mile bike ride, during which the increased blood flow to my brain caused me to realize I had done everything correctly the first time.  This project can be stressful.

After attempting to align rivet holes drilled individually through several relatively thick parts, it's often difficult (or impossible) to insert the rivet.  For the skin-to-rib holes, a 1/8th-inch drift usually lines the holes up enough to rivet.  For thicker parts (shown in the picture) this frequently won't work.  A chuck removed from an old drill (containing a #30 bit here) works well to twist the bit through the recalcitrant hole by hand.

(page 21-02, step 7) What wing spar?......                                

Step seven says "File the curved  recess of both wing spar receptacles to closely fit the rounded mating ends of the rear spar assemblies of both wings."  The problem is, contrary to what most people apparently do, I bought the fuselage kit before the wing kit, figuring that it was quite important to finish the fuselage first in order to accommodate my sitting in the fuselage, grasping the stick, and making airplane noises.  Little did I know that I'd need something from the wing kit in order to complete some task in the fuselage kit.  After my initial panic, I solved the problem by ordering the rear stub spars from the Mother Ship (parts shown on right) for the grand sum of $31.00.  Problem solved.  I'll simply delete these parts from the wing kit when I order it.  The plans say to identify the top of the receptacle by the flat spot machined there.  It appeared to me that both ends of the part had a flat spot, and I initially mis-identified the top and filed the inner contour to match the stub spar upside down.  Fortunately, the rivets only match up in the correct orientation, and I discovered my error.  Doubly fortunately, the contours still matched when I turned them upside down, so all was well.

I was delighted that the plans called for pulled rivets for these parts, so I broke out my favorite tool: the pneumatic rivet puller (shown at the top of the picture).  When the wings are attached, the stub spars fit into these receptacles and carry the torsional loads from the wings.  The wing spars (which, of course, I don't have yet) support all the bending, most of the shear, and none of the torsion load.  There's a similar stub spar at the front of the wing which I haven't encountered yet.

(page 21-02) My concerns about the long rivets....                                   

...through the massive and expensive center section channel were, for the most part, unfounded.  The operations called for in attaching the baggage floor to the ribs and center section did, however, require some careful thought, and offered ample opportunity for missteps.  In retrospect, the words in the build manual say exactly what needs to be done.  It just took me a while to believe the words.  Along the perimeter of the T-shaped cutout in the baggage floor, some holes require dimpling with #40, #30 or #19 dimple dies, and some holes need to be left alone.  Determining which was which was the issue.  The #19 holes, clearly labeled in the manual, are the holes corresponding to the center of a nutplate, through which a screw

will eventually be inserted.  No other holes corresponding to the center of a nutplate get dimpled.  The #40 holes are for the flush rivets attaching the nutplates to the floor.  The #30 holes are for flush rivets attaching the floor to the ribs.  There are a few other random holes whose purpose I don't yet know and which don't fall into the above categories.  All of the other #30 holes in the baggage floor are for round-head rivets which attach the floor to the ribs (requiring use of my favorite tool -- the pneumatic puller).

The pulled rivets which attach the floor ribs to the center-section aft bulkhead are required to have the manufactured head against the bulkhead, meaning the hand puller (the pneumatic puller won't fit) must be operated in the relatively narrow space between the fore and aft center-section bulkheads.  This was not fun, especially for the rivet closest to the channel web (shown).  This required use of one of the little wedges whose manufacture was the very first step in the construction of the kit.  The hole is so close to the bulkhead that the wedge wouldn't fit against the bulkhead without bending the shank of the rivet to about a 20-degree angle relative to the web.  Worked great after the swearing subsided.

(page 20-02) Fuselage center section...                      

A scary-looking piece considering how much it'll cost if I manage to screw it up.  It first had to be clecoed to the bottom skin to ensure proper lateral alignment of the fore and aft center section bulkheads.  The backbone of this piece is a massive (compared to every other piece I've worked on to date) aluminum channel with 3/8th-inch-thick flanges.  The aft bulkhead is clamped to the flange of the channel, and then 72 #30 holes are match-drilled through the flange, providing 72 opportunities to kill this piece and 72 stress concentrations as the channel fulfills it duty of supporting the bending and shear loads produced by the wings and landing gear.  My track record squeezing long rivets is not enviable, and if some of the holes are not precisely perpendicular to the flange surface, it's hard to get a good squeeze without bending the rivet.  Bent rivets, of course, have to be drilled out and redone, often leading to an enlarged hole, which.....well, you get the picture.  I started the drilling process with fear and trepidation.

Turns out I was worrying way too much about the drilling.  For each hole, I held a thick carpenter's square against the flat surface close to the drill bit, providing an excellent visual reference to the perpendicular.  I'm confident that all the holes are close enough to perpendicular, but I may change my tune when the squeezing commences.

I drilled and clecoed the holes shown in the first picture, then un-clecoed the bottom skin and layed the piece flat on the table as shown so I was drilling vertically downward.  This made the task much easier than I first imagined it would be.  The lesson I took from this is to buy the best quality drill bits available.  Some I got from an unknown supplier proved not up to the task.  The bits that came with the tool kit from Isham have been excellent.

Pilgrimage complete for 2012..........              

I recently returned from my 24th trip to Oshkosh; as usual, a sensory overload.  A week at the show is at once too much and not enough.  On the flight back (airline until the -12 is finished), I'm always sunburned, tired, and a bit depressed that it's over for a year.  Amazingly, there were over 500 RVs in attendance.  I saw at least eight -12s there and had some interesting and instructive chats with builders.  The picture shows all the -12 builders in attendance at a pre-arranged meeting.  Joe Arluck was nice enough to coordinate this, even having prepared name tags for all of us which showed real name, VAF name, airplane number, and home town.  At 5-11, 155 pounds, I'm feeling a bit mass-challenged compared to the others (I'm the one labeled AeroDog -- my name on Internet forums).  Maybe that'll translate into some additional speed and climb rate when I'm done, but they'll get a smoother ride in turbulence due to the higher wing loading.  ;-)  Almost hidden behind us is N412RV, the airplane responsible for hooking me on these delightful flying machines when I flew it two summers ago.

Regarding my recent assertion that I'm definitely going to paint as I go:  As anyone who knows me can attest, once I've made up my mind, I'm iffy.  After discussions at Oshkosh, I'm (at least for now) planning to finish the airplane, complete the phase one flight test, then fly it to a paint shop and pay a professional to paint it.  This will cost more but save time, and, at this point in my life, time is my most precious commodity.