Joshua's RV-9A Project

Built the flat table for aileron & flap assembly tonight…that sucker must weigh upwards of 100 pounds.  The top and bottom are half-sheets of 3/4″ MDF, and the structure is most of four 2×4′s, put together with plenty of screws.  It checks out flat with a 4′ straightedge, so I imagine it will serve the purpose.  Also reading up on the trials and tribulations of building the control surfaces on others’ build logs.

Back-riveted the stiffeners to the aileron skins, then proceeded with the assembly of the left aileron.  Clecoed the bottom skin in place, drilled the ribs, deburred and dimpled.  Then installed the bottom skin with the two “keeper rivets”, and clecoed the top & nose skins in place as described.  The nose skin puts a great deal of force on the aileron, and the trailing edge goes really wavy, but I’ve read this is normal.  Tomorrow’s task will be building the flat table for the driling & riveting of these guys, and I need to get some weights of some sort–sandbags or lead shot, I’m thinking–to hold the aileron flat to the table.

Allison helped out tonight, dimpling the aileron skins & stiffeners while I etched for primer.  After everything was dry, I went ahead and shot the primer–in a race with the setting sun–so the stiffeners are ready to back-rivet to the skins.

Back home after two-and-a-half weeks away on “vacation.”  Almost three weeks since I did any work on the plane, but I’m ready to dive into the ailerons.  To that end, I started out with the tedious work — cutting, shaping, and deburring the 28 aileron stiffeners using snips, disc sander, and scotchbrite wheels.

Next, clecoed the aileron spars together with the nose ribs, then marked and drilled the counterbalance pipes (after deburring the ends to remove the very sharp stainless steel burrs).  I cut a V into a scrap of 2×4 to make a holding fixture for drilling the pipe — slowest speed on the drill press, light pressure, and Boelube made easy work of the holes.

Put in the temporary rivets to attach the counterbalance to the nose ribs, and clecoed the ribs back onto the spar, then clecoed the end ribs in place.  I goofed when I was match-drilling the reinforcement plates, and drilled out a couple wrong holes, which were the two holes intended for -3 rivets on the left outboard rib.  I can’t see any reason why simply upgrading to -4 rivets won’t work there, or even oops rivets.  Luckily, I caught myself before I had drilled all four sets…just one set is big.

Identified the various top & bottom skins and marked the for left/right, top/bottom, inside/outside, then drilled the stiffeners to all four skins.  Finally, more tedious work — deburring the holes in all four skins and 28 stiffeners.  Finished up by edge-finishing the four skins, and scuffing the lines where dimples are to go.  The stiffeners & skins are ready for dimpling, prep, and priming.

Hit the ground running today and riveted on the flap brackets and associated angles.  Nothing major different than the left wing process; the only “problem” rivets are those three spar-angle rivets nearest to the top skin, but with added experience from yesterday, then came out passably.  One ugly “smiley” in that awful root-end rivet, but after yesterday’s lesson, I decided to leave it as-is.  After the brackets were in place, I riveted on the gap fairings, and the right wing is done.

Wrapping up, I vacuumed the aluminum shavings out of both wings, then went through them and spot-primed the scrapes and scuffs from the riveting process.  Torque-sealed the fuel tank bolts on the right wing (I had anready done the left wing while it was in the jig).  Bolted the bellcrank brackets in place on the right wing (the bottom bracket replaced by the Trutrak servo mounting bracket; I have left the top servo support bracket out for now, because with no servo, one end is loose in the air, and would be free to vibrate.)  Torqued and sealed the bellcrank bolts.

Spent some time at the end putting tools away, sweeping the shop, and re-organizing to fit two vehicles into the garage bays.

A solid full day in the shop ahead of vacation plans, which resulted in good progress on the wings.  Started out by etching and priming all the flap & aileron bracket parts, plus the gap fairings…a task made interesting by the afternoon’s weather.  I set the parts out on the priming table in the sun, and by the time I had loaded the gun with primer, it had begun to rain.  Inside with all the parts, and start to prime in an impromptu cardboard “booth”…  Soon enough, the sun was back and normal operations could resume.  Primed everything and set it aside to dry, while I worked on deburring and dimpling the #40 holes in the wing skins that attach the gap fairings.

Once the gap fairings were dry, I dimpled the skin attach holes there as well, then set about assembling the aileron brackets.  Had to drill out a couple rivets in two of the brackets when I realized I had misread the plans, and not countersunk for the installation of flush rivets in a few spots.  Oops…not a big deal to fix, though, and the brackets were soon assembled.  Installation onto the wing was relatively painless, the riveting being rather straightforward.

With the aileron brackets in place, I started work on the flap brackets, at which point I realized that I had never countersunk the holes where the skin dimpled nest into those pieces either.  Took care of that, and spot-primed as necessary.  I first installed the rivets that hold only the main piece of the flap brackets to the rib (many of which are squeezable), then went back and installed the bracket-spar angles, then the bracket-skin angles.  It feels more productive to do a whole set of related tasks while a tool (gun, squeezer, air regulator, etc) is configured for a particular situation, rather than having to constantly reset the tool.

The only real problem rivet was the 470 rivet at the root end, where the flap bracket attaches, as it’s a rather long (-9) rivet, and it’s close up to the skin, requiring the use of the double-offset rivet set.  A tool which I have never been satisfied with the use of.  It seems as if the double-offset allows the tool to “spring” and doesn’t transfer the energy of the gun into the rivet nearly as well as the straight or single-offset sets do.  After drilling the rivet out twice (I had distorted the manufactured head with the set), I had a hole that was ovaled in the top piece of metal (the rear spar doubler).  I decided to address that by making that rivet a flush rivet, same as the other two rivets on that row.  The countersink removed the ovalled portion of the hole, and I was able to squeeze the rivet with the 4″ no-hole yoke on the squeezer.  The bugger is still not perfect, but there are many other rivets in that area.  I’ll point it out to my tech counselor for his opinion on the next visit, as well.  Today’s lesson?  If the rivet is good enough, don’t try to drill it out (again!) in hopes of making it perfect…

All in all, the left & right aileron brackets are installed, and the left flap brackets are in.  After all that, it was a quick job to cleco on the left wing gap fairings and rivet them in place.  Only 2 rivets in the gap fairings require use of the gun (where they’re too close to ribs or brackets to fit the squeezer body); the rest are squeezable.  I love my pneumatic squeezer and longeron yoke!

Hoping to get the right wing to the same point tomorrow, then I should be able to roll the wing cart off to the side of the shop and move the fuselage kit out of the second garage bay, so we can get both cars in and secured during our trip.  Looking forward to watching the news out of Oshkosh this week, as well.

The task that never ends…  deburred & edge-finished all four gap fairings, as well as the #30 holes in the spar and ribs for the flap & aileron brackets.  Still need to deburr the #40 holes in the top skins, and dimple where necessary.  The pieces with the little radii, cutouts and such are the worst to deburr — you end up using several different files, including the set of miniature files, plus scotchbrite pads.  Still not as bad as those square corners of ribs, though.

Drilled the flap & aileron gap fairings to the skins and spars, then removed them from the wing.  Deburred all the holes on the components of the flap & aileron brackets, and finished the edges with files and scotchbrite wheel.  With time, luck, and perseverance, I might have all this stuff installed before we leave for AK on the 29th.

Aligned and drilled the flap bracket angles that were fabricated yesterday; lots of drilling, but easy enough, with a set of 12″ bits and an angle drill to use where necessary.  Clecoed on the bottom skins and back-drilled those holes into the angles as well, then removed the skins, and all the flap & aileron brackets.  These parts are ready for deburring and priming.  Finished up the session by clecoing the flap & aileron gap fairings in place.  They need to be drilled to the wing, then they’ll be ready for prep & prime.  This is the last batch of parts to prime & install before control surface fabrication begins in earnest.

No progress pictures, as the camera batteries are dead.

Worked on fabricating the flap bracket angles, using the hacksaw and bench sander.  Cut and shaped all twelve pieces in preparation for drilling.