Joshua’s RV-9A Project

Not a whole lot of productive shop time today, but I was able to cross a couple things off the list: drilling the gussets which fix the tailcone bulkheads to the longerons, and installing the static ports.  I chose to proseal the ports in place (after removing a circle of primer), and clamped them while the proseal sets by using a large socket, with the drive hole placed over the protruding port.  I’ll give it a few days to set up before removing the clamps.  I did move the ports forward by about 3/16″ from the suggested location, due to interference between the flange of the port and the flange of the bulkhead.

Other niggling items: I reversed the direction of the rudder cable snap bushings in the 706 bulkhead, so they are inserted from the tailcone, which is accessible via the baggage wall, rather than from behind the riveted-in-place aft baggage side panel.  I’ve read that you need to remove the snap bushings in order to squeeze them a bit to allow the end of the cables to pass through, and this will allow that removal to happen.

I also happened to notice that two rivets were never set in the bottom of the 706 bulkhead, at the very bottom of the tunnel.  Those will not be fun to get at now (they should have been set before the bulkhead was installed in the tailcone…not sure how they were missed!  They will require an offset set and some contortions, but should be doable even if a pain.

Finished riveting the tailcone assembly, easy enough.  Then, started to disassemble the center section in preparation for the replacement of the right side pieces.

Riveted the two aft bulkheads to the tailcone skin, then clecoed the entire tailcone together.  Set a rivet at each bulkhead/stringer/skin junction (so, 4 places per bulkhead) before flipping the tailcone upside down on sawhorses for riveting.  Allison graciously drove all the bottom rivets I couldn’t reach solo, while I bucked from inside the tailcone.  After that was done, we flipped it back right-side-up, and I continued riveting; ended the night with about half of the right side done.  Should be able to finish this up tomorrow night.  Space in the shop getting rather tight now with two cars, garden tractor with snowblower, mower deck, generator, wing cart, workbench, and tailcone all competing for floor space…

Etched and primed the stiffeners and skins of the tailcone, plus some touch-up on bulkheads where primer had been scratched during the fitting process.  Now ready to reassemble and rivet.

Dimpled the tailcone components; they are now ready for etch & prime, but I am essentially out of primer. Also drilled and dimpled the #8 screw hole that will eventually hold the sleeve for the rudder cable in place as it passes out of the tailcone.

Ordered more primer and etch solution from Stewart Systems, which will hopefully arrive later this week, along with a boxful of Scotchbrite pads and some other assorted items: 1″ deburring wheels and the like from Cleaveland Tool, just down the highway in Boone, IA.

Trying to decide whether to join in on the group buy for Andair boost pump/filter/mount assemblies, which could save 12% or so off regular price, though I won’t actually need those components until later…and the possibility of them having an Oshkosh pump/filter/valve deal again this summer as they did last summer?

Finished drilling the J-stringers, then match-drilled the rest of the holes in the tailcone. Flipped it upside down to drill the bottom, rather than crawl on the January-cold cement.   Then it was time to take it apart again, and let the deburring begin.  Ran through the bulkheads, stiffeners, and skins, leaving them ready for dimpling.

Finished clecoing the tailcone together — bottom skin, side skins, bulkheads, stringers, and the aft tailcone skin.  This last part is the trickiest, and required a couple fittings to get it satisfactorily in place; even then, it’s not perfect, but some of the holes that attach it to the side skins & J-stringers are slightly off as you move aft.  The J-stringers are not pre-drilled, so there’s no issue there, but some of the other holes may become slightly ovalled; I’ve read of others dealing with this frustrating issue by just living with it, and/or moving up to 1/8″ rivets.  Works for me; the worst holes (aft-most) are only out by a max of 1/2 diameter.

Began fitting the J-stringers to this skeleton by drilling every 4th hole and placing a cleco…will come back in the next session and do every second hole, then go back and drill the remainder.  I did make a little block that made the drawing of the center line easy–one thick piece of cut-off bar stock, with a thin piece attached to it at a right angle with a cleco clamp.  Drill a #55 hole (just the right size for a fine-point Sharpie) at the required distance, then slide the whole thing down the length of the stringer to be marked, holding the Sharpie point through the hole.  I can’t remember where I got this idea from awhile back, but it works a charm.

Bought a third sawhorse to match the two I already had, saving me from buying a whole set of three.  Upon confirming that it was the same height, how could I resist setting the bottom tailcone skin on it and clecoing in a couple bulkheads?

Finished final assembly on the bulkheads by riveting the area around the pitch bellcrank on the baggage bulkhead, and bolting the seatbelt anchors in place.  I did realize, looking around the web later on last night, that I riveted the reinforcing angle to the F-728 channel prematurely — when the manual said “leave the 728 channel clecoed for now,” I took that to mean that the 728 assembly was to be clecoed to the bulkhead until later.  This is indeed the case, but they also want you to leave the angle off; looking forward in the manual, this appears to be for better access to buck some rivets, though I’m not entirely sure.  Since this piece isn’t permanently riveted in place for some time yet, I can always pull it and drill out the couple dozen rivets holding it together.

I do rather like the warm dark brown of the interior paint…just cheap Rustoleum Hammered, Dark Bronze color.  I was originally intending something lighter, but this was available, priced right, and Allison chose the color from the various options.  It’ll definitely guide upholstery color choices, and perhaps even affect exterior paint color, but that’s all fine.  I’ve seen pictures of both light and dark interiors.  I like the way the rivets look against the dark paint as well, which is why I’m going to the effort to paint the pieces before assembly.

Cut the J-stringers to length, and trimmed the ends to fit the bulkheads…this area is a bit confusing, since the plans show an aft trim detail, but no forward detail…the manual says “trim ends.”  Holding things together as they’ll eventually go, it’s clear that the forward ends need to be trimmed as well.  (Smitty’s site concurs.)  A cutoff wheel in the Dremel makes quick work of the cuts here, and a quick debur of the trimmed ends leaves us ready to begin assembly of the tailcone.  (Ok, there is one more middling task–to draw a centerline on each of the J-stringers.)

After building the priming table and cleaning up the shop, I needed to get the longerons out of the way to make space for priming…why not bend them too?  I had to move the vise to the main workbench, but the bending of the longerons went fairly easily using the “Orndorff method.”  The only glitch was that there is some minor scratching of the angles, despite having padded the vise jaws with 2 layers of rubber drawer liner, plus masking tape–so that’ll have to be smoothed out.  Fitted the canopy decks to the longerons at the appropriate place, and drilled them together before setting them out of the way…at least as out-of-the-way as you can get 15′ pieces of angle with odd bends in them.