Joshua's RV-9A Project

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.

Continued drilling the center section where I’d left off, until I realized I made a big mistake.  Turns out the F-904H doublers are not symmetrical — there are 17 holes on one vertical row, and 18 on another.  The left one had been clamped on correctly, but the right one was reversed; guess which I drilled first.  Sigh.  The recovery won’t be as bad as it could be, though; Van’s sells replacement center section side pieces, so all I need to do is drill out the 40-some rivets holding those onto the main piece, and replace, then re-drill with the 904H plate oriented correctly.  The only awful rivets to drill out will be those -14′s that hold the reinforcing bar in place.  I’m going to order some -22′s to have on hand for those, and just cut them to length as necessary.

Continued to work on the center fuselage by fitting the 705 bulkhead and the baggage ribs, followed by the bottom skin.  This requires some trimming of ribs to allow for wiring grommets.  I forgot to back-drill the seat ribs where they bolt to the center section, so that will have to come later.  Match-drilled the bottom skin to all the pieces, then fit the outer seat ribs and drilled them to the skin, followed by the baggage side ribs, another piece that needs trimming, plus the fabrication of little plates that connect them to the structure fore and aft.  Finally, fit the forward piece of the center section and match-drilled it to the skin.  Clecoed on the side plates before getting called away for the night.

Also tonight, crossed the 600-hour mark on the project.  Looks like the goal of finishing the tailcone should be easily reached before January is over.

To do list: drill bolt holes, figure out countersinking/dimpling of center section holes.

Having nowhere to go on the tailcone until more primer arrives, I went ahead and started on the assembly/fabrication tasks in the center fuselage.  The first task is to fabricate a set of four spacers from 1/8″ bar stock…done.  Then, you modify four of the seat ribs to allow space for the control column…done.  The next item is to install nutplates; this will wait until after priming, so I went ahead and drilled out the necessary holes for snap bushings, and clecoed the seat ribs (after fluting) to the aft piece of the center section, along with the requisite trimming of the two center ribs to make room for snap bushings.  Looking good…

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.)