Joshua’s RV-9A Project

Sprayed interior color on most of the batch of parts — the side skins and longerons remain.  I will pick up a quart can of the paint to do the side skins, as they would be rather tedious to do with a rattle can…

Etched the skins and longerons, then shot primer on all the parts.  Interior paint later this week, and with any luck, final assembly can begin on the weekend.

Etched all the fuselage components that are done to date, except for the side and forward bottom skins, and the main longerons.  Those are big enough that they really need to be done outside (the etch solution eats the concrete floor, and they’re too big to fit in the big plastic tray I use for etching parts); we’ll see if the weather is good enough tomorrow to get it done.  Should be able to get the priming done this week.

After tiring of etching, I thought I’d look at the install of the crotch strap brackets.  This is where I discovered a dormant screw-up that I was previously unaware of.  Turns out that when I initially fit the seat ribs to the center section, I got the inboard pair of F-916 ribs reversed.  That is, the inboard F-916-L goes on the right side, and vice versa.  Unlike some other parts of the plane, it’s completely possible to reverse these with no ill effects–the seat pans, bottom skin, and everything else all fit perfectly, so nothing screamed “wrong!”  Until I held the crotch strap brackets in place, when it became very evident what had happened.  The space between the ribs that are spanned by the bracket is about 3/4 of an inch too wide.  Since the center section isn’t yet attached to the tailcone, access to drill out and re-rivet these ribs isn’t a problem, so I drilled both out and put them in the correct orientation.  Easy enough, except for one thing: the 3/16″ holes that were match-drilled from the main spar, where AN3 bolts are inserted, are not in alignment with the line of rivets that runs down the forward flange of the ribs, but rather offset by a small amount.  This means that when the already-drilled ribs were flipped into the correct orientation, those 3/16″ holes are out of alignment by about 1/2-diameter, which would result in ovalled holes if drilled.  I’ve sent an email off to Van’s asking their advice–my guess is that they’ll say it’s fine, put in the bolt and move on, since that rib is also held in by a bunch of rivets.  But better to ask…if the ribs need replacing, it should be easy to do that, too…for $17.73 apiece, plus shipping.  Sigh.  I feel like I’ve made several stupid mistakes lately.

(The ribs in question are the third in from each side on the drawing — the inboard “F-916-L/R outboard seat rib”.  Marked by the clecos on the second photo.)

Went to the shop after fixing the garage door opener (new drive gear & bushings have it running smoothly again) with the intent of figuring out some antenna doublers, thinking that it would be a good idea to install them while access to the fuselage is easy for dimpling, deburring, and riveting.  Stood around staring at it for awhile, pondering, and made no progress on that — wondering if now is really the time, or not.  My proposed list of antennas:

• VHF Com 1 and 2 (Comant CI-122 bent whips): install under removable portion of seat pans, behind wing spar, left and right outermost bays of fuselage
• VOR/LOC/GS (Comant CI-157P or CI-158C “cat whiskers”): bottom of tailcone, just behind fwd edge of aft bottom tail skin
• Transponder (DeltaPop): near centerline of tailcone, somewhere aft of F-706 bulkhead [must be +3' from transponder itself]
• ADS-B (DeltaPop): right side fwd fuselage, near front fuel vent [must be +4' from transponder antenna]
• GPS (whatever 430W specifies): top side of fuselage aft of F-706
• GPS2, GPS3 (?): under cowling or aft canopy window?
• ELT (whatever is specified): undecided, perhaps top of fuse or along roll bar
• APRS (VHF com or Loran antenna?): undecided, perhaps opposite of ADS-B, or in a wingtip

Lots of stuff to think about.  The two of these where access would be most restricted in the future would be the transponder and the VOR, as they are aft of the cabin area, and perhaps the VHF comms.  I’ve looked all over the web and seen many different ways of mounting antennas: some use no doubler, some use a “floating” doubler secured only by the mounting bolts of the antenna itself, some rivet a flat doubler to the skin, some use a flanged doubler riveted to the skin, and some tie a doubler into nearby structure (either with or without riveting to the skin as well).  The latter ones seem sturdiest, but are they overkill?  I’m probably making this far more complex than it needs to be, but it seemed that this would be the ideal time to put these in, if they were to be riveted to skin and/or structure.

With all that indecision rolling about, I found something easy to do, even though it’s not needed for awhile: I laid out and cut the lightening holes in the seat back supports, and marked their flanges for trimming.  And, I drilled a 1/4″ hole in the left side of the 705 bulkhead, just under the longeron, for routing of the static line.  Whee.

Finished the final deburring on the side skins, and dimpled the three skins with help from Allison.  Fuselage parts are now ready for priming, which will probably be next Sunday when I next have a large block of time to spend.

Countersunk the main longerons, and deburred all the drilled holes in the side skins.

Crossed the 700 hour mark tonight, as well.

Deburred and dimpled the tailcone assembly and center fuselage section; installed the three nutplates on the outboard seat ribs.  Deburred the main longerons and marked them for countersinking.

And, received a package from England in the mail today — the Andair fuel pump and filter kit I bought on the VAF group buy has arrived.  Looks to be a solid piece of kit.

The deburring continues…lots of scotchbrite, filing, countersinking, and hole deburring.  Good progress on the pile of parts, but the longerons and tailcone remain, as do the side skins.  I’ll also have to pull the seat pans off to deburr the inside of the outermost seat ribs, which were match-drilled from the side skins.

Finished up the list of remaining tasks on the fuselage: drilled the ends of the floor stiffeners to the firewall & center section angles, filed the gear socket hole cutouts into the center section, cut the holes in the wing root area for the fuel & electrical pass-thrus, fit the baggage wall structure and side panels, and match-drilled any holes that hadn’t previously been done.

With all that done, it was time to take the fuselage apart once more for the deburr/dimple/prime dance.  I think taking apart the brake pedals took nearly as long as the whole fuselage–and I only put in half the bolts!  I deburred all the solid angle pieces, the small parts, and some of the complicated stuff (ie, anything with tabs and flanges and little bits that need filing and can’t be done with the scotchbrite wheel…).  Tomorrow I can hopefully finish up the rest of the deburring; there’s oodles of countersinking to be done as well.  It’ll be several weeks now before I can get back to the project for longer than an hour or maybe two.

Fit and drilled the four floor stiffeners to the forward bottom skin.