Joshua's RV-9A Project

No, it’s not the pre-landing checklist, it’s today’s work session…  In the morning, I was able to get the riveting done on all the pieces that were recently primed: the forward tunnel covers, fuel valve cover, and flap parts.  Many nutplates were installed, and the flap assembly was clecoed in place for now (still waiting on the missing nutplate to arrive for final install).

The evening session focused on the next step: gear towers.  I ordered a .311 reamer from Avery Tools, which arrived this morning, and was shortly put to use on the gear legs: first, I cleaned the inside of the towers and the outside of the gear legs with a scotchbrite pad, then wiped everything down and coated with some light oil (I just used pneumatic tool oil which I happened to have handy).  This allowed them to slide together with relative ease…a couple taps with a rubber mallet and everything was aligned.  With Boelube on the reamer and a dab inside the pre-drilled hole, it was easy to ream the hole to size.  Disassembled and deburred, and the legs were set aside for later use.  The gear towers went into the fuselage, after trimming away a bit of the aft end of the outboard floor stiffeners to allow clearance for the mount.

Of note is the brake fitting holes which were drilled back in the bottom skin prep phase…while the right hole aligned well, the left one was off by about 1/3 diameter, compared to the hole in the weldment.  Not a big deal, I just used the unibit to move it in the correct direction, large enough that the fitting could slip into place.  I also upsized the bolts along the top of the spar to -13A’s, which means I’ll need to order a fistful of -13A replacements…it just looked better, as the nuts have only about 1/2 thread showing with the -12′s.  This is apparently a common issue, and other builders have also upsized to the -13A’s, though Van’s says it’s unnecessary.  For ease of fitting the gear towers, the outboard snap bushing was also removed, and reinstalled after the towers were bolted in.  A long open-end or box-end wrench is a necessity here, to reach the nuts inside the bottom of the spar.

The next step was to drill the holes and install the fasteners along the side skins.  The 5 aft bolts are easy; they are drilled using the pre-punched holes in the skin.  The 2 forward holes are drilled through the skin using holes in the mount, one of which is tucked in behind a bulkhead flange and not easily accessible.  Following the lead of others, I used a #40 bit to drill through the bulkhead flange, then out through the mount and side skin.  I enlarged that hole from the outside to #30, then to final size for the AN3 screw, and countersunk.  The most difficult part of the operation is fishing the chips out from between the side skin and bottom skin…I made good use of the “chip chaser” tool, along with a thin steel ruler.  The left side is drilled, the right side will get done tomorrow.

(An aside: I watched an online EAA video last night about torque seal, and learned that I’d been doing it partially wrong…the torque seal is supposed to be applied from the nut, across the washer, to the base material, but not from the nut onto the threads…apparently it can damage the threads on later removal.  I’ve done quite a few with a stripe all the way from the base material to the threads, so if those need to be removed later, the threads will be inspected and replaced as needed.)

Disassembled the fabricated parts for the flap actuator, aileron trim, and forward tunnel covers.  Etch, rinse, dry, then prime everything, followed by spraying paint on the visible surfaces.

Went to drill the nutplates for the center bearing block on the flap actuator while the primer cured, and discovered that the one -3 single-leg nutplate that is needed is missing in action.  Searched all around, and looked at the parts list–it appears to be the only one of these (MS21051-L3) that is sent.  My theory is that it must have gotten caught inside the flaps at the bottom of the bag and tossed out with the supposedly-empty bag, as I don’t even have a drawer in the bin wall marked for it.  An 80-cent part from Van’s…sigh.  Forward progress may stop here for awhile, as everything I’m looking at doing is waiting on some part or another (gear mounts need a reamer, flaps need a nutplate, center tunnel covers need the boost pump doghouse, etc…)

Started out with some monkeying with the center tunnel covers–match drilling various parts, deburring everything, and modifying the fuel valve plate to remove the trim cable mount.  Done and set aside for paint and modification for the boost pump.

First fitting of the flap system today.  Lots of parts needed fabrication: brackets for the top & bottom of the actuator channel, mounting angle and plate for the motor, a bolt spacer, etc.  Drilled the end of the actuator arm for the safety wire hole, and also drilled the rod end, since you can then wire the rod end to the actuator, rather than around the bolt (a joint which rotates by design with each flap extension/retraction)…this method of safetying seems to be favored among builders, though I need to look and see just how they’re running the wire.  I tried it a couple ways and finally settled on one, though it still seems loose to me, so I will see what others have done and probably re-do it; safety-wiring is a brand new skill to me.

With all the pieces fabricated, it’s time to fit it together…first, the arm weldment is bolted in place and the center bearing block fit; this is bolted near the tunnel, so the aft tunnel cover must be notched to fit around the bearing block.  The actuator channel is drilled to the cross-brace, the motor mount drilled to the channel, then the side panels put in place to drill the rear channel, whose bracket was previously drilled for the floor screws using the tunnel cover as a guide.  (It’s not as complicated as it all sounds…)  The forward tunnel cover also needed to be trimmed a bit; the bottom angle needed a more gentle curve to nest into the brackets that hold the flap actuator channel, and the top piece was too long (I expected this, having left it a bit long intentionally to cut it for a good fit).

A few more things to wrap up (drilling nutplates, etc) and then I will have to do another batch of prep/prime/paint so some of these things can be installed.

Lots of stuff done today, mostly focusing on the cabin area: first, a thorough vacuuming session of the whole fuselage to remove all the shavings and other schmutz, then the seat pans were installed with pop rivets.  Then I added #30 drain holes just behind each of the rear fuselage bulkheads, and vacuumed again.  While I was back there, I riveted the aft end of the armrests, which had been missed previously.  I had the fuselage on its side again for most of today’s session…it’s not too hard to pick up the forward end and roll it by hand.  Also attached nutplates to the baggage side wall panels and clecoed them in, to get them off the bench.

Upper firewall gusset plates riveted in place…over half of these can be done with the squeezer, but I used the gun on the four forward rivets.  I may have been able to do them with the long no-hole yoke, but I’ve had mixed results using that on 470-4 rivets before; the extra flex in the longer yoke seems to make them more prone to tipping, rather than setting properly.

Fabricated the various parts for the manual roll trim assembly, and installed that temporarily.  This will come apart later for priming with the next batch, as my trial with the Preval sprayer didn’t go so well–the AFS primer needs to be thinned down quite a bit for it to successfully spray in the unit, and then it lays down extremely heavy, which causes puddles, runs, and poor finish.  I should pick up a few cans of Napa 7220 or GBP 988 for little parts like this…  After the roll trim assembly was in place, the forward seat pans were clecoed in.  (I did drill the roll trim handle as well, but have left it off for now to ease repeated removal/installation of the seat pans.)

Finally, fabricated the forward tunnel cover, which is made of a piece of .040 sheet and a couple pieces of Z-channel.  The sheet is bent to match the angle of the seat pans at the forward end, and the Z-channel is trimmed to fit the various angles and pieces it needs to clear.  A nutplate is installed on the seat pan to secure the forward end.  Easy enough…this too will come out for priming later.

The next step in the book is to install the various covers and such that go forward of the spar carrythru; I will skip at least some of that for the moment, since I don’t want to box myself in with the installation of the FI boost pump, which requires some modification to the center tunnel cover — I need to order those parts from Vans to rig this up.  That means the next big thing is the flap system…first moving parts of the fuselage!

Riveted the seatback hinges to the seat pans; these need to be done with the gun, so making a fixture out of 2×4′s and clamps helps hold things in place for easy access.  Also riveted the longeron/bulkhead gussets in place, easily accomplished with the squeezer and various yokes.  Also used a roll of emery paper to relieve a couple of the bulkhead notches that were rubbing on the longerons, and spot-primed.

Primed and painted the parts readied in yesterday’s etching session.  They’ll dry overnight and be ready for assembly tomorrow.

Deburred a pile of parts, and etched for priming: gusset plates, seat pans, baggage side covers, and so on.  Went to town to buy more cheesecloth for straining the primer, in the absence of proper paint filters (otherwise clods get in and clog up the gun, despite my best mixing efforts).  Should be able to shoot these tomorrow after work.

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.

Worked on a bunch of odds ‘n’ ends tonight:

• Marked and drilled the seatback attach hinges (hint: mark & drill one, then use cleco-clamps to attach it to the next and use it as a drill template), then drilled them to the seat pans.  Back-drilled the aft hinges for the rivets that attach to the seat ribs.
• Trimmed the necessary eyelets from the hinges.  First use of the bandsaw on this project…it really cuts the aluminum like the proverbial butter.  A little filing, a brush on the scotchbrite wheel, and they were done quickly.
• Removed the aft skins from the fuselage and set them aside to be prepped for primer and later riveting.
• Installed some snap bushings in the mid-tailcone, where I couldn’t reach earlier with the skins on.
• Squeezed the two forward-most rivets on the aft deck, which I didn’t do before due to their proximity to the bulkhead (which I also removed).
• Deburred the harness cable attach bracket holes in the longerons.