Joshua's RV-9A Project

First thing on today’s agenda (well, after the dentist and barber) was rigging the elevators, which meant building the long pushrod that runs from the bellcrank to the elevator horns.  I looked at the plans and added 3/8″ to the pushrod length for fudge factor (easy to remove more, harder to put it back on…).  Cleaned up the ends and taped the fittings and rod end bearings in place, then set the total pushrod length to match the plans.  This turned out the be right one when I put it in the plane: the bellcrank was at it’s neutral spot, as were the elevators.  This is a moving parts moment, so I had to unclamp the elevators for a moment and move the bellcrank while watching the elevators move.  The pushrod was then removed and the ends marked and drilled, with the hole layout done on a piece of tape as a template.  I sloshed primer inside the tube and set it aside to dry for later riveting.

The vertical stabilizer was mounted next.  Since this uses the elevator up stop as part of its attachment, that needed to be fabricated and installed (odd that I could not find where the manual says to install this, but clearly it needs to be installed prior to fitting the VS, since it says to drill the VS to it).  Before installation, the VS front spar also needed to be trimmed at an angle to fit.  The installation required some careful, though not difficult, measuring to set the proper angles.  Clamp well, drill, bolt, repeat for the three locations where it is attached to the fuselage.  The tiedown bar differed somewhat from the manual, because I fabricated and drilled it to the aft bulkhead when building the bulkheads.  So rather than drilling the holes in the VS/bulkhead stack and then match-drilling the tiedown bar, I simply back-drilled the VS through the #30 holes in the bulkhead, then enlarged from the outside to 3/16.  This worked well, and the VS was momentarily removed to rivet the tiedown bar to the bulkhead.  To set the location of the front spar, which depends on getting the hinge brackets in a straight line, I ran some string through the hinges and used that as a guide.  I ended up with the VS spar on the back side of the attach plate, which the manual says is kosher.

With the VS attached, the rudder install came next…nothing difficult here, especially as the rudder had already been fitted to the VS during construction of the tail.  I did adjust the bearings for friction-free swing (when building the tail, it is difficult to get the VS rear spar straight, which it is now), and check to see that there was at least 35 degrees of travel on the rudder.

Final job for the day was fabrication of the rudder stops.  I’ve said this before, but I am very glad to have a bandsaw in the shop now, as it made fabrication of these angles pretty trivial.  I made the rear bit intentionally oversize, to leave a fudge factor for filing down when fitting.  I first fabricated the left stop and fit it to the fuselage, filing away until I hit the required 35 degrees of swing.  Then I simply created a mirror image part for the right side, again leaving some extra material on the rear face for filing.  These turned out nicely, and I’ve left them clecoed in place for now.

A couple pictures of the fuselage with the tail attached…  The book says this is a good time to fit the empennage fairing, but I think I will skip that for now and do it when I do the tips, to keep the glass work together once I’m set up for it.

First things first, a plumbing tweak.  I was stumbling around on VAF last night on a completely unrelated topic when I came across a thread about fuel vent routing.  Those lines that I was so happy with had to be adjusted, because I ran them to the top of the bulkhead at a 90-degree angle, which would later interfere with the mouting of the subpanel.  This post has a picture which illustrates the issue.  Not a big deal, I just removed the adel clamps on the aft vertical run, undid the bottom fitting, bent the correct angles at the top, then trimmed the lower portion of the line and re-flared.  The plumbing is really done now…I think.

Nextly, back to work on the aft end of the plane.  I finished drilling up the holes in the horizontal stab, then attached the elevators and fitted the counterweights.  The right elevator is a bit nose-heavy, while the left is almost dead-on balanced.  Supposedly, nose-heavy is the way you want to be before paint, since there is more surface area (thus more added paint weight) aft of the pivot point.  Clamped the counterbalances to the stabilizer in preparation for fitting the pushrod.

Since the pushrod needs to be fabricated and primed, I took a diversion next to install the control column.  This meant attaching the pivot brackets to the spar, then building the control column on top of them.  This task is complicated by all the various washers to be installed, and I had to fiddle with a few different combinations in order to get it to move smoothly.  After a final test fit and adjustment (these were initially fit during assembly of the center section bulkhead), I greased up the brass bushings and bolted the sticks in place.  I should be able to install the grips and wiring without removing them (crimp the pins, slide the wires down, then insert the pins in the connector), but I’m leaving the cotter pins out for now just in case….it’s s tight space and I’d rather only fiddle with cotter pins in there once.

I decided to go ahead and proceed with the rigging of the tail surfaces, in preparation for wiring the tailcone before riveting the aft skins.  Tonight I pulled out the horizontal stabilizer and elevators and got to work.  First, the bolt holes needed to be drilled for the center pivot bearing on the elevators…I didn’t do this when I first fit the elevators to the stabilizer, because a 1/4″ spacer is needed to serve as a drill bushing, and I didn’t have any.  Now, I have lots of scrap pieces of 1/4″ tubing–which actually is a bit too large to fit the hole in the bearing, I turned it down by chucking it up in the drill press and using sandpaper.  A #14 drill fits nicely in the inner diameter, so I used that to drill the bolt holes, then enlarged for the 1/4″ bolt.  Next, the control horns get drilled for the attachment of the pushrod, using the plan dimensions on the aft-most horn, then match-drilling the other through a block of wood to keep the hole perpendicular.  All of this required several on-off cycles of at least one elevator, so I was glad to still have my bent nail temporary bolt gizmos I made when did the initial fitting 3 years ago.

With the holes set for the elevators, off they come in order to mount the horizontal stab to the fuselage.  I put the stab in place and clamped it, then checked it for square by running a steel tape forward to a consistent point (I used the vertical of the spar carrythrough; my tape wasn’t long enough to reach the firewall as suggested in the manual).  I also checked left-right alignment to be sure it was on the centerline.  Both measurements were very close (within less than 1/16″) on the initial “eyeballed” fit, so a little tweak and it was good to go.  I clamped it to the aft deck and marked guide lines on the forward attach brackets and drilled them one hole at a time, moving clamps as required, first to #30, then to 3/16″ for the bolt.   (Finally, we’ve put the last holes in these brackets, the very first parts which are made at the beginning of the build…it’s interesting to ponder how that first encounter with “fabricate” seemed scary–I re-made those brackets, as many do–and now, “fabricate” just means “oh, okay” and another trip to the bandsaw, sander, file, and scotchbrite wheel.)

Trimmed the elevator counterweights on the bandsaw, a job that I started a few years ago and set aside because my hacksaw just couldn’t deal with cutting the lead blocks.  Bandsaw made quick work of them, with an old file to deburr the edges.  Finally, I cut the spacers that go under the HS attach angles and left them to cool for finishing on the next session.  I also need an 11/32″ drill bit for setting the rear HS spar incidence (it’s used as a precision spacer)…the closest I have is 21/64″, so perhaps I’ll stop off at a hardware store and pick one up.

Lots of little tasks to keep going on today…

Riveted the canopy decks in place!  This may come back to bite me later, but the instructions have this done long ago, and reaching over the fuselage witht he clecoes stabbing me in the gut was getting old.  Bucking these was actually quite easy; the tungsten bucking bar fits in the gap for all but the 4 rivets just aft of the spar upright, and for those, I just inserted the bar into the “channel” farther aft, positioned it horizontally (completely inside the channel), then slid it forward and held it up with my fingertips through the gap.  Method of assembly: completely remove the canopy deck and gusset, set all the rivets on the forward side of the bulkhead that hold the thick angle on the back, then install the gusset and rivet the 4 rivets on the top.  Finally, put the canopy deck back on and set all the rivets along the longeron.

Turned threads off of fuel vent fittings by chucking them up in the drill press; made the angle cut, and deburred.  Still need to find screen and attach it before these can be installed for good.  Installed fuel vent lines from vent fitting, to stub through fuselage side to tank.  Installed rubber grommets through side skin.  I spent quite awhile bending the first one to fit right, then the other side was very easy, just duplicate it in mirror image on the bench, and it dropped right in with only minor tweaking.

Installed rudder cables in the fuselage, and adel clamps at aft end.  (Need to torque and mark those screws.)  The string I had run earlier in the baggage area worked perfectly.  Installed the swivel fittings into the static ports and ran the static line between them, including the tee.  Ran static tubing forward, leaving a coil stored along the side of the fuselage with plenty of length to connect to instruments later.

Installed the flap actuator center bearing block nutplates, followed by the flap actuator, motor, and side covers.  Removed the side covers and set aside for later.  Need to order the Ray Allen POS-12 flap position sensor, which will mount somewhere in this area.

Installed Andair fuel valve to selector plate.  Used AN3 bolts for now, later I will probably replace this with different #10 hardware, some sort of more attractive screw.  Need to order more K1100-3 nutplates, since I stole from the supplied stock to mount the fuel selector.  Removed the elbow fittings from the selector, lubed the o-rings with EZ Turn, reinstalled, and staked the screws.  Like everyone else says, this valve is a work of art, and it’s hard to resist playing with the knob…no wonder it comes with a big red tag attached warning against “excessive dry operation.”

Cut down height of the boost pump “doghouse” cover by 1 1/4 inches, since the Andair pump is not as tall as the stock (AFP) pump and all the tubing/accessories that go with it, and more open cabin space is better.  I could probably have cut another 1/2″ off of it, even.  (By this point, it was getting late and I was working without stopping for many pictures.)  I used the opposite cover to mark a cut line 1 1/4″ down from the top of each, then cut and deburred, then used the cut off piece to re-drill the hole pattern in the top of the shortened side.  This seemed easier than cutting from the bottom and re-bending the flange as I’ve seen others do.

Began work on fuel pump installation, looking at how it will all fit together, and printed off the installation diagrams from Andair’s site for reference.

Finished the gear mount install by drilling the right side skins and bolting in place.  The right side weldment had a gap between it and the fuselage side (not uncommon, or so I’ve read), so I fabricated a shim out of some scrap stock, to fill the gap and prevent the side skins from bowing in under the torque of the bolt.  As a result, I upsized the bolts and added a thin washer, to get proper thread engagement.  Drilled and countersunk the forward holes, and installed those screws as well.

Next, I re-installed the brackets that hold the cover plates ahead of the main spar; the bottom screw is tricky to get in, as the screwdriver can’t get a straight shot due to the tube of the gear tower being in the way.  I tried a number of types of screwdrivers, including a right-angle gizmo, but a thin-shaft regular driver ended up working the best, even though it was cocked at an angle.  The clockwise side of the head got a bit boogered, I believe, so these screws will be one-time use: if they ever need to come out they will be replaced.  I also sanded a curve into the bottom of these brackets, to provide additional clearance to the gear leg tube which is very nearby, and was barely rubbing on the right side.  Test-fit the forward covers and filed the slots at the bottom slightly, to provide better clearance from the floor stiffeners.

Looking around for other odd tasks, I decided to put in the gusset plates that reinforce the seatback brace-main longeron joint, and drill those holes to final size for rivets.  Five holes per side, not difficult; the forward two on each side are countersunk.  Those plates are now clecoed in place, and I believe the canopy decks can be riveted at any time.

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.