Joshua's RV-9A Project

Indeed the sun is shining, the weather is record-setting unseasonable warmth (avg. high today of 51, we hit 79 here, and over 80 at the airport; at 23:30 local, it’s still 65).  Perfect fiberglassing weather, so that’s how I started the day.  Sanded some spots on the inside of the cowling, and laid up a couple plies of reinforcement when the nose-shaping operation had caused it to become a bit too thin.  Also laid up a new flange on the right bottom nose to replace the one that I cut off during fitting.  Added some micro to the leftover epoxy and filled some divots in the surface, along with putting a layer over the vertical hinge rivets on the aft edges.  Should have put one more batch before ending the night, but ran out of time.

Took another crack at re-bleeding the right brake to remove the air in the line (which causes “squishy pedal”), and got it this time.  Left & right pedal feel is equal now, both quite firm.

Decided that in the pursuit of progress, and given the generally-finished status of the avionics, wiring, and plumbing, it was time to nail on the forward top skin.  Sealed the forward edge with firewall sealant; I was able to set all but the longeron row + 4 rivets myself.  When Allison came home I conned her into shooting those remaining, while I laid upside down in the cabin to buck.  After that was done–as long as I was down there–I installed the top canopy hinge bolts, and the canopy pin mechanism.  During the solo riveting of the skin, I also secured the standby alternator relay & capacitor (which needed to move out of the way to allow bucking access).  Once the riveting was done from inside, I squeezed the rivets along the firewall, which also fasten the camloc strips.  With those in, I installed the three remaining camlocs.

It seemed natural to move next to the canopy, so I trimmed back the seal flange on the subpanel by 1/8″, to allow for an “edge gripper” type seal to be affixed.  We then installed the canopy on the fuselage, with much consternation around getting the hinges aligned with the pins (as the alignment marks I made earlier had been removed from the hinges during some cleanup).  Reaffixed the lift struts, and checked opening & closing operation, which worked fine.  The riveting of the top skin, as it seems to often do, changed the fit of things and created some “air scoops” on the pilot side, though the copilot side looks decent — both sides were alright before riveting.  So, I’ll have to decide whether to drill rivets & try to shim it up, or build that side up with (more) glasswork now, or later.  Since the canopy stops were removed to gain access for riveting the top skin, I reinstalled those, though they still need a little adjustment before locking them down.

Put in the pilot seat temporarily to sit in the plane and check fit & function of the lap belts, and operation of the canopy, brakes, and panel floodlights.

Finding no easy (read: cheap & fast) way to procure a 4-40 tap needed to clean micro out of the taillight attach nuts, I decided to have a go at it with a screw.  Which worked fine.  The empennage is officially ready to move the the airport.

Several list items in this weekend’s work session.

Having received the 1/4″ threaded drill I needed, drilled & deburred the crotch strap mounting holes.  Installed the crotch straps.  Drilled 1/4″ attach holes in the lap and shoulder belt attach points, and mounted those (RH lap belt temporary, as I ran out of the correct length AN4 bolts).

Final-installed the baffle screws with lockwashers.  Replaced temporary nuts with metal locknuts on baffle mounting brackets.  Fabricated and temporary-installed the baffle tension rods (need #6 metal locknuts), with nylon tube over the middle parts; they don’t contact anything as is, but should something shift, the nylon will prevent wear until the next inspection/oil change/etc.

Applied packing tape to the forward spinner bulkhead, laid a bead of flox on the inside of the spinner at the contact point, and clecoed it in place.  There was a moment of concern when the spinner didn’t want to release from the tape after curing for a few hours–I wanted to let the flox set up to hold proper shape before removing the spinner.  After pushing, prodding, tapping, and finally whacking it on an angle (it took quite a few good double-fisted whacks…that’s a strong piece of fiberglass…), one section popped loose and I was able to work it free.  Trimmed the squeezed-out flox off with a knife, to save weight and keep the spinner as balanced as possible, since this is part of the rotating mass.

With the first batch of fiberglass parts done, today saw the attachment of all the empennage tips to their respective stabilizers and control surfaces.  The emp fairing was set aside for the day the tail is installed at the airport, and the spray booth collapsed until the next round.  The only remaining item for the emp is that the taillight screw holes on the rudder need to be tapped to remove some excess micro that got in them.  After that, the emp parts will make their way to the airport at some point, to wait with the wings for the Big Move of the fuselage.

While working on the left elevator, also final-installed the trim pushrod and cotter pins.

The plastic covering on the canopy was the original as shipped in the finish kit, and had become quite tattered, along with being covered in dust and overspray of all sorts — I removed it, and will cover the canopy with layers of saran wrap to keep it pretty in the interim.  Today, cleaned, prepped, and attached the canopy side skirt pieces to the canopy frame.  Currently, they’re clecoed in place to let the bead of Sika cure, then I’ll add the rivets.  Also fabricated the exterior canopy lift handle (pilot’s side only, thanks) and drilled to the frame.  The canopy is very static-y when cleaning with a microfiber cloth, which means it didn’t stay clean for long, but every dust particle in the shop was attracted to it.

Re-bled the right brakes again, but still have a soft right brake pedal compared to the left.  I see no leaks, even under pressure, where air might be entering, so I can only blame the bleeder tank somehow.  Sort of disheartening, as the original system fill was rock-solid on both sides…too easy.  But the leaks at the pedals had to be fixed.  I wonder if draining the whole right side and refilling would provide better results.  I also wonder about the design of the bleeder valve, and whether air can’t find a path to enter there.

Decided to look at the installation of the crotch straps.  Pulled the seat pans and found that it would work well to simply drill a new hole in the crotch strap bracket, up from the giant factory hole.  I marked them in situ, and drilled both to 1/4″.  The geometry of this area requires an angle drill, but my largest bit is 5/16, so I will need to procure a 1/4″ threaded bit to complete the installation.

While messing around in the fuse with seatbelts, I happened to notice that four bolts were never put in the center section — whoops!  These are the bolts that go through the inboard tubing support brackets, just outside the fuel selector, top & bottom on both sides.  Obviously, I installed those bolts.

Two sessions today.  In the afternoon, sanded the K36 smooth — that stuff sands very easy — and sprayed a topcoat of DPLF epoxy primer, per the advice of folks at VAF, who say it is more resistant to oil, etc.

In the evening, came back to respray one elevator tip, whose finish was marred when the plastic sheet that makes up the paint booth perimeter fell on it while drying.  Argh, and it doesn’t look quite as good as the other, but good enough to last until the plane is painted for real…just trying to make sure the glass is protected and looks decent here.

Also tightened one more leaking NPT elbow on the passenger’s left brake, and re-bled the left brake system.  Replaced the broken right brake bleeder screw, and re-bled that side, but there was a continual stream of tiny bubbles in the fluid and the right brake is definitely softer than the left.  I think pumping up the bleeder tank put bubbles in the fluid when the level in the tank got low, so I filled it back up and pumped it up.  I’ll leave it set overnight to allow the bubbles to settle out, and re-bleed again tomorrow; hopefully that’ll fix it.

Mixed a dollop of Superfil and worked it into the few remaining pinholes before work.

Response to my question on VAF about topcoating the K36 (or not) until paint leans in the direction of spraying a final coat of DPLF, which will provide more protection from oil, etc.  It’s also a nicer color…

Wiped down all the fiberglass parts, and sprayed on a few coats of K36.  A few pinholes remain on the rudder top and empennage fairing; the rest are fine.  I need to figure out whether the K36 is acceptable to leave as the final finish, or if it needs another coat of something on top, to tide over until finish paint, which may not come for a good long while.

Scraped and sanded the filler which was applied in the previous session.  Shaped the rudder top TE to match the rudder skin.  Ready for more spraying when I find the time.

Mixed up some Super-Fil and worked it into the remaining pinholes on all the fiberglass parts that were sprayed yesterday.  Next will be sand the filler & spray another coat.

Pulled the top skin off and moved a couple pins on the ADS-B connector, since newer versions of the box have a slightly different pinout.

With the top skin off, found that a few of the elbow fittings on the brake cylinders were leaking fluid.  Removed the hoses and turned them in one more rotation, which, at least initially, seems to have cleared up the slight leaks.  Re-bled the brake system with fluid, and in the process managed to snap the nipple off one of the bleeder screws.  Dangit — at least it was only the nipple, so the brake system is closed, and I just need to order another bleeder screw.

Reconnected the oil temp sensor wire, which had been removed in a previous session to install an oil line.

Hooked up the new serial converter and it works; checked communication with the Pmags, and verified the configuration in the APRS tracker.

Finally, a work session with something more than sanding.  Worked a bunch of list items over a full day in the shop:

Brushed epoxy on the front of the top rudder tip, filling the pinholes in the micro which was sanded yesterday.  Added a blob of micro to the trailing edge, where the glass tip ended short of the metal portion.  I’ll refit this to the rudder tomorrow and sand the tip TE to match the rudder.

Set up a plastic-sheet spray booth, cleaned the HVLP gun,  and sprayed PPG DPLF epoxy primer on the canopy fairing, HS and VS tips, elevator tips, rudder bottom, and empennage fairing.  After that, it was time to air out the shop and bring it up to temperature again, as the epoxy primer and subsequent gun cleaning step kick off a lot of fumes.  I found only two pinholes in the canopy fairing, both over screw heads.  The emp fairing has a goodly number still (as I expected), and the tips have a few.  I’ll let the primer cure overnight, then fill the holes and sand level before laying down the K36 which is the next step in finishing.  That puts the second coat on schedule for Monday or Tuesday, though it looks like I may have to work on Tue night.  The recoat window is one week.

On to the cowling, I cleaned up the cut line on the rear of the inlet duct, then fabricated a piece of airseal and a metal backing strip, fitting them around the bottom of the duct.  This will mate up with the top piece, which is installed on the airbox, to seal the gap between duct and airbox.  A test fit, after tweaking the alignment of the airbox, showed it worked well.

Next, I countersunk all the rivet holes for the cowling hinges, and drilled some “ooze holes” in the hinge to give epoxy something extra to bond to.  Sanded the cowling and the hinges with a rough grit, and laid a bead of epoxy/flox along the hinge lines.  Clecoed the hinges on, then riveted them down, and cleaned up the flox that squeezed out all around.  Ran hinge pins through the hinges to make sure none of the eyes were epoxied shut.  Also floxed/riveted the oil door hinge to the cowl and door.

Put rivets in the remaining 5 holes under the left side canopy deck, originally left open to attach clips to hold the static line.  One hole was behind the center section cover, and inaccessible for bucking, so I used a Cherry rivet instead.

Torqued the nuts on the control cables at the quadrant, and the stopnuts on the control horns attaching the cables to the quadrant levers.  Verified that cotter pins were installed on the horns (they were).