Joshua's RV-9A Project

More work on fitting the spinner; finished the blade cutouts to an even 3/32″ width from the blade.  Set up a ladder to hold a fine-point sharpie while rotating the prop & spinner to ensure that the spinner was centered, then marked a line around the circumference at the rear bulkhead.  Using tape and a rivet fan, spaced 5 holes between each prop blade and drilled  #40.  These will later be enlarged to final size.  Clecoed the spinner in place and checked centering again, before removing and installing the forward spinner bulkhead.  This also requires trimming to clear the blades, and final-sizing the bolt holes to the required 7/16.”  The initial fitting of the spinner is done; the next step will be to add a bead of flox around the inside at the station of the forward bulkhead, to take up any remaining gap and minimize screw stress & vibration.

Cut the nosegear log slot 3″ longer in the lower cowl, to make it possible to clear the 3-blade prop.  I may extend it another inch still.

Sanded down the micro that I’d applied to the voids in the lower cowl nose, and marked lines on the top cowl where I’ll lay up some glass to close the inboard ends of the inlet ramps, to prevent cooling air from being dumped to the lower cowl without doing any cooling work.

No work for the next couple nights due to other commitments…

Finished the canopy skirts by stripping off the excess Sikaflex that oozed out of the joint and riveting the skirts in place.  All rivets were easily squeezed except five, which were bucked.  One of the nice things about Sikaflex versus something like Proseal is that, while it sticks with vigor to any properly primed surface, it doesn’t stick to things not coated with Sika primer; so it’s easy to not worry about the ooze-out, and once it has cured, just scrape or rub it off.  Cleaned all the dust off the canopy frame & underside.

Pulled out the prop and various related pieces — spinner, bulkheads, spacer, crush plate — and set to work making the blade cutouts in the spinner.  Measuring, making cardboard templates, and cutting, then shaping with a file, followed by lots of iterative fitting and filing, was the order of the day.  Got it to the point where it fits, though the cutouts will need to be cleaned up for a consistent gap width.

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.