Joshua’s RV-9A Project

Worked against the weather today to get the wing skins primed.  While the spray gear was set up, the baggage wall pieces were primed and painted, as well.  Thinning the Rustoleum paint has been hit-and-miss, and today’s batch was a miss…I think it was thinned out too far, and the panels ended up with very heavy coats to get the coverage needed without pinholes…they have a different look than the rest of the interior; for now, we’ll let it go, since there are other inconsistencies, and these panels can easily be pulled out, stripped, and repainted later if it becomes bothersome.

Also finished wiring the internal parts of the wings, trimming the wires to length and crimping on the connectors for the landing lights and the D-sub for the autopilot servo, and terminating the leads to the pitot heat control board.  I later realized that I have not yet run cable for the OAT sensors which will be installed in the right wing to feed the EFIS boxes.  I also epoxied some zip-tie bases to the underside of the seatback bulkhead for holding the headset jack wires, and installed the baggage light strip under there as well, using it’s built-in adhesive strip.

Neighbor Jeff stopped by to check on the progress; it’s been awhile since he’s seen the project.  People who see it now say it looks like an airplane.

A collection of things happening in the shop today.  First thing up, finish the canopy sealing.  The excess Sikaflex was rubbed off the exterior of the top skin and the inside of the rear window and canopy (from gluing the spacer gaps), followed by removal of the rear window spacers and insertion of sealant into those gaps.  Smoothed those over with tongue depressors and all looks good.  Some canopy work remains, of course, but the plexi is in place (which was the big summer goal).

Before the gear can be put on the fuselage, the wings need to be fit, which was skipped earlier in order to get the canopy done in the warmth of summer.  In order to do that , the wings will need to be finished (bottom skins riveted on, which means that they must be wired and plumbed).  Out came bottom wing skins, which needed edge deburring and a few dimples made.  After those were done, the skins were etched for priming along with the rear baggage wall; unfortunately it was too windy to prime until after dark, so that’ll have to wait for another day.

Cleaned up the inside of the wings, which had naturally collected a layer of shop dust and spiderwebs, and set about running the various wires and tubes for the in-wing systems (pitot heat, lights, strobes, AOA, and autopilot).  Everything except the pitot tube was run inside the corrugated conduit which was installed during the wing build.  A hole was drilled in the conduit near the aileron bellcranks, to permit wires to emerge for autopilot and pitot heat; once these wires are in position, some RTV can be used there to prevent any chafing on the conduit edge.  The control module for the heated pitot was installed on the rib near the bellcrank inspection hole, which should allow access to hook up the pitot wires later on.  The pitot tube was secured underneath the aileron bellcrank with an adel clamp to prevent interference or chafing.  All the wiring and tube will terminate at the wing root in connectors, to allow the wings and fuselage to be fully wired in the shop, and easily joined at the airport later on.

An unexpected warm weekend provided the perfect opportunity to prime the parts I had ready — essentially, the firewall and center section components, plus the aileron pushrods left from the wings.  The air was right for priming, warm and dry, and things moved quickly, though I did have to etch & dry the parts first.  After priming the parts, I let them dry for awhile, then sprayed the visible side of the firewall parts with Rustoleum Hammered from a rattle can.  We picked out the Dark Bronze color the other day at Menards, and I think it looks nice.  I was impressed with the pictures I saw from some other builders who used this paint, and though it may not be as durable as something like JetFlex (nor come in as many color options), I appreciate the fact that it can be easily touched up by buying another can from any hardware store.  Word on the street is that it reaches its max hardness after a week or two of curing.

While I had the primer out, I poured some into the aileron pushrods to coat the insides, and pop-riveted the ends on.  (Hint: don’t prime the mating surfaces of the pushrod and the end piece, rather, install them “wet,” as the thickness of two coats of primer makes an already tight fit an impossible one.)  Later in the evening, I squeezed the nutplates onto the center section pieces, and riveted the web stiffeners to the forward bulkhead, as well as dug up and installed the snap bushings.

Some odds and ends on the ailerons…put torque-seal on the bracket bolts, short pushrod ends, and put the ailerons back on the wings for safe-keeping.  Spent some time tidying the shop as well.  Still haven’t primed the long pushrod parts, as it’s been an insanely busy week.

Prepped the long aileron pushrods for primer, along with touching up spots on the wing needed to be spot-primed after assembly.  Greased and installed the aileron bellcranks; torqued the bracket-spar bolts, and the pivot bolts.  Also replaced the 4 bolts on each aileron that may have been overtorqued with fresh bolts & nuts.  The removed ones showed no signs of distress, but better to be sure than wondering when it comes to control surfaces.

Pulled in the wing conduits; a painless–if rather loud–process.

Spent some time monkeying with the internal workings of the wing.  Reamed the bellcrank bushings and turned them down to the proper length, then assembled both bellcranks.  Some of the bolts that came with the autopilot servo install kit are too short, so it looks like I will need to order a few longer bolts…add to the list.  I also need to look up what an appropriate grease is for the bellcrank bushings–the manual says “your favorite multipurpose grease.”  The stuff I have says it is rated to -20F.  Presumably, the possibility exists that the thing could be colder than that at altitude, so is it appropriate?  (Of course, my truck is lubed with the same stuff, and has worked fine in temps colder than -20F…)  I’m sure there’s a common aviation grease of some sort for this purpose, too.

Cut and drilled the pushrods, making them a bit longer than plans, as I’ve heard of some people wishing they had, when they had a hard time obtaining the required amount of thread engagement on the rod ends.  After dosing the insides with primer, I assembled the short steel pushrods (riveted per plans), but the longer aluminum ones still need to be primed & riveted.  Also had a bugger of a time locating the jam nuts for the rod ends (hint: look in the bag marked “spar bolts & misc”).

Temporarily put the bellcranks in the wings (I didn’t realize before that the bellcrank brackets had to come out, as the center bolt is too long to insert with the bellcrank in position.) and set the pushrod length using the straightedge aligned with the tooling holes and the bellcrank alignment tool.  I’ll have to get the protractor out and see if there is enough aileron travel the way it is, or if the spar pushrod holes need to be relieved to allow more clearance; the pushrod swings up/down and in/out as it moves through its travel.

Finished up the riveting of the left flap by attaching the bottom skin and squeezing the trailing edge.  After checking for twist (all looks good), hung the flap on the wing.  Flaps are done!

Fit the top skin and leading edge skins to the left flap, and riveted them in place.  Made a couple light smilies when I lost track of the gun during the vertical riveting.  Sigh…but no big deal.

Tonight’s session also saw the passing of the 500-hour mark on the build.  It doesn’t seem like that much time, but I have been working on the project for over two years (I started in earnest in May, 2007).  This means I’m somewhere between 1/4 and 1/3 of the way done, based on hours.  So, 4-6 more years?

A quick stop in the shop before heading off to work this morning finished up the remaining rivets on the right flap trailing edge.  A check for straightness & twist (all looks good), and the flap is attached to the wing — because it’s a good place to store it out of the way, and because moving parts are exciting!