Joshua's RV-9A Project

Over the past two nights, spray-painted both sides of the steel links that connect the rudder pedals to the cables.

Sprayed primer on the forward top skin, and left to dry overnight.  Located the steel strip from which the rudder pedal links are to be cut; marked and cut those, drilled the holes, and rounded the ends on the bench grinder.  Sanded them down, and sprayed a coat of primer to keep them from re-rusting.  Tomorrow I’ll spray a topcoat on them, and then they will be installed prior to riveting the top skin, to take advantage of easier access.

Took some high-resolution photos of the area forward of the subpanel, which may come in handy later on when I need to recall how something was done under there, or visualize it from a different angle prior to stuffing myself under the panel to work on it.  Then, started prep on the forward top skin, which’ll soon be riveted in place over that area.  Deburred, dimpled, and scuffed the skin.  Hopefully we’ll have a warm calm evening this week to shoot the white primer on it–I’ve used white on everything in that upper area, with the hope that it will make working up there more pleasant/visible later.

I need to pick up some more syringes from the farm store to use for placing the firewall sealant before riveting.

Took another look at the fit of the empennage fairing; I’d like to get that done before the weather turns too cold, so that I can pull the tail feathers, move them to the hangar, and have room for cars in the garage during winter.

A very fiberglassy day, once again.  Also did a bunch of (more) reading on what primers and other coatings are required/recommended for finishing the glass parts.  I’ve identified the list that I would need if I were doing prep for parts that would be painted now/soon (PPG DPLF, followed by K36 or K38) — the part I need to sort out still is whether that is an acceptable stopping place for a plane that likely will not be painted for several years, or if some other coating/sealer/etc needs to be put on top.  I found that the K36 can be mixed either as a primer/surfacer, or as a sealer, where a base or clear component is added; perhaps that’s a good final step.

So, today’s work…sanded the epoxy coat on the HS/VS tips — that stuff is hard.  Which is as intended, really…but I was still surprised at the amount of work it took to sand.  These are now ready for the priming/finishing steps.  I need to get the rest of the empennage tips to this stage as well, then I’ll have a go with whatever process I settle on.

The next big job was to create the union between the lower cowl and the airbox.  Firstly, the front snout of the airbox needed to be trimmed back sufficiently to give clearance for the cowl to drop down vertically, so it can be removed with the prop in place.  This took several on-off-trim-test cycles with the lower cowl; I put the top plate of the box on the servo and trimmed that to fit, then trimmed the fiberglass bowl once the last trim point had been established.  I cut a hole through the middle of the foam blocks attached yesterday with a hole saw, then used files to work it out to the necessary size and shape.  During this process, I discovered that the epoxy I used yesterday to glue the two pieces of foam together was too hard for the job; the rear foam piece cracked off when the hole saw hit the layer of hard epoxy.  So, I made some measurements and fit another piece of foam to the aft side, using contact cement and a screw in each corner because I’m impatient and didn’t want to wait for it to set up.  That worked out, and I was able to shape a nice transition to the airbox.

With the transition duct mold done, I had to do a layup to form the actual duct.  Wetting out the cloth (2 layers of the Rutan bid) was easy, putting it in place inside the duct, and getting it to stay there, was another story, but I emerged victorious, if a bit sticky.  To finish off the inside, I cut another piece of cloth, some lighter, tighter weave stuff I got, and laid that up as the final inside layer, which should leave it a bit easier to finish than the relatively coarse cloth.  I secured this all in position and left it to cure.  Later in the day, I trimmed the long excess and brushed a layer of epoxy on the inside, as the first step toward finishing.  Sanding inside that duct will be fun…  Tomorrow, assuming it’s set up enough, I’ll remove the foam and lay up another layer or two of cloth around the outside of the duct to securely fix it to the cowl.

Spent a bit of time cleaning up the shop, stuffing the trash pile in the corner into the garbage can and sweeping, before moving to the next task.

I decided to tackle cutting and fitting the airseal fabric on the engine baffles.  Started by making templates of all the baffle tops from cardboard, then cutting 3″ wide pieces of fabric matching those curves.  Laid out a rivet pattern on both side baffles, and drilled/deburred.  Taped the fabric in place and marked the holes, then drilled them in the fabric on the bench–the fabric is tough to drill, and didn’t drill well in place.  Even on the bench, it didn’t really drill, just poked a hole through.  Some have had luck here with leather punches, though I can get clecoes and rivets through the holes, so I don’t know how critical that would be.

The side baffles are in two pieces, to match the fore/aft split in the baffles.  I made nice curved pieces for the front segment, but they needed to be cut once in place in order for the fabric to bend over properly.  One cut overlaps itself, but the other opens up a gap, so I made a gap filler piece for each side, as well.  The aft segment, which came next, is also in two pieces, and the right side is captured between the baffle itself and the bracket which is bolted to the engine case.  Laying the top cowl on, it seems like these will work.  I need to see what’s needed for adhesive when affixing these — I bought some Pliobond earlier, but for these which are riveted, perhaps just red RTV is the thing to do.  I have not yet dealt with the front baffle, since it needs additional trimming and figuring out the interface to the top cowl.

Also need to sort out how the airseal fabric works at the front of the airbox; it appears that it’s riveted to the outside of the airbox, and seals as best it can around the outside of the cowling duct, not the inside.  I made the second piece of foam the right thickness so that the foam very nearly touches the opening of the FAB as currently trimmed, and I’ll trim the fiberglass of the duct to that point before removing the foam, so that obtaining the correct gap between cowl duct and FAB will be an easy task of measure and trim.

More work on the fiberglass stuff…

• Trimmed yesterday’s layup on the FAB; spread some flox/epoxy into the gap, and added another ply of glass on the inside.
• Scraped and sanded the epoxy runs off the HS/VS tips; the epoxy isn’t fully cured yet so will wait until later to sand, when it’s harder.
• Did a little cleanup on the empennage fairing, scraping off the unidentified brown goo splotches from the factory.
• Tacked the foam block into the cowling snout.

And a bit of non-fiberglass stuff for sanity…

• Torqued & sealed the fuel hoses at the flow transducer; FWF fuel system now complete.
• Torqued & sealed the oil cooler lines; oil system now complete.
• Deburred & dimpled the flanges of everything subpanel & forward…moving toward riveting the top skin.  Also had to remove the canopy pin mechanism, which will be fun to reinstall from under the panel while laying upside down…
• Removed the camloc strips, deburred and dimpled the attach holes.
• Cut a sheet of .020 and bent an angle into the edges, then fit it to the bottom of the fuel pump mounting plate.  Since this piece has a bunch of nutplates on the bottom of it, and many tubes & wires run beneath it, I decided that having a sheet in there would be a good idea to prevent any possible chafing (there is clearance between the plate and the bundles, but just in case, vibration and all that…).  This looks like it will do the job nicely.  It’s tacked to the mounting plate with a blob of Goop at each corner, and one in the center.

Doing some evening reading and working up a list for tomorrow, when I’ll again ignore all the other work that needs to be done to spend the day in the shop.

Long week of work at work, and haven’t really had/taken time to work on the plane.  Looks like flying this weekend will be a bust due to the schedule at the FBO.  Off to the shop tonight to make some way on a bit of fiberglass work; this gets annoying because you can only do so much before you have to put it down and let it sit until the epoxy is cured.

• Laid up 2 plies of glass at 45* to each other on the FAB split.  I’ll let this cure, then add more glass to the inside of the box.
• Brushed on a coat of epoxy over the shaped/sanded micro on the elevator & rudder tips.
• Sanded on the upper cowl inlet ramps until my arm wore out, smoothing the micro that was applied earlier.
• Added a small layup of a couple plies of fabric on the inside of the emp fairing, the top aft side where it is torn (came out of the box that way).
• Filed a bevel on the inside of the air intake snout, the first step of creating the duct that routes the air into the FAB.
• Cut the supplied foam block from the FAB kit in half and glued the two halves together, in prep for fitting it to the cowl snout and FAB.
• Went back to the shop later in the evening and put down another coat of epoxy on the elevator/rudder tips.

Started out by giving more attention to the HS/VS tips (the elevator/rudder tips don’t require so much work, and I’m glad for it).  Sanded the filler layer of micro I added yesterday, and got things looking relatively decent.  Spent some time reading on what the process is from here; it looks like there should be an epoxy sealcoat or three over the microed area, then a primer, and possibly another primer after that.  I’m reading much of what DanH has written over at VAF, and have found the specs for the PPG coatings used by many of the folks; have to see if there is a local supplier, or if it’ll be a mail-order operation.  DPLF is the basic primer, and K36 is the high-build primer/surfacer.  The finishing steps, as I understand them, are to brush or roll 3 layers of straight epoxy, then sand, shoot DPLF, sand/fill if necessary, then a light coat of DPLF and a coat or two of K36.  I don’t know if the K36 step is needed at this point, or if that’s something that’ll happen at paint prep time.  After sanding them up, I added a fillet of flox to the inside of each tip, to strengthen up the joint at the back.  Hopefully these will be done soon…

Next I tackled the pre-installation for the SD-8 backup alternator/dynamo.  I’ve installed the relay and capacitor, but haven’t bought the regulator or dynamo to save the $500 for the moment.  This is purely a backup device, so I don’t need it to get flying, but want to add it eventually.  I drew up a full-size paper mockup of the regulator so I could locate nutplates to secure it, and installed those.  Then, I installed all the wiring, and ran the lines which run to the regulator to a CPC connector mounted below where the regulator will go.  When I get the regulator, I’ll put a mating CPC on it, and it’ll be a simple matter of bolt in and plug in.  Also ran a loop of wire FWF and secured the excess length to the wire bundle along the upper engine mount tube, where it’ll stay until the installation of the dynamo.

Started on the installation of exhaust mounts.  Tightening down the bolts on the ball joints to the specified 2-threads caused them to become rather tight, so I may need one length longer bolts there — not sure how tight or loose it’s supposed to be, but the install guide does say that it’s important they be able to flex, and recommends lubricating them regularly.  Got the right side hangers fit, and the left side marked and cut, before quitting time.

And, stuck the biennial registration sticker on the ELT.

Sanded down the filler that was added to the empennage tips, checked fit, and put on another thin layer of micro to fill the voids opened up by the sanding.

Still working on getting the wings to the point of being ready to move to the airport.  Installed all the nutplates (52) for the wing root fairings, after making a poor man’s nutplate jig (insert a screw partway into the nutplate, then cut the head off) for both the two-leg and one-leg nutplates.  Had to dig a bit to come up with the one-leg dimpled nutplates for the 4 locations that require them.  Nothing difficult, just lots of repetitive little stuff.  There is one nutplate hole on each lower leading edge that’s impossible to dimple with the dimple dies because the tank support bracket is right behind it — I found that it worked to install the nutplate, then use a screw with a tinnerman washer to form the dimple.

Also deburred, dimpled, and primed the wing inspection plates, and poked at the empennage fairing a bit more, to think about the next steps in fitting it.

Trimmed and sanded the edges of the glass layups on the HS/VS tips, then mixed up a batch of micro and slathered it on the inside.  Once it’s cured, I’ll remove the foam rib and finish the inside layups.

Laid up another ply of glass on the back of the empennage tips.  Hopefully that will stiffen it up enough to remove the foam rib and add glass to the inside.  Left to sit and cure overnight…this glasswork looks like it’ll take awhile just because of all the waiting around.

Riveted in the rest of the wing inspection panel nutplates.  All that’s left on the wings for now is to drill, countersink, deburr, and rivet in 52 more nutplates for the root fairings.  Oy.  I’ve dealt well with all the nutplates on the project so far, but this job makes me wish I’d bought a nutplate jig.