Joshua's RV-9A Project

Countersunk & installed the lower HS fairing strips.

Installed an alternate static placard on the panel.

Re-fit the cowling and set the depth of the bottom cowl camlocs.

Fussed with the cowling, bulkhead, and spinner a bit, and came away not feeling so good.  The spacers I used when fitting the cowl must have been off by just a touch, because it now appears the cowl is shifted off to the left by a small amount.  The result of this is that the desired 1/4″ gap behind the spinner measures 1/4″ at the left side, but only 1/8″ on the right.  If the cowl hadn’t already been fit and drilled, hinges cut, etc, this wouldn’t be that big of a deal, just slide the right side aft.  As it is, I can see two options: 1) remove all the hinges, camlocs & such, fill the drilled holes, and refit the cowling, or 2) install the top skin, camloc strips, and camlocs (because I already drilled the camloc receptacle holes to full size, I can’t just cleco the cowl to the strips any more), attach the cowls in position, and rework the front of the cowling to provide the desired gaps.  The cowling might also be sitting a bit high, given the common recommendation to set it low to allow for engine sag.

All in all — Ugh.  I wasn’t looking forward to the fiberglassing to begin with, and this further dampens my desire to get started.

EDIT: After some reading, apparently this is not uncommon, and an accepted way to deal with it is to add layers of glass to the aft side of the cowl spinner area, and sand back until the gap is even all around.  Spots where the gap is too large can be built up with filler, and the nose reshaped as necessary.

Didn’t get part of Friday off from work as I’d hoped, but today I proceeded with the weekend plan of highlighting a bunch of items on the punch list, and knocking them off…

Mixed up a batch of firewall sealant (don’t smell that stuff…wow) and sealed the perimeter of the firewall sides and bottom, and a fillet in the lower corners.  The top curve will get done later when the top skin is put on.  Let that tack up, then clecoed & riveted the sides and bottom, along with the shims, hinges, and camloc strips.  By moving the exhaust stacks and using a variety of yokes, I was able to easily squeeze every rivet but the centerline bottom rivet, which was unsqueezable with any yoke from any angle.  That hole now sports a pulled rivet.  Once the camloc strips were on, the camloc receptacles were added.  Done.

With the lower edge of the firewall complete, I added the metal portion of the fuel pump vent line.  Done.

The metal fairing strips that run underneath the HS were next; drilled and tapped the appropriate holes in the aft longerons, drilled the strips, and test fit.  To see how the fit was, I added the HS back on for a moment, and marked the trims that needed to be made.  After several iterations, I had the 1/32 to 1/16″ gap called for in the plans, so the strips were primed.  Still need to countersink the strips, but Almost Done.

Removed the canopy strut attach blocks and primed/painted them.  While they were drying, I removed the blue tape that has been covering the canopy decks; underneath, I found (as I suspected) that some of the adhesive had become gummy, so that’ll have to be washed up.  Later, reinstalled the strut pivots, and reinstalled the assembly to the canopy decks.  Done.

Big job of the night: redo the intake studs in the engine sump so the nuts have enough threads protruding.  This required moving the exhaust stacks (again) and partial disassembly of the entire fuel servo/control cable works — not an easy task due to the limited room to swing a wrench; several of the bolts can only be turned one flat (1/6 turn) at a time.  Eventually, though, it was off, the studs removed, holes cleaned, and reinstalled studs to the correct depth.  Not much was really needed, only 1/8″ or so on each one.  Some of them ended up being a little longer than necessary, but there’s plenty of thread and the nuts are not bottomed, so all is well.  You don’t want to bottom the stud out in the blind hole, as it will stress the threads and can cause them to fracture.  I used a torque wrench to verify that the driving torque requirement was met, and installed with red loctite per the AFP manual.  Much reassembly later, we’re back in business, and the nagging “that’s not right yet” of those studs is gone.  Verified stop-to-stop movement of throttle and mixture.  Done.

Enlarged the drain holes on the fuselage to #19 based on talk that the #30 hole isn’t big enough, and (especially if any gunk is present) the surface tension of water will prevent it from draining.  Also added a drain hole at the lowest point of the fuselage (which is under the seats, and not at a bulkhead), and one under the fuel pump area.

Placarded the alternate static valve installed the other day, and remade the fuel purge and center cabin heat placards with white on black, which looks nicer on the black panel.  Also made black on clear labels for the extra PTT buttons on the fwd canopy decks, and for the pilot’s stick functions (PTT, Trim Up/Dn, and AP CWS)…I expect those will fall off over time and use, but my understanding is that it’s better to have everything labelled to the point of excess at inspection time.

Allison joined me in the shop for a bit to finish removing the tape gunk from the empennage fiberglassing adventure.  While she worked on that, I sanded the micro and shaped the edges of the emp fairing.  After fitting it back onto the plane, I’m pretty happy with the fit.  Now, I’m going to use this (and the emp tips) as a learning canvas for fiberglass finishing.  I have a box of PPG stuff here that I’m planning to use, which I chose because it seemed to be the most well-documented on the forums and build logs.

I also drilled the HS tips to #30, dimpled the skin, and countersunk the fiberglass.  These are ready for finishing, then attaching.  The goal with the fiberglass stuff is to get it to an acceptable level of finish and wearing a protective coating.  If it needs to be dealt with further, I can revisit it before paint (or let the pros make it shine as part of the pain process).

With the fiberglass dust (ack) cleaned off the workbench, I pulled the clecoes from the baffle airseal strips and installed the large-head pop rivets that hold it in place.

Finally, I installed the latest version of the EFIS software from AFS.  The problem where the screen blinks durin initialization when displaying the VP-X status page has not been fixed.  I pulled the config files to load into the computer and update some things.  (Hint: Linux works better than Windows for editing these files, as the line breaks display correctly…no surprise, since the AFS box runs Linux internally…)

I’ve also been working on the paperwork side, having built an InDesign project and templates for the POH, and compiling the “best of” from several existing POH’s that others have shared on their websites.  There’s lots of specific information to research and fill in, and plenty of stuff yet to write.  Being a layout nerd and a perfectionist, it’s possible to pour hours into this part, too.

Decided to apply the N-number decals tonight.  These are intended to be pseudo-temporary markings, until she gets painted someday, but they’re permanent for now.

Removed the airseal from the baffles, cleaned them, then ran a bead of red RTV along the baffles, and clecoed the airseal back in place.  I’ll let this cure overnight and install the baffle rivets tomorrow.  Also fitted the airseal to the top of the FAB.

And made up some pieces of airseal that will cover the spark plug access holes for the rear cylinders.

Received the prop spacer, crush plate, and bolt kit, and test-fit that to the engine.  Deburred the rear spinner bulkhead and test-fit that as well, along with the entire cowling, to see how close I came out on the cowling/spinner fit with my PVC spacers — looks like it will work.

Now that the emp fairing epoxy/micro sludge has finally set up hard, I went to remove the packing tape used to prevent the epoxy from adhering to the aluminum, and found that the plastic layer of the tape peeled off, leaving 90% of the adhesive behind, stuck to the plane.  Ugh.  Acetone doesn’t do anything besides make it gummy and smear it all over, so I’ll have to pick up some other solvents from the store and see what will remove it.  It doesn’t scrape well, but mechanical rubbing (with a finger) removes it slowly in little balls.  Clearly, some better tape is in order for future layups.

Trying to get the plane to the point where the tail feathers can be removed and stored, to allow more garage parking.

Fit the stock empennage fairing as best I could, which is essentially a ton of on-mark-off-sand-repeat, until it gets close.  Then I marked some final trim lines and sanded it back to there. Taped in place and carefully drilled #40 through the fairing into the open holes in the metal.

Next, to fill the little gaps that remain…  Taped up the metal surfaces and waxed them, and mixed up a batch of epoxy with micro and cabosil, slathered it on the inside of the fairing edges, and clecoed the fairing in place.  The idea is that the micro will fill the gap; once it’s cured, the fairing can be removed and the edges sanded pretty, then the rest of the finishing process can go on.

(Update: 55* in the shop is clearly not enough for efficient fiberglassing; the fairing took 4 days to set up completely, and that’s after pulling it off and bringing it in the house to sit.)

Also trimmed the layup on the cowling intake snout, and shaped it to be even with the intake.

Trimmed the excess from the aft end of the inlet duct, then chipped away the foam and the micro that held it in.  Sanded the inside down, and test-fit it back to the plane to see how it turned out — quite well, actually; the duct lines right up with the airbox.  Eventually, I’ll trim 1/2″ or so off the front of the airbox and attach airseal fabric.  Laid up one ply of 3″ glass tape around the duct on the inside of the cowl to add strength and thickness.  Once that cures, I’ll sand down the excess fabric sticking out the front and shape the nose of the inlet.

While I had the bottom cowl on, fit the top cowl to check fit of the airseal fabric; looking good so far.  I curved it over and added some paperclips to try and train the fabric to bend in the correct direction.  Tied up the engine heater wires behind the sump, torqued the baffle screw behind the dipstick tube, then installed & safetied the dipstick tube.  Plugged in the engine heater and verified it was still functional.

Finally made it to the airport yesterday to go flying with my CFI and get current again.  It came back better than I expected, and he was satisfied enough to sign off on my flight review, which was due at the end of the month.  That stamp says I’m basically safe…now the task is to fly enough to get proficient and fly accurately, then I’ll set up some transition training with one of the CFI’s who does RV-specific training, in preparation for getting this thing off the ground someday.

Milestone: crossed 1500 hours logged on the project tonight.

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.

Crimped a ring terminal to the buss end of the SD-8 power wire, and secured it to the VP-X stud with the main buss feed.  Verified proper operation of the SD-8 relay.  Loosened the capacitor and relay to allow bucking bar access above them for riveting the top skin.

Back to baffles for a bit; set up a row of paperclips around the sealing edge and put the cowling on; this pushes the paperclips down and reveals the spacing between the baffle edge and the cowl.  Once the cowl is removed, I marked a line 1/2″ down from the top of the paperclips, and used that as a guide to trim the baffles, aiming for the specified 3/8-1/2″ gap.  Rough cut with snips, cleaned up with files, finished with scotchbrite in the die grinder.  Refitting of the cowl revealed a couple small areas that may need a wee bit more trimming or a change in contour, but that’s easy enough to deal with.  Should be ready to cut airseal fabric soon.

I’ve slowly been adding ignition wires as time goes by, so I decided to put the rest of them in, and start work on tying them up.  I sorted out the various lengths and determined which is intended to go where, then started working from the spark plugs aft.  Swapped around some baffle/valve cover screws to get adel clamps installed on the lower screw of each valve cover, to hold the bottom plug wires.  I’m making spacers to secure adjacent wires with zipties and short pieces of silicone tube left over from the manifold pressure plumbing, similar to what’s shown in the Pmag docs.

Also started work on the heater SCAT tubing, and got most of that routing sorted out and tube secured.