Joshua's RV-9A Project

A bundle more of fiberglass work today, including my first real dive into mixing up epoxy with additives, and using it for more than sticking a ziptie base to something.  By the end of the day, I had used four small batches for various things, and had the discarded cups to prove it (I kept the excess in the cups and set them aside so I’ll be able to verify that the batch cured correctly, without any mixing errors/etc, and to observe how, and how quickly, the different mixtures set up):

First on the list was to take the necessary steps toward finishing up the empennage tips.  I used a 1/2″ wide steel rule as a spacer to mark a line on the HS/VS tips, that distance from the edge of the counterbalances.  Then, I drew a parallel line 1/4″ back, and cut/filed/sanded to that line, for an even 1/4″ gap.  I suppose this gap could be tighter, but a wider gap leaves less chance of fouling a control surface should something go awry or debris enter in…and, it could always be tightened back up with, you guessed it, more fiberglass work later.

With the gap and shape established, I re-fit the tips to the stabilizers, and formed ribs out of some styrofoam saved from the fuselage shipment; these ribs were inserted into the tips and will serve to hold the shape of the tip during the next steps.  I mixed up epoxy with some flox to a peanut-butter thickness, and formed a small fillet to the rib, to hold it in place.  Herein is the downside to fiberglassing (besides the mess): once it’s in place, it takes several hours to cure to a point where it’s workable.  So, on to other things while it does that.

Meanwhile, I wanted to get the “elephant ear” cooling ramps on the upper cowling, so I can continue trimming of the baffles.  I found a position where they fit well with the contour of the cowl, and drilled two #40 holes for keeper clecoes in the inlet flange, to hold the forward edge of the ramps while the epoxy set.  Mixed up another round of the flox paste, and stuck them on (after sanding to roughen them up, air-blowing the dust off, and a solvent wipe).  Again, sit to cure…on to other things.  Later, once it had set up a bit, I came back, pulled the clecoes, and slathered on an epoxy-micro-cabosil mix at each end of the ramps, to start in creating a smooth transition surface.  It’s trowelled on for now, then the micro mix (which supposedly sands really easy) will be sanded down to smooth it out.  It’ll probably require a second application, too.  But for now, good enough.  Left to cure overnight.

Back to the HS/VS tips; by now the flox fillet cured up well enough that they could be removed from the empennage and they retained their shape.  I cut some pieces of bid cloth and wet them out with straight epoxy in a plastic sandwich, and applied them to the aft side of the tips, covering the foam rib.   I set those aside to cure overnight; the idea is to remove the foam rib, then lay up additional plies of glass on the inside for stiffness.  I may need another ply of glass on the outside before the rib can be removed, I’m not sure — we’ll see how stiff it is tomorrow.  Once the inside plies of glass are added, the remaining void on the back will be filled with micro, and the whole operation sanded down to make a nice smooth tip closure, then primed.

In between waiting for epoxy to cure, I also: cut the slots in the fuselage side tank support brackets, primed them, and bolted them to the fuselage.  Drilled a drain hole in the rudder bottom.  Deburred the wingroot holes for the gap fairing screws.  Drilled and hole-deburred the wing inspection plates. Finished bending the ends on a cotter pin on the engine mount that I’d missed doing that for earlier.  Found the scribe line on the empennage fairing and rough trimmed to it — made the fairing fit much better, it actually looks usable now.  Drilled holes in the corners of the dataplate.

There’s a bunch of nutplates that need to go on the wings (root fairings and inspection plates), then they’re essentially ready to move to the airport — I could also do the tip light wiring before the move, too, but that’s not a big job (cut to length, add connectors, add local ground wire).

ELT batteries came in the mail this morning, so the first item on the list was installing them.  The lithium batteries are good for 10 years, according to the ELT manual, but the expiration date on the batteries is March 2020, so I’ll enter that as the replacement date.  With the batteries in and everything back together, I armed the ELT and pushed the button to initiate the self-test.  One beep came from the audio alert, which is supposed to indicate that the system has passed all its checks and is good to go.  Disarmed the unit.  Also, reached up into the tail and tightened down the nut on the ELT antenna.

Spent the rest of the day working on the empennage.  Lots of fitting, trimming, filing, and sanding of fiberglass tips.  The vibrating saw I bought for the canopy work also works very nicely on fiberglass, so I’m using that to do the rough trims, then following up with a flat file, a triangular file, a half-round file, and a 2′ 1×3 with sandpaper glued to it.  (Drywall corner bead adhesive works really well to stick sandpaper to a board.)  And, the heat gun to warm up a couple recalcitrant parts so they could be shaped.  Finished basic fitting of all the empennage tips, though there’s still plenty to do.  The VS tip needs to have some height added to it to match the rudder, and the left elevator tip has a dip molded into it that will probably need filler.  Plus, there’s the closeouts of the VS and HS tips with foam/fiberglass/micro/shaping them to match the control surfaces with acceptable gaps.

The rudder bottom was the most time-consuming, since it needed lots of trimming to fit around the rudder horn.  I initially trimmed to the scribe lines, and they were close, but not quite.  I have a bit much of a gap under one side rudder horn (oh well), and the other side needed to be sanded down at a taper quite a ways more before the centerline of the tip was in line with the trailing edge.  Once it was fit, I proceeded to fit the aft nav/strobe, using rivnuts to mount it.  Wired it up, adding the local ground called out in the new version of the recommended wiring diagram, and flipped the switch.  Worked well, though the nav light draws so little current that the VP-X’s no-current fault indicator kept tripping it offline, so I disabled that for the nav light circuit.  The strobe draws enough current that it keeps the strobe circuit from faulting; once the other 2 nav lights are connected, I can try re-enabling it on that circuit.

From the “I don’t really feel like going out to the shop but I need to do something to keep moving” file…

Removed the -14 adel clamps from the main vertical wiring trunk, and installed -15 clamps, which are large enough to contain the few wires that wouldn’t fit in the smaller ones that had been originally installed.

Terminated the boost pump power & ground into a 2-pin molex connector to mate with the one I had previously installed on the pump leads.  Test fit and tested that the pump powered up.

Wiped off the rest of the fiberglass tips for the empennage, and traced the initial trim lines with a black sharpie.

Installed the RJ-11 connectors on the ELT remote cable, and plugged it in on both ends.  The batteries I ordered shipped today, so when those arrive, a test will be possible to verify that it’s working correctly, then the ELT can be deemed fully installed.

Made up a couple 2″ test links for the rudder pedal-cable connection out of scrap alum, to test that length before committing to cutting the steel pieces.  Seems to be alright, one thing I noticed is that at full travel, the swaged end of the cable hits the first snap bushing behind the pedals.  Not sure what that’s about, or if it’s normal, but the thing setting that location is the length of cable from the rudder horn.

Having picked up some different adhesives last night for the glareshield covering, the first item on today’s agenda was the finished that job.  I had stupidly gotten ahead of myself and removed the inside plastic covering yesterday, in order to be able to work better down in the tight corners at the front.  So, I taped up a bunch of newspaper on the inside of the canopy, to mask the bubble against any overspray.  Feeling sufficiently masked, I sprayed some Super 77 on the glareshield, and a coating on the backing of the fabric, waited the appointed time, and stuck them together.  I did have some troubles with the fabric sticking to the newspaper in the corners, duh…I knew there was a reason I had planned to not put adhesive on the fabric.  Sigh.  In the end, though, it stuck down well, and laid nicely.  It appears that even with my newspaper mask, a couple areas of plexi got a light fogging of overspray, aargh.  I’ve read through the VAF threads about canopy oversprays & cleaning, and sent off for some supplies from Spruce.  This too shall pass, with some elbow grease.

With the fabric in place, I inserted the snap bushing and GPS wire…looking good.

Next task was soldering the ELT connector, so I climbed into the baggage compartment again with tools & supplies.  Easy enough, then I made the LED test tool specified in the manual, which lets you see if the GPS signal is being received by the ELT.  It was, so I buttoned that install up; if I can remember to bring my modular crimpers home from work tomorrow, I’ll be able to put a bow on the ELT installation and cross that off the list.  I also ordered the batteries for the remote units today, having failed to find them at 3 local stores that carry camera batteries.

I decided that for whatever reason it was time to set the lengths of the control system pushrods, so I moved things around enough to fit the empennage.  I also primed some spacers and things that needed priming, part related to the empennage attachment.  Bolted on the HS and mounted the elevators.  Decided to fit the HS tips, so I had to do a little bit of trimming, and cleaned up the stepped edge to a nice crisp line with files, before positioning and drilling.  A couple trips in and out of the tailcone had the pushrods adjusted to get full stop-to-stop deflection of the elevators, hitting the travel stops at the elevator end rather than the control column end.  I measured the travel of the elevators to verify it was within spec, and it was.

Since I had the elevators rigged up, I figured I would connect the trim servo and configure it in the VP-X and EFIS.  That was a simple proposition, but I found that the pins for the up/down trim commands into the VP-X needed to be reversed opposite of what’s indicated on the load planning document (ie, 18 down, 19 up).  Once the correct motor polarity was set, the buttons in the software caused the servo to move correctly (“move up” moved the tab down for nose up trim), but the stick switch was running opposite that.  I tested the pins to be sure that I hadn’t reversed them accidentally — I hadn’t, the one marked up was indeed grounded when the up trim switch was pushed.  Swapping the pins at the input of the VP-X allowed it to run as expected.  Not sure what’s going on here, and I’ll be sure to double-check this system later to be sure it’s functioning properly, that I didn’t just have a bad brain day and set it up backwards.  Once it was running right, I measured the travel of the tab to be in-spec, as well.

Finally, mounted the VS and rudder.  Connected the rudder cables to the rudder horn.  Looks like I’ll need the connecting links to be around 2″ long — now, where to find the steel bars that they’re made from…  The rest of the empennage tips will get fitted next, I think; a little fiberglassing practice to close them out, then those surfaces can come back off for storage until final assembly.

Received a couple supply orders this morning, from SteinAir and McMaster, so parts were on hand to complete a few tasks.

Installed the intake gaskets and bolted the fuel servo and spacer/bracket to the sump.  I bought some all-metal steel locknuts in 5/16-18, which is the thread on the long studs AeroSport sent to me.  I’ve installed the standard-height ones, but even with a thin washer, the threads are only flush with the bottom of the nut, rather than the usual 1-or-2-thread protrusion we want (though they do appear to be fully engaged; there’s just no excess).  I installed them for now, torqued and sealed, but will ask around to see if this is a real problem; if so, whether using shorter nuts (which I also bought) would be acceptable here, or if I’ll need to locate and install longer intake studs (ugh).  In other FWF news, torqued the engine mount bolts and installed cotter pins.

Installed the quick-connect fittings on EFIS 1, into which were installed the pitot and static tubes.  Blowing lightly in the pitot line at the wing root caused the airspeed to come alive, and capping the tube off cause it to hold steady, so the system within the fuselage appears to be tight.  Sucking lightly on a static port indicated a climb, so that’s good too, though that one isn’t guaranteed leak-free, as I wasn’t able to plug the opposite port and hold suction; that test will come later.

Moving toward finishing the ELT install, I drilled a hole in the aft top skin for the antenna, and fabricated a circular doubler to go inside, per the installation guide.  Routed a coax from the ELT to the antenna, secured and terminated.  Hint: a BNC connector doesn’t fit through the 1/2″ hole for the antenna, and if you install it with the coax pulled to the outside because it’s easier, you’ll have to cut it off and do it again, the hard way…don’t ask how I know.  Routed and secured most of the wiring around the ELT itself, though the wiring is not done yet.  Some fiddly soldering on a 4-pin DIN needs to be done to hook up the power and GPS signal (why they chose that awful connector, I don’t know…).  And, I need to terminate the RJ-11 ends, and of course my RJ crimper is in my toolbag at the office.

In the same area, installed a nutsert for the APRS box, and secured that along with it’s wiring.  Placed a couple ziptie bases along the wire run to the RS-232 service port and status indicator light and secured those wires, as well.  Still haven’t seen any pings from the APRS show up on the internet, though that’s not surprising as it’s been in the garage the entire time.  I might push it out someday and see if it’ll ping, but with the bottom-mounted antenna, I don’t really expect to see anything until she’s airborne.

And as long as I was working in the tailcone, I finished securing the wires that run along the floor, including the addition of a few ziptie bases.  Also removed the test-fit magnetometer mount, deburred and primed it so it can be riveted in place.  I see at least a couple more trips into the tailcone (mag/mount install, finish the ELT, install the elevator pushrod) in my future, but hopefully I’ll be done with that soon, at least for awhile.  Once you’ve got camp set up in there, it’s not so bad, but getting in and out is a bear…and even more fun when you get yourself inserted and then realize the tool you need is still on the bench.

In keeping with the tailcone theme, but on the outside, I installed the rudder cable fairings that were prepped yeterday.  The night’s last act was to install the nutplates on the elevator horn inspection holes, then prep & prime the cover plates.

Checked the FAA registry tonight and saw that my N number is now showing as assigned, with the proper details of my airplane.  So, it appears my registration has been received.  I’ll laugh if the state tax people call up in the middle of the current government shutdown to ask for their pound of flesh…

Trimmed the UHMW block for the top canopy latch, and drilled the holes which bolt it to the canopy frame.  Found a washer that fits the shaft of the latch, and drilled the shaft for a cotter pin, but discovered that the washer’s OD is too large to fit on it; it hits the canopy frame.  I’ll have to dig deeper in the bags, as I must have pulled the wrong washer.  I’m also planning to install the spring modification that others have done, which allows the latch to tuck up parallel to the canopy frame, eliminating the possibility of locking oneself out of the plane if the latch were to slip.

Installed plugs in the open ports of the pitot & static manifolds.  I installed these manifolds to allow for easy expansion in the future, to run lines to a second/third EFIS, autopilot, and whatever new gadget comes along that needs it.  I haven’t found the second long screw I bought to secure these, though…looking like a fresh one from Menard’s.

Installed the center bearing block for the rudder pedals.

Shaped the upper body of the Gretz pitot tube slightly as needed to fit into the pitot mast, put the nutplates on the mast, and installed it to the wing.  Then, installed the pitot tube to the mast after trimming the pressure line and wires as needed, and wired/plumbed it.  I decided to try using a straight quick-connect union to join the 1/4″ copper line from the pitot tube to the nylon tubing which runs through the wing, since they’re supposed to be OK for all types of tubing.  If it doesn’t work, there’s plenty of room and remaining length on the tubes to do it a different way.  With the pitot installed, I rolled the wing cart over to the fuselage and plugged the left wing in, to verify operation of the heater.  Cooling it off with a cupful of ice water caused the heater to kick on, and the indicators indicated appropriately.  Check.

Drilled attachment holes in the rudder cable fairings, then match-drilled them to the fuselage.  I went with one hole in each corner for a total of three; if this proves not enough, it’ll be easy to add two more holes halfway along the sides.  I plan to attach these with blind rivets; easy, and easy enough to remove with a drill if needed later.  Primed the inside surface of the fairings and left to dry.

When testing the pitot heater, I had all three of the annunciator lights lit up on the panel, and grabbed a couple photos.  I really like how these LED indicators worked out, even though they were a bit pricey.  They may end up being too bright at night, but with the way they’re wired, it would be simple to add a bright/dim switch, or even a dimmer pot.  And, they should be dark in the normal condition, so it may be a non-issue.  (The camera makes them look brighter than they actually are, too; the hotspots in the photo aren’t apparent to the naked eye.)  I’m still very happy with the panel design & layout; putting that together was, as expected, one of the highlights of the project.

Just a bit of time in the shop after working 9 hours during the day on other things…what vacation?  Riveted in the panel brace, reinstalled EFIS 1 and connected the AOA tubing, mounted the ELT bracket, and clipped some wireties from a previous session, along with the usual staring at the project to see what’s next.

Spent some time sanding, smoothing, and scuffing the panel, then shot it with primer.  An hour later, sprayed the flat black finish coat.  Brought it inside for the night to dry in the warm(er) house.

I often find myself bouncing around the project lately, where I may be working on three little jobs at once in different parts of the shop…waiting for paint to dry on a couple things, for instance, while drilling something and wiring something else.  So when I sit down at the end of the day to write these logs, it’s sometimes challenging to think back and remember everything I did that day.  Pictures help, but I’ve had a bad time remembering to take a photo of every little job, too.

Today’s work…

• Riveted the right cabin heat control bracket to the vent bracket, which was then riveted to the side skin.  Installed the control cable and secured it, which required some modification to the firewall passthru, as the cable was just slightly loose in the eyeball.  I used a flat file to shave just a bit off the flat side of each ball halve, which allowed it to get a firm grip on the cable and secure it in place.  Cut the casing and cable to length and assembled.  Installed the right side vent nozzle.

• Traced the spare round-gauge hole, and the autopilot head hole, onto scrap stock and cut it out to make filler panels for those cutouts, since they will not have instruments installed in the until phase two of the panel.
• Fabricated angles for mounting the radio stack to the panel.  Waiting to drill them to the panel until the radios are in hand, in case the width of the trays is a bit off of the width of the panel cutout.
• Cut a hole in the subpanel behind each EFIS screen to pass the wiring harnesses and pressure tubing.  Also put a hole in the lower right subpanel for the wiring feeds to the switches on that side of the panel, in addition to the hole that’s already made for running cable to the dimmer module.  I have a couple sizes of nice rubber grommets from McMaster, in addition to an assortment of snap bushings that I bought from Van’s awhile back; finding the right size for a particular hole is easy.

• Wired up the dimmer pots and interior light switches, then dropped the panel in to test them out.  While the panel was in, I ran wire for the accessory power jack and the music input jack next to it (though this wire may end up being a placeholder, if this wire is already in the harness from Stein).

• Ran a wire to each Pmag for the serial port connection.  I will bring each of these to a jack on the subpanel for ease of connection with the computer utility.  The rear-mounted APRS transmitter will have a similar jack on the baggage bulkhead for programming.
• Test-fit the CO/SpO2 sensor.  Can’t use washers on these screws, because the mounting holes on the piece are too close to the protruding bezel.  Decided I need to get some #10 capscrews for the throttle quadrant mount to the panel, which should work better than bolts due to clearances (sockets were getting wedged in place).

• Cut the plastic U-channels for the switch backlights, and painted them black.  Cut LED strips to length for each piece of channel (3 total), and soldered leads to them.  After testing them, it looks like another layer of paint will be necessary; the light bleeds through the sides of the channel.