Joshua's RV-9A Project

The three P’s of almost-ready-to-assemble-something.  Etched the remainder of the canopy frame parts, then primed, and painted the visible surfaces.

Drilled the rivet patterns into the skirt spacers, then match-drilled to the side rails.  The spacers will be riveted to the side rails with several keeper rivets along their length, then the side skirts will be fit and back-drilled from the inside.  Deburred all the holes, and that is a lot of holes.

Trimmed the rudder cable exit fairings (picked up at OSH) to a curved shape, rather than a rectangular one.

More work on the canopy frame… fitted the stiffener kit to the frame, then took everything apart for deburr/dimple/etc, and prep for primer.  The plan is to rivet this thing together, and get the aft top skins on, then fit the plexi bubble.  The stiffener kit wasn’t too bad to install, though it has plenty of notches to deburr; the worst part is bending the flanges around the 9 lightening holes.  I broke a couple boards with notches (including an oak piece), then used a 3″ hole saw to make a giant dimple die of sorts, clamped one hole at a time, and whacked it with a 3# hammer.  That seemed to do the trick.  They’re not pretty like factory-formed ones, but the do stiffen up the pieces considerably, and they’re hidden behind the panel anyway (except when the canopy is open).

Also riveted 2/3rds of the rearmost top skin, while Allison was looking for a reason to be in the garage (since it was cooler than the house in the 95° heat.

Expecting to be out of town again for half this week, and busy some evenings, but with any luck, the frame will be complete by mid-next week, and work with the plexi might still have a shot at being done before the fall temperatures set in.

A few more canopy frame tasks tonight — fabricated the wedges that go where the side rails join to the front weldment, along with the nutplate plates for securing the aft lift strut mounts.  Drilled the wedges to the frame, then drilled the strut mounts to the canopy decks.  Playing with the geometry, I discovered that the 1/8″ inboard offset I built into the frame (for Sikaflex) causes some trouble with the lift struts in the plans orientation (with the ball stud on the outboard side of the mount), so I removed the two spacers from each side, and placed the ball studs on the inboard side.  It looks like it should work this way.  (I later saw that the Flyvans.com guys made the same swap while fitting their canopy.)

Still working on the canopy frame: today’s session involved fabricating the mounts for the lift struts.  The forward mount is made from a thick block of aluminum which is drilled and tapped, and affixed to the canopy frame with screws.  The aft mounts were fabricated but not installed yet; they will eventually be screwed to the canopy decks.  I plan to fabricate a “nutplate plate” for fastening those blocks (as many others do), rather than fuss with washers and nuts in the tight space up behind the decks.

I also fabricated and installed the forward canopy stops, a modification that is gaining popularity.  I found the bolts at Menards, they were called “elevator bolts” — their large diameter flat head should provide a nice bearing surface for the canopy frame to push against.  The theory here is that by providing a hard point for the canopy to stop on, you eliminate some of the fit problems caused by the pressure of the lift struts pushing the frame forward in the down position.  It consists of an angle, a bolt, and 2 nuts per side, a pretty simple mod which should be worth it, if it helps even a bit.

Back from Oshkosh, it’s been a little rough getting back into the shop.  Talked with lots of vendors at the show, but didn’t find the deals I was hoping for, though I got most of the information I was seeking, and made some connections.  I expected to be highly motivated when we got back, but strangely the opposite happened.

Regardless, I cleaned up the disaster of a shop today, and went back to work on the canopy frame.  Fit the rear bow to the rollbar, fit the side weldments along with the spacers to allow the Sikaflex bead, and drilled the splice plates.  Then, the whole works is removed for deburring and riveting; I think this is also the point to install the stiffener kit and the struts (neither are mentioned in the manual).  I’m using the Flyvans.com guys log as a guide for the canopy work, since I will be gluing the canopy as they did–there are many logs of the gluing method for sliders, but not many for the tipup.

The main differences so far are that the roll bar and rear bow were built slightly narrower than plans (which meant also that the brackets were inboard, which required the fabrication of a spacer to sit outboard of the brackets, rather than filing the aft end of the bracket), and the forward splice plate of the canopy side rails, where the side rails are offset inboard by .125″ using a spacer.  This is to allow for the required .125″ bead width of the glue.  To make up for the inboard offset, a corresponding .125″ spacer must be installed between the side rails and the canopy skirts…I ordered a pair of the .063″ strips that are used in building the roll bar, as they’re just the right width for the job.  Cutting each in half and doubling it up gives a nice .125″ spacer for the skirts, and it seems to be working well so far.

In the odd jobs category, installed the last three nutplates on the roll bar brace, having received my supply shipment from Van’s.

More work on fitting the canopy frame, which began by drilling holes in the splice plate, fabricating spacers for the goosenecks, and getting the frame positioned correctly to match the fuselage width.  That done, the holes were deburred and the forward portion of the frame riveted: the bows, splice plate, spacers, and goosenecks.  The whole business was then fit to the fuselage again and tweaked for fit.  The holes for pivot bolts were marked with a long 1/4″ bit by peeling up the edges of the forward top skin, then the assembly removed to drill the pivot points.  Bushings were pressed in with the hand squeezer…both sides turned out well, with good edge distance.

That done, it was back to the fuselage again for another round of fitting.  The seal support angle needed to be trimmed to allow the canopy frame to move, and the front of the canopy skin filed down to widen the gap enough that the skin doesn’t catch the front skin and kink the edge.  After another couple of on-off cycles, I think I have the front fitting decently; supposedly this all changes when the struts are fit, but I see no mention of that in the manual, so I will have to see when that’s best done.  I do plan to add the canopy stop bolts that have become popular, to provide a positive forward stop to counteract the “thrust” of the struts when in the closed position

I will follow the lead of Chad Jensen and the Flyvans.com guys, filling the gaps at the outboard three holes with washers, so I put stacks of 960-10′s in there for now.

Installed various tie-wrap bases for the tailcone wiring runs, and pulled the aft nav/strobe, pitch trim, pitch servo, VOR and transponder antenna cables into the tailcone.  Installed standoffs for the static line in the tailcone and secured the line, checking for clearance with the harness anchor bracket.  Installed the ELT mounting bracket.

Worked on fitting the canopy frame by clecoing the skin to the forward frame weldment and fitting to the fuselage.  After several on-off cycles and adjustments, it was fitting pretty well, so the splice plate was drilled to the forward bows.  Removed the skin and cleaned out the chips, then re-clecoed and checked the fit on the fuselage.  Fits the same, with the usual slight gaps at the left & right front sides, that require spacers under the front skin.  An initial check of where the hinge holes will fall shows that the holes are almost dead center in the hinge goosenecks…I’m pleased with that, though I do need to fabricate spacers to go between the goosenecks and the forward bows (that distance is set by the holes in the skin, and mine has a gap…no biggie, it looks like a piece of .063 and .040 will fill it nicely.

The issue at the moment with the canopy frame is that, for the outboard three holes of each side’s aft tube, the skin does not sit down to the tube…there’s quite a gap.  I’ll have to read up on what others have done here, whether make spacers, omit these holes, or what.  Also trying to figure out when the canopy stiffener kit should be fit, as there is no mention of it that I can find in the manual.

Finished off the installation of the main canopy latch by cutting the slots in the fuselage side skin; used the traced template to drill the pilot holes, then masked the area to be cut with blue tape, made two passes with a Dremel cutoff wheel, and worked with needle files to finish it off.  Not bad.  Drilled the mechanism to the skin, dimpled with the pop-rivet dimpler, and countersunk the angles, before fitting the aft part of the mechanism.  All in all, an easy piece of the puzzle, and it operates well.  I did have to slightly enlarge the aft slot top to bottom to prevent binding and scraping of the handle; I think there is a slight bit of variation to the straightness, and I couldn’t convince it any straighter.  No biggie.

Note: when you go to rivet the little screw plate to the top of the flap motor mount channel, use flush rivets, rather than universal heads…I ended up drilling out those three AD470′s and replacing them with 426′s, because they were rubbing on the torque tube for the canopy latch.  Even without the rivets, the tube rubs slightly on the channel; I think this is a common problem.  I’ll probably stick a piece of UHMW tape on the channel there to avoid chafing, unless a better solution comes to light.

Pulled out the canopy frame to look at how it goes together; did a couple common things: filed the welds flush, chamfered the forward edge of the hinge ears, and chamfered the aft edges of the plastic hinge blocks.  This allows the ears to guide themselves into the slots.

Time to check off the laundry list of little fuselage tasks to get ready for some riveting:

• Removed the latch mechanism, disassembled for prime/paint, and deburred.
• Removed the forward top skin and subpanel assembly, spot primed scuffs, and set aside.  Debating whether to paint the stuff aft of the subpanel or not.  (Note to self: still need to ream the outer bulkhead holes)
• Removed the roll bar and brackets for prime/paint.  Deburred and cleaned up shavings from that installation; touched up paint on the trimmed corners of the seatback rests.
• Removed the mid top skin for painting; lifted one side of the aft top skin for wiring/plumbing access.
• Pulled the static line with the hole drilled in it and ran a replacement line.
• Spot primed aft bulkheads and vacuumed the aft fuselage.

Etched and primed all the removed parts; rattle-can painted a few little things, waiting on the rest–I need to pick up another quart of the Rustoleum brown, because it goes on better with the sprayer than from the cans.

The plan going forward is to run some wiring in the aft fuse, then close that up, along with the structure of the subpanel, to prepare for fitting the canopy frame.

Spent most of today working on the canopy hinges and latches.  First order of business was to drill the 1/4″ holes for the pivot pins, using a 12″ drill bit I picked up.  That done, I built up the mechanism that inserts and retracts the hinge pins.  This required cutting off the threads and rounding the ends of the pins themselves, fabricating the pushrods, and assembling the bellcrank mechanism.  The goofed-up hat channel was replaced with a shorter piece, cut from the section that was cut off before.  This should work fine, since its only purpose is to hold the bellcrank…I had enough material left to pick up the top three rivets on each side.  Installed the lever on the bottom of the bellcrank, but not the tube that runs aft; instead, I made a little handle that attaches to the lever, and has a tab with a hole to secure it to the subpanel.  I put in a nutplate for a #8 screw to hold it there; a nice improvement would be a thumbscrew with a #8 thread, so that it would be easy to undo without having to mess with a screwdriver behind the panel.  This tab will be easily reachable, since this is open to the sky when the canopy is open.  (The tab idea was shamelessly stolen from another website, though I can’t remember where I saw it… Flyvans.com, also a good resource for tip-up canopy Sikaflex tips.)

With that mechanism rigged, on to the next thing…the main canopy latch.  First up is to fabricate the control lever, which allows the pilot to latch/unlatch, and also protrudes through the side skin to allow the latch to be opened and closed from outside of the plane.  The upper and lower angles were fabricated, latch arms deburred and straightened, and holes drilled–bottom first, then match-drilled to the top angle.  (Hint: I use my back-rivet plate as a true surface to verify that things are flush if needed for match-drilling.)  I stacked up four layers of masking tape on the inside face of the angles to allow for the thickness of primer and UHMW tape to be applied later.  For fun, drilled the yellow latch knob to the lever.  And finally, traced the template for cutting the side skin, which I’ll get around to tomorrow.