I’m an unusual builder – I’m almost 3,000 hours into an RV-10 slow build, and I’ve never even sat in an RV of any kind, let alone flown one! I spent most of July on holidays in North America, including three days at Osh Kosh, and after the main trip was over I traveled to Vernonia, Oregon, where I flew the Factory RV-10 with Mike Seager.
Mike is a great instructor, and has been doing Van’s RV transition training for a long time. Despite some marginal weather at times, we managed to fit in five flights across the three days of August 7, 8 and 9, for a total of 9.2 hours RV-10 time in my log book. We visited 5 different airports during this time, plus the grass strip at Vernonia where Mike has his hanger.
It took me a few hours to catch up with the RV-10, I was hopelessly behind the thing on the first flight. It accelerates and climbs so quickly compared to the Cessna’s I’m used to flying, and the circuit procedures have a different slant as well. During an evening trip to Astoria airport, I finally “got it”, and in perfect conditions with the airport basically to ourselves, I did about ten “stop and go’s” in the fading light.
I’m a bit early doing this training, but couldn’t resist the opportunity to fly a few hours in the USA with such an experienced instructor. The Factory RV-10 costs U$75 per hour, wet (I think it has now gone up to U$80), which is ridiculously cheap especially by Australian standards. Mike explained to me that it is Van’s policy to actively encourage people to fly the aircraft, firstly in order to promote the sale of kits, and secondly to encourage builders to undertake adequate transition training.
I’ll probably do the same thing again in the Northern summer of 2020, when I hope to be close to first flight.
I had my third technical counselor visit on 25 June 2019. Since there are no counselors currently residing in Tasmania, I’m very fortunate that my TC, Brian, is prepared to fly down from interstate for the day. We had a good session on the Fuselage progress in the morning, went to lunch, and visited a friend’s RV-9A project in the afternoon.
I’ve been on a mission since April to get the fiberglass work on the Cabin Top and Doors behind me rather than in front of me. It’s been a bit of a marathon, the cabin top molding is not famous for its accuracy and everything has to be hand crafted to fit. Here’s the finished product:
I had planned to roll the thing in and out of the workshop to help with this work, but the weather’s been too cold to safely work with the plexi or cure fiberglass, so it’s all been done inside. I’ve had a pair of heaters going in the workshop 24/7 for the past month, and was finally able to turn them off last night. The shop vacuum copped a beating during this time, and I had to regularly clean out the filter.
Here’s all the steps I went through to get this job done. Skip to the end for the pictures.
1. Fit the rear windows
I used Lord Adhesive (available from Aerosport Products) for all windows. The forward surface of the rear windows needs to line up with the aft surface of the doors, which means spacing the windows up from the fuselage molding. I then built up the rear door pillar with a few layers of fiberglass cloth and flox until it matched. There is a flat spot on the left hand door pillar of all RV-10 cabin top moldings, this was the worst place and had to be built up about 5mm – too much for just micro/filler.
I used West Systems G/Flex with some microballoons to fill in any voids not filled with the Lord Adhesive, and trimmed any excess Lord Adhesive with a scalpel. I then taped and scuffed the window (and fuse), and applied 3 layers of fiberglass cloth on the outside. After sanding any high spots, and scuffing, I used regular West Systems epoxy with microballoons and Cabosil to fill and blend the outside surfaces into the cabin top.
2. Paint the inside door sills and cabin top pillars
The lower cabin top pillars had to be blended in, and painted, along with the door sills, to match the rest of the interior. This painting is best done before the front window is installed. Unfortunately, the inside of the cabin top and overhead is already finished, so I had to mask it all off with cardboard and tape. I didn’t want to have a yellow polyurethane primer leak splattered across the ceiling. This all took a fair bit of time, and I wound up spraying each side in sequence rather than together, because I didn’t trust myself leaning across wet paint to get to the other side.
The job took time but went OK, and you can’t tell where the paint transitioned into the existing painted part of the pillars.
3. Install the windscreen
Once again I used Lord Adhesive. It helps to have a second person helping, cleaning up any excess adhesive squeezed out on the inside using Q-tips and white spirit. I used a combination of clecos and weights to hold the plexi in position while the adhesive cured.
3.1 Extend/fill lower edge and prepare for fairing
I scuffed the upper forward fuselage area, acid etched it, and wiped some Alodine over it to prevent the oxide re-forming. I then filled the lower edge of the windscreen using Micro-balloons, with black dye to prevent it being seen from the inside. After the micro cured, I sanded it to align with the outer surface of the windscreen, taped off and scuffed the windscreen. All I used to figure the tape position was a cardboard cutout section with a 7 inch radius.
3.2 Construct the windscreen fairing
Once again using black dye. Preparation is the key to this layup, I cut all of the glass cloth strips, and allowed several hours to do this in one operation. It worked out quite well and a day later I sanded it into the correct shape, using a wooden block cut with a 7″ radius (using the band saw). I used a stick-on flexible perma-grit strip for this operation, which surprised me by staying in place. Gotta be very careful though, not to encroach onto the tape because the coarse perma-grit is a weapon.
After this I switched to 80 grit sandpaper, and finally 120 grit to carefully sand down to the top layer of tape. I used micro to fill low spots. It took a few iterations to get the entire fairing correct, and blend it into the fuselage at each side.
3.3 Glass in windscreen over the top
Fiberglass cloth across the top and down each side, once again fairing it with micro, matching it with the front edge of the door. To do this, I used packing tape on the door as a release agent, slathered micro through a section of the pillar, and closed the door onto it. The following day, a hard yank on the door would release it, and I can sand down any excess.
4 Door edges and cabin top alignment
Whenever I use packing tape as a release agent, I apply it over a layer of masking tape. It is easier to get off, and then any goo left behind simply comes off with the masking tape.
I worked sections of the doors at a time, applying micro to the pillar edges or anywhere that required building up, closing the door with packing tape in place, letting it cure, and then opening the door to release it. This is a good reason to leave the door windows out and fit them last – you’ve got the entire window opening to use rather than the door handle, and in some cases it requires quite a yank to release the door.
4.1 Door gaps, fairing across the top of the door
At this point, the doors closed properly but with basically no gap. Starting at the very top, I used a small piece of 120 grit sandpaper, and worked it from side to side through the gap, closing the door until it jammed, then lifting the door a fraction so I could keep sanding. I mostly sanded the cabin top – since it was micro and easy to sand, but also since the doors already had a nicely formed flat angle which I didn’t want to distort.
Once I could move the sandpaper side to side with the door closed and locked, I moved onto the front and back curves and did the same thing, working my way down each side in turn. Finally I sanded across the bottom and around the bottom corners, getting to the point where I could insert the 120 grit paper, and with a bit of friction still there, slide it all the way around the door.
I measured the 120 grit paper at about 0.01″ thickness. The gap will need to be wider prior to painting, but at this point I left it as is – as long as there is a gap the door is hanging freely, attached by the hinges and the door pins only. Setting up this gap allows the door to drop slightly, maybe a fraction of a mm. This required a bit more fairing work around the top of the doors, to match the door level with the cabin top.
4.2 Bottom of the doors
The bottom of the doors was a close match to the outside of the fuselage, aligned within perhaps 0.5mm across the entire length, but it is a simple matter to match it precisely. Once again, using packing tape as a release agent, I built up the door where required, and the surrounding fuselage area(s) where required, with a thin layer of micro, and then sanded it back to get an exact matchup. This introduces lots of pin-holes which of course have to be filled later.
4.3 Check the seal gap
Since the doors adjusted position a “bit” with the initial gap set, it’s important to go back and ensure that the “seal” gap for the McMaster seal is still correct – between 1/4″ and 5/16″ in my case. I made a few adjustments across the top on each side.
5 Fit the door windows
With the doors an exact match and a 0.01″ gap all the way around the doors, it was finally time to fit the door windows. These are the easiest windows to fit, you can take the doors off and use gravity to your advantage.
6 Optional – prime and fill pin-holes
I elected to spray on some primer and surfacer to seal everything up and fill almost all of the pin holes. I only sprayed two layers of surfacer, sanding most of it off each time. There are still some low spots, it’ll need more work prior to painting, but it’s good enough for now.
All of these operations took two months to complete, and it was with some relief that I took all the masking and protective film off, and wound up with a good result.
I agonized over how best to raise the airframe to install the gear legs. I gathered some family muscle to lift it up onto a workbench, but aborted the attempt after it became clear we couldn’t do the lift with enough control.
I borrowed a 500kg lift table, removed the handle, and made up a frame that provided support under both the main and rear spar. I wanted a backup in case there were any problems with the lift table, so I crudely extended the forks on the tractor, added a bit of padding, and held these an inch below the airframe, as shown. As it turns out, the table did fine and the tractor was not required.
I fitted the left main gear leg and wheel, then had to cut the old dolly apart (committed at this point!) to get it out of the way and fit the right main gear leg and wheel. After fitting the nose gear, I let the table down and the fuselage settled in a nose high position (because of the missing engine weight). It looks awkward like this, but it’s still quite a milestone to get it up onto the gear.
My current plan is to get the airframe up on the gear so I can roll it in and out of the workshop to do the remaining fiberglass work outside. I decided to do a trial fit of the Avionics before doing this, just to make sure everything fitted properly after riveting together all of the sub-panel brackets.
The trial installation took about 3 hours, and no adjustments were required. I only did the minimal amount of wiring to get power to the panel, installing a single master switch controlling the primary (left) system master solenoid. Power came from a car battery on the floor next to the baggage door. I left out the Transponder/ADSB system, the Avidyne IFD didn’t have a GPS antenna, and of course with no engine there were no EMS sensors. I taped a COM Antenna, and the Dynon GPS puck, onto a chair outside the workshop. I ran the ADAHRS cable through one of the conduits and connected the primary ADAHRS only, sitting on a shelf in the rear. Didn’t worry about the harness cables much, just crammed them in – a real installation will take a lot longer when it happens.
It all worked at first turn-on, apart from warnings associated with the pieces that were left out / not connected. Nothing calibrated but I was able to use the COMM’s, enter flight plans, wobble the ADAHRS and see the screens update correctly etc. It was a useful exercise and helped firm up how I was going to route some of the wiring.
Now I get to take it all out again (which won’t take long) and get back to the plan – up on the gear and a month or so back in fiberglass hell.
Now that the upper forward fuselage assembly is riveted on, I can go ahead with the firewall insulation, using the Titanium foil and 1/8″ Fiberfrax I had previously prepared.
In order to prevent the Titanium from puckering, I used 1/8″ stainless steel spacers (available from McMaster Carr) for all #8, #10, 1/4″ and 5/16″ holes, and stainless steel washers for larger sizes. I used RTV to hold the spacers “in place”, a few swizzles of Fire Barrier 2000+ to hold the Fiberfrax in place, and then put on the Titanium. I used machine screws to retain the Titanium in place, these will later be replaced by whatever their respective position calls for. There’s a few pulled rivets across the bottom, and for most of the pass-thru’s I had left one rivet position open so that retaining rivets can be used here as well. The rivets I used are stainless steel, and have a closed end cap, so they should seal up quite well.
I installed the A/C pass-throughs and steel AN fittings for the duplex fuel system, and riveted on the oil cooler mount. I previously made up a Titanium insert for the center recess. I subtracted 1/8″ all around from the recess dimensions, and made the insert accordingly. The thing’s a work of art, but it turns out I should have allowed more wiggle room so I’m going to toss it and make up another one.
I went on a bit of a campaign mounting various items on the firewall, to get them off the shelf and out of the way. Finally, the engine mount went on and that’s another large item no longer on the floor.
I moved the paint booth out and tossed it in the farm shed. I don’t really have much use for it in the coming months, and moving it out clears up a lot of room in the workshop. At the very least it needs re-lining, it’s more like a dark room these days. It might get torn down, I think its usefulness is over after four years of dedicated service – an entire slow-build RV-10 got primed in that little paint booth!
With all the avionics in hand I decided how everything needed to fit behind the panel. This included not only the avionics, but also the SDSEFI system. Cable routing is another consideration – D connectors, and in some cases a “straight” section of cable running into the D connector – have to be accounted for. Suffice to say, the final layout turned out to be different than the layout I had previously worked out simply based on box dimensions.
I made up brackets for securing the rear of the IFD GPS chassis, and added stiffeners to the sub-panel where required in accordance with Van’s guidelines. I had to mount one item – the secondary system voltage regulator – on the back of the sub-panel. To make it easily removable I added nutplates to the mounting flanges. These will be easy enough to drill off and mount on another regulator if/when it must be replaced. I also drilled two fan mounting holes in the top skin, using a circle cutter in the drill press set to 250 rpm.
Once I was happy with all of the brackets and stiffeners, I primed them, riveted together the forward front fuse subassembly – including all of the brackets and stiffeners – and painted the exposed interior and top shelf area in a flat black polyurethane.
While the forward fuse was still open, I trimmed and fitted the Aerosport interior side panels, installed nutplates for these side panels, installed the NACA vents, and installed the rudder panels for the last time. I also completed all of the tunnel work, permanently installing the brake lines, fuel lines, fuel filter and wiring for the fuel pumps.
Finally the time came to rivet the subassembly onto the fuselage. One advantage of the Control Approach rudder pedals is that access is quite good through that area, once you’re upside down with your head under the panel. The riveting went fine and I was also able to complete the firewall riveting, including the brackets and spacers I had previously made up for the Skybolts.
Next job is to fit the firewall insulation and engine mount.
Last October I decided to use Advanced Flight Systems for the Avionics. They were great to work with and were able to take my hand written sketches, various CAD drawings and models, E-mails, and verbal descriptions and turn it into a coherent package of avionics and panel insert designs.
I signed off on all the drawings after about a month of dialog and more or less forgot about the whole thing until a wooden crate arrived here today containing the panel and avionics. AFS did a great job of packing it all up properly and everything arrived in pristine condition.
With all the avionics now in hand, I can finally work out where to mount the various boxes behind the panel, and do the necessary sub-panel cutouts and reinforcement. Between all the avionics and the SDSEFI equipment, there’s quite a lot to pack in behind the panel.
Apart from checking that everything arrived OK, I temporarily mounted the TFT display bezel on top of the LH panel insert. It took quite a bit of CAD work last year to ensure this bezel would squeeze in above the AF5600T EFIS, and match the contour of the panel insert. It fitted perfectly. I need to buy some black S/S #6 screws, so that the four mounting screws melt into the background rather than shine in my face.
I’ve fitted the cabin top – for good. It’s riveted on and retained with structural epoxy, so it isn’t coming off again. The RV-10 is often described as the aircraft kit that is 90% metal, and 80% composites. The cabin top goes on and off many times before it is “right”. I finally decided there was no reason for it to come off again, so … on it went. This time I scuffed the door channels and slathered on some flox, dropped the cabin top in place, did up all of the bolts along the door channel and installed rivets along each rear side of the cabin top. Now I have to fill the vertical parts of the door channels with structural epoxy, fit those bolts, and then finish the inside of the door channels with micro, fill primer, then prime and paint to match everything up with the already-painted cabin top interior.
I also primed, assembled and painted the tunnel cover pieces I’ve had laying around for a few months. These are cut and modified because of the control approach rudder pedals, which require slots and doublers in the front most part of the tunnel cover. The spray booth has just about outlived its usefulness, so I’m going to move it out of the workshop to free up some room.
I’ve been working on the firewall insulation. There’s a lot of material on VAF about this, I won’t repeat it here. Suffice to say I’m using an insulation material called Fiberfrax, 1/8″ thick, on the outside of the firewall. In order to hold it in place, a thin metal foil layer is required. I’m using 0.008″ thick Titanium for this layer (I previously bought some 0.002″ Stainless Steel foil but decided I couldn’t work it without having it crinkle up and/or tear. Impossible to drill a hole through it). The main purpose of firewall insulation is to give me some time to get the aircraft on the ground in some sort of controlled manner, in the highly unlikely event of an engine fire. A secondary purpose is to minimise the amount of heat that can be transferred into the RV-10 tunnel.
I found the best tool to cut the Titanium foil was an ordinary pair of scissors. Drilling small holes wasn’t a problem, but enlarging them with drill bits is not possible. I used a series of reamers for the smaller holes, the angled end of the flutes works well. To drill a #12 hole, for instance, I would first drill a #42 hole, then #39, #35 using drill bits, then #30, #19 and finally #12 reamers. The back of the foil must be supported of course.
For larger holes, a step drill works, but to finish the hole or enlarge anything beyond around 9/16″, I used a 1/2″ round sanding attachment in a die grinder. These wear out quickly, I went through around twenty of them. Doing these large holes with the die grinder worked well, as long as the foil was supported right up against the stainless steel firewall.
In an ideal world, all of the firewall nutplates and pass-through positions would be known when the firewall was laying on a bench, before ever being attached to the fuselage. That doesn’t happen, so I had to find a way of accurately drilling holes through the foil for all of the nutplates etc. To do this, I 3D printed a lot of disposable drill guides. For any purpose, I designed a drill guide, printed it, and used it to accurately drill a #42 hole through the center of whatever I needed to. In this way, I worked around the firewall and made all of the holes required in the Titanium foil. I used #6 screws through the AN3 nutplates to hold the foil in place while I worked on it, and clecos where appropriate.
With the foil prepared, I cut the Fiberfrax to shape, sandwiched it between the foil and firewall, and then worked my way around all of the holes, cutting the Fiberfrax as necessary with a sharp modelling knife. For the engine mount points, I completely removed the foil and ‘frax. All of the gaps will be filled in later with Fire Barrier 2000+.
I then set the Fiberfrax and foil aside. I can’t attach it permanently until the upper forward fuselage assembly is riveted in place. In fact, all I seem to have done for months now is to prepare parts, and set them aside.
One of the downsides of adding firewall insulation like this is that it makes future firewall modifications difficult. It is possible to drill through the foil and firewall, but deburring is a problem. I tried to anticipate everything I could, and for pass-throughs I put in more than I needed, it’s easy enough to plug up unused pass-throughs. I also made a separately mounted plate that attaches to the right side of the firewall, for mounting electrical components on. At some future time, if the electrical requirements change, I can simply make up a new mounting plate for them, rather than rely on firewall mounted nutplates for each individual component.