Painting the wings [120.0 hours]

I haven’t posted for a long time, but have been pushing along various jobs including the baffles, wing root covers, fuel system and painting various small parts such as the flaps, ailerons etc. While the wings were still pinned on to the fuselage, I did a complete fuel system and tank test, by filling the wings with fuel and running the fuel pumps each side through the entire distribution system, except for the final lines to the injectors. No leaks, good fuel pressure, no weeping rivets. After this, I took the wings off to paint. Since this was a major activity I’m posting some details here.  If you’re not interested in the details, pictures are at the end of this post.

I thought about how to set the wings up for painting quite a bit, and finally decided to make a set of stands to hold the wing in place vertically, with the nose highest. I discounted more complex schemes such as rotisseries, RV-10 wings are quite large and a rotisserie would need to be quite robust. Apart from which, it is unnecessary. Painting the large wing surfaces vertically gives you the easiest access and optics to maintain a wet edge, and in an amateur setup without highly filtered air it exposes the minimum area for dust to “settle” while the paint is drying.

I was going to build a booth out of structural pine and plastic, but after pricing the required material I elected to save the hours and buy a cheap inflatable booth. It’s large – 10m x 5m – and the blower to keep it inflated is noisy, but it was easy to set up in the hangar and the filters were quite adequate.

I put a lot of thought into how the stand works, and then built it out of scrap material. There is a stand for the wing root (main spar), a stand for the outboard (light) end of the wing, and an intermediate piece of stand which allows me to support the wing after the white is painted, so the end stand can be temporarily removed and the wingtip fitted for taping. The two ends of the stand are tied together with a pair of 75x35mm pine pieces, 4 metres long, and the resulting “channel” can be lined with plastic to catch the water runoff from the acid etch and rinse operations. This was another reason for doing the wing vertically – I could do every operation from acid etch to final paint in the same stand, with no changes apart from the switch while the wingtip is temporarily put in place for taping.

I painted one wing at a time. Spraying takes next to no time at all, but taping off takes many hours and I didn’t want to have to do this for both wings at once. I did the left wing first, then after learning a few things did the right wing slightly differently. It took 3 (long) days to do the right wing, from start to finish, with four colours. Here’s the order of events:

  1. I scuffed the top side of the wings while they were on the plane, and the bottom side of the wings on a pair of workbenches after they were removed. I de-greased both sides at this point, so that they were “substantially” clean before moving the wing into the booth. I also taped up both ends, all the inspection plate holes, fuel drains etc. at this stage.
  2. Tape drop cloths to the floor of the booth. Tape builder’s plastic to the water channel, making sure it is pressed down inside the channel. Use minimum tape, because it has to be taken up again while the wing is in place.
  3. Move in the wing stand and screw each end to the channel pieces.
  4. Move in the wing. It’s a two man operation to lift the wing off a pair of workbenches and onto the stand. The poor guy holding the outboard end has to hold it while I secure the main spar. I inserted 3/8″ teflon tubing into the outermost 3/8″ holes on the spar connection, and used batton head screws with washers (and ample layers of masking tape) to secure the wing root in place. Then I move to the outboard end, hold the wing up, and the other guy can release the wing and insert the support for the far end of the wing, clamping it into the stand and screwing down a holding cap. The support piece has padded surfaces for the spar, two of them separated by about a 2 inch gap, for the outermost two bays of the wing. With this support in place, I can release the weight and the wing is fully supported, and moreover is fully exposed to be able to spray all surfaces.
  5. Do any remaining tape up for paint. Fuel cap holes, and a few other bits ‘n pieces.
  6. Fully degrease the wing. This is easy since it was mostly done before moving the wing into the booth. Don’t forget to pay special attention to the skin overlaps, where grease can stick to the edge.
  7. Tape up the seams so the acid etch doesn’t penetrate into the wing interior (much). Tape over the fuel cap holes, and the the inspection cover holes etc.
  8. Do the acid etch. I used cheap 2 litre and 5 litre garden sprayers, the type you pump up to spray. The 2 litre container was for Alumiprep 33 solution (about 50/50 with distilled water), and the 5 litre sprayer contained distilled water. Spray the acid at low pressure horizontally across the wing – it’ll all run downwards – and catch it with the 3 inch brush using horizontal strokes. Wear safety glasses. Work your way from the top to the bottom. I did half of the length of the wing at a time, front and back (spraying near the top oversprays to the other side), twice, allowing time for the acid to work, then rinsed it all off with the 5 litre sprayer, never allowing any of the surfaces to dry. The first acid you spray on will “break” and quickly run downwards in trickles, which is one reason you need to keep brushing horizontally to spread the acid around. Once it has had a chance to work, the water will not “break” much or at all. With one half of the wing done, front and back, I switched to the other half. I kept going back and spraying water over the first half, to keep it all wet (oxide won’t grow back under water). Once the wing was all done, the channel was full of acid + water runoff, the entire wing surface was wet, and there was also a bit of water lying around outside the channel (inevitable) but not much. In total I used about 1.5 litres of acid+water solution and 5-6 litres of rinse water (I had to refill the container once, a 10 litre sprayer would have been better). Now let it all dry.
  9. After 5-10 minutes, I removed all the wet tape and rinsed around the exposed areas where a bit of acid had penetrated in and around the tape, using a bit more distilled water in a small squirt bottle.
  10. Let the wing dry. I used some cleaning cloths to run along the bottom where the skins run behind the aft spar, since water tends to accumulate at this bottom (aft) edge and take a lot longer to dry. Heaters may be necessary if the weather is cold. Hot days are best, get the thing dry as quickly as possible because the oxide is growing back…
  11. As soon as the wing is dry, spray EAP-9 (or your adhesion promoter product of choice). You only need a very fine mist of the EAP-9 product. Allow to dry.
  12. Move in the wingtip. Spray the primer on both the wing and tip. I used PPG CA7700B primer, as part of the system I used. The primer only needs to be sprayed on as a very thin coat – almost translucent. Allow to dry.
  13. Remove the water. You can “roll” the plastic from the outboard direction, then using a small cup and a bucket, get all the water (and primer overspray, and acid) out of there. I did this later for the left wing, but it’s best to get it all out of there asap because it’s a mess. Be careful not to splash any of this toxic mixture on the wing.
  14. Wet down the floor (it contains a lot of primer overspray) and spray the main topcoat (in my case, white). I used PPG CA8800 paint. It’s expensive paint, but easy to use and will outlast me. I sprayed two coats using the CT2 thinner, 40 minutes apart. It took me 15 minutes to spray the entire wing and wingtip (I’m slow at this), so plenty of time between coats to clean the spray gun and mix up the next pot of paint (induction time is zero). The coats need to be thin, this isn’t a truck. Although it isn’t necessary to clean the entire gun between coats, I’ve always done so. Hint: After the first coat (only), as you finish cleaning each part with gun cleaner, rinse it in Acetone. This rinses off the gun cleaner, which can be a little slow to dry (in my case), and the Acetone will evaporate quickly. That way, when you reassemble the gun for the second coat about 20 minutes later, all the parts will be bone dry.
  15. As soon as the white topcoat is “dry to tape”, or a bit more, re-configure the stand so the wingtip can be temporarily fitted. This step can be skipped depending on your paint scheme. In my case I had fairly acute sweeping angles of grey accent paint crossing the wing-wingtip boundary, and I wasn’t confident of getting these right without taping up the entire shapes with the wingtip in place. The mid stand piece I made was secured to the bottom channels, the outer most flap support, the wing tie-down hole, and the aft spar near the inboard aileron hinge bracket. I’ve included pictures showing how this was all done. I used a piece of 3/8″ fuel line inserted into the flap bracket hole to protect it from the screw, with plenty of soft (baffle material actually) padding and washers to spread the load, and of course masking tape.
  16. Now is a good time to tape down some new drop cloths on top of the old ones, at least in the outboard half of the wing where you’ll be mostly working from now on. If you have a poor man’s spray booth like mine.
  17. I made some patterns out of brown paper (and tracing paper) for where the various colours go. It’s a lot easier to do these with the wing on the plane, or the bench, and without the time pressure of spraying paint. Using the patterns, I taped off near the boundary of each colour. I use 3M 233+ (green) tape for anywhere that tapes on to freshly painted surfaces, and cheaper tape anywhere I’m taping down onto the top of the green tape, or other covering material. Once the basic shapes are outlined in tape, carefully slice the tape with a sharp knife on the wing/tip split line, and remove the wingtip. Re-configure the stand back the way it was (to make it easier to cover the rest of the wing up for protection from overspray.
  18. Tape everything up. This is the part that I found takes a long time. Tape things up so you can easily remove tape covering successive colours, in the order you’ll spray them.
  19. Tape up the edge(s) you’re doing, in my case the second colour to spray was blue. I use 3M 471 vinyl tape for the edge work. It’s best to avoid crossing rivets or seam boundaries, but in some cases this is inevitable.
  20. Clean the exposed (white) surface with isopropyl alchohol. It’s best to avoid touching any surface at all, but I can’t manage the taping up wearing gloves so it’s inevitable to get a bit of a touch somewhere and this has to be cleaned up. Press all the blue edge tape in.
  21. Go mix the paint pot. Spray the colour (again, in my case, two light coats 40 minutes apart). the very last thing I do before spraying the colour is to re-press all edge tapes, with a gloved finger. A final wipe with a tack cloth is also a good idea.
  22. At the “correct” time, peel off the edge tape. It should be prepared so as to make it easy to peel off, and the direction should be correct (towards any point in the pattern). In my case I found 75 minutes after the second coat was about the right time, at 20-25 degrees ambient. Clean up any paint that (for example) ran around a rivet the edge crossed, using a Q-tip and thinners. It’s far better to deal with any artifact now with a Q tip than later with an air brush. In some cases the air brush will be inevitable.
  23. If there are more colors, once the paint is dry-to-tape, rearrange the taping and repeat the above process for the remaining colours. I was able to spray two colours per day, white+blue on day 1 and dark+light grey on day 2.

It was quite an effort to do all this for two wings, but I’m happy with the results. It’s an amateur job of course, but close enough to what a pro would do at a much cheaper cost in labour. The paint I used is buffable, if I want to work on any areas later. There is a buffable clear coat available for this paint system, but I elected not to spray the clear, due to the extra expense, weight and the fact that I’ve never successfully sprayed clear coat before and didn’t want to add more work to the job.

I’m having a break from the project for a few weeks, before getting on with preparing and painting the fuselage.

  • lw1
    Ready for acid etch, seams taped
  • lw2
    Acid and water runoff collected in channel
  • lw3
    Sprayed on EAP-9, ready for primer
  • lw4
    After spraying primer
  • lw5
    Wingtip primed
  • lw6
    White topcoat sprayed on wing and wingtip
  • lw7
    Middle support stand
  • lw8
    Middle stand detail - flap anchor screw
  • lw9
    Middle support stand detail - tie-down bolt
  • lw10
    Middle support stand - bottom support
  • lw11
    End support removed
  • lw12
    End support removed
  • lw13
    Wingtip fitted with a few temporary screws
  • lw14
    Pattern for blue
  • lw15
    Blue transition tape marker
  • lw16
    Tape markers for grey details
  • lw17
    Wing and wingtip seperated
  • lw18
    Masking off remainder of wing
  • lw19
    Blue painted, vinyl edge tape removed
  • left_wing_and_tip
  • lw20
    Left wing complete, back in wing stand
  • rw1
    Right wing completed (top)
  • rw2
    Right wing completed (bottom)
  • rw3
    Right wingtip completed
  • bw1
    Both wings finished, back in the wing cradle

Move to the Hangar, and subsequent works [100.0 hours]

In early May I moved the project to a Hangar at Hobart Airport. A kind neighbor donated his time, truck and float to perform the move. One wing missed out going when the loading plan went a bit astray, and we moved that on a different truck a few weeks later. It was a bit unnerving to see the project tied down on the float and being driven on gravel tracks out of here, but my neighbor’s 50+ years of experience in the trucking industry made it all seem easy.

I spent much of May into June moving the contents of the workshop to the Hangar and setting everything up there so I could continue with the build. The workshop at home looked like a war zone during this effort, it was certainly high time for a clean out. A resident rat had been living a comfortable life in a cluttered corner of the workshop, it was last seen running for cover under some bushes in the outside garden after being evicted.

I pinned the wings on, again with the help of several neighbors, and have since finished fitting the flaps, the wing root fairings, the wingtips, and the wing root fuel lines. With the flaps fully retracted in the reflex position, and the ailerons rigged to match the flaps (with elevator neutral), I split the rear edge of the wingtips with a fine hacksaw blade, set them in place to match the ailerons, final drilled the rivet holes for the wingtip ribs while being held in place, and re-glued the rear wingtip inner edge with epoxy. After this set, I removed the wingtips, stood them up and reinforced the rear edge with flox and a layer of fiberglass. Compared to the initial condition, I moved one wingtip down about 4mm and the other down around 7mm; they were out by enough to annoy me and fixing them was quite easy.

Winter has been brutal in that tin Hangar. Thermals and heated vests only go so far. After the workshop at home was cleaned up, I pitched a marquis tent inside it. I dismantled my old priming booth, and recovered the wire table to use for spray painting parts. With two electric oil heaters going, I was able to keep the environment inside the tent at a high enough temperature to spray paint some parts. I painted a few simple one-colour items – the horizontal stabilizer, elevators and some fiberglass parts to make a start on the daunting prospect of painting the aircraft. The transportable parts I’ll paint at home in the coming months, the wings and fuselage I’ll have to paint at the Hangar, this will have to wait until summer so I can get a reliable block of warm weather. I’ll build a temporary booth out of wood and plastic film at the Hangar to do this work, with filters and fans to provide some airflow for over-spray removal.

In the meantime, I continue to grind away at the never-ending list of things to do. Now winter is officially over, the days are getting longer and progress should pick up.

  • move1
    Loading up
  • move2
    On the move
  • Second wing delivery
    Second wing delivery
    Delivering the second wing and stand with my neighbor's classic flatbed truck
  • wing1
    Wings pinned on
  • flap1
    Fitting the left flap
  • flap2
    Fitting the left flap
  • wing_root_fairings
    Wing root fairings, and temporary anti-slip
  • tip1
    Fitting the wingtips
  • tip2
    Fitting the wingtips
  • tips3
    Fitting the right wing tip
  • tips4
    Re-gluing the right wingtip
  • paint_hs
    Painting the Horizontal Stabilizer
  • paint_elevators
    Painting the elevators and trim tabs
  • paint_ailerons
    Painting the ailerons
  • paint_rudder_fairing
    Painted bottom rudder fairing

On to the final lap [87.0 hours]

With the bulk of the Avionics, wiring and software work done, I’ve spent the past few months back on airframe and related work, pushing towards the point where I’m ready to take everything to the hangar. Lots of small to medium scale jobs, chipping away at the overall task. Here’s what I’ve done:

  • Wing wiring. I ran and labelled all wiring for both wings, and temporarily hooked up with wingtips, pitot, etc. and all connections to the fuselage, with the wings still sitting in the wing stand. I tested all functions, and found two minor issues – the landing and wigwag switches were reversed, and I had forgotten to run a wire from right to left side for the strobe synchronization. Apart from this, all good so I could now close up the wings.
  • Riveted bottom wing skins. This was a tedious job, which we did with each wing in turn laid flat on a pair of workbenches. The first wing took about 12 sessions across 4 days. Then we had a break for about a week, before tackling the second wing which took about the same number of sessions but stretched across a few extra days. Not many pictures of this, didn’t do much that deviated from the instructions, but due to the size of my forearms I found it impossible to reach down to the rear spar between the close-together ribs under the wing walk doubler. I made up a special long bucking bar, by taping a tungsten bar on the end of the RV-10 elevator bucking bar, which I could then hold in position. Not a great option, but good enough to get the job done cleanly.
  • Clear coat and install the centre console. This went in OK, as did the headset panels I previously designed and made up. Also included in this area are the throttle and pitch controls, fuel valve extensions etc. It’ll be a mild nuisance to take apart at each annual, but with the tunnel cover breaks I have in place won’t be too bad. The finished look is great.
  • Fitted the Matco brakes, brake lines, and filled the system with brake fluid. I replaced the standard O-rings in the Matco brakes with Viton rings, for high temperature stability, since I never need to worry about deep sub-zero conditions in Australia. I used Royco 782 brake fluid. No leaks, thankfully.
  • Wheel spats. Another tedious activity. I mostly followed the plans, except:
    • I used the RVbits leg intersection fairings, because the ones supplied in the kit are terrible.
    • I used a laser level for all the relevant measurements, much easier than plumb bobs etc.
    • I found my jacks crept down a bit over time, which is a problem for doing the spats because it takes a succession of fiberglass jobs over several days to do it all. I made up a wooden stand, that went under the main spar (with 3/16″ of hard rubber padding), used the jacks to raise it all, then lowered the stand onto wooden boards. A few Alclad shims under one side was enough to level the airframe in roll, and a tie-down on the tail was used to get the pitch into the cruise attitude. When it came time to do the nose wheel, I raised it higher by adding an extra board under each side and re-leveling.
    • I split the lower main wheel leg intersection fairings on each side, and fiber glassed the fairings into the respective front and rear spat halves. This is a bit more work to get right, but makes it simpler and easier to remove and reinstall the spats.
    • I painted the inside of the spats. I figure they’ll fill up with dirt and mud and require cleanout occasionally, and this seals up the fiberglass interior to make it easier to wash any accumulations away.
    • Since I’m using the Matco brakes, I had to cut out a section of the main wheel fairing brackets, to clear the brake line connection. I reinforced the area with some scrap Alclad to restore stability to this part.
    • The gaps between the front and rear spat halves, particularly on the nose gear fairings, were a bit irregular so I took the time to fix them up with micro.
  • Finalized everything behind the baggage bulkhead so that I can rivet on the final top skin.
  • All sorts of miscellaneous jobs, too numerous to list. These seem to be never-ending.

I’ve come to realize that if I don’t move everything to the hangar soon, it may become too wet and muddy around the workshop over the winter months to easily do the move. The mud around here is amazing – it can be like grease without too much rain at all. My current activities are aimed around doing this move in the coming weeks.

  • aaa_bottom_skins
    Riveting bottom wing skins
  • f61c
    Improvised bucking bar for rear spar rivets under wing walk area
  • aaa_wing_skins
    Inevitable side effect of riveting bottom wing skins
  • f61d
    Aligning the main leg fairings
  • f61e
    Work on the "split" bottom leg fairings
  • f61f
    Working on nose wheel fairing
  • f61m
    Fairing support bracket modified for Matco brakes
  • f61l
    Fairing support bracket modified for Matco brakes
  • f61k
    Right main fairings
  • f61i
    Left main wheel fairings
  • f61h
    Split leg fairing, left side
  • f61g
    Split leg fairing, right side
  • f61j
    Nose wheel, leg fairings
  • aaa_painting_spats
    Painting insides of spats etc.
  • f61a
    Centre console fitted
  • g1i
    Overhead panels in place

RV-14 ADAHRS Bracket [3.0 hours]

I originally mounted a bracket in the empennage for the Garmin magnetometer. Years ago. Then I switched to Dynon avionics, so I was going to have to make a new bracket for the Dynon ADAHRS, and wasn’t looking forward to crawling into the tailcone to install it.

Then I came across the Van’s RV-14 ADAHRS bracket, which looks like a clever design. It goes in the left wing, inside the inner access cover. The RV-14 wings are the same as the RV-10 wings, just shorter. I looked at the drawings and the dihedral appears to be the same, so I ordered the following parts from Van’s:


With these in hand, I prepared an installation for the left RV-10 wing using the following procedure:

  1. Prepare the parts using the RV-14 instructions on page 20-03 of the RV-14 wing manual.
  2. When fluting the W-00012C parts, do not simply hand hold the part and hit it with the fluting pliers. Mark the distance in common with the W-00012B parts, and securely clamp the W-00012C between a block of wood and the workbench so that this area remains flat. Then, use the fluting pliers only on the exposed part – see the picture.
  3. Cleco the parts together. Position on the LH inner bottom wing skin, and verify you have the correct orientation.
  4. Draw a line between the center of the two wing rib holes, these are the fourth holes down from the J strut. Reposition the bracket to be aligned with the center of the access cover, and match drill/cleco the end two holes in the Z bracket through the bottom skin. I used a #42 drill bit, and once all holes were drilled, match drilled with a #40 reamer.
  5. Remove the W-00012A bracket, drill the remaining holes from the Z bracket through the bottom skin.
  6. Remove the Z bracket, de-burr the holes just drilled in the Z bracket and the skin. Dimple the holes for flush rivets, and reassemble all parts.
  7. Keeping the bracket aligned so it is not “twisted”, match drill #40 from the W-00012A bracket into the J strut, cleco’ing as you drill each hole. Enlarge all holes to #30. Disassemble and de-burr.

That’s it. I’m not going to assemble the bracket until I prime the parts, but with the pieces cleco’d together I checked the position and clearances. You can see from the photos that there is plenty of room for the cables and air connections. The OAT sensors can be mounted in the bottom wing skin, near the access cover – see the RV-14 instructions for a typical hole position (I haven’t drilled these yet).

The RV-14 instructions call for countersinking the W-00012C retaining strips for AN426AD4 rivets. The strips are too thin for this, the countersink would need to continue on into the W-00012B parts. I see no purpose for using countersink rivets here, so I’m going to use regular AN470 rivets instead, obviating the need for countersinking the parts.

I have to mount the OAT sensors, make up a wiring harness with tie downs and re-route the air lines. I’ll do these jobs once I’m ready to close out the wings.

  • f46a
    RV-14 ADAHRS bracket parts and instructions
  • f46b
    Fluting the retainer strips
  • f46c
    RV-14 ADAHRS bracket parts prepared/deburred
  • f46d
    Drilling the bottom wing skin
  • f46e
    Deburring holes added to the bottom wing skin
  • f46f
    Dimpled new skin, Z bracket holes
  • f46g
    Match drilled holes into J strut
  • f46h
    Checking Dynon ADAHRS fit
  • f46i
    Bracket in place, old air line routing will have to change.
  • f46j
    Bracket cleco'd inside bottom wing skin, all fits OK
  • f46k
    Looking up through access cover. Plenty of clearance all around.


Finished right flap trailing edge [3.5 hours]

I’ve kept the straight edge I match drilled the right flap leading edge into clamped to the edge of one of the workbenches, to remind me to finish the flap. Today was the day to do that. Same process I’ve described previously – bind the trailing edge with double sided construction tape, then keep drilling 13mm holes out of the straight edge, using a squeezer through the holes to set rivets. Once again it worked a treat, and the right flap trailing edge is perfectly straight. This is also the last trailing edge I have to do – that’s all seven now done and they’re all dead straight. That leaves bottom skins, wiring and fairings for the wings – which I’m putting off for a while so I can make progress on the fuselage.

  • w60a
    Right flap, trailing edge wedge, scuffed and cleaned ready for tape
  • w60b
    Wedges taped in, cleco'd down to previously match drilled straight edge
  • w60c
    After second round of riveting, every second hole done.
  • w60d
    Finished trailing edge - dead straight - and scrap straight edge

Right flap construction [28.5 hours]

The right flap is now done, except for riveting the trailing edge. This is the last control surface assembly, and it seemed a bit odd to realize after I’d countersunk the trailing edge wedge that I wouldn’t need the drill jig any more. Assembly was straightforward, except for some reason about half a dozen holes on one end of the trailing edge were offset slightly, just enough for cleco’s to not fit. Match drilling through these holes worked fine without any enlargement so they weren’t that far off.

A long time ago on the empennage I messed up a VA-140 trailing edge wedge, and stole one from the wing kit. That left me one short. An RV-7 builder in Melbourne kindly obtained one for me along with his empennage kit. I finally unpacked it last week and used it for this flap – so thanks Joe!

Still plenty left to do on the wings, but I have some primer expiring towards the end of the year and a few months of mild weather coming up so I’m going to make a start on the fuselage in the coming weeks.

  • w57a
    Skins cleco'd onto right flap skeleton
  • w57b
    Replacement VA-140 - thanks Joe!
  • w57c
    Match drilling right flap
  • w57d
    Riveting right flap skeleton
  • w57e
    Ready to rivet top skins
  • w57f
    Ready to rivet top skins
  • w57g
    Ready to install bottom skin for trailing edge match drilling
  • w57h
    Match drilling trailing edge
  • w57i
    Match drilling trailing edge
  • w57j
    Finished match drilling right flap trailing edge
  • w57k
    Trailing edge after dimpling, edge relief visible on both top skin and bottom of nose skin
  • w57l
    Straight edge has #40 holes match drilled from trailing edge
  • w57m
    Countersunk trailing edge wedges, the last use of my awesome wedge drill jig
  • w57n
    Riveted bottom skins to main spar

Right flap started after (yet another) break [8.5 hours]

I’ve had yet another break from building, but this time it was for a good reason – a flying trip! We went on Aussie Flyaway’s latest air safari “across the top”. This is the second time we’ve gone on one of Tony and Angela’s organised air safaris. This time there were just five aircraft, shared by a group of thirteen. It was a fantastic trip, covering a bit over 4,500 nm in two weeks. We were originally going to rent a 182 out of Redcliffe, but then changed over to going in a friend’s Cessna Corvalis. Apart from a diversion to Birdsville (where we got stuck for two days) due to thunderstorms while enroute to Alice Springs, the weather was fantastic and the trip went off without a hitch. More incentive to get on with the build!

The last major assembly yet to do for the wings is the right flap. I started this over the past few days, and have it up to the point where all the ribs, spar and flap brackets are de-burred and assembled into the right flap skeleton. Next step is to match drill and de-burr the skins.

  • across_the_top
    Actual flight path for the trip, which originated and finished in Mildura
  • w55a
    Right flap skeleton assembled


SERVICE BULLETIN SB 16-03-28 adventures [5.5 hours]

Carrying on from the previous post on this matter – here – I completed the replacement of the left wing aileron bracket, again with no dramas. I then did a trial fit of the left aileron, and immediately ran into problems. Big problems, in fact.

The new bracket is much “wider” on the base than the old bracket, adding 1/8″ each side of the main bracket structure, due to the use of 1/8″ angle for mounting to the rear wing spar. The AN470AD4 rivet manufactured heads, when added to this 1/8″, remove all clearance previously available for the aileron to swing freely, and so the aileron with the standard spacer/washer setup (per Figure 1 on page 21-10 of the construction drawings) now rubs across the top of these rivet heads – see the attached pictures.

I contacted Van’s, and they suggesting changing the washer/spacer arrangement to move the aileron outboard. I tried this, but with only 3/32″ between the outboard edge of the aileron and the manufactured heads of the rivets on the outboard bracket, there just isn’t enough room to solve the problem this way and still maintain reasonable spacing between the sides of the aileron nose and the rivet heads.

So, I contacted Van’s again, and asked them if it would be acceptable to replace two of the existing AN470AD4 rivets with AN426AD4 rivets. Van’s response was as follows:

Using the 426 rivets should be no problem if that is what works best for you there. The bracket is more than thick enough to be countersunk and the rivet strength is the same.

The only problem then is how to actually do it, since the brackets were already installed on the wings and these are very long rivets. I used a long 3/32″ drill to carefully drill out the rivets,  and a 3/32″ punch to drive them out. Countersinking was easy with a right angle drive bit. I didn’t actually have any AN426AD4 rivets that were long enough, I had some -9’s but these were too short. I went looking in the hardware of the slow build fuselage kit, and found a bag of ten AN426AD4-16 rivets, so I stole a couple of these and used a rivet cutter to trim them to the correct length. My guess is the right size would be either AN426AD4-10 or AN426AD4-11. The new rivets were easy to set with a pneumatic squeezer and 4 inch yoke.

The aileron now swings freely without any problems. The pictures show the standard spacer/washer arrangement. When it comes time to do the final rigging, I expect I’ll shift the aileron by one thin washer width, to even up the clearance gaps on the inboard and outboard sides.

Now I have to go back and do the same change to the right wing bracket. It would have been sooooo much easier to have installed AN426AD4 rivets in these positions in the first place.

August 11 update: I did the same with the right aileron bracket, no issues and quite a bit faster the second time around. I’ve added some pictures covering this change.

  • w54a
    Trial fit of left aileron, after replacement of aileron bracket
  • w54b
    Inside web of aileron rubs across rivets on the new bracket
  • w54c
    Aileron alignment is OK, gap is 0.17" - a bit lower than the nominal 0.25"
  • w54d
    Preparing to drill out AN470AD4 rivets. Damage on rivet heads is from aileron scraping
  • w54e
    Rivets punched out
  • w54f
    Old rivet shanks after drilling and driving out
  • w54g
    Set up for countersinking holes
  • w54h
    Holes countersunk
  • w54i
    Set up for squeezing AN426AD4 rivets
  • w54j
    AN426AD4 rivets in place
  • w54k
    Aileron now swings freely. Probably needs one more 416L washer spacing to balance up inboard/outboard gaps.
  • w54l
    Another view of replaced rivets
  • w54m
    Old bracket held in front, showing how the new bracket has 1/8" less clearance inboard of aileron
  • w54n
    Now I have to fix up the bracket on the right wing...
  • w54o
    Rivets drilled and driven out of right aileron bracket
  • w54p
    Rivets drilled and driven out of right aileron bracket
  • w54q
    One perfect drillout, one that impinged a bit on the hole but OK
  • w54r
    New rivets in place
  • w54s
    Rivets set
  • w54t
    Right wing aileron hung
  • w54u
    Same fit as left, needs to be shifted outboard slightly but OK for now.

Right wing leading edges [11.5 hours]

Time to deal with the right wing fuel tanks. Although it isn’t very pretty, I like to prime at least the surfaces that overlap others, such as along the rivet line to the main spar. I can’t allow any primer to get on the pro-seal though, so I taped off everything except those parts I wanted primer on.

With the tanks primed, I fished out the fuel lines I already fabricated, and the emergency transfer pump. As with the left wing, I joined the two leading edge sections (main tanks, and outboard leading edge / aux tanks) together on the bench, and installed the fuel lines etc. I then pressure tested the entire assembly, which includes the fuel lines and fittings around the emergency transfer pump. Each tank had previously been pressure tested, so I wasn’t expecting any problems. There weren’t any.

I then joined the leading edge assembly up with the wing box section. Just like the left wing, these all went together really well – which says something for the precision of the Van’s kit. I modified the right side of the wing rack to take the new assembly, once it is in the wing rack I can finish the riveting. I still have to put the left wing on the bench to replace the aileron bracket.

  • w53a
    Fuel tanks after a bit of priming
  • w53b
    Right wing centre bay, note access panel on bottom of wing.
  • w53c
    Another view of right wing centre bay
  • w53d
    Right wing fuel tanks, outboard leading edge
  • w53e
    Main fuel tank joined up with outboard leading edge. Fuel lines and emergency transfer pump ready for assembly.
  • w53f
    RIght wing leading edge sections joined up
  • w53g
    Fuel lines and emergency transfer pump in place (wing is upside down)
  • w53h
    Pressure testing both tanks and fuel lines as an assembly
  • w53i
    Manometer level stays constant with a stable temperature and barometric pressure
  • w53j
    Ready to join leading edge assembly with wing box section
  • w53k
    Leading edge and box section all joined up
  • w53l
    Preparing wing stand for the new right wing assembly
  • w53m
    Right wing assembly ready to go back into wing stand
  • w53n
    Riveting bottom side
  • w53o
    Bottom side riveting complete

Replacing aileron brackets – SB16-03-28 [4.0 hours]

A couple of months ago, just after I’d finished riveting the flap and aileron gap fairings onto the wing box sections, Van’s released a service bulletin which applied to all aircraft models. In the case of the RV-10, there has been no reported cases of cracks in the inner aileron support bracket, and there is no requirement to replace the existing bracket on “fully completed wings” if no cracks are found. My wings aren’t fully completed yet – the bottom skins are still off. This means I have much better access to replace the aileron brackets. I thought about this for quite a while, and ordered the replacement bracket kit. After the parts arrived, I thought about it some more, and elected to go ahead with the replacement because:

  • I felt comfortable doing the drillouts without making a mess of the spars
  • My wings are still open on the bottom, making the job a lot easier
  • Van’s themselves are replacing the brackets on all new quickbuild shipments
  • The new brackets are substantially more robust than the old brackets, indicating a desire on the part of the designers to greatly strengthen this part.
  • By doing this I avoid having to periodically inspect the area in accordance with the service bulletin

I separated all the parts, match drilled and de-burred them, and primed. I had ordered new bearings along with the brackets themselves. Assembly of the parts was simple.

Then it came time to pucker up, cut the aileron gap fairing, and drill out the old bracket. I did this on the right wing box section, because it doesn’t yet have the leading edge assemblies in place and was easier to put up on the bench. I drilled out two rivets to trim the aileron gap fairing properly, plus the eight rivets holding the old aileron bracket in place. Taking a lot of care with this, I was able to punch out all of the rivets without causing any hole enlargement. I took a picture of the area after removing the old bracket, since I did such a good job of this, and found out that evening that I’d lost a whole series of pictures because the camera had an episode and corrupted its SD card. I was able to recover some pictures, but not the ones that counted.

I riveted the new bracket on, and everything looked good. Last job was to reinstall the two rivets I had removed from the aileron gap fairing. I then discovered that at least one of these should have been set before I had installed the aileron bracket. In the last picture, you’ll see that this rivet is sitting right up against the rear bracket stiffener. If I had set the rivet first, it would be OK. As things stand, if I try and buck this rivet I suspect it’ll just make a mess behind there. I’ve sent a picture Van’s and asked them if it is acceptable to install an MSP-42 pulled rivet in this location.

Apart from that problem, right wing all done, and I have the new bracket ready for installation on the left wing.

  • w51a
    Cutting W1013 parts
  • w51b
    Cut W-1013F,G parts
  • w51c
    Match drilling new aileron brackets
  • w51d
    New aileron bracket parts ready for priming
  • w51e
    Left aileron bracket ready for assembly
  • w51f
    Assembled left and right aileron brackets, ready for installation
  • w51g
    New right aileron bracket installed, except for rivet in modified gap fairing
  • w51h
    New right aileron installed
  • w51i
    Problem gap fairing rivet - should have been set before aileron bracket