Closing in on final assembly, I disassembled the understructure and started on countersinking and dimpling where necessary. I had already previously countersunk a number of holes called for in this section following the hints on the rv10 wiki, so I was able to focus on only the parts that were not yet assembled.
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| Countersinking the fuse channels for a dimpled skin |
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| Lower fuse channels and clips ready for priming |
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| Forward fuselage bulkheads and ribs dimpled and ready for priming |
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| Upper fuse channels countersunk and deburred along with gussets and clips |
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| Two holes on the F-01042 bulkhead side channel that attach to the F-1042E gusset countersunk on the aft side for a flush rivet |
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| Hole that attaches the dimpled tab on the F-01088 fwd fuselage rib to the F-01042 bulhead side channel was also countersunk |
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| Additional hole that was drilled into the F-1018 outboard rear seat rib was dimpled using the tight fit dimpling set |
I also trimmed the ends of the F-1013 fwd fuse longerons as specified in the plans, and continued with countersinking the longeron skin holes and the mid cabin decks.
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| Fwd fuse longerons marked for trimming. I trimmed the ends off with a hacksaw and deburred using files and the 3M wheel |
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| Mid cabin deck holes being countersunk for flush rivets. Flange holes were countersunk by hand because there is no space to fit a countersink cage |
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| Deck holes nearest the flanges were also countersunk manually due to space issues |
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| Remaining deck holes were easily and quickly countersunk using the countersink cage |
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| Mid cabin decks ready for priming |
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| Longeron skin holes were countersunk to accommodate the dimpled skin |
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| All longeron skin holes countersunk |
One final step before priming involved drilling the rudder pedal attachment holes into the fwd fuse longerons. I had previously elected to do this with the longerons removed from the understructure so that I could better align the provided rudder pedal drill jig along the longeron edge.
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| Longeron clamped to workbench, with the rudder pedal attachment holes being drilled using a #13 drill bit followed by a #12 reamer. Holes were clecoed as each one was drilled |
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| Rudder pedal attachment holes drilled, and longerons ready for priming |
Next, I primed all of the understructure parts and set them aside to finish dimpling and deburring the skins.
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| Fuselage understructure parts cleaned and ready to prime |
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| Priming did not take long, and while these were curing I continued working on the skins |
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| Countersinking the skin holes that attach the vent doubler for flush rivets |
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| Right skin vent holes countersunk |
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| Left skin vent holes countersunk |
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| Vent doors countersunk for flush rivets |
I then dimpled the #40 holes in the skin, leaving several undimpled as outlined in the plans. There were also a few #30 holes that had to be dimpled for CS4-4 blind rivets.
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| Dimpling skin holes using the DRDT-2. Holes along the edges of the skin were dimpled using the pneumatic squeezer |
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| #30 holes dimpled for a CS4-4 rivet. Remaining #30 holes in the skins were left undimpled |
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| Fwd fuse skin holes dimpled |
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| #30 holes marked for no dimpling |
The final step before priming the fuse side skins involved cutting out the baggage door panel from the left aft skin. This was easily done using a tight fit hacksaw, after which I was able to clean up the edges using files and a small deburring wheel
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| Carefully cutting each tab using the hacksaw to ensure I don't damage the skin edges |
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| Baggage panel cut out with only filing and deburring remaining |
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| After deburring, the exterior baggage door panel which I will work on later, fits perfectly in the opening |
Next I riveted nutplates to the fwd cabin floor panels (a step which was not explicitly called out, but did appear in a diagram in section 28), and also to the upper fuse channels which needs to be done prior to riveting.
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| Nutplates installed in the fwd cabin floor panels |
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| These nutplates will later be used to attach an access/inspection cover |
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| Nutplates attached to upper fuse channels |
Finally, I got around to priming the fuse side skins. In preparing the fwd side skins, I masked off the section around the NACA vent opening, where the NACA vent flange will attach to the skin. I did not want this to be primed in order to get better adhesion to the skin surface.
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| A cardboard template worked well to mask off the shape of the NACA vent flange that will later be bonded to the skin |
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| Fwd fuse side skins primed |
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| Right aft fuse side skin primed |
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| Left aft fuse side skin primed |
Primer used: ~390g + 35g distilled water
Priming Time Taken: 7.8 hours
Fuse Side Skins Time Taken: 15.8 hours
Dates: September 1 2025 - September 13 2025
Fuse Side Skins Total Time: 64.5 hours
RV-10 Build Total Time: 1151.0 hours
Priming Total Time: 142.6 hours (not included in build time totals)
