Coming back to section 29, I trimmed the corners of the firewall side angles to have room to drill and later rivet the side channels:
Corner of the firewall side angle to trim off
Trimmed firewall side angle
Hole that can be reached with the trimmed firewall side angle
Drilling the hole that requires firewall side-angle trimming
Checking for rivet set clearance against the trimmed firewall side angle
I then started deburring and machine-countersinking all the parts - there were a lot of parts, and that took over 20 hours of work in itself:
Deburred and machine-countersunk forward channels
Machine-countersunk bulkhead side channel
Machine-countersunk longerons
The only dimpling I did before primer was that around the baggage door opening, so that I could remove and deburr that area without the later dimpling deforming the skin:
Baggage door around which dimpling needs to be done before primer
I haven't posted in quite a while because my NAS (where I keep all my building videos and my Final Cut library) stopped working, and it took me a while to get a new one and set it up:
New NAS, where I keep (among other things) all the videos I post here!
With that resolved, I'll be making a batch of posts with everything we did in the last couple of months.
I jumped ahead to section 31 so that I could match-drill the top skins to the upper fuselage side channels and machine-countersink those before priming or riveting the side skins, to avoid interference.
This section starts with cutting and fabricating a few different angles/spacers:
Fabricated angles and spacer for the subpanel
We then had to bent the lower part of the panel:
Bending the bottom flange of the subpanel center section
We put it all together and final-drilled all the holes:
Final-drilled subpanel
Subpanel clecoed in place
Subpanel and top skin clecoed in place
The hand hold doublers require some forming to lay flat against the top skin:
Forming the hand-hold doublers onto the curved top skin
For the panel support angle, I used a center line on the spacer to keep it centered, then match-drilled the holes:
Aligned centerline on the panel support angle spacer, ready to match-drill
Match-drilled panel support angle
These steps were more than sufficient to be able to machine-countersink the upper fuselage channels, so I stopped at that - I'll probably get back to it much later when I work on the panel.
To get the longeron lines to align with the holes, I had to deburr/trim the top edge a bit, since it fits underneath the mid-cabin deck:
Mid-fuselage skin top edge, flush against the mid-cabin deck
With this, I match-drilled the skins to the longerons:
Match-drilled right forward fuselage longeron
Match-drilled left forward fuselage longeron
I then clecoed the forward side parts in place, including the forward side skins, and final-drilled/match-drilled all the holes:
Forward fuselage side parts in place (except for the skin)
Forward side skin, match-drilled to the understructure
All forward fuselage side parts in place
Upper channel match-drilled into steel firewall support bracket
While drilling the firewall bulkhead, I had a small alignment problem - the longeron was slightly too long and pushing the flange forward, making the holes not align - so I had to do those later, after trimming the longeron:
Misaligned holes on the firewall bulkhead flange
Longeron pushing the firewall bulkhead forward
Trimming the longeron forward tip
We also drilled the longerons to the gussets, which was slightly challenging since the pilot holes are in a tiny corner and "upside-down" - at least 3 hands required:
Match-drilling the longeron gusset holes
Longeron gusset match-drilled into longeron
Longeron gusset holes (very tough location to match-drill from below)
Another challenging (actually impossible without modifications) hole is the forward-most hole in the forward fuselage channels:
The right-most hole is impossible to drill or later rivet (upper fuselage channel)
Same impossible hole on the lower fuselage channel
For this one, apparently I will need to trim some of the firewall side angles for access - I wish I had realized this while still building the firewall.
I drilled all the other holes, which includes all the channel to firewall bracket holes:
Firewall bracket match-drilled from upper fuselage channel
as well as the floor to lower fuselage channel:
Floor panel match-drilled to lower fuselage channel
With almost all the drilling done, it's now time for a lot of deburring and countersinking, then primer and dimpling.
Time lapse:
Total fuselage side skin rivets: 0 Total fuselage side skin time: 60.4h
I twisted the ends of the longerons by the required 2 degrees:
Longeron end twist at exactly 2 degrees
I installed them back and started countersinking the mid-cabin decks - first the screw holes:
Countersunk mid-cabin deck screw holes
then the rivet holes on top:
Countersunk mid-cabin deck rivet holes
For the skin clamping blocks, I couldn't find hardwood 2x4s anywhere local, so I ordered them online (here) and got some very precisely-cut pieces by mail. I got one hard maple and one red oak since I wasn't familiar with working with either and wanted a second one in case I screwed up:
Maple and oak 2x4s I ordered
Just to be sure we had some idea what we were doing, we started by making the same cut on a 2x4 (which we can still use for the other skin, where a radius is required in the clamping block), before cutting the maple:
Cutting the hard maple at just the right angle
Clamping block (one from a regular 2x4, one from hard maple)
The cut was far from perfect, but likely good enough for the intended purpose of bending the skins.
Since the second clamping block needed a radius and could be done with a 2x4, we made the additional cut on that as well:
Modified clamping block made with regular 2x4
We then started the repetitive work of bending the bottom parts of the skins with those blocks, to make them fit the curve at the aft end of the fuselage:
Bent and clecoed mid-fuselage skin
Rinse, repeat for the forward skins, except that for these, the roll construction angles aren't attached with clecos, and we didn't have any single clamp strong enough to hold them in place while twisting, so we had to use several clamps and mount it backwards:
Clamps for bending the forward fuselage skins
Bending the forward fuselage skins
The result was also quite good:
Bent and clecoed forward fuselage skin
Fuselage skins clecoed in place
Fuselage skins clecoed in place
I then started final-drilling the holes, including those of the baggage floor angles:
Right-side baggage floor angle attached to skin
Left-side baggage floor angle attach to skin with shims
The forward sides of the mid-fuselage longerons are attached to the gussets, which I also match-drilled:
Gusset match-drilled into mid-fuselage longeron
Since we were doing wood work, I also used the excess tip from the 4' maple beam to make a couple of blocks for twisting the fuselage channels:
Fuselage channel with spacer blocks for twisting
Fuselage channel spacer block height
Twisted fuselage channel
On a completely unrelated part (done while I waited for the wood), I separated, partially deburred, clecoed and final-drilled the side vent parts:
Separated vent parts
Deburred and final-drilled vent parts
Still a ton to do for the fuselage sides, but I'm glad that the most-hated parts of bending, twisting, etc. are over. I'll likely only do anything else significant after I'm back from Airventure.
Time lapse:
Total fuselage side skin rivets: 0 Total fuselage side skin time: 44.2h
