Mid-fuselage ribs started

I started section 26, Mid Fuselage Ribs and Bottom Skins.

The first steps were to break apart some parts, then put together the inboard seat ribs and match-drill/final-drill its holes:

Inboard seat rib subassembly with the flap actuator and seatbelt attachment brackets

Putting those together with the flap actuator bracket yields the first tunnel part:

Inboard seat rib subassembly

Flap actuator bracket between inboard seat ribs

I still need to further modify the flap actuator brackets to accomodate the newer flap motor (which has built-in position sensing), as those are supposed to be offset forward and up. I'll only actually have those motors in 4+ weeks when they ship it though, so that'll have to wait a bit.

That, along with the outboard seat ribs, got clecoed and match-drilled to the aft center section bulkhead assembly:

Aft center section bulkhead clecoed to inboard and outboard seat ribs
Next came the rear seat ribs (between the rear spar and the fuselage bulkhead subassemblies), which were all clecoed then match-drilled together, along with the rear seat belt attachments:

Rear seat ribs clecoed in place

Rear seat belt attachment points

Finally, I added and match-drilled the baggage ribs and step mounting brackets, and this now is starting to look like a fuselage:

Full aft assembly including baggage ribs and step mounting brackets
I now have a huge pile of parts (including the mid-fuselage bulkhead parts) to deburr and prime before I start riveting. I'll only match-drill the bottom skin once those are in their final position to avoid the difference in thickness from accumulating.

Time lapse:


Total mid-fuselage ribs and bottom skins rivets: 0
Total mid-fuselage ribs and bottom skins time: 11.4h

Mid-fuselage bulkhead fabrication almost done

After a quick trip to Germany, made a lot of progress on the mid-fuse bulkheads this weekend.

I started with the aft center bulkhead, which has bars at its ends for added structure:

Aft center bulkhead support bars
They also have two hat stiffeners, which I had to trim back to allow access to buck rivets next to it:

Trimmed hat stiffeners
I put the whole thing together, and did a lot of drilling:

Aft center bulkhead parts
Finally, this spar receives a plastic wear strip on top, which had to be cut to size, drilled then match-drilled to the spar:

Wear strip
I also did something similar for the rear spar bulkhead. This is the spar which attached to the rear of the wings, but I forgot to take pictures while it was still clecoed together:

Rear spar bulkhead parts
 Last there was the rearmost fuselage bulkhead, which was pretty simple and mostly gets done in later sections:

Fuselage bulkhead
Finally, I did a lot of deburring and all the countersinking that was left on these parts.

I also started thinking about how to run wires, pressure lines, oxygen lines, etc. between the forward and aft sections of the plane. I haven't decided on final routes yet, but it's clear that I need at least one more hole for conduits where the center spar is, so I added those to both bulkheads:

Third hole added to forward center section bulkheads

Third hole added to aft center section bulkheads
I plan to add a doubler to those bulkheads just for safety, so I'll enlarge them after the doubler is also in place.

Time lapse:


Total mid-fuselage bulkheads time: 18.9h

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