Chapter 22 – What the Duct!

I started out today pulling off the peel ply from the aft side duct piece that will be joined to the forward side to make up the middle duct assembly, or “plenum,” in the pilot seat area. After removing the foam form and cleaning it up, I then taped the 2 midpoint duct pieces into place in the fuselage.

I then laid up 1 ply of BID over the exposed joint of the 2 halves.  I then peel plied the layup.

I made up a bit too much epoxy so when I finished the layup above I quickly shaped a piece of urethane foam and taped it up on the first duct piece coming forward from the pilot seat back.  I then laid up 2 plies of “trash” BID over the taped foam “duct bump.” This raised protrusion will be the entry point for the #3 valve control cable, which will run through the duct and control the valve internally.

A couple of hours later I pulled the bump layup off the duct, removed the tape and pulled the foam form & tape out.  I then trimmed the glass and set the control cable entry bump back onto the duct.

A head-on shot of the control cable entry bump set on the duct.

I then worked on the configuration of the pilot seat initial thigh support wedge that also serves as a cross-cabin air duct.

Since I needed to increase the top surface angle, with the front edge coming up, for a better intersect with the actual thigh support plate, I cut and shaped a 1/4″ thick foam bottom edge spacer.  This took some trial and error to dial in due to the curves in the fuselage floor/seat pan.  I also needed to finalize my glassing sequence and layup schedule, but it was getting late so I left it for later.

I did however layup the final BID tape joining the front & aft pieces of the PIC seat area duct “plenum” together.  I then peel plied it.

A few hours later, I pulled the peel ply off the second and final ply of BID joining the front & aft pieces of the PIC seat area duct “plenum”.

Of course then I had to mock it up to check it out.  Fits like a glove and I think it will work out perfectly.  I do have some more glassing to do on this component though since I need to make an exit duct on the inboard side that feeds air into the pilot seat thigh support initial wedge/duct.

Tomorrow I’ll continue to finalize this PIC area ductwork and initial thigh support structure, but I’d also like to finalize valve #3 on the GIB area air ductwork.

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