Ch. 6 - Fuselage assembly - Part 15

Attaching the fuselage bottom (4.0 hrs)  

Today I joined the last major fuselage subassembly to the rest of the structure. It has been a long time coming, but the fuselage now resembles its final configuration. While it is still not strong enough to support any “foot traffic” yet, I am getting close to getting it done. With its outer skin is in place, it will have the much sought after structural rigidity, but for the time being, I will have to tread lightly. 

With my daughter’s help I sat the fuselage upside down on the sawhorses. This was necessary because some of the work needed to be done from inside the fuselage, as you’ll see.

  

Ready for "major surgery"

The first task of the day was taking care of old business. If you recall, last time I ended up cutting the flap of bid that extended past the edge of the rear seat floor, because I ran out of time. So, I prepared a 2 layer BID tape 4 x 20.5 inches (10 x 52 cm), attached it to the back of the rear seat, and peel-plied it.

BID flap attached to the back of the rear seat

Peel-ply in place

I spread flox on the longerons and bulkheads, and placed the fuselage bottom back on the fuselage.

Flox on longerons and bulkheads (except on rear seat).

Next, I put any heavy object I could find on top, and cleaned up the overflowing flox both inside, and outside of the fuselage.

Yes, those two tanks are full of gasoline.

Front-seat to floor

Instrument panel to floor (viewed from the back).

Instrument panel to floor (viewed from the front).

While I was at it, I added a bead of flox behind the “front seat to floor” juncture, per plans. All the bulkheads will receive the typical corner tape, but not the back of the front seat. I suspect the angle might be too acute to seat the BID tape properly anyway, furthermore the strands of fiberglass would not be able to transfer loads appropriately while bent to such a degree (remember the fibers are like little rubber bands, strong in tension, but weak in compression).

Flox bead in front-seat to floor juncture (viewed from the passenger compartment).

Meanwhile, the flap of BID I just attached to the rear seat was slowly curing. 

Semi-cured BID tape

A couple of hours later, it was tacky enough that I could attach it to the fuselage floor, and peel-ply it, without it falling back down.

BID tape epoxied and peel-plied to the floor, ahead of the rear seat

I’d say overall it was a pretty simple task. The only excitement of the day was coordinating three people in accurately placing the floor on the fuselage, as not to smear the bead of flox. 

Thank you Lou, Gina, and Cece.