Fuselage Join, Luggage Floor, Parachute Box

I’ve been busily working away on the fuselage over the last 2 weeks, and have built up a backlog of info and photos; it will take me a few days to catch up my blog / build record! This slightly long blog post covers the following topics:

  • Center to rear fuselage join (Fuselage KAI page E26)
  • Rear Seat Modification (Fuselage KAI pages E41-E43)
  • Long Elevator Pushrod (Finishing KAI page 4)
  • Luggage Floor install (Fuselage KAI page D10)
  • Parachute box install (Fuselage KAI page D14-D16)

Build Manual Reference: TSi Fuselage KAI Page E26

After addressing the interference problem between the torque tube and rudder cable conduit fittings, I continued with joining the center and rear fuselage. This involved riveting together ribs, longerons, skins, and channels at the interface between the two assemblies, and there were definitely a few places where it was hard to work due to limited access.

I did run into one problem during the join – in order to join the longerons beneath the rear elevator torque tube, I had to uninstall the rear seat modification I already riveted together, guess I got ahead of myself… oops! I had to drill out about two dozen rivets and then clean up the chips, but on a positive note, I was able to better install the upright angles/channels that are part of the rear seat modification.

There are longerons that need to be riveted together underneath the torque tube – impossible to access due to the rear seat channel I already installed
Closer view of the longeron rivet holes – need to uninstall the channel marked with an X
Rivets installed. Still difficult to get to, and for the rear-most one, I had to install it from the other side — just no way to squeeze the rivet puller into this space

Build Manual Reference: TSi Fuselage KAI Page E41. E42, E43

The next photo shows what I did differently with the rear seat modification. If you install the “Seat Base Extension Channel” part CF-CHL-045-C-C- as per page D41, you won’t be able to rivet the angle and channels into the floor ribs on page D42. It’s not really shown on page D42, and I’m not sure how critical it is for these to be riveted to the floor ribs. But, these angles (CF-ANG-013-R/L) and the channel
(CF-CHL-044-C-C) have pre-drilled holes that suggest they should be riveted to the floor ribs, so I took the time to match-drill the holes, like shown in the red circled area in the photo. I temporarily attached the Seat Block Channel (CF-ANG-012-C-C-) as shown on page D43 to help line up the channels and angles. They seemed much more secure after I riveted everything back together.

Installing the rear seat modification – there are holes that need to be drilled into the floor rib to support the channel and angles

Build Manual Reference: Sling4/TSi Finishing Kit Construction Manual Page 4

After the join was complete, I installed the pushrod through the rear fuselage for the elevator. I don’t think I absolutely have to install it at this point in the build, but it appears this task would be harder to do later once the rear seat modification is installed, which blocks access to the torque tube that the pushrod attaches to.

I couldn’t get the push-pull tube to fit through the bushing that’s about half-way down the rear fuselage – the rivet heads protruded out just a little too much. I didn’t want to scrape up the bushing, so I drilled out the rivets and removed the bearing assembly. These use stronger SS rivets, but luckily I already have replacements from doing my torque tube mod.

Bushing is just a little too tight to push the tube through due to rivet heads
Removed the bearing assembly from the end of the long push-pull tube

Build Manual Reference: TSi Fuselage KAI Page D10

So that I could install the luggage floor, I had to finish cabling routing through the floor beneath the luggage floor… and I continued all the way to the tail. I decided to use split tubing for the wire bundle that carries power and signals to the avionics and lights in the tail. I’m assuming the luggage floor will be very difficult to remove after it’s installed and covered with carpet; in theory, the tubing should make it at least possible to pull new wires through that section, if I have to in the future. I’m working on a YouTube video showing the wire routing through the rear fuselage.

Area under the luggage floor
Another view of cable routing as it passes from the center to rear fuselage

Next, I installed the luggage floor. I assembled the floor a while ago, but left off a small bracket that goes on the front corners. This part RF-ANG-019-X-C-0 is not shown in the build manual, and it’s confusingly packaged in the Luggage Door Support subkit… you’d already be well past the point of being able to install these brackets by the time you install the luggage door. I installed these to the luggage floor, but I think these would have been easier to install to the rib of the fuselage first, and then rivet the floor to the brackets.

Don’t forget these Luggage floor supports RF-ANG-019-X-C-0
Luggage floor supports should be installed on the front corners of the luggage floor

Because I am installing the parachute, there is a extra channel below the floor of the luggage that joins with the side skins. The skins don’t have these holes pre-drilled, so I had to manually match-drill the holes.. which was not easy, given the limited access. I marked the holes using a sharpie, removed the floor and then drilled the holes.

Floor temporarily clecoed in place
Three holes that have to be match-drilled for the luggage floor support channel
View of the three holes from the other side
Glad to have the luggage floor installed!

Build Manual Reference: TSi Fuselage KAI Page D14, D15, D16

For the parachute box, I had to follow the TSi build manual because my parachute box parts are a newer revision than what was used in the Sling 4. I thought I would be clever and use flush rivets on the side of the skins that face into the luggage area, so that there wouldn’t be any lumps in the carpet covering, and I started putting in rivets this way. Halfway through doing this, the voice in my head told me something wasn’t right, so I consulted the build manual again. On page D15, there is a note that says “Rivets to be installed in the direction of the arrows”, but the arrows point both ways, which is not helpful. There are a few actual pictures of the parachute box on pages D23-D24, which I examined very closely. From those pictures, I determined is that these rivets actually need to be installed so that the smooth side is inside the parachute box. I’m sure this is done to ensure that the parachute doesn’t catch on any protruding rivets as it deploys. So, I had to drill out the handful of flush rivets I had installed, flatten out the dimples, and then re-install rivets the correct way.

Rivets installed incorrectly!
Rivets installed properly, leaving the inside of this compartment as smooth as possible
Parachute box installed

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