Front Seat Base Mechanism

Sling 4 Fuselage Manual Page I3

In between working tasks for the rear seat belt mods, I’m also building up the front seats. I assembled the locking mechanisms that attach to the base of the seat pan. It’s a nifty mechanism that uses guide pins tethered by a steel cable and tensioned using compression springs. I made a small change to how the guide pin cable assembly attaches to the pull handle. I also finished the pull handle and front face of the assembly in powder coat black, to match the seat pans.

There are two white nylon (I think?) bushings that are supplied to act as a glide, held together by an AN3-6A bolt and lock nut. I assembled per the manual, but I couldn’t see how one would go about tightening said lock nut, since it’s inaccessible once assembled. The assembled glide is also too tall to fit in the space, so I’m guessing it would have to be ground down a bit. Instead, I created a new pair of parts: a lower bushing with an integral hex cutout to hold an M5 locknut, and a top bushing that has a small groove for the cable.

For 3D-printing this part, I just received a new filament: a carbon fiber-infused polycarbonate. Polycarbonate has great material properties, including strength, flexibility and high working temperature. This particular filament is rated to 100°C so I can easily use it without worrying about it deforming in a hot cockpit. So far, I’m really impressed with this filament!

Attaching the stopper pin assembly
Spring and guide pin mechanism
Bushings that are supplied to form a glide
The bushing assembly is too tall
Redesigned glide parts: lower bushing on the left, upper on the right
Glide assembled onto the pull handle with an M5 screw
Lock assembly complete and ready to be riveted to the seat pan

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