RE: Assembly of Tettra tank
The Bubbleless type tetra comes with the internal bladder already inside the tan and the mouth of the bladder comes out the lip of the hard tank shell opening and folded back over this lip.
The soft rubber plug has a short aluminim pipe pushed in one hole only, this to protrude to the center of the tank inside it should have a short piece of fuel tube on the inside end to prevent rupturing the bladder.
This plug is inserted in the outlet and the outside of the plug goes around the outside of the plug lip. This now has the clampring and bolt clamped aroun the whole thing to hole everything secure. There is a small retangular flat steel plate that is bent into a curve and slipped under the the clamp ring at the bolt to prevent crimping the soft rubber plug material.
This single outlet in the plug goes directly to the carb and is also where the tank is filled from. Muffler pressure goes to the fitting in the lower right hand side front of the hard shell of the tank.
Bubbless tanks are best filled with a large syringe with the proper amont of fuel in the syringe. Then attach fuel feed line held vertical and the plunger is pulled out more to remove all air in the tank before pushing the fuel into the tank.
Bubbless tanks should not be foam mounted (there is no need) do not use a clunk on that internal pickup tube. They will have fuel delivery characteristics far superior to conventional muffler pressure systems and can be mounted in most cases on the aircraft CG.
John