I use Viton for the clunk line and use a hard tube in the middle.
I've had an engine out on a 3d plane from a clunk line getting stuck in the front of the tank. That was after a blender though and I don't see a lot of jets doing blenders. I'm not sure the tube is required in a jet installation but I'm not sure it can hurt either. DAVEI'm interested to hear why you don't run the tube in the middle of the clunk line.
I can see no reason to use Tygon as a clunk line when Viton is available. I've literally got a tank that's 7 years old in one of my 3d planes and the Viton still seems to be just fine. Outside of the tank I get because it's so expensive.
Last edited by camss69; 03-13-2021 at 09:23 PM.