I have used braided flexible fuel pipe as used on out board motors. Clamp rings were made from 8mm copper end feed fittings, These fit closely over the fuel pipe, one fitting can be cut to make three rings. to connect to the model make fittings with a rat tail, to insert into the fuel pipe. Slide a ring on the pipe over the inserted tail. To clamp the connection, Make a clamping tool. A piece of 1/4"MS, say 1" square, drill a hole in the centre, The same size as the ring next find a couple of dowel pins say 1/16dia, drill through the block for the dowels on one side of the block at 5/8" centres. finally saw to cut the block in half, each half having two dowel holes and half of the central hole. Assemble the clamp block over the pipe and close the joint between vice jaws. This should result in the ring being compressed into the fuel pipe and having a pair of ears at the sides.

Originally these were on a 3 1/2" black five  and are probably too heavy for the smaller model

Edited By hush on 30/08/2019 20:13:00

The yellow air line tube is very flexible and available in small diameters