Fuel line for glow engines is made of silicone
and is very flexible. It comes in four sizes that I
Used for 1/2A to .10 engines.
.15 to .60 engines.
This tubing is also called Large,
but there is an obvious difference in size. It is used for fueling pumps.
If you acquire new planes on a regular basis,
then it is more economical to buy a 25 yard roll of fuel line rather than three
Before you purchase a full roll, make sure you
buy a shorter length to find out if you like it. Fuel line varies a lot
between manufacturers and some is better than others. I have never had "bad"
fuel line, but I have had some that was very difficult to remove from fittings or
tore when removing it.
Fuel line does not need to be extremely tight on
fittings. It just needs to be tight enough to seal and to stay in place under normal operating circumstances.
Before installing the fuel line, be sure to
deburr all fitting on the fuel tank because silicone does cut easily.
Also, be sure to sand fuel line exits in the firewall so that vibration from the
engine does not cause the line to abrade.
I also radius the fuel line exit
holes on the front and back of the firewall using a counter sink so there are no
sharp edges. Seal the exits with epoxy or polyurethane before fuel
proofing the entire firewall. These two coats will make the exit nice and
smooth assuming you sanded the holes smooth in the first place.
I normally cut each piece several inches longer
than needed. There are two reasons for this. First, it makes it
easier to fish the lines through the firewall. Secondly, I would rather have
the line too long than too short and have to pull the tank back out to put on
Ensure that the lines are not kinked and have
large radius bends. I have never had an engine that couldn't draw fuel
because the line was too long. Larger bends will help prevent kinking as
well as give you extra length to make refueling easier.