Model Forum / Radio Controlled / Helicopters / July 2005

I was having trouble when refueling or carrying my heli with fuel making its
way into the muffler/fuel tank line and filling the muffler and sometimes
the bore with fuel.
I devised a device to stop this happening. It consists of an old ball link
ball inserted into a small length (3cm) of the black tubing people use in
their gardens for the sprinklers.The tube is around 5-6mm in diameter.I then
inserted a ball bearing into the tube (must be reasonably smaller than the
inside of the tube) so that it when it came into contact with the ball link
ball it rested in the recessed end of the ball link ball. I then screwed a
threaded joiner that you use to join the black tubing together into each end
of the tube.Because the end of the joiners are cut at an angle the ball
bearing doesnt seal against the joiner when it makes contact with it.
Points to watch are that the joiner doesnt jam the ball bearing against the
link when you screw it in and also that the ball bearing can roll freely
from end to end.
I then fitted the finished valve between the fuel tank and the muffler
making sure that the air flow was from the muffler to the tank and not
viceversa.
I added a "T" piece between the tank and the valve and attached a length of
fuel line to the "T" and fed this thru the heli to where my fill point was
located (mounted thru the canopy with a plug in the end)
I added another plug to the new fuel line so that it could be shutoff when
engine was running etc.

So now when I fill I just plug my fill line into the fuel line as usual and
unplug the "breather hose" to let the air escape from the tank.I replug both
lines when finished filling and theres no fuel in the motor/muffler at all.

Some body has probably already thought of this or something better I just
thought I would share what I had come up with.
Dennis