It is a feed on demand system. With the cline system your tank and lines are pressurized so that there is a constant
supply of fuel to the controller. The controller then passes fuel to the carburetor based on demand. Without the cline
system, you are relying on mostly muffler pressure to supply fuel when the plane is vertical, which sometimes is not
enough with giant glow engines...especially when performing hovers at 1/4 to 1/3 throttle. Also, before I had the
cline system, I found myself always tweeking the high end with changes in temperature.

Go to http://www.billsroom.com/pcfs/ and click on the PCFS link. The regulator is $60.00 which is a small price to pay
when you consider how much it would cost to replace a plane if it dies in a hover.

There is a lot of information on RC universe regarding the Cline system. Do a Cline regulator search and you will see
more information on this device than you can digest.

Greg