Model Forum / Radio Controlled / Helicopters / October 2004

Just "uniflowed" the Raptor 50 fuel system, and What a difference! A
constant run all the way through the tank, AND header tank, without any sign
of leaning out! Also managed to lean the OS out three more clicks and did
THAT relesase some power.........Most impressed.

For those of you NOT familiar with the process, it involves re-plumbing the
fuel system. You need to buy or make a new main fuel "stopper" that pushes
into the tank. The difference is that this one has TWO tubes going in. One
you use as your conventional clunk for fuel supply, the other is also fitted
with a clunk, but THIS one takes the pressure line from the exhaust system.
The existing exhaust pressure nipple is blanked off for flying, and opened
for refueling, as Rick found out to his cost this afternoon when he filled
the exhaust with raw fuel by forgetting to unclamp the vent tube!

The technecalities are many, but because the exhaust pressure is entering
the fuel, not the gap ABOVE the fuel in the tank, the pressure remains more
or less constant  no matter what the level of fuel in the tank. And NO, the
exhaust does NOT create bubbles in the tank!

For more info go to:

http://www.fraserker.com/helilessons/index.htm

and on the navigation panel on the left look for the Heading "Heli Science",
and underneath that, "The Uniflow System".

WELL worth the effort