4
For More Information on Magnum engines, Please Visit Our Website at http://globalservices.globalhobby.com
✦
✦
✦
✦
✦
IMPORTANT
✦
✦
✦
✦
✦
Your XL RFS series engine is a ringed engine. A ringed
engine is designed differently from a typical ABC-designed engine that
you might be more familiar with; therefore, you will not feel much hesitation
as the piston moves through the top of the stroke. A ringed engine does
not have any taper in the sleeve. Ring tension is what seals the
combustion chamber. When the engine is brand new, it will not feel like it
has much compression. This is because the ring has not yet been seated
with the sleeve. After the engine has been broken in, compression will
increase. The break-in procedure will guide you through the steps
necessary to properly break in your new XL RFS series ringed engine.
Please follow the steps closely.
The break-in process allows the engine parts to perfectly fit each other and
properly protect each part from premature wear. The engine should be
broken in using a fuel that contains no more than 10% nitro methane and no
less than 18% Castor/synthetic blend lubricant. Fuel containing only
synthetic lubricants should not be used during the break-in procedure. For the
break-in procedure we recommend mounting the engine into the airplane it
will be used in. This way the muffler, fuel tank and throttle linkage can all be
tested in combination with the engine. If your airplane uses a cowling, it
should be removed during the break-in procedure.
❑
1) Turn the high speed needle valve out 2-1/2 turns from the fully
closed position.
❑
2) If you are using an electric starter to start the engine, follow the
procedure in the previous section. If you are starting the engine by hand,
follow that procedure in the previous section.
❑
3) Open the throttle barrel to approximately 1/4 throttle. Connect the
power to the glow plug. Start the engine using an electric starter or by hand.
If starting by hand you will need to vigorously flip the propeller through the
compression stroke several times before the engine will start.
❑
4) Once the engine starts, open the throttle barrel to about 1/2 throttle.
You may need to lean the high speed needle valve in about 1/4 turn to keep
the engine running at half throttle.
❑
5) After the engine has been running about 1 minute, remove the power
from the glow plug and slowly advance the throttle barrel to full throttle.
Adjust the high speed needle valve so that the engine is running very rich.
You should notice excessive white smoke coming from the exhaust. Let the
engine run for approximately 10 minutes then stop the engine.
❑
6) Let the engine cool for approximately 10 minutes then restart it. Set
the high speed needle valve mixture to a slightly leaner setting, about 1/4
turn more in. Let the engine run for about 5 minutes at this setting, then stop
the engine and let it cool for approximately 10 minutes.
❑
7) Repeat the procedure in step # 6, while leaning the needle valve slightly
more each time. In all, you should run the engine about a total of 45 minutes
of actual running time. After 45 minutes of run-time the engine is ready for
flight. Fly the airplane with the engine set as rich as possible, but with
adequate power to fly the airplane. After each flight, lean the mixture slightly.
Continue to do this for about 5 flights. At this point the engine should hold a
good setting on the high speed needle valve and you can begin to fine tune
the needle valve settings to increase performance.
BREAK-IN PROCEDURE
Now that your engine is broken in, you can set the high and low speed needle
valves for optimum performance.
Please jump to the top of the next column.
OPTIMIZING THE MIXTURE SETTINGS
✦
✦
✦
✦
✦
WARNING
✦
✦
✦
✦
✦
Be careful never to lean the engine out too much.
Remember that the lubricants for your engine are suspended in the fuel.
If you lean out the fuel mixture too much you will also be lowering the
amount of lubricant entering your engine. Less lubricant means more
chance of your engine overheating and possible engine failure.
Setting the High Speed Needle Valve
❑
1) Start the engine and remove the power from the glow plug. Allow
the engine to warm up for about 30 seconds.
❑
2) After the engine has warmed up, slowly lean the high speed mixture
until the engine reaches peak rpm. After reaching peak rpm, richen the
mixture slightly until an audible drop in rpm is heard. If you are using a
tachometer this should be between a 200 - 300 rpm drop.
❑
3) With the engine running at full power, carefully lift the nose of the
airplane about 45º into the air. The mixture should not become too lean, but
you may hear a slight increase in rpm. If the engine sags, or loses rpm when
you hold the nose up, the mixture is too lean. If this is the case, slightly
richen the mixture and follow the test once more.
✦
✦
✦
✦
✦
IMPORTANT
✦
✦
✦
✦
✦
Rpm will increase about 10% - 30% in the air. This is
due to the forward motion of the aircraft as it is flying. Because of this,
more air is entering the carburetor, at a higher force, which causes the
mixture to lean out. Additionally, as the fuel level in the fuel tank goes
down, fuel draw becomes more difficult for the engine, especially during
aerobatics, thus causing the mixture to go lean. It is imperative that you
set the mixture rich while on the ground to compensate for the
leaning tendencies that will happen in the air. Always watch the exhaust
during your flight. The engine should leave a noticeable white smoke trail
at all times. If there is no smoke trail, the engine is running too lean. You
should land immediately and reset the mixture.
Setting the Low Speed Needle Valve
❑
1) Start the engine and lean out the high speed needle valve as per the
previous steps. Close the throttle until the slowest
reliable
idle is reached.
Allow the engine to idle for about 15 - 20 seconds.
❑
2) Quickly advance the throttle to full. If the engine just stops running as
soon as the throttle is advanced, the idle mixture is too lean. With the
engine stopped, richen the idle mixture about 1/8 of a turn.
❑
3) Repeat steps # 1 and # 2 until the engine will transition from idle to full
throttle smoothly. Minor hesitation in the transition is normal.
❑
4) If you quickly advance the throttle from idle to full and the engine seems
to be very rich during transition (i.e., lots of smoke coming from the exhaust),
the mixture is too rich. With the engine stopped, lean the idle mixture about
1/8 of a turn.
❑
5) Repeat steps # 1 and # 4 until the engine will transition from idle to full
throttle smoothly. Minor hesitation in the transition is normal.
Information about engine maintenance, including
adjusting the valves and returning your engine for
warranty service, can be found on the separate
sheets packaged with these Operating Instructions.
Magnum XL RFS series engines are distributed
exclusively by Global Hobby Distributors 18480 Bandilier
Circle, Fountain Valley, CA 92708
All contents copyright © 2005, Global Hobby
Distributors Version 1.0 August 2005
