First of all you
really don't want to "BREAK-IN" an ABC or AAC engine
in the classic sense. An ABC
type engine (Aluminum, Brass, Chrome) does not require
prolonged break-in periods. However, we do recommend that
you run the engine at a slightly rich needle valve setting
for the first two runs. These runs should be made with the
engine installed and running for not less than five (5) minutes
periods. Typically an engine will be ready for continuous
full throttle and a leaner needle valve setting after ten
(15) to fifteen (20) minutes of running.
ABC
engines are designed to run at operating temperatures, NOT
COOLER temperatures.
RUNNING THE ENGINE TOO RICH WILL RUIN THE FIT.
If the operating temperature is not reached, the piston is
prematurely worn from lack of clearance. You do not want to
"break-in" an ABC engine at a very rich setting.
Just a slightly rich setting for the first 30 to 45 minutes
of running is adequate.
A model
engine makes sounds that will tell you how it's performing.
You'll have to listen very carefully for them, recognize their
message, and make adjustments to the fuel control needle valves
accordingly. The mixture of fuel and air is controlled by
the amount of fuel metered by the needle valve.
SLOPPY
RICH MIXTURE running is characterized by a very slow,
irregular, sputtering exhaust sound. The exhaust gas will
be very smoky and contain many droplets of oil. NEVER RUN
AN ABC ENGINE AT THIS SETTING. The cylinder is not able to
heat properly and the fit will be ruined in a short time.
RICH
MIXTURE running is characterized by a slower, sometimes
irregular, sputtering exhaust sound. The exhaust gas will
be smoky and probably contain small droplets of oil. NEVER
RUN AN ABC ENGINE AT THIS SETTING. The cylinder is not able
to heat properly and the fit will be ruined in a short time.
FOUR
CYCLING or SLIGHTLY RICH running is a rich type
setting, but it is fast enough to pull the airplane. This
is the setting you normally look for before launching the
airplane because the engine will run leaner when airborne.
PEAKED
OR TWO CYCLE. As the main needle is closed (clockwise),
it reduces the amount of fuel mixed with the air drawn into
the engine. At a specific point, which varies with each engine,
air temperature, altitude and relative humidity, the exhaust
note will change quickly into a smooth, powerful note. If
the needle is closed further, the note will stay smooth, but
will weaken. The peak occurs just at the break point from
a rich setting and further leaning will ruin the engine. A
lean setting raises the engine heat above the safe point,
reduces lubrication, and destroys glow plugs due to high combustion
temperature. This is very harmful to the engine and your investment.
Learn to tune the engine before flying. Remember, a little
rich is always preferred for long motor life.
AIRBORNE
BREAK-IN
1> BREAK-IN
running should be done with the recommended propeller at a
slightly rich setting. You want the engine to be at
running operating temperatures. The needle valve should be
set at a point just into this range from a four cycle setting.
Fly the plane at maximum throttle for 2 minutes, then throttle
back to half throttle for approximately 30 seconds. Repeat
this sequence until approximately 20 minutes of accumulated
running time has been obtained. Additionally, certain maneuvers,
such as "CUBAN EIGHT'S", that allow the engine to load and
unload are recommended. AVOID PROLONGED CLIMBING MANEUVERS
AT MAXIMUM THROTTLE.
2> After the
first 20 minutes change to normal size prop and fly an additional
15 minutes. Continue to run the engine at a slightly rich
setting and fly your normal pattern.
3> After the
above break-in period, run the engine at a normal peak needle
valve setting. This should be a little on the rich side because
engines run leaner in the air. 5% - 15% nitro may be used.
BENCH BREAK-IN
NOTE THAT THE
ENGINE MUST BE FIRMLY MOUNTED ON A SOLID TEST STAND. DO NOT
CLAMP ENGINE IN A VISE. Muffler may be used during bench break-in.
The initial bench
break-in period is also approximately 15 minutes (15 minutes
bench and 15 minutes airborne). During this time, use the
recommended break-in propeller and run the engine at a slightly
rich setting. It is best to run the engine for a full 10 minutes,
then allow it to cool. Heating and cooling is not beneficial
to an ABC engine as you what it to run at operating temperatures,
not cooler temps.
1> Start the
engine and run it at a slightly rich full throttle for about
2 minutes, then let it fast idle (about 3500 rpm's) for 30
seconds. Repeat this sequence for about 10 minutes of running
time.
2> Increase
the full open throttle time to about 3 minutes followed by
a 30 second idling period. Do this for an additional for 20
minutes.
3> Install
the engine in your aircraft using an normal size prop.
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