Engine Break-In - Horizon Hobby Evolution 10GX2 Bedienungsanleitung

Engine Break-in

Your new engine needs to be broken in to ensure long life of all components. The piston and
liner construction is ABC (Aluminum piston, Brass Chromed liner), which requires a specific
break-in procedure that cannot be fully accomplished with bench runs. Because the ABC piston
and liner rely on the close fit of the piston to the liner to provide the compression seal, the
engines are built with a taper to the liner. For the piston to fully seat with the liner, the engine
requires repeated heating and cooling cycles, and must be done at a needle setting that is only
slightly rich of peak.
Breaking in an ABC piston and liner by running it rich does not provide the necessary thermal
growth to accomplish the needed piston and liner fitting. Using a rich needle setting does not
allow for proper expansion of the liner, resulting in the connecting rod receiving a larger force
when it moves past Top Dead Center (TDC). Allowing the engine to heat will expand the liner and
reduce the load on the connecting rod, ensuring a proper engine break-in. Doing the break-in
with a light load on the engine (e.g. a smaller than normal propeller) makes this task much
easier. Please follow the steps below to ensure a successful experience.
Important considerations during break-in
• Perform the break-in process with the engine
mounted on your airplane. There is no need
to bench run the engine prior to mounting it
on your airplane.
• Use the suggested break-in prop to begin
your break-in process. This provides a light
load and high RPM that, when matched
with the heat of the engine, will break in the
engine properly.
• Use the recommended fuel with a 20:1 gas
to oil ratio.
Break-in Process
• first tank of fuel: Set the high-speed needle
valve at 2.5 turns out and use the suggested
break-in prop. Run the engine on the ground
for its first tank of fuel and DO NOT go above
half throttle. Cycle the throttle between idle
and half throttle every minute.
• Second tank of fuel: Tune the needle valve
to be slightly rich of the peak RPM at full
throttle without a drop in RPM. Do not run
at full throttle on the ground for more than
30 seconds at a time. Tune the low speed
needle valve for a smooth transition from
idle to mid-range, go back to full throttle
to confirm the main needle valve setting
and then fly. During this flight, be sure to
be conscientious of extended periods of
heating the engine. Be sure to mix-in some
cool-down dives and lower-throttle flying.
• Third tank of fuel: Fly the engine at high
throttle while performing the recommended
figure eight maneuvers. This will help the
piston ring and cylinder liner to expand and
contract; helping the breaking-in process.
Tune the needle valve to be slightly rich of
the peak RPM as necessary.
The proper break-in flight procedure is to
fly the airplane at full throttle through a
series of figure eight maneuvers (i.e. Cuban
Eight). These maneuvers in particular benefit
the engine because, when climbing, the
additional load on the engine will increase the
temperature and, when diving, the lighter load
and higher RPM will decrease the temperature,
thus providing the heating/cooling cycles
required for the break-in process.
• fourth tank of fuel: Select one of the
recommended propellers for normal
operation and mount it on your engine. Tune
the main needle valve to be slightly rich of
the peak RPM and the low speed needle
valve for a smooth transition from idle to full
throttle and continue to break-in the engine
in flight.
Do not worry about an engine setting being
slightly rich during this process. When set
correctly, the engine will occasionally sound
as if it is misfiring (which it is). During the
climbing maneuvers this should go away and
might return during the diving maneuvers. If it
does not go away during the climbs, land the
airplane and lean the high-speed needle by
1–2 clicks, then take off and fly again. Enjoy
the break-in process—you are doing a lot of
flying.
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