10
FUEL
The FS-120S-E should be operated on a methanol based fuel
containing not less than 18% castor-oil, or a top quality
synthetic lubricant (or a mixture of both), plus a small
percentage (5-15%) of nitromethane for improved flexibility
and power. The carburettor is adjusted at the factory for a fuel
containing 20% lubricant and 10% nitromethane.
Some commercial fuels also contain coloring additives as an
aid to fuel level visibility. In some cases, these additives have
indicated slightly negative effects on performance. We would
suggest that you use such fuels only if you are satisfied that
they do not adversely affect running qualities when compared
with familiar standard fuels.
When changing to a fuel brand or formula that is different
from the one to which you are accustomed, it is a wise
precaution to temporarily revert to in-flight running-in
procedures, until you are sure that the engine is running
entirely satisfactorily.
Reminders:
AII model engine fuel is poisonous.Do not allow it to
come into contact with the eyes or mouth. Always store it
in a clearly marked container and out of the reach of
children.
Though not as volatile as gasoline, model engine fuel is
also highly inflammable.
Keep it away from an open flame, excessive heat, sources
of sparks, or anything else that might ignite it. Smoking is
firmly discouraged.
Since the FS-120S-E is intended to be started with an electric
starter, the addition of a spinner assembly for centering the
starter sleeve is desirable. Special propeller locknut sets are
available for use with spinners.
Use a good quality well balanced spinner, enclosing the
propeller boss. Make sure that it is of precision-made and
sturdy construction so that the spinner shell cannot loosen
when the starter is used.
Make sure the spinner notches do not interfere the propeller.
If they do, cut the notches to clear off.
11
GLOWPLUGS
The role of the glowplug
Glowplug life
Particularly in the case of very high performance engines,
glowplugs must be regarded as expendable items.
Install a plug suitable for the engine.
Use fuel containing a moderate percentage of nitromethane
unless more is essential for racing events.
Do not run the engine too lean and do not leave the battery
connected while adjusting the needle.
However, plug life can be extended and engine performance
maintained by careful use, i.e.:
With a glowplug engine, ignition is initiated by the application
of a 1.5-volt power source. When the battery is disconnected,
the heat retained within the combustion chamber remains
sufficient to keep the plug filament glowing, thereby continuing
to keep the engine running. Ignition timing is 'automatic' :
under reduced load, allowing higher rpm, the plug becomes
hotter and, appropriately, fires the fuel/air charge earlier;
conversely, at reduced rpm, the plug becomes cooler and
ignition is retarded.
Apart from when actually burned out, a plug may need to be
replaced because it no longer delivers its best performance,
such as when:
When to replace the glowplug
The FS-120S-E is supplied with an O.S. Type F glowplug,
specially designed for O.S. four-stroke engines.
Filament surface has roughened and turned white.
Filament coil has become distorted.
Foreign matter has adhered to filament or plug body has
corroded.
Engine tends to cut out when idling.
Starting qualities deteriorate.
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