O.S. Engines 46FX-H Ring - Manual (Page 11)

FACTS ABOUT GLOWPLUGS
The role of the glowplug
Glowplug life
Particularly in the case of very high performance
engines, glowplugs must be regarded as expendable
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 become
cooler and ignition is retarded.
Since the compatibility of glowplug and fuel may have
a marked effect on performance and reliability, it may
be worthwhile to choose the R/C type plug found
most suitable after tests. Recommended O.S. plugs
are No.8, A5 and A3. Carefully install plug finger-tight,
before final tightening with the correct size plug
wrench.
12V Battery
Starter
10 Electric starter and starter
battery
An electric starter is recom-
mended for starting.
9 Hexagon starting shaft
This shaft mounted on an
electric starting motor is driven
into the main body of a
helicopter to turn the engine.
10