Glow Plug - O.S. engine MAX 140RX FI Owner's Instruction Manual

If the engine produces a higher pitch sound immediately after taking off or if the engine appears to
lose power and exhaust cannot be seen at all (although varying somewhat depending on the fuel),
turn the injection trim adjustment dial (spare channel dial) in the (+) rich direction by about 45˚ with
the throttle stick in the full high position and reconfirm engine operation by continuing to fly for 3-4
minutes. (When this is difficult to evaluate, land the airplane and recheck engine speed with the
throttle stick in the center and full high positions.) When there is still no change even when the
above adjustment has been made, land the airplane and try readjusting from the first step of the
adjustment procedure. This completes the adjustment procedure.
Once adjustment has been completed, when the airplane is flown again, simply recall the TMD
menu by pressing the function key. The display changes from the Fine menu to the ATL menu.
(Fine adjustment data continues to be stored in memory.) Next, switch to the ATL adjustment
menu. The function of the injection trim adjustment dial changes to that during Fine with full high
corresponding to 100% (see the previous section on TmD ATL) based on full slow corresponding
to the origin. It is recommended to use this menu during routine flights. Repeat the fine adjustment
procedure described above whenever the propeller or fuel and so forth has been changed.
GLOWPLUGS
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 TYPE F. Carefully fit plug finger-tight, before final tightening with the
correct size plug wrench.
The role of the glowplug
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.
Glowplug life
Particularly in the case of very high performance engines, glowplugs must be regarded as
expendable items.
However, plug life can be extended and engine performance maintained by careful use, i.e.:
• Fit 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.
When to replace the glowplug
Apart from when actually burned out, a plug may need to be replaced because it no longer
delivers its best performance, such as when:
• 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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