26
FLIGHT & MAINTENANCE
It is necessary to warm up the engine as with a full-size
aircraft or automobile. Do not attempt to take-off immediately
after the engine has been started. Allow the engine to run at
full throttle for at least 10 seconds before releasing the
model.
Checking before flight
Make sure that all seven cylinders are firing.
Make sure that engine runs steadily at idle speed.
Make sure that engine is fully warmed up.
Please pay attention to the matters described below to
ensure that your engine serves you well in regard to
performance, reliability and long life.
As previously mentioned, it is vitally important to avoid
operating the engine in conditions where dust, disturbed by
the propeller, may be deposited on the engine and enter its
working parts.
Remember to keep your fuel container closed to prevent
foreign matter from contaminating the fuel.
Install a fuel filter to prevent dirt and dust in the fuel
container from entering the fuel tank. O.S. Super Filters (L)
is available as an optional extra.
Install an in-line fuel filter between the tank and carburetor
to prevent foreign matter in the tank from entering the
carburetor.
If these precautions are neglected, restriction of fuel flow
may cause the engine to cut out, or the fuel/air mixture to
become too lean causing the engine to overheat.
Clean these filters periodically.
The use of modern high-performance alcohol based model
engine fuels, while promoting cooler running, improved anti-
detonation combustion and increased power, have the
disadvantage of causing corrosion due to the acid by-
products of combustion. The use of nitromethane in the fuel
can also contribute to the problem.
Care and Maintenance
Sound at full throttle changes when one or two cylinders are
not firing. With a propeller which the engine runs approx.
6,000rpm with full throttle, one misfiring cylinder will drop
approx. 500rpm and two misfiring cylinders will drop approx.
1,000rpm.
27
Do not close the needle-valve and mixture control valve too
far as this will cause a lean setting and over heating of the
engine. This can, in turn, create nitromethane oxide leading
to internal rusting of the engine. Always adjust the
needlevalve slightly on the rich side of peak rpm.
Do not leave unused fuel in the engine at the conclusion of
a day’s flying. Accepted practice is to cut off the fuel supply
while the engine is still running at full throttle, then expel as
much fuel residue as possible by turning the engine over
20-30 seconds with the electric starter. Finally, inject some
after-run oil through the glowplug hole and turn the engine
over several times with the electric starter.
When the engine is not to be used for some months (for
example, as between flying seasons), a worthwhile
precaution is to remove it from the airframe and, after
washing off the exterior with alcohol (not gasoline nor
kerosene), remove carefully the carburetor with intake pipe,
glow plug and all silicone tubing and put them safely aside.
Then, immerse the engine in a container of alcohol. Rotate
the crankshaft while the engine is immersed. If foreign
matter is visible in the alcohol, rinse the engine again in
clean alcohol. Finally, shake off and dry the alcohol ,and
inject some after-run oil in the glowplug hole and rotate the
crankshaft several times by hand. Reinstall the carburetor
with intake pipe and glowplug on the engine and keep it in a
dry place after putting in a vinyl bag.
