O.S. Engines FS-40S - Manual (Page 14)

Fuel
Use a good quality commercial fuel or one of the
blends shown in the table. Fuel "A" is suitable for
running-in and ordinary use. Fuel "B" is for use
when more power is required and for improved
flexibility. Note that even a small quantity of
nitromethane (3-5%) will improve flexibility,
making the needle-valve adjustment less critical
and improving throttle response. Use only
materials of the highest purity. Synthetic oils are
permissible but are less tolerant of a "lean run"
than castor-oil. If, therefore, a synthetic lubricant
is used in the fuel, readjust the needle-valve to
a slightly richer setting, as a safety measure, in
case the fuel/air mixture becomes too lean
through maneuvers in flight. higher nitro fuel is
used, the engine should be checked out to make
sure that it is sufficiently run-in to operate on that
particular fuel without overheating. Do not use
fuels containing less than 18% lubricant.
ADVICE ON SELECTION OF FUEL, GLOWPLUG & PROPELLER
A B
75%
20%
5%
65%
20%
15%
Methanol
Castor Oil
Nitromethane
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.
Model engine fuel is also highly flammable.
Keep it away from open flame, excessive
heat, sources of sparks, or anything else
which might ignite it. Do not smoke, or allow
anyone else to smoke, near to it.
Reminder!
PROPELLER
Suggested propeller sizes are given in the table. As
the ideal propeller diameter, pitch and blade area vary
according to the size, weight and type of model, final
propeller selection will require in flight
experimentation.
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