Fuel FAQ
The most important ingredient of any model fuel is oil. This is the only means of providing lubrication and is
important for engine operating temperature. The golden rule of fuel is ... if in doubt run more oil.
Never run an engine with an unproved oil. Without doubt castor oil is still the best for lubrication. Occasionally
castor is not the chosen oil because,
a) It is very messy.
b) It wont mix well with high nitro content fuels (say above 40%), or petrol.
c) The higher viscosity sometimes doesn't agree with pump / carby settings. If allowed to stand a while castor
will 'clag' some pumps
Our chosen synthetic oils are the Morgan's, Cool Power, or Powermaster. These oils have good results and
reputation whilst having a very good rust inhibitor. (Needed when running nitro).
METHANOL
Methanol is the major component of most fuels. It is important to use a good clean grade. Take care as some
methanol’s include other ingredients such as acetone.
NITRO METHANE
Nitro is a power enhancer as it increases the amount of oxygen available in the fuel for combustion. The down
side is that it generates more heat (often needs a lower combustion ratio) and can contribute to rusting of the
engine (caused by the acidic by-products of the combustion). The use of small amounts of nitro will help most
engine run smoother.
Nitro methane will not increase rpm, but as it’s combustion produces more energy, the engine will develop more
torque, allowing the use of bigger propellers, or better operation under high loads. A classic example of this is
R/C aerobatics where adding nitro to the fuel will give a big performance increase in vertical climbs.
PETROL
For large spark ignition engines (although sometimes added in small percentages to glow plug fuels), use
the leaded versions of petrol as this aids the lubrication process.
FUEL MIXES
For 2 stroke engines above .120, we use 10% Synthetic, 5% Caster, 10% Nitro and 75% Methanol. Engines
above .180 can often go as low as 10% oil content. Big prop loads need more nitro.
For .60 Pattern and large 4-strokes, 15% Synthetic, 15% Castor, 15% Nitro and 55% Methanol.
For C/L Aerobatics and other very low RPM uses we use 12% Synthetic, 12% Castor, 6% Nitro and 70%
Methanol.
For General Sports Flying we use 10% Synthetic, 10% Castor, 5% Nitro and 70% Methanol.
For large scale flying we use 5% Synthetic, 5% Castor, 5% Nitro and 85% Methanol.
For large petrol engines we use 6% Synthetic, 6% Nitro and 88% ‘Super’ (leaded) Petrol.
For those who mix fuels themselves, be very sure of thoroughly mixing the fuel, castor in particular requires
thorough mixing.
PLEASE NOTE
Where possible, run one or more fuel filters. Use good quality one's
as many of the cheap old
style filters will leak or cavitate the fuel.
Using restrictive exhaust systems or tuned pipes place excessive strain on your engine and lubricant. Make
certain your fuel contains the suitable type and quantity of oil. It will not only reduce friction but it will also help to
cool your engine, this is especially so with pattern 4 strokes.
Nitro methane is used to provide the torque to drive larger propellers. The Nitro will allow bigger props to run at
the same RPM. For Pattern flying it's the difference between 12 x 12 and 12 x 11 at 10 000.
When in doubt, use more oil always.
Dubai RC Hobbies