Well..... I been associated with use of glow engines up to .60 cu in and used Nitro Methane just a few times... i.e. when doing some show flying and you need that extra kick from the engine..... or else used just Methanol and Castrol oil as fuel..... nothing else.
OK.. the pros and cons of using Nitro Methane.

Pros.....
1. Being a compound of explosive nature it improves the fuel burn capacity of the engine.
2. This gives a slight increase in power output.

Cons.....
1. Being a compound of explosive nature it is a controlled item and its sale is supposed to be regulated.
2. As it increases the fuel burn capacity the engine works at a higher temperature.  Cooling has to be good or else the wear and tear on the engine will be quite high.  Resulting into early wearing off of the cylinder & piston.
3. It may be used for a partially worn out engine where one finds a bit of loss of power.

OK... what to do

1.   Nitro methane gives a boost of about 2-5% of engine power depending upon environmental conditions but causes 2-5% higher wear and tear on the engine.  Guess for higher engine life I WOULD AVOID USING NITRO METHANE TILL THE TIME I JUST CAN NOT DO WITHOUT IT.

2.   After using nitro methane make sure you wash your engine properly.  The best way is to open it up completely and wash it with KEROSINE (do not used methanol as a cleaning agent as it leaves marks on the engine and being a volatile substance may effect the engine components).  Allow the parts to dry (an hour in the open) and then apply any 2T oil while fixing it up.  This will ensure you avoid any un-necessary scratch on the sensitive parts of the engine.  Be sure to clean the fuel needle assembly also.

3.   Keep the engine covered by a piece of polythene at all times when not flying.

4.   In case you need some compound to boost engine out put it is better to use commercially available PETROL fuel-additives (ones available at the petrol station).  They assist in better fuel burn and also keep the engine clean and are made in a manner to conserve engine life and health.  I use it regularly for both my Diesel and Petrol (Glow) engines.

5.   Last but not the least.  There are only two types of engines used here... they are Diesel engines (one which do not have a glow plug or a spark plug and use a mixture of Either, Kerosine and castor Oil as Fuel), the other engines are Petrol engines (one which have a Glow plug or a spark plug to assist ignition of fuel).  Nitro is a word used for fuel when it is laced with Nitro Methane or other Nitrogen additives.  Remember Formula 1 cars run on Nitro fuel as they need that engine to produce every ounce of power for that race (the driver / team is not interested what happens to the engine after the race) and other cars used plain commercial petrol as the owner is concerned about the life and health of the engine.

Morale of the story......  You may stop using the so called NITRO FUEL and have a longer and healthier engine life of that costly equipment.  If still looking for additional power with care... use the commercially available FUEL ADDITIVES available at the petrol station.

Hi,

Can you point me towards which Fuel Additives shall we use for glow engines? Any specific names which you recommend?

Regards

Doc

Shobhit ji , sum up clearly.
just a silly question .
if diesel  engines don't use spark plug or glow plug, how the fuel is ignited ?

Compression Ignition. If you compress a gas it gets hot

Technically a Glow Plug Engine too is compression ignition - the plug helps by remaining hot, but it is not Spark Ignition (like a spark plug - gassers and automotive engines)

Thanks sanjay sir

To set couple of things right
 No1. After using nitro methane make sure you wash your engine properly.  The best way is to open it up completely and wash it with KEROSINE (do not used methanol as a cleaning agent as it leaves marks on the engine and being a volatile substance may effect the engine components).
My suggestion, do not use kerosene to clean your any engine parts that have rubber. Like needle 'O' ring or gasket 'O' rings. Kero will  help them grow  .
Correct you should avoid Meth for cleaning not because it leaves mark on engines but due to the reason that it is hygrosopic, which means that water absorbed by Meth will help oxidation of engine parts. However if one takes care, Meth can be perfectly used. But immediately after cleaning, dry the parts and lube them up using your preferred lube, yes 2T oil works perfect.   
 
 No 2 - In case you need some compound to boost engine out put it is better to use commercially available PETROL fuel-additives (ones available at the petrol station).  They assist in better fuel burn and also keep the engine clean and are made in a manner to conserve engine life and health.  I use it regularly for both my Diesel and Petrol (Glow) engines.
Before using any additive meant for petroleum product fueled engine check if it is compatible with alcohol fuel. Not all are.

No 3 -  There are only two types of engines used here... they are Diesel engines........... the other engines are Petrol engines
Technically in model IC engines there are broadly two type, compression ignition and spark/glow ignition.

No 4 - Yes glow engines are compression ignition as well, however the compression ratio is much lower than a model diesel engine that relies on compression to ignite the fuel charge. And a glow filament helps by acting as a catalyst for breaking down the Hydrogen and Oxygen present in Alcohol based fuel of model engine. The heat you supply helps in accelerating the reaction.