Hi there,

As this topic must've been discussed earlier prolly in other threads but I gotta ask couple of questions about Nitromethane. Nitro which mostly I read here is 15% best for the engines and most of the people and senior flyers have been using it either it's 2C engine or 4C engine.

In Pakistan, here we generally prefer and use 80% methanol 20% castor oil mix which is popular in European countries as I read it here and it has a particular name I dont remember it. This exact 80/20 mixture we use it here and we don't use Nitro as its ofcourse expensive here as well, but its available at the LHS who make it locally not company made fuels which are available in USA. A senior flyer who is our friend goes to flying with us, he says Nitro fuel basically reduces the life of an engine either 2C or 4C as he said its his experience. My question is that does really nitro reduce engine's life? As per my knowledge nitro is used as a catalyst and it helps burn fuel more efficiently so engine performs well with higher rpms. Second question is, if we use 15% nitro on any engine after a gallon on it and then we use 80/20 would it make any difference in engine's performance or would it reduce it's life?

Please clarify me as in future in USA I'd like to use nitro in all engines I would use there.

Thanks in advance

Mody

Nitro does not reduce engine life.

It does change the ratio of air to fuel, change the temperature of combustion, and that can change the timing of the combustion wave, and change the amount of heat carried away by the exhaust. All of these things have an effect on an engine that is set up to run 80/20 fuel.

Amounts of nitro in the fuel under about 30% nitro can often make setting the needle valve somewhat easier. It often broadens the needle response. But if you're used to setting the needle for 80/20 fuel, this doesn't matter much at all.

Nitro sometimes works better with an igniter. I think it was propylene oxide that we used. But we used very small amounts.

We sometimes encountered engines that ran well on 80/20 that didn't on nitro fuel. Changing the compression ratio usually restored the good running characteristics of those engines. Matter of fact, when we changed the nitro content measurably, we often had to swap in or out a head gasket or two.

For sport R/C flying, I use 10% nitro year round. Higher percentages simply aren't worth the expense. I was using 5% but the LHSs quit stocking it.

Whenever you change fuel, and the change results in a measurable difference in combustion temperatures, engines may react to the change.

Non-ringed pistons fit the engine sleeve based on the temperature they encounter when running. If that changes measurably, the piston/sleeve fit might be affected. Ringed engines won't always show as obvious response.

An engine's life is usually affected most by the friction it encounters. If you run the engine at higher rpm, it's going to encounter more friction.

Da Rock,

Thank you very much, It has cleared a lot of confusion of my mind and I gotta tell it to our senior flying friend which had bad experience of nitro. Second thing is whatever the fuel we use either its 15% or more with nitro, can this fuel be used in 4 strokes as well?

Mody

Hi!
Your friend must have missunderstod it!
What nitro does is enhance your ability to set the engine correctly. It broadens the fuelneedle setting and makes the engine run cooler if set correctly.
By using nitro You can get a more perfect engine setting which makes the engine run cooler, reducing wear and tear.
Personaly I use 5% nitro in my fuel, I mix it myself , consisting of 15% Motul "Micro" a French all syntetic oil , 5% Nitromethan and 80% Methanol.
Most flyers over here in Sweden do use nitro, 5-10% seems to be the norm.

Thanks Jan K

I never agreed with him, but wondered that how can he say that, despite he is 60+ in age and had vast experience of flying as well as building model airplanes. Why does he have this notion about nitro reduces engine's life. What if it does, why would all the people be using it mostly in USA. Thank you all for clarifying it to me.

Mody

Some people get something in their heads with absolutely no basis in fact. Once that's done, it's sometimes next to impossible to change their minds. It's also usually impossible to reason with them. For example, my mother in law thinks it's perfectly ok to leave meat and other foods on the counter all day, or over night. I've tried to get the message to her, through my wife since mother in law doesn't speak English, that this is extremely risky. Even my wife isn't convinced despite me showing her info online from the FDA and various other food safety sites. I finally cured them of it by throwing away stuff I find that's been left out too long. They still don't believe me, but they know that putting things in the fridge is the only way to keep me from tossing it in the trash.

When you encounter information you can accept it, question it, which can often lead to hard feelings, or just politely listen to what they say and go research it so you can form your own conclusion. Much of what "old timers" say is based in fact, so don't blindly dismiss what they say.

Hey Armody, the guys are correct. No harm from the nitro and fuel without nitro is usually called FAI fuel.

I'll back up what everyone else has said that nitro won't affect the life of the engine with the caveat that you use enough oil (and good oil) and that the % of nitro is suitable for the engine. You can run in an engine on whatever fuel you like and swap around between different fuels whenever you like and it won't do any harm so long as you retune to suit the new fuel.

Your 80/20 fuel is called FAI fuel but only because that's the mix required in a couple of competitions run under FAI rules. In America it's become common to call any fuel without nitro FAI to the point where some companies (Morgan for one) sell a fuel called FAI but it isn't. I haven't made up my mind whether they don't know what they're talking about or if it's just false advertising .

I've never yet come across an engine that doesn't start and run perfectly well on zero nitro so to me nitro is more of a fashion accessory unless you're in a competition where you need every bit of power possible. This applies to 2 strokes because I have zero experience with 4 strokes.

I use 30% Nitro in all my 4 stroke engines (mostly YS 110) and 15% in my 2 strokes. I tried 30% in my OS160FX and promptly seized up the engine. It just pinged and run terrible. So I say Nitro can harm an engine is not used properly. I also say that you get much greater performance with higher ratio nitro. That leads to more RPM, bigger props, better transition, better running and more fun. It also leads to shorter engine life, I believe.

Having said that...I'd run even higher nitro in my YSs if I could readily get it. I love the stuff. However it is addicting.

Thanks
Barry

Using Nitro in the 5-15% with at least 20% Oil won't affect the life of an engine, However when using higher %'s of nitro the engine life will be reduced especialy over 50% nitro. When I used to race boats in the 80's I used 60-70% nitro and 20-25% caster and the engines would only last a couple of hours where as the practice engines that I used on 10% nitro would last forever. After I stopped racing I went to 5% nitro for a while and then to 0% in all engines and when tuned correctly you have no problems with them.

Cheers

Hello; It is my understanding that nitro works by releasing oxygen when it burns, which makes for a bigger bang and supports better alcohol cumbustion. More nitro=more oxygen released=bigger bang. Nitro is also a powerful solvent, and in sufficient concentrations, will wash away the oil film that protects friction surfaces. I think that the potential is there for nitro to damage engines, but, like the lubricating oil in the fuel, it is constantly being flushed out of the engine by the total loss oil system our engines operate with.

So your friend has thought it through, and come to his conclusion through a logical process. It's just that experience doesn't prove his theory.

There is a caveat to this. Nitro can cause premature harm if you have a lean run. Nitro is a monopropellent, that is it can burn with no additional air, however it is hard to ignite. This is why those AA Dragsters have huge magnetoes, to ignite an extreme rich mixture. If they get the mixture to rich, or the mags are weak, then they have cylinders "drop out" or miss. You can see clouds of raw fuel come out of the exhaust when this happens. To get to the point, this is why it broadens the needle and why the engine runs cooler. The nitro will provide more and more power as the needle is richened, but the methanol will provide less, the opposite will happen when you go from the rich side of the peak to the lean side. But when run lean the nitro will instead run much hotter than the methanol, add some detonation and you can quickly ruin pistons, sleeves and bearings.

Armody, nitro methane is an oxidizer. It assists the internal combustion as it needs little (in some cases none) outside oxygen to sustain combustion. For example while gasoline needs 14.6 # air per # of gasoline to sustain internal combustion, nitro need only 1.7#.

Nitro will therefore increase performance up to a point. With good lubrication your engine will be OK for its normal life. OTOH great amounts of nitro can harm the engine such as racers do because of the ultimate performance so demanded. I lost a few rods and crankshafts back in my racing days.

Nitro has a high flame temp. however at the lower levels of normal uses, the extra oxygen produced usually runs a cooler head temp.

Nitro flash point is 110*F. Fairly safe as compared to methyl alcohol and gasoline.

Both nitro and alcohol have oxygen in its molecular structure. However that molecule is the first to react to the broken bond when it burns and does noting to the metnanol. Pure nitro provides much more power than any nitro-methanol mix. Any addition of nitro reduces efficiency, not improve it. It increases power simply because it increases the mass flow through the engine. Remember power is force applied to proved work over time and force is mass * acceleration.

First of all Thank you very much all you posted in here, what I concluded is that, naturally excessive use of nitro or it's higher percentage may cause an engine damage, which ofcourse nobody would like that. Nitro is not harmful, its an additive to add extra power, extra RPM as well as easy engine tunning.

I'd like to ask Piper Chuck, from which country your mother in law belongs and which is her first language? spanish?, as my first language is not english its Urdu and my wife's first language is English. People ask me why my wife can't speak my language, so I say that I don't have problem talking to her in english so thatswhy she never learned where as my son 6 1/2 speaks my language perfectly with few masculine & feminine mistakes as he is from my wife's first husband and I love him as my own son. My wife still gets amazed how he speaks her husband's language main reason, he interacts with kids a lot, his whole life is revolving around playing lol .

Well, as far as Im here in Karachi, Pakistan, I'm using that FAI fuel 80/20, upon arriving to USA I'd be using 15% to 20% Nitro. Thanks to all for your replies. If anyone likes to add further clarification to it, It would increase my info more.

Mody

Unless you have a specific need for it, don't waste the money on 20%. 10-15% is fine. I use 15% but would use 10% if my club sold that at the discount price.

Bruce Thank you very much,

Well, I'd use the fuel as you advised but only upon arriving to USA, and probably I'd like to stay in touch with you on the phone just desperately waiting to get my US immigrant visa. I'd like to use 4 stroke engine in future as well.

Thanks again Bruce

Mody

Wow alot of great info here! I learned a few things just reding through this thread. I have always used 15% nitro in all my planes. They all seemed to run great on it and that includes 4c and 2c. My biggest reason for this is I am cheap and don't want a bunch of different types of fuel laying around the house.

Also Mody I would like to wish you good luck for getting your Visa here to the US. I think you will be blown away by all the new options you will have in this hobby here.

TruBlu02

Thank you very much for wishing me luck for my Visa I really appreciate that. Yes, I would like to have a good collection of planes engines and radios in USA which is ofcourse a Land of Opportunity. Never used Nitro here but in USA I'd be using it. YOu are in Arizona I think and my wife says its pretty hot, though my city itself is very hot, but I'd like to see that state too someday. The R/C stuff available in USA are really amazing and it would really blow me away. Im sure. Thanks again trublu and to all.

Mody

Actually I am Located in Arkansas. But it is still very hot here but humid. Probably like where you live. I have actually been to Pakistan once while serving a tour of Duty with the Air Force. I was at Jacobabad Air Base just outside the city. Beautiful country. Not what I expected at all. In fact it looks alot like Central California. And again good luck!

Wow, thats great trublu, if you saw my city Karachi, you'd be pretty amazed anyway, I sent you a PM and hoping you got it.

Thanks again.

Mody