Hi Gang,
Right now I only fly a trainer and 2 others that are what I would call a step up from a trainer.
I run an OS 40 and 46.
I can get non Nitro fuel for $8.00 a gallon.
Just a 2 hour ride from here.
Do these engine really put out that much more power if I go with 10% nitro mix?
I was told that the non Nitro or just a 5% Nitro mix will have better lub qualities and the engine will run cooler
I was thinking that a prop with a bigger bite would get me more power (SPEED) and I still have a cooler running engine.
Suggestions greatly appreciated

I FLEW FOR ABOUT 20Yrs. I WOULD USE FUEL WITH 10% NITRO AND 16%-18% OIL.

Joe

the best way is to try the non nitro fuel,I tried it and did not like it, big power loss

Yhanks JOE & MMC.
OK I'l go with the 10% Nitro mix.
I was going through a catalog and there are 5 different fuels made by different Companies and they all claim to have the best
BTW,
Heres the URL for that store that sells fuel so cheap.
http://www.s-whobby.com/fuel.html
I can drive there and not have to pay the haz-mat fee but it is a long ride so 16 gallons should make the trip worth while

Well I've never used nitro and never felt the need for it either...maybe we've got better air here in Oz

You don't know what you're missing.

How do you know you don't need it if you've never used it?

OTOH, most engines will run quite well on 0 nitro fuel, but run even better with just a little of the juice

John

According to Don Nix, a renown fuel expert, nitro does not necessarily increase power. In fact, if your engine is setup with rather high compression, adding nitro will cause predetonation (throws your prop off). Its main advantage in small amounts is to improve idle. With an engine specifically tuned for high nitro, it does give added power as nitomethene (and nitroethene) release some extra oxygen thus reducing the requirement for more air thru the carb. Use your search engine and look up Don Nix to find some extensive discussion on the use of nitromethene.

Hi Rodney and thanks for the info..
I guess this one topic where one can beat it to death because others will swear that the higher the Nitro mix= more power
Also when you look into engines it seems that they always suggest a higher Nitro mix.
Well so far I did well with no Nitro and just broke in the engine with the quart of 10% that came with the kit.
I'll try to do the search but I think i'm just going to stick with a 5% Nitro mix.
Thanks for writing

OK, maybe my reply was a bit short so I'll explain a bit better....hopefully

It's claimed that a bit of nitro gives easier starting. Well all my engines will start in one or two flicks...how can that be improved?

Nitro gives a lower and more consistent idle...how low do you need to go? If the model won't keep flying at idle (even a floater) or need to be held back on the ground then the idle is more than adequate.

Nitro gives more power...well if I needed those extra couple of hundred revs then I'm underpowered anyway!

I'm an Aussie so I don't have peer pressure driving me to use something I don't need

Hey downunder,
loved my visit to your country, by the way.
It's not a peer pressure thing for me. I would not know where to get fuel without nitro. Must be a USA thing.
Was running 10% nitro in a .70 Surpass. Purchased 15% when LHS was out of the 10%. Call me crazy, but I could tell there was a power increase.

A day W/O Nitro is like a day W/O Sunshine. :sunsmiley

I personally know Don Nix and wouldn't disagree with him on anything fuel related, BUT, I do believe you are not looking at the whole picture. Yes, nitro releases oxygen which in turn makes the engine run as though it is lean unless you richen up the mixture. Thus, you are burning more fuel with higher percentage nitro then you would with low percentage nitro. More fuel = more power. This is why high compression engines do not respond as well to high nitro fuel. They do not have the head capacity to handle more fuel which can lead to either decreased power output, overheating or detonation.

As far as nitro making the engine start easier. I have never heard that, nor experienced that. Nitro will keep the engine warmer at idle which will help prevent the engine loading up quite as easily. It also, in my experience, will help the engine run SMOOTHER, then no nitro. If you are running engines which are typically a little high in compression, then this wouldn't apply to you or your engine. Those of us in the U.S., where nitro is considerably less expensive than other places in the world, typically have lower compression engines and therefore can enjoy the benefits of the added nitro content. OS engines are a prime example of this. Take any two OS engines and run them side by side with the exact same prop and glow plug. Run both on no nitro, followed by 10 or 15% and check the tach. The nitro fuel will turn more revs. BTW, test can also be tried on most other engines available in the U.S. aside from the majority of the European engines which usually have very high compression ratio which I covered in the beginning of this message.

John

While I agree that more fuel = more power it's not quite as simple as that. Nitro is actually a very poor fuel compared to methanol (it's heat energy is about half) but it's more than made up for because of the air/fuel ratio it needs. In other words, you need to pour a lot more nitro into the same volume of air for it to burn effectively. This is why the needle has to be opened more for any increase in nitro % in the fuel.

One of the limiting things for nitro is the compression it can handle before detonation. This ranges from 6.5:1 at a lean setting to 10:1 when rich. Methanol however can be run at about 17:1 but seeing that nitro is commonly used then compressions have been lowered to account for this. Which is why an OS sold in America is absolutely identical to one sold in Australia. It's also why some European engines (Rossi for instance) come with spare head shims.

By simply raising the compression on an Enya 60X I got an extra 19% more HP on the same zero nitro fuel (revs increased from 11.7K to 12.5K) but what I'm curious to find out is how much nitro would be needed to have the same affect.

While I agree that more fuel = more power it's not quite as simple as that. Nitro is actually a very poor fuel compared to methanol (it's heat energy is about half) but it's more than made up for because of the air/fuel ratio it needs. In other words, you need to pour a lot more nitro into the same volume of air for it to burn effectively. This is why the needle has to be opened more for any increase in nitro % in the fuel.

Actually, it is that simple. I never said nitro was the fuel. As far as opening the needle to see the benefits of nitro fuel, I do believe I stated that as well.


One of the limiting things for nitro is the compression it can handle before detonation. This ranges from 6.5:1 at a lean setting to 10:1 when rich. Methanol however can be run at about 17:1 but seeing that nitro is commonly used then compressions have been lowered to account for this. Which is why an OS sold in America is absolutely identical to one sold in Australia. It's also why some European engines (Rossi for instance) come with spare head shims.

As do many boat, DF and car engines.


By simply raising the compression on an Enya 60X I got an extra 19% more HP on the same zero nitro fuel (revs increased from 11.7K to 12.5K) but what I'm curious to find out is how much nitro would be needed to have the same affect.

You might have to try some nitro to get that answer

John

Hey D'under

More nitro = more fun !
Less nitro = nitro ENVY

Just kidding LOL

I use the minimum that give the engine what it needs. I fly a lot at low throttle settings and the nitro helps a lot of engines with crisp transition.
Now if you can convince the Top Fuel dragster operators over here THEY don't need nitro ,"it's only PEER pressure" we might find some Aussies holding some 1/4 mile ET records.
But don't count on it

G'day mate



Te he he

.
,Hi Downunder,
I agree,
A close friend has been flying for more then 30 years.
He seems to know how to get max efficiency from the engine without NITRO.
I use 5% and just ordered 8 gallons.
I use it because the manufacture says use 10% with the OS 40.
I flew the other day when temps got to 50+ and noticed no difference so I guess 0% nitro will work as well

LF....you crack me up...