troyp

I have always used 5% nitro because thats what someone in the know told me to use when I first started flying. However is there any reason why I couldn't use 10% instead to get increased performance from my engine?

Perminator-RCU

First of all because it will probably not make any noticable difference, it's also more expensive.

J_R

The answer is... it all depends.

If you are flying a European engine designed for FAI fuel, you may or may not gain anything by increasing nitro. Most guys I know that try to run too much nitro can't get the engine to run right. You will also have to experiment with different plugs and props.

If you are flying a Asian engine 15% is probably fine and you may get a little more heat and power with 20%, but, probably not worth the price and loss of engine life. Most will also run on 10% just fine.

If you are using a 4 stroke, everything changes again and it could be anything from 15% to 30%. Again, the higher nitro generally leads to shorter engine life.

YS engines like 20-30%.

Plugs, altitude and props make a difference. Generally, if it is running well, why mess with it? If you want more power get a larger engine. If you can get hold of a manual for it, let the manual be your guide. The guys that designed it knew what they were doing (at least in most cases).

JR

Papa Tango

Troyp,

I see you are in Broome. Gets pretty hot during the summer, doesn't it? That's another good reason to cut back nitro to 5%. 10% at the most. The use of nitromethane will make the engine run hotter and if it's already hot out, too much could significantly shorten engine life.

Good Luck!!

hlallen867

My Feedback: (6)

Higher nitro makes an engine run hotter? I think you got that backwards my neighbor builds top fuel dragster engines and he says that one of the reasons they run nitro instead of gas is because it burns cooler he even should me a motorcycle engine he modified to run nitro and even after 10 minutes you could put your hand on the cylinder and not get burnt. As far as performance goes I don't see any difference between 10% and 15% except I seem to have a slightly more reliable idle at 15. I have never used 5% so I couldn't tell you about how it performs.

h82crash

Nitro running cooler may be true comparing gas to nitro, but the nitro does make the glow fuel burn faster, probably generating more heat. I run the big bore engines and run 0-5% nitro and my performance is better than with higher nitro. I guess it depends on the design.

troyp

Yes it does get hotter here in summer as we are in the tropics.
From the sounds of things 5% is all I would ever need.

Thanks,

Troy.

h82crash

Here's a quote from the Powermaster Fuel tech...

downunder-RCU

Troy...here in Adelaide I've never yet found the need to use any nitro at all. If 5% is the least you can get then I'd say stay with it but if you start mixing your own fuel then give it a try with zero nitro (or add about 3% acetone from the hardware shop). We're both at sea level (near enough) and neither of us get the crazily cold temps some of these Yanks seem to fly in

jaka

Hi!
5% nitro will surely improve high-speed and idle setting compared to 0% nitro!
1-3% acetone can of be mixed in (have don't this myself many times) but it can't replace nitro....sorry!

Regards!
Jan K
Sweden

Perminator-RCU

I've never run anything else than 80/20 FAI fuel and don't understand why I would want to either. It's really cheap and an Enya 3 plug takes care of all idle-problems. Going nitro would more than double my fuel expenses (when a quart of nitro costs about $25). Note that I fly all year 'round in -10 C to +30 C and low temperatures have never been a problem. But then I don't run any asian low-comp engines either.

GRANT ED

I run 5% nitro on my 2 stroke engine mostly because it seams to make them easier to tune and have a more reliable idle.

Woody 51

Troyp,

To settle the discussion, what brand of engines are you using?

troyp

Woody,

I have a OS 40LA and a Super Tigre 61.

DerFly

Troy,

Bear in mind that here in my part of Oz we (and perhaps in Broome too !)have it so much luckier than elsewhere.

We can trot off to the local fuel distributor and buy a 20l drum of Shell Racing Fuel A (97% Methanol/3% Acetone) or a drum of BP Methanol and a 5l tin of Castrol M (Castor Oil).

I got over the need for nitro YEARS ago!

troyp

Derfly,

Can you explain this methanol/Acetone thing to me a little more? I did not know that we could get by without using nitro. If so why doesnt everybody do it?

jaka

Hello!
Using 0% nitro is not a new thing. 80/20 fuel (FAI) has been around quiet a many years. Most engines could be run on just 80/20 fuel, but all of them benifits from some nitro. European engines has higher compression so they don't tolerate so much nitri as the others,usually 5-10% nitro is the norm for MVVS ,Super-Tigre, Irvine and Webra.

Someone mentioned that using nitro might raise engine temperature ...but this is not entirely tru. Using some nitro improves needle setting and gives a broader needle setting range....this gives a more precise setting which makes the engine run cooler.
Regards!
Jan K

downunder-RCU

Troy..as DerFly says, just go to the local fuel supplier (there's GOT to be one in Broome ). Shell A is only available in their own fresh 20 litre drum so you pay for the drum each time as well but it does have the 3% acetone. BP has no acetone but they'll sell it by the litre if that's all you want...take your own drum. Actually I get my BP methanol from a local Ampol/Caltex depot and they also stock Castrol M. I've even had a local auto parts shop order the M because they were Castrol dealers.

In my opinion, if you need the slight extra power you can get from nitro then your engine size is marginal for the model. I've never yet found an engine that's hard to start or tune with zero nitro. Acetone isn't really necessary, it just cuts down the ability of the methanol to suck moisture out of the air and slows down the flame rate somewhat which is handy for stopping kick back in 4 strokes at idle or starting.

Another benefit of zero nitro is that fuel consumption is less which makes it even more economical to fly with. BTW, this lower consumption is part of the reason why some people find them harder to tune. Nitro has an extremely broad range of tolerable fuel/air mixture so you can get away with dumb thumbs

NM2K

My Feedback: (14)

To me, if an engine won't run without nitro, it is junk. Put your money in a better engine and leave the poison to others. Nitromethane is just another toxic compound that is to be avoided. Not to mention the added expense.

It is good to see that there are still some sane people left in the world that live without this poison.

patternflyer1

My Feedback: (11)

[QUOTE]Originally posted by Artisan
[B]To me, if an engine won't run without nitro, it is junk. Put your money in a better engine and leave the poison to others. Nitromethane is just another toxic compound that is to be avoided. Not to mention the added expense.

Well what engines are you running that aren't junk?There are nothing wrong with nitro engines and I would put mine up against any. Any day of the week. Sounds like you don't know to much about them or you may not know how to set them up. But this is my opinion of your opinion. You may well know, and just don't like em. I agree they are more work though..

NM2K

My Feedback: (14)

I used to fly pattern when FAI forbade the use of nitromethane. It should still be that way today as engine development would be much further along than it is presently.

When everyone competes on even ground, no one misses things like nitromethane. The move in pattern toward more nitro and larger aircraft was but a sneaky means of eliminating very good pilots with shallow pockets.

To talk with most pattern pilots, you would think they are racing enthusiasts, not aerobatic pilots. All they worry about is how much "power" they have available. Pattern has strayed from its original purpose to the point that many refuse to participate for just this reason.

What tickles me is what I see coming over the horizon. The electric boys are going to kill the pattern game as it is presently being played. You nitro heads (generically speaking - nothing personal intended) will have to find some other venue in which to play your nitro games.

Of course what I am saying is just my opinion. No one else need agree at all.

downunder-RCU

OK, to put this into perspective, just because an engine has what's called "low compression" doesn't mean it absolutely HAS to use nitro. Low compression nowadays generally is around 9.5:1 whereas the European engines run close to 11:1 compression. Now take a look at the Fox 35 (OK, so it's a CL engine and doesn't have to idle) but the early versions had a compression of 5:1 and the later ones have 6:1. The recommended fuel for them was 5% nitro but some guys would use more. Compared to them, every engine made today has an ultra high compression

LOONY BOY

I called shell today and got a price on shell racing A only $A52 for 20 liters and $A58 on castrol M castor oil 5 liters.
Looks like I won't have to go to the LHS for fuel anymore.
Thanks for the info
LOONY BOY

Sport_Pilot

Funny but most people I know consider an engine that cannot run on more than 10% nitro is junk. As for me I like nitro for speed, for just chugging around I prefer an engine that is suited for 15% nitro, easy to tune and more nitro. If its a large engine I prefer those low nitro engines even though they are a bit harder to tune. They use less fuel with low nitro.

Sport_Pilot

I don't understand this one. I don't understand how using low nitro impoves engine research. Not much research left to be done, just more knowledge to be used from full scale engines, and further use of microprocessors. I don't undestand why someone who can afford expensive pattern planes cannot afford the moderate amount of nitro now allowed. And I don't undestand why someone would want to fly underpowered pattern planes. Here of going verticle?