jentzsch

So I live at ~4500 feet. I have been using the 20% nitro. Would I benefit from going to a higher nitro %?

wjvail

My Feedback: (3)

Short answer... In all likelihood, yes. Nitro brings oxygen to the combustion process and since your engine is likely under-compressed from the altitude, you are a good candidate for more nitro. Please keep in mind, your engine will run OK with no nitro, but you will notice an improvement in "needle-ability" and throttle response with nitro at your altitude. At 4,500' you should not have to worry about adding shims.

Bill

Edfltchr

I keep hearing you guys about running with no nitro, what fuel is it and what would be the mix, and is it cheaper than 25$ a gallon?

JB COMP

I live not to far away from you (Navarre, FL) where do you buy your fuel at? I get mine from a guy in FWB (Fort Walton Beach) and he has Morgan fuel's (Sidewinder, CoolPower, Omega) and a gallon of 20% of Sidewinder is $14 a gallon and the other two will be close to that (if you fly planes)

It would be about a 1 1/2 to 2 hours drive for you, you might just want to buy a case at a time (4gallons) or even go lower nitro % and save a little more.

PM if you want his name and stuff.[8D]

downunder

It's just a mix of methanol and oil which is the basic fuel for any glow engine. Nitro is just an additive but all engines are designed with low compressions so they can handle having nitro in the mix although they'll still run quite well without it. I mix my own fuel and at the prices I can get both the oil and methanol it works out to be about $10 a gallon but if you factor in the lower fuel consumption compared to normal car fuel it works out being closer to $7.50 a gallon. Most major fuel companies like Sig, Fox, Powermaster and so on have either zero nitro blends or 5% nitro.

Argess

Here's a good read:

http://www.*********.org/understanding_fuel.htm

atul

Downunder: one of your previous posts said that you use 20% castor oil in your fuel (with 0% nitro). I plan on using 0% nitro (mainly because high-quality Nitro is difficult to come by in India - where I spend 50% of my time). The above link provided by Argess talks about 8% to 12% oil.

So will a mix of 90% methanol and 10% castor then be ideal?

I plan on running in a brand new RB S7 this weekend, so any comments would be helpful!

On the same note, I've got a YS-110 Airplane engine and the manufacturer recommends 15-30% nitro. I wonder whether 0% nitro may be too much of a risk on this engine. Downunder had previously said that he ups the oil content when Nitro is lowered since less fuel is burned, so perhaps a mix of 78% Methanol, 20% Synthetic and 2% castor will work will for the YS-110? The YS engines do not like too much castor since it messes up the internals of the fuel system (clogging, etc. due to its stickiness).

Thanks,

Atul

downunder

Not really. Because of the much higher fuel consumption with high nitro a fuel with 12% oil would flow roughly the same amount of oil (per minute or whatever) as a zero nitro fuel with 16% oil. With 10% castor in yours and no nitro that'd be somewhat the same as a high nitro fuel with 7.5% oil.

As for the YS, it'll certainly run on zero nitro and do no harm at all but because it's designed to use lots of nitro to help close the power gap between 2 strokes and 4 strokes you might find a fair loss of power. That's assuming the regulating system that YS use will handle the much leaner mixture needed by zero nitro.

atul

Thanks for the quick reply! Just to be certain, should I then go with the regular 20% castor and 80% Methanol mix for the RB? Please advise. Or should one stick to the 16% that you've indicated above? I normally use 20% on my model airplane engines (Rossi, Jett - they all love 0% nitro).

On the YS front, I have no issues with a loss of power. I'm getting it because of the cool sound mainly and because of the mid-range throttle response. But I have a fundamental question. Why is a much leaner mix required with zero nitro? I mean, one can simply make the mixture a little richer, right? In theory, simply opening the high-speed needle more should do the trick. What am I missing here?

Thanks!

atul

downunder

atul
I'd go for the 20% oil same as you use in your planes (same as I do actually and also have a Rossi 45...but no Jett ). That extra 4% gives added insurance.

As for the mixture with zero nitro, here I'm using the commonly accepted term for turning the needle in to lean a mixture but what's really happening is that zero nitro has a completely different air/fuel ratio to any fuel with nitro so the needle is adjusting the air/fuel ratio to match the type of fuel being used. Which is all the needle valve does anyway . Technically, methanol had an air/fuel ratio of about 6.5:1 while nitro starts at 2.5 and can be as rich as 0.5:1 so a blend with nitro falls somewhere between these extremes. The more nitro in the blend the closer it get to the 2.5 or less. At a guess a 25% nitro fuel would have an air/fuel ratio probably around 4:1 which is why it uses up fuel faster from the tank than a zero nitro fuel.

atul

Thanks. This is certainly very useful information.

What I fail to understand is WHY would companies try to purposely design engines that *have* to use Nitro (or at least too much nitro)? I mean, all it takes (in theory) to use less Nitro (or no nitro at all) is that the compression ratio needs to be slightly higher (like the Rossi engines).

One reason I can think of is that companies simply make more money selling Nitro Fuel. This can be a good corporate reason for pushing high-nitro engines). I guess that another reason is that people like smaller engines producing much larger amounts of power - though a simple increase in displacement would serve the same purpose while being a lot more economical (and less of a pain in the butt) to run!

I do find it a little whacky that a ROSSI 45 will not accept more than 5% nitro, while other two-strokes (such as the OS 46 AX) will gladly accept higher Nitro (15% or even more). I there a technical reason for this or is it a pure builder choice?

Thanks,

Atul

downunder

There's a couple of reasons but for sport engines the manufacturers quickly found out that Americans have a love affair with nitro because it's far cheaper in America than anywhere else in the world. The early Saito is a good example. At first they had very high compression and the instructions specified zero nitro fuel. When Americans started complaining that they were blowing up on 15% nitro the manufacturers decided to give in and lowered the compression to stop the complaints. Obviously the manuals don't get read . Another example is the big Moki where the American importer had to ask the factory to make a special low compression head for the American market because once again they were using too much nitro. European made engines though tend to make theirs more for the European market so have higher compressions for low nitro fuels.

For competition engines though it's a bit different because generally that's all about getting the maximum possible power and it's undeniable that nitro adds power so compressions are designed to suit.

atul

Ah! This now makes total sense. The 2-strokes (Jett, OS) work on zero nitro, though the OS runs better with 10% or 15% nitro. I have heard that the YS engines do like a lot of nitro (15% or more). Since Nitro costs $50/LITRE (i.e. $200/gallon) here in India, I can get a whole new YS every 7 gallons (about 60 flights). I guess it's worth using the brand new YS 110 on zero nitro for starters. Should be fun. I'll let everyone know how it goes. The YS guys will yell bloody murder - they consider YS to be a sort of sacred thing :-).

atul

Car-Tune

That was Funny!

atul

[quote]ORIGINAL: C-Los

That was Funny!
[/quote

:-). To add to the amusement, I have just learned the local government here in Bangalore has banned the sale of "pure methanol" because illicit distilleries were using Methanol instead of Ethanol in the manufacture or local booze. As a result, over 200 people died about 4 weeks back and therefore one can now only get Methanol that's mixed with 10% castor. This, of course, creates another headache for the "YS Crowd" who consider it heresy to use more than 2% Castor. The search is therefore now on to find "pure Methanol" - Life in India is one continuous drama.

Fortunately, I travel globally about 50% of my time, so I bring back all the needed parts, including Synthetic Oil. A week back I was in Istanbul where the baggage scan resulted in the inspector doing a major analysis for 15 mins on two bottles of MORGAN 100% Synthetic Oil :-). I guess they simply could not fathom why on earth someone would carry this stuff across 5 countries!

I brought back the YS 110 this weekend and I must say it is indeed a beautiful engine. No wonder the YS-Crowd is so protective of it :-).

The search is now on for 100% Methanol. If I cant find it I plan to use 10% Castor and 12% Synthetic to create a 22% Oil and 78% Methanol mix. I'll do the test later this week - should be interesting :-).

Atul

wjvail

My Feedback: (3)

All of what downunder commented on is completely correct.

I would add that there is a marked improvement in "needleablity" and throttle response with added nitro. With increased nitro, to a point, the engine becomes easier to tune. Where an engine might run well within a 2 or 3 "click" needle range on 80/20, it may now run acceptably in a 6 or 8 click range with 15% nitro (these are just contrived numbers to help define "needleablity" ). Engine manufactures want ham-fisted, tin-eared modelers to be able to fly/race too, and one way to help them is to design an engine to run on 15% nitro. While engines do run and can be made to run very well on FAI fuel (80/20%), they require more skill to tune and set up. Without the heat of Nitro and the with 1 part in 5 fouling the combustion process (the oil), engine tuning becomes more important.

Bill

JB COMP

What's funny? since you are replying to one of my post?

atul

[/quote]

All of what downunder commented on is completely correct.

I would add that there is a marked improvement in "needleablity" and throttle response with added nitro. With increased nitro, to a point, the engine becomes easier to tune. Where an engine might run well within a 2 or 3 "click" needle range on 80/20, it may now run acceptably in a 6 or 8 click range with 15% nitro (these are just contrived numbers to help define "needleablity" ). Engine manufactures want ham-fisted, tin-eared modelers to be able to fly/race too, and one way to help them is to design an engine to run on 15% nitro. While engines do run and can be made to run very well on FAI fuel (80/20%), they require more skill to tune and set up. Without the heat of Nitro and the with 1 part in 5 fouling the combustion process (the oil), engine tuning becomes more important.

Bill
[/quote]

Good point. I did experiment for fun with an OS 46 AX with 15% nitro and the engine did run smoother, showed a greater "Click range" and turned about 700 RPM more than with no nitro on the same prop (14,700 vs. 14,000 on a 10x6 prop). I suspect that the YS will be a lot more difficult to set on zero nitro since it seems to be designed for 15% to 30% nitro. It's already a sensitive engine so it remains to be seen how it works with the leaner mixture with zero Nitro. Clearly, with less fuel being burned the power will be lower and one cannot spin the same sized prop as one can with more nitro, but that's not a problem in my case. The plan is to simply build a slightly smaller plane!

atul

The Winner

hey guys i am between of two fuels the byron premium competition 25% with 16% oil and the byron gen2 25% with 11% oil! which it will perform the best without damage the engine??? i am a basher and racer . I bash with a monster truck(kyosho and lrp engine) and i race with st-rr kyosho .Maybe to buy the premium competition for my bash truck and the gen 2 for my race truggy!

downunder

The reason an engine has a wider range of "needleability" with nitro goes back to what I was saying in post #35 about air/fuel ratios. Methanol has an acceptable range of roughly 6.5:1 to 4.5:1 so call it about a 44% tolerance. Nitro though ranges from 2.5:1 to 0.5:1 or even richer so that's at least a 500% tolerance. With a blend the tolerance is somewhere between that 44% and 500+%.

Power doesn't drop just because there's less fuel being burned though with straight methanol. Methanol is quite a good fuel but nitro is a very bad fuel. The extra power from nitro comes from the fact that you burn so much of it each time.

atul

Hi All:

Here are the results of running a brand new YS-110 on FAI fuel (the recommended YS fuel is between 15% and 30% nitro).

The Engine was brand new. A beautiful piece of engineering one must say.

On straight fuel (FAI: 78% Methanol, 10% castor, 12% synthetic), the result were as follows (with a 15x6 prop to run-in)

engine started on the first flick : no problems

took it up to 4,000 RPM and ran it for 2 mins; no problems

maxed out the throttle for 10 secs : great transition; set high-speed needle to 1 1/3 turns (up from 1;25 to 1.33 basicallhy); came back to 4000 RPM (apparently this is recommended by YS Experts). At this point, the engine started LOADING UP.

Closed the regulator 1/8 turn; marked improvement in transition; took engine up to max RPM (about 9500); came back down; much LESS loading up now

Closed the regulator another 1/8 turn; this time, the transition was even better and on coming back to 4,000 RPM, there was no more loading up!

Started setting the idle: about 2100 RPM. Engine started loading up, Leaned out low-speed needle the idle was too rich, so had to lean it out by a 1/4 turn

Result: the engine continued to run well. Ran a 12 oz tank for about 11 mins. Not bad! With ZERO nitro, the engine runs well enough. with Nitro, the engine will likely run smoother and one can likely get 400 to 500 RPM more and turn a bigger prop. But that's not my goal. The goal is to enjoy the YS power with 500 less RPM on a smaller model!

Cleanup: stopped engine after 2 tanks (had to run errands after that), and had a helper remove the blue tubing and clean out the engine (to prevent Castor Oil gunk from clogging the engine), with Kerosene.

Conclusion: YS Engines run great on no nitro. Just follow Troy's run-in instructions and you can't go wrong.

Next steps: practice a lot of flying on the 69" Yak and then graduate to a 170 DIngo with NO NITRO :-).

atul

downunder

atul
Well done and I think you're probably the first one to try running a YS on zero nitro . I'd suggest starting a thread on it in the [link=http://www.rcuniverse.com/forum/forumid_114/tt.htm]Glow Engines[/link] forum though because there's some worry in there as to if a YS will run on zero nitro due to the shortage. But I think you've proved that if a YS will run ok then any engine will.

atul

Downunder: I was encouraged by the information you provided about Nitro (that it basically helps pump more fuel into the engine per stroke and that's where the power and needleability comes from). This was borne out by the fact that the 0-nitro fuel required a far leaner mixture. The first run also used 22% oil (10% castor and 12% synthetic) to keep the oil flow rate the same as when one uses higher nitro. All that helped I guess.

Note however that it's only been 2 tanks for now (haven't found the time to run it more - will do next week), and that the engine has not been in the air yet. So the experiment is far from finished.

Apparently, cleaning the engine with Kerosene was a bad idea since the YS has many internal Silicone parts as well - so I'll be using pure Alochol (hopefully I'll find it!) for cleaning in future, until I can figure out where to get pure nitro and move to a 20% synthetic Oil and 2% castor mix, which should eliminate the cleaning process altogether. Do you have any idea of an alternative to Kerosene for cleaning the engine: can I 'clean up' the carbon deposits left by Castor by using FAI Fuel that has some castor (10%)? Since the 'cleaning fuel' is not burning, I suspect it cannot leave "black deposits" (which seems to make the YS purists a little mad each time they hear about Castor :-).

I'll start the thread on the Glow-Engines forum as well.

BTW - I've always normally run Zero Nitro on all my engines: Rossi, JETT and now YS. It seems on the face of it that the most important thing for longevity of an engine is running enough oil to prevent a lean run, and not more Nitro to make the mixture richer....

Atul

downunder

It's generally accepted that a mix of synthetic and castor is all that's needed to keep any carbon deposits down. A friend of mine runs his Saitos on zero nitro (with much raised compression though) and uses castor with a little synthetic (90/10 castor/synthetic) to keep it clean inside. Washing the castor out of the crankcase isn't a good idea though because it's an excellent rust preservative (after run oil if you like) and it takes a very long time for it to start getting sticky, many months.

atul

All right! This is excellent advise indeed: I can then simply stick to the 80/10/10 mix (methanol/castor/synthetic) and the engine should be just fine without having to flush things out.

The next step (after some more experimentation) should be to figure out a way to increase the compression of the YS engine. That should put the power back up to where it needs to be and the overall operation will be economical too.

Thanks!

Atul