Engine & Boat Tuning for Methanol

[AndyBrown]

Looks like I got one at least partially right, reduced chamber volume...................
My thought was the leaner mixture is less mass to be compressed. After all, nitromethan is only liquid oxygen; but since it is a liquid, it is volume and mass in the chamber. Thus less chamber volume is appropriate.

Well Jon, maybe we are both wrong. There is a world full of very experienced 80/20 racers. Maybe they have a different opinion.

 

[John Knight]

Bravo to Andy for answering the questions and giving his honest opinion. Now we have some idea where to start and go with things. I know his caution about giving out detailed info because it will not always work due to the variables with each racer and his situation. No cookie cutter formula that fits all.

Thanks much and I am certain I speak for all of us.

 

[hydro]

I am all for running 80/20 methanol or even low nitro if it is not to pricey in the future and have had good results with the airplane fuel of 5 to 15 % One question, What additives can we use with methanol to enhance its energy output that are cost effective...... Like propylene oxide ?? anything else ??

John

 

[AndyBrown]

I am all for running 80/20 methanol or even low nitro if it is not to pricey in the future and have had good results with the airplane fuel of 5 to 15 % One question, What additives can we use with methanol to enhance its energy output that are cost effective...... Like propylene oxide ?? anything else ??

John

Nitro! LOL

Propylene oxide makes my head spin...I never use it, not even with 80% nirto. I run the other way when Terry Keely and others who use the stuff are running their boats at Record trials.

Keep it simple.

 

[Tim_Duggan]

Acetone?

http://www.turbofast.com.au/racefuel.html

 

[DaveMarles]

If anyone is interested these are results of bench testing a .90 years ago on a fixed load when we were about to move from no nitro to being allowed to use nitro. Exhaust gas temperature is the interesting one. These tests were taken after optimising head and pipe length as much as possible.

RPM EGT (degrees C)

80/20 meth/castor 18200 430

80/20 meth/synthetic 18100 455

15% oil mix 20% nitro 19500 387

15% oil mix 5% nitro 18800 405

10% castor 20% nitro 19200 363

Dave

 

[Tim_Duggan]

Thanks Mr Marles - very informative!

I'm probably asking too much, but do you happen to have the MSV data for each of the "optimised" heads by any chance?

 

[DaveMarles]

Tim, No MSV figures. These settings were optimised by trial an error back in about 1984/5.

MSV figures are not easy to calculate on model engines and although I can do it and do sometimes on a particularly good engine, its not top of my list of things to do. You can ask 5 people to measure an engine for MSV and you would probably get 5 different answers. I'm sure someone might disagree with that statement but hey ho, I'm just a boatracer, what do I know.

 

[AndyBrown]

Dave,

Were those tests completed on 1984 CMB or OPS 90's?

What was the Trapped CR?

Squish clearance?

Stinger diameter?

Basic combustion chamber shape?

 

[hydro]

Here's some very interesting info

http://www.turbofast.com.au/racefuel15.html

 

[Jerry Wyss]

Thats pretty revealing,, Conservative Maximum C/R for "Nitro" 6.5:1 and 10:1 with rich mixtures, is what most of us have been doing.

Same for "Methanol", 17:1 Max C/R!!! Thats a surprise to this boy

 

[Jerry Wyss]

Dave,Were those tests completed on 1984 CMB or OPS 90's?

What was the Trapped CR?

Squish clearance?

Stinger diameter?

Basic combustion chamber shape?

Ha, Now look at these questions!

 

[TomMoorehouse]

nitrobenzene! what other good chemicals can we burn?

 

[Bob Finn]

Thats pretty revealing,, Conservative Maximum C/R for "Nitro" 6.5:1 and 10:1 with rich mixtures, is what most of us have been doing.
Same for Methanol, 17:1 Max C/R!!! Thats a surprise to this boy

From back in my U-control speed days, I can pass a little info. There was an FAI class that we ran .15 sized tuned pipe engines. The cylinder timing numbers were somewhat different (120 - 160) , and very high compression head buttons. We ran considerably smaller blade area props, and the idea was to let the motors turn up extremely high RPM. Surprising how fast the little motors ran.

A few years ago ( 1990's), our club had a club race with special rules. FAI fuel from the club jug(80-20synthetic), and everybody ran their 20 monos. I think we ran about 18 boats that day and about 8 rounds. It was really a lot of fun. I remember running a Picco P5 .21, and I made a really high compression button for it. Went down a couple sizes on prop. It ran really well. Obviously not as fast as nitro, but still was a lot of fun and very competitive. In my opinion, the exhaust timing in most of the newer motors is a bit too high for alcohol, and the head buttons would be the other issue. I'm sure the Italians can come up with the needed changes, since they run very little nitro over there.

 

[Jerry Wyss]

Those 120-160 timing figures are what alot of the buggy engines are timed for, the XM and the newer Rossi AXE is right there as well. I hate to relearn this stuff all over again,, I just got to where i could make most anything roll with high nitro.

Thanks for that info Bob.

JW

 

[AndyBrown]

Thats pretty revealing,, Conservative Maximum C/R for "Nitro" 6.5:1 and 10:1 with rich mixtures, is what most of us have been doing.
Same for Methanol, 17:1 Max C/R!!! Thats a surprise to this boy

From back in my U-control speed days, I can pass a little info. There was an FAI class that we ran .15 sized tuned pipe engines. The cylinder timing numbers were somewhat different (120 - 160) , and very high compression head buttons. We ran considerably smaller blade area props, and the idea was to let the motors turn up extremely high RPM. Surprising how fast the little motors ran.

A few years ago ( 1990's), our club had a club race with special rules. FAI fuel from the club jug(80-20synthetic), and everybody ran their 20 monos. I think we ran about 18 boats that day and about 8 rounds. It was really a lot of fun. I remember running a Picco P5 .21, and I made a really high compression button for it. Went down a couple sizes on prop. It ran really well. Obviously not as fast as nitro, but still was a lot of fun and very competitive. In my opinion, the exhaust timing in most of the newer motors is a bit too high for alcohol, and the head buttons would be the other issue. I'm sure the Italians can come up with the needed changes, since they run very little nitro over there.

"It was really a lot of fun. "

Amazing!

Thanks for this post Bob!

 

[Bob Finn]

Thats pretty revealing,, Conservative Maximum C/R for "Nitro" 6.5:1 and 10:1 with rich mixtures, is what most of us have been doing.
Same for Methanol, 17:1 Max C/R!!! Thats a surprise to this boy

From back in my U-control speed days, I can pass a little info. There was an FAI class that we ran .15 sized tuned pipe engines. The cylinder timing numbers were somewhat different (120 - 160) , and very high compression head buttons. We ran considerably smaller blade area props, and the idea was to let the motors turn up extremely high RPM. Surprising how fast the little motors ran.

A few years ago ( 1990's), our club had a club race with special rules. FAI fuel from the club jug(80-20synthetic), and everybody ran their 20 monos. I think we ran about 18 boats that day and about 8 rounds. It was really a lot of fun. I remember running a Picco P5 .21, and I made a really high compression button for it. Went down a couple sizes on prop. It ran really well. Obviously not as fast as nitro, but still was a lot of fun and very competitive. In my opinion, the exhaust timing in most of the newer motors is a bit too high for alcohol, and the head buttons would be the other issue. I'm sure the Italians can come up with the needed changes, since they run very little nitro over there.

"It was really a lot of fun. "

Amazing!

Thanks for this post Bob!

Oh man, I just read back in the post and saw Nitrobenzene mentioned. We all quit that stuff 25-30 years ago after Bill Wisniewski got the poisoning from it. Bad stuff! I'm thinking that all of the nitrated hydrocarbons will get very expensive and hard to come by like Nitro. Lets see, nitroethane, nitropropane, nitropentane, nitrotoluene, etc. And then there are some ethers and hexanes, amyl acetate, hydrozene, acetone, MEK, etc,etc. Keep it simple. FAI fuel will work, and with a few changes these motors will run very well. Racing is racing. They will just be a slight bit slower and easier for us old guys to drive!!!!

 

[DaveMarles]

Dave,Were those tests completed on 1984 CMB or OPS 90's?

What was the Trapped CR?

Squish clearance?

Stinger diameter?

Basic combustion chamber shape?

Andy, CMB 90 and I don't have the other figures, too far back in time and my archives.

Dave

 

[dave roach]

Back about 15 years ago when the nitro factory down south went up in flames the only people getting nitro was the top fuel guys and at that time. I ran 60% actone,alc,and klotz oil and did"nt see any differance on the way the boat ran.So if we are going to see a nitro shortage looks like going back to the back up plain.

Dave Roach

 

[Tim_Duggan]

Borrowed from the site I posted a link to earlier.

"EASIER STARTING ADDITIVES - WHEN USING METHANOL .

 

Acetone is the only additive and up to 10 percent maximum. The action of this is to increase the volatility of the total fuel or put another way it reduces the flash point temperature.

 

Main use is on very cold days, but in fact it even then should not be really necessary, however let us say it is convenient. "

I have also read on another r/c site that adding 5-10% acetone to methanol / oil fuel makes the needle considerably easier to find. I believe this might relate to one of the concerns listed earlier on in this thread with regards to burning up engines.