quote:

The only engines I know that do not like nitro above 30% are the Saitos.

quote:

ORIGINAL: loughbd

Well boys,

I just got done with 3 hours of fooling around with Saito four cycle glow engines. I ran a little experiment on the differences of high and low nitromethane content fuel. Here's today's results. I had to quit after the first two engines as my neighbor was complaining about the noise (from a small 4 cycle?). I'll do the Saito 50 tomorrow.

I ran two engines in todays effort. The first was an OLD bolt on head Saito FA45. The second was the more modern one piece cylinder and head Saito FA45. Prop was a TF power Point 11x6. Fuel was Hobby Shack White Lightning (10% nitromethane, 20% castor oil, 70% methanol. The other fuel was Cox Red Can racing fuel (35% nitromethane, 20% castor oil, 45% methanol. The fuel was measured with a monoject 2 ounce syringe. Glow plug was an Enya #3, the plugs I use in most of my engines.

Now from what I read in this thread I should have seen a large increase in power with the 35% stuff. Also as one member stated the fuel consumption on the 35% should have 2 1/2 times as much. I ran each engine a short time to get the best needle setting then ran each engine 4 times and took the avarage time each ran on two ounces of fuel and the average RPM I got using a Royal products tachometer.

I tried the old bolt on Saito first. On the 10% fuel it ran about 8900 RPM and about 7 minutes on two ounces. I couldn't get it to run worth a poop on the 35%. It got hot and kept quitting. I opened the needle until it would run without overheating and quitting and it ran so slow it wouldn't have been useful as an engine. Gave up on it.

Here are my results with the newer one piece saito 45.

On the 10% fuel the average RPM was 10,000 and it ran an average of 5 minutes and 20 seconds on two ounces of fuel. That's for four runs and I left the hatch open to make sure all the fuel was used.

On the Cox 35% nitro fuel the average RPM was 10,200, a gain of 200RPM. The average run time was 5 minutes and 5 seconds. A difference of about 15 seconds for 2 ounces of fuel. Probably a negligable amount as far as flyng time is concerned.

The price of a gallon of 10% nitro Powermaster fuel is about $13.00 here where I live. A gallon of Cox fuel runs about $110.00 per gallon. A gallon of Cool power 30% heli fuel from Tower is $23.00 plus a bunch for shipping.

The net difference between 10% nitro and 35% nitro in my little experiment was about 200 RPM and the run time was almost identical. Do I think it's worth the difference?? NOPE.

You can believe what I say and did or can say I'm full of you-know-what but you are all free to do the same thing I did.

Tomorrow I am going to run the Saito FA50 on my Skyloop 404 and see what the results are.

One surprising thing to note was the difference in power the newer one piece saito had over the older bolt on head Saito. Both are well broken in and the newer one probably has more time on it. Both have excellent compression and new or good bearings.

quote:

ORIGINAL: loughbd

Castor oil is a well known problem in higher nitro fuels???? Since when? Fox Blast was 50% nitro and 20% castor oil. Cox fuels were 25% and 35% nitro and all castor fuels. In the days before synthetics all fuel was castor lubed and we ran as much as 70% nitro in C/L racing engines with no problems other blown plugs and busted rods.

You want a comparison using a castor synthetic mix?? I can do that to0. I don't have an OS 70 that I want to run but I have 90's 40's 26's 60's 61's 120's 120 twins. What would you like?????

There won't be any difference just like there weren't with the saitos but I guess seeing is believing.

"The only engines that don't like nitro over 30% are Saitos"??? My 45 didn't care one way or another about using 35% nitro fuel. There was NO difference.

I knew someone would find fault in what I did.

quote:

[/we ran as much as 70% nitro in C/L racing engines with no problems other blown plugs and busted rods.
quote]



I GET A KICK OUT OF HIGH NITRO USERS ALWAYS SAYING WITH NO PROBLEMS..........
I WOULD CONSIDER A BUSTED ROD MAJOR PROBLEM AND BLOWN PLUGS IS A UNPLANNED DEAD STICK EVERY TIME.

< Message edited by speedster 1919 -- 9/16/2006 2:42:17 PM >

_____________________________

Hey Buddy -That was the most spectacular crash I've ever seen , That rolling cart wheel with parts slinging out was cool...

(in reply to loughbd)

quote:

The net difference between 10% nitro and 35% nitro in my little experiment was about 200 RPM and the run time was almost identical. Do I think it's worth the difference?? NOPE.

quote:

ORIGINAL: loughbd

Dar, I have used an OS type "F" and I have used a Saito P-2 and several other plugs. There is, for all intents and purposes, NO difference.

I fly scale models and you don't need brute power to compete in a scale contest. As a matter of fact you will get downgraded in the flight realism category if you fly around at full speed. Very few four cycle engines are used in racing events.

quote:

ORIGINAL: loughbd

Castor oil is a well known problem in higher nitro fuels???? Since when? Fox Blast was 50% nitro and 20% castor oil. Cox fuels were 25% and 35% nitro and all castor fuels. In the days before synthetics all fuel was castor lubed and we ran as much as 70% nitro in C/L racing engines with no problems other blown plugs and busted rods.

You want a comparison using a castor synthetic mix?? I can do that to0. I don't have an OS 70 that I want to run but I have 90's 40's 26's 60's 61's 120's 120 twins. What would you like?????

There won't be any difference just like there weren't with the saitos but I guess seeing is believing.

"The only engines that don't like nitro over 30% are Saitos"??? My 45 didn't care one way or another about using 35% nitro fuel. There was NO difference.

I knew someone would find fault in what I did.

quote:

ORIGINAL: loughbd

Castor oil is a well known problem in higher nitro fuels???? Since when? Fox Blast was 50% nitro and 20% castor oil. Cox fuels were 25% and 35% nitro and all castor fuels. In the days before synthetics all fuel was castor lubed and we ran as much as 70% nitro in C/L racing engines with no problems other blown plugs and busted rods.

You want a comparison using a castor synthetic mix?? I can do that to0. I don't have an OS 70 that I want to run but I have 90's 40's 26's 60's 61's 120's 120 twins. What would you like?????

There won't be any difference just like there weren't with the saitos but I guess seeing is believing.

"The only engines that don't like nitro over 30% are Saitos"??? My 45 didn't care one way or another about using 35% nitro fuel. There was NO difference.

I knew someone would find fault in what I did.

quote:

ORIGINAL: loughbd

Didn't bother. I knew someone would contest my findings or say that with some other brand "Z" fuel or brand "X" plug eveything would be different so I just said to heck with it. I know what I know and what I have been doing for over 45 years. I mean when some guy says one plug will make as much as a 1000 rpm difference I figured it wasn't worth the effort.