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Author Topic: Fuel  (Read 977 times)

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Offline Deerslayer

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Fuel
« on: February 20, 2011, 08:58:16 AM »
Here is my attempt to re-open the age old controversy: castor oil or no castor oil!

Oil choice is in the realm of religion - it's all a matter of opinion, but my view is the only one that is correct. Anyone who has owned motorcycles and checked into the forums will see the endless "oil wars" up close!

OK, I am  not really trying to start a fight. Besides, it seems like we "slimer drivers" are reducing as a percentage of the overall r/c powered aircraft community and the older ones have already made up their minds. However, in case there are folks starting out, here is what I have experienced in over 20 years of using "synthetic" rather than castor oil blend fuels.

I have been using Cool Power, the same regular sport fuel with 15% nitro, on engines from .15 up through 1.20, both 2-stroke and 4-stroke. IT has worked well for me, after being the first "synthetic" I tried, and I just never felt the need to experiment further  A lot of engines, a lot of use, some from right out of the box, others purchased after various stages of use/misuse. One helicopter, with a SuperTigre .34 that just would not run reliably, immediately transformed into rock solid reliability when we changed to this fuel and a different plug type.

The ONLY bearings I have ever changed are: one set in a Saito .56 which I bought new and put through a lot of use for a couple of years and which made a lot of rumbling noises before it eventually ate a bearing; a couple of engines which I purchased used and were gummed up almost solid with the castor residue. One of the latter was formerly owned by my much older and more experienced friend (remains nameless here) who steadfastly maintained that you absolutely had to have castor in your fuel. Others will say that if you ever get a "lean run", through deliberate or accidental overly lean mixture, only castor will save you. Well, I have had that happen, too, and with no obvious detriment to my engines.

A couple of used engines that I have looked like they had hardly been used, yet when I popped them open, the bottom end and bearing areas were almost solid with castor crud. Sometimes, I would almost have to chisel and blow torch the carb throttle body to get it free to move.

I never use after-run oil, except in the case where I remove an engine from an airplane, knowing that it will be stored for quite awhile. Then, I may squirt some 3-in-one, some ATF, or better still, some Mobil 1 synthetic 10W40 motorcycle oil that I happen to have handy. Otherwise, the plane is either sitting horizontally, or preferably hanging from its prop. Some have hung for as long as 3 years, been dragged out to the field and started on the first or second try. Usually, some nasty- looking crap comes out of the exhaust at first and then it is clean and clear. That would be any crud or corruption that had collected in the lower or rear of the crankcase - and therefore NOT in around the bearings.

So-called synthetic oils (there is a name that gets badly abused by manufacturers for marketing purposes) have 3 very admirable qualities, all of which are important to me. They really cling well to the steel parts of the engine. They withstand very high temperatures (if you delve into the science, you will find that they maintain film strength at much higher temperatures than do vegetable oils - like those from the castor bean - or the so-call "dino" oils. And, finally, they maintain their viscosity grade over very wide temperature ranges, including toward the lower end of their design range.

Our model oil does not have to last long - apart from the film left coating the bearings or sleeves during storage, the rest of it is flushed through the engine in milliseconds.

I have rarely ever changed a glow plug in 20 years! Prior to my conversion, I used to be frequently changing crudded and unreliable plugs fairy frequently.


Remember, the non-vegetable oils you buy today bear little resemblance to what was manufactured 10 years ago. That is one area where technology has made giant leaps forward. Do not compare things as they were in the gold old days.

OK, bring it on!
My purpose in Life is to serve as a Warning to others