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Home✈️Aircraft🚁HelicopterGasser Model RC HelicoptersEngines › Changing oils change settings?
06-06-2015 04:33 PM  4 years ago
mcfast

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Quebec Quebec Canada

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Marine oils is not made for air cool motors, its not even made for a normal water cool motors like a 2 stroke motorcycle motors, it is made for a marine motor that runs in a lake, witch does not even get warm, that is why a
semi-synthetic oil for a air cool motor is more then enough and cost lees then a full synthetic marine oil, like a guy toll me you can insult a guys wife but do not insult his oil, LOL
P.S. sorry for the spelling or the grammar I am dyslexic!
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06-06-2015 11:06 PM  4 years ago
fastflyer20

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N. Tonawanda, NY

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mcfast - no question syn oil, including Pennzoil marine full syn, offers superior lubrication to petroleum oils. Rip apart enough engines and you will see. In fact, I have seen very little difference compared to some expensive oils.

There is a reason we call petroleum oil liquid sandpaper. But if you have good results in life and lack of carbon build up keep using it.
Tom
CAUTION - my posts are based on my experiences, yours may be different.
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06-06-2015 11:54 PM  4 years ago
turboomni

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East of the Equator

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Mcfast if you have had good luck with your oil that is great and you should continue using it. For me using what I use the extra expense compared to conventional oil is peanuts.Setup is everything, All my heli's can fly far better than I can pilot them
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06-07-2015 02:13 AM  4 years ago
sps3172

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St. Louis, MO

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...You may be correct mcfast but I would argue that these engines are not lightly loaded...That poor heli engine hovering around is constantly loaded...
When it comes to hover, a helicopter engine typically operates under a light load. This seems to defy 'common sense' especially when considering the engine temps generated in a helicopter application. The temps can usually be attributed to the cooling system...not excess loading.

Full loading occurs when climbing out, etc but when we pull the pitch out and power back, but still maintain the same RPM (as in hover), we do so because we have unloaded the engine.

Most of the SNAFU associated with getting an I/C engine to run 'smoothly' in a helicopter, when hovering, stems from the fact that the engine is lightly loaded in hover. The two main ways to combat this light load instability are with a richer mixture or reduced/retarded ignition timing.

In a glow/nitro engine, an overly rich mixture (they all 4 stroke in hover now days) and sometimes added oil content in the fuel (think CP 30%)serve to tame this light load instability.

I remember years ago when Chris Bergen first announced his success with Pennzoil Marine 'injector' variety oil. He noted that he could achieve smooth performance with a stock engine when everyone else needed modifications for smooth running zenoahs. I've always wondered if part of that oil's 'charm' was that it provided a slight reduction to the timing (slowed combustion...etc) to help tame the light load instability.
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06-07-2015 03:42 AM  4 years ago
turboomni

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East of the Equator

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When it comes to hover, a helicopter engine typically operates under a light load. This seems to defy 'common sense' especially when considering the engine temps generated in a helicopter application. The temps can usually be attributed to the cooling system...not excess loading.
I said constant loading not excess loading. Excess loading will make problems in any situation. I have an old Min Air 1005 with a very poor gear ratio of 6.43 to 1. The heli does not like anything much over 1800. It would be easy to excess load it at hover by simply run the engine too slow and add pitch,,lug the zenoah down till she burned up ..sure richen it up and see what happens.
I mentioned the cooling system not being in it's rpm range and then not be as effective as it could be.
Full loading occurs when climbing out, etc but when we pull the pitch out and power back, but still maintain the same RPM (as in hover), we do so because we have unloaded the engine.
Full loading yes is full climb out but as you know you have to find the correct pitch the engine can handle with the gear ratio and engine rpms and blades etc to prevent excess loading as you call it. Pull out the pitch and the engine gets a break with little loading and hopefully enough rpm's to cool her self down. Hopefully when returning to hover you have enough rpms and with it the fan is working in it's sweet spot to cover you. My point is too low an rpm with the load applied [pitch] will not work out well.

I remember Bergen recommended gassers with an oil mix in the low 20's and you maybe correct when you said
I've always wondered if part of that oil's 'charm' was that it provided a slight reduction to the timing (slowed combustion...etc) to help tame the light load instability.
It is possible because he always touted that his helicopters didn't require a balanced engine when using up to the 26cc at least.

My point is you can "excess load" an engine at any speed and overload easily if the conditions are right.
Setup is everything, All my heli's can fly far better than I can pilot them
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