OS 70 FS BLUE? SMOKE
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my os 70 fs has been a great engine for 2 years, turns 14x4w at just over 10k. hadn't flown for 2 months. flew 8 flights in the last two days, exhaust appears slightly blue, not the regular white color. i notice it on take off and low fly bys when i add power, it appears slightly blue. engine has (about) the same power it always has. is it the ring? same fuel, wildcat 15% nitro, 18% all synthetic oil.
jon b
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Smoke's color is affected by the light that is used to illuminate it. Perhaps the weather has changed in your area and the sunlight is a little different?
Blue smoke only comes from petroleum burning in fuel. My Diesels make lots of blue smoke before I get them running right. Model Diesel fuel contains kerosene (which usually makes white smoke) and oil that is compatible with kerosene. I'll bet the oil is where the blue smoke is coming from with my Diesels.
I wouldn't worry about it. You said the engine is running just fine, so I believe you. A worn ring in a model engine burning alcohol based fuel will not make blue smoke unless you are running some petroleum additives in the fuel in addition to the stock stuff.
Ed Cregger
Blue smoke only comes from petroleum burning in fuel. My Diesels make lots of blue smoke before I get them running right. Model Diesel fuel contains kerosene (which usually makes white smoke) and oil that is compatible with kerosene. I'll bet the oil is where the blue smoke is coming from with my Diesels.
I wouldn't worry about it. You said the engine is running just fine, so I believe you. A worn ring in a model engine burning alcohol based fuel will not make blue smoke unless you are running some petroleum additives in the fuel in addition to the stock stuff.
Ed Cregger
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you know what, i just got a new pair of rc fliers' sunglasses w/my prescription, they have a different color lense than i'm used to, and it has been very gray/overcast. i'll try sunday - clear sky w/clear glasses, just thought of that. blue does sound like a strange color exhaust for a glow fuel.
jon b
jon b
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ORIGINAL: jb86
...exhaust appears slightly blue, not the regular white color.
...exhaust appears slightly blue, not the regular white color.
And I guess it somehow reminds you of that old Chevy/Ford beater that you drove when you just got your driver's license...
The one that burnt a lot of motor-oil....
Well, all glow engine burn oil, but you don't need me to tell you this, do you?
And if that old car burnt 2 quarts of oil per 1,000 miles, or 300 quarts of fuel, it would be visible as blue smoke.
Your four-stroke burns a quart of oil per 4 quarts of flammable fuel components...
And yes, it can have a color of light pink, light yellow, light green and light blue, or just white.
It is affected by ambient light, but also by the dye the fuel maker uses in the oil, or the fuel.