Hi guys,

Just a few questions, was having some great fun smoking the field out today with my nitro Truggy.

What actually creates the smoke? I've read that it's just vaporised oil? If so what oil would that be, synthetic or castor, or both? Is it really just oil because it doesn't smell the same as the stuff you put in .

Thanks!

vaporized oil or oil burnt with too much air will produce white smoke. Burning oil with too little air will produce black smoke.

Sorry I should have mentioned, it's with nitro/methanol fuel and the smoke is blue.

Thanks for your post.

Anyone else? Thanks.

Unburnt fuel and oil. Smoke is good because it carries some of the heat out of your engine.

Err... it really isn't the oil that makes the smoke. Most of it is water vapor. Clearly unburnt oil is part of it but it is the water vapor most people notice.

In this thread [link]http://helifreak.com/showthread.php?t=56130&highlight=bill+smoke&page=2[/link], I weighed in on post #11. Heli's appear to smoke more but run about the same amount of oil. They just hold the exhaust longer in larger mufflers. This allows the exhaust to cool more and the water vapor to condense more. Here is a repeat of the vid posted in the other thread. http://www.youtube.com/watch?v=20sI4h3I950 What you see in this video as exhaust is all water vapor.

Collect your exhaust and you will find there is 3 times more water than oil.

Bill

I doubt it is mostly water vapor. An engine running lean puts out just as much water vapor but much less smoke. If you want to see some smoke, watch a control line Fox stunt 35 running along on 28% castor oil.

smokin rich, all synthetic, but happy, happy, happy...

Well, it 100% changes for sure with weather conditions. At first I thought it was humidity but when I go out and it's 98% humidity there can be little smoke some days and a lot others.

Today, it was fog, and the engine smoked a lot (great fun! ), even though they say the humidity was 84%.

Smoke is defined as particulate matter, suspended in gas.

It is very small solid, or liquid particles; such as ash from the different oils burnt in the engine and unburnt carbon, or unburnt liquid matter.

All fuel enters the engine in a liquid state and most of it becomes gaseous, before and during combustion.

But all combustibles must break-up into their elements before combustion and carbon has a much higher propensity to remain unburnt and thus leave the engine in its solid form, hence particulates - smoke.

And as to smoke emitted intentionally; it is particles of ash from burning and evaporation of special, low-viscosity oil, such as Chevron/Texaco "Canopus 13".

Water vapor, or fuel vapors are not smoke.

Under normal operating conditions, castor oil doesn't burn. So I suppose it comes out as tiny droplets or particles.

What makes you think it doesn't burn?

Remember that the temperature of the combustion gases is *much* higher than the temperature of the engine that contains them.

The combustion-gas temperatures will be around 1,750 degrees C, far hotter than that required to burn castor oil so any oil that's not actually in contact with the engine's piston/head/cylinder *will* burn.

The amount of castor oil I clean off my plane after a flight.

Its just vaperoized oil. When you put a smoke system on a plane you inject smoke oil and it makes smoke similar to the smoke of a glow engine but just a lot more of it.

condense it,collect it,find out

Not really, I just thought I asked a simple question which would have a simple answer seems like there isn't one.

It can't be just castor oil because helis run with no castor oil and some fuels pour out tons of smoke. Does the methanol contribute anything to the "smoke"?