Alternative smoke oil?

Hi

I have noticed that commercial smoke machines used in the entertainment industry etc. are using a "smoke liquid" based on glycol rather than based on mineral oil. Also in the RC community some seem to use glycol/water mix as alternative to various oil based mixtures. Glycol is probably also safer from a health perspective both for the pilot and the audience, and the flash point is also in the same order of magnitude. So are there any drawbacks, and what about compatibility with aircraft paint and gelcoat?

Any experience out there regarding glycol based smoke liquids for full scale aerobatic planes?

Fly safely

You need to be very careful with atomizing glycol at high temperatures. It can make a lot of nasty formaldehydes. Even those of us using it for stage smoke have to watch it when it would otherwise be considered safe.

Ron what type of oil do they use on a stage?

It's propylene glycol, but you've got to be very careful not to run the heater to high. If it starts to smell funny, you have it too hot and it's generating bad stuff.

I thought about adding a smoke system to my little airplane. Not for aerobatics but for practicing things like steep turns and s-turns over a road and for turns around a point one could keep their eyes outside the cockpit and tell if they are loosing or gaining altitude without ever looking at a gauge in the cockpit.

Tony

Umm...an altimeter would be cheaper and more accurate. You do understand that smoke settles and moves due to the wind? Your manouvers are supposed to be done to adjust for the wind so that your ground track is consistent.

The smoke oil kit people call it a VISUAL COLLISION AVOIDANCE SYSTEM if you want an excuse.

Most casual smoke system users find that the smoke comes in through every crack in the belly to create IFR in the cockpit. The airflow across the top of the airplane creates low pressure that pulls exhaust and smoke in through belly openings as far aft as the tailwheel. You have to seal every possible opening. Most non-airshow folks use the smoke system a couple of times and then it becomes dead weight.

Canopus oil, formerly Corvus oil, comes in 55 gallon drums and costs $400+. At the airshows we get it for free, but most civilians don't want that expense. The good substitutes for Canopus are even more expensive.

Its less cool in practice than it is in theory unless someone is providing it for free and paying you to use it. It does enhance an airshow performance.

Best of luck,

Wes
N78PS

You can buy it in gallon jugs for around $25/gal.

To put that in perspective, to get really good smoke you want to flow at least 1, and generally more like 2 gallons per minute.....

Best of luck,

Wes
N78PS

Yep, it's not cheap. Even by the barrel you're paying for the fun. Also note that the size of a smoke tank in most small aircraft installation is measured in minutes you can count on with your fingers.

It also frequently leaves an oily mess on the airplane which needs wiped off.

Learned alot from this thread. As for the altimeter I do have one but like to keep my eyes outside the cockpit. For wind, I never fly when there is wind above 6 mph. My airplane has such low wing loading it's just no fun when its windy or thermals are out. Early morning or late evening is my type of flying.

Tony

And then there's the Pietenpol crowd, who've smoked for years! A couple of them use pump-up jugs (garden bug sprayers) sitting on the seat next to them. I myself have never partaken, just reporting what I've seen for several years at the Brodhead Pietnepol fly-in.

The Piet builders are creative folks. I wonder if they do morse code messages with their pumps and smoke.

Best of luck,

Wes
N78PS

Quote:

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Originally Posted by WLIU

The Piet builders are creative folks. I wonder if they do morse code messages with their pumps and smoke.

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"CURSE....YOU....RED....BARON" :-)

Ron Wanttaja

Quote:

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Originally Posted by FlyingRon

It's propylene glycol, but you've got to be very careful not to run the heater to high. If it starts to smell funny, you have it too hot and it's generating bad stuff.

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I believe that the heating element in stage type smoke machines operate well above 500F, while EGT of aerobatic airplanes is more in the range 350-400F. The question then is if it is too cold for proper atomizing of glycols, while smoke oils perform better?

My Exhaust Gas Temp gauge reads 1500F 4" down the exhaust stack from the cylinder. A few inches farther down where the smoke oil fittings are I doubt the gas has cooled below 1000F.

Best of luck,

Wes
N78PS

Correct me if I'm wrong, but don't some use transmission fluid as a cheaper alternative? I've even hard that used, dirty (free) fluid smokes best.

ATF makes nice white smoke but the cost is higher not lower. You also might need to thin it a little with diesel. I will suggest that dirty fluid might clog your nozzles and make wiping the belly down even more annoying.

Best of luck,

Wes

Corvus oil wasn't designed for smoke systems. It's a light oil used for both wood preserving and as a release agent (to keep concrete and stuff from sticking to the forms/molds). Some other release agent oils are easier to come by in smaller quantities and those are often used.

The VansAirForce guys have tons of articles on smoke systems. It's not all that involved if you're in an experimental. My friend made his own tank for a starduster. A small electric pump and a nozzle inserted in the exhause will work. There are some commercial systems that have had field approvals for certificated aircraft.