Alternative smoke oil?

[ChrisPilot]

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

[FlyingRon]

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.

[1600vw]

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

[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.

[1600vw]

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

[FlyingRon]

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.

[ChrisPilot]

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 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?

[WLIU]

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

[JimRice85]

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

[1600vw]

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