Tried a smoke system on the falcon today, too windy to fly so just did a quick run, no electric pump, just an old retract phneumatic bottle and ordinary diesiel fuel from petrol station, air pressure @ 80 psi, 3mm RS brass tubing crushed down to @ -020 thou at the end, bottle held 125 ml run time @ 30 secs, will post more details later, no time now
I was concerned about any flame breaking past the turbine and setting light to the diesel being injected into the engine, during heavy accel from low power settings, so searched the web for info, but couldnt find any help. I did find a company who sell smoke systems and their own smoke fluid called MT smoke oil. This is completly non hazardous, but it does burn. As the weather was so bad the past couple of weeks, I thought I would try the smoke system on the ground, with the tail and booms missing and see if the fluid would catch fire during accels. The MT fluid produced good smoke and Did momentarily ignite during rapid accel. The extent of any flame could not be seen due to the sunlight. I then did a test with ordinary Diesel from a gas station and the results I would say, were the same, except it was hard to determine if I got a momentary ignition. The engine was running at 100,000 rpm and throttled down to 45,000 rpm and back up, and then inbetween. It might be that i can squeeze the end of the pipe down a little more and let the smoke run for a few extra seconds, but want to try the system in flight as the airflow might diminish the effect of the smoke. It will be interesting to see how the airflow and tailplane, alters the flow of smoke. I was gutted i couldnt fly due the severe winds we have had in UK, will have to wait another couple of weeks now.
I only have a 7 channel set, so linked the smoke valve to the retract signal, gear up/smoke on. I dont want too much extra weight, so 125ml @ 30 secs will be good for me.
Obviously if i used an electric pump, i then have added weight with the unit and batteries ( or complexity linking into the receiver pack), but most important, i cant switch the system off and fly with the gear up, so an electric pump would run dry and damage would ensue, hence the air tank system which works really well and is light.
The plastic bottle I used was an old Radseal bottle, but if you try this, then do a pressure test of your intended container first with water, not air. This plastic bottle held over 100psi no problem but remember, when the air is introduced, the end of the pipe is open, so pressure will be less than the air pressure in the tank. You could use another metal air tank for fluid containment. I used one NRV from the air tank to the shut off valve and then to the plastic container. I used another NRV from the outlet from the plastic container to the spray bar, so the exhaust gas velocity would not syphon the fluid out, requiring some possitive pressure to overcome the spring pressure in the valve. Pipework will be tidied up later.
Hope that gives some helpful tips on a simple, light, easy to install system that works without requiring any more chanels.
Happy smoking, cheers Tim