Ok, I just installed Tam’s smoke system in my HS and would like to test the nozzle spray pattern. I do not want to use expensive smoke oil for this test and would like to know if it would be good to use regular water in place of the smoke oil. My intention is to draw the water from an external tank (not the smoke tank installed in the airplane) for this test. Would regular water damage the internals of the smoke pump or cause it to rust?

Thanks in advance for your input.

Regards

Ben

Ben,
I don't believe I would run water through my smoke pump. In addition to the rust concern you would not get proper pump lubrication. Even the spray pattern test would not be completely valid due to the different viscosities of water vs smoke oil. I know smoke oil is expensive but use the real thing and get a bucket to catch the spray, then recycle it.

Craig

Ben,
water is quite abrasive in it's untreaed form direct from the tap due to the presence of minerals etc. It will cause premature wear on the shaft seal (lip seal) in the smoke pump. Even if you use deionised water the pump would suffer due to lack of lubrication.

/Johan

Hi Ben,

Just use some turbine fuel mixed with oil,,,,,,,same principle as the fuel pump.......


RB

While we're talking smoke, has anyone ever tried using jet fuel (or kero) as smoke oil? In the ful-scale airshow biz, we sometimes cut the smoke oil with jet fuel to reduce viscosity. Jet fuel and smoke oil are actually pretty similar. It would sure be nice to not have to carry a completely separate system for smoke.

I use smoke oil cut with kero and straight kero in my gassers. I don't see why you couldn't on a turbine. They smoke real well after a flameout. I would still use a separate tank in case you get carried away with the smoke so the smoke will quit before the engine.

Thanks. I use pyro wingtip smoke for most of my airshow routine, but engine smoke would be nice for the last few passes and taxiing by the crowdline. I have a fuel totalizer that reads the total fuel pumped, so smoking the engines into fuel exhaustion won't be a problem. And I carry 11 gallons of fuel Just running out of room for extra stuff.

Ben,

a cheap way of doing your smoke fluid is mixing 30% vegetal oil (same as the one you find in your kitchen to make fries!) to gasoil (diesel) you can also use straight gasoil , works fine too.
In Germany they have that kind of blend directly at the pump, it is called biodiesel, and it smokes a lot.

If you still want to give a try with water , you could use a windsreen washer pump for cars or I believe that they have some waterpumps in the railroad modelling. It is used to make waterfalls or rivers, the pressure might not be enough though...

Florent

What is the ideal spray pattern supposed to look like... I'm experimenting with some nozzle shapes....

Hi Ben,
I been playing with smoke system and is an issue I enjoy to talk and share what I know so far.

There is no need to spend you money on expensive smoke oil when dealing with turbine (which is not the case with gas engines due temperature issue), they will burn whatever you inject in its end, even extra virgin olive oil You can use perfectly gas-oil (diesel) fuel. See the smoke tail on my ex-Viperjet ( ) at full speed on the below picture.

And as per the sprayers.....insert a flat piece of aluminum from a Coke's can at the sprayer tip and using a wise, compress the tip in order to reduce the gauge....do it with the last 1 inch of the tip....then remove the piece of aluminum.
This way you will increase the pressure when pumping, you'll get a more eficiency spraying action and you will reduce the amount of liquid necessary to produce the same smoke tail with more liquid.

Also is important that the flat face of the sprayers tips are oriented facing the turbine rear cone.

I have not try this with electric pumps....just with air....But is the asuming your pump can raise the preasure the ~40 psi as Jetcat's fuel pumps does....then you have a good chance. My suggestion is that the made a test using first a piece os 1/8 inch brass tube...

Best regards,

Miguel


APPARENTLLY THERE IS A PROBLEM IS RCU SYSTEM COS I'M NOT ABLE TO UDLOAD PICTURES AT THIS MOMENT......

.

Miguel, I too am just starting to mess around with the smoke system in my KingCat. I bought a TME pump with variable speed switching (using a rotary knob on my 10X). Testing with water, I am still trying to find the correct 'squeeze' on the 3/16 SS tube, so as to fan and atomize the spray. I'm close, but the next few tests will require HEAT and SMOKE OIL.
You referred to "...that the flat face of the sprayers tips are oriented facing the turbine rear cone..."??? Are you saying, point the tip of the spray into the exhaust nozzle of the JetCat Titan, from 2 or 3 inches behind?
And how does one stop the constant drip or siphoning of the smoke oil when the pump is not on? I mean, mine seems to flow freely (gravity) and will drip the tank empty eventually. Not sure what the fix it there.
LKL

Vacman, a simple shut off valve like a festo or similar will solve the dripping problem. That's what I've seen most guys use.

Vacman,
I suggest you not to use water for testing. The density is diferent from oil....
See the above re-post picture of the sprayer tip.....Install your sprayers so the turbine trust & heat hit the fat face..You want the spraying action to be like bellow picture....specially in a King Cat where you don't have a trust tube.....
Regarding the constant drip or siphoning of the smoke oil....I saw a king Cat with similar problem....Relocate your smoke tank or use a tank with a shape that allow you relocation...like a plastic engine oil bottle....I saw Tom Wood doing this whit one Kit Cat he build for a good friend of mine.
Good Luck,
MS

Miguel,
Thanks for all that. Wow, you've really put a lot of 'flat' into the tube. Works better, huh? Interesting and worth a try. As for 'water testing', to late for me perhaps. I didn't catch the warnings of using water verses kerosene or smoke oil prior to testing. Perhaps running the oil through it now will minimize any further abrasion the water might cause on the pump. As far as the constant siphoning goes, don't know how best to fix that one. Perhaps a loop up higher than the tank/pump, for sure. Using a 'K&S' fuel line pinch will help during transport, etc. Not able to immediately stop the flow once the tank is filled and the pump is made ready for flight appears to be the biggest headache right now. Perhaps the thicker smoke oil combined with the little check valve in place will be enough. Unfortunately, the engine in the KingCat sits lower than the rest of the entire fuselage belly. My perfect fitting tank, BTW, ended up being a plastic liquor flask (20 oz) that fits above the hopper and between the two Kevlar main tanks - right on the CG ($5). It's fairly thick plastic too (a bonus).
You know what might work great is a JetCat type fuel valve, hooked into or mixed with the Fuel Pump command. That's positive shut off!
LKL

The sprayer works great that way, but keep in mind I use air pressure (60psi) instead of a electric pump. Anyway and as I said before in this thread, assuming your pump can build up at least 40psi (??) my guess is it will work.
Anyway, take a piece of 1/8" brass tube and do some testing before making any mods to the SS sprayers you have, and instead of spending money in smoke oil, go with diesel. For the testing you don't need the turbine....When I tested mine, I got an spray action of about 15 feel long and sounded almost like a spray can. I was able to empty a 8.5oz tank in less than a minute at 80 PSI,,,,that's why I reduce the pressure to 60psi.
If you don't get similar results, then play with the sprayer nozzle....you can reduce the length of the flat tip or you can increase the gage.....etc, etc.
Good luck!

You must have the secret injector tube for epic smoke.... They are sold for $25....

Wonderful stuff, thanks for that.
Today, I ground tested the system, titan at engine on 100% and oh my god! At half throttle (half the pulse rate on the radio's rotary) the little TME pump, loaded the entire block (6 or 7 homes) with dense smoke.
I think I got the spray tip atomizing correctly (3/16 SS)! I tested a zillion and two times with a large syringe and water. Reminded me of those college years trying to keep the carpet cleaning equipment's spray nozzles working properly. Guess I did learn something in college after all.
Next test - air time baby, this Sunday.
If this get dialed in, I've got 6 or 7 other jets to consider smoking up. Too much fun!
I get my smoke oil dirt cheap (which is little more than a low viscosity transmission oil with a few secret blends, so I'm told). In fact, ask any oil company distributor if they sale 5 gallon pales of the smoke oil sold to full size competition aerobatic fliers. 5s & 55s generally.
LKL