A B C s of smoke systems
 

My son flies a Sig 4* 60 that I built for him. It runs a Magnum .91 four stroke and an airtronics 4 channel radio. He flies it, I am the chief mechanic.

He is dead set on getting a smoke system. We have been in the hobby for three years and are pretty handy with the planes but we know nothing about smoke systems. Surprisingly, although our club is quite active, nobody there uses a smoke system. I think I've seen one in three years.

Sooooo, what's the scoop on smoke systems?? Can you guys give some recommendations, pitfalls, etc?? I already assume he will need a six channel radio rather than the four channel he is using. What else??

Thanks,

JPF

A B C s of smoke systems
 

The biggest wall you are going to hit is room in the plane and weight. That size of plane will be tough to get the system in. You need a tank a pump and a battery all mounted around the C.G. All this stuff together will be about a pound. Smoke systems are cool but try an experiment for me. Put a pound of lead on the CG inside your plane and fly it. The 4 Star can handle the weight but I bet it flyes like a turd with that extra pound. You guys should wait until you have a bigger plane. If you want to have fun with this one try putting 20' of streamer on the tail and maybe each wingtip. It's not smoke but it looks cool.later daveo

A B C s of smoke systems
 

I'm not actually sorry to hear that it may not be practical to smoke on our Four Star.

I guess my son can start thinking about a bigger airplane!!

Thanks for the info.

JPF

A B C s of smoke systems
 

Well. You can get a smoke system in the 4*60, you just won't have a very large smoke fluid tank/ (you can trade a smaller fuel tank for more smoke fluid)

The smoke pump itself would mount below the engine. The second battery to drive the pump (never power it from the RX battery... you can accidentally drain the RX battery too easilly) is placed to readjust the CG compensating for the pump.

A 4 oz smoke fluid supply is about 90 sec of smoke for a .91 4-stroke. (just enough to know you've really been laying a smoke trail and impress the others at the field)

The hard part is making sure you get the smoke fluid injection point at the low pressure area of the muffler... If the injection point is in the main expansion area, you won't be able to inject fluid above 1/2 throttle without presurizing the smoke tank. (not a good idea...)

The TME smoke system is really good. [img]i/expressions/face-icon-small-wink.gif[/img] They've got a nearly complete (no battery or tank) system for appx $90. There's plenty of info on setup in the instructions. The pump is controlled by a circuit board which plugs into ne of the radio channels. This board has an isolation circuit to power the pump from a second battery. I use a 5 cell pack to power my pump. (supplying a O.S. .91 FS.. close to your Magnum in how it would need to be set up)

A B C s of smoke systems
 

I fly a Joss stick, which is maybe a little more weight worthy when it comes to adding a smoke system. I have a Harris smoke pump, which plugs into the receiver. (I use the gear channel). I run a 1200 NmH battery, and no the pump uses minimal voltage for the time you use it flying. (Unless the pump were to stay stuck in the on position. The fuselage was just large enough that I could add a 6 oz. tank, (run about 5 oz. of smoke fluid). I used a TME clamp, (tower hobbies web site has TME products so you can familiarize yourself with them). A friend of mine from Minneapolis flies a giant 540 Edge, that uses about 32 oz. of smoke fluid in a flight, but it is awesome. I flew my plane at our fun fly, and he wanted to know how much smoke fluid I had in it, because it just keeps on smoking. I said, 5 oz., and he couldn't believe it. I also have a pitts smoke muffler on it. The key is probably in the TME smoke clamp which allows you to precisely squeeze off the smoke tube, to get just the right amount of fluid going through, that your engine and muffler can adequately burn for the temperature you are running. Mine doesn't smoke like the gas engines, but it does a nice job. The fuselage had room, but barely, for the pump and extra smoke tank, but I got it in there, on the CG. Do some research and look for a plane, that flies well for your son's capabilities, and one that has a large enough fuselage, and it takes some work to add the extra hoses, etc., but it definitely adds to the effect. Also, for smoke systems, you have to use tubing such as Tygon or polypropelene, as smoke fluid will eat up the regular silicone tubing. Any other questions, just e-mail me.
Brian, Minnesota

A B C s of smoke systems
 

I forgot to mention that I run the smoke system using an OS .91 four stroke. How does that Magnum run?

A B C s of smoke systems
 

We are really pleased with the Magnum .91 four stroke. We have had two Magnum .61 two strokes and have occasionally had deadsticks for no apparent reason, but this .91 fs seems to be much more reliable and it really pulls the four star.

A lot of the guys at our club don't like the Magnums but some of them are sort of equipment snobs.

I am assembling a 60 size ugly stick for me and my other son to fly. I have a magnum 61 2s for it, but I may spring for another .91 fs. The fuselage is cavernous compared to the four star, maybe I'll consider a smoke system for that plane.

Where do you fly in Minnesota? I used to live there.

JPF