smoke?

[pulsar110]

this is my first post on this forum, been over at the EDF pages for several years tho. anyway for the last year or so i have been thinking and tinkering with a smoke system for our electric planes. the last week has been very productive and i thought that id share my experience with you guys. as we all know colaborative thoughts are better than one on thier own. the setup in the pic is this:

speed 400 motor/prop to give prop wash.

turbine fuel pump

4 oz smoke oil tank

1.5" alum tube

assorted wires and hoses to wire and plum it all together and yet allow changes.

anyway in most of my prior experiments i was trying to spray the oil onto a hot element. the porblem was getting the right pressure and spray without drowning the element.

a few days ago i had a thought. last spring i did some repair work on a scale titanic that had smoke generators in it. there they had a small coil that was pulled over a wick filled with oil.

so on the inside of my alum tube is a piece of brass tube 3/32" dia that i perforated for 3 inches. the holes are spaced to even out the spread of oil better. it is then wrapped with 2" wide fiberglass heat shielding intended for shielding exhaust headers in a car. out side of that is tightly wound copper wire that i stripped from 12 guage auto wire. the copper is about 30 inches long.

due to the voltage limits of the fuel pump im trying to run it all on 2 cell lipo. the whole thing pulls about 25 amps with this current setup. it creates enough smoke to make a park flyer look pretty awesome.

this is as far as iv gotten so far. there is no burning of the fiberglass but the wire glows red. i drowned it late in the last run today causing a spike in amps. ill dial back the input a bit and try to find the sweet spot.


thought that by sharing this with you guys someone might have a better idea to go with this. im hoping that ill be able to put something like this in my H9 Sundowner F1. That thing is just screaming for smoke as is you guys and your 3D planes.

cheers

[bsipro]

hey Pulsar110
I work in the concert production business and we use all types of smoke / fog
here is a good link that has all the info that you need for your project.http://www.fogfactory.com/index.htm
you will need :
fluid
Tank
pump
heater block
Power (the big issue)
there are some battery powered smoke mechines they high dollar and heavy.
I think you can get a cheap smoke mechine at the mall (Spencers Gifts of a holloween shop) also check out DJ shops.

[pulsar110]

i had considered that as i went to college with a theater major. as you said they tend to be heavy and use alot of power thats why i steered away from them and tried to do something different. right now im at about 3 oz not including the smoke oil. the current smoke oil tank is 4 oz. i know that it will have to be bigger when i get to big planes.

thanks for the input

[kimhey]

This is interesting! Keep us updated on your progress..

[RMS]

pulsar,

Long time ago I started to mess around with the same thing. I was using a brushed speed control to control the heat of the wire and lower the current. I think I tried different pieces of guitar strings, nichrome, etc. I never bought any real smoke fluid............I was using a windshield washer pump driven into a adjustable cleaner bottle tip...like a windex sprayer. Never perfected it or made a good recipe for fluid...never bought any real smoke fluid either. I just wanted to pass on what I tried. It was all of a couple of hours of messing around total.

rms

[pulsar110]

well i couldnt come up with a good go on the electric heat. so while wandering around the local Harbor Freight store lookin at all the cheap stuff i ran across a pen torch powered with butane. "light bulb here" moment. anyway i tried it and wound up with too much heat. DOH! i made 2 coils to test in it. the first one the tubing was too big (5/64") and the heat was lost after about 30 seconds it shot fluid. if i dialed back the amount of fluid it wouldnt create enough smoke really. then i tried 1/16" and burned thru it before i could get the oil rolling. that was the end of the night.

all that said today i got a good look at a slimline muffler with a smoke coil in it. that brought on a whole new idea. will keep yall posted.

[SixDeuces]

This is something I have thought about trying. My idea was a little different, based on a combination of a regular smoke muffler combined with an airbrush.

Basically, a heating tube would be placed on the belly of the plane, close to the prop. Inside, there would be a heating coil very similar to a standard smoke muffler, but sized to be nice and hot on a regular 2S or 3S lipo.

Nothing to earth-shattering there... it's the fluid delivery that's different. Rather than a pump, I'd use a simple brass tube placed inside of the neck of the heating tube, perpendicular to the airflow. The low pressure air passing through the heating tube would draw the fluid out of the brass tube, just like paint in an airbrush (or fuel in a carburetor, for that matter). No need for the weight or complexity of a pump. The size of the brass tube would need to be adjusted until you hit the right amount of fluid delivery. The amount of fluid delivered would vary automatically with airspeed, which takes that out of the equasion.

Besides finding the best fluid delivery ratio, the problem to overcome would be creating a way to turn the fuel and electricity delivery on or off with the radio. I was thinking something akin to the mechanism in a slot car controller. A single servo would be connected to a lever that both operated the fuel valve and made electrical contact for the heating element.

I am sure this would be more difficult to make work than it sounds (isn't it always? :rolleyes: ) but I don't think it would be impossible.

And man, the guys at the field would be SO jealous if you made it small enough for a parkflyer!

[sneasle]

Interesting idea.

Lack of easy smoke in electrics has always been something I've thought about tackling, never had the time or energy to do it.

I will keep an eager eye on this thread.

[pulsar110]

well i need to do a little refinement of my setup now but the slimline muffler and butane torch seems to be a good line to be following. had to ditch the cheap butane torch from HF and go with a better torch that i picked up at lowes. dont really know what the difference is as the flames seem to be the same but i am getting alot more heat out of the torch from lowes. im using my laser temp gun that we heli guys always use to measure the temps of things. the coil was well into the 300 degrees the last test i did.
i wont be able to work on it til after the holidays now as im traveling to visit the family. im thinkin tho that it is a definite possibility now that i seem to be getting somewhere. still looking at some options with the electric heat as well. a guy i fly helis with works with nichrome wire thats covered. talked with him and he is looking to see what he has.
cheers

[sneasle]

No worries, just update us when you can.

I was considering trying ot put together some kind of ignition system for the smoke canisters HL sells for electrics. I haven't actually tried them before, so I can't say if an electrical ignition system would work, but if it did, it woudl give me some nice smoke for a very limited uncontrolled length of time. For smaller craft, this may be ok though.

[3Deranged]

Gave them a try but it wasn't very good smoke trail. Not very long lasting or thick but fun nonetheless. Saw a video on how to make your own smoke bombs and it comes out a lot thicker. Kind of looks like an .049 foamie conversion. :eek: Planning on making a few of my own for some fun. Here's a foamie we tried them out on:
http://www.youtube.com/watch?v=v1QkiEksyCA

[sneasle]

Where did you mount it?

That was kinda pathetic.. I guess those are out as long as I can afford a bit more extra weight from whatever pulsar ends up working out.

[3Deranged]

That was supposed to be purple smoke. Kind of thick when we lit it but as soon as the prop started moving it dissapated quickly. The plastic mount was in the underside of the wing and we taped some tin foil on for good measure. I'll have to experiment around with the smoke formula/casings to get the right amount of smoke. Agreed, kind of pathetic. I think some fireworks type smoke bombs do a little better but the often time have fuses on the side making mounting a little more difficult. The ultimate goal is still cool-a wet type smoke system for electrics! I know it can be done, just going to take some experimentation to get it right. Probably going to need a seperate power system like A123's(fast charge times),pump and of course the smoke oil tank, making it a little weighty for smaller electrics. :( But then again, Jason Noll won an indoor event with a smoke bomb on a foamie! It would be extra cool if the smoke system could be extended to the wingtips. :D

[sneasle]

Well, for what I would like to use it on (P-51's, P-40's, other warbirds and racing style planes) the weight shouldn't be an issue.

On a foamie I can easily see the weight being a problem and the heat as well.

Now, if it can be made small enough that I can install it in one of my 30" wingspan guillows conversions, that would be awesome. But, if it can only be made small enough for .40 sized electrics, that would be fine as well.

[jwilder1]

I have been told that in the past nitro flyers used plumber's smoke bombs. They were used for detecting leaks. I have made my own smoke bombs using potassium nitrate and suger. You need to be careful because even smoke bombs can explosive. I made a fist sized one for our funfly and it popped out of the coffee can I put it in.

[3Deranged]

I would prefer to make the sugar/pot. nitrate kind with orange smoke. Durhams Rock Hard Water Putty is a good way to make a cap/or nozzle. I've used it to make rocket motors before and it takes the heat and bonds well. Casings will have to be experimented on to make the lightest and most durable. Hmmm, got me thinking. They make reloadable/reusable rocket motors now with aluminum casings that would be the perfect smoke cannister. Just need to make a cylinder mold for the smoke propellent to be cast in. Have to look into that. :) I would like to mount 1 on each SFG of my 87" Extra and electrically ignite them in flight with electric matches. And/or 2 more on the landing gear.

[sneasle]

Ya, the only issue I have with those is that they aren't controllable once you light them up. I'd prefer to be able to control my smoke on and off.

[3Deranged]

As I said the holy grail for electrics would be a controllable(wet most likely)smoke system. C'mon people-let's do it!!! Smoke bombs are just for fun. Still would be nice to one up the gas guys and have multiple smoke points on the plane(wingtips, tail, belly :D) Maybe even multiple colors of smoke...

[sneasle]

agreed.

The guy who figures it out will have a nice product on his hands that will probably sell well.

[3Deranged]

Oui', Oui'! I'm 1st in line, called it :D Now do I have any nichrome wire laying around?

[sneasle]

have a look at this:

http://www.rcgroups.com/forums/showpost.php?p=10644544&postcount=299

That the effect your going for?