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"cannon ball" of smoke - shooting out toward audience

Discussion in 'Special Effects' started by danl, Dec 11, 2006.

  1. danl

    danl Member

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    i saw a show YEARS ago in which a cannon was fired and a ball of smoke (a literal BALL of smoke) shot out into the audience...

    has anyone seen or made this effect??? can it be purchased??? made???

    any help would be awesome!!!

    thanks!!!
     
  2. silvrwolf

    silvrwolf Member

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    I would suppose this setup your talking about would be somekind of gas held in a holding tank at a high pressure. To get the sudden gas out a quick release valve is used. I have seen this used in the theater, but recently I saw the same idea used on "mythbusters" that show on discovery channel. THey used a real similar setup to make a frozen chicken blow through a planes window. Its very big but it would probally fit your needs. I believe the name of the device is a chicken gun.
     
  3. SHARYNF

    SHARYNF Well-Known Member

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    This is really a variant on the old blowing smoke rings trick back in the days when people smoked a lot

    If you get the smoke into a chamber, and then use are to push it out, you can have a ball of smoke sent out over the audience

    Basically you need a source of the smoke, and source of some compressed air

    It is possible to do it with a pvc tube say looking like a canon, you would feed the smoke in first, with the front of the barrel closed to hold the smoke, then switch to compressed air, and open up the front of the barrel and you will have the smoke projected out over the audience.

    You can do it with a co2 fire extinguisher since it creates a cold smoke that tends not to rise, and then a can of compressed air to propel it If you wanted to get more mechanical, you could have a plunger type device in the pvc tube behind where you put the smoke in, you then fill the forward chamber, and at the same time as you unblock the front exit you ram the plunger forward could be rubber or bungie controlled ,

    Basically the smoke will tend to hang together especially if it is cold. and since it is very light but denser than the surrounding air, you can puff it out.

    There used to be a large bill board in NYC that was an add for camel cigaretts, then had a person smoking and the system kept blowing smoke rings

    Sharyn



    Sharyn
     
    Last edited: Dec 14, 2006
  4. CHScrew

    CHScrew Active Member

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    Have you ever seen one of those "AirZooka's"? They have them in toy stores. Here is a link. If you filled the bucket part of it with smoke it might work.
     
  5. SHARYNF

    SHARYNF Well-Known Member

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    Might work, uses some of the same principles
    Sharyn
     
  6. Van

    Van CBMod CB Mods Premium Member

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    Occupation:
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    I think the Airzooka is a closer match to what you'll want for this SPFX. What you need is sort of a HVLP system < High Volume Low Pressure > your'e going to need to expirement with diameter and length of tube. the effect you are looking for is very similar to "tuning" a pipe organ. You have to establish the proper volume of air to acheive the proper "wave-length" or it'll be just like blowing a bunch of smoke through a straw, it'll just come out the other end in a big long stream. I would think the math would something along the line of needing to move the volume of air of a given section of the pipe.
    Let's say you use a six inch pipe. let's say you're going to "fill" approximately 6 inches of pipe with "smoke" you need to do the math. < I suck at remembering things like this > So compute the volume of smoke your introducing to the pipe, Your'e going to want to move that same amount of air out of the pipe in a single "pulse" This is where the AirZooka might come in handy as a study guide. I believe you could stretch a rubber membrane of some kind across the end of the pipe, or perhaps use a piston of some sort, to pulse the air through the pipe. Like I said earlier the key is not moving a huge volume of air through the pipe all at once it's all about controlling a single pulse of air through the pipe at a given velocity. **** ! now you've intrigued me ! I may just have to go waste some time in the shop expirementing !!! I don't have time for this !


    Ok I'm back, just walked away for ten minutes, I'm not sure if what I described will provide you with a "ball" of smoke as much as it will provide a "smoke ring" I recently saw a gun at a local theatre supply store that blows smoke rings if you could find one at a Spencers Gifts or some place like that it might provide another research tool, to at least provide proportions and you can scale up from there. Good luck Let me know what you come up with and if I can drag myself away from doing working drawings long enough I'll try and play with it here in the shop.
     
  7. saxman0317

    saxman0317 Active Member

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    I would try makin some sort of a diaphram type deal, kinda like a bellows, but more whoopie cushionish. Have 3 ways for air to get in out of it. One will go to your smoe source with a check valve only letting the smoke into yor device. One will be a release valve that you can open manually if too much smoke gets in, or open it to let the bellows have someplace other than the smole just blown on stage to draw air from after the emptying. And the last one will be your "nozzle" end itself. This is the priniciple that disney used in the Pirates of the Carribian ride and ive used for a few effects including a smoke stack that was supposed to "comically puff out little balls of smoke in order to render a more comical and less serious roll as to the purposes of the factory therefore connected"
     
  8. SocksOnly

    SocksOnly Member

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    If anyone makes a "smoke cannon," it'd rock my socks if you'd post a pic. Maybe I'll (try to) make one, if I get bored over the holidays...
     
  9. danl

    danl Member

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    okay, i actually went out to look for the gun at spencers (if only to study it) and ended up finding the airzooka!!! i played with it for a long time, and eventually attached it (sort of) to the back end of a 4' PVP pipe of nearly the same diameter... a little bit of duct tape and i had a mildly good seal...

    for the smoke, we first tried a smoke machine, but it was too powerful with poor control... (the smoke blew out of the "front door" that we put on the pipe before i had a chance to open it...) then it was on to the pea-souper... much better smoke control inside the pipe... let it fill up pretty good, had a friend open the "front door" while we pulled back on the airzooka on the opposite end... i was really anticipating something quite special... hrmph...

    got a <i>sort of</i> smoke ring, but a pretty sloppy one... it just looked like a wimpy poof...

    sigh... still looking for more ideas!!!
     
  10. SHARYNF

    SHARYNF Well-Known Member

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    I think that temperature might be an issue, I'd try CO2, have never done exactly what you are trying to do, but possible either having the smoke be colder or warmer might help.

    Sealing off the front so that you get a compressed bit of smoke might also be a factor

    Sharyn
     
  11. danl

    danl Member

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    not sure about the CO2... i wouldn't even know where to begin on that one... i wish i could remember the theater that i saw this in... it was great!!!
     
  12. SHARYNF

    SHARYNF Well-Known Member

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    co2 would be from a fire extinguisher for example
    Sharyn
     
  13. silvrwolf

    silvrwolf Member

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    If you are near Springfield Illinois, there is a new museum based on President Lincolns life that has a theater with a totally automated show which has probably 13 full scale cannons which appear from hidden panels that drop down on the wall and fire rings of smoke. To add to the affect, the theater seating is equipped with one buttkicker motion device per every two seats. Its an awesome place to visit if you into advanced lighting and automation. They also use a variety of high tech 3D projects (not the ones where you have to wear glasses to see it).
     
  14. SHARYNF

    SHARYNF Well-Known Member

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    The rings of smoke seem easier to do, like someone blowing rings of smoke, getting a round ball seems to be more difficult
    Sharyn
     
  15. soundop

    soundop Active Member

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    the show is all holographic, so that effect would cost alot of cash, but it is a pretty good show
     

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