h a l f b a k e r yThe phrase 'crumpled heap' comes to mind.
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//Blow fuel/air mixture into the bottom// |
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I think I see a problem here. The problem involves
words like propagation and explosion. |
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Plastic tube and a hair dryer should allow you to prove you can control the flame. Don't test inside the building. |
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Wet face and hands before ignition so you might keep your eyebrows. Don't wet dryer.
I wonder which plastic tubes support combustion and which simply melt? |
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It's going to become increasingly hazardous just walking down the sidewalk past places of business. |
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"Our accountant informs me that the dramatic increase in customers is offset by our increased insurance premiums." |
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Oh yes. Get those hands really wet before you
handle the hair dryer, [pop]. Have you considered a
career in health and safety? |
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//I think I see a problem here. The problem involves words like propagation and explosion.// |
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Not a problem. Keep the air flow high enough to keep the flame where you want it. |
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If you really want to play it safe just squirt the occasional blast of fuel to make it puff flames like a dragon. |
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And if the worst happens, you could just have the thing held together with breakaway, I don't know, velcro or something. It pops open, you zip it back together and start again. Might even want to end the show with a big bang by stopping the fan. |
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[+] I like the idea of a Wacky Waving Inflatable Arm Flailing Tube Man Flamethrower but, as is, it's a WWIAFTM Bomb. |
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//Keep the airflow high enough// |
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For a slightly less boring surf than Googling for "fuel air deflagration velocity", look in YouTube for "fuel/air bomb". |
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//Plastic tube and a hair dryer// oh, do tell. |
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Long story short, a near-stochiometric mixture of fuel and air will simply blow up right back to where the fuel enters the airstream, pretty well immediately following ignition at any point. |
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If the velocity of the propagation of the explosion is
slower than the velocity of the blower you don't
have a problem. |
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The gang is right about the risks of a stoichiometric air/fuel mix but the risk could be mitigated by delivering the gas to the ends of the cuffs with a flexible fuel line rather than injecting the gas with the air at the bottom of the man. |
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For a look at a roughly similar concept - albeit rigid tubes with no flailing involved - have a look at the Gas Brigade artwork on Melbourne's Southbank. Video link attached. |
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//you don't have a problem// oh well in that case I'll add a buck to 8th's standard offer for "video of me trying this". Remember to get a nice stochiometric air/fuel mixture in your lungs far in advance of the ignition point rather than, say, squirting fuel out between the two upper front teeth where vapourisation/mixture takes place a couple of centimeters away from the face. |
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Though there might be a couple of fringey ways of actually getting it to work the way you envision it: maybe providing a too-rich mixture with a gaseous fuel, like propane, and air. |
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//I think I see a problem here. The problem
involves words like propagation and
explosion.// |
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We think we see an opportunity here. The
opportunity involves words like propagation
and explosion. |
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Stoic fuel-air mixture [+] |
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The fuel air mixture coming out of the crazy guy's
mouth in the video does illustrate the ignition
propagation speed < fuel/air mixture flow velocity
concept. The flames don't reach back to his lips.
The whole thing would have to be fireproof
though. At some point you'd have to turn the air
off and the fire would burn back through the
whole unit that would now be coated with fuel.
So the gas lines direct to the hands might be a
better way to do it. |
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Unless the flames propagating back through the
thing were a neat effect. You could just lean up
the mixture enough to lessen the explosive
impact on the envelope. Then you could have the
whole thing light up, not just the flailing hands.
So you'd shoot a blast of fuel/air mix into the
stream, when it hits the arm hole ignitors you get
the balls of flame that then shoot down through
the thing lighting it up. Make it flexible so it
would puff up and not get ripped to apart by the
explosion. Propane would be the thing to use. |
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Ok, so here's the design: |
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Propane shot into the thing in blasts, not
continuous. |
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Ignitors at the arm holes. |
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Make it flexible enough to expand and vent the
explosion. Venting flaps could also be sewn
throughout. Stiff enough to stay closed when the
air is flowing but would open when the propane
exploded dissipating the explosive force. |
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Make it somewhat translucent so the flames
coming back through the unit would be visible. |
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For that matter, if you're able to explosion-proof
this thing, why bother with the armhole ignitors?
Just shoot a ball of burning propane in at the base
have it fly up through the whole envelope and out
the arm holes. You'd get a Stay Puff Marshmallow man effect. Sell the idea to an antacid maker for a commercial. "Did that bowl of chili make you feel like this?" They might want to re-locate the vent hole to get the idea across better. |
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I don't think you'd have to fireproof it since
the flames wouldn't linger on the material long
enough to set it on fire. You could also atomize
water into the air stream between propane squirts
if necessary. |
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Just make it out of Nomex. As the doc says, if it's properly
vented the material will never get hot enough to incur
damage. |
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