Fire Tornado Rig
Fire. Scourge of Prometheus. Toaster of marshmallows.
It's time to make the elements bow in obeisance to the will of the hacker.
This rig is all about static airflow. It's a giant box, open on both ends, with strategically placed air intakes on each face of the box.
A contained flame source, in this instance, jellied alcohol, is placed in the center. As the heat rises, air is drawn in through the slits in each face of the box, and each inflow region is deflected by the path of the next face, causing the incoming air to rotate.
As this rotation is drawn into the flame, the speed of the rotation increases due to conservation of angular momentum, and a vortex forms in the center.
This rig needed some tweaking, to ensure that the area of the updraft was narrowed down, to prevent air from flowing down from the top of the box, and breaking up the vortex.
After version 1 was successfully tested, we at UAS decided to go big, or go home. We discussed several models for new rigs, some of which are still options, but the simplest method involved a rotating screen around a flame.
You can attempt to rotate a flimsy screen at high speed, or build an entire rig that rotates, based on a "lazy susan." When you're intentionally playing with fire, it helps not to burn yourself.
Remember: If you build a man a fire, he will be warm for a night. If you set a man on fire, he will be warm for the rest of his life.
We built a not-so-level, and not-so-square 2x4 frame for the lazy susan. (UAS needs a framing square and straight-edge BADLY!) But, it's a prototype....
On top of that, we mounted the circular wooden turntable, and a piece of drywall to limit combustion to the areas that we wanted. Then affixed a cheap pie plate to the top to hold the fuel source.
Our first screen roll was a thin gauge aluminum window screen, flimsy, and just tacked into place. When it lost its shape, and encountered the vortex, the screen started to melt. Also, the flinging around of the turntable by hand was less than optimal.
Necessity is the mother of invention. Pyromania is the bastard red-headed stepchild who melts your toys.
First order of business was to re-engineer the screen, with a roll of chicken wire as the solid core of the cage, far sturdier, followed with a outer layer of the aluminum window screen, carefully and meticulously sewn together with wire.
Next was a far more energetic fuel source - its effectiveness is up for debate.
Finally, the turntable was motorized. C-P will add the details of the motor rig here:
Parts and pricing: Lasko 20" 3-Speed Box Fan: Item #: 95021 | Model #:3733 Price: $14.99 Quantity:12 Subtotal:$179.88
CARLON 4-Gang Plastic Old Work Electrical Box Item #: 130186 | Model #:B468R Price: $6.10 Quantity: 1
6-Outlet Surge Protector 312 Joules with a Bonus 6-Outlet Power Strip Item #: 130745 | Model #:PBCB0004L Price: $10.97 Quantity: 2 Subtotal: $21.94
Utilitech 6' 3-Outlet 16/2 Extension Cord Item #: 70291 | Model #:10018 Price:$1.67 Quantity:8 Subtotal: $13.36
Lutron 5 Amp White/Ivory Fully Variable Ceiling Fan Control Item #: 155194 | Model #:FS-5FH-DK Price: $9.48 Quantity:4 Subtotal: $37.92
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Estimated Total $274.76