Tornado Cat

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WanderingStovie
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Tornado Cat

Postby WanderingStovie » Mon Jan 12, 2015 9:47 pm

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Here is my Tornado Cat alcohol burner. I started with Jim Wood's Simmer Cat, added an inner wall with pressurized jets angled inward to produce a tornado-like flame (used by JSB, KMKMR22, LittleBitWorks, Tetkoba, and others), and lined the walls with capillary hoops. I do not add grooves or creases to the capillary hoops (or virtual wicks, as Don Hitchcock would call them). There is no need for a strip skirt, due to the shape and size of the cans used. I form the capillary hoops from strips of aluminum. I join the ends without fasteners, since eyelets or staples would interfere with assembly.

I use the pull tab to remove the top of a 3 ounce aluminum can of cat food or potted meat. I roll the inner lip downward, flush with the inside of the can, using the side of my center punch. I remove the bottom 4 mm, leaving 33 mm. I leave the cut edge rough to allow fuel to flow freely to the capillary hoops. I used a compass, pen, ruler, and circle cutter to make a 63 mm disc with 9 evenly spaced lines extending from the center to the edge. I use the disc to place 9 evenly spaced marks around the top edge of the can, as seen in picture 2. I press the center punch into each mark at the line where the inside diameter decreases. I use a #70 drill bit and a rotary tool to drill 0.71 mm holes into the indentations, through two layers of aluminum. I angle the drill bit as seen in picture 3.

I cut two 25 mm wide strips of aluminum from the side of an aluminum beverage container. I use a 23 fluid ounce Arizona tea can, but a 12 fluid ounce soda can would also provide suitable (and thinner) material. I wrap the first strip tightly around the cat food can and mark the overlap. I add 1 mm to the circumference and join the ends by cutting tabs along both edges of the overlap, and bending the tabs outward (away from the cat food can). See pictures 4 and 5.

I remove the top of a steel 4.25 ounce Underwood deviled ham can with a "safety" side cutting can opener. I wrap the second 25 mm wide strip tightly around the inside of the steel can and mark the overlap. I subtract 1 mm from the circumference and join the ends with tabs cut along both edges of the overlap, bending the tabs inward (away from the steel can). See pictures 6 and 7.

I place the top 33 mm of the cat food can upside down on the table, slip both capillary hoops over the cat food can, and press the steel can down around them. I flip the steel can right side up, and push the cat food can into the steel can until it rests on the bottom. See pictures 8, 9, and 10. I punch 27 evenly spaced 3/16" diameter holes in a row centered 5/16" down from the edge of the steel can, as seen in picture 11.

For more pictures, please see http://www.appalachiantrailcafe.net/gallery/index.php/Album/33-Tornado-Cat-alcohol-burner/

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WanderingStovie
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Re: Tornado Cat

Postby WanderingStovie » Mon Jan 12, 2015 9:54 pm

The Tornado Cat alcohol burner described above is my second attempt at making this type of burner. The first version used the entire height of the cat food can, with a large hole cut in the bottom and four slots filed around the bottom corner. There were only 9 air holes 3/16" in diameter. The capillary hoops were different.

The first version took 40 seconds to bloom. The current version bloomed in 12 seconds. Ah, progress ...

If the wind dies down, I will try using it as a Simmer Cat, with the pot balanced on the rim of the burner. The previous version did not stay lit. The new version has 3 times as many 3/16" diameter holes, with the equivalent area of 15 holes 1/4" in diameter, as found on Jim Wood's Simmer Cat.

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zelph
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Re: Tornado Cat

Postby zelph » Tue Jan 13, 2015 12:30 am

We want to see some flames coming out those jets!!! :D we need photos :mrgreen:
"Nothing Ventured Nothing Gained" stove store = http://www.woodgaz-stove.com/

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WanderingStovie
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Re: Tornado Cat

Postby WanderingStovie » Wed Jan 14, 2015 12:11 am



I made a short video of lighting my Tornado Cat, using it with my tripod stand, and using it like a simmer cat. I have some work to do if I want to use it like a Simmer Cat, as seen in the second half of the video.

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zelph
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Re: Tornado Cat

Postby zelph » Wed Jan 14, 2015 12:44 am

This video starts with the lighting of my Tornado Cat alcohol burner. After about 12 seconds, it blooms and the jets converge to form a tornado-like flame. I demonstrate placing a pot with 2 cups of water over the burner on my tripod stand. I remove the stand and set the pot directly on the burner.


What we're seeing is air on the outside of the stove trying very hard to get inside the burner due to up-drafting of air. Negative pressure on the inside of the burner causes air to enter the holes and ignite with the vapor inside the burner.

Has anyone ever seen that happen with a Super Cat stove ? I have not.

How is your stove going to operate when it's completed? With an external stand or like a Super Cat?
"Nothing Ventured Nothing Gained" stove store = http://www.woodgaz-stove.com/

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WanderingStovie
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Re: Tornado Cat

Postby WanderingStovie » Wed Jan 14, 2015 1:08 am

The Super Cat has two rows of holes, so it is much easier for oxygen to get in, but when it is hot enough, flames come out both rows. The Simmer Cat has one row of holes. I suspect the holes on my stove are too close to the top edge, and there is not enough thermal feedback, and the fuel vaporizes too slowly.

My goal is to boil water in a hurry with a pot stand, and simmer without.

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zelph
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Re: Tornado Cat

Postby zelph » Wed Jan 14, 2015 11:51 am

Jim Wood's Super Cat will boil 2 cups in 4 minutes if I remember the results when I test his design. The thing I didn't like about the design was the stove would stick to the bottom of my pot due to alcohol collecting on the bottom of the pot and causing a "seal" around the top lip of the stove. Once my water came to a boil it was a natural thing to lift the pot up and the stove was still lit and sticking to the bottom of my pot. Once the pot was tilted a little the stove would fall off and burning alcohol was spilled. That was a little scary. Further experiments showed I had to wait till the stove went out before lifting the pot.

The Super Cat was my inspiration to design stoves with integrated pot supports.
"Nothing Ventured Nothing Gained" stove store = http://www.woodgaz-stove.com/

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WanderingStovie
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Re: Tornado Cat

Postby WanderingStovie » Wed Jan 14, 2015 4:23 pm

So what keeps your stoves with the inner cylindrical pot support from doing the same thing?

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zelph
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Re: Tornado Cat

Postby zelph » Wed Jan 14, 2015 8:25 pm

WanderingStovie wrote:So what keeps your stoves with the inner cylindrical pot support from doing the same thing?


I only have one stove that fuel is poured into the center and forms a puddle and that is the Fancee Feest. The "V" notches at the top of the pot support prevent the stove from sticking to the pot.
"Nothing Ventured Nothing Gained" stove store = http://www.woodgaz-stove.com/

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WanderingStovie
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Re: Tornado Cat

Postby WanderingStovie » Wed Jan 14, 2015 11:50 pm

I watched you pour fuel into the center of the GoTo and light it. When you took the pot off, fuel was burning on the bottom of the pot. I am guessing you probably notch the top of the pot support for the GoTo as well. Sorry if I am being a pain.

And condensed fuel is not the only liquid that can form a vacuum seal between the stove and the pot. Early in the burn, water vapor condenses on the pot, at least for stoves I have built.


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