I've recently taken an interest to ultralight backpacking, and decided to build a small alcohol stove for boiling water and cooking rice/mashed potatoes/whatever at camp.
In addition to some other gear I have to start putting together, this is my build.
It uses the same design as the infamous "penny stove" (although I used a dime), the only difference is I used a "standard" red bull can to make it even smaller.
It's a little finicky to light, but a spray bottle containing the denatured ethanol I use for fuel makes lighting much easier, at the expense of a few extra grams of weight in the fuel container department.
The stowed away assembly.
The top cap/burner base removed.
The cap is placed under the burner to complete assembly.
To light, you simply pour in half of the alcohol you plan to use by removing the dime and pouring in...
...replacing the dime, and pouring some into the concave section of the top of the burner.
After lighting the exposed fuel, it will burn and heat the walls of the burner, eventually creating more vapor pressure in the can. It's at this point that the fuel vapor exits the burner hole "ring" and ignites. The increase in pressure also allows alcohol to leak under the dime and fall into the reservoir.
I use a small steel mug at the moment for boiling, which will be replaced with a $5 aluminum grease pot for a lighter weight in the future.
So far, the only performance specs I have is that it will boil 8 ounces of water in 4 minutes and 55 seconds... not bad!