Dick Boyt has built a stove out of ten cans of various sizes. The drawing below shows how it fits together and operates.
The following diagram is a sectional view of one side, of the bottom portion, of a similar stove. One difference is where the air supply enters the outside can. The drawing was meant to depict the true size of the stove. I have inserted the "9 inches" measurement on the side, as a reference. It printed out full size for me.
To use this stove, you fill the combustion chamber with dry twigs and light it by dropping some burning paper down the chimney on top of the twigs. The wood will pyrolyse from the top down and then the char portion will burn from the bottom up. The graph below show the point at which it becomes a charcoal fire as labeled "flame out".
Below are a couple of detail drawings to assist the builder.
Notes with the photos:
The stove is siting on a concrete block. The pot is sitting on a flint striker just to creat an exhaust space between the pot and chimney. There are better solutions to that problem.
This shows a partial breakdown of the stove. On the left is the tiny multilayered cylinder which is packed with twiggs