Mechanicos had this link upthread. Looks intersting.
“build a small, very hot fire in it, to thoroughly incinerate fuel with minimal exhaust, “
http://www.richsoil.com/rocket-stove-mass-heater.jsp
A rocket stove is going to be tricky to run. I looked into them a couple of years ago. They are similar to masonry stoves with cold exhaust. Basically you don’t lose all your heat through the chimney and have outdoor air leaking into your house. The problem is getting them started with no draft, leaking exhaust, and pushing exhaust backwards down the chimney. That last one is the killer, literally. They are not recommended for people who don’t rigorously maintain the stove and run it properly.