I built this Rocket Stove from scrap metal to serve as a daily use wood stove at a training center. I wanted it to be long-lasting, efficient, and work well, and be able to use various fuels including scrounged branches, wood chips, split wood, and eventually pellets [Done - see https://www.youtube.com/watch?v=-OTym69w_j4]. I loosely based it on a model made by Vendel Keresztyen seen at http://youtu.be/k5szviNZZP8. It has a gravity-feed hopper as well as the traditional horizontal feed. The pot can be placed on the insert directly over the fire, or on the grill with the hole cover either in place or removed.
You can see that it burns well and with little or no smoke. I've run it on twigs and branches, wood chips, split wood, and pellets with good results. Since branches are abundant and free at the center it will likely be run mostly on those.
The aluminum ash box holds quite a lot and is easily emptied.
Note: The wood railing next to the smoke stack in the video will be lowered for safety and to give access to the whole surface of the grill top. [Done.]
This has been a lot of work to build but a great project and very satisfying! Looking forward to integrating a Stirling engine into it some day!