What I am using it for:
I am not concerned about efficiency at all. In fact, quite the opposite - I need this to burn hot and fast so that I can deal with lots of tree branches that need to be disposed of. I live in an area that doesn't allow the burning of green wood due to smoke is illegal and outdoor burning in general is frowned upon by neighbors unless it is an occasional fire pit. I have seen online that the rocket stove burns hot enough that little or no smoke is produced - this makes the rocket design very intriguing for my needs.
So what I want to do is build a decent sized rocket "incinerator" perhaps out of cinder blocks to get rid of my yard waste and make an enjoyable project out of it as well.
I am planning on making a "L" shaped design. I'll call the bottom of the L the "combustion chamber" and the vertical part the "chimney." What I haven't been able to determine from my research is the ratio (in length) of the combustion chamber to the chimney for maximum temperatures / burn performance. I am assuming that a longer combustion chamber would aid in gassification leading to a hotter / cleaner burn. But I haven't seen anything to corroborate this. Some videos of rocket stoves have the wood resting in the combustion chamber but part that is on fire is constantly fed where the combustion chamber and chimney meet. Then other videos like paulwheaton post show a horizontal flame that is in the combustion chamber that snakes into the chimney & a cob oven (combustion chamber) with a chimey which has a flame after-burning out of it.
Is the combustion chamber secondary in importance to a well heated chimney? It is my impression that the hot chimney is more important.
or, for my purposes I am over thinking this? My goal is just a clean burn of lots of organic material.
Also, once everything is heated up will it burn everything including green wood cleanly? 99% of my wood is dry, but there are always a few branches of green wood that have just fallen.
Thanks in advance!