Thanks for all the help. I've followed most of your advice thus far. got a new book, barrel, and pile of bricks. I've tried two crude test burns in the back yard. Both of which i'd consider promising and a learning experience, but not a success. The biggest issue i'm seeing is that the fire wants to crawl up the wood in the intake and back-smoke.
This is a picture of the most recent burn. There is a brick chimney hidden in the barrel that goes up to about 2" short of the top. After blowing in the inlet I would get what appeared to be a correct rocketing effect, but a few breezes later the smoke would start billowing out the feed tube.
Issues with test setup:
- Not very air tight. Dry stack of bricks
- only 1 segment of exhaust
- wind over intake
Issues that may be in the design:
- The chimney does not have an insulating wide stack (have not come across a good mat)
- Shortness of burn tunnel (i shortened by 1 brick length this go around)
- cross-width size of burn tunnel / chimney
Do you recommend pushing forward and trying to emplace inside of the greenhouse? Hoping the longer tunnel, wind shielding and morter-air tightness will make the burn more effective. Or should I continue to do outdoor burns until I get a shape that works?