Ernie has been talking about rocket stoves lately. This is the one I've designed and have been using for 7 years.
Designed in blender
Made from 1/4" steel. Weighs about 500 lbs.
Lined with firebrick and a custom heat riser so fire never touches the steel. Have had to replace bricks & risers over the years, but zero damage to the steel.
I've been able to heat my ~1500sq.ft home on about 2.5 cords of wood per year/season. I haven't used a traditional wood stove for comparison, but would guess the rocket stove uses 1/2 the wood of a traditional stove.
I also reduced my propane cost by ~70%
Here are the build plans I gave to the fabricator.
Got a lot of ideas from this guy (Youtube). He has a lot of videos building and upgrading his stove.
What would I change?
The tolerances were a little too small for the bricks. So when replacing the bricks, I have to trim them to fit.
I didn't add a secondary air intake to deliver clean, preheated air to the base of the heat riser. This is supposed to increase performance/efficiency.