Opinion for this rocket mass heater

I want to know your opinion on this RMH model by francis jonckheere / ony one . I want to build a RMH no more than 90 cm and found this model that I really liked. I do not really understand the operation of the two channels. I ask your opinions and recommendations.I`ve attached the plans.
thanks!

awesome, i have always wanted those plans, thanks. the feed chamber is the hole in the middle and the big circle is the bell and the brick channel on the right is the exhaust, the rest of the brick is the mass.

Iutka.

I think, the best way to understand how it's built exactly without doing a mockup. Would be to reproduce those plans with sketchup. Making bricks as "components" duplicating them, and moving them about. I've always loved the look of this thing. Tho, i wouldn't use a J tube anymore. Nor a barrel.

Yes, it's a beautiful design. But is it also a functional design?
All I could ever find about this thing is pictures of the build, a cross-section drawing and even a short YouTube video. But nothing about the thing in operation, pictures nor videos. I highly doubt it was ever succesful.

Well, thinking of it, it might be a bit of a pain to feed. And I wonder if the feed closed on three sides wouldn't act a bit as a chimney. Even more with the hole above. Tho, that implementation might also cut the smokeback puffs.

I`ve ask the owner and here is his answer:
it works very well, but I would change something: as you can see, the barrel is completely hidden in the stove, as opposed to these rocket stoves where part of the barrel is exposed.
The consequence is that my rocket stove has a lot of inertness and thermal mass (stays hot very long after the fire has been extinguished), but there’s not much direct radiant heating. And it would be nice to have a bit more of that.

Iutka, my take on the hiden barrel isue, is to make a masonry bell, with a cast iron cook top capping it, so the exposed surface is a bit bigger than the barrel top. So insteas of the 0.26m² of surface from the barrel top, you could have 0.6, or a bit more depending on the cooktop you find.