I have read through How to Build A Rocket Mass Heater.
In it, if I didn't misunderstand it, it recommends a 6-8 inch diameter J Style firebox. It also mentions that the heat riser should be about 3x or more of the length of the fuel feed, and about 2x the length of the burn tunnel. So a 16 inch fuel feed would have a 48 inch heat riser.
My question is, are these proportions/sizes/dimensions good to se the the J style firebox itself as a cookstove? If I place some sort of grate/pot stand on top of my 48 inch riser and then place a frying pan on top of it, will the heat coming out of it be enough to fry with? Will actual fire be shooting up out of the riser (just like those metal rocket stoves I see on youtube, whose dimensions I cannot ascertain) or will it just be exhaust?
I haven't had time to prototype yet since I am looking for affordable places to get firebricks.
Thank you very much for anyone who can share their experience.