From what i have seen the rocket ovens are the same size. They are usually made out of two 55 gallon metal drums. They probably could be made out of different materials however what they are based on and what is shown here on permies is the 55 gallon metal drums.
Thanks. Yes, I have looked at the Youtube video but have not downloaded the plans yet. I am curious if anyone in thei group has worked in a developing country context where locally available materials are not the same as North America. Appreciate any suggestions!
Steel drums are a pretty universal material. Even if the sizes available locally are different from US standard, the plansshould be scalable by a careful worker.
If steel drums are not obtainable, I have a feeling no other industrialized materials would be either, and local earthen materials might have to be used. This could certainly function, if not quite as efficiently as the "official" version.