Cooking on the top of a batch box rocket mass heater

[natdak]

I have been thinking of a design for my rocket mass heater, inspired by this thread: donkey32.proboards.com/thread/1568/batch-cooker
To cook ontop of a batch box heater seems to be a very good solution if one wants to have a cooking surface as a primary function as well as the heating of a rocket mass heater.
The stove I will build will be a 220cm² CSA system. I have a cast iron plate measuring 50cm x 35cm. It has 2 cooking plates, one smaller, one bigger with removable rings to put pans on so that the pan can be in direct contact with the flame. I would like to call upon the expertise of peterberg matthewwalker satamax and any others with experience with this. Is it acceptable to have removable rings and a pan in direct contact which will inevitably leak small amounts of air from around the rims into the system from the top of the batch box? And are the dimensions of the plate compatable with the recommended dimensions of the batch box? I understand that the barrel will cover a part of the batch box and I imagine that if the cast iron plate is located right up to the door of the batch box it might not receive so much flame and heat.

[satamax]

Firebox and heat riser usually are at less than atmospheric presure, so they're sucking air, not leaking vases.

[natdak]

Okay good. will it affect the performance? It would make air flow harder to control, perhaps it is negligable or can be controlled at the air intakes? How is your heater doing? Is the cooking top practictal and functioning well? Perhaps I wouldn't need the pans being directly exposed to the flame and one piece of cast iron would suffice? I'm also curious as to whether you can fit 2 decent sized pans on there? Same for matthew walkers batch burner? For me it is a requirement that it can fit 2 to make to practical as a primary cooking source.

[satamax]

I have a piece of cast iron. It is often too hot to Cook directly on. Si frying pans etc, are required. I love it for stews in the depth of winter.

[satamax]

[natdak]

You mentioned in your thread that it took over 40 minutes to get water boiling. How did you manage to fix that issue? From what I understand about the nature of the burn in a batch box heater is that one burns a large quantity of wood in one go and is repeated several times in one day. Is the length of time that it burns for and stays at a cookable temperature practical enough to cook meals? What if one would load a smaller quantity of wood in? Would performance suffer?

[satamax]

Natdak, the thing to remember, if you Cook on the top plate. Is not to Cook before well past the middle of first burn. Second burn is better. It's demential when the water sizzles on it. When it does, it's fantastic to Cook meat.