Double shoebox rocket cooker with oven & hob

[esbjornaneer]

Here is my suggestion of how to get an oven and hob to work in our cramped kitchen. Improvements/suggestions would be most welcome! Please.

SKP drawing
Orange bricks are full size Spanish heavy firebricks, the yellow are cut in half, and the red are cut in other dimentions.

The SketchUp drawing contains the cutting plan for getting all the pieces for the core out of one 1200x1000x25mm Ceramic/Insulated Fibre Board.
Core is a Peter vd Berg Double Shoebox Rocet. The design of how to feed oven/hob with heat is inspired by Satamax. There is a baffle based on Matt Walkers baffles that directs combusted fumes to oven or hob. And as Peter states that this core can be burned continuously with several loads of wood the oven can first be heated and then baffle turned for cooking on the hob. It may even be possible to heat both oven and hob simultaneously if the right setting on the baffle is found.
The baffle has been left partially open and can be operated with the 'twist'-tool centred on the axle.
The doors have not been drawn, but the frames are based on Matts thread again.
The space under the oven is left for keeping kindling or pots/pans.
Ideally a bell/bench would be connected but there is no space for it in our kitchen.

Questions: Is 40mm thikness of mass in walls, roof and floor of oven sufficient (with 40mm rockwool insulation in floor and 2 walls, burn tunnel behind the other wall and roof, and door in the fourth wall)? Do you think the oven will give better temps and hold heat longer than have been reported in other threads recently?

[josephcrawley]

I may be mistaken but I thought in Peters prototype the expansion chamber roof was the cook top. If so that would allow you to raise the firebox to a more ergonomic height.

I got the file. What would the hob be made off? Would metal hold up in the shoebox? It seems like the designs limitations are the distance to the cooktop and having to either use the top or use the oven.

[Vortex]

I also get "can't find the server at esbjornaneer.com" when trying to view the SKP file.

EDIT: Working OK now.

[esbjornaneer]

Sorry about that I have changed the links to an other host that is normally more stable. I was able to load it just now so hope you all can.

[esbjornaneer]

Joseph, you are absolutely right about Peters build in Allerton Abbey. But they were hoping to use the firebox as the oven. I did that with a previous BBR here at home (my avatar pic) but it was not satisfactory for me. So with the inspiration of the people quoted in the first post I sacrifised the ergonomic firebox for something that will fit our kitchen and that I think will give better heat regulation for the oven. I hope it will.

[josephcrawley]

I spent a lot of time thinking about cookstoves a few years ago when I built a masonry stove of a non rocket design. I more or less copied the traditional sheet metal cookstove I had. This was before the shoebox design so maybe that will make a big change but when using a riser of any kind put to much distance between the heat and the cooktop. So that boiling water took way longer than the traditional stove. I support the burn clean ideas of this forum but if it impairs the function of the stove then what's the point?

[esbjornaneer]

I totally agree with you Joseph about distance from max heat to location of use. In my first BBR I got the oven too far away.

Dec 5, 2017 4:22:36 GMT -8 satamax said:

Well, re looking at this drawing. The simplest solution i see. Keep the original shoebox, as is originally. And move the oven in this pic, to it's side. Bit like the cooktop side channels on the cooking stove earlier in this thread. If the shoebox is made out of insulating firebricks. No heat, or barelly any should be lost.

The above is the nugget I picked up from Satamax. And hence used Ceramic/Insulated Fibre Board for the whole core including the tunnel. So there will be very little heat 'lost' until the gasses have exited the baffle (is the theory). I also sacrificed the glass at the front of the tunnel to keep temps up at maximum. As the gasses need to pass through the tunnel I was concerned about loosing too much heat through the hob if I had put the hob as the roof of the tunnel.