Ruben Masson

Yep, nice!
Saw your topic and videos about the 4 inch vortex rocket. Cool man!
Kind off doubting to change mine into a vortex or DSR...

I don't seem to find any drawings (sketchup) from the vortex types. All files on donkey proboards i found aren't reachable anymore, and it seems like quite a tricky built..

Thanks for the reply!
Well... Clearly the stove uses 'rocket science'.. the secondary burn of the gases here just happens under the cooktop itself.
Without any insulation at the moment, when it's all insulated I think it'll get a lot more efficient.
And that's what I'm wondering about, how to get to insulating this one properly, so it gets 'max efficiency'

Yeah, a long chimney will improve pulling for sure.. right now, I just have this, but when i make the final design in the kitchen i'll put a long chimney through the roof.

I know about fixed/tested rocket designs and have made a BBR before. Doesn't mean you're not allowed to experiment with what you have, right?

You mentioned well tested J tube cookstoves. Haven't found clear topics or models on this though... That don't focus on heating the house as well.
Have you got any good recommendations or links?
Thanks 👍

Hi guys!
I'm in the process to design and make a rocket cookstove to put in our natural outside kitcken we are building here.
Next to a rocket oven (about which I have another topic going on 'search for rocket oven designs'), I want to build a normal cooktop as well, and with rocket science integrated, I hope it will be quicker and more efficient then these old style wooden cookstoves.

The aim for the kitchen is that it will be the center point in the community. Used by people living here and by visitors who stay on our small natural camping.

As I'm planning two wood fired 'installations', I hope to catch the leftover heat from the chimneys with a thermosyphon system. Heating up water through copper pipes around the chimneys, that feed a boiler hanging under the roof of the kitchen. Ideally this water could be used for dishes and in some outside showers, still to make . Any tips or advice for systems like this? Ofcourse pressure valves

I've been researching a bit on different models and types of rocket stoves to cook on. Although most I found had also the purpose to heat or at least add to hiuse heating. The one i'm building will be in a half open outside kitchen, so I hope to focus the heat as much as possible on the cooking surface.
I stumbled on some videos from a guy who made a very small, efficient rocket cookstove, that looks very promising. It's basically an L tube flipped down, or J tube with flat riser. The top of the 'riser' is actually the cooking surface, so where the heat gets hottest it gives the heat off to the cooking surface.
These are the videos i'm talking about. Very interesting bunch of videos actually. https://youtu.be/VFAwl6aJNH4
So, with this design, I went on to experiment. I had an old wooden stovetop still laying around and imagined that would be a good size for the cookstove I want to make in this kitchen. Clearly a lot bigger then the one in the video, but I can also get quite a bit bigger in general with the system.
I got some firebricks and went on to make a quick experimental set up. First time i just put one layer of the bricks (7cm) and a bit of clay to close the gaps with the stovetop. Made a little firebox and added a diy chimney.
With this version, I couldn't get the flame and gases through the system.
Too small get it pulling good.
Next day I remade it 2 bricks high, so 14cm and a bigger firebox. This went a lot better already, once the chimney started pulling it went really good and got to +-300°c on the first place to cook. Then I modified some parts, added a ramp to push the heat up and added my secondary air channel from my BBR inside in there. Then it went really well. I got to +- 330°c on the first pit and 250°c on the second.
The downfalls still present are the time to heat it up, and a little struggle to get the pull going in the beginning. Ofcourse this experiment is without any insulation. The final design I'd like to insulate very well to it focused all its heat to the cooktop and heats up quicker, also a real, long chimney (that's insulated?) Will be better for a good draft I guess?

Do you guys have any suggestions on how to improve this design? How to focus most efficiently the heat to the cooktop? How to insulate it properly and what materials to use for it?
Many thanks for your suggestions!!

I'm adding some pictures with description to this so you'll know what i'm talking about more

Grtss an excited rocket experimenteer

Hmm, yeah
Some kind off diffuser would be beneficial for sure..
I don't have a clue though what that diffuser could be made off..
My riser is entering the oven space completely at the back so actually it only has to push the heat forward and sideways..
I wonder if it's really necessary to have this as it will complicate the design quite a lot, I think.
Might not be too big of a problem if this hotter spot is completely at the back..
Do you see a sort off easy way to integrate a diffuser?
And how much space would this area unde the floor need? I have 7cm high fire bricks atm.. it might be a bit small, i think.. can get 11cm ones as well, or immediately 2 small ones on top of eachother..
Many possibilities..

Hi Glenn!

Thanks for your contribution to this topic man! This is exactly the type of 'experience' i'm looking for!
That's very valuable information! Amazing project and amazing lessons for the next builders! Thanks a lot!
So, if i understand correctly, in your design the floor is too thick to heaten up good to let's say pizza temperatures (250-300°c) ? And you suggest that having a single layer of fire bricks as the floor (where the hot gases touch the bottom of the fire bricks directly) would solve this problem?
That's amazing! That's exactly how I imagined to do it. In fact, i bought already fireproof tiles for it. They 20*20*3cm. Now i'm wondering, is that too thin? Maybe it'll get too hot? Other option would be firebricks 4cm thick. But they are quite a bit smaller so will make it harder to make a nice floor..
Any thoughts?

How about your chimney? Are you loosing a lot of heat through it as it is quite high in the 'bell'?
I'm considering using a bypass system, where the top one(that you can close) is at normal height to get the chimney pulling quickly, and the bottom one, under the floor/at the level of the floor.
Any thoughts?
Thanks man!

Any thoughts?

Hi guys!
I've been too ambitious with timing and let go of the progress of the kitchen for a while as there were many other projects going on here.
After reflecting on the plans and getting all excited about rocket stoves again (as i'm using my batchrocket everyday now in winter) i want to get started with the oven to hopefully have a good functioning pizza/cob rocket oven during the coming warmer seasons.
Since i did some more research, I realised that that is the challenge with rocket cob ovens, having the base/ground of the oven warm enough to cook pizza's. And makes a lot of sense as heat rises and with fire underneath there's no fire laying on top of the floor like with usual cob ovens.
So I've been researching and found some interesting ideas/designs. My plan right now is to build a well insulated 150mm batchbox underneath and have the warm gases pass under the floor of the oven before
Entering the dome/bell. A bit like this design I stumbled upon.
https://lhalfo011.wixsite.com/rocket-vs-oven/my-design
My question here is how and out of what material to make this floor where the heat passes under. It has to be able to resist the chock temperatures from the rocket stove and hopefully store a good amount of heat for some time without became way too hot too quickly. I want to use as much local and local sourcable materials as possible so I was researching in casting something. Someone has advice on what to use to cast this floor so it will fit these requirements? Clay/cob would be easiest but will crack won't it? (I have it in the soil) My other idea is to use firebricks. But for that i'll have to create something where the firebricks are laying on and seal them with the fireproof mortar. Any suggestions on what to do?
For the chimney i'm not so sure yet either. Don't plan to make a double door like on the plan I linked. I'd like to go for most efficient use of the heat of course so having the chimney quite low in the oven or even having it in the area underneath the floor is my idea so far (although with this idea i wonder if the chimney would just pull the heat gases from the riser immediately before them entering the dome, that wouldn't be ideal ) any thoughts on that?  

I'm also wondering if adding a copper coil thermosyphon (around the riser or around the chimney or both) takes a lot of the efficiency of the oven part away. If not, I'll add something like this also so we'll have warm water for the dishes after.
Any thought/ideas or suggestions for this project?


Next to this oven i'd like to make a rocket cookstove as well. Will do some experimenting with j tube and an old cast iron cooktop soon.

Will add some pics of a quick sketch on my plan so far and the kitchen so far.

Enthousiastic rocket smile
Ruben

Thanks Thomas for your inspiration!
Although it's not really that kind of design i'm looking for..

Update on the progress.
We just started the outside kitchen today. We put the foundation, with root barrier, drainage pipe and old rubble that was still laying here from breaking out some old walls. We evened it out with some gravel and will start putting the stem wall with reused bricks from the property very soon. So that was my call to get into the details of the oven. Decided to make a batchrocket 125mm rmh system underneath the oven, letting the riser feed in the backside of the oven.
I'll make it a fully insulated cob oven with 10cm cob 10 insulation and 10 cob again. Inner diameter 80 cm.
Kind off like how the front of the firebox will look in the design I made. Very curious if I will get the efficiency I aim for here.
Current plans

Hello all!

First of all, thanks for this great place and all the usefull information shared!
Not long ago, I finished my first RMH, batchrocket 150mm with help from batchrocket.eu website and a question here and there on this forum. I'm very happy with the result, but still waiting to do the first real test on the cob to dry completely.

Now, having finished this project, we want to get into building an outdoor kitchen for the community. There's a little natural camping on our property this summer and for that and for us and for who ever passes by, we want to make a natural outdoor kitchen. Ofcourse, this kitchen needs to have a cob/pizza oven. I did a workshop where we built an oven like this but I'm not fully convinced of these smoke 'spitting' unefficient burning ovens while now knowing about rocket science and efficient burning.
I would like to combine the two techniques and make it into a very efficient/fast heating oven. Will also insulate good like with cob ovens. Researching about this combination, I don't find much usefull information or designs. I don't really like the idea of making the fire in the oven space, so hoped to make it below and maybe make a 125mm batchbox burn chamber and riser below leading into the oven (which would act as the bell).
I found a video from 'organic motion' on youtube where they do a similar design but with a J Tube.
Ideally you could light the rocket stove for a while and then when at temperature, close off the oxygen of the fire and cook with the heat that the cob absorbed.
To make sure it stays hot for long and no residues of the fire fall on top of our pizza's, i would probably need a lid to put on top of the whole where the riser is coming into the oven area (think to make that completely in the back of the oven)
I would also add a chimney on the side of the oven with opening as low as possible to make sure the cob  absorbs the heat as long as possible.
I'm sure i'm not the first one having this idea, knowing both rocket stoves and cob ovens are pretty popular.
Did somebody try something out already like this? Or has some proven designs? Etc?
I'm a bit insecure immediately making the oven that way as it's also for guestst to use etc.. but don't want to do 101 test builds maybe with some advise from you guys, I can manage this experimental build!
This is the video of the rocket cob oven I mean: https://youtu.be/DBK5K5HoKRw

Will try adding pics of my rmh build and outdoor kitchen plans.

Thanks ✌️

Thanks for the quick reply's!!
I like the copper pipe suggestion! Might have a look if I can repurpose some, maybe some ceramic blanket in between pipe and rod closes it off nicely, I still have a bit left from insulating the riser.
Thanks Matt for your awesome suggestion! Yeah, makes so much sense the bypass doesn't need to be so big. And your way to close it seems quite nice! I might try to combine that with Peter vdb his suggestion with the copper pipe to 'seal' it nicely.
Thanks for the input guys!