I would like a top loading j tube style rocket heater - cook plate, but I would like good air control and a big feed box.
Would this design be effective... the riser is offset to allow a slight tangent entry for the gasses to form a vortex.
I have made up a model.
I realise it would be more reliable to build one of Peters tried and tested batch box designs but I really want a top loader because I want the fire low to the ground and a hot plate over the riser at a sensible height.
I also think a full size batchbox might be too powerful for my needs?
Fox, First impression to me is that the wood feed cross sectional area being much larger than the rest of the core is going to smoke back profusely. I would agree on your assessment of making a tried and true stove before making any radical changes but why not just stick with a J tube? Nice mock up though.
Well I already have a working J tube but after watching Potty’s YouTube vids I was wondering if I could go with his bigger feed box design that has a lid fitted, his seems to work very well but I would like other opinions before investing in a new build.
I had planed to build the feed box from refactory cement and the other aspects from ceramic board, my present fire takes quite a long time to get really hot so I was hoping for a faster warm up time as well as a larger feed chamber.
I am more or less retired now so I have time on my hands and a good back ground for building things, obviously I don’t want to build something that won’t work.
A J-tube with large feed won't work right, smokeback will be huge, and if you put a lid on it you will never be able to safely open it while burning. What you want is functionally a batch box, so if you want top loading, I would advise duplicating PvdB's batch box design with a top door added. The port venturi is critical to making this work well; a smooth vortex has been reported to not work as well at mixing as the double ram's horn of the standard batch box design.
Thank you Gerry and Glenn, I guess if a large feed box was the best idea everyone would be useing one.
I may re consider a 8” J tube but the chimney cost put me off when I looked into it.
I think that YouTube videos are quite regional, meaning that in America YouTube will auto load a different playlist than France or U.K. etc
Where I live, Pottys Rocket stove vids are top of the list, so I have been influenced by his designs and I have read through the questions and answers to gain further information.
His design, with the big feed box clearly works, but maybe not as well as it come across and perhaps opening the lid does in fact cause smoke back!
I will do more revision on Peters batch box, my main priority is a cooking hotplate and radiant heat in the winter however, in the summer I still want to use the hotplate without producing massive radiant heat.
Thanks Thomas, I think it will be fun working on my own designs but it is certainly helpful to read about all the experts and thier very successful results
I have ordered several sheets of ceramic board so I can carry out my own experiments. (and probably waste my money)
I have experimenting with my own fire and discovered many things but I really need to change the design to progress further.
I will be building a big feed box as I don’t really see an issue with possible smoke back in my outside enclosure where the fire is situated, but more to the point I can see the similar size box working and “very well documented in detail” on Potty’s videos.
Yes a lid (door) is required but is that not the same with a other rocket stove designs?
I have managed to get a half decent vortex spinning in my present fire but I need to develop a tight cyclone effect before I can make any positive judgment.
I believe (or hope) the positioning of the secondary air inlet will make a big difference to the vortex efficiency.
I have also wondered about exiting the gasses at a tangent from the barrel, this might possibly encourage the hot gasses leaving the riser to continue thier circular travel down inside the barrel ( or other circular enclosure) and increase dwell time?
It just a bit of fun for me but I would appreciate any help I can get, I used to work in a very well equipped facility producing vortex settlement units and vortex C02 dissolving units, hence my interest in the design. Befor that I worked in fibreglass mould making and design and before that in the boat building industry. In my semi retirement over the last few years, I have have been building pizza ovens.
I don’t have access to any of the amazing machines or even a decent workshop that I once did but in my retirement I do have plenty of time.
Hi Fox - I've studied ppotty's videos for a while and his latest one seems to work well with a proper glass door.
My 6" workshop J-Tube Rocket has a large feed 'area'. I lined the walls with vermiculite board to make a sort of low 'firebox'. It works really well but I have to use a steel blanking plate to cover some of this 'firebox' or else I would get smokeback. The amount of air that I admit to the fire depends on the amount of fuel and state of the burn. It's also handy for closing down the J when the fire has gone out, so retaining the heat in the mass of my brick bell.
An added bonus of this arrangement is that the steel plate acts as a small radiator and gives off a lot of heat. It is fitted with a cool touch handle so it can be adjusted without having to wear gloves.
Thanks John, I have spoken to Potty via YouTube, he is confident that an even bigger fire box would be fine.
I am going to build the box from cast refactory and the rest from ceramic board ... just waiting for my order to arrive....
Do you have any pictures of your stove?