Mark Tamp

Gerry Parent wrote:Mark,   Seeing as you are using it just for cooking with nothing to slow or add friction to the exhaust (barrel or mass), the burn tunnel can be shorter without any problems. The ratios are mostly guidelines as there are so many factors with every build that can affect what you can get away with in modifying them.
Have you considered a square tube rather than round? This is what I used for my first RMH build and had an ash tray (made from a recycled cooking oil can) and a metal grate that I made from 1/2" rebar that worked quite well.

Yes I will only use it for cooking, at home but outdoors. The L shape sounds good, would make it easier to make a grate/ash tray. I would prefer using square tube, but the round one is all I have right now. Found it while cleaning at home and that triggered the idea of making a stove.

Glenn Herbert wrote:Rather than depend on the iffy feeding character of a slanted feed tube, I would go with a simple L-tube. A grate in the bottom like Gerry's, or even just a bent piece of metal that gives an air path to the back of the burn tunnel, would help.
A J-tube needs no grate or air channel. A 4" system is small enough that cleaning ash becomes difficult, and an ash cleanout would be needed.

Are you looking for a stationary outdoor cooking stove, or a portable one, or a traveling/camping one? That makes a big difference in what will be most practical.

I want something to use outdoors, and to be able to pick it up easily and store it in a corner of the shed, so looking for something small.



How do the L-tube works? The fire is directly on the bottom of the heat riser? Or you don't put the wood all the way in?

Are there any recommended dimensions or a good specific design for a small L-tube?

Gerry Parent wrote:Hi Mark,   Welcome to the forums.  The ratio 1:2:4 is broken down as follows :   1 means feed tube, 2 means burn chamber and 4 means heat riser. Since all the photos (minus the top middle) one doesn't have a burn chamber, the ratio is kind of irrelevant from the start. I don't have any experience with making a modified L tube like these ones but I do know that I've heard several people complain that they don't consistently feed the wood very well at a 45 degree angle - The wood doesn't slide good and gets caught up more easily than a 90 degree feed tube.
Perhaps someone with more experience with making one can chime in to help you.

Yes that's what confused me, that they have no burn tunnel, even the top middle one seems minimal since the feed tube is at an angle. Maybe they work in a different way, idk I couldn't find much info about them.

I guess the simplest design would be something like this:



60cm x 30cm x 15cm (measured from center line), I would like to have the feed tube closer to the heat riser, but keeping the proportions 1:2:4, results in a really small stove, I am not sure it would work:



30cm x 15cm x 7.5cm, tube diameter is 100mm in both.

And being a circular tube, the J design makes it harder to add an ash tray, and the fuel shell/air intake to the feed and burner tubes.

So, still looking for designs I could try.

I have a piece of 100mm round tube, and I wanted to try to make a small portable rocket stove for cooking, would probably like to use it for 30min to 1h. I know the steel tube wont last too long but I still want to try it.

I would like to make something like these:



But after some reading I found the recommended ratio for the tubes is 1:2:4, and most of these small rocket stoves doesn't seem to use that ratio.

Does anyone know the dimensions or plans for a tested design for these kind of stoves?