Woodgas stove question!

[dazcon]

I made a woodgas stove for out and about, but i wasn't getting much in the way of jet flames from the upper holes. Pretty feeble really, so i wondered what the optimal sized holes are? The cans fit nice and tight, so i think the problem must be either the hole size or configuration.
Any help from people experienced in these matters is much appreciated.
Here are a few pics.

Thanks!!

Darren.

 

[nitrambur]

In picture 3 it looks like your outer container has an open bottom

 

[dazcon]

I didn't think that mattered! If anything it will just let in more air won't it?

Darren.

 

[mrcharly]

My understanding of these stoves is that the outer must be sealed - the inner should have holes in the bottom.

The partly-combusted gases given off get drawn down through the fuel and through the holes in bottom of the inner can. This then flows out through the holes at the top of the inner can and ignite there.

Holes in the outer can will prevent the 'gassing'.

 

[nitrambur]

I've never made one, so I'm not totally sure, but all the others I've seen have a sealed base with air holes in the side. I would guess that your wood-gas is leaking all over the place so you wont be getting as much as you expect back round to the top holes of the inner.

 

[dazcon]

I'm still on the lookout for a suitable stainless container for the outer can, then everything will be stainless. I may try to seal the base of this one for now to see if it's an improvement.

Darren.

 

[Elements]

Now this intrigues me.... is there a design around to make one of these or a article with how/why it works etc please?

Thanks in advance
Rob

 

[mrcharly]

See here
http://yacf.co.uk/forum/index.php?topic=35564.0

for a description of one an acquaintance made.

 

[Teepee]

Well done on the stove

If you stand the stove on a sheet of flat metal etc, you will effectively block the base and you can see the results instantly. It will make the flames die down and the stove will burn slower. You will need more top holes and more holes in the bottom of the outside can. You are trying to get the incoming air to flow through a space that neither widens or constricts, this will ensure the best possible air flow.
You can work this out accurately if you want from the size of the cans and the space that it leaves between the inner and outer cans using Area of a circle=3.142 x radius squared. Time to either break out the bushcraft calculator or drill and hope.

 

[Teepee]

More than you ever wish was written about these stoves by people who really know how they work; It's in depth though.

http://www.bioenergylists.org/tludhandbookdraft-1

 

[dazcon]

I finally got round to working on the stove today. I made all the holes a bit bigger and even added a few more. Tested it in the garden on a metal plate and it's vastly improved. Pretty impressive gassification this time. Boiled the full kettle in 7 minutes!!!
Thanks for the help guys!

Darren.