#263153 - 09/02/13 09:10 AM
rocket stoves and dakota holes
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Rapscallion
Carpal Tunnel
Registered: 02/06/04
Posts: 4020
Loc: Anchorage AK
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Seems to me after much study and little practice that there's a common principle that can be used here in a survival situation.
I've dug a couple Dakota holes, with unremarkable results. Wet soil sucks the heat out of a Dakota hole fire. But as I consider how I had seen a Dakota hole is supposed to be, I think maybe the idea of a rocket stove might make more sense in the future.
The idea of getting the fire to draft such that combustion is more complete (less smoke, more heat) has me reconsidering the way I will try and build the next Dakota hole fire. I think next time I will dig into a mound, or mound up my dirt around the chimney hole, and cut my draft hole at an angle, and so the opening is below the top of the chimney as much as possible, but within reason. It might take it a bit to get the burn chamber idea working in cold soil. But I bet once you get it drafting well, you should be able to build up quite a bit of cleaner heat.
Hmm, all this studying is giving me all sorts of ideas. I got a stovetec sitting in the garage and haven't tried it yet. Maybe I should consider playing around with that thing for a while. I wonder what happens if you make the chimney output hole longer. I bet it will improve combustion, up to a point that is.
It seems there are really two versions of rocket stoves. Those like my little stovetech, which are really just primary burn chambers with a horizontal feed, and a more robust design with something like a refractory chamber where the combustion gases get superheated and result in a more complete combustion. The little ones tend to make a lot more soot. Whereas the ones with the chamber tend to burn quite clean, produce more btus per fuel consumed, but are not altogether as portable.
I don't play with fire near enough these days. I used to be quite the pyro back in the day, but working at a desk has dimmed the spark a bit.
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The ultimate result of shielding men from the effects of folly is to fill the world with fools. -- Herbert Spencer, English Philosopher (1820-1903)
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#263154 - 09/02/13 10:38 AM
Re: rocket stoves and dakota holes (stovetec real)
[Re: benjammin]
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Enthusiast
Registered: 09/10/08
Posts: 382
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It seems there are really two versions of rocket stoves. Those like my little stovetech, which are really just primary burn chambers with a horizontal feed, and a more robust design with something like a refractory chamber where the combustion gases get superheated and result in a more complete combustion. The little ones tend to make a lot more soot. Whereas the ones with the chamber tend to burn quite clean, produce more btus per fuel consumed, but are not altogether as portable.
stovetec is a real rocket stove (Winiarski Rocket Stove), it has an insulated combustion chamber made from refractory ceramic -- they (aprovecho/stovetec) invented the rocketstoves Dr. Larray Winiarski at ETHOS2012 Combustion and Heat Transfer in the Rocket Stove (pdf)Test Results of Cook Stove Performance
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#263155 - 09/02/13 11:14 AM
Re: rocket stoves and dakota holes
[Re: benjammin]
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Geezer in Chief
Geezer
Registered: 08/26/06
Posts: 7705
Loc: southern Cal
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When I have really, really needed the light and heat of a fire, I haven't had the time, energy, or inclination to mess around with a Dakota hole. Just assemble awind break and get the darn thing lit....
and I am a professional digger....
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Geezer in Chief
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#263160 - 09/02/13 04:10 PM
Re: rocket stoves and dakota holes
[Re: benjammin]
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Veteran
Registered: 02/20/09
Posts: 1372
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a good reminder to me. the "dakota hole" was somewhere on my list of techniques to try out ... just didn't get around to it. i need to give it a try. the "benghazi stove" is on the same list - but requires some care :-)
Pete2
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#263169 - 09/02/13 06:24 PM
Re: rocket stoves and dakota holes
[Re: Quietly_Learning]
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Rapscallion
Carpal Tunnel
Registered: 02/06/04
Posts: 4020
Loc: Anchorage AK
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That's a good link. As I say, I want to construct one with a taller chimney, to see if the extra height will help improve combustion.
I am thinking that the diameter of the holes needs to be minimized as well, to aid with vortexing the draft and also improve the combustion process.
I'll have to give this a try sometime. If it works, then I won't have to worry about packing any sort of portable rocket stove all the time.
_________________________
The ultimate result of shielding men from the effects of folly is to fill the world with fools. -- Herbert Spencer, English Philosopher (1820-1903)
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#263176 - 09/02/13 11:01 PM
Re: rocket stoves and dakota holes
[Re: benjammin]
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Veteran
Registered: 02/20/09
Posts: 1372
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i hope that someone will take this topic and "run with it". it would be really helpful if someone spent some time digging Dakota firepits under various conditions, seeing when they work (and when they didn't), and then gave us a good summary.
the same thing applies to rocket stoves.
i'll try and do this for Benghazi stoves.
we need more posts on this forum where people take a very specific topic, run it to ground (with lots of tests), and report their results.
cheers, Pete2
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#263182 - 09/03/13 04:22 AM
Re: rocket stoves and dakota holes
[Re: benjammin]
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Rapscallion
Carpal Tunnel
Registered: 02/06/04
Posts: 4020
Loc: Anchorage AK
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I'll do a little testing on both as time allows. I won't be able to dig up the backyard, but if I can get out in the woods a bit with some time, I will work on the Dakota hole idea. Rocket stoves is just getting some bricks and some stove pipe and a garbage can. I'll get supplies on payday. I'll have to round up some wood as well. Maybe I can scrounge around the woods here. It's been raining heavily all day today, and things are pretty sopped, but I got a few dry sticks in the garage.
_________________________
The ultimate result of shielding men from the effects of folly is to fill the world with fools. -- Herbert Spencer, English Philosopher (1820-1903)
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#263188 - 09/03/13 01:41 PM
Re: rocket stoves and dakota holes
[Re: benjammin]
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Carpal Tunnel
Registered: 08/03/07
Posts: 3078
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I am quite pleased with my Ghillie Adventurer stove. It will boil 1.4 litres of water in 4-6 minutes using a stick of fatwood and some pine cones, twigs etc. It is very efficient and generates little smoke. The fire base also makes an excellent wind shield when using a Trangia burner for conventional cooking. A 500ml Trangia fuel bottle fits nicely in the chimney along with fire tinder, fire steel, cook kit, pot grippers, Trangia burner and fatwood sticks etc when packed. Using some Lumpwood charcoal at Kingsbarns beach at night to make some hot chocolate on an overnight fishing outing. Dakota fire holes have limited use in Scotland due to the potential to start an underground peat fire. I just need an additional cork and the kettle could also be used a 1.4 litre water bottle carrier as well. Edit ...should have been 1.4 litres rather than 1.7 litres
Edited by Am_Fear_Liath_Mor (09/03/13 03:30 PM)
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#263191 - 09/03/13 02:43 PM
Re: rocket stoves and dakota holes
[Re: Am_Fear_Liath_Mor]
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Geezer in Chief
Geezer
Registered: 08/26/06
Posts: 7705
Loc: southern Cal
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What is the weight of the Ghillie Adventurer, unloaded?
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Geezer in Chief
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