Bman’s Bits: Rocket Stove Demo

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22 Responses to Bman’s Bits: Rocket Stove Demo

  1. Bman says:

    By the way, you can use just about anything as fuel. You dont have to use charcoal briquets.

  2. sortahwitte says:

    As soon as I saw the pbr, I knew this was an authentic Bman post. You just can’t be too careful.

  3. R.D. Walker says:

    I finally got a chance to watch. Great vid my man.

  4. Jim22 says:

    “A night of Pabst…” I’ll use that.

    The burger will be good. I can predict it.

    Only thing I’d say would improve it is to use steel duct pipe. That looks like aluminum. It won’t last as long.

    Good job.

  5. Bman says:

    Good point Jim. I should’ve mentioned that. The part that I showed was aluminum, however the part in the stove is steel. I use the other piece for the top, like a smoke stack for heating purposes on the Pontang. It works great for that too.

  6. notamobster says:

    You are the fucking man, Bman! I love it. I made a rocket stove from a green bean can and some tomato paste cans with steel tape.

    It couldn’t get enough air to stay lit, but the kids and I had a blast with it!

    You rock!

  7. Jim22 says:

    I’m thinking five gallon bucket with a six-inch diameter fire chamber instead of four. I think it would make more heat from bigger fire. Probably wouldn’t need a metal bucket.

    What about a draft control on the end you put the fuel in?

  8. Bman says:

    Thats a great idea, Jim! One issue I have is the buildup of ashes over time. I need to figure out a way to remove the ashes without distubing the flame. If the ashes build up too much, it blocks the air intake.

  9. Jim22 says:

    I would do what they do in wood/coal stoves: Make a grate for the fuel to lie in. If it’s full of holes or made from several bars the ash will fall through and can be removed without disturbing the fuel.

  10. BaconNeggs says:

    Thanks for the video Bman, very inspiring from the Pabst blue ribbon man. Hahaha.

    I think I shall have to get my two boys to make a cookout with me, using some of the cans we currently recycle, they will be amazed.

    Its a great fun way to teach an important survival lesson and grill some burgers or dawgs.

  11. notamobster says:

    Bman – use your metalworking skills to combine two elbows – juxtaposed 180 degrees from each other. Cover one side as a clean out. Or you could make your next stove out of bricks like my other video shows and be able to reach in and clean that sucker out.

    Don’t forget the swedish fire torch! Awesome. Put your little metal grill on there and you got a portable grill. The rocket stove is useful if you just have twigs to burn. Just some thoughts.

  12. Locke n Load says:

    Loved the video dude, well done. Like the burger.
    Dumbass question, but couldn’t you amplify the intensity of the flame by stacking smaller vented cans for the burner and creating a venturi effect? I mean, I know its combustible gas thats providing the heat, but doesn’t flamable gas act like a liquid? Wouldn’t that work like a torch?

  13. Slaphappypap says:

    Solid Bman! Looks like you’ll be eating burgers/dogs for awhile. Just for the fun of it.

  14. notamobster says:

    Locke – the venturi nozzle requires pressure on the input side (see rocket exhaust venturi). Otherwise, it’s just a restriction.

    Bernoulli’s principle applies in fluid dynamics, whereas the same idea is expressed in the form of turbulence through a gaseous venturi.

    The convergent inlet of the venturi forces the slow of liquid in fluid dynamics and air in aerodynamics.

    An increase in pressure results in a slowing of flow – in either case – it is through the rapid expansion of the divergent outlet that flow increases and pressure drops. You can’t produce this without some means of back-pressure which is anathema to the idea of the rocket stove.

    The rocket stove relies on the smooth, unfettered influx of laminar airflow. It’s basically just a more efficient fire because the increased oxygen allows for the burning of the hydrogen & methane off-gases which are the natural biproduct of the oxidation and decomposition of wood.

    If you put a chokepoint (venturi) prior to combustion, you lose airflow, defeating the gasification. If you put a venturi aft of combustion, you will force the pressure differential out the inlet (which must remain open), thus defeating the purpose – gasification.

    You could increase oxygen further by increasing turbulence prior to combustion – but that’s a tough line to toe. Also, you don’t want to invest a lot of time or money in the process, as this is a cheap, simple cook stove. Once, you’ve invested too much time or money it is no longer cheap or simple.

    See, RD, I like science, just the technical (mechanical) sciences. My nerd creds remain intact. 🙂

  15. notamobster says:

    You could achieve the desired effect by using something I’m sure your asiaphile ass is familiar with – a collar that is slightly larger than you pans cooking surface.

    It creates a venturi by using your entire combustion can area as the throat of venturi (but with no convergent inlet) and the collar becomes the (non) divergent outlet, increasing the speed of the exhaust gas outlet through rapid expansion, but directing it up the side of your pan.

  16. R.D. Walker says:

    Never doubted you for a second.

    I can’t believe nobody even acknowledged the benefit of my foot bellows turbo booster.

    I didn’t mean that it would be for constant use. Just that it would sure help getting things going and adding oomph when things slow a bit.

  17. notamobster says:

    A rocket stove uses a ton of fuel on it’s own. It burns hot and fast. Increasing input airflow will make it burn faster, using even more fuel.

    I didn’t want to point that out.

    Bellows are used in fireplaces and cook stoves because they are extremely inefficient. gasifiers tend to be 90% efficient.

  18. R.D. Walker says:

    You inspired me, dude.

    It couldn’t get enough air to stay lit, but the kids and I had a blast with it!

  19. notamobster says:

    It might have actually helped with my mini-stove version.

  20. Locke n Load says:

    Outstanding explanation Nota, thanks. Forgot about the pressure, doy. Been a LONG damn time since I took physics 🙂

  21. Jim22 says:

    I wonder if the flow would be increased with a longer chimney. It certainly makes stoves ‘Draw’ better if you make the chimney taller. Sorta like a syphon in reverse.