Annoucing the Helix – A Horizontal Fed Rocket Heater

We are finalist in the  Alliance for Green Heat Wood Stove Design Challenge sponsored with Popular Mechanics. The contest has been under development for over a year and is set to come to completion on the National Mall in Washington DC. November 15-19th.

Our entry is based on another design developed by Peter van den Berg, the designer or our rocket heater combustion cores.  This heater works like a traditional stove with a door you can view the fire with and a batch loading of the fuel. However it has been married to rocket heater concepts to increase the efficiency of this approach. Several early versions of this heater have been built in Europe and a few in the US.  Below on the left is an example of one installed in a single bell. The photo to the right shows one burning.

Batch Fed Rocket Heater for small masonry heaters

Horizontal Fed Rocket Heater masonry heater. Installed in a single bell.
By permission Ouwehand & Molkenboer

Rocket Heater Masonry Heater Hybrid - The Helix

Burning Horizontal Rocket Heater with Door. By permission Michael Winjnja











Here is sketchup of our entry.

Wood Stove Design Decathlon Entry - The Helix

Helix stove being presented at the Wood Stove Design Decathlon


We have taken this design and optimized it’s flow using computer simulation to increase the already considerable power of this heater. The back of the firebox feeds into a very tall insulated heat riser via a series of specially designed curves and gates. The result is a combustion chamber with internal velocities around 900 mph with a pronounced double helix that serves to mix the gases during secondary combustion in the heat riser.  This was the starting point for our models. The final design is not being released at this time, but you can see how exhaust gases flow.

Helix air flow pattern of Horizontal Rocket Heater

Helix air flow pattern of Horizontal Rocket Heater


These heaters burn hotter, about 100k BTU’s an hour so it is easier to produce more heat faster. The big bonus is that you get to view the fire. On the downside they are much more expensive to build. The castings are much larger and the door and ash tray add to the expense. We will be offering these combustion chambers for sale in late November 2013.

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  1. I want one! But first I need my own home to put it in…1-2 years is my expected install date. Get this perfected and send me your design ideas. I definitely want one of these!

  2. Ted Fogarty says:

    Excited to see this idea in production, some of the aesthetics of a fire are lost in traditional RMHs.

  3. Hi, do you think handicapped people can handle this stove? Seems to be easy access but what about cleaning ashes?

  4. I am very interested in seeing your progress and any literature I might acquire would be appreciated. thanx for your time.

  5. Is this a kit or a total DIY?

    • SMathieu says:

      The Helix is not available from us yet. When we do it, the offering will be a cast core with optional kit to build a particular heater with the core. We anticipate working out a design and so forth this summer.

  6. I am no longer positive where you are getting your information, however
    great topic. I needs to spend a while studying much more or understanding more.

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  7. I am very interested in developments of this design. I assume they will come out in the newsletter, which I have signed up to receive.

  8. MKrepel says:

    I question your velocity figures for this design. I think it very unlikely the gases are traveling above the speed of sound (at sea level). I don’t doubt that the velocities are much higher than many wood burning devices. I think most wood stoves are probably moving the gases at about 10 – 15 feet per second which is around 10mph. I gut feel is that 90mph is very high for this kind of thing. Is it possible that you have the decimal point in the wrong spot?

    • MKrepel says:

      Oops! The beginning of the next to the last sentance in my last post should read, “My gut feeling…”

    • SMathieu says:

      The figures are directly out of solid-works modeling.

      • MKrepel says:

        My apologies.

        I looked up the speed of sound at 1500 degrees-F and it is about 1800mph. I was thinking about Mach 1 at standard sea level temps/pressure. 900mph still seems high to me, but at least it is not beyond the realm of plausibility.

        I have seen Peter Van Den Berg’s work on this style of stove and the results are very impressive.

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    webpage presents quality based posts.

  10. Thank you for putting out such easy to follow information on this exciting technology. Your contribution to innovating the Rocket Stove is inspiring. I’m particularly interested the 8″ Castle build w/ oven and bench and the Helix w/ oven and bench. What is the status with the Helix? I really want a glass viewing door into my fire. I don’t see that for sale on your website yet? I’ll be using this to retrofit an old house and replace a defunct Rumsford Fire place that is centrally located (1800 square feet of home to heat, two floors.) Can the Bells be placed in any footprint I like (as long as the flue flow progresses properly?) I am trying to layout the footprint into my home so my fiancé can conceptualize our future heater. Also, is there any research into adding a third Bell? And what is the feed back from folks who have add a thermal mass vernier to the Dragon Heater build (rock, brick, plaster, tile,) is there a thickness that is best, does adding thermal mass to the Castle allow more heat storage from a firing? How has the mortar held up from years of firing? Any help you can be to answering these questions is most appreciated. Thank you again for all the great work you’ve already done!

    • SMathieu says:

      We have not invested all the time it would take to sell the Helix. We do not have a timeframe on when we would spend the time. Part of the time required is to develop the viewing and the loading door offerings.
      The bells can be placed in any configuration which maintains the exhaust flow. The temperature of the exhaust after the second bell would determine whether a 3rd bell would work. If you have a single wall stove pipe passing through your living space in a room with a tall ceiling, that is usually enough to lose the remainder of the heat.
      Yes, adding thickness to the walls does allow more heat storage. It also makes it take a long time to heat the room starting from cold. So, it would depend on your daily schedule. The fireclay mortar used to fill the cracks between the chimney flue liners is designed to hold up for years.
      If you want more information about the Castle Build, go to the website and fill out a Contact Us form to ask for it.
      Thank you,


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