C.Ray Gill

Dave, I know Dr. Hill's name. this is right in my wheelhouse! Good on ya for finding this report! If you get a chance, could you email me the report? Thanks Bruva! I originally started lurking on this forum so I could build an RMH water heater to run my radiant floor system in my home.
Thanks again, C.Ray

I am trying to do the same thing, only with radiant floor heat vs radiators, Borja Diaz. I'll be lurking here to see what develops! Your english is fine, by the way! I hope the more experienced posters here will chime in, as my limited knowledge says you're on the correct path… Bob, I think he's got it close to correct, in a "round-about way"- I believe your thinking is "conventional" vs RMH, which means he's already got what you recommended, if I read your post correctly. He's trying to bring his conventional flame path into the new RMH flame path to conserve fuel...
I've been looking at a lot of the posts here, and I'd recommend you both read as many as you can, I believe most of our "newbie" questions have already been answered by others that were newbies at one time too!

Look @ this post: it's an Outdoor Boiler that is doing exactly what we are trying to do, and he has done a LOT of experimenting for us!
https://permies.com/t/23295/wood-burning-stoves/Secondary-burn-igniting

Sorry, I just got home, I work weird hours. I'll try to get into my shop this week and get pics if I can. It's a REALLY simple slipform that works REALLY well for my application, I hope it helps you with yours!
Cross your fingers & be patient with me and I'll post pics asap.

When I get a chance, I'm going to build a small RMH to experiment with- just wondering if a "scale" model will work well enough to experiment with? I understand that the thermal mass & heat do not scale up & down proportionally, but will I at least be able to try a scale model to get a "feel" for RMHs? Thanks in advance!

Okay, long time Lurker, first time poster. I was hoping to Lurk longer so I wouldn't make my first post sound stupid, but I suddenly realized I won't be alive long enough to sound intelligent!
Long story short, you don't need to use a solid tapered plug in the mold to remove the core: I cast foundry furnaces quite often, and have a 26 guage core that is a slip form. I have a vice grip welded (behind the hinge pin) to the ends of the slip form.
Using the slip form core means that I end up with an (almost) perfectly smooth joint between the "doughnuts" in my furnace to keep from causing turbulence in the flame path. I cast "doughnuts" almost exactly like V1 in Chip Friedline's drawing above (minus the taper, of course).
FWIW, and I have no idea if this will help on an RMH but it seems in my pea brain that this would be an advantage in the Rocket to create more draft in the combustion chimney, I wrap 3/8" vinyl tubing on the outside of the slip form after I expand it, barber pole style, to create a vortex effect around the crucible. I know that there is no crucible in an RMH, but a vortex is a vortex, and creating more draft creates more draft...