The concept for my arch top vortex fire box came from watching these videos of conventional wood stoves injecting massive amounts of preheated air.
On my first heater there are air inlets at both rear bottom corners. They can get blocked by ash so on my second heater they were moved to the top rear corners. One of them goes directly into the fire channel. On my 3rd and all following heaters the air will come in through 8 holes equally spaced on each side at the bottom edges of the arch top. Like the above stoves I want as much combustion as possible to take place in the fire box. I have included a picture of how a large vortex forms in my arch top fire boxes. The fire goes up one wall over the arch and down the other wall. I will get a better picture of this huge vortex soon. I am also showing a picture of the double vortex in the bottom of the riser. That same picture shows the riser to be perfectly smoke free. To my complete surprise another builder just said my fire boxes were too big, it's impossible for me to have a double vortex, the preheated air was coming in at the wrong places, the riser is too short, smoke would come out of the riser and go back into the fire box, the masonry shell is too small, its impossible to be burning clean or efficient, and I have never seen a RMH performing correctly!
On Tuesday I will post pictures of the finished second heater. We are going to wait 28 days for the masonry shell mortar to cure before testing.