Sorry - keep butting in on this thread but its all good stuff !
Andrew it all makes sense, from my previous (albeit limited) experience with rockets and I'm very happy to use a system that I know is going to work straight out of the box
One of the things I found accidentally while building my RMH is that a short increase in CSA in the flue slows the flow rate and you get a greater transfer of heat in that section ( I put a 4' length of 6" ducting in an otherwise 5" flue) This means I can concentrate heat in one area which for my purposes was useful. Wouldn't the same be true in this set up ? A slight increase in csa under the hotplates to maximise heat transfer would be useful wouldn't it ?
Also have you found a chimney necessary ? I mean as a chimney rather than as an extravagant vent ......... are the gases still hot enough for a chimney to work and have you found the extra draw provided by a chimney necessary for the rocket to work ?? Again on my RMH (obviously a different thing altogether but still) adding a chimney slowed the flow rate - vent temperatures are very low so there's no chimney affect.
One last question ! - why not a J tube ?? I'm not the best cook in the world and fiddling around poking wood into an L tube seems like an extra level of hassle I could do without
sorry again for all the brain picking