performance difference?

how does the core perform when hooked to a system, compared to an open riser? does the fire burn slower when a barrel and bench is hooked up? does it burn the same? anyone test burned a core before and compare after after? i have been playing with a small cast core riser deal all summer. playing with wood types and sizes, inserts, p channels....... lots of fun indeed. lol even when stoked up full i still get a smoke puff once in a while out of the feed tube.(no barrel just open riser 20") will this get worse if i hook it too a bench? or does the chimney pull enough to stop this?

Well, if the system behind is well made, it should be the same, pretty much.

A 20" riser doesn't sound very tall. What are the proportions of feed tube height to burn tunnel length to riser height (just for reference, heights from top of burn tunnel, length of burn tunnel roof). Also, what is the system size, in diameter equivalent?

The usual recommendation is a 1:2:4 proportional relationship, and if the riser is not at least 3 times the feed tube height, you may experience poor performance. (There are varying ideas on where to measure the lengths, which would result in different finished dimensions.)
A properly functioning RMH will be extracting enough heat from the flue gases that the chimney will not add much draft. The heat riser/barrel system drives the draft, and pushes the rest of the system.

Satamax Antone wrote:Well, if the system behind is well made, it should be the same, pretty much.

thank you for your input.


Glen, this is just a 4.5" toy i tossed together in the yard to play with. the feed and burn tunnel are brick pavers then the riser was cob perilite. the bricks, at tunnel, are covered with the insulated cob mix too. im not to the point of building an entire system yet. accept for that occasional poof it roars very good.

Okay, sized reasonably in proportion to the diameter... it's probably mostly a matter of scale then, as smaller systems are trickier to get working right. They have more surface to volume than larger systems, so more heat loss which makes it harder to get up to good full combustion temperatures. What is the feed tube height in proportion to the riser?

Glenn Herbert wrote:A properly functioning RMH will be extracting enough heat from the flue gases that the chimney will not add much draft. The heat riser/barrel system drives the draft, and pushes the rest of the system.

To me, that's an overly optimistic statement. Ho many people are there around, who have a system of proper lengh and design with no chimney? Who never experience smokeback.

Anyway, a good chimney is always a plus.

4" above burn chamber aka 1 brick.

i thought that flue power was enhanced by it being next to the barrel? giving it a boost upward. i would think this could only help in drafting.