throttleing a rocket heater?

[unhippy]

hi...new here with a few questions

i've been doing all the reading i can find about barrel type Rocket heaters and have an understanding on how they work.

what i'd like to know is how throttle-able is a rocket heater....i've seen a number of references to using a brick or tile to control the air going into burning chamber...how much can the fire be controlled or 'banked' before you lose the clean burn effect of the rocket stove?

there is a point to this question but i need to know how much a rocket stove can be controlled before i take it further

[Donkey]

Rocket stoves need to run full tilt all the time. They shouldn't be "stopped down" like other stoves.

The trick is to get the right amount of air into the mix at any given time. To little and the fuel won't burn completely, too much will cool things down, BOTH situations create a smoky situation.
Rocket stoves tend to burn best stuffed full, with enough gaps between the wood to allow in the right amount of air. As the fire burns down, it needs less air to do the job, and so the bricks, tiles, etc.

Some folks have played around (myself included) with air chokes, lids over the feed with a hole and whatnot. The EXACT size hasn't been nailed down yet, but best air intake size seems to be somewhere between 1/4 - 1/3 system size. You want the effect of what a small blower would do, a rush of forced air.. If that makes sense. ?? The fire should burn ACTIVELY at all times.

I've fantasized about automatic dampers that adjust to always create the perfect fuel/air mix, but haven't tried making one yet.

[unhippy]

the reason i ask is that i had a little cast iron coal stove that had a flame/heat path similar to a j tube rocket stove...firebox-sideways-up.

it always fascinated me that it didn't matter what i burned in it, it would run with no smoke out the top of the flue....as long as there was enough heat in the firebox there was no smoke out the top no matter if the damper was open or closed

wood (wet or dry),sub-bituminous coal or plastic all burned with no visible smoke as long as firebox that up to temp.


i was thinking of having a go a building a replica of the little burner i had but with a downdraft barrel type heat exchanger to try to capture some of the heat that was lost up the flue

[unhippy]

picture attached to my last post is a rough drawing of the little stove i was describing...the firebox in it was about 6 inches wide by about 7 or 8 inches long and the flue was 4 inches in diameter