Scott911 McCoy

because the gas expands, and speeds up significantly, I think I do need to measure at the exit of the stove.  I would be feeding cold air into the inlet with my blower at a higher than normal input speed to componsate. 

I would like to tinker with rocket stoves, without the fire. 

In otherwords, experiment with various notions without have the light up a fire, or require testing parts be fireproof, or keep at a distance for observations and measurements.

For example - I'd like to test out a venturie to recirculate some smoke for a reburn.  Without fire, I can make test shapes with paper and plastic pipe, and stick my head right in the pipe to see how it's working if I can avoid the fire part of the rocket stove but still have the draft effect.

So far, I've gotten an infinitely variable-speed leaf blower which I want to blow into the wood feed.  What I'm trying to do now is figure our what speed best approximates the normal draft of the rocket stove while burning.

I figure I need to run and typical fire and measure the flow - probably at the top of the stack (simple cooker design - no bench).  Then match that measurement by playing with the blower speed switch. 

Problem is, how to get first measurement in the fire?... any ideas?

And I see your post count is "one" Wendy - so welcome to the forums! 

I've only reciently discovered this place, and love it : it's filled with so many gifted and generious (with time and knowledge) people. 

& keep us up to date on your projects, I'm personally very interested in cookstoves.

A potential cross-over could be build in both the J and L into the same pipe.

Allow for the top of the "J" to be capped after inserting wood. 
Once cap is in place, the air draw would be forced to come from end of "L"

I would presume this would offer best of both worlds- wood would gravity feed needing less attention, with little to no danger of fire creeping up sticks and smoking room.

thanks guys - I just ordered a copy.

I can't explain why I couldn't successfully preform the simplest search in the world myself - maybe a previous bad search was cached on my compluter and I wasn't getting fresh results or something.  Anyway - thanks again...

I'm only seeing a $100 version on amazon... as an out of print verison.
Can someome provide a link to purchase?  thanks.

nice work M...

has the tube ever clogged? I wonder how much smaller diameter feed tube (so you could get a slower / longer burn) you could get and still have smooth fuel flow with that sized chips. 

hey sebgreen -

One thing to keep in mind is that if you use heavy brick means without insulation, you'll have to be heating up all that mass in addition to your cookpot. 

Your quart of water for tea may require just abit of fuel.  BUT, now remember that you also have to heat up the mass of all that brick each and every time you want to cook something.    That adds to the time and amount of food needed, probabaly several times over. 

I've been thinking of the same type of cooker.

I want to minimize smoke (I have a boy with mild ashma) and am thinking that the butt warming notion of drawing the gasses back down again  - i.e. lengthening the chimney bit - will help.

The big question I have is this:  the black line you show represents a hot plate. 
The normal "cooking" rocket stove has this open - i.e. a grill - the fire is touching the pan.

Not much heat is lost from the pan in your diagram when the pan is not in direct contact with the fire?  Is it alot?  to much to make the down draft worthwhile?  Does the draft action actually steal heat from the "hot plate"?

In the butt warmer - it's ok for this downstream gas to be hot/warm - that's GOOD heat going through the system - still being absorbed by the cob bench - etc.

In the stove, I'm worried it might be wasted heat...

that is nice work.. sorry about the breakage - but the glowing mouth looks kind of cool! 

On next verions maybe you could bore out the mouth or eyes and embed some mica in the clay to it'll let the fire light through.