Anyone know about rocket stoves?

[tomme boy]

I made a small rocket heater out of a couple propane kegs. I am feeding it wood pellets. I have a pretty good pellet basket made up and is dropping ash and burned pellets well.

I am having another problem. It stalls. Or stops rocketing. There is a ton of wood gas flowing into the burn chamber. Sometimes it starts back up. But other times you have to give it a little puff of breath. Then it starts rocketing. The burn looks really good. It almost all white to a blue flame in the chamber.

Can't figure out what is going on. If I don't get it started back up, it puts itself out.

Too much, or not enough air??????

[rush1886]

Stab in the dark here; lengthen your flue just a tad. Will give the whole thing a bit more draft, hence a bit more combustion air.

Tons of info on these things on you tube. Do you have adequate air into the pellet box from underneath? Again, with pellets being somewhat compact in nature, perhaps a smaller fire window in the burn box. In other words, close off the area where the burn shelf is exposed to the draft shelf,, just a bit. Same basic principle as lengthening the flue, but concentrating effort in the actual burn area.

Hope that makes sense. Does to me, but then---------!

[tomme boy]

Well right now I have it outside playing. I have I think 13' of flue with no cap. The way the burn basket is made is it is raised up off of the chamber tube about an inch. That way the air can inter under the basket and swipe away the droppings. I also have a piece of stainless sheetmetal bent into a channel that gives a 3/4" air inlet to the front of the basket.

I built this one so it is a j tube with a front inlet to light and adjust the air also. I used 4" sq. tubing. I think today I am going to cut open the bottom under the basket and add a sheetmetal drop box for the ash instead of it getting sucked into the system. Just have to wait till one of my friends stop over as my hands are killing me today.

[runfiverun]

the air to fuel ratio is getting out of whack. [yeah I know obvious]
I'd say your running out of air but you could just be not getting the right amount of fuel under certain circumstances.
I'd try building a little more air availability into the system and add a dampener to control it then you could tune things a little bit.

in my old wood stove I burn coal on occasion and generally have to put a fan at the base of the stove to help things along, I added a bit more flue pipe to increase stack velocity this summer so we will see how that works.

[tomme boy]

Well playing around today. It looks like it wants more fuel. I built a drop box under the basket to catch the coals and to increase air under the basket. Made it worse till I threw in a bunch of pellets and lit them on fire. Man this thing was cranking after that. So, I think I am going to cut off the 4' feed tube and replace it with some firebrick and make a 6 or 8" chamber about 12" long feeding into the 4"riser tube.

[Silvercreek Farmer]

Gonna smelt with it?

[tomme boy]

No. Proto-typing to an actual build for a outside boiler to help heat house. Its just a crudely put together one right now. Trying to find out what does and does not work.

Going to try to round up parts this coming summer for the boiler part. Already located the heat exchanger and fan for the house.

[labradigger1]

How about some pics tomme

[tomme boy]

This is what I have so far.

http://img.photobucket.com/albums/v21/tommeboy/Mobile%20Uploads/IMG_20151222_095711_567_zpsdobiccco.jpg (http://smg.photobucket.com/user/tommeboy/media/Mobile%20Uploads/IMG_20151222_095711_567_zpsdobiccco.jpg.html)

Here are a couple pics of the burn basket for using pellets. So far this one is working OK at best. Getting the spacing of the rods is really important. I have started to bend them a little to help them to drop out the burned pellets and ash.

http://img.photobucket.com/albums/v21/tommeboy/Mobile%20Uploads/IMG_20151222_095657_289_zpsjpybgsz4.jpg (http://smg.photobucket.com/user/tommeboy/media/Mobile%20Uploads/IMG_20151222_095657_289_zpsjpybgsz4.jpg.html)

http://img.photobucket.com/albums/v21/tommeboy/IMG_20151222_095646_490_zpsgglan2f5.jpg (http://smg.photobucket.com/user/tommeboy/media/IMG_20151222_095646_490_zpsgglan2f5.jpg.html)


The basket slides in from the horizontal tube so that it lines up with the angled feed tube. There is a little over 3/4" under the basket to help make the pellets burn.

On the bottom I riveted together a ash box. I cut a 2''x4'' hole under the basket to add more air and for somewhere for the ash to drop.

Once I built a small fire in the ash box, this thing took off like crazy. It sounds like a V1 cruise rocket.

[MUSTANG]

Tommee Boy:

Have been interested in rocket stoves for a few years, but have not built one yet - nor will I spend the $$$ they seem to want at a couple of the Camping Stores & Flea Markets where I have seen them. Are you hand feeding the stove? That has been one of the draw backs I've seen for their use.

With wood pellets, one can use an auger to feed the pellets (if you have electricity). Local fire place store has a Wood Pellet Stove that is gravity feed and does not require electricity. You can see info on line for one at: http://gravityfeedstoves.com/the-stoves.html

156173

Be interesting to see if the Z feed arrangement might work with your rocket stove set up.

[tomme boy]

I have a hopper to feed the pellets. It slides into the vertical tube about half way in.