portable collapsible rocket stove heater/stove/pizza oven

Yes I would agree that since the heat is good outside, the wood doesn't need to "work as hard", like a bbq, it doesn't drop off as quick. But I wouldn't be smoking cheese in there anytime soon!

 

I didn't get around to the hardwood firewood test yet, but I did burn 1/2" x 3" pine boards and packed the firebox, leaving air channels between the stacks. It didn't get near as hot (620 barrel top within 20 minutes of lighting fire, pizza oven 450 an hour after lighting fire) or burn near as long.

Barrel top was down to 340 at two hours and then it rained But there was still fire in the firebox at 3 hours after lighting (last photo.)

 

I rearranged the fire path again and the barrel top got 90 • F hotter, up to 865• from 774• (even though outside temps have fallen to 65• this evening, and prior tests days were hot and sunny in the mid 80s.)

You can see the strength of the natural draft here through the small viewport in the side of the firebox. The flames are moving/drawing so fast they're horizontal.

Edit to add:
At two and a half hours since ignition, barrel top temp is 400• and the firebox is still just less than half full.

 

I finally had a chance to run a batch of hardwood firewood today, a combination of 6 pieces of ash, oak and cherry. The wood was well seasoned but unfortunately uncovered and with recent rains it didn't perform much better, hotter or longer than the (very dry) pine boards, with approximately the same barrel top temps and duration of burn, three hours and 560• on top after a half hour.

The compressed sawdust bricks still hold the record with almost 6 hours burn times and 865• barrel top temps. Wood stove users don't necessarily relate extended burn times with the compressed fire bricks but they sure seem optimal in this rocket stove application and they are the only way I can accurately compare changes in firebox and riser geometry and primary and secondary air adjustments.

 

The second prototype of this rocket stove heater is progressing well. I hope to have this manufactured as a kit, a modern powerful safe and efficient "barrel stove kit."

 

Nice work Brian
I bet that would get you nice and toasty in an ice shanty

 

Progress. (I put it on the back burner for two weeks while my oldest son was home from California.) Secondary air tube assembly is shown inside next to the Venturi port. I still have to weld it up and screw it all together.

 

Lookin good Brian

 

Thanks! Having no background in working with metal, I'm really happy with how it has turned out.

 

Thank you. Honestly, it looks like somebody who knew what the heck they were doing built it. (As opposed to a knucklehead who built this by hand with bargains from Craigslist (including a used 55 gallon straight sided barrel) and Harbor Freight, and had no trips to the ER this time! (My first rocket heater involved falling on outside cement cellar steps and a torn ligament in the wrist.)

 

Grizzly Adam

 

Wow. Very nice Brian!

 

Thanks. Eventually I set this rocket heater up as a back yard heater and plumbed a second barrel next to the first into the exhaust stream and lined it with firebrick.

The exhaust from the rocket heater travels down through the second barrel (which I use as an “Ugly Drum Smoker” or BBQ grill) then exits at floor level and goes up the flue.