Hello everyone. Thankful for this forum. Would appreciate your input.
After what I thought was sufficient research, (yes I have "The Book" lol) and close attention to the proper dimensions,
I started in on my first rsmh -
1 1/4" x 9 x 4 1/2" firebrick lined, three 8" masonry chimney flues - 36" tall.
Burn chamber is (approx.) 7 3/4" tall x 5" wide x 13" deep.
Total burn area is 21" long including the 8" flue width.
Feed tube is a 6x6 rectangle metal tube cut at a 45 d angle.
(This angle was chosen to allow for a self-feeding pellet option at future date).
A 1" high metal grate sits on the brick and fuel then sits on this grate while burning.
Door when open fully allows air into burn chamber opening which is (as above) 7.5"h x 5"w.
Two air intake baffles allow adjusted air in under the 1" metal grate when door is closed.
Burn chamber is insulated 1 1/2 w/Perlite both sides, but not the top or bottom.
Top of stove was not fully sealed. (No gasket material installed yet on the top inspection plate).
Consequently, stove was losing heat out of the top before it could be directed down to the exhaust pipe.
Can be easily rectified with gasket material installed.
Exhaust diameter is 8".
Chimney is insulated with 1 1/2" Perlite all four sides.
Fired the prototype up yesterday.
Stove drew well, little smoke back-up. After 4-6 mins, no smoke out of exhaust flue.
Heat at the top of the chimney was + - 425 d. F.
Stove doesn't achieve that "rockety" sound when burning.
Could not detect the vortex type fire expected in the flue.
Thomas Winters : 90% of all our previous remarks can be thrown out the window, we didn't know you were trying to combine a Cob-Build style Rocket Mass Heater With an All Metal Wood Stove, All I can say is good luck !
A final suggestion, even though I hate most of the Crap that passes for Rocket stove Builds in You-Tube land, you should go to You-Tube, and type web4deb into
You-Tubes search engine, from there you should be directed to the 'web4deb channel' scroll down to the set of rocket stove videos he has put up there!
Again good luck ! Big AL !
Success has a Thousand Fathers , Failure is an Orphan
Thomas, an all metal construction is doomed! Been there done that. Won't last. I burned my first , melting a gas bottle in less than 30 burns. 5mm thick steel getting to the verge of being liquid and bending downwards because of gravity.
Tell us, so we know, are you intrested in making something cool and which you will be able to brag about? Or make a working and clean rocket? As in clean emissions. Metal lined with firebricks, and insulated on the outside is possible for example. Angled feed doesn't give enough turbulence.
Tom, a couple of thoughts.
One, the picture you posted to demonstrate that people have used angled feed tubes seems to have caused some confusion. People are assuming that is a picture of your project.
Two, have you experimented with your airflow by restricting the feed tube opening? Seems to me it would be a really fast test to see whether or not you're getting too much air into the system, which might contribute to lower temperatures and prevent the full "rocket" effect.
Good idea Peter. Yes, I did do a minimum of testing with the air flow. I'll play with the air intake once I get the stove installed with the longer length of exhaust pipe I have planned.
The stove actually achieved 452* as a high temp, not 425*.
That temp was measured on the metal on the back side of the stove at the top of the outershell, not in the heat riser itself.
My guess is the heat riser temp itself was a bit higher.
Also, it was a 90* + temp day, so the draft was not quite as good as it should be under normal cooler/colder weather use.
And the exhaust pipe was only 9" long.
Thanks for your input. T
Rocket Mass Heater Plans: Annex 6" L-shaped Bench by Ernie and Erica