Philip Baldwin : It depends ! Even which way the wind is blowing on a given day can be a challenge!
Here is the best rule of thumb: 1st you build your system outdoors to prove it works, then you put your barrel on top and immediately come off of your manifold
with a final vertical chimney. This lets you prove that the Rocket base works and any future problems are in the horizontal plumbing or the final vertical chimney
Then you move everything inside and rebuild the Rocket Burner base and come off of your manifold with your horizontal chimney .
With a tall Heat Riser to push the hot exhaust gases and a well drawing Final Vertical Chimney you
should easily get 50 feet of horizontal piping run through your
Thermal Mass
Cob Bench. Remember to subtract 5 feet for every Horizontal Elbow and "T" with clean out . This distance should be long
enough to get the measured
Temperature of the hot exhaust gases down to 120ºƒ to 150ºƒ which is more important than more length which may cool your exhaust too much and weaken your
draw .
As every single
RMH is a one-off D.I.Y. creation that IS the best
answer I can give you and the next guy after you ! For the Good of the Crafts ! Big AL
Late note did you ever give us a your location ? A.L.
