Cat797
is one Smokin' Farker
I have previously had a 120 gallon smoker that I built from a propane tank with an insulated firebox. I used Feldon's calculator for my measurements. Here are my thoughts:
Your openings (air intake, FB to CC, between RF plate and bell, and Exhaust) should be bigger than the calculator says; not much, but maybe 15%-25%. The reason for this is to help with the draw. You do not want a bottle neck anywhere in the flow.....now, that's not to say that if the calculator says a 5" chimney 24" tall, that you want to put a 60" tall stack on, cause that's not the answer. However, IMNSHO, you do not want smoke to "stay" in the cook chamber. You also want your fire to go as hot as you want and to burn clean. Having some leeway on the size of your openings gives you that flexibility.
Also, on the FB end in my cooker, the RF plate was maybe 3" from the cooking grate. It doesn't make that big of difference. And, make sure you move the firebox up high enough in the cook chamber to be able to leave a 1" or so amount of material to prevent grease from running back into your firebox in the event of some catastrophe. She will become a raging inferno....
Here's a pic of my cooker, and I'm happy to discuss it further if you'd like......I documented the build on another forum, and I can share the link with you if you want.
All the best,
Ed
Your openings (air intake, FB to CC, between RF plate and bell, and Exhaust) should be bigger than the calculator says; not much, but maybe 15%-25%. The reason for this is to help with the draw. You do not want a bottle neck anywhere in the flow.....now, that's not to say that if the calculator says a 5" chimney 24" tall, that you want to put a 60" tall stack on, cause that's not the answer. However, IMNSHO, you do not want smoke to "stay" in the cook chamber. You also want your fire to go as hot as you want and to burn clean. Having some leeway on the size of your openings gives you that flexibility.
Also, on the FB end in my cooker, the RF plate was maybe 3" from the cooking grate. It doesn't make that big of difference. And, make sure you move the firebox up high enough in the cook chamber to be able to leave a 1" or so amount of material to prevent grease from running back into your firebox in the event of some catastrophe. She will become a raging inferno....
Here's a pic of my cooker, and I'm happy to discuss it further if you'd like......I documented the build on another forum, and I can share the link with you if you want.
All the best,
Ed