1 gallon = 231 cu in
80 gal = 18480 cu in
by my calc anyway
Ok this is my best guess here.
The tank is18483 cu in.
1/3 of that is 6160 cu in.
Making the firebox size of 18x18x19 come in really close to that number.
The stack needs a number of 307 cu in, so using the 2x4 square tube you will need a total of 42 inchs. Can be one or two stacks.
The firebox air intake needs to be 24.51 sq in.
How ever you want to add it up will work. Dial vents or sliding vents, doesn't really matter.
The firebox to cook area says it needs 49.25 sq in.
Again this one is kinda what works for ya.
4-4" pipes or
I would recommend making a 7" x 7" square, could be made from the material you already have or could be bought.
Now on the two drums that I built with the firebox not attached I used 4" pipe.
One had a 4" stack and one had a 2" stack.
They both cook very well.
I would say that these numbers are to get the best results, the biggest bang for your fuel.
My vote is going to have to be,
That you follow the numbers halfway close until you get to the firebox to cook area connection. Use two 2x4 tubes from the firebox up to the cook area. Thats 16 sq inchs, my drums are 4" and thats 12.5 sq inchs. You will have more air flow then mine.
The firebox size is not set in stone, it can be changed to any shape that adds up to 6160 cu in. Make it what ever size works for the space you are using.
You can always damper the stacks if there is to much draw.
And worse case, if you can't get enough heat you can easily add another 2x4 tube from the fire to cook area.
Once again, I am not sure if the calc is set up for a RF or not. This could be why the numbers are a little off.
I say run with it, build it with what you have and if its not perfect then just adapt and overcome.
Remember this is a smoker, not the space shuttle.
Hey Tom, I found this site http://www.calculatoredge.com/enggcalc/volume.html#cylinder
Maybe it will help someone in the future!
ok my buddy seems to think that we could have 2 pipes comein from the fire box to the smoke chamber an by doin that we could cook ribs on 1 side an a butt on the other side....he thinks that we can controle heat temps for each side like one side be around 150 an the other side bout 250????sounds kinda jacked up to me what do yall think good idea or not???
Sweet start bro,have you got your plate for the firebox?I see you got plenty of fuel and my favorite cold beverage.have you decided on exhaust style/size yet.I am in the process of gathering parts to make 4 uds smokers and then if I can get my hands on a certain 250 gallon tank,I will be making a small trailer unit.keep it up bro....