Need help calculating flow and fire box size for BBQ Bomb

[Rick]

That is going to be the Quooolest smoker in the free world! LOVE that ball - The BBQ BALL! wow - I gotta go sit down...

[Frank_Cox]

that sounds like a perfect name for it LOL! "The BBQ Ball"

[k.a.m.]

More questions....The stack pipe is 4 in. and I am going to bring it down to the grate on the inside. Can it be too long? If I have it 30 in. above the top of cooker and it goes down 20in on the inside is 50 in of 4 in pipe going to affect the draft?

pitbull8151,I dance to a different drummer on stacks and placement. I have built cookers with stacks down low and up high to be honest it does not make a difference in my opinion. If the cooker has the proper intake, firebox to cooking chamber opening, exhaust and well sealed it will perform its your job as the pitmaster to learn her. I also figure the stack protruding into the chamber as total length of stack and not volume of chamber. The reason being is the stack is the chimney and once it enters the smaller volume the taller the stack the harder the draft pull becomes. These are just my thoughts.

[Frank_Cox]

pitbull8151,I dance to a different drummer on stacks and placement. I have built cookers with stacks down low and up high to be honest it does not make a difference in my opinion. If the cooker has the proper intake, firebox to cooking chamber opening, exhaust and well sealed it will perform its your job as the pitmaster to learn her.

Like I always say, "it's 50% the smoker and 50% the guy runnin it!"

I also figure the stack protruding into the chamber as total length of stack and not volume of chamber. The reason being is the stack is the chimney and once it enters the smaller volume the taller the stack the harder the draft pull becomes. These are just my thoughts.

I've calculated this both ways and it seems the difference is marginal at best. So i tend to recommend putting the entire calculated length outside the cook chamber and then if the grate height is desired making it adjustable as i mentioned earlier. but just as Kam said. it doesn't seem to make much of a difference.
there was an argument that kam and tom may remember hearing at one point about "stale smoke" from having the stack at the grate height, but i think it is mainly due to operator error.
ok now that being said ... ...
I always wanted to use that smiley

[k.a.m.]

Its good to have choices my Friend. A lot of times I get emails and P.M.'s from builders that are killing themselves trying to stay on track with the paper. They get so involved in the numbers they sometimes forget their ability to overcome little obstacles. I would have chopped all your wood today to gladly give you these pain killers and possible kidney stones. I can honestly say I did nothing all weekend.

[Frank_Cox]

well, that sounds like a GREAT! weekend to me!
EDITED: Sorry Kam, I just relized what you were saying! hope you get better soon!

[pitbull8151]

Another thought on the pipe into cooker. With the flow coming up the outside wall of the ball, if I dont drop it down some I feel it will not perform as a reverse flow and just draw the heat/smoke right out the top.

Thoughts?

[Rick]

Ouch! hope you get on the mend soon k.a.m.

[k.a.m.]

Another thought on the pipe into cooker. With the flow coming up the outside wall of the ball, if I dont drop it down some I feel it will not perform as a reverse flow and just draw the heat/smoke right out the top.

Thoughts?

pitbull8151, if the connector pipes enter the cooker and travel to the top and exhaust there then having the exhaust stack exit at the bottom makes sense for a reverse effect.
If your connector pipes enter the cook chamber and terminate there and your exhaust is also low that does not make a reverse flow. On a pitmaker cooker the exhaust travels up a chute between the back walls the exhaust is placed between the side walls down low so the heat/smoke travels up and then forced back down to the exhaust. I hope this makes sense.

[Smoker Tom]

I gotta roll a little off here.

I would let the stack hang inside the ball about 6 inchs. I don't care for the stack all the way to the grate but thats just me.

In my opinion, you are gonna have plenty of air turbulence when the smoke comes around the baffle plate.

One last thought is that in many ways its gonna cook somewhat like a drum.