Feldons Pit Calculator issue!

[massive meat pipe]

Hey guyz and galz,

I will be cutting my tank in the next day or two, and while double checking my calculations, some of which found on Feldons Pit Calculator, found the Reverse flow opening size is the same no matter what dimensions you put in (according to the pit calculator). Now I'm questioning my pit layout. The more pressing question I have, is what is a good ratio to follow? My tank is 30" X 70", my fire box is 24" square. I am currently planning to put my reverse flow baffle 6" up from the bottom of the tank, putting me just over 150 sq in opening. Think this is enough for that size tank? I would appreciate any feedback.

Thank you!

[massive meat pipe]

Jeez I'm fried...scratch that calculation, not even close...that would leave me with like a little over 90 sq in? My brain hurts...

[Charcuteryan]

I dont know anything about smoke channel calculations. But i would make a couple cheap ones and lay them in there to see which one i liked best with the grate height and airflow. After i found one i liked i would make it out of good steel use that one

[Mikey]

I plugged in the numbers of your tank and firebox and came up with a firebox to chamber opening of 16.78 inches. Keep in mind that pipe that's bigger than 12" is based on outside diameter, not the inside.

[massive meat pipe]

I plugged in the numbers of your tank and firebox and came up with a firebox to chamber opening of 16.78 inches. Keep in mind that pipe that's bigger than 12" is based on outside diameter, not the inside.

So, is that 16.78 inches supposed to be up from the bottom of the tank, or the horizontal line?

[massive meat pipe]

That 16.78 is only an inch measurement. The next block of that calculator says it requires 110.59 in sq. For the FB to CC opening. Huge difference between 16 and 110. This is why my brain hurts! Thanx for workin it out with me, i appreciate another set of eyes.

[Richtee]

That 16.78 is only an inch measurement. The next block of that calculator says it requires 110.59 in sq. For the FB to CC opening. Huge difference between 16 and 110. This is why my brain hurts! Thanx for workin it out with me, i appreciate another set of eyes.

Heh... inches and square inches are different things ;{) 16.78 long leaves you with a 6.56" high opening. Well..if it were rectangular. I'm not gonna break out the chord/circular formulas. I assume the calc has that built in?

[Richtee]

Post #6 "16.78 sq. inches is the total area of the opening if you're planning on using the half moon. It's best to have it up 1" from BDC as that will be a natural grease dam...just in case"

Really? I din't run the numbers, but that seems awful small?

[Mark R]

Really? I din't run the numbers, but that seems awful small?

That would be a 10" x 5" half moon.....if my math is correct. That should work...I think....

Naaa, I just looked. That's what mine is, your'e lookin a a lot bigger cooker!

On third thought, my cooker is 26" X 50" so not that much different.

[massive meat pipe]

By my calcs, and puttin this on visio and counting a square in at a time, not kidding, the actual is 6.85" up, putting the cord at just about 24". I will cut into the rounded end of the tank, at 7" exactly, which will leave me with 1/4" gaps on each side, I can easily fill with the mig. Some of the engineers where I work actually found a calculation for this, and they came up with 6.85" inches high on a 30" tank. For 110 sq in needed, 7" puts me at about 122 sq in. Since I will split the reverse pan and put it on a 1" slope, should be just about right on..I'm hoping Thank you all for the input! I picked up the plasma cutter just a little bit ago, so I'm goin in Saturdy morning! Wish me luck!

[Mark R]

By my calcs, and puttin this on visio and counting a square in at a time, not kidding, the actual is 6.85" up, putting the cord at just about 24". I will cut into the rounded end of the tank, at 7" exactly, which will leave me with 1/4" gaps on each side, I can easily fill with the mig. Some of the engineers where I work actually found a calculation for this, and they came up with 6.85" inches high on a 30" tank. For 110 sq in needed, 7" puts me at about 122 sq in. Since I will split the reverse pan and put it on a 1" slope, should be just about right on..I'm hoping Thank you all for the input! I picked up the plasma cutter just a little bit ago, so I'm goin in Saturdy morning! Wish me luck!

That sounds right to me. .....Danger zone

[massive meat pipe]

I went for it, everything worked out perfectly. Check out the MMP2 thread in stick burners. Thank you all for help!

[Richtee]

I went for it, everything worked out perfectly. Check out the MMP2 thread in stick burners. Thank you all for help!

By golly... whaddia know Good to hear!