Smaoker Math and FB to CC ?

[svaillan]

Hello all. Here is what I have so far for math on a RF 124gal tank build.

124gal Tank
24 1/4" wide
12 1/8" Radius (or 12.125)

Cooker Chamber Size 28644.00
Recommended Firebox Size 9548.00
Recommended Chimney Volume 494.00
Recommended Air Inlet Area 29.64
Recommended Firebox-to-Cooker Opening Area 79.04

I tried using this excel sheet for figuring out the FB to CC opening. Or the moon cut.
http://webpages.charter.net/tomchis...opy of Firebox opening - curved_Simple-1.xlsx

But I don't get why the 3 sections to it. What I am trying to accomplish is to have the fire box notch on the end of the 124gal tank lower then the center axis and still allow the proper size opening (1/4 moon cut). That way my heat plate across the bottom of the tank has some room between it and the cooking ranks which I would like to be at center axis.

Once I know how wide that moon cut is I'll know how deep to go with my firebox. From there height and width should be easy. Also I posted the question earlier of does the area in the firebox below the fire crate count toward total volume. I believe it does but I want to make sure. Thanks Steve

 

[outwest]

Try googleing Feldons fire box calculator. I have used his twice to build my reverse flow cookers. The formula you have is a bit confusing. but with feldons you will need stack size as well. if you need more help pm and i will help you out.
Link to BBQ Pit Calculator

I used your tank size and made some guess as to what your stack and intakes would be so hope this helps you.

Your half moon opening would be just about 15 inches so it would be about 7.5 inches tall by 15 inches wide if that makes sense.

 

[Bludawg]

this is easier than trying to give you a trig lesson
http://en.wikipedia.org/wiki/Circular_segment

 

[Yellowhair42]

I think you are confused. There is only one smile shaped cut out from FB to CC.

 

[svaillan]

Yellowhair, the 2 cuts are the moon shape in the firebox and the notch that I take out of the propane tank. The lower the notch or less of a notch in the tank the more cooking area.

 

[Yellowhair42]

You only need the sq. inch area of the opening. It can be any shape as long as it's the correct size.

 

[Bludawg]

The easiest way to to do a RF is to cuts a 90 deg piece from the tank then build the fire box, cut the opening in the back of the firebox as a rectangle, make the top of the firebox the RF plate slide it in and weld it up.