New Build Questions for Reverse Flow Smoker

[ewilly]

I am in need of some help with definition clarity for a set of calcs that I have generated.

1. Is the firebox intake square the size of the door?
2. FB Intake area definition?
3. What is the count of intakes?
4. If I cut a throat with straight line on top and radius on bottom can someone give me a dimension for the chord length on the top with a 23 inch diameter to accomplish a throat size of 48sq inches

Can anyone verify if there is a strong argument for insulating the firebox.

Thanks for any and all help.

[Big T]

1) No. it's the shape of the air intakes on the fb, either round holes or a square opening. 2) That is the total number of square inches (48) that the opening needs to be. 3) This is the number of intakes needed of that size. If you make them larger the number of intakes will go down, smaller will go up. I like to have at least 2 intakes on opposite sides of the fb so I can adjust them if wind starts blowing in one of them. 4) Pete has several calculators at the top of the page, one of them is a throat shape calculator that can give you the dimensions of a half moon opening. 5) There's a few benefits of an insulated fb, 1) safety, the outside doesn't get as hot, great if there's kids around. 2) fuel consumption, doesn't burn quite as much due to the lack of heat loss by wind or cold air against the fb. If you live where it gets cold for the winter and you plan on using it a lot, it's probably worth it. I live in lower Alabama and it doesn't get very cold for long so I don't insulate them.

[ewilly]

Excellent - so my FB Intake area is 18 sq in and count of .18 intakes which I presume can be interpreted as 1?

I found the throat shape calculator and I think one of my only other question is does position of the BP below the centerline have much effect? Is 3-4 inch below CLine and door opening work?

I am in Central AZ so I think I will forego the insulated FB also.

[Big T]

If you need 18 sq in you could do 1- 3''x6'' opening or 2- 3''x3'' openings. The .18 means that your intake opening is roughly 5 times larger than required. Yes 3''-4'' below the center should be fine. You can have an area larger than the throat below the BP but it can't be smaller than the throat.

[Rodcrafter]

What BigT said.

[Frank_Cox]

yep, as always, BigT nailed it