Half of 250 gal rf smoker

[coon8448]

I have a 250 gal propane tank but I do not want a smoker that big. So I'm thinking about cutting it in half and making two smokers so I can sell one to fund my project and I would be able to correct what I don't like on the first one.

My question is has anyone done this I can't find any pictures or information. Cutting it in half would give me a lower cooking area of 30x40 in. It would be more of a square than a rectangle so would that affect the flow of the smoke and heat in a bad way or does shape matter.

Thanks

 

[themule69]

I can't see any reason it wouldn't work.

I see this is your first post. When you get a chance will you drop by roll call so we can all give you a proper SMF welcome?

Happy smoken.

David

 

[coon8448]

I keep seeing something about feldons calculator not being accurate for rf smokers but I have not come across any good information about how to correctly size a fb and exhaust. Any know where I can find information about this.

 

[lendecatural]

This post should answer your questions: http://www.smokingmeatforums.com/t/161795/is-feldons-calculator-really-flawed

Here is a link to the calculator for those numbers: http://feldoncentral.com/bbqcalculator.html

 

[coon8448]

Thanks Len for the link to the thread I hadn't seen that one.  Lots of good info in it.

I still have a question about the cc. If I cut my tank in two I will have a 125gal tank.  So do I put 125gal in for the cc size or is my cc the area above the rf plate?

If 125 is my cc then I put 22x22x21 in for my fb and the size diff is 105%.  (Of course I will probbaly make my fb 24x24x24 and that is 144% size diff)  Will I have any negative effects making my fb that big?

Using the 22x21x22 fb my exhaust should be 4.5" dia and 32" long (which is 508in^3) and I should have an intake of 20.5in^2 (I will make my intake larger) and a throat area of 122in^2 (for the calculator gives 81.3in^2 and 81.3in^2 * 1.5=122in^2)  I will make the opening at the end of the rf plate slightly larger than my throat size( around 127in^2)

This is the link to my numbers

 http://[url=http://feldoncentral.com/bbqcalculator.html?cc=0,0,125,0,0,0,28875.00,9625.00&fb=22,21,22,0,0,10164.00,9625.00,105.6&ch=4.5,508.20,31.97&fi=3,2.5,0,30.49,4.07&fc=10.18,14.39,81.31]Link to BBQ Pit Calculator[/url]

Here is a link to another good thread.  Near the bottom there is a picture with equations on it.  I haven't compared the outputs to the ones from feldon's calculator but I think they will be similar.  These equations find the area under the rf plate. 

http://www.smokingmeatforums.com/t/161765/my-build#post_1171335

What are your ideas on the equations in the picture?

 

[lendecatural]

Yes you would put 125 gallons in the calculator. You must use a fire box in the calculator that is 100%, for the purpose of calculation only, then you build a fire box larger than the 100% size and use it on the cook chamber. The calculator will cause the chimney and firebox opening to be too large if you have a hundred and forty four percent fire box in the calculator.

The formula on Dave's post is very good.

The calculator is easier for some users, but the calculator flaw is you must use a fictional 100% firebox for proper opening size that has to be multiplied by 1.5.

I can't get your link to pull up on my phone I will check it when I get back home tomorrow.