Advice needed for reverse flow smoker!

Discussion in 'Smoker Builds' started by anderjes, Mar 22, 2015.

  1. Hey Everyone Im new to this site. Ive read many different threads on here and got a ton of info from everyone. Im currently on my 2nd smoker build. Im buulding a trailer mounted reverse flow smoker. I have a 320 gallon propane tank. Dimenisons 30in diameter by 10 feet long. Ive done the pit calulator and came up with these numbers.
    Cook Chamber Size
    24640 cubic inches
    Fire Box Size
    H-30in W-36in L-24in
    Chimney Size
    Firebox Air Inlet openings
    6in round and need 3 of them
    Fire box to cook chamber opening
    Half moon design H-6in L-16in
    Same opening for reverse flow plate at oppisite end of cooking chamber
    Height of reverse flow plate
    10in off bottom
    Cooking rack
    Working now on preping trailer so before we start on the tank just want to make sure im on the right track with all my calulations. Any adviced would be apperciated!
  2. I didn't run the numbers but it sounds like your on the right track. I also see this is your first post. So when you get a chance will you drop by roll call so everyone can give you a proper SMF welcome?

    Happy smoken.

  3. @themule69 did go on over to roll call to do a thread on there. With all of my calulations the only one im kinda confused on is my FF to CC opening. It said i needed 23in of opening, so would my 6x16 opening be enough or is that to big? And then with my reverse flow plate that means i need 23in of opening in that as well correct? Which would roughly put me at 8in from end with 14in across. This one stumps me a,bit,and is probably one of the most important to get spot on.
  4. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

  5. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    The dimensions of that particular tank, may not work for a reverse flow smoker..... It may be too long and skinny to work properly....
  6. inkjunkie

    inkjunkie Master of the Pit

    Even with my extremely limited knowledge of RF's that is what I was thinking. My little 60 gallon one I am planning is 23" or so in diameter, with a cc volume of 13860 cubic inches
  7. Thanks for the link share. DaveOmak. I did those calculations and its coming up with 2in segment height. Ive still very confused by it. Math never was my strong suite haha. Im confused on how it wont work as a reverse flow smoker. I know the diameter for that long of a smoker isnt ideal but as long as my openings to FB to CC, RF plate height and opening are correct with the correct stack size and height are right it should work correctly, right? Or is it cause with that being so long,and,skinny its not gonna carry the heat properly? Need help?!
  8. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    QUOTE: Dimensions 30in diameter by 10 feet long.

    30" x 120" length = 84,823 cubic inches.....

    FB/CC opening = 339 cu. in.
    Under RF plate = 339 cu. in.

    FB volume = 27,991 cu. in. 30 x 30 x 31

    FB air inlets = 85 sq. in. (80 below the fire grate, 5 or more above)

    exh stack 8" ID x 30-36 height... would work....

    RF plate height (ED) 14"

    RF plate width 30 "..

    The smoke channel below the RF plate takes up 1/2 of the smoker volume.....
  9. [ATTACHMENT=1992]IMG_3183.jpg (635k. jpg file)[/ATTACHMENT]
  10. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    I would cut the tank down to make a 6' and 4' smokers....
  11. That pit calculator is confusing. I did the tank chamber size so instead of 30x120 it was 320 gallons. with the rounded end i dont which is correct. for my RF plate could i drop the height of it if i had more of a opening at the end? The round end of the tank wont have my cooking grate over it so that leaves a good amount of room. Just want to see if i can make this a reverse flow or if im,going to,have to cut the dome off the one end. Which would bump it down to 96in
  12. If i cut the domes of the ends of my tank the new dimensions would be 30x88. Would that then work for a reverse flow?
  13. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    What is it you want, exactly.... The numbers I put in post 8 will work.... The smoker won't work that well.... too much surface area per volume.... too much heat loss...

    One member on here made a tank similar to yours into a "Jambo type smoker" and it worked great...
  14. Jambo type is just a straight stick burning correct? Firebox on one end and exhaust on other? No tuning,plate or anything like that? Thats how my last one was. Had a hot end and a cool end. Which i didnt like. Granted it was only 4 feet long so could fill it up very quickly and always had to rotate. With this tank my cooking area is almost 2x that so it wouldnt be to terrible. FF and FF to CC would be the same as the calculations you did correct?
  15. bruno994

    bruno994 Master of the Pit

    Yes, Jambo pits are direct flow, but the FB to CC opening is different than traditional offsets, it is angled upwards so that it actually enters the chamber above the bottom grate.  This also helps create as Jamie Geer likes to put it, his "Texas Microwave", which is the upper grate on the opposite end of the firebox.  Most comp cooks using Jambos will cook their chicken up there.
  16. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

  17. bruno994

    bruno994 Master of the Pit

    Actually coming in to the CC, there is an angled piece, shooting the heat and smoke basically above the lower grate...a couple examples..

  18. bruno994

    bruno994 Master of the Pit

    Here is an internal pic of a new line of pits and smokers being built by Champion Smokers...great looking rigs...

  19. [ATTACHMENT=1993]20150323_134445.jpg (2,749k. jpg file)[/ATTACHMENT]
  20. bruno994

    bruno994 Master of the Pit

    Would not recommend your FB to CC opening be that high up, all your heat will stay high, unless your exhaust was below the lower grate.  

    Thinking about a tank that size, you would probably benefit from building a center fired, reverse flow designed smoker... There have been several documented builds like that on here.  I can't remember who, but if all else fails, do a quick search in the tool bar above for center fired smokers. 
    Last edited: Mar 23, 2015

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