REVERSE FLOW CALCULATING TUTORIAL ....

Discussion in 'Reverse Flow' started by daveomak, Feb 11, 2015.

  1. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    lino likes this.
  2. Thanks Dave. That should be a big help to a lot of people.

    Happy smoken.

    David
     
  3. Dave,

    I'm not being critical.  When I go to the forums index, there is no area called "Articles" from which one is to find "Instructionals".  Not an easy site to navigate and i would certainly like to peruse the instructionals.  I accept that you were born here and I'm a newbie, but I can't figure it out.  Perhaps a blinding flash of the obvious?

    Jerry
     
  4. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Above this thread is a bar listing areas of interest..... Articles is near the right..... click on Articles .... it then at the top of the "thread" lists

    Articles......Recipes......Instructionals.......Forum FAQ

    Click on Instructionals....
     
  5. Again, thanks Dave.

    Jerry
     
  6. bob1961

    bob1961 Smoking Fanatic

    does the tank with rounded ends make up the part where we need to use 1.5 times the FB size for the calc to work properly ??....I am planning to cut the round ends off and weld flat plate on, i hate the round ends on smokers, thanks....
     
  7. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member


    No... Rounded ends have nothing to do with the 1.5 calculations... volume is volume.....
     
  8. bob1961

    bob1961 Smoking Fanatic

    what is the reasoning behind the 1.5 bigger FB then the calc says, the area under the fire grates that don't equate to usable FB area ???....
     
  9. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    You have misread the tutorial.....



    Smoker Calculator reasoning
    The concept for the changes is below.... Alien and his associates, did an amazing job putting the original calculator together... 100% of my numbers are based on his original numbers... small changes were made for the improvements due to design changes in smokers.....
    The original measurements were taken from SFB smokers with tuning plates I do believe.... The advent of the RF smoker did not make any changes to the calculator... Now the exhaust has to travel twice as far as before, and the original FB/CC opening restricted the air flow from the FB, causing the FB to over heat... Some would get up to 450 deg and higher while the CC wouldn't get over 250.... And then there is the increased friction from the steel.... When using natural draft, any restriction/friction is very detrimental to the flow....
    So, on a whim, the FB/CC opening was enlarged, the area under the RF plate was increased and the area at the end of the RF plate was increased... all by 50%.... That solved ALL the problems.... fuel consumption was reduced.... folks were happy....
    I personally experienced members improvements and fuel usage by the letters/PMs they wrote me on their improvements...... One additional modification was suggested.... members here, tested a second air inlet to the FB.... directly across from the FB/CC opening... That was a significant improvement of some/most smokers.... If the FB was too hot, it could be cooled by opening the upper air inlet.... Also, the fire had a separate air inlet to adjust it's heat output.... It should be installed at or below the wood fire grate....
    All of this has been tested and proven by members building smoker on this forum.... The only place you will find using these numbers... or it used to be... I'm sure many builders are now using these ideas for their builds.... this process has been going for at least 2 years....

    Thanks for all your help...... DaveOmak
     
  10. bob1961

    bob1961 Smoking Fanatic

    thanks again dave, I just wasn't seeing why reading a lot of threads....so a non RF SFB smoker you can use the calc without going up 50% like you said....getting ready to start my 250 and trying to go with a RF or just a SFB smoker Thumbs Up ....
     
  11. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Using the larger openings will probably be a plus even if building a SFB with tuning plates... The loss in cooking room is maybe 3" in vertical height.... I would sacrifice that 3" to insure the smoker flowed air properly... once built, it's almost impossible to retrofit the smoker.... having to move the FB and RF plate.....

    Just my 2 cents...
     

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