Standard Reverse Flow Smoker Calculator... by DaveOmak and others... Ready to use.. rev5.. 6/19/15.

[2angelsbbq]

Hi all....been going through a bunch of threads while designing a RF smoker.  I've been designing on CAD program and now have found I need to make a lot of changes.  Until now I didn't know about the RF factor in the calculator.  Glad I found it now while I am still in the designing stages.  I have everything adjusted for my 500 gal build.  Now that I have had to raise my RF plate and FB-CC opening by 5 inches, was wondering what is a good distance between the RF and the lowest cooking grate? I don't want to put it too low.  Right now with the calculator you guys have supplied i have my RF plate 2.5" below center of the tank.  I wanted to keep my lowest rack at center but I am afraid that is too close now....any advice?   Thanks

Rain

 

[daveomak]

Harley, morning... a 500 gallon tank is a tough one..... the opening under the RF plate doesn't fit the calculation too well.... You can lower the RF plate without creating any problems.... Another point to ponder is, moving the FB into the CC about 18 inches or so.... that effectively reduces the friction loss from the RF plate and allow for better air flow... then lowering the RF plate is not a problem.. The end gap on the RF plate can be reduced also...
Once all that is done, a "heat shield" is pretty much mandatory in the FB to reduce the heat to the cooking rack... the area above the FB will get pretty hot if you don't.....
All this calculating stuff is just a guide line and can be tweaked as long as maintaining a good air flow is still in consideration....

Dave

Heat Shield.jpg

• daveomak
• Dec 4, 2015

 

[2angelsbbq]

Dave

I was hoping to be able to put a rib box above the FB too.  If I move the FB 18" into the CC that would nix that idea.  As it stands I was cutting off one of the hemispherical ends to put the FB and RB.  According to the calcs I needed a 16" high RF opening.  I can do that no problem but I just wondered how high above the RF plate should i put my cooking rack.  I have seen numerous people on different threads have done this style of smoker.  I just dont have the dimensions of there cooker or how it worked after the build.

Thanks

Rain

 

[2angelsbbq]

Dave

As my original plan sat my RF plate was 13" off the bottom instead of the 16" your calculator called for.  Do you think I should leave it there?

Thanks

Rain

 

[gary s]

A 500 gal tank, big smoker   is the Dia about 41 in. ?

Gary

 

[daveomak]

14" is about all the lower I would go without inserting the FB into the CC... You can put the warming oven on the non FB end... and insert the FB... There are many combinations that will work....

 

[2angelsbbq]

Gary

The ID is 36.5 with approx 1/4" wall.  Cutting off one of the ends I have a length of 101.5 to the tip of the other end.

Rain

 

[2angelsbbq]

Dave

I'll split the difference and make it at 14.5.  If I put the lowest rack an inch above center that will give me a 5" space between the RF and the cooking rack.

Rain

 

[daveomak]

I see Gary stopped in to answer your questions..... I'll back out.....

 

[gary s]

Looking back at some of the builds and running calculations on smaller smokers the vertical measurement averages between 33 and 35 % of the dia.

I have never done a smoker that large, but thinking that 12 to 13 inches should be plenty That is a huge opening for plenty of heat and smoke.

I like Dave's idea of insetting the Fire Box.

Gary

 

[2angelsbbq]

The rib box I wanted to put over the FB was going to be a cooking chamber also.  I was going to put a damper in the top of the FB to add heat and smoke to that portion and I was going to install a water pan inside.  Does this all sound like I'm crazy?

 

[2angelsbbq]

I would appreciate any and all help

 

[2angelsbbq]

500 gallon RF smoker with rib box no grill-Model.j

• 2angelsbbq
• Dec 2, 2015

This is the original design I was working with.  I put the outer shells in transparent to see the insides

 

[gary s]

Some People Like water pans, and at times they can come in handy, make it removable and you are covered.

Looks like a heck of a smoker,  I guessing you are planning on cooking for lots of folks.

Gary

 

[2angelsbbq]

Gary

The water pan is removable.  I just put it in because I was afraid of getting too much heat from the firebox.  Im looking to start doing our neighborhood Memorial day and maybe 4th of July Shindigs...LOL

 

[gary s]

Sounds like fun, you will be the hit of the neighborhood,  Nothing like cooking for others.

We did a vertical RF a few years ago and did a water pan   

1_IMG-20121229-00063 (3).jpg

• gary s
• Dec 4, 2015

2_IMG-20121229-00061.jpg

• gary s
• Dec 4, 2015

IMG-20130107-00085.jpg

• gary s
• Dec 4, 2015

Gary

 

[2angelsbbq]

I remember going through that thread.  That was my original plan to do a big vertical RF after I read that.  But I got a tank on the cheap and couldnt pass it up

 

[gary s]

I can't wait to see that monster

Gary

 

[2angelsbbq]

I can't wait either. I think it will be amazing!

 

[inkjunkie]

Perhaps I missed it....how does one figure out the exhaust using square in place of round?