Need Help w/ figuring out RF Fuel Tank Smoker/Cooker build

[thunder835]

Hello,

I'm hoping some of the experienced builders can help me out here. I'm going to be building a RF smoker out of a 275 gallon fuel/oil tank (already drained and cleaned). The dimensions of the tank are 61w x 27d x 45h. I plan to add a warming/cooking box above the FB. What I need help with is all the important figures to make sure I have proper air flow, stack size, FB size etc. I have looked at the post where you can punch in all the numbers to get the calculations but I just don't understand it. Hoping someone would be able to help me figure out all the important stuff to guide me along.

Mark

 

[ahumadora]

Hi there,

Post some pics and a drawing of what you envision and the folks here can help you.

More info you give the better the reply will be.

Also what you want to spend or not and what tools you have access too.

 

[thunder835]

IMG_1243.JPG

• thunder835
• Jul 28, 2017

 

[thunder835]

This is my sketch and what I came up with using Feldons calculations. My buddy is helping me build this and he has a fully functional body/fabricating shop.

 

[pete mazz]

Throat seems way too small

 

[thunder835]

Throat seems way too small

And thus why I'm asking for help...

 

[SmokinAl]

Have you tried out this calculator?

http://www.smokingmeatforums.com/a/reverse-flow-smoker-how-to-calculate-build-tutorial

Al

 

[thunder835]

Have you tried out this calculator?

http://www.smokingmeatforums.com/a/reverse-flow-smoker-how-to-calculate-build-tutorial

Al

I'm actually work with it now. I didn't understand it all at first but I think I got it....I hope

 

[thunder835]

IMG_1245.JPG

• thunder835
• Jul 29, 2017

This is what I came up with using those formulas.

 

[thunder835]

When figuring the actual interior dimensions of the CC to figure out the actual cu in area, should you factor in the space that's only useable above the RF plate or do you use the entire interior of the tank w/o any of the obstacles (RF plate etc.)

 

[SmokinAl]

I'm not a builder, so I hesitate to answer any of your questions.

PM "DaveOmak", he is the guy who designed this calculator.

I'll PM him too & he should respond to your thread as soon as he gets on here.

Al

 

[thunder835]

I'm not a builder, so I hesitate to answer any of your questions.

PM "DaveOmak", he is the guy who designed this calculator.

I'll PM him too & he should respond to your thread as soon as he gets on here.

Al

Thanks Al!

 

[akorte4]

You should convert your gallons to cu in. Taking the dimensions x's .7854 is only for a true circle tank. Use that as your starting number. I'll leave everything after that to the experts as I'm getting ready to start my first build as well.

 

[daveomak]

835, afternoon...  You have done well with the tutorial...

I used the tank's round bottom end as the size of the FB/CC opening to see where it took us...  looks good to me..

835 2017-07-29.png

• daveomak
• Jul 29, 2017

...

5f7 2.jpg

• daveomak
• Jul 29, 2017

Below is a cooker Ribwizzard built...  He said he likes this one best.  I think the dutch door, and the "tuning plates"  and dual exhaust that are tweakable, make it very friendly to cook with...

Ribwizzard 4.jpg

• daveomak
• Jul 29, 2017

If you decide on your original design, I would go with at least 2 exhaust stacks, that sucked smoke from 2 different levels inside the CC... both on the same end, the warming box end... 

~12 sq. in. for the upper air inlet and ~50 sq. in. for the lower air inlet and you will be cookin' in no time..  

Smoker exh and int 3 Ahumadora.jpg

• daveomak
• Jul 29, 2017

Smoker Exh and Intakes 2.jpg

• daveomak
• Jul 29, 2017

This ODD shape calls for some, liberties when building it..  I'm here to answer any questions you may have....  Dave

 

[ahumadora]

Looks like Dave has you covered with those numbers.

If in doubt lean towards the bigger side of dimensions as it is more likely to work than too small.

 

[thunder835]

You should convert your gallons to cu in. Taking the dimensions x's .7854 is only for a true circle tank. Use that as your starting number. I'll leave everything after that to the experts as I'm getting ready to start my first build as well.

I used the Feldons website and selected the "Tank Cook Chamber" option when I originally calculated the cu in. Then I used the interior dimensions using the .7854 formula to get the result I did.  There is an option for a "Cylinder-Type" cook chamber which I would assume would be the circle tank that you mentioned.

 

[thunder835]

 
835, afternoon...  You have done well with the tutorial...

I used the tank's round bottom end as the size of the FB/CC opening to see where it took us...  looks good to me..

835 2017-07-29.png

• daveomak
• Jul 29, 2017

...

5f7 2.jpg

• daveomak
• Jul 29, 2017

Below is a cooker Ribwizzard built...  He said he likes this one best.  I think the dutch door, and the "tuning plates"  and dual exhaust that are tweakable, make it very friendly to cook with...

Ribwizzard 4.jpg

• daveomak
• Jul 29, 2017

If you decide on your original design, I would go with at least 2 exhaust stacks, that sucked smoke from 2 different levels inside the CC... both on the same end, the warming box end... 

~12 sq. in. for the upper air inlet and ~50 sq. in. for the lower air inlet and you will be cookin' in no time..  

Smoker exh and int 3 Ahumadora.jpg

• daveomak
• Jul 29, 2017

Smoker Exh and Intakes 2.jpg

• daveomak
• Jul 29, 2017

This ODD shape calls for some, liberties when building it..  I'm here to answer any questions you may have....  Dave

Dave,

Thanks for checking on the calculations. I have a few more questions:

When figuring the actual cu in of the CC, do you deduct the space that will be used up by the RF plate or are you taking using the entire interior to get the proper calculations?

I plan to have 3 racks inside the CC, as for the 2nd exhaust that you suggest, would you want to see that down to the lowest rack or positioned more towards the center rack? Also, with using dual exhausts, would the 8" pipe still be used or would you downgrade to a small pipe?

When mounting the RF plate, are we mounting that basically "in-line" or just above the FB/CC opening or another height all together?

As far as the intakes are concerned, I like the idea of using one in the FB door. Am I correct in assuming a 4" pinwheel vent above in-line with the FB/CC opening and an 8" pinwheel vent in the door would work for the suggested numbers you mentioned (12 and 50?)

I think I get the idea for the rest of the calculations but I am sure there will be more questions.

Thanks for your help!!

Mark

 

[akorte4]

I used the Feldons website and selected the "Tank Cook Chamber" option when I originally calculated the cu in. Then I used the interior dimensions using the .7854 formula to get the result I did.  There is an option for a "Cylinder-Type" cook chamber which I would assume would be the circle tank that you mentioned.

Gotcha, sorry I didn't realize you were using that to help. I was afraid you were just using straight up dimensions.

 

[daveomak]

 

Dave,

Thanks for checking on the calculations. I have a few more questions:

When figuring the actual cu in of the CC, do you deduct the space that will be used up by the RF plate or are you taking using the entire interior to get the proper calculations?

Entire CC....

I plan to have 3 racks inside the CC, as for the 2nd exhaust that you suggest, would you want to see that down to the lowest rack or positioned more towards the center rack? Also, with using dual exhausts, would the 8" pipe still be used or would you downgrade to a small pipe?

I would go between the middle/bottom rack... and just above the top rack....  For exhaust pipe, I would stick with 2 each 8" stacks...  6" would choke off the smoker..   Black rigid wood stove pipe would work well...  They don't have to be much more than 18" above the CC....  and whatever they penetrate...

When mounting the RF plate, are we mounting that basically "in-line" or just above the FB/CC opening or another height all together?

It can be attached directly to the top of the FB..  or above.. 

As far as the intakes are concerned, I like the idea of using one in the FB door. Am I correct in assuming a 4" pinwheel vent above in-line with the FB/CC opening and an 8" pinwheel vent in the door would work for the suggested numbers you mentioned (12 and 50?)

Openings on a pinwheel adjuster are < 1/2 the area of the diameter...   2 -  8" for the bottom and 2 - 4" for the top would work...

I think I get the idea for the rest of the calculations but I am sure there will be more questions.

Thanks for your help!!

Mark

Ask away...  we want you to have the best functioning smoke in your town....    Dave

 

[thunder835]

Question: Does the end of the RF plate need to be cut straight across or must you cut the half moon shape to match the FB/CC opening?