Still no answer on my insulation question, so I am going to go with 1.5" hard insulation sandwiched between two 1/4" steel plates. I am working on designing the CC first as that for me is the driving factor. I would appreciate it if one of the master builders on this site could check my math and assumptions.
Based on the trailer that I have, I have a working area of 76" x 36" for my platform to build the CC on. I will hang the FB off the rear edge of the trailer. I plan on using a rectangular design rather than a cylinder. Assuming that I want to have the CC at least 36" of exterior height, and I am losing 2" on sides and top, I come up with an overall volume of 72x34x34=83,232 Sq. Inches.
Using Dave Omak's calculator:
FB/CC Opening = 333 Sq. Inches = 9.8 inches tall by 34" wide
Area under RF plate = 333 Sq. Inches so RF plate has to be 9.8 inches off bottom
Area required at end of RF plate = same as above, but I read that it should be 1.5 larger so 14.7 inches from end wall (total RF plate = 57.3 inches
Minimum volume FB = 27,467 Cu. Inches = 36" outside width (35.5" inside) x 31" outside length (30.5" inside) x 26" outside height (25.5" inside) = 27,610 Cu. Inches
FB Air Inlets = 83.25 Sq. Inches
ESV = 1831 Cu. inches
Stack Length = (assuming dual 6" stacks equally spaced) = 1831 / 2x(.7854x5.875x5.875) = 2 stacks at 34" each
I just have the following questions:
1. My trailer only has 24" clearance from the bottom of CC box to ground. Can I raise the FB so the FB/CC aperture is below the top of the FB? Otherwise I will have to shorten my FB height and lengthen the FB to account for volume.
2. How much of a lip is standard for the RF plate when using it as a drip pan / water holder?
3. Are there any preferences as to where to place the RF pan drain? Middle or end near the smoke turn around?
4. If I do go with the insulation, do you think I could get away with using a 1/8" steel plate for the exterior?
Any assistance will be greatly appreciated.