This has the makings of an interesting thread. I'd like to try & get an understanding of how the variables interact with one another.

Noticed a comment "The flow rate calculator in the link is for fluids, not air."earlier on in the discussion but isn't air classed as a fluid? I think all gasses are regarded a fluids. They are complex in some respects as they are compressible fluids as opposed to liquid fluids which are generally regarded as incompressible.

Looking forward to learning a bit about flow rates & fluid dynamics....