allenb wrote:

In my impatience I broke out the abacus and slide rule and here's what I've come up with for Rob's neat asymmetrical round RC for a 1 lb fluidbed:

- RC diameter = 4"
- RC bottom is sloped at a 45 degree angle down to the point where it meets the perf plate which is flat.
- perf plate area is 25% of a 4" circle or 3.142 square inches.
- perf holes diameter = .125" or 3.175 mm
- holes center to center approximately .318" or 8 mm. (diamond pattern).
- perf open area % = around 14%
- total combined open area = around .4418 square inches.

For calculating perforated metal % open area (for 60 degree staggered center) you can use this formula: (hole diameter squared x 90.69) ? (hole center to center distance squared).

Allen