I don't know if the photos represent the final plenum wall shape, but the
right angle on the inside of the curve is very inefficient, as far as
everything I've read.  it will create much turbulence and lower its
effectiveness.  I also don't see others using just a simple radius to turn
corners.  this, of course, based on my eyeball engineering degree, from the
school of hard knocks :-)
Kevin Lane  Portland, OR
e-mail-> n3773@comcast.net
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