[color=#000000]I've been doing some more thinking on my bench and have done a model of a pitot made from 50mm conduit bellmouths.
The size was chosen with a view to measuring from low volumes up to air speed in the tube of 20,000ft/min. Air speed was settled on in line with what John's FP1 pitot are rated for.
The idea was to have multiple pitot to cover the total of ranges I thought I might want.
I had access to CFD to do a simulation on the pitot model, (see attached pic) and found that the measuring pressure loss was a lot higher than expected, at 20,000ft/min, through the tube. For a volume of 261.94cfm a velocity dp of 22.89" H