We need to generate a coefficient for our sensors when attached to out pitot tubes. To do that we need to have a precise source of airflow.
The current thought process is leaning towards pvc pipe with a piston in it. Move the piston down the pipe and your are displacing a known volume of air, which we can send through our sensor and calibrate it.
Problem is for a 4in pipe and using 5/16in threaded rod (18 tpi) , that rod would need to spin at 8k rpm to move fast enough to hit our upper target for flow. Move to a 6in pipe, and use 1/2in threaded rod (9 tpi) and that number is a lot more reasonable 2k rpm.
Working on it.