Chuck Dunlap wrote:

Paul, you are advocating the use of a water manometer to measure pressure differences to predict airflows, how would you do this. This would work fine if the air was static, but it seems the position (direction) of the ends of the tubing would make a big difference in the readings, like a pitot tube, if the airflow has much velocity. I used aquarium air stones to diffuse the moving air when  I tried measuring across the radiator in a RX-7 a while back, but I never was sure  of the results. I had to get the car up to 70 MPH to get 1/2" difference in levels. The fan was removed for this test.

What we used in the 60's was a small chunk of porous foam such as a sponge
on the end of the tube. A small closed end pipe with small holes drilled into it on 
three or more sides like the static port on a pito tube would also work.

Paul Lamar
 
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