One thing I would really love to know is - at what point in the inlet duct does the dynamic flow change to static pressure. I would assume this would vary with different shaped ducts and different dynamic flow ( airflow speed). 

Your opinions on this or guesstimates ie 1", 2" or 3" from the face of the rad, would be of great interest to me.

George (down under

It doesn’t happen at a ‘point’.  The static pressure builds as the velocity is reduced.

Al