I will just throw this out there because I have a Machinist background. Pitch is also used to measure threads. It is the linear distance from the peak of one thread to the next. Or the distance the thread travels in 1 revolution-same thing. Since the fan moves the same as a bolt would, rotary-wise, the distance the air would travel on the fan in one revolution would be the distance from the leading edge to the trailing edge. Maybe this is why the tech said what he did? Of course with fluid dynamics and greater speed the fluid (air) would increase its speed and linear distance traveled. But static distance in one revolution would give a common comparison measurement.
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