Analysis Pitch			How To
		Formula
			P (feet) = (101.33 x Va) / Na
				Va  = speed in knots through wake at zero thrust
				Na = shaft RPM at zero thrust
					zero thrust means knots and RPM at which thrust = zero
		Almost NEVER quoted by manufacturers as blade thickness, pattern and width all have
		a marked effect, so two props that appear identical but have different blade thicknesses
		actually have different pitch.
		Face pitch is measured 70% of the radius out from the axis of rotation.