Calculating Method for rotary blade loss of axial fan is given. Calculations on the lossing and routine lossing models are carried out by the use of 20 groups of fan test data.

This is the same 'razor/razor blade' business model successfully employed in the videogame console business, where the hardware is sold at a loss and profits are made on sales of content.

Then the Outside Diameter of the blade is again measured very exactly, to determine Diameter Loss.