Width ratio

Mean Width Ratio and Disc Area Ratio.

Formulae;

  • MWR = average blade width / diameter
  • DAR = ( Pi x (diameter squared)) / 4

Pi = 3.14 (3.1415926535897932384626433832795 for the more pedantic, but this is a useless level of accuracy).

Average blade width should measured directly or deduced from DAR and Diameter.

A “standard” DAR is taken as 33%, whereby 33% of the arae of a circle equal to propeller diameter is blade.