DAR stands for Disc Area Ratio. The DAR is the ratio of the total area of the blades to the area of a circle the same diameter. A DAR of 92 means that the total blade area is 92% of the area of the equivalent circle. Large blade areas are achieved with overlapping blades.
The above propeller has a DAR of 92%.
The total area of the circle is
PI x (Diameter/2)2 = 3.141 x 3002 = 0.283m2
The total blade area would be:
PI x (Diameter/2)2 x DAR= 3.141 x 3002 x 0.92 = 0.26m2.
This produces a DAR of 0.260/0.283 = 0.92