The unfolding and calculation method of spiral blades!

Forming diameter D. Axis diameter d, lead P, circumference L1 (outer circle), circumference L2 (inner circle).

Leaf width H=(D-D)/2.

L1={(D π) square+P square)} square again.

L2=((d π) square+P square) square again.

The inner diameter of an open circular ring (annular sector) is √ [(diameter of the shaft x π) x (diameter of the shaft x π)+helix distance x helix distance].

Open circular ring (annular sector) outer diameter=open circular ring inner diameter+(formed diameter - shaft diameter).

The outer arc length of an open circular ring (annular sector) is √ [(formed diameter x π) x (formed diameter x π)+helix distance x helix distance].