Only the front inside corner of the airfoils need to have a "miter cut" since the back ends will never be down at the same time. The fronts will only be down together at auto rotation, and this will be a maximum of 30 degrees.

Mold for out side surface. 2 part.

Undersize airfoil cut in Styrofoam.

Passageway put in Styrofoam for air, under pressure.

Could this be heated oil? Under pressure?

Shaped rubber bag over Styrofoam

Release film

Breather ply

Bleeder ply

Composite fabric

Release film

Mold.

The Styrofoam is used to lay-up airfoil. It is destroyed when removed after the process. It could be a stronger material and removed and reused because of the taper