Blades were made in the 70's by Santa Rosa Machine in California. There a 3 blades.
Length 13' 8 1/8"
Chord 10 1/2", constant chord
10 Ply Sitka Spruce, bonded with resorcinol glue

Mounting flange on end of blade
Length 16"
Width 10 1/8 or 10 7/8, can't read friends writing
Thickness 2 1/2"