Google Reader (1000+)

"Sometimes that’s a reduction in span, or a thinning or thickening of portions of the blade, or a change to the “pitch” (the twist profile of a prop blade). Then off it goes to the CNC. The propellers start as a laminated maple blank, then bias plies of fiberglass are laminated over the wood core. Up to 36 plies are used on the three bladed propellers. On the blade itself, the laminates of fiberglass build up to .080 inch thick from root to tip. The fiberglass is more than a protective shell, it is the structural member of the blade. In most cases now we also use Carbon Fiber for increased structural stiffness."

Source : Google Reader