| 摘要 |
A fan assembly including a fan hub engaged with a driving means for rotation, a streamlined hub cover and a plurality of fan blades attached to the fan hub. The fan blades have an exterior fiberglass skin, filled with high-density polyurethane foam, and a reinforcing steel spar positioned within the exterior skin. The spar is fabricated in a tapered "H" cross section to provide maximum strength without impairing the efficiency of an optimum airfoil.
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