| 摘要 |
A fan blade has a three dimensional shape that resembles a leaf. The blade is made of balsa or other suitable wood with the grain of the wood running along its length. The obverse surface of the blade is contoured and has a central vein and lateral veins running from the central vein to opposite edges. The reverse side has one or more channels. Braces are set in the channels. The braces are also made of balsa or comparable wood and their grain runs transverse to the direction of the gain of the blade.
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