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Old 30th Sep 2004, 17:55
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betaboy
 
Join Date: Sep 2004
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Bristow out to lunch?

I found Bristow's ACE book pretty good generally, but, unless I'm missing something, he seems completely incorrect on the answer to the question "What are the advantages of a wide chord fan blade" (p. 67).

He writes "The chord is the LENGTH of the fan's blade from its center mounting to its tip. It can be said, therefore, that as a basic principle, the wider the fan chord, the higher the blade tip speed, the greater is the generated airflow speed and mass, and the greater is the discharged air pressure, resulting in an increase engine thrust."

I am quite certain than the word chord refers the WIDTH of the fan blade from its leading edge to the trailing edge. Googling "wide chord fan blade RB211" leads to many hits which point to benefits such as: lighter weight than a conventional fan with more strength, less mechanical complexity, better ability to handle FOD and bird strikes, higher fan throughput and better aerodynamic efficiency, etc. So what is Bristow talking about?

Also, while we're on the subject, does any body know how anti-icing is accomplished for the fan blades? Is it not required because the blades just don't tend to accumulate ice?
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