Re: Engine noise question

Date:         01 Dec 96 04:08:51 
From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
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In article <airliners.1996.2589@ohare.Chicago.COM>, faurecm@halcyon.com (C. Marin Faure) wrote:>The "snarl" or "buzz" you hear from a large plane like a 747, 777,
>MD-11, etc. as they take off is really the fan noise, not the jet
>core noise, which is the roar part.

With regard to the DC-10, at least, I've heard that the distinctive
buzz is due to miniture sonic booms the tips of the fan blades go
supersonic.

When I flew on a United A320, I noticed this same buzz, louder than
inside a DC-10 and quite annoying.  Since United's A320s have IAE
V2500 engines, and CFM56s on both 737s and DC-8s don't exhibit this
same buzz, I'm assuming this is a function of the V2500's design.

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