Re: 757 engine (fan?) noise during freewheel

From:         barr@netcom.com (Keith Barr)
Organization: NETCOM On-line Communication Services (408 261-4700 guest)
Date:         28 Sep 95 03:52:45 
References:   1
Followups:    1
Next article
View raw article
  or MIME structure

In article <airliners.1995.1496@ohare.chicago.com>,
Henry Law <hjl@thelaws.demon.co.uk> wrote:
>I've heard it in these circumstances for years so it's obviously not
>what it sounds like (which is the fan blades hitting the cowling! :-)
>but I've always wondered what it was.  Can one of our 757 jockeys
>enlighten me?

I am not a 757 jockey (sniff), but the clinking is the fan blades moving
around in their mounts.  The mounts have a little bit of play in them to
allow for expansion due to heating when the engine is running.  Centrifugal
force holds the blades in the proper position when the engine is running.

You will hear similar sounds on most all turbofan engines when they are
slowly spinning.

--
Keith Barr        barr@netcom.com
      COM-ASMEL-IA-A&IGI
  Westminster, Colorado, USA
http://chinook.atd.ucar.edu/~barr