Flutter & Swept Wing Aircraft

From:         estock@gandalf.rutgers.edu (Richard G. Estock)
Date:         13 Apr 94 02:46:23 PDT
Organization: Rutgers Univ., New Brunswick, N.J.
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I would appreciate an e-mail reply to the following query:

I enjoyed reading and recommend to all Clive Irving's "Widebody: The
Triumph of the 747".  The author mentions the problem of flutter with
all of the swept wing aircraft that Boeing (and presumably all other
manufacturers as well) developed.

I am confused about what this problem actually is, and how it
manifests itself.

What, then, is flutter?  What is the cause?  What happens to an
aircraft that is experiencing flutter?  If an observer were in a
chase plane, what motion would the observer see with an aircraft
ahead that is undergoing flutter?  What corrects flutter?

As I understand it, on a 7X7 wing there is in succession an:
	inboard flap
	inboard spoiler
	tabs (2)
	outboard flap
	outboard spoiler

>From one source, flutter was described as an oscillation
at some critical speed of the aileron.  Why just the aileron?  Or in
this case are the flaps, spoilers, et al, collectively considered an

Is the problem of flutter more pronounced with swept wings than
straight wings?  Or is it more a function of speeds approaching Mach
1 regardless of wing geometry?

Please understand that I am not an aeronautical engineer or even a
pilot, but I am an engineer with a technical background interested in
the how and why things work.

In addition to any answers to the above, I would be most appreciative
of suitable references to wing design as well as on flying a 747.  
Not that I doubt anything, but I am curious as to why a 747 needs all 
these flaps, spoilers, etc., and how they are used in actual practice.

Richard Estock    (estock@gandalf.rutgers.edu)