Re: GE90 Engines

From: (William Joseph Solomon)
Organization: University of Tasmania, Australia.
Date:         30 Jun 95 03:47:06 
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  or MIME structure (Lars A Ewell) writes:

>To Whom it May Concern,

>	I read in yesterday's New York Times that the
>delivery of GE90 engines to Boeing for use in 777s
>for British Airways could be delayed to due
>failure of the engine in the 'bird ingestion test'.
>In this test, an eight pound bird carcass is fired
>from a cannon into an aircraft engine running at
>full throttle. Evidently, the engine survived the
>test but had unacceptable levels of vibration after-

>	The article went on to say that GE was
>working on a redesign. I wonder what kind of design
>features an engine could be fitted with that would
>help to pass such a test? Presumably other engines
>have passed this same test. Is anyone familar with
>such features?
>	Lars Ewell

When a 'bird' is fired into an engine, the Fan (transonic
compressor) at the front will absorb the impact. Anything
which makes it past the fan will usually exit the engine
relatively harmlessly via the bypass duct.
So it is a matter of re-designing the fan so it can
survive the experience and still function adaquately.
Exactly how they are going to do that is an interesting

Does anyone know if they have had problems because they have
been trying to use fan blades made from composite materials?

Bill Solomon,
Civil&Mechanical Engineering Dept.
University of Tasmania, Australia