Re: 777 engine tow-in

Date:         05 Nov 99 00:04:11 
From:         David Lednicer <dave@amiwest.com>
Organization: Analytical Methods, Inc.
References:   1
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Sunil Gupta wrote:
>
> Does anyone know why the engines on the 777 toe-in?  I've never seen
> this on any other airliner.

	Actually, every airliner's engines are mounted with both toe and
pitch.  According to Boeing design practice, toe is set to minimize SFC.
Sometimes, toe is also set by the need to improve engine-out handling
qualities.

	As an example, the JT9Ds on a 747-100 have 2 degrees of toe-in and no
pitch, but the inlet centerline has -4 degrees of pitch.  The PW4000s on
a 777 have 2 degrees of toe-in.

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David Lednicer             | "Applied Computational Fluid Dynamics"
Analytical Methods, Inc.   |   email:   dave@amiwest.com
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