From:         David Lednicer <dave@amiwest.com>
Date:         21 Aug 94 15:35:10 
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	Great series of articles on commercial engines!  Just a few quick 
notes on Karl's comments.  

	To say the CF6 is a derivative of the TF-39 is a bit of a long reach.  
Look carefully at a TF-39 - for starters it is the only high bypass turbofan 
with a 1 1/2 row LP fan!  Yes, one row (the first) has blades that only go 
half way out, where they come to a fixed shroud that then has fixed stators 
going to the outer casing!  Other turbofans have core superchargers, but they 
are always behind the LP fan.  There are a lot of other differences between 
the two engines.

	The early CFM56 export problems were due to the ancestory of the 
core - it is the core of the F101, as found in the B-1 bomber!

	Lastly, the GE engine on the Convair 880 were straight turbojets, 
but I believe that the 990 had aft fan engines.  The GE aft fan engines 
were also flown on a Caravelle (I think called the Caravelle Horizon), but 
never entered service.  Additionally, the Caravelle entered service with 
RR Avons, but late production Caravelles had P&W JT8Ds.  This and the 
Mercure are little know JT8D customers.

David Lednicer             | "Applied Computational Fluid Dynamics"
Analytical Methods, Inc.   |   email:   dave@amiwest.com
2133 152nd Ave NE          |   tel:     (206) 643-9090
Redmond, WA  98052  USA    |   fax:     (206) 746-1299