Re: Geared turbofans

Date:         24 Mar 98 11:38:36 
From: (H Andrew Chuang)
Organization: Concentric Internet Services
References:   1 2
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In article <airliners.1998.468@ohare.Chicago.COM>, Steve Lacker  <no@spam.thanks> wrote:
>Pratt is hoping to run the fan at its optimum speed while simultaneously
>running the LP compressor at *its* optimum speed, withouth having to use
>a 3-shaft arrangement with its associated inefficiencies. The drawback
>to geared fans has always been the gearbox, but Pratt is saying they can
>use all the gearbox expertise they gained with their UDF (unducted fan)
>program to get a reliable, small, efficient gearbox.

UDF is GE's unducted fan which is not a geared-driven design.  You're
referring to P&W's ADP (Advance Ducted Propulsor).

>Nope. They're aiming at a midsize engine. In fact, they're aiming RIGHT
>at the CFM-56 family, hoping to cut into its market dominance. <opinion
>mode on> They should have done this YEARS ago- Pratt was once THE
>dominant maker in that market with the JT8D, and it still stands to this
>day as one of the best aero engines of all time, bar none. But after the
>JT8D 200 series, Pratt let that market segment go except through their
>rather unsuccessful collaboration on the IAE V2500. I just hope they
>haven't waited too long- CFM has a TIGHT hold on that market. </opinion

It can all sum up in one word -- complacency.  P&W cannot afford to be
complacent anymore.  Otherwise, P&W's commercial operation might soon
follow Douglas's footstep.  In the past few years, R-R seems to be
following the Airbus model -- compete in all market segments at any
cost.  Hopefully, with a major thrust in developing new products for
the next century, P&W will not have to take the Douglas's path.