Re: Jet Engine Containment/GE90

From: (H Andrew Chuang)
Organization: Concentric Internet Services
Date:         17 Sep 96 02:24:40 
References:   1 2 3 4
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In article <airliners.1996.1838@ohare.Chicago.COM> Scott M. Thomson ( wrote:
> I think the key issue with the composite blade vs. titanium blade
> discussion is the weight savings of the containment band around the fan
> case.  I believe this is based on the analysis that the composite blades
> don't fail at the root fitting, so not as much mass needs to be contained
> (unlike titanium fan blades)?  This is reported to have resulted in a
> several hundred pound weight savings for the GE90.

The GE90 is significantly larger and longer than its competitors.  Hence,
it is considerably heavier than the PW4084 and the Trent 800.  GE needs
every single pound it can save.  Even with the aforementioned weight
savings, two GE90 engines are nearly 7,000 lb heavier than two Trent 800
engines, as R-R claimed.

I have just read a report on the B777 fuel consumption based on
Boeing-audited data.  In spite of its larger size, the GE90-powered
B777s burn approximately 1% less fuel than the Trent 800-powered B777s.
However, GE has spent two to four times more than P&W or R-R in devloping
a powerplant for the B777.  Thus, the 1% fuel saving may not be too
"cost-effective."  Furthermore, will GE ever be able to recover the GE90
development cost?  Being No. 3 in the B777 market share, and not being
able to find another application, the GE90 is unlikely to be a profitable
program for GE.

In terms of market share, the fuel-efficient V2500 has not been able to
catch up with the reltively archaic CFM56.  Thus, it's not a big surprise
that the GE90 cannot get a bigger chunk of the B777 market.

Similarly, the same scenario can be applied to the A3XX.  Airbus may be
able to come up with a better design than the B747X.  However, will the
delta be large enough to attract enough customers?  Will Airbus be able
to recover the development cost?  The customer base for B747-sized
aircraft is very small.  (Currently, there are about 70 to 80 B747
operators, many of which operate used planes, only.  Roughly, the top
20 B747 operators owns more than two-thirds of the B747 in service.)
Hence, it's no big surprise that Boeing is hurrying to sign up as many
customers as possible before Airbus has the chance to launch the A3XX.
If Boeing can get commitments from British, Japan, United, Cathay and
Singapore (these five airlines alone own approximately 25-30% of the
B747 in service and probably 40% of the B747-400), I really can't see
how Airbus can have a viable A3XX program.  IMHO, British Airways is an
absolute must for Airbus.