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On the Record with
TOM BRISKEN, GENERAL MANAGER, GENX PRODUCT LINES, GE AIRCRAFT
ENGINES
Developing the new engine for Boeing's 7E7 Dreamliner is "a huge
investment of at least $1 billion," according to Tom Brisken, general
manager of the GEnx program at GE Aircraft Engines. And that's just
for development: most analysts believe that program support costs,
either in terms of cash, in-kind or other forms of payment, will
more than double the bill.
GE and Rolls-Royce were each selected in April by Boeing to develop
engines for the 7E7. One requirement is a 15% improvement in fuel
efficiency over GE's current CF6-80C2, an industry standard for
widebody aircraft.
 "The
7E7 is all about economy and efficiency," Brisken told Show News.
Boeing aims to market the 7E7 as 20% cheaper than current, equivalent
airliners in purchase price and cost of ownership. The engines are
crucial in this equation, as maintenance now accounts for 40% of
an airliner's running costs, of which one quarter goes to the engines
(according to Snecma, which hopes to become a partner on the GEnx).
The engine, according to Brisken, will be extremely simple and
rugged. The goal, in a departure for the industry, is to sell it
without the Total Care Package (often called power-by-the-hour)
maintenance contracts that now make up a significant portion of
the engine manufacturer's revenues.
"We will still offer total care, including FOD damage, for airlines
that want it, but our notional view is for customers to do their
own maintenance," he said. That's because the engines will demand
so little attention. And when they do, simplicity and modularity
will streamline the task. GE will just ship modules.
"For example, the whole fan module will be part of the nacelle.
They can take off the propulsor and leave the fan in place on the
aircraft," Brisken said.
So confident is GE of the ruggedness of the engine that it will
dedicate just one of its own shops to GEnx repair and overhaul (although
there will be a total of 18 independent shops worldwide with the
capability to handle it).
Offering FOD protection as part of a total care package speaks
to the ruggedness of the fan, Brisken said. It will be a 111-in
diameter version of the composite fan on the GE90, which has had
only two blades removed as unserviceable in eight years and 4-1/2
million hours of airline service.
—John Morris
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The GEnx engine, at 55,000 to 70,000 pounds of thrust, will
eventually replace GE's highly successful CF6 family. The
first full engine will go to test in 2006,with engine certification
scheduled for 2007.
"While the GEnx is a new engine it is based heavily on technologies
GE has invested in over several years, including the GE90
and the CFM56 Tech56 programs," said Tom Brisken, general
manager of the GEnx engine programs. "Our focus is to mature
those technologies through an aggressive schedule of validation
testing over the next year."
The GEnx bypass ratio of almost 9.5 to 1 is the highest for
any GE engine ever developed. Pressure ratio will be 42 to
1. These advances are the key to 40% of the improvement in
fuel efficiency, as well as noise reduction.
The engine features:
- Front Fan. The 111-in composite front fan and composite
fan case provide 400 pounds in weight reduction. Based on
the GE90 blade design, the GEnx front fan benefits from
almost 20 years of GE research and development into composite
fan blade technology. GE has the only composite fan blades
in airline service, and they have exhibited remarkable durability
on the GE90.
- Compressor. The 10-stage high-pressure compressor
is based on the GE90-94B and remains the highest pressure-ratio
compressor in the industry. Earlier this year, GE ran its
development engine core #7, which validated and exceeded
expectations in terms of compressor efficiency and operability.
Engine core #8 will run in 2005 to further validate the
GEnx compressor design.
- Combustor. The GEnx will incorporate a twin-annular,
premixing swirler (TAPS) lean-burning design that allows
for efficient fuel mixing before ignition, resulting in
significantly lower NOx levels and better hot section life.
TAPS technology was developed over several years through
the Tech56 program, with more than 4,000 test cycles run.
- Turbine. A two-stage high-pressure turbine section
(HPT), with fewer airfoils than the GE90, is followed by
a multi-stage, counter-rotating, low-pressure turbine section.
GE has been developing counter-rotating turbine systems
since the 1980s, but this represents the first entry into
an airline engine. The counter-rotating design will reduce
swirl losses from the HPT and result in improved fuel burn,
and fewer parts in both the HPT and LPT.
In addition to seven GEnx engines dedicated to the certification
program, GE will build two GEnx engines for long-term endurance
testing as part of a multi-year engine maturation program.
By aggressively accumulating engine cycles years ahead of
any GEnx engine in revenue service, GE aims to better understand
the engine's operating characteristics and align repair development
with the engine maintenance cycle life.
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