GE Started Testing The World’s Largest Jet Engine

How large is the world’s largest jet
engine? So large that Shaquille O’Neil
would fit inside it with Kobe Bryant
sitting on his shoulders. Engineers at
GE Aviation just assembled the first of
these engines and put it on a test stand
at the company’s massive boot camp
for jet engines located in the woods
near Peebles, Ohio.
It’s a giant.
The brand new GE9X is a winner in
several disciplines. Its front fan spans
a full 11 feet in diameter (3.35
meters), a world record. The engine
also has 3D printed fuel nozzles and
the most extensive use of parts made
from lightweight and ultra heat-
resistant materials called ceramic
matrix composites (CMCs).
Top and above: Meet the GE9X. When
Boeing decided to build the 777X jet,
the next-generation version of the 777
jet, it asked GE to develop an engine to
power it. Image credit: GE Aviation
Additive manufacturing , popularly
known as 3D printing, essentially
grows parts from the ground up and
allows engineers to design complex
internal shapes that were previously
impossible to achieve. “These tunnels
and caves are a closely guarded
secret,” says GE Aviation spokesman
Rick Kennedy. “They determine how
the fuel moves through the nozzle and
sprays inside the combustion
chamber.”
CMCs operate in temperatures as high
as 2,400 degrees Fahrenheit. The
material is inside the combustor and
the turbine. It allowed engineers to
keep the heat higher inside the engine
while reducing fuel burn and
emissions. “The hotter the engine
runs, the more efficient it is,” Kennedy
says.
The engine also includes 16 fourth-
generation carbon-fiber fan blades at
the front of the engine that feed air
into an 11-stage high-pressure
compressor with a 27:1 pressure ratio,
which also boosts the engine’s
efficiency. No other commercial
engine in service has a pressure ratio
that’s higher.
Although this is the first time the
company fired up the whole engine,
it’s been testing individual
components and systems for four
years. “Due to the significant amount
of new technologies in the GE9X, we
planned the testing program
differently,” says GE9X program
leader Chuck Jackson. “The early
testing informed the design and
manufacturing and allowed us to
freeze the product definition and test
the total engine as soon as possible.”
The GE9X was designed to generate
100,000 pounds of thrust. (One space
shuttle main engine produces 375,000
pounds.) While that may seem like a
lot, the world record belongs to the
engine’s predecessor, the GE90-115B,
which generated 127,500 pounds of
thrust.
When Boeing decided to build the
777X jet, the next-generation version
of the 777 jet, it asked GE to develop
an engine to power it. GE Aviation,
which is the exclusive engine maker
for the 777X, has received orders for
more than 700 GE9X engines valued at
$29 billion (list price) from airlines
including Emirates, Lufthansa, Etihad
Airways, Qatar Airways and Cathay
Pacific.
GE has been testing the new design for
the GE9X carbon fiber blades on a
scaled-down testing rig at Boeing.
Image credit: GE Aviation
GE Aviation invested $10 million to
prepare its Peebles Testing Operation
for the GE9X. Some of the money paid
for the largest “bellmouth inlet duct,”
the white funnel attached to the front
of the engine during testing. It
measures 18 feet in diameter and 12
feet in length.
Engineers also installed a fourth fuel
tank to keep the engine well fed,
fortified the bunker-like test stand to
secure the engine and added new
material to the testing stand air
systems to withstand the high
temperatures. “We also upgraded our
engine hoists and transporters to
handle the GE9X and modified a wall
in our prep building so the engine can
be moved after final assembly to make
its way to the test stand,” said Brian
DeBruin, plant manager for GE
Aviation’s Peebles Test Operation.
GE Aviation started testing the first
GE9X in March and will continue for
several months in order to verify
aerodynamic, thermal and mechanical
characteristics of the engine. The
company will start testing the second
GE9X next year. The engine is
scheduled to enter service by the end
of the decade.
By the way, GE also built the first U.S.
jet engine in 1942. You can watch that
story here .
The GE90 blade (above) made its way to
New York’s Museum of Modern Art.
Where the GE90 has 22 fan blades, the
GE9X will have just 16 blades made
from 4th-generation carbon fiber
composite. Image credit: GE Aviation