The General Electric GE9X is a
high-bypass turbofan developed by
GE Aerospace
General Electric Company, doing business as GE Aerospace, is an American aircraft engine supplier that is headquartered in Evendale, Ohio, outside Cincinnati. It is the legal successor to the original General Electric Company founded in 1892, w ...
exclusively for the
Boeing 777X
The Boeing 777X is the latest series of the Long-haul, long-range, Wide-body aircraft, wide-body, Twinjet, twin-engine jetliners in the Boeing 777 family from Boeing Commercial Airplanes. The changes for 777X include General Electric GE9X engi ...
. It first ran on the ground in April 2016 and first flew on March 13, 2018; it powered the 777-9's
maiden flight
The maiden flight, also known as first flight, of an aircraft is the first occasion on which it leaves the ground under its own power. The same term is also used for the first launch of rockets.
In the early days of aviation it could be dange ...
in early 2020. It received its
Federal Aviation Administration
The Federal Aviation Administration (FAA) is a Federal government of the United States, U.S. federal government agency within the United States Department of Transportation, U.S. Department of Transportation that regulates civil aviation in t ...
(FAA) type certificate on September 25, 2020. Derived from the
General Electric GE90 with a larger fan, advanced materials like
ceramic matrix composite
In materials science ceramic matrix composites (CMCs) are a subgroup of composite materials and a subgroup of ceramics. They consist of ceramic fibers embedded in a ceramic Matrix (composite), matrix. The fibers and the matrix both can consist o ...
s (CMCs), and higher bypass and compression ratios, it was designed to improve
fuel efficiency
Fuel efficiency (or fuel economy) is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical energy, chemical potential energy contained in a carrier (fuel) into kinetic energy or Mechanical work, w ...
by 10% compared to the GE90. It is rated at of thrust, which is 5,000 lbf (20 kN) less than the GE90 highest thrust variant, the GE90-115, rated at .
Development
In February 2012, GE announced studies on a more efficient derivative of the GE90, calling it the GE9X, to power both the -8 and -9 variants of the new
Boeing 777X
The Boeing 777X is the latest series of the Long-haul, long-range, Wide-body aircraft, wide-body, Twinjet, twin-engine jetliners in the Boeing 777 family from Boeing Commercial Airplanes. The changes for 777X include General Electric GE9X engi ...
. It was to feature the same fan diameter as the GE90-115B with thrust decreased by to a new rating of per engine.
[ The engine for the 777-8X was to be derated to .][
In 2013, the fan diameter was increased by to . In 2014, the fan diameter was increased another to , slightly increasing thrust from .
In 2016, the engine's list price was ]US$
The United States dollar (Currency symbol, symbol: Dollar sign, $; ISO 4217, currency code: USD) is the official currency of the United States and International use of the U.S. dollar, several other countries. The Coinage Act of 1792 introdu ...
M.[
The first engine was expected to be ground-tested in 2016, with flight testing to begin in 2017 and certification happening in 2018.][ Because of the delays, the first flight test occurred in March 2018,] with certification expected in late 2019.
Ground testing
The first engine to test (FETT) completed its first run in April 2016. This engine completed 375 cycles in 335 hours run-time, which validated the engine design in terms of aerodynamic
Aerodynamics () is the study of the motion of atmosphere of Earth, air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dynamics and its subfield of gas dynamics, and is an ...
performance, mechanical system
A machine is a physical system that uses power to apply forces and control movement to perform an action. The term is commonly applied to artificial devices, such as those employing engines or motors, but also to natural biological macromolec ...
behavior and secondary air system heat management.[
The GE9X conducted icing tests in Winter 2017.][ The FETT was used for ground cold ]weather
Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloud cover, cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmo ...
testing in natural icing conditions such as ground fog; minor design changes using additive manufacturing
3D printing, or additive manufacturing, is the construction of a three-dimensional object from a CAD model or a digital 3D model. It can be done in a variety of processes in which material is deposited, joined or solidified under computer ...
were made within one month. Icing certification and evaluation finished during the 2017–2018 winter at Winnipeg, Manitoba
Winnipeg () is the capital and largest city of the Provinces and territories of Canada, Canadian province of Manitoba. It is centred on the confluence of the Red River of the North, Red and Assiniboine River, Assiniboine rivers. , Winnipeg h ...
.[
Simulated high-altitude conditions were used to test the GE9X for ice crystal icing (core icing) which was an issue for the GEnx. This testing improved the understanding of core icing as well as the more familiar ]rime ice
Rime ice forms when supercooled water droplets freeze onto surfaces. In the atmosphere, there are three basic types of rime ice:
*Soft rime forms when supercooled water freezes under calm wind conditions. It is milky and crystalline, like sugar ...
. A design change required for the GEnx was the addition of bypass doors between the booster and high-pressure compressor which open into the airflow path to reduce the chance of ice crystals entering the core.[
Design changes between FETT and second engine to test (SETT) addressed improvements required to meet efficiency goals: the minimum area in the duct between the HP turbine outlet and the LP turbine inlet was altered to set the operating line of the compressor, turbine and fan. The tip clearance at the front of the HP compressor was modified as a result of early running experience. SETT testing started on May 16, 2017, at Peebles, Ohio, 13 months after FETT; it was the first engine built to the finalized production standard for certification.][ During the FAA 150 hr block test, the variable stator vane (VSV) lever arm failed and its redesign led to a 3–month delay.][ SETT was followed by four more test engines by May 2018.][
The certification program began in May 2017.] Eight additional engines were involved for certification, as well as one for ETOPS
The Extended-range Twin-engine Operations Performance Standards (ETOPS) () are safety standards set by the International Civil Aviation Organization (ICAO) for Twinjet, twin-engine commercial passenger aircraft operations. They are a safety measu ...
certification installed in the aircraft nacelle. A core engine was tested in the Evendale, Ohio
Evendale (pronounced ) is a village in Hamilton County, Ohio, United States, within the Cincinnati metropolitan area. The population was 2,669 at the 2020 census.
Geography
According to the United States Census Bureau, the village has a tota ...
, altitude test cell to check blade vibrations and engines 003, 004, and 007 were assembled in 2017, and the fourth engine was used for flight testing later in the year from Victorville, California. In 2018 ten compliance engines (including two spare engines) were needed for the four 777-9
The Boeing 777X is the latest series of the long-range, wide-body, twin-engine jetliners in the Boeing 777 family from Boeing Commercial Airplanes. The changes for 777X include General Electric GE9X engines, composite wings with folding ...
flight-test aircraft.[ Type certification was planned for the fourth quarter of 2018.][
On November 10, 2017, a GE9X engine reached a record thrust of in Peebles, a new ]Guinness World Record
''Guinness World Records'', known from its inception in 1955 until 1999 as ''The Guinness Book of Records'' and in previous United States editions as ''The Guinness Book of World Records'', is a British reference book published annually, listi ...
breaking the GE90-115B record set in 2002. The block test engine ran at its operational limits, at triple red-line conditions: maximum fan speed, maximum core speed, and maximum exhaust gas temperature. Icing tests started in Winnipeg at the end of 2017. The initial 777X flight-test engines were shipped in 2018 for an initial 777-9 flight in early 2019.[ A quarter of the certification testing was done by May 2018: icing, ]crosswind
A crosswind is any wind that has a perpendicular component to the line or direction of travel. This affects the aerodynamics of many forms of transport. Moving non- parallel to the wind direction creates a crosswind component on the object and t ...
/inlet distortion, inlet
An inlet is a typically long and narrow indentation of a shoreline such as a small arm, cove, bay, sound, fjord, lagoon or marsh, that leads to an enclosed larger body of water such as a lake, estuary, gulf or marginal sea.
Overview
In ...
distortion , fan and booster blade vibrations, turbine blade vibrations and thermal survey.[
]
Flight testing
As it was larger than the GE90, the GE9X could only be installed under the wing on the Boeing 747-400 with its larger main gear struts and bigger tires and not the previous 747-100 GE testbed. The engine was tilted 5° more than the GE CF6. Boeing built a specially designed pylon for the testbed. Suspended on a strut, the fourth engine of the program began flight testing at the end of 2017. The engine, with a fan diameter of , is installed in a diameter nacelle, with of ground clearance. The engine and nacelle weighed with its new pylon and wing strengthening, compared to for the CF6-80C2s and its pylon.
In February 2018, the GE9X's first flight was delayed by problems discovered in the high-pressure compressor (HPC) variable stator
The stator is the stationary part of a rotary system, found in electric generators, electric motors, sirens, mud motors, or biological rotors (such as bacterial flagella or ATP synthase). Energy flows through a stator to or from the rotat ...
vanes (VSV) lever arms. Also a routine A Check on the 747 testbed CF6 engines discovered fan-case corrosion and high pressure turbine airfoils on allowable limits. It first flew on March 13 with the previous design of the VSV lever arm. In early May, the first flight test phase of two was completed after 18 flights and 110 hours of run time; the GE9X high-altitude envelope was explored and its cruise performance evaluated. The second phase was scheduled to begin in the third quarter.
By October 2018, half of the certification was completed, and eight development engines were used, mostly in Peebles, Ohio: #1 was stored; a fan blade was deliberately separated from the fan hub of #2 at takeoff thrust for the blade-out test; #3 was used for crosswind
A crosswind is any wind that has a perpendicular component to the line or direction of travel. This affects the aerodynamics of many forms of transport. Moving non- parallel to the wind direction creates a crosswind component on the object and t ...
ground testing and cyclic and load testing of the thrust reverser
Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's thrust for it to act against the forward travel of the aircraft, providing deceleration. Thrust reverser systems are featured on many jet aircraft to ...
cascade assembly; #4 explored boundaries of the flight envelope such as low altitudes; #5 ran an endurance test with rotors deliberately unbalanced to make the engine shake at the vibration limits allowed in service, a requirement for ETOPS certification; #6 did ingestion tests later in 2018; after LP turbine over-temperature tests, #7 did a second icing test phase in Winnipeg, Manitoba
Winnipeg () is the capital and largest city of the Provinces and territories of Canada, Canadian province of Manitoba. It is centred on the confluence of the Red River of the North, Red and Assiniboine River, Assiniboine rivers. , Winnipeg h ...
; #8 did the triple redline FAA 150 h endurance test. Eight compliance engines, plus two spares, were required for 777-9 flight testing.
A second phase, of 18 flights, began on December 10 to evaluate the engine control software and hot-and-high
In aviation, hot and high is a condition of low air density due to high ambient temperature and high airport elevation. Air density decreases with increasing temperature and altitude. The lower air density reduces the power output from an aircra ...
performance and lasted until the first quarter of 2019 before FAA certification the same year. By then water ingestion, crosswind, blade-out, hailstone
Hail is a form of solid precipitation. It is distinct from ice pellets (American English "sleet"), though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets generally fal ...
, bird ingestion and block or endurance testing had been completed. Flight tests were based in Victorville, California, and ranged as far as Seattle
Seattle ( ) is the most populous city in the U.S. state of Washington and in the Pacific Northwest region of North America. With a population of 780,995 in 2024, it is the 18th-most populous city in the United States. The city is the cou ...
, Colorado Springs, Colorado
Colorado Springs is the most populous city in El Paso County, Colorado, United States, and its county seat. The city had a population of 478,961 at the 2020 United States census, 2020 census, a 15.02% increase since 2010 United States Census, 2 ...
, Fairbanks, Alaska
Fairbanks is a Municipal home rule, home rule city and the county seat, borough seat of the Fairbanks North Star Borough, Alaska, United States. Fairbanks is the largest city in the Interior Alaska, interior region of Alaska and the second la ...
, and Yuma, Arizona
Yuma is a city in and the county seat of Yuma County, Arizona, United States. The city's population was 95,548 at the 2020 census, up from the 2010 census population of 93,064.
Yuma is the principal city of the Yuma, Arizona, Metropolitan ...
.
By January 4, 2019, eight test flights and 55 hours of run time had been completed. At the end of January, the turbine case and rear frame strut were damaged during the blade out test and relevant components were redesigned. In early May, the flight test program was completed after 320 hours run time, during which high-altitude cruise fuel burn was established. Engines were modified to a final certifiable configuration standard before the maiden flight of the 777X, delayed beyond the previously expected June 26 by a stator problem at the front of the 11-stage high-pressure compressor
A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor.
Many compressors can be staged, that is, the gas is compressed several times in steps o ...
. Before certification, final tests included a full durability block test, replacing the usual "triple redline" test at maximum EGT and both rotor speeds, as modern high-bypass ratio engines cannot achieve all maximum conditions near sea level. The high-pressure compressor stator redesign delayed engine certification into autumn, which delayed the 777X first flight until January 2020.[
On January 25, 2020, the GE9X had its first flight on the 777X, flying for 3 hours and 52 minutes, before landing at Boeing Field.
On September 28, GE announced its FAA type certificate, as eight test engines completed 8,000 cycles and 5,000 hours of running.
ETOPS approval needed 3,000 ground-test cycles to be completed as a requirement for entry into service.]
In 2022, a different issue with the GE9X paused testing of the 777X.
Design
The GE9X increases fuel efficiency by 10% over the GE90. Its 61:1 overall pressure ratio
In aeronautical engineering, overall pressure ratio, or overall compression ratio, is the amount of times the pressure increases due to ram compression and the work done by the compressor stages.
The compressor pressure ratio is the ratio of the ...
should help provide a 5% lower thrust specific fuel consumption
Thrust-specific fuel consumption (TSFC) is the fuel efficiency of an engine design with respect to thrust output. TSFC may also be thought of as fuel consumption (grams/second) per unit of thrust (newtons, or N), hence ''thrust-specific''. This fig ...
(TSFC) than the XWB-97 with maintenance costs comparable to the GE90-115B. The initial thrust of will be followed by derated variants.[ GE invested more than $2 billion for its development. Its nacelle is wide.]
Most of the efficiency increase comes from the better propulsion efficiency of the higher-bypass-ratio fan.[ The ]bypass ratio
The bypass ratio (BPR) of a turbofan engine is the ratio between the mass flow rate of the bypass stream to the mass flow rate entering the core. A 10:1 bypass ratio, for example, means that 10 kg of air passes through the bypass duct for eve ...
is planned for 10:1. The fan is housed in diameter case.[ The GE9X has 16 blades, whereas the similarly sized GE90 has 22 and the smaller GEnx has 18. Having fewer fan blades reduces the engine weight, improves aerodynamic efficiency, and allows the low pressure (LP) fan and booster to spin faster to better match its speed with the LP turbine. The fan blades feature ]steel
Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...
leading edges and fiberglass
Fiberglass (American English) or fibreglass (English in the Commonwealth of Nations, Commonwealth English) is a common type of fibre-reinforced plastic, fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened i ...
trailing edges to better absorb bird strikes with more flexibility than carbon fiber. Fourth generation carbon fiber composite materials, comprising the bulk of the fan blades, make them lighter, thinner, stronger, and more efficient. The GE9X also uses a carbon fiber composite fan case, first developed for the GEnx, to further reduce weight.
The high pressure (HP) compressor is up to 2% more efficient.[ As the GE90 fan left little room to improve the bypass ratio, GE looked for additional efficiency by upping the overall pressure ratio from 40 to 60, focusing on boosting the high-pressure core's ratio from 19:1 to 27:1 by using 11 compressor stages instead of 9 or 10, and a third-generation, twin-annular pre-swirl (TAPS) combustor instead of the previous dual annular combustor. Able to endure hotter temperatures, ]ceramic matrix composite
In materials science ceramic matrix composites (CMCs) are a subgroup of composite materials and a subgroup of ceramics. They consist of ceramic fibers embedded in a ceramic Matrix (composite), matrix. The fibers and the matrix both can consist o ...
s (CMC) are used in two combustor liners, two nozzles, and the shroud up from the CFM International LEAP stage 2 turbine shroud
Shroud usually refers to an item, such as a cloth, that covers or protects some other object. The term is most often used in reference to ''burial sheets'', mound shroud, grave clothes, winding-cloths or winding-sheets, such as the Jewish '' ...
. CMCs are not used for the first-stage turbine blades, which have to endure high centrifugal forces and extreme heat. These are improvements planned for the next iteration of engine technology.
The first-stage HP turbine shroud
Shroud usually refers to an item, such as a cloth, that covers or protects some other object. The term is most often used in reference to ''burial sheets'', mound shroud, grave clothes, winding-cloths or winding-sheets, such as the Jewish '' ...
, the first- and second-stage HP turbine nozzle
A nozzle is a device designed to control the direction or characteristics of a fluid flow (specially to increase velocity) as it exits (or enters) an enclosed chamber or pipe (material), pipe.
A nozzle is often a pipe or tube of varying cross ...
s and the inner and outer combustor
A combustor is a component or area of a gas turbine, ramjet, or scramjet engine where combustion takes place. It is also known as a burner, burner can, combustion chamber or flame holder. In a gas turbine engine, the ''combustor'' or combustion ...
linings are made from CMC, only static components, operating hotter than nickel
Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ...
alloys with some cooling.[ CMCs have twice the strength at one-third the weight of metal and require 59% less cooling.] In total, the engine has 65 CMC components, the most of any commercial aircraft engine at the time of its introduction.
The compressor is designed with 3D aerodynamics
Aerodynamics () is the study of the motion of atmosphere of Earth, air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dynamics and its subfield of gas dynamics, and is an ...
and its first five stages are blisks, combined bladed-disk. The combustor is lean burn
Lean-burn refers to the burning of fuel with an excess of air in an internal combustion engine. In lean-burn engines the air–fuel ratio may be as lean as 65:1 (by mass). The air:fuel ratio needed to stoichiometry, stoichiometrically combust gas ...
ing for greater efficiency and 30% NOx margin to CAEP/8. The compressor and high pressure turbine are made from powdered metal. The low-pressure turbine airfoils made of titanium aluminide (TiAl) are stronger, lighter, and more durable than nickel
Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ...
-based parts. 3D printing
3D printing, or additive manufacturing, is the construction of a three-dimensional object from a CAD model or a digital 3D model. It can be done in a variety of processes in which material is deposited, joined or solidified under computer ...
is used to manufacture parts that would otherwise be impossible to make using traditional manufacturing processes.
In August 2024, a first production bound engine will be delivered, with a new combustor liner design.
Specifications
See also
References
Notes
External links
*
GE9X press
{{DEFAULTSORT:General Electric Ge9X
High-bypass turbofan engines
GE9X
2010s turbofan engines