Mechanical Engineering
#2243
THE GEnx: NEXT GENERATION AVIATION
Chris Bellini (cmb167@pitt.edu), Jason Carney (jpc70@pitt.edu)
Abstract— Jet engines have been a modern convenience for
decades, yet General Electric has recently revolutionized
this common technology with the release of their next
generation jet engine, the GEnx. The GEnx has improved
upon other older jet engines designs with the addition of
modern composite materials, next generation compressor
systems, a revolutionary high-bypass system that decreases
noise pollution, and an advanced combustion chamber that
improves stability and drastically reduces standard
operation temperatures, among other improvements. This
paper will describe, in parts, how GE has improved upon the
design of their previous engine models with regards to
maintenance costs and the efficiency of the operation and
fuel systems. The first section will discuss how the use of
modern materials and composite parts makes the fan blades
and outer shell incredibly durable, while reducing the
overall weight of the unit and the cost of its maintenance.
The second section will describe the technical aspects of the
engine and how the improved temperature stability, counterrotation, digital diagnostics, and air-bypass systems
contribute to the overall longevity, performance, and
environmental benefits of the engine. In the third section, we
will discuss the ethics and impact of the GEnx and next
generation aircraft. GE has always been a leader in the
development of jet engines and mechanical technology, and
the new GEnx engine affirms that position by introducing
groundbreaking advancements into the field of modern
aviation science.
Thanks to the innovative use of carbon fiber blades with
titanium edges, each of the fan blades on the GEnx is larger
and more aerodynamic, allowing the GEnx to use fewer
blades than older engines [1]. Thanks to some 3D design
work by General Electric, the GEnx jet engine utilizes only
18 carbon fiber blades, in comparison to 22 on its
predecessor the GE90. Each of the new carbon fiber blades
is larger and moves more air than the smaller titanium blades
in its predecessor. In addition, the reduction in the number of
blades used on the fan of the GEnx reduces the resistance
caused by the friction of air moving over the surface of each
blade as it enters the turbine, which increasing performance
and decreasing overall weight [2].
Key Words—GEnx, carbon fiber, titanium, composite,
compressor, combustor, turbine
FIGURE 1
A CLOSE UP VIEW OF THE NEW TITANIUM-TIPPED CARBON FIBER
BLADES OF THE GENX [3]
MECHANICS OF THE MODERN JET ENGINE
Jet engines are vital to the everyday travel of millions of
people worldwide. The average person, however, never sees
the extremely complicated physics and mechanics behind the
operation of a jet engine. The modern jet engine is composed
of several main subsystems: the main fan and housing, the
compressor, the combustor, the turbine, and the maintenance
system. All of these systems must work together in order to
perform the engine’s main function, which is providing the
massive amount of thrust required to lift a standard
commercial airliner. Modern companies such as General
Electric are re-inventing standard jet engines by
incorporating new technologies to improve efficiency,
performance, and reliability.
In addition to the reduction in the number of blades,
General Electric has made the fan assembly removable from
the remainder of the engine, allowing a spare turbine to be
mounted without removing the entire assembly from the
wing of the aircraft. Using this method, GE has decreased
maintenance costs and downtime for all aircraft powered by
its GEnx engines. In the GEnx, General Electric began to
use a new high-bypass design; this involves allowing a great
portion of the air coming through the fan to leave the engine,
only using a small portion of the incoming air while the
remaining air bypasses the rest of the engine and leaves
through the honeycomb structure beyond the fan blades. Use
of the high-bypass design greatly reduces noise, improves
airflow and air quality through the compressor, and finally
increases fuel efficiency. This high-bypass setup allows
flying objects to be centrifuged to the outside of the fan duct
The Main Fan
University of Pittsburgh
Swanson School of Engineering
March 1, 2012
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Jason Carney
and discarded out of the engine through bleed ducts instead
of entering the compressor, resulting in costly repairs [2].
FIGURE 3
A CUT AWAY SHOWING THE BLISKS WITHIN THE COMPRESSOR OF THE
NEW GENX JET ENGINE [4]
FIGURE 2
A CUT AWAY SIDE VIEW OF THE GENX JET ENGINE ILLUSTRATING AIR
FLOWING THROUGH THE ENGINE [1]
The GEnx also utilizes a new high-pressure turbine that
was increased from nine stages to ten, creating the final 23:1
compression ratio within the engine. General Electric also
designed the two compressor sections to spin in opposite
directions. The low-pressure compressor spins counterclockwise while the high-pressure turbine spins clockwise.
The counter rotation of these two turbines actually improves
fuel efficiency by improving the transition between the two
stages.
The new design increases airflow, and has the highest
bypass ratio of any commercial engine available today at
19:2. This number means that the volume of air bypass the
compressor and combustor of the engine compared to the
volume of air entering the engine is in a 19:2 ratio. This
process decreases noise produced by the aircraft while
improving the quality of air flowing into the compressor,
increasing fuel efficiency. This innovation will help to
decrease noise pollution in areas surrounding commercial
airports, while also decreasing fuel costs [1].
In each of these stages, “blisks” or blade-disks are used to
increase the pressure of the outside air to the pressures
needed for efficient combustion. Instead of using standard
blades attached to a central disk, a blisk is one solid piece of
material that is both the blade and the disk, removing the
dovetail joints where blades are normally attached to the
disk [5]. Removing this joint improves overall strength and
reliability of the blisk, which increases the longevity of the
engine itself. These blisks spin at very high rates, and at
these rates, cavitation becomes a severe concern. Cavitation
occurs when a fluid is subjected to differences in pressure,
causing small vacuum bubbles of low pressure to form,
which then implode when entering areas of high pressure. In
a jet turbine, the fluid is air, and the areas of low and high
pressure are created from the spinning of the fan blades and
blisks. Inside the compressor, these small implosions of
bubbles can wear down the surface of the blisk, causing
cracks and failure.
The Compressor
The compressor of a jet engine is the section where the air
from the main fan is compressed before it is mixed with fuel
and ignited. The GEnx has one of the highest compression
ratios of any commercial jet engines, coming in at 23:1. This
means that the pressure of air leaving the compressor is 23
times that of the air that enters [2]. Compressing the air that
enters the jet engine allows the jet engine to optimize the
burn of fuel to maximize power output. To achieve this high
level of compression, General Electric uses a seven stage
low pressure compressor which differs from the older six
stage compressor. The stages of a compressor are disks with
varying number of blades that increase the pressure of the air
as it passes through each individual disk on its path through
the engine. In the GEnx, General Electric added the
additional stage, while reducing the number of blades for
each individual stage. The use of fewer blades with an
additional stage kept the weight the same, but increased fuel
efficiency.
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Jason Carney
increase exponentially at higher temperatures. The lower
combustion temperature, which “reduces exit temperature
variation by 205C” also reduces the strain on the
components after the combustor in the GEnx jet engine,
which decreases maintenance costs [1]. In other jet engines,
high temperatures after the combustor can wreak havoc on
the blades of the turbine. In the GEnx, the lower combustion
temperatures reduce the strain due to heat, saving these vital
components.
FIGURE 4
ONE OF THE TITANIUM-REINFORCED BLISKS (BLADED-DISKS) OUT OF
THE GENX [2]
.
Due to the use of a blisk instead of separate blades and
disks, cavitation is lessened due to the removal of the weaker
joint between the two pieces, but can still cause failure of a
blisk, shooting debris through the rest of the engine. If one
of these blisks fails, the rest of the engine is put in danger of
being shredded by metallic debris. To combat this problem,
General Electric uses very strong metal blisks, covered in a
special coating designed for use in very high temperatures,
paired with a state of the art tracking system that can predict
when a part will fail [1]. This system records the serial
number of every part within the engine, and tracks usage to
determine when one specific part could become damaged to
prevent a total loss. Instead of replacing a part after it fails
and destroys the parts around it, GE replaces the part before
it fails, saving other costly components downwind.
FIGURE 5
A CUT AWAY SHOWING THE TAPS COMBUSTION SYSTEM IN THE
COMBUSTOR OF THE GENX [7]
Maintenance System
Along with all of the innovative technologies used in the
mechanics and materials of the GEnx, there is also a state of
the art monitoring system that tracks every part in each jet
engine by serial number. This system warns technicians to
replace parts within the engine before they actually fail. The
system tracks the usage of individual parts by their usage,
and monitors the strains placed on the entire system to
calculate when a part could crack or warp. As mentioned
earlier, this system allows airlines to do preventative
maintenance on their engines, saving time and money.
The system includes multiple sensors throughout each
subsystem of the engine that track real-time data and
compare it against a General Electric model of the ideal
operation of the engine. This model took years to develop
and consists of thousands of hours of operational data of the
ideal operation of the jet engine [1]. This real-time
comparison allows the maintenance crew to look at each
engine’s usage and history and analyze anomalies. If any
issues arise, the crew can look into each subsystem at that
particular time to isolate which part caused the issue. The
computer system saves approximately $7 per hour of flight
time due to the more efficient use of both parts and labor [1].
The lowering of costs and increase in performance and
sustainability of the engine helps companies to maintain
lower operating costs and more reasonable prices for
everyone using their service.
The TAPS Combustor System
In the internals of the GEnx, after the compressor, the air
enters the specially designed combustion chamber of the
engine called a TAPS combustor.. The use of a Twin
Annular, Pre-mixing Swirler combustor in the GEnx has
greatly improved its fuel efficiency and reduced its
emissions. This technology uses a system of pre-mixing the
fuel and air before combustion to improve efficiency. In the
GEnx, air leaves the compressor stages, and is directed into
two high-energy “swirlers” near the fuel nozzles. These
swirlers create a vortex where air and fuel are mixed before
entering into the combustion chamber to be ignited. The
swirl of the air allows the fuel and air to mix more
completely, which creates a leaner mixture that burns at a
much lower temperature than the mixtures used in its
predecessors [6]. The lower temperature within the engine
reduces pollution because certain types of air pollution
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Titanium alloys, especially commercially pure (CP)
types, exhibit strong thermal stability (resistance to
decomposition at high temperatures) up to temperatures of
roughly 538-595°C (1000-1100°F), and it is possible for
certain titanium-aluminum samples to resist even higher
temperatures. This is important in jet engine design because
the components of the engine that are exposed to these
extreme temperatures must be made of materials that can
withstand such heat without fail. Also, titanium is known for
its exceptional corrosion resistance; it is far more resistant to
atmospheric corrosion and degradation than stainless steel
alloys. This is because titanium is naturally reactive with and
has a strong affinity for oxygen, so a thin yet incredibly
protective and durable film of oxide molecules naturally
forms on titanium surfaces when they are exposed to air and
moisture. This protective film continually forms and reforms
itself so long as the metal remains exposed to moisture and
open air. Thus, titanium and titanium alloys are very
resistant to open-air corrosion and oxidation (degradation
and chemical changes, such as rusting, due to a loss of
electrons) at high temperatures (up to 650°C/1200°F). This
is incredibly important in aeronautics because jet engine
components must be able to resist the negative effects of air
being combusted at very high temperatures and the unstable
chemical reactions that occur therein.
MATERIALS IN THE MODERN JET ENGINE
The materials used in the construction of a jet engine and its
component parts are equally as important as the mechanics
themselves; without the proper materials, the engine parts
simply will not function as efficiently as possible, if at all.
As such, important considerations must be made when
considering the materials of a jet engine. The components
must be thermally stable, corrosion-resistant, durable, easily
produced, and easily obtained, among many other concerns.
In order to meets these needs, the next-generation engines
are being built with some of the finest, most reliable
materials available. These materials will make the newlydeveloped engine components more durable than ever, while
greatly improving operation performance and reducing
maintenance costs. Modern companies, such as General
Electric, are utilizing high-strength titanium alloys and
durable carbon fibers in their new engines in order to
increase their performance and make them more durable and
reliable.
Titanium Alloys
Titanium has been recently used in jet engine construction
because of its strength, durability, and other properties that
make it useful in aviation technology. Other materials, such
as aluminum, stainless steel, and aluminum-and-nickelbased alloys are lacking in many of the benefits inherent to
titanium, making it a material of substantial use in modern
aviation science. For example, titanium is about 40% less
dense than other alloys and steels, which leads to an increase
in titanium’s strength-to-weight ratio [8]. This term simply
means that a small quantity of titanium alloy has the
equivalent strength of a larger quantity of an alloy of steel or
aluminum and nickel. This is crucial to aviation design,
because it means that less material can be used in
development of engine components. Thus, the resulting parts
will be lighter in weight yet just as efficient as similar parts
made with other alloys. Titanium alloys can be far stronger
than iron- and cobalt-based superalloys (alloys that exhibit
incredible strength, thermal stability, and corrosion
resistance) and certain iron-based steels as well.
In addition, titanium is very easily forged and casted into
many forms for mechanical and industrial use. It can be
made using standard, non-special industrial techniques and
fused together in a variety of ways. CP titanium and its
alloys are the most easily welded, allowing them to be
formed into component engine parts with little difficulty and
less cost than more non-malleable materials. While it should
be noted, however, that titanium can cost up to as four times
as much as some steels, such a price is also that of some
superalloys, which, with respect to jet engine components,
are not as stable and effective as titanium.
Titanium in the GEnx
The benefits of using titanium in jet engine design have not
been lost on General Electric, as they have incorporated
titanium alloys into many of the components of their new
GEnx engine model. Older models utilized other, more
inferior metals and alloys; General Electric has replaced
these older materials with stronger titanium alloys in some
cases and introduced titanium to the engine design in new
ways.
The fan blades of a jet engine are crucial to the system’s
proper operation. However, they are very prone to damage
from flying debris. The GEnx’s new fan blades have
titanium-tipped edges, giving them numerous advantages in
structural stability and performance. The blades themselves
are made with composite materials, but these materials can
be easily frayed by the force of the air passing over them. In
order to prevent the tips from fraying and compromising the
safety of the engine, they have been covered in titanium, the
durability of which will prevent the blade tips from needing
frequent maintenance. Also, these titanium-reinforced blade
tips redirect the force of debris collisions to the main body of
the blades themselves. In other words, the shock damage
caused by debris hitting a blade tip will not overly damage
it; the energy is transferred downward into the far stronger,
more durable composite material of the blade’s main body
[9].
Titanium alloys are also used in the latter-stage turbine
blisks of the engines’ compressor. Given that these turbines
are subject to rotation at high speeds and temperatures and a
Heat and Corrosion Resistance
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high volume of air flow, the blisks must be made of a highly
heat- and corrosion-resistant material. Titanium, as
previously mentioned, is very resistant to damage from heat
and oxidation, allowing it to perform tasks that require
resistance to extreme conditions.
CARBON FIBER & PLASTIC COMPOSITES
The use of carbon fibers in industrial design and
manufacturing has been a rising trend in recent years; the
numerous advantages that carbon fibers have over traditional
materials make them a very viable option for the structure of
many industrial products. As a design material, carbon fiber
filaments are more durable, less dense, electrically and
thermally stable, and easily formed into the shapes and sizes
necessary for product development.
Composition and Structural Benefits
FIGURE 6
THE MOLECULAR STRUCTURE OF GRAPHITE, IN WHICH MULTIPLE
A carbon fiber is a fiber filament that is composed of at
least 92 percent carbon [10]; the carbon is in the form of
long filaments which are woven together and sealed with a
resin that, when dried, provides incredible strength. These
fibers can be either very short or very long and continuous,
and their molecular structures lend them their superb
chemical and physical properties. Since carbon is a very
light element, they are very thin and lightweight, with fibers
measuring roughly 5-6 micrometers (1 micrometer = 10-6
meters) in diameter. As a result, carbon fiber filaments are
far less dense than other materials, causing them to
contribute much less weight to any engine components that
they are a part of. Also, they are a very elastic material; a
high elasticity means that they are able to very effectively
resist damage and retain their shape when stress is applied.
As a result, they can be easily constructed into various jet
engine components without the negative side-effects of
stress damage. This allows for more experimental
component design and a greater degree of reliability and
structural stability for parts made of carbon fiber.
The structure of a crystalline carbon fiber is most closely
related to that of graphite; multiple layers of carbon atoms,
bonded together in a flat, honeycomb-style arrangement.
These layers, due to the weak intermolecular forces that hold
them together, easily slide across each other horizontally.
LAYERS OF BONDED CARBON ATOMS ARE BONDED TOGETHER
VERTICALLY (AS SHOWN IN THE INSET) [11]
However, carbon fibers, when looked at on a longer scale,
are not made entirely of parallel layers of carbon, but rather
longer ribbons. While the surface layers are technically
parallel, the inner layers are warped into hairpin folds. These
folds prevent the ribbon layers from sliding past each other
as they do in graphite, granting the fiber strength, durability,
and elasticity parallel to the horizontal plane [11]. Also, the
more aligned the layers are, the stronger the structure
becomes; this type of arrangement is known as a fiber
texture. The stronger the fiber texture is, the greater the
carbon fiber’s properties, such as density, elasticity, and
tensile strength (the amount of stress due to stretching that a
material can handle before it begins to deform). Hence, a
carbon fiber that possesses these qualities would have
tremendous strength, elasticity, and durability when
compared to other, more conventional industrial materials
such as metal alloys.
Electrical and Thermal Conductivity
In addition to strong physical properties, carbon fibers are
also very stable in terms of electrical and thermal energy.
With the increasing strength of the fiber texture, a carbon
fiber becomes more electrically and thermally conductive.
The more conductive a material is, the more energy it can
stand to safely transfer. For example, a thermally-conductive
material may be used in the application of a heat sink, which
is a device that absorbs heat in a system (such as a computer
or an engine) and transfers it to the surrounding air, thereby
cooling off the system and keeping it from overheating.
Thus, fibers used in engine design that are structured this
way are able to prevent electrical- and heat-based damage in
the areas of the engine that they are incorporated into.
With regards to the aforementioned molecular layer
structure of the fibers, the bonds that hold the carbon atoms
of each layer together are caused by delocalization of certain
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electron orbitals (areas of negative charge around an atom).
When an electron is delocalized, it is no longer associated
with a single atom, but instead roams freely around the space
of the structure. This results in increased electrical and
thermal conductivity along the horizontal plane since the
material is more receptive to energy and electrical charges.
CARBON FIBER IN THE GENX
General Electric’s GEnx engine utilizes the best properties
of carbon fiber material technology in its redesign of
traditional jet engine components. Numerous parts of the
engine have been constructed using carbon fiber materials in
place of previously-used metal alloys, all with outstanding
benefits and results. By replacing aluminum and titanium
alloys with carbon fibers and fiber-reinforced plastics, GE
has greatly enhanced the performance of its newest jet
engine.
FIGURE 7
THE CARBON FIBER FAN BLADES OF THE GENX, WITH TITANIUM-COATED
EDGES [12]
Fan Blades
Composite fan blades are stronger and lighter than
traditional titanium blades, and General Electric has also
designed the engine to work with less blades—and thus less
weight—than previous models; the count has been reduced
from 22 to 18. This change increases efficiency and
decreases noise by reducing the amount of “scrubbing” on
the blades; a phenomenon that involves the drag force of air
and air resistance wearing down the blades as air moves
across their surfaces. When the blades were tested on the
earlier GE90 model, they were given a 30-year lifespan, and
“after a decade of performance and 6.5 million flight
hours…only three composite blades [had been] removed
from service” due to debris damage [2]. This not only serves
as a testament to the blades’ incredible performance, but also
shows that costs of maintenance are drastically reduced with
the switch to composite fan blades.
Formerly, the fan blades of a jet engine were composed
of a titanium or aluminum alloy, mostly for the durability
those materials provided. However, such metals are heavy,
cumbersome, and prone to damage. During flight, engines
may encounter debris and foreign objects that sporadically
fly into the blades, either damaging them or moving past
them and into the combustor, where they can cause massive
damage. Fortunately, the Genx utilizes the aforementioned
variable-bleed valve doors, which remove debris that passes
the fan blades, preventing it from entering the latter stages of
the engine’s combustion process. These valve doors are built
with carbon fiber plastics so as to improve their durability
and reliability, as their operation is essential to the safety of
the engine.
In addition, the blades themselves are made of carbon
fiber materials; a far cry from metal-based blades of past
models. With the replacement of traditional metal alloy
blades, GE had greatly enhanced the blades’ strength and
lifespan as well as their general efficacy. The composite
blades are more shock-resistant and able to withstand much
more foreign object damage (FOD) from debris than their
metal predecessors. Also, “their inherent low density makes
solid composite blades 10% lighter than a hollow titanium
blade,” and “overall, composites are 66% lighter than
titanium …and 100% stronger” [2].
Fan Blade Chamber Housing
The outer casing of the fan is also made of carbon fiber
plastic composites, and it provides drastic improvements
over the older aluminum casings. The design of the casing
utilizes a specific braid-and-weave pattern of carbon
composite fibers and a coating of resin in order to replace
the traditional aluminum alloy material. In addition, a
special thickened middle weave “[provides] a fan-blade
containment layer, eliminating the need for the Kevlar
blanket used on aluminum cases” [2].
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Jason Carney
the engine will stay on aircraft 30% longer than previous
engines, will increase fuel efficiency, decrease various types
of pollution, and decrease operating costs in many ways [9].
All of the perks of the newest generation of jet engines
makes airlines, passengers, and regulatory officials eager for
these engines to become the standard
REFERENCES
[1] (2012). “The GEnx Theatre.” General Electric. [Online]. Available:
http://www.geaviation.com/education/theatre/genx/
[2] M. Mecham. (2012). “GEnx Development Emphasizes Composites,
Combustor Technology.” Aviation Week. [Online]. Available:
http://www.aviationweek.com/aw/jsp_includes/articlePrint.jsp?storyID=ne
ws/aw041706p1.xml&headLine=GEnx%20Development%20Emphasizes%
20Composites,%20Combustor%20Technology
FIGURE 8
THE COMPOSITE OUTER HOUSING OF THE GENX FAN BLADE CHAMBER
[13]
[3] R.J. Stella. (2010). “Picture of Boeing 747.” Airliners.net [Online].
Available:
http://www.airliners.net/photo/Cargolux/Boeing-747-8R7FSCD/1816861/L/
This design greatly reduces the weight of the unit while
also improving its resistance to damage; after over 100
ballistics test were performed on the casing design, it was
shown that the composite case “was more resistant to
ballistic FOD damage than aluminum cases” [2]. Through
the use of carbon fibers in the design of their newest jet
engine, General Electric has significantly reduced the risk
presented by airborne debris, the cost of maintenance, and
the overall weight of then engine, all while greatly
improving its performance.
[4] (2008, March 27). “Choix des moteurs et exclusivités 2.” Aerowebfr.net.
[Online].
Available:
HTTP://WWW.AEROWEBFR.NET/FORUM/AVIATION-CIVILE/3611/4
[5] D. Paiste. (2011, October 23). “GEnx – a new generation of jet
engines.”
Union
Leader.
[Online].
Available:
http://www.unionleader.com/article/20111023/NEWS02/710239963
[6] (2005, July 20). “Driving GE Ecomagination with the Low-Emission
GEnx
Jet
Engine.”
General
Electric.
[Online].
Available:
http://www.geaviation.com/aboutgeae/presscenter/genx/genx_20050720.ht
ml
RE-INVENTING THE JET ENGINE
General Electric spent millions of dollars designing and
building their next generation GEnx jet engine, but what
good is it to the average person? The GEnx allows airlines to
spend less money annually on fuel and maintenance,
lowering the operating costs of all of their aircraft. This, in
turn, keeps flight costs competitive for the consumer. The
GEnx also helps the environment world-wide due to its
decrease in air pollution thanks to its more efficient fuel
mixture and lower burn temperatures. Planes are not going
to stop flying, and providing a safer and more
environmentally friendly solution to propel them will allow
the newest generation of aircraft to operate safely.
Thanks to General Electric’s innovative use of modern
composites, metals can be saved for use in more vital parts
of the aircraft such as the turbines and compressor instead of
being wasted on costly fan blades and housings. The use of
various specialized coatings and lightweight materials
increases fuel efficiency while reducing weight, which saves
airliners money, and reduces the amount of fuel consumed
each year. Fossil fuels are a non-renewable resource, and
providing the most efficient ways to use these fuels is vital
to continuing their use in the years to come.
Finally, the high-bypass ratio of the GEnx decreases the
noise output of the engine by 30%, reducing noise pollution
in areas surrounding large airports. Along with all of the
other innovations General Electric has utilized in the GEnx,
[7](2012). “The GEnx Engine Family.” GE Aviation. [Online]. Available:
http://www.geaviation.com/engines/commercial/genx/combustor.html
[8] M. J. Donachie. (2000). “Titanium: A Technical Guide.” ASM
International.
[Online].
Available:
http://www.knovel.com/web/portal/browse/display?_EXT_KNOVEL_DISP
LAY_bookid=3750
[9] D. P. Brown. (2010, July 8). “Ten Interesting Facts about the GEnx
Engines Used on the Boeing 787 Dreamliner.” Airline Reporter. [Online].
Available:
http://www.airlinereporter.com/2010/07/ten-interesting-factsabout-the-genx-engines-used-on-the-boeing-787-dreamliner/
[10] D. Chung. (1994). Carbon Fiber Composites. Elsevier. [Online].
Available:
http://www.knovel.com/web/portal/browse/display?_EXT_KNOVEL_DISP
LAY_bookid=517&VerticalID=0
[11] “Buckyballs, Diamond and Graphite.” University of Wisconsin.
[Online].
Available:
http://www.chem.wisc.edu/~newtrad/CurrRef/BDGTopic/BDGtext/BDGGr
aph.html
[12] (2011, November 20). “Fan Blades and Inlet Guide Vanes of GEnx2B.”
[Online].
Available:
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Jason Carney
http://en.wikipedia.org/wiki/File:Fan_blades_and_inlet_guide_vanes_of_G
Enx-2B.jpg
[13] (2009, June 16). “Eithad Airways Inks GE Contracts Worth Over
$4.5B.” GE Reports. [Online]. Available: http://www.gereports.com/etihadairways-inks-ge-contracts-worth-over-45b/
ADDITIONAL SOURCES
C. Soutis. (2005, September 22). “Carbon fiber reinforced plastics in
aircraft construction.” International Conference on Recent Advances in
Composite
Materials.
[Online].
Available:
http://www.sciencedirect.com/science/article/pii/S0921509305009780
ACKNOWLEDGEMENTS
Thank you to Nicholas Andes (Chair), Caroline Repola (CoChair), and Nancy Koerbel (Writing Center) for their
assistance. Special thanks to Stephen Gugliociello for his
assistance with editing.
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