aerodynamics assignment a350 vs b787 a.s
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‘Reduction’ is a term heavily used by
the two world’s leading manufacturers
in the production of both the B787 and
A350 XWB. Followed by ‘economic
saving costs’ due to the innovative
technology that enabled automated
manufacturing, high performance
engines, aircraft aerodynamics
improvement and other robust
developments that the airliners will
take full advantage of.
Airbus 350 XWB and Boeing 787
Analising the design approach, materials,
structure and systems used in the two new
generation aircrafts
Submited to: Pat Murray
Alexandra Slabutu
C13758205
B.Eng.Tech. in Aviation Technology
DT 011/2
AIRBUS 350 XWB AND BOEING 787 MAY 9, 2015 ALEXANDRA SLABUTU C13758205
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Declaration
This is an original work. All references and assistance are acknowledged.
Signed:
Date: 12th May 2015
Candidate Name: Alexandra Slabutu
If an assignment or project or part of an assignment or project has been plagiarized
from any source, this will result in a fail for that assignment or project. (DIT, 2011)
AIRBUS 350 XWB AND BOEING 787 MAY 9, 2015 ALEXANDRA SLABUTU C13758205
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Abstract
‘Reduction’ is a term heavily used by the two world’s leading manufacturers in the
production of both B787 and A350 XWB. Followed by economic savings costs due to the
innovative technology that enabled automated manufacturing, high performance engines,
aircraft aerodynamics improvement and other robust developments that the airliners will take
full advantage of. Carbon Fiber Reinforced Pastic (CFRP) materials have revolutionised the
way aircrafts are built, however these pose uncertanties as well in terms to the fuselage
straingth and major repairs.
The advantages that the Dreamliner and the A350 provide to their owner, may be seen as
concerns to the Maintenance Repair and Overaul (MRO) organisations due to the fact that
automation will take over, thus workforce will decrease and also due to the lesser
maintenance checks that these aircrafts will require.
Key words: innovation, technology, aircraft, reliability, savings, cost efficiency, robustness,
advancement, development, next generation, jetliner, fuel efficiency, dreamliner, reduction,
efficiency, composite materials, airlines, emission.
AIRBUS 350 XWB AND BOEING 787 MAY 9, 2015 ALEXANDRA SLABUTU C13758205
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Abbreviations:
CFRP – Carbon Fiber Reinforced Plastic
EBA – Electric Brake Actuator
EH – Electrohydraulic
EHA- Electrohydrostatic
EIS – Entry In Service
EM – Electromechanical
HID – High Intensity Discharge
IATA – International Air Transport Association
LED – Light Emitting Diode
MEA – More Electric Architecture
MRO – Maintenance Repair Overhaul
XWB – Xtra Wide Body
AIRBUS 350 XWB AND BOEING 787 MAY 9, 2015 ALEXANDRA SLABUTU C13758205
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Contents
1. Introduction ............................................................................................................................... 5
2. Boeing 787 Dreamliner vs Airbus 350 XWB .......................................................................... 5
2.1 Design Approach ..................................................................................................................... 5
2.2 Materials and Structure ......................................................................................................... 6
2.3 Systems Arhitecture ................................................................................................................ 9
3. Conclusion ............................................................................................................................... 11
4. References .................................................................................................................................... 13
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1. Introduction
ast paced technology development together with the demand of air travel have imposed a
challege to the world’s largest aircraft manufacturers, Airbus and Boeing. These had to
respond promptly with innovative ideas that would satisfly the industry, in the current and
future economic climate, by projecting new aircraft type designs that would have multiple
capabilities such as: to be fuel efficient, improve performance, environmental friendly, reduce
maintenance costs, reduce weight, incorporate state of art technology, optimising passenger
comfort and most importantly be an overall cost effective aircrafts.
Both the Airbus A350 XWB and the Boeing B787 represent a new approach by the two
companies to commercial air transport. While both share common features of new
technologies, there are distinct differences between them in terms of design, materials,
structures and systems.
The two pioneering aircraft types have been designed and built in close collaboration with the
airliners considerations, in order to respond to their needs and maximise the aircrafts value on
the market. The B787 Dreamliner has however implemented a totally new approach in its
design, being a More Electric Architecture, MEA, wheather the A350 XWB although still
very much technologically improved, it focused more on reliability by adopting many
designes from the A380 and A330 aircraft family types. This gives an advantage to the A350
as all the borrowed systems/designs from the A380 and A330 have proved to be a success
already and moreover communality is highly emphasised in Airbus thus improving airliners
operational costs, meaning that crew training and maintenance costs are utterly reduced.
Throughout this assignment, a thorough analysis will be developed on both the A350 and
B787 focusing on their design philosophy, materials, structure and systems.
Boeing’s B787 aircraft design philosophy is based on life-cycle cost design, ensuring that its
operartors will benefit high reduction in maintenance costs. Boeing’s approach looked at the
costs produced by various factors such as: drag, weight, noise, schedule reliability,
2. Boeing 787 Dreamliner vs Airbus 350 XWB
2.1 Design Approach
AIRBUS 350 XWB AND BOEING 787 MAY 9, 2015 ALEXANDRA SLABUTU C13758205
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develoment and build cost, that affect the aircraft throughout its life time. By doing this they
have introduced two distinct performance measures: maintenance cost and airplane
availability. (Hale, n.d.) Like the B787, the A350 jetliner is designed having the customer’s
needs in mind, providing reliability and reduced maintenance costs. Its smart design
implements a series of the most efficient materials possible for each and every aircraft
component. Apart from the composite and metalic materiales being used, the A350 adapts
other advanced ulta-light alloys such as aluminium-lithium and titanium. These materials
have prolonged the A350 maintenance service checks from six to twelve years, thus saving
revenue for the airliners.
2.2 Materials and Structure
Both aircrafts airframe and structure contain high percentage of composite and titanium
materials (A350: 53% CFRP, 14% Titanium – Fig.1; B787: 50% CFRP, 14% Titanium-
Fig.2) more than their previous aircraft types. These innovative materials have helped reduce
the overall weight of the two aircrafts subsequently reducing their fuel consumption, thus
bringing more profitability to the owner. That being said, the greatest advantage of these
materials is their corrosion and fatigue resistance and strength durability, contrary to the
aluminium materials.
Fig 1. Airbus A350 Materials (Airbus, n/a)
Although composites are not great in dealing with compression loads, it excels in tension.
Compared to aluminium, titanium proved to be prefered to use in areas such as galleys, seat
rails, metallic frames in the lower part of the fuselage and the nose section of the A350 XWB,
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due to its advantages which are mentioned above. Carbon Fiber Reinforced Plastic (CFRP) is
found in the following structures of the A350: window frames, fuselage panels, keel beam
frames, clips, wing box single piece top and bottom covers that are 32m long. The
empennage uses CFRP too. The fuselage innovation used by Airbus is the first time being put
in practice, moving forward from its tradinionl concepts. The aircraft pressurised cabin is
divided into three main distinctive sections which are made of four CFRP panels and one
barrel fuselage design for the non-pressurised aft part of the aircraft, adding improved aircraft
performance. The circumferential joints are assembled in such a way that are not exposed to
the heavy loadead areas like the wing to fuselage section. The thickness of the carbon fiber
composite varies throughout the fusselage structure, requiring higher level of CFRP in areas
that are more prompt to impact like the door surroundings, compared to lower risk areas. This
is a damage tolerance design which is a vital part of the airworthiness regulation that the
aircraft has been subjected to. (F Gaible, 2013)
The 787 and 350 structure include various composite materials such as: glass/carbon hybrid,
fiberglass, carbon laminate which is made of layers of carbon fiber impregnated with a
polymer and carbon sandwich which is similar to a honeycomb shape.
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Fig.2 B787 Material distribution (Hale, n.d.)
In contrast B787 fuselage is purely made of one-piece barrel shape sections, with no
longitudinal splices, improving the aircraft’s weight and maintenance costs. Its assembly was
fully automated, having saved labour and equipment costs. The repair technics are the same
as the ones used on the metallic aircrafts which is using bolted repairs but also offering the
option of bonded composite repairs which allows better aesthetic and aerodynamic finish.
However the bonded repaires are only allowed for temporary fixture, as its not accepted by
the airworthiness authorities. (Mash, 2012) The A350 on the other hand utilises standard
bolted repair concept for structural damages and bonded repairs for minor cosmetic damage.
The skin panels of the A350 and the barrel sections of the B787 use same method of
connection, the conventional fasteners technique and lap joints between them. (Marsh, 2007)
New technologic software has allowed Airbus to inspect all the drilled holes in the A350, in a
more efficiently and faster method. ‘Percephone’ is an ultrasonic inspection tool that detects
possible delamination. A kit made of a mini-tablet, a water spray container and various daisy
probes, enables the operator to check the drilled holes within minutes and connects him/her
automatically to the software. Basically water is sprayed into the hole till is fully filled,
facilitating the coupling between the module and the hole which needs inspection, then the
probe is aimed at the hole. Coloured imaginary is displayed representing different codes such
as red for delaminated hole, orange for contentious cases and green if the hole is correct. This
ultrasonic development not only saves rime, training and maintenance costs it improves
traceability for the inspection of the 36,000 existing holes located on the forward and centre
parts of the aircraft. (F Gaible, 2013, p. 31)
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The two manufacturers rely very much on automated production for building the A350 and
B787 due to the available innovative technologies. 3D printing is one of the techologies that
helped producing around 1000 parts for the A350, giving advantage to “Airbus which has
managed to save money and reduce manufacturing time to meet their required deadlines”.
(KRASSENSTEIN, 2015)
The A350 carbon wing has a span of 64 meters and includes winglets and high-lift devices.
An approximate speed of Mach 0.85, similar to the speed of the B787, is achieved due to the
aerodynamically efficient 33 degree swept wing.
2.3 Systems Arhitecture
Boeing’s ambitious system design on the Dreamliner, has a new approach that no other large
comercial aircraft has conceived before, a more electric system arhitecture that essentialy
doesn’s require bleed air from its two engine type variations: the Rolls-Royce Trent 1000/
GNnx. The electric operating systems in the 787 are: hydraulic pumps, cabin pressurisation,
engine start, APU start and wing ice protection. Only one system still uses bleed air, the anti-
ice system for the engine inlets. Unlike the conventional APU which drives pneumatic load
compressor the new APU uses a starter generator that promises to be four times more
reliable. The engines also benefit of electrical power generation, a fundament change that
eliminates the pneumatic starter from the engine. Ducts, valves, heat shields, overheat
monitoring systems and duct burst protection systems are the functions that have been
removed from the 787 airframe due to the bleedless engine system.
Airbus A380 system designs have contributed to the newer jetliner build concepts which
together with other advanced technologies have made the A350 the most sofisticated aircraft
in the Airbus family fleet. Its hydraulic systems is an example of how A380 influenced the
manufacturer to implement it again, as it proved to be a robust design that the airliners were
satisfied with its performance. The system comprises of two hydraulic circuits contrary to the
three circuits that the rest of the Airbus aircrafts have. Flight controls, nose wheel steering
and landing gear actuation are some of the systems that are powered by these hydraulic
circuits. Moreover the A350 XWB has a simplified fuel system with fewer pumps and valves.
These reductions like the B787 add advantageous benefits for the air carriers when operates
them commercially, saving capital due to weight saving and lesser maintenance visits. The
AIRBUS 350 XWB AND BOEING 787 MAY 9, 2015 ALEXANDRA SLABUTU C13758205
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manufacturers also benefit from having fewer systems for the aircrafts as it improves their
production to in service operation. (Airbus, n/a) The 787 and 350 have incorporated a 5000
psi system operating pressure, similar to the A380.
Fly-by-wire is used in both B787 and A350, replacing the mechanical system of cables and
pulleys with electrical signals that actuate the control surfaces. The Dreamliner incorporates
triple redundant systems to move its control surfaces, the third being an hydraulic system
compartmentalised with valves, and pressure is maintained using electrical compressors. The
fly-by-wire in the A350 uses a fully electrical three axis flight controls, providing extra flight
safety, reduction of mechanical parts and reduced pilot workload. From the commercial
operational point of view the A350 has a huge advantige over the Dreamliner in terms of the
fly-by-wire system, by providing the communality experience to the flight deck crew which
Airbus has incorporated throughout its entire aircraft family for many years.
The primary flight control system in the A350 includes a mix of electrohydraulic (EH) and
advanced electrohydrostatic (EHA) actuators to control the rudder, aileron, elevator and
spoiler flight surfaces. The Dreamliner adapts a very similar system with the exception that it
has an electromechanical (EM) servoactuators instead of the EHA actuator, which helps
control the flight surfaces. (Moog, 2013)
Electric brakes is an application of the MEA on the Dreamliner, a technological advancement
from the hydraulically actuated brakes (Hale, n.d.). Four independent electric brake actuators
(EBA) are available per wheel, allowing one of them to act as inoperative in the likely event
of a failure. By having this type of electrical system Boeing finds it easier monitoring the
status and health of the aircraft in general compared to the pneumatic or hydraulic systems.
The advantages that the airlines can benefit from monitoring the brakes are: electrical
monitoring of brake wear, fault detection and isolation, the ability to eliminate scheduled
visual brake wear inspections and extended parking times.
In regard to the 787’s cabin design, it can be noticed that the mechanical window shades have
been replaced with electro-cromatic dimmable windows which have a projected life of more
than 20 years. In addition high-intensity discharge (HID) and light emitting diode (LED)
lighting have been implemented in all cabins, flight deck and on aircraft exterior, having a
life longevity more that its counterparts due to no filament presence.
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3. Conclusion
The main scope of having developing these technologically advanced aircrafts is to respond
to today’s rapid growth in terms of transport by air demand and adapt to the technology
evolution. Close collaboration have been maintened between the airliners and the
manufacturers in order to tailor their needs in the production of the B787 and A350 XWB.
This assignement has been looked at the various materials used for the aircraft’s structure, the
systems and the design philosophy approch used on both the 787 and 350. The changes
implemented are very bold and promising, especially with the 787 MEA, wheather the 350
has adopted some of the elements from its precessors, the A380 and A330, keeping it more
conventionally focused. However the biggest change is the use of composite materials, no
other commercial aircrafts have used these high amounts of CFRP before. Its advantages are
tremendeous and airliners find it very attractive. Reliability and having economic costs
reduced are buzz words constantly used by the two world leading manufacturers. Composite
materials have never been
used on this scale before,
therefore it comes with
many uncertanties that the
aviation industry take the
responsability for and yet
have no answer.
Fig.3 MRO Costs (IATA,
2014)
The obvious concerns
relate to the durability of
the material under
conditions that cannot be
tested by the
manufacturers, such as how
many repairs of different
types can the structure
sustain until it breaks down
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(Marsh, 2012). After an impact the composite materials unlike metals, don’t show sign at the
surface, that the laminate has suffered damage, “...composites can spring back from low-
energy impact such that damage several plies down within the laminate can be hidden behind
an apparently unharmed surface.” (Marsh, 2012) Despite this Boeing and Airbus research
have found a solution based on a ultrasonic hand held enquipment which enaibles the
technician to detect if the laminate is damaged or not.
Reduced aircraft parts due to the innovative materials and advanced systems, lesser
workforce due to automation and prolonged maintenace check intervals due to the
technologies involved in building these two aircrafts, are some of the great achievements
established by Boeing and Airbus and that the airliners avail from. Despite these great
attributes, the Maintenance Repair and Overhaul Market may see them as challenges.
However according to the (IATA, 2014) report “Global MRO spend in 2013 was estimated at
$ 131 Bill., including overhead. Civil air transport (commercial) was valued at 46% ($60.7
Bill.). Market size is estimated to reach $89 Bill. in 2023.” (Fig 3.)
The good news for the MRO market is that the aircraft retirement will nearly double in a
decade time, due to the more efficient and young aircraft’s EIS. This means that the
aftermarket will benefit high pool of spare parts which will increase availability and spend on
surplus parts, composed at 65% of engine parts.
Regardless the relentless efforts made by Airbus and Boeing to help the MRO and other
material/parts suppliers to train on the technologies that are being used in the two new
aircrafts, it will be a challenge that will take some time until every destination that the two
will touch down, will have the adequent training and equipment required for maintening the
350 and 787. Also the new regulatory rules focusing on both aircrafts it will probably face
problems as differences may arise between the various authorities and its implementation and
adaptation may take time and capital to develop.
Nonetheless, Boeing and Airbus have developed three variants, the 787-8/9/10 and 350-
800/900/1000, that will provide their customers with ultra long ranges and extra passenger
capacity. The two manufacturers promise a 20% savings in the operation costs, and 20%
fewer emissions that will add value to the airline business.
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4. References
Airbus, n/a. Innovation. [Online]
Available at: www.a350xwb.com/innovation/ [Accessed 08 May 2015].
F Gaible, P. G., 2013. Intelligent airframe design. FAST, June, pp. 28-31.
Hale, J., n.d. Boeing. [Online]
Available at:
http://www.boeing.com/commercial/aeromagazine/articles/qtr_4_06/AERO_Q406_article4.pdf
[Accessed 05 05 2015].
IATA, 2014. Airline Maintenance Cost Executive Commentary, Montreal: IATA.
KRASSENSTEIN, B., 2015. 3dprinting. [Online]
Available at: http://3dprint.com/63169/airbus-a350-xwb-3d-print/
[Accessed 8 May 2015].
Marsh, G., 2007. Airbus takes on Boeing with reinforced plastic A350 XWB. Reinforced Plastics, n/a
December, p. 27.
Marsh, G., 2012. The challenge of composite fuselage repair. Reinforced plastics, May, pp. 30-35.
Mash, G., 2012. The challenge of composite fuselage repair. Reinforced Plastics, p. 31.
Moog, 2013. Moog. [Online]
Available at: http://www.moog.com/markets/aircraft/civil-aircraft/commercial-transport/system-
provider-for-the-boeing-787-dreamliner/ [Accessed 10 May 2015].
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