Final Report

The Design and Layout of Future Long-Range
Commercial Airliners
Christopher Andrew Wardle

Final YearProjectReport - ChristopherWardle @00303673
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UNIVERSITY OF SALFORD
School of Computing Science and Engineering
Name of Student: Christopher Wardle
Course Code: H490
Title of Project: The Designand Layout of Future Long-Range Commercial
Airliners
I certify that this report is my own work. I have properly acknowledged all material that
has been used from other sources, references etc.
Signature of Student: Date: 27/12/13
Official Stamp:
Submission Date (to be entered by relevant School Office staff):

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Abstract
In this project, four plausible long-range, model-sized commercial aircraft are designed
and manufactured for the purpose of testing their aerodynamic characteristics in a
subsonic wind tunnel. The designs are brought to life using Computer-Aided-Design,
before being constructed via the use of a 3D printer. In order to ensure cost
effectiveness and future proofing, each of the four designs must be consecutively
applied to just one re-configurable fuselage. This fuselage must also have the ability to
accommodate a vast variety of potential re-configurations during future re-use. Each of
the four configurations must be of sufficient quality, such that the relevance of wing-
body blending, as well as the overall layout of their key components, can be analysed
for their potential aerodynamic benefits.
Acknowledgements
Dr Phillip Atcliffe_________________________________________Project Supervisor
Who has provided guidance on project direction, helpful solutions and definitive
intentions.
Dr Tony Jones__________________________________________Head of Engineering
Who has aided in finding a suitable balance between the original project and financial
feasibility for 3D printing.
Mike Penny____________________________________Aerodynamics Lab Technician
Who has provided guidance on the use of modelling techniques for wind tunnel testing.
Mike Mappin__________________________________CAD & 3D Printing Technician
Who has provided help with negotiations and adaptations to the project, as well as help
in the Computer-Aided-Design, 3D printing and model construction departments.

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Contents
Introduction_______________________________________________________Page 5
Gant chart________________________________________________________Page 8
Project Plan_______________________________________________________Page 9
Methodology_____________________________________________________Page 12
Current Progress__________________________________________________Page 15
Literature Review_________________________________________________Page 20
Initial Designs____________________________________________________Page 35
Initial Fuselage Design_____________________________________________Page 36
Solidworks_______________________________________________________Page 38
Concept 1________________________________________________________Page 41
Concept 2________________________________________________________Page 43
Concept 3________________________________________________________Page 45
Concept 4________________________________________________________Page 48
The Reconfigurable Fuselage________________________________________Page 50

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Construction Phase________________________________________________Page 54
Model Evaluation_________________________________________________Page 55
References_______________________________________________________Page 58
Please note that due to the design based nature of the project, the Appendices have been
included in a separate booklet to make cross-referencing easier.

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Introduction
The “Introduction” section, gives a brief history of aircraft design considerations, as
well as an outlook as to what this project will focus on. Please refer to Appendix A for
this section.
The design and development of commercial aircraft has never been considered a quick
process and this is especially true in modern day aviation, with new computerized
systems and advanced aerodynamics making the task continuously more challenging.
With the global fuel crisis becoming ever-more significant, it is essential that aircraft
manufacturers begin to focus more on improving the efficiency of the aircraft they
produce. With no obvious alternative source of energy to turn to, designers must
consider how their aircraft use fuel effectively and one way to do this is by altering the
aerodynamics. Currently, civil long-range transport aircraft, such as the Airbus A380-
800 (Figure 1.1) or the Boeing 747-400 (Figure 1.2), adopt a conventional layout which
involves positioning the main wings just ahead of the Centre of Gravity (about half way
along the body) for longitudinal stability, and smaller stabilators (or tailplane) at the
rear of the body in order to produce an effective moment arm during pitching. The
engines are typically hung below the wings, just below the C of G and the tail fin again
at the rear, though just head of the tailplane to avoid any disruptive wash during
elevator operation. This typical layout gives a fuselage with up to nine large extrusions,
all of which cause excessive amounts of form drag. Couple this with smaller extrusions
such as winglets, avionics fins and hydraulic fairings and the drag starts to pose a
significant threat to the aerodynamic efficiency.
The most obvious solution to eradicate any unwanted extrusions, is to blend them all
into one shape. This produces a design not dissimilar to the Grumman B-2 Spirit
(Figure 1.3), a shape most commonly known as the “flying wing”. The fuselage and the

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main wings are fully blended into one continuous form, subsequently giving enough
room for the engines to be stored inside the structure near the tail. The aerofoil used for
the main wings is subtly modified to include a small lip on the trailing edge that
effectively acts as the stabilators or tailplane (Figure 1.4). Focusing particularly on the
B-2 Spirit, the use of a tail fin and winglets was neglected since the aircraft produced a
satisfactory amount of lift whilst also remaining stable on the lateral and transvers axis.
Overall this eliminated all extrusions on the aircraft, meaning the whole aircraft could
be considered as a single entity. The design was most acceptable by military standards,
however civil safety standards were and still are far stricter and thus has yet to be
adopted commercially.
Certification in the aviation industry can make or break an aircraft manufacturer,
regardless of its size or heritage. A recent example, is that of the Beechcraft Starship
(Figure 1.5). This aircraft adopted a “canard” design, with the main wings at the rear of
the fuse, canard fore-planes on the nose, rear-facing turbo-props extruding upwards
from the upper surface of the main wings and unconventionally large winglets that acted
jointly as two small tail fins. The aircraft took a great deal of time to certify due to its
alien design, a time that Beechcraft’s customers were not prepared to wait out and
ultimately the project fell apart as alternatives from Cessna and Piper were sought.
All aircraft are designed using wind-tunnel models that aid in the development of their
aerodynamic characteristics and qualities (Figure 1.6). With numerous design
alternatives in question, especially when developing a brand new aircraft, it can often be
quite a financial burden to the manufacturer to continuously produce these ever-
changing models. Each model takes a considerable amount of time and attention, since
the quality must be sufficient enough to provide valid results and the shape must echo
that of the real aircraft as accurately as possible.

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This project looks into the design of four plausible, future, long-range commercial
aircraft and discusses the extent to which the designs could exist. Subsequently, the
project will discuss the feasibility of manufacturing an accurate wind tunnel model via
the use of 3D printing, that can not only provide valid results, but can also be
reconfigured to host all four of the designs consecutively. Finally, the reusability of
such a reconfigurable model and the limitations associated, will be discussed in order to
establish the relevance and benefits of the project.

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Gantt chart
The “Gant chart” shows the project’s primary intentions and course of action. It also
provides an early outlook as to how the given time constraints will be used most
effectively.
Student:ChristopherWardleMeetings/WorkKey
Compulsory/Intentional
Supervisor:DrPhillipAtcliffeOptional
Semester1Inter-SemesterBreakSemester2
WeekNumber→12345678911113-15111122222222222333
Task↓012678901234567890123
Meetwithsupervisor
Composeprojectplan
Researcha/cdesign
Writeliteraturereview
Begin2Da/cdesigns
DevelopSolidworksskills
Finalise2DDesigns
Beginmodelling3Da/cdesigns
Meetwith3Dprinttechnician
Meetwithaerotechnician
Obtainallpermissions
Begin3Dprinting
Finalisemodel/parts
WriteFinalReport

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Project Plan
The Design and Layout of Future Long-Range
Commercial Airliners
Student: Christopher Wardle @00303673
Supervisor: Dr Phillip Atcliffe
Introduction
Aircraft design has never been considered a quick process, understandably due to the
numerous variables and limitations involved. The greater the change, the longer and
more challenging the certification process. Certification times can make or break a
manufacturer and delays can ultimately destroy a product before it has even left the
factory.
This project focuses on four plausible commercial aircraft designs, each with varying
degrees of wing-body blending, that are then to be 3D printed for use as wind tunnel
models. Additionally, each of the four designs must be consecutively applied to just one
re-configurable fuselage, in order to reduce manufacturing costs and to allow the model
to be fully reusable in future years. Each design must achieve a high standard of quality,
such that it can be tested aerodynamically.

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Objectives
The following objectives outline the primary project focus points:
 To design four plausible, long-range commercial jet aircraft
 To design a single fuselage that can accommodate the four different design
extremes
 To re-produce the designs by the means of CAD and 3D printing
 To ensure that the 3D models are of high quality, such that they can be tested
aerodynamically in future years
 To ensure that the interchangeable sections of the fuselage allow for a vast
variety of reconfigurations during future re-use
 To evaluate the relevance and benefits of 3D printing for aerodynamic model
testing
Sub-topics
After the primary focuses have been achieved, the following subsidiary objectives may
also be considered:
 The feasibility of future aircraft design
 The potential behind 3D printing future transport
Equipment Requirements
In order to achieve the highest quality results, the following equipment is required for
this project:
 Hand-Sketching tools for initial designs
 Dassault Systems - Solidworks 2010 for 2D to 3D conversion and design
specifics
 3D Printer for manufacturing the designs
 Workshop tools for build adjustments and surface quality improvements

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 Wind tunnel brackets and measuring equipment to ensure the model is useable
in the available facilities
SolidWorks 2010
Solidworks is a Computer-Aided-Design suite (or 3D design Software) made my
Dassault Systems. The program features a number of advanced tools that allow the user
to sculpt their product quickly in three dimensions. Solidworks has the added bonus of
being able to save a design as a .STL file, a common format for use with 3D printers.
The program is built specifically for engineering and thus includes standardized
industrial parts and measurements. It also has the added bonus of a computational fluid
dynamics (CFD) simulation built in as a plugin, which can significantly reduce
development costs for manufacturers.
3D Printing
3D Printing takes the .STL file mentioned earlier from Solidworks (and other
comparable CAD packages) and constructs the model in fine layers. Heated rolls of
plastic are injected through a small nozzle onto a crafting board. The nozzle is free to
move under the x, y and z axis allowing it to “draw” the model in 3D. The process is
relatively slow; large models taking up to a week to print, and the surface quality may
not be initially satisfactory for wind tunnel testing. Despite this, 3D printing offers the
ability to manufacture far more complex shapes at a fraction of the labour cost. There is
also the possibility to 3D print moving parts fully assembled within their housings,
eliminating the construction phase.

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Methodology
The “Methodology” section is an in depth plan of the work intended to be completed
during the time the project is in motion. The section is written considering the project
adaptations that have developed from the original idea. See “Current Progress” for
more details on the changes that have occurred.
The overall approach to begin with, was to stay ahead of schedule whilst ensuring that
every area had substantial and relevant content. This approach has remained a key
aspect of the project to date, with the intention of maintaining this until its completion.
Initially a project plan and Gantt chart must be constructed as this would provide a far
clearer outlook of the deadlines and milestones that lay ahead and as well as an idea of
the timescale for each section of the project. Details for the specific deadlines and
milestones would be obtained during an initial meeting with the project supervisor, held
within the first week. With a general idea of the tasks needed to be done, progress could
be made towards the project itself. The report was to be written and updated over the
entire time that the project was in motion.
The first most logical step would be to carry out some research on aircraft design such
as wing-body blending, aircraft layouts such as delta-wing and Canard and aircraft
certification. Knowledge from these areas was to be accumulated and presented in this
report as the literature review. The literature review, though an initial task, was to be
updated as the project continued and adapted.
After sufficient knowledge on the topic had been gained, initial designs were to be
sketched, focusing primarily on a fuselage design that could accommodate the four
vastly differing wings shapes and positions. The fuselage design must also have been
able to host a vast number of alternative designs in order to future proof the model.

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Whilst designing the aircraft it was essential that this time was also used to gain an
understanding of Solidworks 2010. The CAD software presented a relatively typical
interface given prior knowledge of other 3D programs, however further understanding
would be required in order to gain full potential of the suite and ultimately produce the
finest quality models. Once the desired understanding of the program had been
obtained, the designs would be finalised on paper, before modelling them in
Solidworks. It is likely, at this stage, that the designs would require modifying, due to
program or fuselage compatibility limitations. Every sketch and progression in
Solidworks was to be recorded and included in the appendices of both the interim and
final report. A meeting with the aero lab technician would be required in order to obtain
measurements for the subsonic wind tunnel and its brackets. The most logical scale for
the models would be as large as possible, whilst still allowing for a fair amount of room
between the wing tips and the side, in order to avoid any pressure drops that would
invalidate tests. The model would have to be mounted up-side down due to the nature of
the wind tunnel, meaning that the brackets would have to be rendered on the underside
of the model for fixing.
Depending on the timing at this stage, there would be two options available when
considering the printing of the models. The first option would be to render the first
model only and obtain the necessary permissions for printing, based on cost
implications. The time taken for the first model to print could then be used to continue
rendering the other three aircraft. This would be the most effective use of time and the
least risky, since the models would take around one week each to print and in the event
of any obstacles (financial or construction based), only one of the four models would
require attention. The second option would be to render all four models and attempt to
print the whole batch at once. This would greatly reduce the paperwork required for

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permissions, but would be far more likely to cause problems due to financial limitations.
A problem with time management would also arise due to a potential four week printing
time.
Given that the first option was chosen and the models were individually printed, the
resulting print would have to be examined for aero-test validity. This means that due to
the “layered” construction technique of 3D printing, the surface of the model may have
to be improved by means of sanding or filling, in order to eliminate disrupted airflow
due to surface quality.
Provided that the parts for first model would be of satisfactory condition, the remaining
three models were to be printed and finished in the same manner. Due to the limited size
of the printing platform, the fuselage and wings would be produced in a number of
separate parts. These separate parts were to be aligned and glued accurately, such that
they would form one continuous shape. Locking pins would need to be fashioned from a
thin metal dowel that would pull all interchangeable parts together and onto the
fuselage, whilst holding them securely in place during wind-tunnel testing.
The remaining time would be used to evaluate the models and their limitations in the
final report, with the possibility of expansion into the relevant sub-topics.

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Current Progress
“Current Progress” gives a brief outline of all the work done, any problems faced
along the way and how those problems were rectified. Unlike the “Methodology”, the
“Current Progress” section takes into account the original project and all of its
subsequent adaptations, explaining how and why they came about.
Firstly, an initial meeting was held with the project supervisor where parameters for the
project were discussed and a general direction was given to kick-start the project.
Following this, a project plan was constructed in order to more clearly define its
purpose and desired outcome. The project plan allowed for an initial observation of
what was expected from the project, but also created scope for subsidiary topics, that
could be considered provided there was sufficient time. The plan was then coupled with
a comprehensive Gantt chart, so as to give an idea of the time scale in question along
with a guideline as to how best use that time effectively. After completing the Gantt
chart, it was clear that the project was ambitious, required a fair amount of dedication
aside from other modules, but most importantly was feasible within the given timescale.
With both the project plan and the Gantt chart in place, the next step was to produce a
literature review, as this would highlight the project variables and limitations as well as
knowledge of others work in the area. The literature review began relatively general,
with consideration of aircraft design as a whole. Following this, more specific design
aspects were focused on, in order to provide a more in depth approach to the projects’
aircraft designs. Certification completed the generalised literature section, with an idea
of some of the potential limitations that design manufacturers could face. The review as
a whole was concluded with industry examples as a reinforcement to ideas mentioned in
earlier sections.

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A completed project plan, Gantt chart and Literature review provided the essential
information that was required in order to produce independent work. Despite this, it was
necessary to compose another meeting with the supervisor, so as to establish the more
specific details on the aircraft designs themselves. Design parameters involving wing
positions, the extent of wing- body blending and the relevance of smaller details such as
engines, were discussed. The meeting was concluded with the idea that four aircraft
were to be designed, as this would give the best balance of data vs overall timescale for
the project. The lack of a fifth model would also reduce the cost implication of the
project, reducing the chance of financial obstacles, later down the line.
The remaining parameters were left down to choice. Provided that the aircraft designs
were realistic, the positioning of the wings, the number of aerofoils and the details
involved were unrestricted. Ideally, each aircraft would be designed using formulas and
methods extracted from other modules, as this would certify the aircraft for real flight.
This method would also reflect more realistically on modern industry standards,
however given the timescale of the project, it simply wasn’t possible to do so and thus a
more casual approach to the design was adopted. This wasn’t a major issue and
certainly didn’t pose a threat to the project as the intention remained to test the wing-
body blending and layout of the aircraft, as oppose to determining the static and
dynamic stability of the aircraft during flight. Later on in the project, certain design
parameters would become fixed in order to improve the validity of the data analysis.
The following weeks involved frequent meetings with the supervisor, in order to
provide progress updates and to discuss any queries that arose along the way. Alongside
designing the four aircraft, it was necessary to learn how to use SolidWorks 2010, the
CAD program that was to be used with the 3D printer to produce the models.
Thankfully, due to prior knowledge of multiple alternative CAD programs, the process

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was swift and the first model was ready for printing towards the end of semester one. A
meeting with the aero technician was necessary so as to get some figures for the wind
tunnel and ultimately scale the four models correctly. This left one last meeting with the
head of Engineering in order to obtain the funding to print the models.
Numerous problems arose at this stage as the project bared no future use for studies at
the University. This would not normally be a major issue, however with the project
costing around £3000 in 3D printing material, it was made apparent that the project
needed to be adapted so that it could in some way, be re-used for future analysis. A
secondary problem was stated that there were too many design variables, thus making
the potential data analysis invalid, likewise the surface finish of 3D printed models
would be theoretically unsuitable for aerodynamics testing. Given the time and effort
that had already been spent on the project, along with the vastly reduced available time
remaining, changing the project entirely was out of the question. It was therefore
essential that the project adapted to rectify the given problems.
Firstly, it was decided that all four aircraft designs were to be created on one single
fuselage. This would vastly reduce the cost implications but more importantly would
allow that fuselage to be re-used in later years, with other wings and attachments. This
coupled nicely with the new fixed parameters that had been introduced. The single
fuselage would mean that any aerodynamic changes would not be due to the body itself,
but instead due to the wing shape and the blending of its extrusions. Likewise, it was
agreed that the wing and fin areas would bare a strong similarity, so that the
aerodynamic characteristics purely focused on their blending and position. Of course,
the surface areas would not remain identical on each of the models, as this would mean
reducing the wingspan or chord in order to account for the extra blending – an arguably
contradictive solution.

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Finally, the surface finish of the models was to be improved either by sanding, or by
applying a thin coating of filler to eradicate any anomalous results that might occur due
to the “layered” surface.
With these adaptations in place, the project was given permission to continue and
though the obstacles had caused delays, the project remained on time.
After a considerable amount of work over the inter-semester break, the four aircraft
designs which could be applied onto the single interchangeable fuselage, were ready for
some final adjustments. A meeting with the CAD technician also highlighted some risks
about the security of the interchangeable parts and the removal of those parts that did
not fully intersect the body. Given this discussion, the models were adapted to include
narrow tunnels that pierced each part allowing for the use of locking pins.
With the final designs agreed upon and converted to .STL format ready for printing, the
necessary permissions were once more obtained, this time for a fully re-usable wind
tunnel model, with a significantly reduced £1997 cost implication. Since the project
adaptation and model redesign had caused a considerable delay, it was now necessary to
print the parts for all four models consecutively and as quickly as possible. The total
build time for the project was a rather gargantuan 430 hours, but thankfully by using
two printers simultaneously day and night, the parts were ready for assembly with
plenty of time remaining before the end of semester two. Due to the limited size of the
3D printing pad, many of the features were in multiple parts and required assembly.
This caused further delays waiting for adhesives to set over night, before each feature
could be sanded and tested for design assembly.
With all the necessary features fully assembled, the designs began to take shape and
work could begin on adjusting each part so that the interchangeable model could be

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reconfigured easily. Due to adhesive expansion, some of the parts required adjusting in
order to assembly and disassemble them easily, despite the measurements forming a
perfect fit in Solidworks. The locking pins that would hold each model together were
cut and applied individually, to ensure that they too were easy to insert or remove.
Finally, the surface of the fuselage and each part was smoothened with P240 sandpaper,
so as to remove any irregularities ready for testing.
The model was now effortless to reconfigure and the practical aspect of the project was
completed. A final meeting was arranged with the project supervisor, in order to review
the outcome of the practical project. At this point it was agreed upon that sufficient
work had been done already to complete the written dissertation. This meant that no
aerodynamic testing was necessary and instead the project would become about the
designing of the models and how it was possible to apply such extreme design changes
to one fuselage. With this final adaptation in mind, the written report was modified to
focus primarily on the design of the four aircraft, reconfigurable wind tunnel model and
to evaluate the effectiveness of 3D printing.

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Literature Review
The “Literature Review” deals with literature relevant to the project aims and
objectives, whilst improving an understanding of the design and certification criteria
involved. Please refer to Appendix B for this section.
This particular literature review talks about general aircraft design, before honing in on
more specific design considerations and finally examples that the current industry is
proposing and developing.
General Aircraft Layout Configurations
The Aerodynamic silhouette of an aircraft determines its speed, manoeuvrability, range
and operating cost. Aircraft that operate at the higher end of the subsonic flight regime,
such as those that this project focuses on, usually require largely swept or very thin
wings to achieve a low drag coefficient. This means that the base structures must be
able to withstand torque based and inertial stresses: a strengthening that adds weight to
the aircraft. This extra weight means the propulsion system must run at a higher setting,
which in turn uses more fuel and thus a balance must be determined for optimum
efficiency [1].
For the past 40 years, commercial jet transport design has remained an evolutionary
process. This evolutionary design originates from aircraft such as the De Havilland
Comet (Figure 1.1), with the only major adaptation being the conversion from wing
buried engines, to engine pods under the wings or on the tail. Even this minor adaption
originates from the Boeing 707 (Figure 1.2), despite the introduction and vast
improvement of computer aided design and computational fluid dynamics. There have
been many performance and structural enhancements, particularly in the past decade,
with the introduction of high-bypass turbofan engines (Figure 1.3) and composite

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materials, but the positioning and construction of the aircraft is still comparably
traditional. The main changes to commercial aircraft design have been far more
internally based, with improvements in hydraulics, avionics and reliability. This has
meant that an aircraft with specifications such as the Comet, which at the time was used
for long-haul flights albeit with numerous fuel stops, would now be considered a
domestic or short-haul aircraft.
Even in the early days of commercial jet travel, designers were constantly searching for
more efficient layout configurations, which lead to numerous unconventional designs.
With the invention of the turbojet (Figure 1.4), engines could now be concealed within
the structure of the aircraft, without the problem of large propeller blades protruding
through the fuselage. Some configurations consisted of multiple fuselages spread over
the main wings (Figure 1.5). This allowed stricter safety standards such as evacuation
times, to be met despite increasing passenger payload numbers. The downside was that
boundary layers from intersecting geometry would interfere with themselves and the
design required numerous structural enhancements to overcome the torque effect
between the two or more fuselages. This would add a considerable amount of weight to
the aircraft as well as undesirable aerodynamic characteristics and has thus not yet been
proposed as a serious replacement for the conventional single fuselage design. Due to
the fact that the models for this project are to be centralised around one common
fuselage, the rest of this review will focus only on single fuselage configurations.
One of these configurations, which has become more common in recent years is known
as a Canard (Figure 1.6). This consists of a single fuselage with the main wings situated
towards the rear and the smaller stabilators towards the nose. The engines are typically
placed at the rear of the aircraft also, sometimes within the tail, or above the main
wings, as this brings the Centre of Gravity (C of G) closer to the wing quarter chord

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allowing for a more typical longitudinal stability. Likewise, it is not uncommon for the
wings to be forward swept, in order to bring the aerodynamic centre closer to the C of
G. More recent canard concepts tend to locate the engines above the wings. This is
primarily due to the fact that ground strike may occur on rotation if the engines were
situated below the wings, but also because high bypass turbofans are much larger in
diameter than the turbojet engines they replace, thus there is usually insufficient space
within the tail of the fuselage to store them. The alternative positioning of the stabilators
leads to reduced trim required during flight. This in turn reduces drag and thus fuel
consumption. However Canards are often naturally more unstable than the equivalent
conventional layout. They are also more prone to unexpected flight characteristics such
as loss of lift, should the wash from the stabilators disrupt the airflow over the main
wings. Likewise, there is a risk of nose-up overturning due to stalling of the main wings
whilst the stabilators are generating lift.
A second proposed configuration is the “Span Loader” (Figure 1.7), an idea originally
proposed by Junkers as early as 1910. This, as the name suggests, spreads the payload
over both the fuselage and the length of the wings. Because of this, large fuel tanks may
need to be placed on the wing tips as their typical location within the wing structure, has
been occupied by cargo or passengers. Like the multi-fuselage configuration, this design
focuses more on reducing structural stress due to inertia, typically caused by one single
central force (the mass) pulling down, opposing the remaining two “sandwiching”
forces (wing lift) pulling up. The reduced structural stress would allow in a weight
saving of around 10%, however the positioning of large fuel tanks on the tips of the
wings would significantly increase the overall form and skin friction drag of the aircraft.
Also, with the engine intake geometry of high bypass turbofans being considerably
larger than that of turbojets, the main wings would have to be excessively bulky in order

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to provide sufficient room for the engines to be stored within the structure. With that in
mind, there is no reason, with this particular configuration, why the engines could not
be situated below or above the wings in a more typical manner. Another problem posed,
is the safety of such a congested payload distribution. Especially in the case of
passenger transport, there is very little available space to locate the emergency exits if
the payload is in the wings. As the majority of the available body surface is horizontal,
this would require some form of vertical evacuation.
The “span loader” configuration is not dissimilar to the extreme known as the “flying-
wing” or the “blended-wing body” concept (Figure 1.8). This configuration places
passengers in an “auditorium” manner, with the fuselage of the aircraft gradually
expanding to the tips of the wings. This produces a delta-wing shape when viewed from
the top-down and aims to blend all the major parts of the aircraft into one fluid form. In
order to produce the desired tail fin moment arm, the main wings of the aircraft are
often significantly swept and located as far back as possible. Large winglets are then
situated on the wing tips and co-act as tail fins for transverse stability. Placing the tail
fins on the rear of the fuselage in this configuration is normally unwise as the tail is
often too close to the C of G. The tail plane itself is entirely neglected since the main
wings are situated at the rear like the Canard design. However, it is necessary for the
aerofoil used on the main wings to be adapted so as to have a small lip on the trailing
edge, to counter the lift moment around the C of G. Even with the use of high bypass
turbofans, there is usually sufficient room within the rear section of the structure to store
the engines, since the depth of the wing roots is that of the fuselage diameter. Despite
this, the engines of many blended-wing body concepts are situated above the structure
at the rear, which is most likely due to intake geometry requirements. This configuration
has become increasingly popular in recent years with Boeing, Airbus and McDonnell-

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Douglas presenting concepts for the not too distant future. The interest in the design is
motivated by the improvement of the aerodynamic efficiency of the active boundary
layer and its associated control systems, whilst also increasing the passenger capacity of
an aircraft that will fit in today’s airports. Despite this, there are theories that the
configuration may actually be less aerodynamically efficient than the current
convention due to the increased wing thickness and delta wing planform.
The “Tandem-wing” (Figure 1.9) configuration mimics a conventional design far more
so than the layouts described above. A single fuselage is “sandwiched” between the
swept-back main wings, which are located towards the front of the aircraft. The engine
pods are hung below the main wings and a tail fin extrudes vertically from the rear of
the fuselage. The tail fin itself however, is swept forwards and an unconventionally
large “T-tail” with a span equal to that of the main wings also sweeps forwards. In some
iterations of the design, the T-tail and main wings are joined for enhanced structural
integrity. The design allows for greater tolerance to C of G movement, as well as a
structural weight reduction due to the reduced bending stresses.
All of the design configurations mentioned above have the added benefit of a reduced
wingspan, whilst retaining the desired wing aspect ratio. This gives an overall reduced
drag during flight posing the idea that any one of these concepts could be developed
commercially. The aircraft have currently not been accepted commercially however, as
they are generally far from airworthy due to their multiple aerodynamic and structural
uncertainties [2].

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Specific Design Considerations
Fuselage Design
The fuselage will remain a standardized centrepiece for all four designs. Despite this,
there is very little to vary in terms of aerodynamics. Attention can therefore be diverted
to designing a fuselage that would be both beneficial internally and realistically feasible
to manufacture. When considering double-decker fuselages typical of long-haul
operations, there are generally three different configurations available.
The first configuration (Figure 2.1) places two tubular decks side-by-side, with the
interconnecting walls being open or non-existent. This creates a relatively wide fuselage
as the outer skin wraps around the two tubular cabins, forming an elliptical shape on the
exterior when viewed head-on. This type of design may be beneficial for a hybrid
between a conventional layout and a flying wing configuration since the wide fuselage
could be more easily integrated into the wings.
The second configuration (Figure 2.2) places one deck above the other, a far more
typical layout when considering double-decker aircraft. The fuselage again is elliptical
when viewed from the front, albeit now with its longer side in the vertical plane. This
design is fairly common when designing a conventional layout and has been used on
aircraft such as the Airbus A380-800. A second iteration of this design places the decks
in exactly the same fashion, however less vertical room is considered presenting a more
circular fuselage when viewed head-on.
The third and final configuration (Figure 2.3) is not dissimilar from the previous, again
placing one deck above the other. However, in this configuration, the lower deck is
significantly wider that the upper deck. When viewed head-on, the fuselage looks like
that of a single deck, but with a large bump above it that runs the length of the body [1].

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Wing Design
The design of the main wings or “main plane” is perhaps the most important aspect of
the project. The most drastic design changes for the benefit of the aerodynamic
characteristics of each model will be changes in wing position along the body and their
integration into the fuselage itself. Since there is insufficient time to go into the most
intricate design details, a typical aerofoil used for an aircraft of this size will be
standardized and used on all four models, albeit at different scales.
The reference or trapezoidal wing is the basic wing geometry (Figure 2.4) used to begin
the layout and the root of this extends into the fuselage, up to the aircraft centreline.
This means that as the body blending becomes more emphasized, the reference wing
geometry will become less accurate. It is common to sweep the leading edge of the
wing behind the Mach cone, however since the models in question will only be tested at
subsonic speeds; the position of such Mach cone is unknown. Instead, a suitable sweep
angle can be chosen either by standardizing it across all four models, or by basing it off
data for aircraft concepts that most accurately represent each model individually.
By constructing a wind tunnel, the Wright Brothers were able to conclude that a long,
thin wing (high aspect ratio) produced less drag for a specific lift than a short, thick
wing (low aspect ratio) (Figure 2.5). As the wing generates lift, the air below the wing
tends to escape around the edges in an attempt to equalise the pressures above and
below the wing (Figure 2.6). The majority of this air rotates around the wing tip,
reducing pressure difference and thus the lift generated, whilst also pushing down on
the tip, reducing its angle of attack. The reduction of lift is coupled with an increase of
drag and both can be countered by increasing the aspect ratio, or more specifically,
reducing the overall wingspan. The induced drag can also be reduced by creating wings

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with sharp cut-off edges which make it difficult for the air to travel around the tip
effectively.
Another method to reduce drag is the implementation of winglets (Figure 2.7). Winglets
are wing extensions that protrude almost vertically from the wing tips. They are
cambered such that a specific design speed, the induced drag vortices actually push the
winglets forwards, effectively creating negative drag. Winglets or “air fences” also
provide a barrier against escaping lower air, reducing the chance of pressure
equalisation over the wing [3].
Tailplane/Tail fin Design
Tail planes, or stabilators as they are sometimes referred to as, are small wings that are
symmetrical about their chord. There is no pressure difference between the upper and
lower surfaces and thus they produce no lift unless their angle of attack is altered. Their
sole purpose is to provide longitudinal stability, trim and to house the pitch control
surfaces. The tail fin extrudes vertically above the body of the aircraft on a conventional
layout. It provides transverse stability and must have the ability to deflect enough to
counter the yaw, should an engine failure occur on a multi-engine aircraft. The fin is
generally placed slightly forwards of the tailplane, in order to avoid any disruptive
airflow being deflected by the elevators. The tailplane and tail fin are often considered
together, as they will be in this section. There are multiple non-conventional
configurations that each serve their own purpose for the particular role that aircraft is
designed for.
The first of these non-conventional configurations is known as the “T-tail” (Figure 2.8).
This is almost identical to the conventional layout except that the tailplane is now on top

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of the tail fin, hence the “T” shape. This lifts the tailplane out of the wing and jet wash
making it more efficient and also reduces the tail fin size due to the endplate effect.
The second configuration is known as the “Cruciform” (Figure 2.9). As the name
suggest, the appearance is that of a cross and is due to the positioning of the tailplane
half-way up the tail fin. This configuration acts as a hybrid between the conventional
and T-tail layouts, providing all the benefits of the T-tail except the endplate effect,
whilst avoiding such a large weight penalty.
The “H-tail” (Figure 3.1) places two half-size tail fins on the wing tips of the tailplane
in order to position them out of disturbed air flow. The configuration may also be used
to place the rudders in the jet wash to provide a greater effect in the event of an engine
failure. The endplate effect is active again allowing for a smaller tailplane, which
counters the added weight of having two tail fins.
The “V-tail” (Figure 3.2) neglects the use of separate tail planes and tail fins. Using
Pythagoras’ theorem it can be seen that the hypotenuse of any triangle will always be
shorter than the sum of the two perpendicular sides that join it. This means that a V-tail
has a considerably reduced wetted area. This reduced wetted area thus reduces the skin
friction of the tail area as a whole. Unfortunately, in order to provide the same control
as the separate system, the V-tail must be increased in size to the equivalent surface
area. Despite this, aerodynamic benefits can still be reaped from the configuration due
to the reduced interference drag.
“Twin tails” (Figure 3.3) position the tail fins away from the aircraft centre line and is
most useful in situations where the tail may become shielded from the airflow during
high angles of attack. This improves the rudder effectiveness but also adds weight to the

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structure. Twin tails are uncommon on commercial aircraft as maximum
manoeuvrability is not a strict priority.
“Boom mounted tails” (Figure 3.4) are available in numerous configurations
themselves, however this design would not integrate well with a single fuselage
commercial aircraft configuration and it therefore seems unnecessary to discuss it
further. Likewise, the “Ring-tail” (Figure 3.5) concept attempts to provide all tail
contributions by utilising an aerofoil-sectioned ring, housing two vertical wings, two
horizontal wings and often a propeller. This design is far more common on light aircraft
with “pusher” propellers and is again unsuitable for a long-haul airliner [3].
Powerplant Design
The engine cowling design is not something that is particularly focused on in this
project, however there is a strong intention to include engines on each model in order to
simulate the most realistic aerodynamic characteristics. The engine position and design
for each model configuration will be appropriate for the level of aerodynamics that that
particular configuration intends to achieve. Likewise, each of the engines will remain
hollow since, realistically, they would be providing thrust as well as generating form
drag.
Certification
Certification revolves around the idea of safety, or more specifically in aviation, flight
safety. Flight safety can be split into three main contributory factors: Man, Environment
and Machine. It is clear when referring to airworthiness of aircraft that machine is the

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most significant aspect to focus on. Airworthiness is defined in the RAI-ENAC as the
“possession of the necessary requirements for flying in safe conditions, within
allowable limits.” In more common terms the definition refers to having an aircraft with
the ability to fly in a safe manner whilst in typical flight conditions. It is the job of
airworthiness authorities to prescribe airworthiness requirements and procedures,
inform the relevant parties of such prescriptions, control aeronautical material, design
and manufacturing and to certify aeronautical material and organisations. When
considering design, the authority must assess whether changes in the aircraft design are
minor or major. Minor changes include those that have negligible effect on mass,
balance, structural strength, reliability and operational characteristics such as noise and
emissions. Anything not included in the list above is considered a major change and
must be looked into further. In the event of a major design change, a new type
certificate must be issued. If the engines of an aircraft use different principles of
operation, such as changing between turboprops and jets, the aircraft is considered to
have had a major change, regardless of the remaining identical airframe, and must be
issued a new type certificate [4]. It is therefore easy to see that changing the entire
design of a long-range commercial aircraft would be a comparably huge task to certify
and any aspect of the airframe that could potentially be left unchanged would be of
great benefit to the manufacturer. “Alien” designs and technologies can cause huge
delays in the production of new aircraft, where new laws and legislations must be
constructed to deal with an aircraft that operates so differently. The certification
program may cover stability margins and evacuation times, as well as loading/off-
loading safety and general passenger comfort.

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Industry Examples
Today’s Aircraft-Boeing 787
A zero-lift induced drag breakdown of the 787 (Figure 3.6) shows that 37% is caused
by the wings and 39.2% by the fuselage and fairings. Even then, this only represents
52% of the drag that the aircraft experiences during flight. More so, the 787 is a
relatively new aircraft, with one of the lowest drag coefficients on the market today.
This shows that a significant amount of drag could be eliminated, given improved
integration of the fuselage and the wings [5]. Likewise, if the structure allowed,
integrating the fairings or “flap canoes” into the wings would also be highly,
aerodynamically beneficial.
The use of composite materials (Figure 3.7) has led to reduced structural mass, which in
turn allows for higher aspect ratio wings. As mentioned earlier, high aspect ratio wings
provide reduced drag during flight. The high aspect ratio is accompanied by raked
wingtips which make use of vortices and provide greater lift for a given volume of air
that would otherwise only be possible with a greater wingspan [6]. Other drag reduction
systems on the 787 include small pore in the leading edge of the tail fin and stabilators
that allows the passive flow of laminar air. While the concept appears to work, this fine
tuning gives the impression that there is little left to improve with the conventional
layout and that large leaps in performance must be achieved with all-new ideas.
Alternative layouts-Airbus 2050 Concept
A recent study by Airbus revealed that 96% of people worldwide think aircraft will
need to be more sustainable or “eco-efficient”, 86% think less fuel burn is the key,
while 85% think reduced carbon emissions is the answer and 66% desire quieter

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aircraft. Whilst not stretching to the extent of the blended-wing-body (BWB), the
Airbus 2050 Concept (Figure 3.8) aims to answer all of these requirements via a hybrid
between today’s conventional designs and the X-48 (see below). The aircraft certainly
isn’t one single form, however many of the major components are gently integrated into
each other, forming a far wider, wing-based design than aircraft such as the Boeing 787.
More specifically, the wings themselves are long and thin, whilst the fuselage is curved:
more bulbous towards the front before gently narrowing towards the main wings. The
engines are semi-embedded into the body forming the roots of the tailplane. The
tailplane itself is “U-shaped”, shielding the noise pollution from the rear of the engines
[7].
Body blending-Boeing/NASA X-48(B)
D.Kuchemann (The Aerodynamic Design of Aircraft, 1978) states that interference
effects are always largest at the junction between intersecting bodies [8]. Therefore, it
would make sense that reducing the quantity of intersecting bodies would thus reduce
the significance of interference effects. The full extent of eliminating the intersecting
bodies, is the blended-wing-body design.
Boeing and NASA have recently partnered in creating the X-48 blended-wing-body
(Figure 3.9); a potentially feasible replacement for current commercial aircraft.
Advantages of this aircraft design include: high fuel efficiency, low noise and a large
payload, relative to the aircraft size. Currently, the aircraft has flown only as a large RC
model, with tests at low subsonic speeds and low altitude. Such tests serve to prove that
the design is safe for commercial transport, whilst also allowing analysis to be
conducted on stall characteristics and engine-out handling qualities [9].

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A more recent development of the project, the X-48C, has proven that the blended wing
body design can in fact be operated safely and will produce a significant increase in fuel
efficiency as well as reduced noise. It may be noted however, that the X-48C is
considered as a hybrid-wing-body aircraft since design developments caused a more
conventional tailplane to be integrated into the design. The greatest difficulty has been
presented by evacuation regulations making the positioning of emergency exits a
challenging task. The aircraft has so far been tested at speeds of up to 140mph but both
Boeing and NASA intend to complete supersonic versions of the design [10].
Certification and Airworthiness-Beechcraft Starship
During the late 70’s, Beechcraft’s class leading King Air 90 twin prop had a market
share of around 50%. Amongst the remaining market share was Cessna, Mitsubishi,
Rockwell and Piper. Despite this, the design for the King Air was getting on for 15
years old and it was clear to Beechcraft at this point that the only way was down from
there on, unless the design made a dramatic leap forward. With this in mind, work
began on a brand new, pressurized, all-composite twin-engine, business turboprop,
using the latest technology and an innovative design. The design itself was that of a
canard, with rear facing “pusher” turboprops and large winglets to replace a centralised
tail-fin. The tail-fin itself was neglected due to position relative to the engines and
would have acted as a massive soundboard causing terrible passenger oral discomfort.
The use of an all-composite airframe was chosen as the new, larger cabin would have
otherwise added considerable weight to the aircraft.
The proof of concept Starship was completed in record time and proved to the world
that Beechcraft was very serious about implementing this radical new design.

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Unfortunately, the concept gave the public impression that Beechcraft was far further
ahead in the development phase than it actually was. In the eyes of the customer, the
design was ready and simply needed some small tweaks during the certification
program in order to pass the aircraft for mass production. The reality was that many of
the component subcontractors had failed to deliver on time if at all. Delays were
worsened as the company realized that development would be placed solely on
themselves. Further to this, the FAA insisted that Beechcraft install a stall warning
system, a serious challenge on an aircraft inherently designed not to stall. The FAA kept
a close eye on the Starships development since it would become the first FAA certified
composite aircraft. The certification board had no established design-life criteria for
composites and so a strict and rigorous test program was designed and implemented
subjecting a test structure to damage over 40,000 hours: two times the airframe lifespan.
One of the greatest certification barriers was lightning protection on the all-composite
body. Composite was found to be liable to being blown apart if hit by lightning and thus
the Starship required an underlay of thin metal wires to “earth” and distribute the
current safely. The aircraft made multiple flights during the 1980’s and received FAA
certification on 14th June 1987 – 8 years after the project began. Despite the $300
million investment in the project, only 53 Starships were built and only a fraction of that
were sold. The project had taken far longer than customers were prepared to wait and
ultimately Beechcraft lost its dominant market share [11].
The literature sourced above provided real scope for the design of the various aircraft in
this project, with many considerations involving design criteria, layouts available and
certification restrictions as well as their consequences.

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Initial Designs
The “Initial Designs” section focuses on all the concept art that was produced, before
the four main aircraft designs were finalised and chosen. Please refer to Appendix C for
this section.
Perhaps the most relaxed and least restricted part of the project, the initial design phase
involved the relatively laid-back process of getting some ideas down on paper. The
most logical starting point, was to design the two extremes.
The first design was to virtually replicate the geometry of the Airbus A380-800 (figure
1.1), as this would provide a base value for comparing the remaining three designs.
Next the process of making each successive design more blended was adopted. With the
original project dismissing the reconfigurable fuselage, the first four designs to be
mapped progressed in shape from that of a conventional “tubular” aircraft, to that of a
more elliptical silhouette. Knowing that the final extreme would not differ greatly in
shape from the Boeing X-48, the fourth concept blended the main wings and
considerably flat fuselage into one. All major extrusions were either removed, or
integrated into the mainframe, such that the design echoed that of a Manta Ray (figure
1.2).
With the two extremes in place, the gap for the remaining two concepts proved to be
potentially more challenging. While it was easy to see a half way mark between the
A380 and the “Manta Ray”, it was less easy to design two aircraft to fill the gap and
would still be different enough from one another for testing to be worthwhile. Since
development was still in a very early phase, the second concept (figure 1.3) adopted the
design of the A380, though with partially more extensive blending not dissimilar to the
Boeing 787 Dreamliner. Likewise, the third concept (figure 1.4) adopted more of the
“Manta Ray” design, though with a few elements borrowed from a more conventional

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layout. While, concepts two and three were not distinguished enough for testing at this
time, there was still plenty of opportunity for development and a sufficient foundation
had now been established.
Initial Fuselage Design
The “Initial Fuselage” section explains the processes and problems faced of designing
a fuselage shape that would best accommodate four vastly differing aircraft
configurations. This section deals with the design of the body itself as oppose to the
techniques used to make the body interchangeable, which will be explained in the “Re-
configurable Fuselage” section. Please refer to Appendix D for this section.
The shape of the fuselage played the important role of being the core for each design.
With the single-fuselage project now in consideration, the fuselage cross-section needed
to adapt to all four configurations. Ideally, its cross-section would be circular or
elliptical with its longer side in the vertical plane (figure 1.1), in order to best suit a
conventional layout. However, a substantially more “squashed” fuselage (figure 1.2) i.e.
Elliptical with its longer side in the horizontal plane, would be more suitable for a flying
wing layout. Clearly, it wasn’t possible to design a cross-section that would be perfect
for each of the four configurations, so it was necessary to create something that could
combine as many elements from both extremes as possible. Since all the aircraft in
question were to be designed with a full upper and lower deck, a circular cross-section
was chosen to achieve the best average for each design.
Next in question, would be the side profile of the fuselage. As mentioned in the initial
designs section, the fuselage originally progressed from a tubular to an elliptical
silhouette as the designs became more fluent. Since the fuselage was now shared, this
progression in design was no longer possible and thus an average for all the designs was

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once more required. The design of the side profile retained a fairly conventional shape,
though with a gently sweeping front fascia, such that the nose cone and cockpit housing
were blended into a single continuous gradient (figure 1.3). Succeeding this gentle
incline, a typical tubular body was chosen over the bloated elliptical body more suited
to the flying wing, since the linear sides would provide a far less complex fixing point
for the various wing shapes and positions.
Belly fairings, typical of almost every commercial aircraft currently on the market were
unfortunately not possible, since the fuselage was to accommodate both a conventional
and a Canard design. This would mean either the fairing would have to move with the
wings, a modelling problem that will be explained in the “reconfigurable fuselage”
section, or create an abnormally large fairing that would run almost the whole length of
the body (figure 1.4). The latter of the two options would cause the conventional layout
to have an awkwardly large fairing section, rear of the main wings, whilst the Canard
layout would have an adversely large fairing in front of the main wings. Since the large
fairings would be unrealistic for all configurations, it was deemed necessary to neglect
them entirely.
The rear of the fuselage again retained a fairly conventional design, albeit with the tail
section reducing in cross-section slightly earlier along the body than standard
convention (figure 1.5). The reason behind the particularly large tail decline was to
influence a side profile shape that would integrate a little better whilst the aircraft was in
its body-wing-blended (BWB) configuration. Ideally, for the BWB wings to be fully
integrated, the fuselage would have to narrow considerably, perhaps as early as the half-
way point, however this would have caused significant problems when designing and
integrating the more conventional layouts. For this reason, a perfect BWB fuselage was
sacrificed so that the remaining three models could be simulated more accurately.

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Finally, the tail tip was cropped subtly to simulate the exhaust outlet for an auxiliary
power unit (figure 1.6). This seems like an unnecessarily precise detail, though
nonetheless a feature shared by aircraft of all shapes and sizes. Since the modelling of
an APU outlet would hardly be a challenge, it was decided that such a feature was worth
including even if little difference was made to the results.
Solidworks
The “Solidworks” section describes the primary techniques that were learnt prior to
modelling the four concepts and how they were more effective than alternative
techniques available in the program. Please note that due to the nature of the program
the term “planes” refers to an axis based surface that allows for drawing and the term
“aircraft” will be used when referring to the designs themselves. Please refer to
Appendix E for this section.
When compared with programs such as Autodesk, Solidworks was a breath of fresh air
in terms of its procedures and architecture. The ability to easily sketch and extrude on
any surface without having to first lay down a sketch plane and dimensions on that
surface, saved a great deal of time and effort during the design phase.
The cylindrical shape of the fuselage meant that modelling could be achieved in one of
two ways. The first method though primitive, was almost instantaneous, simply
extruding a circular cross-section in the longitudinal axis. Succeeding this, the cylinder
would be either filleted or domed at either end, in order to establish a nose and tail
section (figure 1.1). The problem with this method was that the centre points of the
fillet/dome could not be repositioned meaning that both the side and plan profiles of the
extrusion were a long way off the desired body silhouette. It was therefore necessary to
use a more advanced method known as lofting. Lofting is a tool that uses two or more

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cross-sections to extrude a prism along a desired axis. It then uses a user-defined side
and upper profile to adapt the prism to the correct shape. Before using the tool, the
combination of cross-sections and profiles used mimics that of the desired model in
wire-basket form (figure 1.2). Should the resulting loft not quite meet a desired
standard, further cross-sections can be added to further define the prism’s parameters.
This method is so effective at creating complex shapes at ease, that it has been used to
create every part of the aircraft in this project. The engines in particular, were created in
an identical way to the fuselage due to their equally tubular shape.
Following the loft procedure used for the fuselage, the main wings, tail fin and
tailplane/canards could be modelled in an almost identical fashion. The outline of each
lifting surface was mapped leaving the root chord and tip chord open (figure 1.3). It was
essential for the corresponding points for the leading and trailing edges of the wing to
align with each other, such that the root and tip chords were parallel should they be
mapped. Following this, the desired aerofoil was mapped at the root and tip (figure 1.4),
perpendicular to the plane of which the wing edges had been mapped, thus creating the
“wire basket” that would complete the loft. The process was repeated for all lifting
surfaces.
In the event that certain aircraft designs required wing flex or gently swept winglets, the
main wings would be mapped so as to include this extra length (figure 1.5). The “flex”
tool would then be applied as necessary so that the wing or winglet could be literally
“bent” upwards. Should wing flex be desired, the limits of the flex tool would be
expanded to the root and tip chords so that the flex would apply to the entire wingspan
(figure 1.6). Should a winglet be desired, the limits of the flex tool would be positioned
such that they neighboured the winglet “hinge point” (figure 1.7). A secondary use for
the flex tool was that of wing twist and winglet camber. A common feature of many

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aircraft to improve roll stability during stall, the flex tool allowed for the wing to be
twisted in a torque based manner, such that the angle of incidence reduced from root to
tip. Likewise, the winglets that had already been “flexed” upwards, could be cambered
gently in the transverse axis to simulate their ability to counter wingtip vortices.
The final parts to model on each aircraft were the small details such as the flap
hydraulic fairings (figure 1.8). As the only parts not designed using the loft tool, the
fairings were applied by first setting up vertical planes stepped equally along the wing.
This was achieved using the reference geometry plane tool, which allows the user to
define a reference plane, the number of subsequent planes to make and the distance of
separation between each of these subsequent planes. With each of the necessary planes
now defined, the side profile of the fairings could be mapped. The outlines were then
extruded symmetrically about their corresponding planes and filleted longitudinally, to
achieve the most realistic shape. The engine pylons (figure 1.9) were created in an
identical manner to the fairings, with their corresponding reference planes laterally
centred on each engine.
With all parts modelled, the next step was to load a new Solidworks assembly. The
assembly section allowed separate part files to be accumulated into one space and to be
positioned as desired. More importantly, once a single wing had been added, the mirror
feature could be applied (figure 2.1). A reference mirror axis and all the parts the user
wishes to mirror on that axis, are selected. Once the process has completed, the mirrored
part and its original move as one, meaning that perfect symmetry can be achieved. As a
more specific example, should wing dihedral be desired, both the original and the
mirrored part can have their dihedral angle adjusted simultaneously, eliminating time
spent on ensuring precision. It was not uncommon at this stage to recognise that some
of the parts seemed incoherent with each other and a powerful combat for this was the

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ability to modify the individual part files, whilst still in the assembly. This was a very
useful feature, as it allowed the user to make the necessary modifications to a part,
whilst using its neighbouring parts as a reference.
Finally, the assembly feature in Solidworks could be used to showcase an exploding
view of the model in question (Figure 2.2). Likewise, if the model had strict
construction limits, the parts could literally be put together, to ensure an exact fit before
printing (figure 2.3). This will be explained further in the “Reconfigurable Fuselage”
section.
Concept 1
“Concept 1” describes and discusses the design ideas behind the first configuration and
how they were influenced by the Airbus A380. Please refer to Appendix F for this
section.
Concept 1 was the current extreme of the four designs. With a heavy influence from the
Airbus A380, the design had no unconventional features. The main wings were
positioned just forward of the fuselage half way mark, with a tailplane in its typical
location at the rear. A single tail fin protruded from the centre of the rear fuselage, just
ahead of the tailplane in an expected fashion.
During its development, Concept 1 lost the two outboard engines (figure 1.1), leaving
just the two inboard, since it was considered that as many of the features between each
configuration should remain constant and the other designs lacked four engines also.
Whilst continuing with the design, the outboard engines were reintroduced, as it was
decided that a quad engined configuration would most accurately simulate a long-haul
double decker aircraft using today’s technology. Though this now meant that the
engines had become a variable between the configurations, the model validity was

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retained by adjusting the engine geometry for the remaining three aircraft, as will be
explained respectively.
The main wings, were modelled using a plan outline and aerofoil data directly from the
A380, with no consideration of wing droop. The real A380 wing droops significantly
due to its excessive size and weight (figure 1.2), but then rises as the lift of the aircraft
increases. Concept 1 considered this rise as a permanent condition for the wings, since
the plastic used by the 3D printer was too brittle to realistically simulate this flex.
Nonetheless, the flex tool was applied to the inboard section of the wings, in order to
most accurately represent the shape of the A380’s wings when viewed from the front
(figure 1.3). Small air fences were modelled on the wing tips, since winglets would play
a key part in what was to distinguish the aerodynamics of each model. With this in
mind, the winglets were a little thicker in chord than desired, due to the precision
limitations of the 3D printer. Since the wing root belly fairing had to be neglected as
explained earlier, the main wings were required to pierce the body a little more so than
on the actual A380, as the joining area was now cylindrical instead of slab-sided (figure
1.4). This meant that some of the wing surface area was lost, as was some of the
wingspan, though both of these losses proved to be negligible in the grand scheme of
things.
The tailplane and fin of Concept 1 were modelled again off the A380, though aerofoil
data was unobtainable for these parts. Therefore, with prior knowledge that the tailplane
and fin of an aircraft are symmetrical about their chord, the upper cambered surface of
the main wings was mirrored and the result was deemed to be the most realistic
solution. It was imperative at this point that the dimensions for each of the lifting
surfaces were obtained, as this would become the base for designing the wings on each
successive configuration.

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The four engines to be used in the configuration were to be modelled next, a task that
involved obtaining a couple of extra dimensions from the A380. The original engine
parts included the shaping of the exhausts at the rear outlet (figure 1.5). Though at first
this seemed to simulate the engines in the most realistic manner, it was noted that the
engines for Concepts 3 and 4 were to be hollow. With the modelling of the engine
exhausts on Concept 1 and 2, this left a flat frontal area almost entirely blocking the
outlet. Realistically, the engines would be producing thrust as well as generating form
drag, it therefore seemed illogical that air could not pass through the engines so freely.
Because of this, the exhausts were removed, leaving just a hollow cowling that air could
pass through easily (figure 1.6). The only interference now within the engines, were the
pylons that intersected the cowlings for enhanced structural rigidity, though since the
pylons were of narrow nature they posed no threat to the validity of the model’s
aerodynamics.
With all the major parts for Concept 1 rendered, further attention was turned to the
smaller details. Four hydraulic fairings on each wing for the flaps were modelled and
this would become a standard on each of the remaining three aircraft also. The fairings
were sized similar to that of an A380, though due to the nature of the model, exact
dimensions for such small details were not necessary.
Concept 2
“Concept 2” discusses the progression in design from the first configuration and how
the changes made, though subtle, were significant enough to distinguish between the
two designs. Please refer to Appendix G for this section.

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Concept 2 was a relatively subtle progression in comparison to the remaining two
designs. The layout of the configuration was carried over entirely from the first concept,
though the distinguishing features were in the details.
The sweep angle of the main wings remained the same as its predecessor, however a
considerable degree of body blending had been added to the wing roots (figure 1.1).
This allowed for a more fluent transition between body and wing, a design feature that
was continued across the rest of the model aircraft. Likewise, the wing tips were far
more swept (figure 1.2) than those of Concept 1, with far less definition between the
end of the leading edge and the start of the wing tip. The air fences were removed
completely, replaced instead by a gently lifted wing tip area. The entirety of the wings
now were now polyhedral (figure 1.3), giving a parabolic sweep in the vertical plane to
simulate the wing flex of composite aircraft such as the Boeing 787.
The tailplane and fin shared the same body blending as the main wings and an equal
amount of sweep on their tips. Where surface area had been gained on the leading
edges, an attempt was made to reduce the trailing edges in order to remove surface area
by an equal amount. It was noted that due to the increased footprint of this blending on
the fuselage, there would be potentially more interference drag around the tail section,
as less area now separated the lifting surfaces. Likewise in reality, the extra material
required for the excessive blending would add weight to the structure as well as
increasing the skin friction drag coefficient.
Though the engines and fairings appeared to remain unchanged form Concept 1, very
subtle blending was applied to the areas where the engine pylons met the cowlings
(figure 1.4), to echo the rest of the aircraft. An attempt was made to replicate the
“toothed” engine outlet nacelles, as seen on the Trent 1000 and the concept art for

Page | 45
Concept 2 (figure 1.5). However, due to the complexity of modelling such an intricate
feature it was deemed unnecessary to spend considerable time on a design aspect that
would more than likely have no effect on the aircraft’s overall aerodynamics.
Concept 3
“Concept 3” describes and discusses the feasibility of a Canard design for commercial
aviation and explains the thought processes behind some of the unconventional design
features of the third configuration. Please refer to Appendix H for this section.
Concept 3 takes many of its design features from Concept 2 and presents them in a
drastically different layout. Most importantly, Concept 3 looks at the potential in
Canard configuration for commercial aviation, despite the complications that it can
bring.
Beginning with the front of the aircraft, two canard fore-planes identical to the tailplane
of Concept 2 protruded from the fuselage, just above the centreline. The positioning of
the Canards so close to the nose, not only gave an effective pitch moment arm between
the surfaces and the C of G (figure 1.1), but also allowed for a gently sweeping “S”
gradient from nose to wing tip (figure 1.2). Some consideration into the strength and
power of the actuators required to operate the Canards must be taken however, since an
all-moving surface of this size would take a substantial amount of hydraulic pressure to
move, during high subsonic airflow. This is not currently a problem for a conventional
aircraft of this size, since conventional tail planes are not typically all-moving.
Likewise, even when the entire surface does move during pitch trim, the alteration in
angle of attack is comparably tiny compared with that required by the elevators. Of
course, an all moving canard would not be required to deflect to the extent of a pair of
elevators. Nonetheless a great deal of force would be required, especially when

Page | 46
considering that many Canard aircraft require continuous adjustment of their control
surfaces by computer–based systems, in order to remain stable. Whether or not the
Canards would provide pitch and roll control or just pitch control, would have to be
examined further in a study of aircraft stability.
Moving rear of the Canards, a pair of fairly conventional main wings were situated,
slightly below the longitudinal centreline so as to remain out of the wash from the fore-
planes. The level of wing-body blending at the wing roots was not dissimilar to that of
Concept 2, since Concept 3 focused on the change in layout more than detail design.
The extent of blending was nonetheless slightly exaggerated over that of its predecessor,
so as to bridge the gap between the conventional and flying wing designs more
thoroughly. Like the previous two concepts, a typical aerofoil used by the A380 was
retained, since the wing cross-section was one of the most significant control variables
for the model. Four hydraulic fairings per wing were once again used, as it was decided
that despite the increased wing thickness over the previous two concepts, realistically
there would still be insufficient space within the wing structure to store the necessary
flap mechanics.
Probably the most noticeable feature of Concept 3 was the lack of a tail fin. The loss of
such a gargantuan extrusion from the fuselage could potentially reduce the form drag
coefficient massively, though at the cost of yaw stability. Since stability is such a key
safety factor in the commercial aviation industry, it would be unacceptable to neglect a
vertical control surface altogether. The loss of the tail fin was therefore compensated by
two over-sized winglets on the tip of the main wings. Because of the endplate effect, the
surface area of each winglet could afford to be less than half the size of the original tail
fin, reducing the overall skin friction drag. Also, the large winglets could provide yaw
stability and control, whilst also generating “negative drag” from the wing tip vortices.

Page | 47
The other significant change made to the aircraft was the engine geometry. Unlike the
engines pods typically hung below the wings of a conventional aircraft design, the
engines on Concept 3 were heavily inspired by that of the Airbus 2050 concept. The
pylons were completely neglected and instead the engine cowlings were moulded into
the wing structure. The engine intakes were still situated below the wings in order to
reduce sound pollution in the cabin, but the exhausts required a significant raise in order
to achieve an acceptable ground clearance on take-off and landing (figure 1.3). This
lead to a rather alien “milk bottle” side profile that would mean the mechanics of the
engine would have to be situated such that they finished before the raised section of the
cowling (figure 1.4). Otherwise, the main shaft of the engine would have to be
constructed at an angle (figure 1.5), which could cause a significant amount of shearing
force and thus lifespan complications. Another point to add would be that the lack of
separation between the lower wing surface and the engine air intake, could cause the
potential ingestion of the wing boundary layer into the engine. Whilst this was not
desirable, the engines on the model were simply representations and such a specific
design criteria could be overlooked. The engines themselves were placed particularly
far back along the body in order to pull as much of the weight and thus the C of G
towards the rear. This would mean the landing gear could be positioned further back
and hence the likelihood of a tail-strike could be reduced. Earlier designs for Concept 3
(figure 1.6) included a third engine situated where the tail fin would have been on the
fuselage, in order to further bridge the gap between the quad-engined conventions and
the dual-engined flying wing. However, it was not possible to include this third engine,
without widening the tail section of the fuselage. Since the fuselage was now shared
between the four designs and none of the remaining aircraft required a third, centrally
mounted engine, it was deemed best to neglect it completely.

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Concept 4
“Concept 4” discusses the “flying wing” extreme of the project and how it progresses
from concept 3 in order to align the designs, whilst still retaining distinguishing
features. Please refer to Appendix I for this section.
Concept 4 was the final extreme of the four aircraft, attempting to eradicate all
unnecessary extrusions and integrate them into one continuous shape. Since the aircraft
only had one main feature - the wings, it was essential that particular attention was paid
to the details and ensure that every part that had been eliminated from the previous
configurations, had been appropriately compensated for.
The design started its life as the “Manta Ray” aircraft mentioned earlier. The idea
behind the interchangeable fuselage had not been discussed at this time, so the fuselage
of the aircraft bared a very elliptical shape that was almost indistinguishable from the
wings. The body was virtually an aerofoil in itself and could have potentially generated
lift, meaning that the whole aircraft surface could be considered one giant wing.
However, with the introduction of a common fuselage that was less than ideal for this
aircraft type, it was necessary to adapt the wings to echo as much of the “Manta Ray” as
possible. The plan of the main wings began by using the simple trapezoidal geometry
based off the wings from Concept 1. The geometry was situated towards the rear of the
fuselage as this would represent the maximum extent of the wingspan. A smooth “S”
shaped gradient was then applied from the nose of the aircraft to the wing geometry
tips, to integrate as much of the wings into the body as possible (figure 1.1). An equally
smooth gradient for the trailing wing edge was then applied, to connect the wing tip to
what little of the fuselage remained behind the wings. This lead to a silhouette for the
main wings that boasted a huge amount of wing-body blending, whilst retaining a

Page | 49
notable and linear sweep angle for simpler calculations. The aerofoil used for the main
wings was again identical to that of the remaining three concepts, though with a small
raised lip, running the length of the trailing edge, to act as an effective tailplane (figure
1.2). Despite the vastly increased chord thickness at its peak, the shape of the chosen
aerofoil meant that the wings thinned dramatically towards the trailing edge. This
unfortunately meant that there would still be insufficient room within the wing
structure, to store the flap hydraulics/mechanics and so four fairings were once more
applied.
Like that of Concept 3, Concept 4 noticeably lacked a tail fin and this was compensated
by a significant amount of vertical wing sweep towards the tips of the main wings
(figure 1.3). Unlike Concept 3, whose fin compensating winglets were distinguishable
from the main wing surfaces, Concept 4’s sweep integrated the horizontal and vertical
surfaces into a single continuation. For a given wingspan, this increased the relative
surface area of the wings even more, thus improving the lift coefficient whilst retaining
some yaw stability. It must be noted that the area of the wing tips designed to
compensate for the tail fin on Concept 4, is considerably bigger than that of the winglets
on Concept 3, whose purpose is also to compensate for the lack of a tailfin. This is for
two primary reasons. The first is that much of Concept 4’s wing tips remain mainly in
the horizontal plane, so contribute far less to the transverse stability of the aircraft than
Concept 3’s winglets, which are almost fully vertical. The second reason refers to a
point mentioned in “Concept 3” to do with the endplate effect. The endplate effect
allows for two neighbouring perpendicular surfaces to be reduced in size, whilst still
providing the same effect as two larger, separate surfaces. The horizontal and vertical
surfaces of Concept 4 are so gradually integrated, the endplate effect would be

Page | 50
considered negligible and thus they must remain larger than the winglets from the
aircraft’s predecessor.
The engines used for Concept 4 remain identical to those of Concept 3, to act as a
control variable when compared against the first two concepts, who also share engines.
A point worth mentioning is that due to the increased surface area of the wing structure,
it is likely that the C of G of this aircraft would be even further rearward than that of the
Canard configuration. This means the landing gear would also be situated further back,
thus reducing the risk of tail-strike even more so. Perhaps the biggest safety risk to
threaten this configuration, is the auditorium style layout that would be necessary to use
the cabin space most efficiently. Whereas the remaining three aircraft have retained the
more tubular like structure, the flying wing would have a far more widespread seating
arrangement. As mentioned in the “Span Loader” section of the literature review, this
could cause a potential safety risk when evacuating the aircraft, as it could take
significantly longer to travel from the centre aisles to the emergency exits than in a
conventional aircraft.
The Reconfigurable Fuselage
The “Reconfigurable Fuselage” section explains how a fuselage that could
accommodate the four vastly differing configurations was designed and the concepts
behind the interchangeable sections for future use. Please refer to Appendix J for this
section.
As the heart of the new project, the ability to reconfigure the fuselage so as to
accommodate all four aircraft and a number of potential future designs, was an essential
part of the design process.

Page | 51
To begin, a slot was required towards the nose and towards the tail end of the aircraft, as
both a conventional tailplane and a Canard design were to be used. Typically the slot
size would be as small as possible, similar to that of an Airfix kit, since it would
normally only be used for guidance and support. However, since the model was
interchangeable, filler blocks would be required to close the gaps when each respective
configuration did not require wings to accommodate that location. In order to remove
and apply the filler blocks easily, the slots would have to be of sufficient size. Ideally,
the slots would run the perimeter of the body so that future configurations would allow
for placing the Tailplane/Canards at any height (figure 1.1). However, the purpose of
making the fuselage interchangeable was to utilise as much of a common body as
possible and so removing such a large amount of material would have been
contradictory as well structurally illogical.
The slot for the main wings was originally considered as a total removal of the lower
section of the fuselage (figure 1.2). This elongated section would allow for the forward-
based conventional main wings and the rearward-base Canard main wings to be applied
to the same slot consecutively. Problems arose when considering the mounting of the
model in the wind tunnel. With the mounting brackets situated at the centre of the
fuselage, the wing/fuselage slot section would be held perfectly in place, while the rest
of the aircraft would simply drop off due to gravity. Likewise, should the model for
some reason be mounted the correct way round, the main body would be held in place
while the lower fuselage/wing slot section would again drop off. Clearly the slot for the
main wings, like the tailplane/canard fore-planes, would have to be set within the
fuselage structure itself. The slot could remain well below the longitudinal centre line,
so long as there was sufficient material below the slot to support it. The area of the slot
not filled by wing for each respective design, would be closed by a filler block that

Page | 52
would be modelled behind/in front of the corresponding wing piece (figure 1.3). At this
point, the idea of modelling the belly fairings onto the each wing piece was considered,
however once the fuselage was cut from the model the resulting belly fairings would
have been too thin for the 3D printer to construct effectively. For this reason, the
fairings were neglected altogether.
The last slot to model, was that for the tail fin. This posed a problem also, since the slot
required by the tailfin would potentially pierce directly through the slot made for the
tailplane (figure 1.4). Not only would this cause a structural weakness in the tail area, it
would also mean that the tailfin or tailplane slots would have to be excessively short to
avoid colliding with one another. Thankfully, the problem was solved, thanks to the fact
that the tail fin slot could be offset considerably, so long as at least some of the slot
overlapped the underside of the fin (figure 1.5). For this reason, the slot opening on the
fuselage could be situated far further forward; ahead of the tailplane slot, strengthening
the structure and avoiding intersection complications (figure 1.6).
The wind tunnel mounting brackets raised concern due to their typical location on the
wings. While this would usually pose no threat to the model, problems arose when
considering the distance between the brackets and the stringer. Since the wings were not
in a permanently fixed location on the body, the distance between the brackets and the
stringer would constantly change. Despite the stringer having the ability to move freely
to some extent, the problem raised complications as to where the stringer mounting
should be located on the tail. The solution was to use an alternative single bracket that
would be mounted in the centre of the body. The bracket would be twice as thick as
each wing bracket to compensate for the lack of bracket quantity and the fixed location
on the body meant that movement of the main wings had no effect on the
bracket/stringer separation.

Page | 53
A final note was added that despite the exact fit of the parts, continuous configuration
changes would eventually cause certain features to become loose. Likewise, the tail fin
needed something to secure it in place, since the model was to be hung upside down in
the wind tunnel. For this reason, narrow cylindrical tunnels were modelled through the
fuselage, so that locking pins could pierce through the body and each wing part, once it
was in place (figure 1.7). This would hold the model together far more substantially,
especially during testing and would ensure that even loose parts would not detach in an
airflow. Upon reconfiguration, the locking pins could be removed using a thin metal
dowel, leaving each part to be pulled out as before.
With the design for the re-configurable fuselage in place, all of the parts to be applied to
the model were collated into one assembly. Using the cut extrude tool, slot openings
were cut into the fuselage, overlapping each respective fin/wing. The slot openings were
then used to cut the slots themselves for each of the parts, meaning the slots were
identical to their respective openings. The parts were then sectioned even further, so that
they were a suitable size for printing (figure 1.8) and smaller slots were cut so that the
permanently joined sections could be aligned later in the construction phase (figure 1.9).
To ensure that no errors had been made in this part of the modelling process, a further
assembly was made for each configuration and the models were “virtually” constructed
in Solidworks. This method highlighted any misalignments or irregularities that needed
eradicating, before the parts were to be printed.

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Construction Phase
The “Construction Phase” section explains the adjustments that were required once the
parts had been 3D printed and any amendments that were made to the model in order to
achieve aerodynamics testing standard. Please refer to Appendix K for this section.
With the model designs complete, a 430 hour printing time lay ahead. With the
introduction of a common fuselage a significant amount of material had been saved,
reducing the project cost down to £1997. Unfortunately, use of the printer was not
solely available for this project, as other dissertations also required its use. This lead to a
total build time of around 4-5 weeks.
As each part was printed, a certain amount of filler material was required as a support
for non-vertical surfaces (figure 1.1). This filler material was removed once the printing
process had been completed, using a pair of pliers. Ideally, the filler material would
have been soluble, meaning that each part could be placed in a bucket of water and the
filler material would simply dissolve. This would have reduced the physical workload
massively, since removing the filler in a dry manner proved to be a laborious and
sometimes challenging process. Removing the filler manually also proved to be quite
risky, especially on the later models that contained multiple brittle features.
The next area to evaluate, was the surface finish of each part. Though little could be
done to improve the printing quality, it was essential that each part was checked for
abnormalities that may have been missed in Solidworks, or had simply formed due to
insufficient placement of filler material by the printer. Should either of the two
situations occur, it was imperative that no time or material was wasted on printing
defective parts. Thankfully, no such defect occurred. The surface quality was perhaps at
its worst on the winglets of Concept 3 (figure 1.2) and the swept tips of Concept 4. Due
to the layered nature of the 3D printer, the models were orientated so that the striations

Page | 55
aligned with the direction of airflow if possible. Unfortunately, where one part
contained geometry on more than one plane, it simply wasn’t possible to align the layers
in the flow direction on both planes simultaneously. Since the winglets/wing tips were
the smaller of the two areas, it was deemed necessary to sacrifice their surface quality
for the benefit of the main wing sections.
With all the parts for each configuration printed and all filler material removed, the
parts that were to be permanently joined were to be glued together over night. In order
to ensure that the parts were correctly aligned, thin strips of aluminium were cut and
placed in the alignment slots that had been modelled in Solidworks. Correct part
alignment was essential, as any irregularities could invalid results during aerodynamics
testing.
At this point, construction had been virtually completed. The final stage was to sand the
slots; many of the parts had a very tight fit and changing them proved to be initially
quite challenging. Likewise, it was now possible to sand the surface area of each part to
improve the finish on the model. Due to time constraints, improvements to the surface
finish were not completed to their greatest extent, however since the project adapted to
focus on the model design instead of aerodynamics testing, the model finish can be
improved for a different aerodynamics based project at a later date.
Model Evaluation
The “Model Evaluation” section discusses the model limitations and expectations, as
well as the relevance behind 3D printing for the project. It also concludes and reviews
the project as a whole. Please refer to Appendix L for project achievements.
The project as a whole was a great success. Though no testing was achieved in the end,
the resulting models proved to be of a very high quality. After a final discussion with

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