Group Project Final

AVIA 1000 – Group Project ‘Boeing 737-800’
Group participants:
Ikram Benferchiche
Aous Awida
Peter
Zulk
Joshua Colton
Jonny Bentley
Due Date: 21st January 2016
AVIA 1000 – Technical Skills and Applications
Module Leader: Cllr Clive Hudson
Group advisor: Dr Darron Dixon-Hardy

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Executive Summary: (198)
The report contains an overview of the Boeing 737 and will be discussed in detail throughout,
beginning with the history and generation of the aircraft, moving onto one specific version of
the 737; the -800. The design configuration, design concept and main features that determine
performance were discussed.
Ethical issues associated with the -800 are also reviewed. Problems such as how the 737 was
effected by a faultily designed rudder, which lead to many fatal incidents, as well as how the
aircraft affects noise pollution and the global climate.
Further along the report, certain aspects of the -800 are reviewed and discussed. These aspects
were as followed:
 Mass & Centre of gravity
 Engines
 Undercarriage
 Fuselage
 Wings
 Tail
Simulation of the Boeing 737-800 are also conducted on the Merlin simulator. Many aspects
are altered in different methods and then simulated to produce results which are observed and
analysed.
It was concluded that the dihedral angel of the wings is ideal at 6⁰ and cannot be altered to
improve the aircraft. The wing sweep angel of 25.02⁰ is good enough for the operation of the
aircraft, though if higher speeds are required then an increase in sweep should be considered.

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Table of Contents
Executive Summary:..................................................................................................................1
1. Introduction: (Group work) ................................................................................................3
2. Overall Design of the Aircraft: (Group work)....................................................................4
3. Ethical issues associated with the aircraft: (Group work) ..................................................7
4. Mass, Centre of Gravity, Construction and Materials: by Ikram Benferchiche .................9
5. Engines: by Aous Awida ..................................................................................................13
6. Fuselage: Petar Bukureshtliev ..........................................................................................16
7. Undercarriage: by Zulquarnain Ayub...............................................................................21
8. Wings: by Joshua Colton..................................................................................................25
9. Tail: by Jonny Bentley......................................................................................................30
10. Conclusion: (Group work) .................................................................................................35
11. Acknoweldgments: (Group Work) ....................................................................................36
12. References:.......................................................................................................................36
13. Appendix:...........................................................................................................................38

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1. Introduction: (276)
The objectives of the group project were to be introduced to the basic principles of aircraft
design and to research the design features of the Boeing 737. There are six sections of the
aircraft to study in detail and nine aspects (Mass, Centre of gravity, Construction, Materials,
Engine, Fuselage, Undercarriage, Wings and Tail). Considerations were made on the effects of
changing these aspects on the performance of the aircraft. The changes that were decided on
for each aspect of the aircraft would be examined using the Merlin Engineering Flight
Simulator. Small changes were made to see if the aircrafts performance would improve or not.
The aims of this project were to widen the knowledge on how commercial aircrafts operated.
Completing this project would give an insight for future projects that can be given in the final
year and what will be expected of students.
The design, construction and function of each aspect of the Boeing 737 were found through the
research made during this project. By doing so, this has widened the knowledge on Aviation
Technology and how each aspect interconnects with one another for the aircraft to function to
the best of its ability. The use of the Merlin Engineering Flight Simulator gave an overview to
flight simulation. It also gave insight on what is to be expected when using the simulator again
in future if undertaking another project.
The figure below demonstrates the route map of the project. It represents all the task that were
taken and it also illustrates the duration that has been set to each task to be completed.
Figure 1: Gantt chart representing a Route Map for the Group Project.
9/12 14/12 19/12 24/12 29/12 3/1 8/1 13/1 18/1
Intro to the project
First meeting with supervisor
Complete the individual sections
Meeting with supervisor and Sim session
Group meeting (Ethics)
Analyse Sim Data
Group meeting (design and intro sections)
Group meeting (finish the project)
Practice presentation
finnal presentation

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2. Overall Design of the Aircraft: (1597)
Design concept:
The design process is a long and variant journey; as the process continues, certain aspects will
always be improved or removed, and/or new components may be implemented. To minimise
every possibility of these altercations, a robust design concept must first be created. Therefore
the design concept of the Boeing 737 was simple: the main purpose of this aircraft would be to
conduct many short-haul flights all across the world and to carry as many passengers as
possible while maintaining efficiency. The reason for the production of this aircraft was that
Boeing wanted a superior short-haul jet to compete with the Caravelle, DC-9 and the BAC
One-Eleven [1]. In November 1964, designers Joseph Sutter and Jack Steiner began work on
the 737. The original specification in 1964 for the 737 was that the aircraft was to hold a
capacity of about 60-85 passengers, an operating range of approximately 100 to 1000 miles
while also having 35% load factor [1]. However, the final design conception discussions
between Boeing and their launch customer Lufthansa, the capacity was increased to 100,
however the range and load factor statistics remained the same.
One huge design concept that allowed the 737 to shine among its competitors was due to
designer Joe Sutter who decided to mount the engines hard against the underside of the wing
instead of having them mounting them away from the wing on struts [2]. These wing mounted
engines produced many advantages, such as reduced interference drag, a better centre of gravity
position, quieter cabin, increased cabin space in the rear, an easier access to engines for
maintenance and meant that less pipework for fuel and bleeds was required.
In a general summarisation, the final wing-mounted engine design coupled with a new
fuselage-mounted horizontal stabiliser had an overall weight saving of 700Kgs over previous
designs as well as producing performance advantages.
History of the Boeing 737:
On 17th January 1967, the first 737-100 was introduced to the world inside the Thompson site
with Lufthansa being the principle customer, and was known as “the square”, due to it being
wide and long [2]. Later on, in 1988, United Airlines received the first delivery of the Boeing
737-200 [2], with a higher fuel capacity and more powerful engines [3].
1991 saw production of the models -300/-400/-500. Two years later, the orders of the 737
reached 3,100 and Boeing was developing the next generation model. Boeing 737-800 was
then launched in 1994 and made its first flight in 1998 [2].
The main change between each generation of 737 is the size of the wing. Most notably between
the Classics (-300, -400, -500) and the 'Next Generation' (-600, -700, -800, & -900). The
wingspan increased from 28.88m to 34.32m. The gross area of the wings also increased from
105.40m2 to 124.58m2 [4]. This is marginally longer and larger than its main competitor the
A320 which has a wing span of 34.09m and an area of 122.6m2 [5].

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The Boeing 737 is also produced in cargo variants which offer a larger capacity for the
transportation of goods than the passenger variants. The current variants in service are the 737-
300SF, 400SF, 700C and 800BCF [6], though none of these offer as great a capacity as the
larger aircraft such as the 747-8F.
The Boeing 737-100 originally began with the Pratt & Whitney JT8D-1 turbofan engine,
however just before the order was confirmed the JT8D-7 was commonly used by the 727. The
-7 was developed so that it could produce the same thrust of 14,000lb.st, however would be
able to perform at higher ambient temperatures than the -1, and for this reason the JT8D-7 was
chosen to be the standard power plant for the 737-100 and when approaching the end of the -
200 production the JT8D-17R was able to produce 17,400lb.st of thrust [1].
The solitary power plant for all 737’s after the -200 is the CFM-56, this was an improvement
of the previously used Pratt & Whitney JT8D-17R as it immediately produced 1,500 lb.st of
thrust more. Issues were found when attaching the engine to the wings of the -300 as its size
was a restriction in regards to ground clearance, this was resolved by flattening the nacelle
bottom and intake lip as well as moving the engines forward and raising them so that they were
level with the upper surface of the wing [1]. The engines were also tilted 5 degrees up allowing
there to be not only ground clearance, however also a enabling the exhausts to be directed
downwards reducing the effects of pylon overheating while also producing vectored thrust to
assist take-off performance. The fir CFM56-3 demonstrated to be almost 20% more efficient
than the JT8D. The structure of the turbine itself and the materials used to create it allowed for
an 8% fuel reduction and a 15% maintenance cost reduction allowing for a superior engine
performance [1].
Key Features of the Boeing 737-800:
The 800 (known as the 737-400X Stretch before its official launch as the 800 [7]) is one of the
strongest selling of the 737 family due to it having a new fuselage length which made it a more
comfortable plane than previous models.
The 737-800 is a particularly environmentally friendly aircraft with many significant features,
for example:
 The 800 has been improved with winglets; these help to reduce the aerodynamic drag
and fuel consumption by 7% [2].
 More thrust can be produced, while noise levels are below average [2].
 It can fly faster, higher and further. This is due to the improvements that have been
made to it, which are: increasing the wing area by 25%, extending the fuel capacity by
30% and the aerodynamic efficiency by 22% [2].
 The use of two fuel efficient and low noise CFM56-7 engines, which allow it to fly at
a cruise speed of Mach 0.785 at ranges of over 3,000 nautical miles [2].
 “Engine technology improvements, blended winglets and carbon brakes are among the
enhancements that reduce maintenance and improve the environmental performance”
[8].

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Figure 2: Schematics for the Boeing 737-800 showing dimensions in plan, side and
forward view [9].
Figure 3: Graph shows how the advanced wing design helped to improve the efficiency
of the 737-800 [8].
Airworthiness Codes:
The airworthiness codes contained in CS-25 apply to larger aircrafts. This is the category that
the Boeing 737 falls under. An example of this is section 25.613: Materials. It groups materials
in the aircraft into two main sections. The first section is where loads are applied through a
single member within assembly, failure of which would result in loss of structural integrity.
The other group is where this is not the case. Instead, the applied load safely distributes to other
load carrying members [10].

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The airworthiness code states that the first group of materials must have a 99% probability of
not failing and a 95% confidence about this. The second group must have a 95% probability of
not failing and again, a 95% confidence about this.
There are also many codes in place for the power plant of large aircrafts like the 737 in Section
E of the document. These range from obvious things like the power plants need to be able to
create propulsion to things like needing to be able to be access the inside of the engine for
necessary inspection and maintenance. The electrical components of the power plant must also
have an electric connection to the rest of the aircraft [11]. A very important specification that
must be met is each engine must be operable separately in at least one configuration. This is so
that if the failure of one engine arises in flight, power can be cut from it and flight can be
maintained [12].
These are only a few examples from tens of thousands but the point is that the designers of the
737 aircrafts had to follow these very specific guidelines along with thousands of others for
every aspect of the design.
Simulator Performance:
In order to learn more about, and potentially improve, the design of the Boeing 737, a model
of the aircraft was flown in a Merlin simulator whilst data about the flight was recorded. Certain
parameters were changed to see how they affected flight performance so that the design choices
of the aircraft could be better understood. The model was initially flown through a take-off and
cruise in order to provide a standard set of data for comparison, then further test were conducted
specific to each component to learn about their properties.
Overall, many aspects of the simulator model were accurate to the actual aircraft. For example,
during the first test flight, the data collected gave the largest thrust value from the engines to
be approximately 20534lbs, which lies between CFM’s published thrust range of 18,500lbs -
27,300lbs (CFM Aero Engines website). Furthermore, the basic dimensions such as wingspan,
length and height that were entered into the simulator model matched those values published
on the Boeing 737 technical website [1].
However, several problems were encountered whilst flying the aircraft as well as some
discrepancies in the model’s construction. Ontake-off, it was discovered that the aircraft’s nose
tended to dip down, causing the front wheel to oscillate in a caster effect and send the aircraft
off the runway. This was attributed to uneven force distribution with too much weight being
placed on the nose wheel, which is not a problem encountered on actual 737 aircraft. This
inaccuracy between the model and the real aircraft projects itself as an inaccuracy in the results
collected.
3. Ethical issues associated with the aircraft: (508)
Global Environmental Impact

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Millions of flights a year result in a large amount of carbon emissions, which takes its toll on
the Earth in the form of Climate Change. Climate Change will affect everyone. The aviation
industry is growing at a very fast rate and many parties need to make changes to create a
sustainable effect on the environment. One of the most important parties is aircraft
manufactures.
The Boeing Company has acknowledged that their fleet of aircrafts is going to grow at a very
fast rate and that it is their responsibility to maintain and improve the environmental impact of
their aircrafts. Boeing predicts a growth of traffic of 5% every year and for traffic to have
doubled in 20 years [13].
Boeing have spent a considerable amount of time and money trying to reduce the
environmental impact of its aircrafts. The original 737s were far less fuel efficient than the
737s of today. The 737 MAXs are 70% more fuel efficient than the 737 Originals [13]. Such a
reduction in fuel consumption has led to less carbon emissions. This has reduced the possible
effect of climate change that would have been present if these changes hadn’t been applied.
Local Environmental Impact
The turbofans engine equipped to the 737 are incredibly loud. This can cause discomfort and
irritation to residence near airports around the world.
Boeing have also implement many innovations towards reducing the sound pollution of its
aircrafts. Most of the new noise reducing
technology implemented into the 737-800
was a joint venture between American
Airlines and the FAA who funded the project.
Most notably, this added a feature to the rear
of the engine called the Variable Area Fan
Nozzle (VAFN) [14]. This can be seen in
Figure 1.
The VAFN is designed to improve fan
efficiency during take-off, climb and descent.
It does this by directed noise upwards away
from homes [15].
Safety
The safety record of the 737 has been almost immaculate in the 50 years of its operation. There
have been a total of 170 hull-lose accidents, resulting in the deaths of 4191 passengers and
crew [16]While this is relatively low, those are 4191 deaths that could have been avoided or
reduced with improved design of the aircraft.
A clear example of this is the 737 faulty rudder scandal of the 90s. Two major crashes in 1991
and 1994 have been faulted to malfunctioning rudders. Between these two crashes, 157 people
died. There were also 4 other rudder related failures in the 90s that ended in safe landings [16].
The FAA ordered a full rudder control system upgrade to all 737s by 2002 which has appeared
Figure 4: Variable Area Fan Nozzle
[15].

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to fix the problem. These lives could have been saved if the rudder control system wasn’t built
with this design flaw initially.
However, the Boeing Company has been striving to safer aircrafts. The original 737s had a hull
loss rate of 1.75 per million departures verses 0.54 for the classic series and 0.27 for the Next
Generation series [17].
4. Mass, Centre of Gravity, Construction and Materials: by Ikram Benferchiche (1144)
Mass:
The mass of the aircraft plays an important role in the performance of that aircraft, where
minimising the mass as much as possible will lead to better fuel efficiency and performance.
The Boeing 737 family has different masses depend on the model. The table below represents
a typical operating empty weight and maximum take-off weight of the 737 family.
Table 1: A typical operating empty weight and maximum take-off weight for different
models of the 737 Family [18].
Model 737-100 737-200 737-200
Advanced
737 Classic (-
300/-400/-500)
737 Next
Generation (-
600/-700/-800/-
900ER)
Operating
empty weight
(kg)
28,100 31,600 31,700 31,300 -33,600 36,400 -44,700
Maximum
take-off
weight (kg)
50,300 52,400 58,100 62,800 -68,000 65,500 -85,100
Centre of gravity (CG):
For an aircraft, the centre of gravity is the point of balance and its position is dependent on the
weight and position of all the parts of the plane and also the load the aircraft is carrying [19].
For a neutral stability the centre of gravity should be in front of the centre of pressure (CP). If
the CG moves forward of the CP, the aircraft’s nose will pitch down.
The manufacturer of the aircraft will place limits for the location of C of G on the ground and
during the flight, this is due to making sure that the plane is correctly controllable and stable.
The figure below illustrates an example of those limits and the position of both CG and CP.

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Figure 5: The position of CG and CP on an aircraft and their limits [20].
Construction:
There are approximately 367,000 parts on a 737 Next Generation, not all part are built by
Boeing, they are all from over the world for the purpose of saving time and money. For
example: Fuselage, engine nacelles and pylons were built in Wichita (US); Ailerons were built
in Malaysia, rudder from Belfast (Northern Ireland) and Inboard flaps from Japan [1].
Once the fuselage was joined with wings and the landing gear, it was moved down for the
engine, interiors and avionics. Once all was done, Boeing made tests on the systems and the
engine before making the flight to the Boeing field, where it was painted and all set to be
delivered to the customers. .
The next generation models have 33% less parts that the classic model, this has reduced the
time of production [21].
Materials:
[21] Listed the materials used for the Boeing 737, and also which part uses what material and
the reason for that usage. It was found that the fuselage of the Boeing 737 is a semi-monocoque
structure, the load is carried by the frames and stringers and partly by the skin. The fuselage is
made from aluminium alloys, however the following materials are used for different parts.
Fibreglass: tail cone, centre and outboard flap track fairings.
Kevlar: Engine fan cowls, inboard track fairing and nose gear doors.
Graphite/Epoxy: rudder, elevator, ailerons, spoilers, thrust reverser cowls and dorsal of
vertical stab.
Giving that the main material used is aluminium alloys, there are different types used for
different area. This is depending on what the characteristics and properties required for the part.

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Mainly, the alloys are of aluminium and zinc, magnesium or cooper. Below are some of the
alloys and what parts they are used for.
Aluminium alloy 2024: it is used for fuselage skin, slats and flaps. This alloys is used for these
parts as they are loaded in tension and by using that alloy the parts will have good fatigue
performance, high fracture toughness and slow propagation rate.
Aluminium alloy 7075: which is used for frames, stringers and wing ribs to give them high
mechanical properties and make them resistant to stress corrosion cracking.
Aluminium alloy 7175: it is used for landing gear beam to make it very tough and give it a
very high tensile strength too.
Aluminium alloy 7055: that alloy is used for wing lower skin, which lead to it being a good
superior stress corrosion.
Simulator data analysis:
The Merlin flight simulator was used to fly Boeing 737-800 in its actual conditions and then
experiments were done by changing some of the figures to see what impact would that have on
the aircraft performance and also maybe to try to improve the Merlin model.
The following experiments were carried in that section:
1. Normal take-off: take-off has been experienced where all technical figures on the
simulator were kept constant (they meet the standard Boeing 737-800 figures). Full fuel
and payload were used. Takeo-off wasn’t great due to slipping either to the right or to
the left and that was due to some problems to the model itself.
2. Take-off with 50% of fuel and payload: once the fuel and payload levels were put
down from full to 50%, the plane was able to take however the ground speed was
different from the normal take-off mentioned above. Less fuel means that the aircraft
will be lighter which therefore will lead to change in the position of centre of gravity.
3. Take-off with 10% of fuel and payload: with a very low level of fuel and payload,
the aircraft tended to take-off in a short time and also the distance of take-off was less
compared with the previous two.
The figure below illustrates the difference in terms of fuel percentage per unit time between
the above three take-off’s with different initial fuel/payload state.

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Figure 6: Rate of burned fuel per second.
4. Take-off / moving CG backwards by 0.5 m: when moving the centre of gravity
toward the position of the landing gear, the nose of the aircraft pitched up. This means
that the aircraft will have a higher cruising speed as the stabilizer deflection will
increase in order to balance the aircraft.
5. Take-off / moving CG forwards by 0.5 m: moving the centre of gravity far away from
the undercarriage involved pitching the nose down. As the CG moves forwards, stalling
will occur at a higher speed as the angle of attack will be reached at a higher speed and
this is because there are more loading on the wing. The forces needed to be applied on
the elevator tends to be higher too, this is due to the need of increasing stabiliser
deflection in order to balance the plane.
6. Take-off / moving CG backwards by 1 m: the aircraft became less stable when the
CG moved backward as the angle of attack increased.
Conclusion from the simulator data:
Changing the mass of the aircraft before take-off by decreasing the level of fuel and payload
resulted in a change in the rate of burn of fuel per seconds. Where less fuel was burned each
second. This also has an effect on the distance travelled before taking off, where less distance
occurred at a lower fuel level.
The centre of the gravity position influences the angle of attack of the wing, the force on the
tail and the degree of the stabilizer’s deflection needed to keep the aircraft in equilibrium.
y = -0.0163x + 100.07
y = -0.012x + 50.097
y = -0.0164x + 10.054
0
20
40
60
80
100
120
0 5 10 15 20 25 30 35 40 45 50
FuelState%
Time (s)
Take-off with full fuel and payload
Take-off with 50% fuel and payload
Take-off with 10% fuel and payload

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Forward CG results in a more stable aircraft that has faster Stall speed (higher Indicated
Airspeed) but a lower cruising speed. Backwards CG makes the aircraft less stable, have a
smaller Indicated Airspeed and the cruising speed will be higher.
5. Engines: (1191)
Generation of the 737 engine
The Boeing 737 is part of a long generation family, starting from the 737-100 and advancing
all the way to the 737 – 900. Throughout this aircraft, like any other commercial aircraft,
consists of many complex and imperative components ranging from the landing gear all the
way to the yoke in the cockpit, however one very vital component to the operation of an aircraft
is the engines. The engines provide certain pounds of thrust using a turbofan engine which is
one example of a gas turbine engine. Throughout the advancement of the 737 generation, the
maximum pounds of static thrust produced by these turbofan engines have increased
substantially as seen [22]. The original engine used for both the -100 and -200 were in fact the
Pratt & Whitney JT8D-7 which provided around a maximum of 14,000 lb.st. (Pounds of static
thrust), however this was then improved throughout the aircraft series until the -200 advanced
could produce 17,400 lb.st resulting in the JT8D-17R.
Figure 7: JT8D Cutaway [22].
After the generation of the -200 the sole power plant for all of the 737’s is the CFM-56. The
core of this particular engine is produced by General Electric with SNECMA producing the
fan, IP compressor, LP turbine, thrust reverses and all external accessories. A key issue with
this particular engine was that it was such a high bypass, meaning that it was physically large
which resulted in very little ground clearance, however this was overcome by mounting fittings
on the lower sides to flatten the bottom nacelle and intake lip. The CFM56 consisted of different
features to the JT8D as the engines were raised and moved forward so that it was level with the
upper surface of the wing and was also slanted 5 degrees up allowing for a better ground
clearance as well as directing the exhaust downwards which not only reduced some of the
effects of the pylon overheating, however it also gave some vectored thrust which assisted take-
off performance, this along with many other aspects proved that the CFM56 was almost 20%
more efficient than the JT8D [22]. The most recent and up to date series of this engine, the
CFM56-7B, consists of a 61 inch diameter solid titanium wide-chord fan with a new LP turbine

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turbomachinery, a new single material in the HP turbine, all of which produced an 8% fuel
reduction, and a 15% maintenance cost reduction.
There are significant improvements to the engine between the JT8D and the CFM56, one of
them being the noise levels produced. The original JT8D-9 engines used for the -100/-200,
produced around 75 decibels in noise, enough to disrupt passengers from normally conversing
with a noise contour that extended 12 miles, however since the introduction of the 737-700’s
CFM56-7B in 1997 the 75-decibel noise contour is reduced to 3.5 miles long.
Figure 8: CFM56-7B Jet Engine used in the (737-600/-700/-800/-900/-900ER) [23].
Data Collected
A lab practical was conducted on the Merlin simulator, where a series of tests were completed.
The Merlin simulator allows designs of certain types and hybrids to be simulated. These types
of designs can be:
 Single and Multi Engined Piston and Turbo Prop Aircraft
 Single and Multi Engined Jet and Turbo Fan Aircraft
 Gliders
 Fixed Wing V/STOL
 Rotary Wing Aircraft with up to four rotors – and Auto Gyros
These are a list of many more designs that can be simulated on the Merlin. A model of the
Boeing 737 was introduced into the database of the merlin, allowing for a range of tests and
data to be collected. Some of these tests included the change and manipulation of the CFM-56
engines on the 737.
The model of the Boeing 737-800 did contain an issue that did cause an impact to the simulation
experiments. The undercarriage of the aircraft, specifically the front nose gear, failed when
approaching 100 KIAS (Indicated air speed). The nose itself would collapse into the ground,

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lowering the nose which subsequently caused the aircraft to yaw greatly to the right or left.
This affected the way experiments were conducted as the pilot was forced to counteract the
failure by pulling back on the yoke without lifting before take-off speed. Due to this reason,
the results of each experiment were not as valid as intended because of the effect of the nose
failure.
Figure 9: Graph showing time against the indicated air speed during take-off. Aircraft
reaches take of speed at 26 seconds, 10 seconds faster than default aircraft.
The first aspect of the engine that was to be altered was the angle at which the exhausts exits.
The first experiment was running a normal take-off, however the angle pitch of both CFM-56
engines was set to 5 degrees above its default pitch. The effect of this was fairly minimal with
the only change in the indicated airspeed, when compared to an alike take-off with the default
angle of the Boeing 737 engines. The altitude pitch rate was smaller in comparison to the
default take-off, however this was due to the nose failure as the values were below ground level
meaning that the front nose gear did in fact lower into the ground requiring the pilot to
counteract the issue until take-off speed was reached, where the altitude pitch rate increased by
a larger amount than that of the default take-off. This is the result of the engine pitch changing
to an angle of 5 degrees. Another aspect of the data results that was observed was that the
aircraft reached take-off speed of about 150 KIAS, at a faster rate than that of the default take-
off.
The same experiment was repeated however, the pitch this time was a larger angle of 10 degrees
instead. When factoring in the effect of the undercarriage, the data received was slightly larger
with the nose lowering into the ground even more, thus subsequently meant that the pilot was
forced to counteract this issue even more than the previous experiment, however the pitch rate
was a slightly larger value with the pilot rotating at the same speed then previously. The pilot
added a comment of that the change of the angle to 10 degrees was in fact a smoother take-off
than that of both the angle of 5 degrees and the default take-off.
The next experiment was to move the position of the engine further forward on the wing,
moving from -11.65 m to -8 m. This produced results that were fairly similar to the previous
experiments in the sense as the nose failure still occurred, however the altitude pitch did not
differ from the previous experiments, although the indicated speed did increase for take-off
speed.
One more experiment was conducted with the position of the engine, however it was moved
further forward to -4 m along the wing. The results were again quite similar to the previous
0
50
100
150
200
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35
IAS(kn)
Time (s)Time IAS

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experiment with the altitude pitch rate still having a similar value, however the increase in take-
off speed was still consistent with the previous experiments.
Table 2: Table showing data comparison of the Indicated Air Speed and the Body Axis
Pitch Rate during take-off
Overall the experiments conducted on the Merlin simulator produced results did show certain
improvements to the performance of the aircraft, as take-off speed was reached at a quicker
rate. Not only this, however the pitch rate was also improved when the angle of the engine was
increased, however the result was invalid due to the major issue of the undercarriage on the
implanted model on the simulator.
6. Fuselage: (1186)
General knowledge
There are two main types for fuselage construction in use:
 Truss or framework type mainly used in light non-pressurized aircrafts.
 Monocoque or more widely used Semi-Monocoque which is in use for construction
of any other aircrafts. This type of use generally referred to stressed skin.

AVIA 1000. 2015/16. Boeing 737
17
The fuselage is the main and the biggest structure of the aircraft which is designed to carries
the aircraft payload i.e. the passengers or the freight as well as the flight crew. In addition it
offers an effective position to the flight crew for the aircraft operation, enough space for
controls, accessories and other equipment [24]. It spreads loads to and from main planes
(wings), tail planes, fin, and landing gear and in certain configuration, the power plant.
Pressurized Aircrafts
Structure must be capable of withstanding the axial and hoop stresses implemented by
pressurization forces.
Axial stress
Axial or also longitudinal stresses are formed in the fuselage of the aircraft when pressurized
and tend to elongate the fuselage.
Hoop stress
Hoop or radial stresses are produced in addition to the axial stress and tend to expand the
fuselage cross section area. The internal pressure produced by these stresses can be as high as
65,5 KN/m2 (9.5psi).
SEMI-MONOCOQUE CONSTRUCTION
With the increase of the aircraft size and the loads become greater the traditional monocoque
structure is not suitable. In this way additional members known as stringers and longerons
(Figure 11) are added to run lengthwise along the fuselage and joining different sections
together. The light alloy skin is then attached to the frames and stringers by riveting or adhesive
bonding [25]. The purpose of the stringers is to stiffen the skin and assist to sheet materials to
spread the loads equally along the entire length.

AVIA 1000. 2015/16. Boeing 737
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BOEING 737-800 Fuselage:
The Boeing 737-X program was launched on 29 June 1993. The new program substituted the
previous series. The 737-300X became the new 737-700 and the 737-400X became the new
737-800 (Figure 10). 737-800 was built significantly longer than its ancestor 737-400 at
fuselage length of 39.4m and seats up to 189. The fuselage diameter is 3,76m and max cabin
width is 3,53m. The maximum take-off weight of 737-800 version is 78,960kg. The maximum
structural payload which the aircraft can support is 21,319kg. The max cargo volume which
can be suited in the lower deck is 44.1 cubic meters [28]. The fuselage has semi-monocoque
structure. The loads are carried partly by frames and stringers and partly by the skin. In Boeing
Figure 10: Boeing 737-800 Fuselage [26]. Figure 11: Semi-Monocoque structure [27].

AVIA 1000. 2015/16. Boeing 737
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737-800 fuselage design, the designer reinforce where there are going to be apertures for
windows, doors as well as hatches. Primarily the purpose of this reinforcing in form of a frame
around the aperture, is to absorb the exerted loads that would have been carried by the skin that
has been cut away. The fuselage frames are stiffened together in order to transfer and share
loads and act to prevent cracks and propagation. The manufacture uses various different
aluminum alloys except for the following sections. Fiberglass is used for radome, tail cone as
well as center and outboard flap track fairings. Kevlar is used for engine fan cowls, inboard
track fairing and nose gear doors [21]. Epoxy and graphite can be found in the rudder, elevators,
ailerons, spoilers as well as thrust reverse cows and dorsal of vertical stab. The alloys used for
fuselage constructer are mainly of aluminum and zinc, magnesium or copper. The different
alloys are mixed with different ingredients to give different properties for specific purpose.
Fuselage, skin, flaps and stabilizer area primarily loaded in tension are made by aluminum
alloy 2024 which gives good fatigue performance, higher fracture toughness and slow
propagation rate. Boeing 737-800 has a composite airframe. Composite materials do not
corrode, do not fatigue, they are more reliable and are easier to maintain. Originally the
designed life of the airframe of Boeing 737-800 was set at 20 years, 75,000 cycles or 51,000
hours. In the aft part of the fuselage horizontal and vertical stabilizer are attached to it. The
radome (Radar DOME) is an aerodynamic fairing which is located in the front part of the
fuselage and houses the weather radar and ILS localizer and glideslope antennas. Unlike the
rest of the fuselage the radome is made by fiberglass to allow the RF signals through. There
are many drain holes located on fuselage, wings and empennage. The primarily purpose of
these drainage system is to prevent fluids such as leaking waste water, condensation or any
other fluid collecting in the fuselage which may become corrosion or fire hazard. Drain holes
in pressurized areas of the fuselage have a valve behind them which seals during flight and re-
opens on the ground.
FLIGHT SIMULATOR TEST SESSION
Series of experimental sessions were conducted in order to investigate the role of fuselage in
relation to aircraft performance. The fuselage width was increased with 0.50m. The aircraft
was tested during take-off so to be examined how the aircraft changed its take-off length and
time required to lift off the ground. In addition the Boeing was tested inflight to see how the
load factor increases with fuselage enlargement and increased weight. As a result the overall
drag of the aircraft increased dramatically. That includes parasite, induced and compressibility.
Based on that, the critical Mach number reduced by 0.05 and increased the overall. It was
observed an increase in take-off distance and thrust configuration with 15%. Consequently the
fuel consumption raised with 12% per passenger. The increase in mass requires a higher lift
force to be produced by the wings. Mass increase resulted in aircraft performance. The initial
take-off time was 34.1 sec. After applied changes the time increased with 3 sec. In addition,
during inflight the aircraft was exposed to a lot higher load factor compared to take-off. The
load factor inflight during session reached the max value of 10g compared to take-off where
the max value was approximately 2g. Change in vertical climb rate was observed as well. The
normal climb rate of Boeing 737-800 till reaching the cruise level is 1800 ft./m. After changes
implementing the climb rate was reduced to 1400 ft./m. Adding extra sections (‘plugs’) in front
of the wings resulted in a CG change towards the forward limit which caused:

AVIA 1000. 2015/16. Boeing 737
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 An increase in in lateral and longitudinal stability
 An increase in the take-off distance required
 An increase in the thrust setting
 A decrease in the controllability of the aircraft
Adding extra sections (‘plugs’) behind the wings resulted in a CG change towards the aft limit
which caused
 A decrease in lateral and longitudinal stability
 A decrease in the take-off distance required
 A decrease in thrust setting
 An increase in aircraft controllability
Figure 12: Fuselage width vs. Drag coefficient
In conclusion, it can be said that drag increase proportionately with the increase the fuselage
width. With the fuselage enlargement and adding new extra section, the center of gravity is
driven to change by the new section configuration. With the increased take-off weight and drag
coefficient the aircraft is required to use more thrust and pays with more fuel which makes it
less fuel efficient.
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
3.76 3.88 4 4.26
Dragcoefficient
Fuselage width (m)

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7. Undercarriage: (1046)
The undercarriage also known as the landing gear. The undercarriage is used for the following
procedures; holding dead weight when at a standstill, taxiing, take-offs and landings. When the
aircraft is landing the landing forces can reach up to several times the mass of the aircraft itself.
Modern day aircrafts have the tricycle gear undercarriage where the smaller wheel is placed at
the nose (this is called the nose wheel) of the aircraft and the main gears are placed near the
centre of gravity these are made up of two or more wheels [29]. On all the versions of the 737’s
(Original, Classics, NGs and Max) they all have the tricycle gear undercarriage. None of the
737’s has had a full main gear door. So in its place the outer wall of the tyres meets with
aerodynamic seals in the wheel well so that a smoother surface is created alongside the
undercarriage of the aircraft, as shown in figure. Originally on the first few 737’s inflatable
seals that were inflated by bleed air when the gears were either up or down and deflated during
transit. This was soon dropped as it was too complex and with the modern fixed rubber seals a
similar drag and noise advantage was achieved [30].
Figure 13: Storage column for landing gear during flight [30].
The breaks of the 737 are made from a steel alloy called Cerametalix(R) with two different
forms made by Honeywell or Goodrich. The 737 NG has had a carbon break choice, these
breaks from Goodrich or Messier-Bugatti both weigh 300kg lighter than steel and last double
the expectancy of the steel alloy breaks [30].
Figure 14: Brakes of the 737 [30].

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The brake pressure gauge should normally show 3000psi. The autobrakes and the normal break
system are powered by hydraulic system B. If the break pressure drops below 1500psi,
hydraulic system a will automatically provide alternate brakes that are manual only and the
break pressure will return to 3000psi [30].
Weight distribution between the main gears and the nose wheel are vital for manoeuvrability
and steadiness while on the ground. If the weight distribution is off on the gears for instance if
a considerable amount of weight is on the nose wheel of the aircraft, when building up speed
on the for take-off the aircraft can lose control and swerve off the runway and crash. And if too
much weight is the main gears of the aircraft, the aircraft can topple back when speed is built
up for take-off.
On large commercial aircrafts multiple wheeled trucks are used to reduce wheel load on the
runways. Retractable landing gear retract into the fuselage or the wing sections while the air
craft is in flight. Once the landing gear have been retracted and stowed into the wheel wells,
the gears are out of the way of the slipstream and no parasite drag is created. The majority of
retractable landing gear have close fitting panels, they fair with skin of the aircraft when the
gears have completely retracted. (U3) For supporting the 737 while it is taxied, the force of the
impact while landing is controlled by the landing gear. There are two ways this is done: the
first is the shock energy is that is absorbed is converted into heat heat energy and the second,
the shock energy on touchdown is changed and shifted through the airframe at an altered rate
and time than the single strong pulse of impact. (U3
Undercarriage Data
The Merlin Engineering Flight Simulator was used to alter a few small changes. While on the
simulator we chose the 737 - 800 model, the 737 would reach a ground speed of up to 145
knots before take-off within the space of 40seconds.
The Boeing 737 - 800 is supported by six wheels. A few experiments regarding the landing
gear were done. The reason these experiments were done was to see how the performance of
Boeing 737 – 800 was affected by where the position of the landing gear is. The data from the
experiment of the Merlin Engineering Flight Simulator was collected and it was compared so
that a difference can be seen the Boeing 737 – 800’s performance.
When the changes were made on the simulator, where the centre of gravity was at -5 and the
centre of pressure was at -1 the pilot of the pilot said it was a lot harder for the pilot on the
simulator said he was finding it difficult to control the aircraft and it was a lot harder to take
off. This meaning the controls were a lot stiffer and more force was required to control the
aircraft. The Euler pitch attitude started off at a minus degree number but as speed was

AVIA 1000. 2015/16. Boeing 737
23
gradually built up the pitch was more was not controllable and the nose wheel would start
digging down into the ground. As shown in table 3 and figure 15.
Table 3: Mach number and Euler pitch attitude when centre of gravity is -5 and centre
pressure is -1
Mach number Euler pitch attitude
0.8306 -16.68
0.8293 13.08
0.7764 29.75
0.7483 -26.57
0.7092 -26.3
0.7225 -19.36
0.7289 12.74
0.6904 22.64
0.6859 -14.71
0.6881 5.83
0.6872 6.1
Figure 15: Mach number vs Euler pitch attitude
When the centre of pressure was at minus 1 while during the take of sequence part of the
experiment the and as shown on table 4 and figure 16, the correlation in Mach number and the
Euler pitch attitude is the higher the Mach number the higher the Euler pitch attitude.
-30
-20
-10
0
10
20
30
40
1 2 3 4 5 6 7 8 9 10 11
Machnumber
Euler pitch
mach number euler pitch

AVIA 1000. 2015/16. Boeing 737
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Table 4: Mach number and Euler pitch attitude when CP x coordinate was -1
When the centre of pressure was at minus 1 while during the mid-flight sequence part of the
experiment the and as shown on table 5 and figure 17, the correlation in Mach number and the
Euler pitch attitude is the higher the Mach number the higher the Euler pitch attitude.
Table 5: Data of the Mach number and the Euler pitch data
0.08484 -3.42
0.8761 -1.55
0.9046 -1.44
0.9322 1.81
0
5
10
15
20
25
1 2 3 4 5 6
Machnumber
Euler pitch
mach number euler
0.0078 5.02
0.0703 4.88
0.128 4.4
0.1745 4.06
0.2107 2.95
0.2101 21.4

AVIA 1000. 2015/16. Boeing 737
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8. Wings: (1153)
Swept Wings
Like many airline planes, the wings are swept back with a slight dihedral angel. Swept wings
are defined as when the angle between the leading edge of the wings and the centreline of the
fuselage meet at an acute angel (>90) [31].
A key feature of swept back wings is its aerodynamic affects near the speed of sound, the
transonic region of speed. The
maximum cruising speed of a 737 is
472 knots. This is slightly faster than
the average turbofan-powered narrow-
body commercial passenger plane [32].
The speed of sound travels at around
574 knots at the cruising altitude of a
737 [33]. This is about Mach 0.82
which is just entering the transonic
region. If the aircraft was to make an
emergency rapid descent, the speed will
be much greater.
On non-swept wings, above around 400
knots, the drag of an aircraft starts to act in a less typical manor, especially around the wings.
As the speed increases further, shock waves form which drastically increase drag. This affect
can be observed at the ‘critical Mack number’. Achieving speeds past the critical Mack number
can be quite challenging due to the incredibly steep increase of drag per unit of speed past this
value [35].
Swept back wings affect the fluid compressibility which in turn delays the speed at which shock
-4
-3
-2
-1
0
1
2
3
1 2 3 4
Machnumber
Euler pitch
mach number euler
Figure 18: Boeing 737-700 Profile Diagram [34].

AVIA 1000. 2015/16. Boeing 737
26
waves and accompanying aerodynamic drag form. This allows planes with swept back wings
to cruise at faster speeds than airplanes without such wings. The wings of the Boeing 737 are
swept at an angle of 25.02 [4]. This angle can be altered of the aircraft can be modified in the
Merlin Flight Simulator to see if the cruising speed is really affected and by how much.
Dihedral Wings
Wing dihedral describes the angle between an aircraft’s wings and the horizontal. Dihedral
wings describe wings that are angled upwards and anhedral wings are wings that point down
towards the ground.
There are three planes of axis for fixed wing planes (lateral, longitudinal and normal). They
are each controlled by a specific control surface (elevator, ailerons and rudder respectively).
Equilibrium attitude is achieved in the lateral and normal axis after elevator and/or rudder
inputs are neutralized. This is due to the horizontal and vertical stabilizers. No such mechanism
is present for longitudinal stability. This leads to adverse yaw in rolls, an undesired affect [36].
By angling the wings up, the lower wing of a roll will have a greater angle of attack than the
higher wing. This means that the lower wing will generate a greater lift than the higher wing.
This acts as a restoring force to return the plane to straight and level flight when control inputs
are neutralized. This also means that the lower wing will be creating more drag than the higher
wing. This will counter the effect of the adverse yaw [36].
Too great of an angle can be detrimental. If an aircraft is too laterally stable, it will be
directionally unstable and prone to Dutch rolls. This is when the direction of turning is always
out of phase with the rolling motion.
The Boeing 737 has dihedral wings with 6 to the horizontal [4]. This angle has been
specifically designed to balance the advantages and disadvantages of dihedral illustrated prior.
The Merlin Flight Simulator can be used to test the effect on flight performance and roll
stabilisation when the dihedral angel is changed.
Wing Sweep Data
Our model of the 737-800 was loaded in flight traveling at an indicated air speed of 325 knots
(Mach 0.832) at 30,000ft. The aircraft was flown straight and level for 40 seconds.
This was repeated with different angles of swept wings. The angles included 15, 20, 30 and
35. Figure 19 illustrates the speed against time for the whole course of the experiment.

AVIA 1000. 2015/16. Boeing 737
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Figure 19: Mach number Against Time, 5s-40s
A pattern is hard to draw from this data. The data is clearer if it is split up into the start of the
experiment and the end of the experiment. Figure 20 displays the start of the experiment and
Figure 4 displays the end of the experiment.
0.84
0.86
0.88
0.9
0.92
0.94
0.96
0.98
1
5 10 15 20 25 30 35 40
MachNumber
Time (s)
15 20 30 35
0.84
0.85
0.86
0.87
0.88
0.89
0.9
5 6 7 8 9 10 11 12 13 14 15
MachNumber
Time (s)
15 20 30 35

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The 35 sweep aircrafts is traveling a lot faster than the other aircrafts in the early stage of
flight. The 30 and 20 aircrafts are traveling at roughly the same speed and the 15 aircraft is
traveling slightly slower.
Figure 21 shows that at the end of the experiment, the speeds of the altered aircraft were quite
evenly separated. The speed is proportional to the angel of sweep of the wings. The 35 sweep
aircraft being the fastest, then 30, 20 and finally 15 being the slowest. All aircrafts entered
the supersonic region after 38 seconds.
Wing Dihedral Data
The first wing dihedral experiment was repeated four times, once for each dihedral angel. The
flight was set up identically to the predecessor experiment. Maximum right rudder was then
applied and released.
The dihedral angels recorded were the standard 6, 12, 0 and then an anhedral angel of 6.
Observations were made about the lateral stability. The first observation that was made in the
sim was that the 6 and 12 aircrafts rolled left while the 0 and -6 aircrafts rolled right. This
is opposite to the direction of applied rudder. Figure 22 illustrates the effect of rudder inputs
on the roll attitude. It is undesirable for an aircraft to roll away from the yawed direction.
0.96
0.965
0.97
0.975
0.98
0.985
0.99
0.995
1
1.005
1.01
30 31 32 33 34 35 36 37 38 39 40
MachNumber
Time (s)
15 20 30 35

AVIA 1000. 2015/16. Boeing 737
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Figure 22: Roll Attitude against Pedal Position
The anhedral aircraft rolled to a much greater attitude than the dihedral aircraft.
The next observation made was from the recorded data. This was the scalar body axis roll
acceleration recorded the second after the rudder inputs were released. These results can be
observed in table 1.
Table 6: Roll Acceleration of Aircrafts
Dihedral Angel/ Scalar Body Axis Roll Acceleration/ms-2
-6 32.41
0 6.55
6 14.77
12 43.68
The standard angel of 6 had a roll acceleration of 14.77ms-2. Double the angel to 12 almost
triples the roll acceleration. Removing dihedral from the wings reduces the roll acceleration by
over a half. Interestingly, by applying the exact same angel of anhedral, the roll acceleration
doubled though the acceleration was in the opposite direction.
Another experiment was done in which each aircraft was loaded at rest on a runway. The test
pilot then tried to take off. The 6 aircraft could take off with minimal issue. The 12 aircraft
fell victim of Dutch rolls and was un-flyable. The 0 aircraft couldn’t rotate before running off
the end of the runway. The -6 aircraft was far too unstable to pilot.
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
-140 -120 -100 -80 -60 -40 -20 0 20 40 60 80PedalPosition
Roll Attitude/
-6 6

AVIA 1000. 2015/16. Boeing 737
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Wing Conclusion
The angle of the sweep of the wings and dihedral are critical properties in the performance of
the aircraft. The sweep of the wings is essential to reach higher speeds in flight. I believe that
the current angel of 25 allows adequate speeds but if higher speeds are needed, a greater sweep
could be used. I believe that the current dihedral angel of 6 is the most ideal angel as it delivers
a great lateral stability without hindering flight performance.
9. Tail: (1099)
Variations:
The tail of an aircraft is a component of great significance, as it controls the aircraft’s
movement about 2 of its 3 directional axes. The tail consists of elevators, which pitch the
aircraft about the lateral axis, the rudder, which yaws the aircraft about the normal axis, and
vertical and horizontal stabilisers to help maintain the desired attitude in flight. However, the
configuration of these individual sections can vary between aircraft, offering different
advantages for aircraft with different purposes.
The most common type of tail has a horizontal stabiliser and elevators positioned in line with
the fuselage and a vertical stabiliser with an attached rudder rising from the centre of the
horizontal stabiliser, commonly referred to as a conventional tail. The Boeing 737 uses this
type of tail, as seen in figure 23, with a failsafe control system where, if the hydraulics should
fail, the aircraft can fly using servo tabs [37][38].
Some aircraft, such as the Avro RJ-85, use a T-tail, which is similar to the conventional tail,
but the horizontal stabiliser is positioned at the top of the vertical stabiliser rather than at the
Figure 23: Conventional tail of a Boeing 737-300 [40].

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base (Figure 24). This configuration is most commonly found on high-wing aircraft, where the
conventionally placed horizontal stabiliser would be caught in the turbulent downwash of the
wings. By raising the stabiliser, it is removed from this turbulent airflow, thus maintaining
control. However, in the event of a stall at high angles of attack, the wings produce a turbulent
wash due to a larger surface area being presented to the relative airflow. The horizontal
stabiliser is caught in this wash, rendering the elevators useless and making it almost impossible
to recover from the stall [40]. Safety systems such as stick shake are used to prevent stalls from
occurring [41], but these raise the cost of the aircraft, making the high-wing T-tail option
undesirable unless absolutely necessary.
As a compromise between a conventional tail and a T-tail, the cruciform tail was developed,
as seen on the Sud Aviation Caravelle. In this configuration, the horizontal stabiliser is placed
partway up the vertical fin to remove it from turbulent airflow (Figure 25). This type of
positioning is often found on aircraft with aft mounted engines where, in conventional
configuration, the horizontal stabiliser would be in the engines’ wake. The design presented
difficulties however as the intersection with the fin produced undesirable drag [43].
Figure 24: T-tail configuration of an Avro RJ-85 [42].

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The V-tail has no horizontal or vertical stabilisers, but instead has two stabilisers arranged in a
V shape on the tail, used on earlier versions of the Beech Bonanza. These stabilise the aircraft
in much the same way as vertical and horizontal stabilisers, but, due to the fact that they are
placed at an angle, their control surfaces can act as both a rudder and elevator. The V-tail uses
fewer lifting surfaces than other forms of tail, so it therefore has a lower surface area, and thus
produces less drag. A lower amount of material used also means that it is lighter than other tail
configurations [45].
Figure 26: V-tail of a Beech V35A Bonanza [46].
Twin rudder tails have a vertical stabiliser on each end of the horizontal. This can be connected
to either a single tail, as seen on the Antonov An-225, or can bridge across two tails in a twin
boom configuration, such as in the F-82 Twin Mustang. Having two rudders offers a larger
control surface area, meaning that the aircraft has more effective yaw control. Furthermore, the
Figure 25: Cruciform tail of a Sud SE-210 Caravelle [44].

AVIA 1000. 2015/16. Boeing 737
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vertical stabilisers act in a similar way to tip tanks, reducing induced drag generated by the
horizontal stabiliser [47].
Additional components also feature on the tails of aircraft, such as trim tabs, allowing pilots to
adjust the aerodynamic properties of control surfaces and relieve pressure from the control
column [49]. The tail of the 737 also houses the cooling system for the aircraft’s auxiliary
power unit, identifiable by the exhaust and inlet ducts on the tip of the tail [37][38].
Flight Simulator Data:
In order to learn more about the role of the tail and how its orientation affects the flight
performance of the aircraft, several experiments were conducted, two of which will be
discussed here.
Whilst testing the aircraft model, it was observed that it had a tendency to pitch forward onto
the nose wheel during take-off, sending it off the runway. To try to correct this, the coefficient
of lift of the tailplane was changed to see if it could create a balancing moment and take weight
off the nose wheel. The coefficient was initially set to 0.5 and the model was flown through a
take-off. This was repeated for a coefficient of 1.0. The data for this test is shown in figure 28,
showing time versus lateral stick input from the pilot. The data shows that the pilot had to pull
back on the controls less with higher coefficients of lift, showing that it did indeed create a
balancing moment. This moment can also be seen to allow the aircraft to take off in a shorter
space of time, a feature which could be useful in the future design of aircraft.
Figure 27: Twin rudder tail of an Antonov An-225 [48].

AVIA 1000. 2015/16. Boeing 737
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Figure 28: Graph of stick position versus time during take-off with regards to changes
in the coefficient of lift of the tailplane.
A second test explored the effects of changing the setting angle of the tailplane, the data for
which can be seen in figure 29, measured with the same parameters as the previous experiment.
First, the tailplane angle was changed from its original position to 3°. The pilot reported that
they could not detect a great difference, so the setting was changed to 10°, to which the pilot
said that the aircraft was much more difficult to handle and to lift off. Finally, the setting angle
was changed to -10° as it was thought that positive setting angles were giving a turning moment
in the wrong direction. The pilot reported that the new angle stopped the aircraft nose from
dipping on take-off, and that take-off was much easier to accomplish. These reports are
supported by the data which show that a -10° setting angle required less stick input to get the
aircraft airborne.
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0 10 20 30 40 50
LongitudinalStickPosition(+/-1)
Time (s)
CoL 0.3 (Original)
CoL 0.5
CoL 1.0

AVIA 1000. 2015/16. Boeing 737
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Figure 29: Graph of stick position versus time during take-off with regards to changes
in tailplane setting angle.
Though this experiment into the simulator model construction went part-way to solving the
model’s issues, it was not a perfect solution to the problems encountered as aircraft typically
only have a 1˚/2˚ tailplane setting angle [50], but the test had to go as far as -10° before the
model showed signs of improvement. Furthermore, in cruising flight at altitude, the simulator
displayed that approximately 420% nose up trim was required to keep the aircraft in level flight,
so it can be deduced that the problems encountered were not likely to lie in the tailplane.
10. Conclusion: (251)
As an overall,the overviewof the projectisthat substantial informationwasobtainedonthe Boeing
737 generation, specifically the -800. The information gathered was through researching specific
aspects of the aircraft in detail. It was concluded that the 737-800 is an improved aircraft which is
environmentallyfriendlyandit has a reductioninfuel consumptionby8% due to the use of CFM-56
engine. By altering and simulating certain experiments on the MerlinEngineering Flight simulator, it
was concludedthatsome changeshad an effectonthe performance of the aircraft,for example:the
fuselage diameter was increased as well as elongating the fuselage by adding two extra sections in
front and behindthe wing.Itwas noticedthat the drag coefficientaswell asweightincreasedwhich
resulted in higher thrust setting and fuel consumption. Furthermore, moving the centre of gravity
backwardsby 5 m and movingthe centre of pressure forwardsby1 m resultedinanunstable aircraft
where it was hardly controllable. This led to evidence such as there are limits on where the position
of bothCG and CP couldbe at. Whenregardingwings,itwas concludedthatthe sweepof the wings
and the dihedral are critical in terms of the performance of the aircraft, however if higher speed is
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0 10 20 30 40 50
LongitudinalStickPosition(+/-1)
Time (s)
Setting Angle -3 Degrees
(Original)
Setting Angle 3 Degrees
Setting Angle 10 Degrees
Setting Angle -10 Degrees

AVIA 1000. 2015/16. Boeing 737
36
needed,anincreasedsweepwouldbe the solutionforthat. Finally,itwasconclude thatthere might
be fault in the construction data due to some of the data obtained being unreliable.
11. Acknowledgments: (131)
Working as a group was a good way to get the project done correctly and properly. This is
because there was an opportunity to have discussions between the group members.
Furthermore, members had either similar or different opinions about the aircraft’s aspects
made the group produces better quality work. The formal meetings the group had are
provided in the appendix section.
Each member of the group has contributed by doing at least one section, however the group
sections were not done by all members. The following are the sections that have been done
by more than one person and who contribute in them.
 Introduction: Zulk and Ikram
 Executive summary: Aous
 Design: Aous, Jonny, Ikram and Joshua
 Ethics: Joshua and Jonny
 Conclusion: Peter
 Acknowledgments: Ikram, Joshua
12. References:
(1) The 737 technical site. History, developments and variants of the Boeing
737.[Online].1999 [17/116] Available from: http://goo.gl/pQGiBz
(2) Baciu, J. Top Speed’s website. 1998-2010 Boeing 737-800. 2010 [12/1/16]
Available from: http://goo.gl/vJHquR
(3) Redding, R. Yenne, B. 1997. Boeing: Planemaker to the World. California: Thunder
Bay Press
(4) Brady, C. The 737 Technical Site. [Online]. 1999. [22/12/15]. Available
from: http://goo.gl/XHzney
(5) Frawley, G. The International Directory of Civil Aircraft. Australia: Aerospace
Publications, 2003.
(6) Boeing’s website. Boeing Freighter Family: Leading the Air Cargo Industry.
[Online]. 2015 [20/1/16] Available from: http://goo.gl/zFMS3H
(7) Airliners website. The Boeing 737-800/900. 2015. [12/1/16]. Available from:
http://goo.gl/YnDBBZ
(8) Boeing’s website. Next Generation 737. [Online]. 2015. [12/1/16] Available
from: http://goo.gl/zlW909
(9) Boeing Commercial Airplanes. 737 Airplane Characteristics for Airport
Planning. [Online]. 2013. [25/11/25]. Available from: http://goo.gl/7yxO7z
(10) European Aviation Safety Agency. Certification Specifications and
Acceptable Means of Compliance for Large Aeroplanes. [Online]. (25.901).
Available from: http://goo.gl/G5b8GE

AVIA 1000. 2015/16. Boeing 737
37
Acceptable Means of Compliance for Large Aeroplanes. [Online]. (25.903). Available
from: http://goo.gl/G5b8GE
Acceptable Means of Compliance for Large Aeroplanes. [Online]. (25.613).
Available from: http://goo.gl/G5b8GE
(13) Kowal, J. Boeing Commercial Airplanes and the Environment. [Online].
2015. [12/1/16]. Available from: http://goo.gl/mT8SaO
(14) Boeing tests noise-reduction, fuel-efficiency technology on 737-800.
King 5. [Online]. September 18th, 2012. [12/1/16]. Available
from: http://goo.gl/YSXabF
(15) Aviation Week Network. Mystery 737 Winglet Test. [Online]. 2012.
[12/1/16]. Available from: http://goo.gl/ejU84P
(16) Aviation Safety Network. Boeing 737 Statistics. [Online]. 2016.
[12/1/16]. Available from: http://goo.gl/fztCZn
(17) Boeing Commercial Aeroplanes. Statistical Summary of Commercial
Jet Airplane Accidents. [Online]. Seattle: Aviation Safety. [2/1/16]. Available
from: http://goo.gl/b8y10Y
(18) Boeing Commercial Airplanes. 737 Airplane characteristics for airport
planning. [Online]. July 2007. [7/1/16]. Available from: http://goo.gl/aI3ZfS
(19) Pooleys. The Aeroplane-Techinical. Vol4. 2014. Air pilot
publishing LTD. England.
(20) Weight and balance. Centre of gravity limitations. [Online]. [Accessed
on 13th January 2016]. Available from: http://goo.gl/XZDy6L
(21) Brady, C. The Boeing 737 Technical Guide. [Online]. (Pocket Budget
version). Tech pilot service LTD. 2015 [8/1/16]. Available from:
https://goo.gl/HEZDmJ
(22) Brady, C. The 737 Technical Site, Powerplant. [Online]. 1999. [3/1/15].
Available from: http://goo.gl/Tpg23k
(23) CFM. Turbofan engine. [Online]. 2012. [4/1/16]. Available from:
http://goo.gl/1TD4Es
(24) JAA Jeppesen: Airframes and systems, Oxford: Oxford Aviation, 2007
(25) Oxford aviation training: Aircraft general knowledge, Airframes and systems.
Oxford: Oxford Academy, 2004
(26) Boeing 737-800 fuselage [online] [17/1/16] Available from:
http://goo.gl/7mPYpF
(27) Semi-monocoque structure [online] [17/1/16] Available from:
http://goo.gl/J40UfR
(28) J.P. Fielding: Introduction to Aircraft Design CUP, Cambridge: Cambridge
University Press, 1999.
(29) Crane, Dale: Dictionary of Aeronautical Terms, third edition, page 524.
Aviation Supplies & Academics, 1997
(30) Brady, C. The 737 Technical Site, Landing Gear. [Online]. 1999.
[2/1/16]. Available from: http://goo.gl/VQrOa3
(31) Atkins, T and Marcel, E. A Dictionary of Mechanical Engineering.
Oxford: Oxford University Press, 2013
(32) axlegeeks. Boeing 737-800 Detail. [Online]. 2014. [25/12/15]. Available
from: http://goo.gl/rNHHxQ

AVIA 1000. 2015/16. Boeing 737
38
(33) Fight Planes. Speed of Sound at Different Altitudes. [Online]. 2002.
Available from: http://goo.gl/b6ojIz
(34) Skybrary. Boeing 737-700. [Online]. 2013. [25/12/15]. Available
from: http://goo.gl/Q51y2D
(35) Garrison, P. Why Are Wings Swept? 24th of January. FLYING.
[Online]. 2009. [25/12/15]. Available from: http://goo.gl/6dEfr7
(36) Kuhlman, B and Kuhlman, B. Swept Wings and Effective Dihedral. RC
Soaring Digest. March 2000, 3-5. Available online: http://goo.gl/4L63Uh
(37) Brady, C. 2015. Auxiliary Power Unit. [Online]. [19/01/2016]. Available
from: http://goo.gl/aaYxRX
(38) Brady, C. 2015. Flight Controls. [Online]. [19/01/2016]. Available from:
http://goo.gl/7uFHrs
(39) Gupta, S. 2001. Lock On Aviation. [Online]. [28/12/2015]. Available from:
http://goo.gl/VLrBnD
(40) SKYbrary. 2015. Deep Stall. [Online]. [19/01/2016]. Available from:
http://goo.gl/BRl3Lz
(41) Cox, B. 2013. The Reality of Deep Stalls. [Online]. [19/01/2016]. Available
from: http://goo.gl/j2Zc8t
(42) von Wedelstaedt, K. 2015. Airliners.net. [Online]. [28/12/2015]. Available
from: http://goo.gl/gmx2rv
(43) McClellan, J. M. 1983. Sunset on T Tails. [Online]. [19/01/2016]. Available
from: https://goo.gl/T2OmO4
(44) Popelar, P. 1986. Airliners.net. [Online]. [28/12/2015]. Available from:
http://goo.gl/uRdRM5
(45) Raymer, D. P. 1999. Aircraft Design: A Conceptual Approach. 3rd Edition.
Virginia: American Institute of Aeronautics and Astronautics
(46) Bergmann, R. 2015. Airliners.net. [Online]. [28/12/2015]. Available from:
http://goo.gl/Vqthri
(47) Kroo, I. 2005. Tail Design and Sizing. [Online]. [08/01/2016]. Available from:
http://goo.gl/clKNMA
(48) Xu, J. 2013. Airliners.net. [Online]. [28/12/2015]. Available from:
http://goo.gl/7I9l6v
(49) Mola, R. 2013. How Thing Work: Trim Tabs. [Online]. [19/01/2016].
Available from: http://goo.gl/KO0i2g
(50) Sadraey, M. 2013. Aircraft Designing: A Systems Engineering Approach.
[Online]. [19/01/2016]. Available from: http://goo.gl/FMhvdj
13. Appendix:
Wing Appendix
Table 1: -6 Dihedral Data
Euler Roll Attitude/ Body Axis Roll
Rate/ms-1
Body Axis Roll
Acceleration/ms-2
Pedal Position
0 0 0.09 -0.01
-0.01 0.31 1.02 -0.34
-9.48 -26.51 -42.23 -0.75

AVIA 1000. 2015/16. Boeing 737
39
-45.96 -39.22 -2.9 -0.75
-88.8 -42.55 3.06 -0.3
-118.39 -8.25 32.41 -0.01
Table 2: 0 Dihedral Data
Rate/ms-1
Body Axis Roll
Acceleration/ms-2
Pedal Position
0 0.02 1.12 0
-0.07 0.25 3.19 -0.28
-1.62 -4.66 -13.47 -0.76
-10.02 -8.53 0.67 -0.76
-19.27 -10.08 -1.21 -0.47
-26.91 -3.93 6.55 -0.02
-28.55 -0.53 1.1 -0.01
-28.82 -0.2 0.3 -0.01
Rate/ms-1
Body Axis Roll
Acceleration/ms-2
Pedal Position
0 -0.16 -15.7 0
-1.54 -0.89 2.3 -0.12
0.16 8.41 17.14 -0.72
15.43 21.53 4.68 -0.76
37.86 21.8 -6.68 -0.36
54.64 6.32 -14.77 0
57.11 0.91 -1.66 -0.01
57.22 -0.15 0.16 -0.01
56.95 -0.23 -0.09 -0.01
56.57 -0.2 -0.05 -0.01
Rate/ms-1
Body Axis Roll
Acceleration/ms-2
Pedal Position
0 0 0 0
0 0 0.02 -0.03
3.43 16.17 42.65 -0.7
39.84 51.4 9.48 -0.76
95.41 53.43 -4.67 -0.47
136.96 20.61 -43.68 -0.01
144.87 2.97 -3.53 0

AVIA 1000. 2015/16. Boeing 737
40
Group Meeting One 11/1/16
 Discussed how much we’ve done
 Discussed if we want to focus on a specific 737
 Going to move some content from other sections to history
 Who will fly in the sim?
o Each fly their own section
o (Joshua ended up flying all sections)
 Whoever we need to book a second sim session
o Will see how the first session goes
 Confirm meeting in Laid Law tomorrow
o Disused further room booking
o AM or PM slots
 Need to ask Darron about power point contents
 Who speaks in presentation
o Zulk & Jonny who rather not to present
 Weekend meeting
 Numeric results from sim?
 Maybe decide what 737 to focus on from what is available on the sim
 To what degree we can change variables on the sim
Time: 21 minutes 24 seconds
Group Meeting 2: 12/1/16
 Early start inthe Laid Law Library
 Needaspecial programto openthe data recordingfromthe sim
o PossiblyAutocad2016
o (turnedoutto be a special methodwithExcel
 Eassa documentonthe 737 found
 Google drive with useful documents created
 Ikram to gather resources for Aircraft Design
 Josh to start ethics
 Jonny to gather information of safety failure
Time: 4 hours 30 minutes
 Started researching about the design of the aircraft.
 Discussed the progress of the individual sections.
 Finished off the introduction and decided to add the Gantt chart to it.
 Plan for the next meeting.
Time: 2 hours

AVIA 1000. 2015/16. Boeing 737
41
 Ikram has gone to book a lecture theatre to practice presentation tomorrow
 We will first work on our individual data sections
 Jonny writes labels for data spreadsheet
 Ikram creates Gantt chart
 Peter leaves for conflicting meeting and returns later
 Another group joins us
 Jonny leaves to improve own section further as crucial website is blocked on the wifi
 Josh finishes individual section
 Various sections completed including acknowledgments and abstract
 Lecture theatre for tomorrow successfully booked
 Started working on presentation
Time: 8 hours, 30 minutes
 Made a list of topics to ask Darron in meeting later in the day
 Meeting with Darron:
o Power point is too dense with information
o Increase amount of slides to 9-11
o Most of marks aren’t from speaking
 Aous, Josh and Jonny all add content to design
 We go to lecture theatre to add to presentation slides, rehearse and time our
presentation
 Spend 20 minutes improving ourselves and presentation before rehearsing again
 We start piecing together the separate sections and standardise the formatting
 We all split up proof reading and make changes
 Ikram standardises figure numbers
 All that’s left up is brushing up and standardising references
Time: 9 hours and 30 minutes

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