DEVELOPMENT OF A FIXED WING UNMANNED AERIAL VEHICLE

FOR DELIVERY

PATRICK EMMANUEL

BU/16C/ENG/2022

Department of Mechanical Engineering

Baze University

Abuja, Nigeria

February, 2020

i
DEVELOPMENT OF A FIXED WING UNMANNED AERIAL
VEHICLE FOR DELIVERY

PATRICK EMMANUEL

BU/16C/ENG/2022

Thesis submitted to the Faculty of Engineering through the Department

of Mechanical Engineering in partial fulfilment of the requirements for
the degree of Bachelor of Engineering

in

Mechanical Engineering

Baze University

Abuja, Nigeria

February, 2020

ii
 DECLARATION

BAZE UNIVERSITY

DEPARTMENT OF MECHANICAL ENGINEERING

I, Patrick Emmanuel, confirm that this report and the work presented in it are my own
achievement.

I have read and do understand the penalties associated with plagiarism.

Signed: ......................................................................................................................................

Date: ........................................................... ...............................................................................

i
 CERTIFICATION

This is to certify that this thesis is fully adequate in scope and quality as an undergraduate
project work for the award of degree of Bachelor of Engineering in Mechanical Engineering.

------------------------------ --------------------------
Dr. Irana Birada
Supervisor Date

This is to certify that this thesis satisfies the requirements as a graduation project for the award
of degree of Bachelor of Engineering in Mechanical Engineering.

------------------------------ --------------------------

Professor R.H Khan

H.O.D Department of Mechanical Engineering Date

Endorsement of External Examiner:

This is to confirm that this thesis satisfies the requirements as a graduation project for the award
of degree of Bachelor of Engineering in Mechanical Engineering.

---------------------------------------------------------- --------------------------
Name and Signature of External Examiner Date

Approval of the Faculty of Engineering:

------------------------------ --------------------------
Dr. Nurudeen Labaran Tanko Date
Dean, Faculty of Engineering

ii
 DEDICATION
I dedicate this project to God Almighty, and to my parents; Mr & Mrs Emmanuel Gakko for
the immense support and contribution towards my degree program.

iii
 ACKNOWLEDGEMENT
I appreciate God Almighty for life, good health and knowledge. I appreciate My Supervisor
Dr. Iranna Biradar, Head of Department and Lecturers for continual support throughout this
project. I appreciate the management and staff of W Steel structures for equipping me with the
knowledge and skills learnt during my internship regarding design processes.

iv
 ABSTRACT
This thesis explores the development of a fixed wing unmanned aerial vehicle for delivery given
the deplorable condition of roads leading to certain rural medical centers. This unmanned aerial
vehicle has to be of the fixed wing type due to the weight to be carried and the distance which
is to be covered. The thesis seeks to provide a greener alternative using a recyclable material
i.e. strawboard for the body of the UAV, the UAV is also of a modular design hence it can
easily be converted from being used for delivery to being used to take aerial photographs,
surveillance and any other form of application. The UAV is powered by two brushless motors
which have sufficient power to accelerate it to a given extent reaching its take off velocity and
generating sufficient lift by the wings. The drone market is a billion-dollar industry, if Nigeria
can start mass producing such in-house, this would lead to a significant increase in our current
economic state and this would as well attract foreign investment and give room for the
advancement of this given field as an academic endeavor.

Keywords: Unmanned Arial Vehicle (UAV), Delivery, fabrication, Modular

v
Table of Contents
DECLARATION ................................................................................................................... i

CERTIFICATION ................................................................................................................ ii

DEDICATION ..................................................................................................................... iii

ACKNOWLEDGEMENT .....................................................................................................iv

ABSTRACT ........................................................................................................................... v

LIST OF FIGURES .......................................................................................................... viii

LIST OF TABLES ................................................................................................................ x

LIST OF EQUATIONS ....................................................................................................... xi

CHAPTER 1: INTRODUCTION ......................................................................................... 0

1.0 Background:........................................................................................................................... 0

1.1 Research Problem: ................................................................................................................. 1

1.2 Motivation for research: ........................................................................................................ 1

1.3 Aim and objectives:................................................................................................................ 2

CHAPTER 2 ......................................................................................................................... 3

2.0 Literature review ................................................................................................................... 3

2.0.1 Classification of UAVs.................................................................................................................... 3
2.0.2 History of UAVs ........................................................................................................................... 10
2.0.3 Overview of UAV System ............................................................................................................. 11
2.0.4 General Uses of UAVs .................................................................................................................. 12
2.0.5 General Parts of a UAV ................................................................................................................. 13

2.1 Flight Physics ....................................................................................................................... 16

2.1.1 Lift ............................................................................................................................................... 17
2.1.2 Drag.............................................................................................................................................. 19
2.1.3 Weight .......................................................................................................................................... 19
2.1.4 Thrust ........................................................................................................................................... 20

2.2 Flight Dynamics ................................................................................................................... 20

2.2.1 Control Surfaces............................................................................................................................ 21
2.2.2 UAV Movements .......................................................................................................................... 22

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CHAPTER 3: MATERIALS AND METHOD .................................................................... 23

3.0 Materials Used ..................................................................................................................... 23

3.0.1 Material Cost ................................................................................................................................ 31

3.1 Fabrication of Fixed Wing Delivery UAV ........................................................................... 31

3.1.1 Time Frame(Work Schedule)......................................................................................................... 31
3.1.2 Assembly of Parts ......................................................................................................................... 32
3.1.3 Electrical Schematic ...................................................................................................................... 41

CHAPTER 4: RESULTS AND DISCUSSION ................................................................... 43

4.0 Design of Fixed Wing Delivery UAV ................................................................................... 43

4.0.1 The Fuselage (body) ...................................................................................................................... 43
4.0.2 The Nose ...................................................................................................................................... 45
4.0.3 The Main Wing ............................................................................................................................. 46
4.0.4 Tail ............................................................................................................................................... 48

4.1 Weight of UAV ..................................................................................................................... 50

4.2 Motor RPM .......................................................................................................................... 50

4.3 Lift Generated ...................................................................................................................... 51

4.4 Stress Analysis...................................................................................................................... 53

4.5 Flight testing......................................................................................................................... 55

CHAPTER 5 ....................................................................................................................... 56
5.0 Conclusion....................................................................................................................................... 56
5.1 Recommendation ............................................................................................................................. 56

REFERENCES .................................................................................................................. 57

vii
LIST OF FIGURES
FIGURE 2.1 VERY SMALL UAVs[5] ................................................................................. 6
FIGURE 2.2 SMALL UAV[5] .............................................................................................. 6
FIGURE 2.3 EXAMPLES OF MEDIUM SIZED UAVs[5] ................................................... 7
FIGURE 2.4 EXAMPLES OF LARGE UAVs[5] .................................................................. 8
FIGURE 2.5 SOME CONFIGURATIONS OF FIXED-WING UAVs[7] ............................... 9
FIGURE 2.6 EXAMPLES OF ROTARY-WING UAVs[7] ................................................... 9
FIGURE 2.7 EXAMPLES OF AIRSHIP-BASED UAVs[7] .................................................. 9
FIGURE 2.8 MICRO FLAPPING-WING UAVs[7] .............................................................. 9
FIGURE 2.9 THE CURTISS N2C-2 DRONE[3] ................................................................. 11
FIGURE 2.10 SHOWING THE “SPLIT” OF FLUID FLOW PAST AN AIRFOIL TO
GENERATE LIFT[10] ........................................................................................................ 18
FIGURE 2.11 FORCES ACTING ON AN AIRCRAFT[10] ................................................ 20
FIGURE 2.12 CONTROL SURFACES ON UAVs[12] ....................................................... 21
FIGURE 2.13 PICTORIAL REPRESENTATION OF UAVs MOVEMENTS[12] .............. 22
FIGURE 3.1 STRAWBOARD ............................................................................................ 23
FIGURE 3.2 BRUSHLESS MOTORS ................................................................................ 24
FIGURE 3.3 ELECTRONIC SPEED CONTROLLER (ESC) .............................................. 25
FIGURE 3.4 LI-PO BATTERY ........................................................................................... 26
FIGURE 3.5 VARIABLE PULSE WIDTH THAT CONTROLS THE SERVO MOVEMENT
............................................................................................................................................ 28
FIGURE 3.6 SERVO........................................................................................................... 29
FIGURE 3.7 RC TRANSMITTER FIGURE 3.8 RC RECIEVER .................................. 29
FIGURE 3.9 PROPELLER FIGURE 3.10 SERVO EXTENSION WIRE ....................... 30
FIGURE 3.11 XT60 BATTERY PACK CONNECTOR ...................................................... 30
FIGURE 3.12 MEASUREING AND MARKING OUT OF THE FUSELAGE PARTS ....... 32
FIGURE 3.13 MEASURING AND MARKING OUT OF THE RUDDER ASSEMBLY .... 33
FIGURE 3.14 MEASURING AND MARKING OUT OF THE TOP OF THE FUSELAGE 34
FIGURE 3.15 CUTTING OUT OF FUSELAGE ................................................................. 34
FIGURE 3.16 CUTTING OF THE TOP OF THE FUSELAGE ........................................... 35
FIGURE 3.17 JOINING OF FUSELAGE PARTS ............................................................... 35
FIGURE 3.18 JOINT FUSELAGE SECTION ..................................................................... 36
FIGURE 3.19 JOINT FUSELAGE ...................................................................................... 36

viii
FIGURE 3.20 HORIZONTAL STABILIZER ASSEMBLY ................................................ 37
FIGURE 3.21 TAIL ASSEMBLY WITH SERVOS IN PLACE .......................................... 37
FIGURE 3.22 TAIL ASSEMBLY WITH SERVOS RODS IN PLACE ............................... 38
FIGURE 3.23 WING ASSEMBLY WITH SERVOS AND ELECTRICAL WIRINGS IN
PLACE ................................................................................................................................ 38
FIGURE 3.24 BENDING THE WING PROFILE................................................................ 39
FIGURE 3.25 NOSE ASSEMBLY ...................................................................................... 39
FIGURE 3.26 FULLY ASSEMBLED UAV ........................................................................ 40
FIGURE 3.27 ELECTRIC SCHEMA FOR THE UAV ........................................................ 41
FIGURE 4.1 DRAWING OF THE UPPER PART OF THE WING WITH DIMENSIONS . 43
FIGURE 4.2 DRAWING OF THE SIDE OF THE FUSELAGE WITH DIMENSIONS ...... 44
FIGURE 4.3 DRAWING SHOWING THE ASSEMBLED FUSELAGE ............................. 45
FIGURE 4.4 LAYOUT SHOWING THE WING ASSEMBLY ........................................... 47
FIGURE 4.5 COMPLETED UAV DESIGN ........................................................................ 49
FIGURE 4.6 ORTHOGRAPHIC PROJECTION OF THE UAV ......................................... 50
FIGURE 4.7 CHART OF COEFFICIENT OF LIFT FOR A CHAMBERED WING ........... 51
FIGURE 4.8 STRESS ANALYSIS OF UAV DURING TAKE OFF ................................... 53
FIGURE 4.9 STRESS ANALYSIS OF UAV IN FLIGHT ................................................... 54
FIGURE 4.1O STRESS ANALYSIS ON LINK BETWEEN MAIN WING AND FUSELAGE
............................................................................................................................................ 54
FIGURE 4.11 UAV IN STEADY FLIGHT ......................................................................... 55
FIGURE 4.12 UAV ASCENDING ...................................................................................... 55

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LIST OF TABLES
TABLE 2.1 CATEGORIES OF UAVS ACCORDING TO U.S. DEPARTMENT OF
DEFENSE[6] ........................................................................................................................ 5
TABLE 3.1 COST BREAKDOWN OF THE PROJECT ..................................................... 31
TABLE 3.2 DURATION OF THE FABRICATION PROCESS .......................................... 31
TABLE 4.1 LIFT GENERATED AT VARIOUS VELOCITIES ......................................... 52

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LIST OF EQUATIONS
Bernoulli equation(1)........................................................................................................... 17
Continuity equation(2)......................................................................................................... 17
Lift equation(3) ................................................................................................................... 18
Equation of Drag(4)............................................................................................................. 19
Weight(5) ............................................................................................................................ 19
Thrust(6) ............................................................................................................................. 20
Payload-weight fraction(7) .................................................................................................. 46
Wing load(8) ....................................................................................................................... 47
The Motor RPM(9) .............................................................................................................. 50
Coefficient of lift(10)........................................................................................................... 51

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CHAPTER 1: INTRODUCTION
1.0 Background:
The drone technology is an emerging field of interest in the scope of study of mechanical
engineers, the concept of unmanned aerial vehicles as a subcategory of the drone field gives
rise to aerial vehicles which are able to fly and perform various tasks without having a human
on board, the unmanned aerial vehicle can be controlled from a remote site as far as halfway
across the globe.
The drone technology is applied in various fields, for example drones are used during
disasters to find and pinpoint the exact location of survivors due to the fact that the drone is
able to relay its exact coordinates to the operators hence making it easier for rescuers to locate
survivors, drones are used in war zones to locate warring factions, drones are used for
surveillance and finally drones are also employed in mapping of the earth surface of providing
an overview of the terrain. However, the modification of drones to be used for the delivery of
various objects has been picking up slow momentum hence there is a need for comprehensive
research to be carried out in this field and adequate implementations of such modifications to
the drones.[1]
Unmanned Aerial Vehicles (UAVs) have proven their usefulness especially in military
reconnaissance in recent military conflicts. Their practical applications have been expanding to
more than military uses. Various sizes of UAVs are designed to different levels of performance
depending on their application. UAVs can be categorized into four different groups: large,
medium, small, and micro
Most of the large UAVs have higher flight ceiling, speed, and endurance with more functional
capabilities than small UAVs. Large UAVs are more suitable for large land or over-water
surveillance. The effectiveness of large UAVs has been proven in surveillance and military
operations such as The Gulf War and Desert Storm. Most mid-size UAVs do not require
runways because takeoff requires a catapult mechanism and landing uses a parachute, UAVs
of this size are commonly used for reconnaissance, delivery of small/medium sized packages,
also tactical military missions such as target acquisition, over- the-horizon surveillance, and
battle damage assessment. Micro air vehicles (MAVs) are miniature aircrafts which are
restricted by small payload capabilities such as autopilot/control system, camera(optional), and
battery, Its advantage is that its size benefit has the potential to overcome the UAV’s

0
accessibility in the confined area. Recently developed MAVs by the University of Florida have
an 11cm wingspan and 15-minute endurance, and weigh less than 40g[2]. The University of
Florida has also developed a 15cm wingspan MAV with a reconnaissance capability within
1km range with video transmitting.
The mini-cargo prototype airplane I am designing and fabricating is an example of a
modified unmanned aerial vehicle (UAV), it is a modification of a UAV that allows it to carry
objects of a certain weight within the hull.

1.1 Research Problem:

Looking at the deplorable condition of the Nigerian infrastructure especially the roads
leading to rural settlements, a safer and cheaper alternative to the regular treacherous journey
by road or expensive trips by helicopters to deliver medical supplies in this case medicines to
these rural settlement hospitals has to be devised. Hence as engineers we provide practical
solutions to real world problems such as the aforementioned. Therefore, this thesis is based on
using a fabricated UAV which is modified for delivery of emergency drugs to these hard to
reach rural hospitals or medical centers. Since the drone soars in the air, it can easily get to such
areas in record time and these greatly reduces the cost of transportation and risks involved.

1.2 Motivation for research:

Although unmanned aerial vehicles have been around for quite a while, even though the
usage of these vehicles for delivery is still in its infant stage, none so far has been developed
considering the economic and all round condition of the country. Given the lack of the
government’s willingness to sort the deplorable conditions of the aforementioned infrastructure
i.e. roads to rural settlements and my keen interest in aeronautics in general, as a mechanical
engineer I am challenged to take up such problems and proffer solutions. Another aspect that
serves as a motivation to this thesis is that once this field of UAV finds a solid footing in the
country, more of the complex electrical parts would be produced locally, this would bring in
more investors hence this doesn’t only solve a problem but also serves as a means to improve
the country economically.

1
1.3 Aim and objectives:
The sole aim of this project is to develop a fixed wing unmanned Arial vehicle which is
to be used for delivery taking into consideration the use of a locally available renewable
material.
On completion of the development of the UAV the following objectives should be achieved:
1. The fixed wing delivery UAV should be able to carry a payload of up to 0.5kg.
2. The fixed wing delivery plane should have a considerable flight time given the distance of
flights.
3. Provision of further improvements i.e camera modules should be considered.
4. The fixed wing delivery UAV should be able to drop off its payload without landing.
5. The fixed wing delivery UAV should weigh less than 2kg without the payload.

2
CHAPTER 2
2.0 Literature review
The UAV is an acronym for Unmanned Aerial Vehicle, which is an aircraft with no
pilot on board. UAVs can be remote controlled aircraft (e.g. flown by a pilot at a ground control
station) or can fly autonomously based on pre-programmed flight plans or more complex
dynamic automation systems. UAVs are currently used for a number of missions, including
reconnaissance and attack roles. The acronym UAV has been expanded in some cases to UAVS
(Unmanned Aircraft Vehicle System). The FAA has adopted the acronym UAS (Unmanned
Aircraft System) to reflect the fact that these complex systems include ground stations and other
elements besides the actual air vehicles.
Officially, the term 'Unmanned Aerial Vehicle' was changed to 'Unmanned Aircraft
System' to reflect the fact that these complex systems include ground stations and other
elements besides the actual air vehicles. The term UAS, however, is not widely used as the term
UAV has become part of the modern lexicon.
The future of drones in our skies becomes less of a Prophesy and more a fact of life by
each passing day. The industry of supply chain management may yet to have been disrupted by
such technology, however, within this field new technology is continually being adopted. These
innovations serve as catalysts which support the process of improving the delivery chain
efficiency[3].

2.0.1 Classification of UAVs

There is no one standard when it comes to the classification of UAVs. Defense agencies have
their own standard, and civilians have their ever-evolving loose categories for UAS. People
classify them by size, range and endurance, and use a tier system that is employed by the
military.
- For classification according to size, one can come up with the following sub-classes[4]:
1. Very small UAVs
2. Micro or Nano UAVs
3. Small UAVs
4. Mini UAVs
5. Medium UAVs
6. Large UAVs

3
- UAVs typically fall into one of six functional categories (although multi-role airframe
platforms are becoming more prevalent)[5]:
1. Target and decoy: providing ground and aerial gunnery a target that simulates an enemy
aircraft or missile.
2. Reconnaissance providing battlefield intelligence.
3. Combat: providing attack capability for high-risk missions (see Unmanned combat air
vehicle).
4. Logistics/Delivery: UAVs specifically designed for cargo and logistics operation.
5. Research and development: used to further develop UAV technologies to be integrated
into field-deployed UAV aircraft.
6. Civil and commercial UAVs: specifically designed for civil and commercial
applications.

- They can also be categorised in terms of range/altitude[6]:

1. Hand-held: 2,000 ft (600 m) altitude, about 2 km range.
2. Close: 5,000 ft (1,500 m) altitude, up to 10 km range.
3. NATO type: 10,000 ft (3,000 m) altitude, up to 50 km range.
4. Tactical: 18,000 ft (5,500 m) altitude, about 160 km range.
5. MALE (medium altitude, long endurance): up to 30,000 ft (9,000 m) and range over
200 km.
6. HALE (high altitude, long endurance) :over 30,000 ft (9,100 m) and indefinite range.
7. HYPERSONIC: high-speed, supersonic (Mach 1–5) or hypersonic (Mach 5+) 50,000 ft
(15,200 m) or suborbital altitude, range over 200 km.
8. ORBITAL low earth orbit (Mach 25+).
9. CIS Lunar Earth-Moon transfer.
10. CACGS Computer Assisted Carrier Guidance System for UAVs.

4
According to the U.S. Department of Defense, UAVs are classified into five categories, as
shown in table 2.1 below

TABLE 2.1 CATEGORIES OF UAVS ACCORDING TO U.S. DEPARTMENT OF

DEFENSE[6]

- The classification according to size are furthered detailed as follows:

1. Very small UAVs: The very small UAV class applies to UAVs with dimensions ranging
from the size of a large insect to 30-50 cm long. The insect-like UAVs, with flapping or rotary
wings, are a popular micro design. They are extremely small in size, are very light weight, and
can be used for spying and biological warfare. Larger ones utilize conventional aircraft
configuration. The choice between flapping or rotary wings is a matter of desired
maneuverability. Flapping wing-based designs allow perching and landing on small surfaces.
Examples of very small UAVs are the Israeli IAI Malat Mosquito (with wing span of 35 cm
and endurance of 40 minutes,) the US Aurora Flight Sciences Skate (with wing span of 60 cm
and length of 33 cm), the Australian Cyber Technology CyberQuad Mini (with 42x42 cm
square), and their latest model, CyberQuad Maxi. See Figure 2.1, below

5
 FIGURE 2.1 VERY SMALL UAVs[5]

2. Small UAVs: The Small UAV class (which also called sometimes mini-UAV) applies to
UAVs that have at least one dimension greater than 50 cm and no larger than 2 meters. Many
of the designs in this category are based on the fixed-wing model, and most are hand-launched
by throwing them in the air as shown in the figure below
.

FIGURE 2.2 SMALL UAV[5]

3. Medium UAVs: The medium UAV class applies to UAVs that are too heavy to be carried
by one person but are still smaller than a light aircraft. They usually have a wingspan of about
5-10 m and can carry payloads of 100 to 200 kg. Examples of medium fixed-wing UAVs are
(see Figure 2.3, below) the Israeli-US Hunter and the UK Watchkeeper. There are other brands
used in the past, such as the US Boeing Eagle Eye, the RQ-2 Pioneer, the BAE systems Skyeye
R4E, and the RQ-5A Hunter. The Hunter has a wingspan of 10.2 m and is 6.9 m long. It weighs

6
about 885 kg at takeoff. The RS-20 by American Aerospace is another example of a crossover
UAV that spans the specifications of a small and medium sized UAV. Many other medium
UAVs can be found in the reading assignment. There are also numbers of rotary-based medium
sized UAVs.[6]

FIGURE 2.3 EXAMPLES OF MEDIUM SIZED UAVs[5]

4. Large UAVs: The large UAV class applies to the large UAVs used mainly for combat
operations by the military. Examples of these large UAVs are the US General Atomics Predator
A and B and the US Northrop Grumman Global Hawk

7
 FIGURE 2.4 EXAMPLES OF LARGE UAVs[5]

- UAVs can be classified according to their aerodynamic configuration[6]

1. Fixed-wing UAVs, which refer to unmanned airplanes (with wings) that require a
runway to take-off and land, or catapult launching. These generally have long endurance
and can fly at high cruising speeds, (see Fig 2.6 for some examples)
2. Rotary-wing UAVs, also called rotorcraft UAVs or vertical take-off and landing
(VTOL) UAVs, which have the advantages of hovering capability and high
maneuverability. These capabilities are useful for many robotic missions, especially in
civilian applications. (see Fig. 2.6 for some examples).
3. Blimps such as balloons and airships, which are lighter than air and have long
endurance, fly at low speeds, and generally are large sized (see Fig. 2.7 for some
examples).
4. Flapping wing UAVs, which have flexible and/or morphing small wings inspired by
birds and flying insects, see Fig. 2.8.

8
FIGURE 2.5 SOME CONFIGURATIONS OF FIXED-WING UAVs[7]

FIGURE 2.6 EXAMPLES OF ROTARY-WING UAVs[7]

FIGURE 2.7 EXAMPLES OF AIRSHIP-BASED UAVs[7]

FIGURE 2.8 MICRO FLAPPING-WING UAVs[7]

9
2.0.2 History of UAVs
The history of flying objects, or the unmanned aerial vehicle in its rudimentary forms, extends
way back to ancient civilizations. The Chinese, around 200 AD, used paper balloons (equipped
with oil lamps to heat the air) to fly over their enemies after dark, which caused fear among the
enemy soldiers who believed that there was divine power involved in the flight. In the United
States, during the Civil War, both Union and Confederate forces launched balloons laden with
explosives and attempted to land them in supply or ammunition depots and explode them. As a
matter of fact, the idea of unmanned aerial objects came long before manned flights. This was
for the obvious reason of removing the risk of loss of life in conjunction with these experimental
objects. In modern times, the idea of unmanned flying objects developed to mean flying aerial
vehicles, or aircraft without pilots on board. Thanks to advancements in technology, the
maneuvering and control of piloted flight can be sufficiently mimicked. Names like aerial
torpedo, radio-controlled vehicle, remotely piloted vehicle (RPV), remote controlled vehicle,
autonomous controlled vehicle, pilotless vehicle, unmanned aerial vehicle (UAV), unmanned
aircraft system (UAS), and drone are names that may be used to describe a flying object or
machine without a pilot on board. The main challenge that faced early aerospace pioneers of
piloted and pilotless airplanes alike was the issue of controlling flight once the flying object
was up in the air. The Wright Brothers (1903), and at about the same time, Dr. Samuel Pierpont
Langley, taught the aviation world a lot about the secrets of controlled flight. Afterwards, the
war machine of WWI put intense pressure on inventors and scientists to come up with
innovations in all aspects of flight design including power plants, fuselage structures, lifting
wing configurations and control surface arrangements[2]. By the time WWI ended, modern day
aviation had been born. In late 1916, the US navy funded Sperry Gyroscope Company (later
named Sperry Corporation) to develop an unmanned torpedo that could fly a guided distance
of 1000 yards to detonate its warhead close enough to an enemy warship. Almost two years
later, on March 6, 1918, after a series of failures, Sperry efforts succeeded in launching an
unmanned torpedo to fly a 1000-yard course in stable guided flight. It dived onto its target at
the desired time and place, and later was recovered and landed. With this successful flight, the
world’s first unmanned aircraft system, which is called Curtis N-9, was born. In the late 1930s,
the U.S. Navy returned to the development of drones. This was highlighted by the Navy
Research Lab’s development of the Curtis N2C-2 drone. (See Figure 2.10). The 2500-lb. bi-
plane was instrumental in testing the accuracy and efficiency of the Navy anti-aircraft defense
system.[4]

10
 FIGURE 2.9 THE CURTISS N2C-2 DRONE[3]

World War II accelerated the development of aviation science in general and the unmanned
aircraft in particular. Both the Germans and the allies successfully utilized unmanned combat
aircraft. The most extensive program came about during the Vietnam War, as advances in
technologies made UAVs more effective. Ryan Firebee drones by Teledyne-Ryan Aeronautical
of San Diego, California were flown extensively over North Vietnam and conducted various
tasks, such as reconnaissance and signals intelligence missions, leaflet drops, and surface-to-
air missile radar detection. [8]

2.0.3 Overview of UAV System

The way a pilotless aircraft is controlled determines its categorization. In general, there are
three main names for pilotless aircraft:
1. Unmanned Aerial Vehicle (UAV): a pilotless aircraft that is either manually
controlled with a joystick or a mouse or autonomously flown by following a
preprogrammed mission. The acronym UAV is the most widely used term in describing
a civilian pilotless aircraft.

11
 2. Remotely Piloted Vehicle (RPV): a pilotless aircraft that is steered or controlled from
a remotely located position. Manually controlled pilotless aircraft means manually
controlling the aircraft position by manually adjusting its heading, altitude, and speed.
In many cases, the terms UAV and RPV are interchangeably used to describe any
pilotless aircraft.
3. Drone: one of the oldest terms used to describe a pilotless aircraft. A drone is defined
as a pilotless aircraft controlled by radio signal. Even with the emerging of the UAV
and RPV names, the name “drone” is still used even for civilian pilotless aircraft. For
the purpose of this course, the word drone is used to describe a pilotless aircraft
equipped with lethal payload. It is usually used by defense apparatus.

2.0.4 General Uses of UAVs

Naming the different missions for UAVs is a difficult task, as there are so many possibilities
and there have never been enough systems in use to explore all the possibilities. However, the
two main classifications for UAS missions are the following:
- The military mission: Military applications focus on weapons delivery and guided
missile support as well as directing artillery and spotting enemy positions.
- The civilian mission: Civilian applications of UAV are open to the imagination, and
only time will tell of the future missions of UAVs for civilian applications. As of today,
civilian missions include various applications such as:
i. Security awareness;
ii. Disaster response, including search and support to rescuers
iii. Communications and broadcast, including news/sporting event coverage;
iv. Cargo transport
v. Spectral and thermal analysis
vi. Critical infrastructure monitoring and inspection, including power facilities,
ports, bridges, and pipelines
vii. Commercial photography, aerial mapping and charting, and advertising.

12
On the geospatial and mapping applications side, the UAV can be used for the following
activities:
i. Aerial photography
ii. Mapping
iii. LIDAR
iv. Volumetric surveys
v. Digital mapping
vi. Contour mapping
vii. Topographic mapping
viii. Digital terrain modeling
ix. Aerial surveys
x. Photogrammetry (3D depth mapping)
xi. Temporal/spatial correlation for terrain reconstruction
xii. Geophysical survey

2.0.5 General Parts of a UAV

1. Standard propeller: The propellers are usually located at the front of the drone. There are
very many variations in terms of size and material used in the manufacture of propellers. Most
of them are made of plastic especially for the smaller drones but the more expensive ones are
made of carbon fiber. Propellers are still being developed and technological research is still
ongoing to create more efficient propellers for both small and big drones. Propellers are
responsible for the direction and motion of the drone. It is therefore important to ensure that
each of the propellers is in good condition before taking your drone out for flight. A faulty
propeller means impaired flight for the drone and hence an accident. You can also carry an
extra set of propellers just in case you notice some damage that was not there before.

2. Pusher propellers: Pusher propellers are the ones responsible for the forward and backward
thrust of the drone during flight. As the name suggest, the pusher propellers will determine the
direction the drone takes either forward or backward. They are normally located at the back of
the drone. They work by cancelling out the motor torques of the drone during stationary flight

13
leading to forward or backward thrust. Just like the standard propellers, the pusher propellers
can also be made of plastic or carbon fiber depending on the quality. The more expensive ones
are usually made of carbon fiber. There are different sizes depending on the size of the drone.
Some drones provide for pusher prop guards that will help protect your propellers in the event
of an unplanned crash. Always ensure you inspect your pusher propellers before flight as this
will determine the efficiency pf the flight.

3. Brushless Motors: All drones being manufactured lately use the brushless motors that are
considered to be more efficient in terms of performance and operation as opposed to the brushed
motors. The design of the motor is as important as the drone itself. This is because an efficient
motor means you will be able to save on costs of purchase and maintenance costs. In addition
to that, you will also save on battery life which contributes to longer flight time when flying
your drone. Currently, the drone motor design market is pretty exciting as companies try to
outdo each other in coming up with the most efficient and best developed motors. The latest in
the market is the DJI Inspire 1 which was launched recently. This offers more efficient
performance and saves on battery life. It is also relatively quiet and does not produce a lot of
unnecessary noises.

4. Landing Gear: Some drones come with helicopter-style landing gears that help in landing the
drone. Drones which require high ground clearance during landing will require a modified
landing gear to allow it to land safely on the ground. In addition to that, delivery drones that
carry parcels or items may need to have a spacious landing gear due to the space required to
hold the items as it touches the ground. However, not all drones require a landing gear. Some
smaller drones will work perfectly fine without a landing gear and will land safely on their
bellies once they touch the ground. Most drones that fly longer and cover longer distances have
fixed landing gears. In some cases, the landing gear may turn out to be an impediment to the
360 degrees view of the environment especially for a camera drone. Landing gears also increase
the safety of the drone.

5. Electronic Speed Controllers: An electronic sped controller (ESC) is an electric circuit whose
main responsibility is to monitor and vary the speed of the drone during flight. It is also
responsible for the direction of flight and variations in brakes of the drone. The ESC is also
responsible for the conversion of DC battery power to AC power to propel the brushless motors.
Modern drones depend entirely on the ESC for all their flight needs and for performance. More

14
and more companies are coming up with better performing ESC that reduce power needs and
increase performance, the latest one being the DJI Inspire 1 ESC. The ESC is mainly located
inside the mainframe of the drone. It is unlikely that you will need to do anything or make any
change on the ESC but in case you need to make any changes, you can locate it inside the
mainframe of the drone.

6. Flight Controller: The flight controller is basically the motherboard of the drone. It is
responsible for all the commands that are issued to the drone by the pilot. It interprets input
from the receiver, the GPS Module, the battery monitor and the onboard sensors. The flight
controller is also responsible for the regulation of the motor speeds through the ESC and for the
steering of the drone. Any commands such as triggering of the camera, controlling the autopilot
mode and other autonomous functions are controlled by the flight controller. Users will most
likely not be required to make any alterations to the flight controller as this may often affect the
performance of the drone.

7. The Receiver: The receiver is the unit responsible for the reception of the radio signals sent
to the drone through the controller. The minimum number of channels that are needed to control
a drone are usually 4. However, it is recommended that a provision of 5 channels be made
available. There are very many different types of receivers in the market and all of them can be
used when making a drone.

8. The Transmitter: The transmitter is the unit responsible for the transmission of the radio
signals from the controller to the drone to issue commands of flight and directions. Just like the
receiver, the transmitter needs to have 4 channels for a drone but 5 is usually recommended.
Different types of receivers are available in the market for drone manufacturers to choose from.
The receiver and the transmitter must use a single radio signal in order to communicate to the
drone during flight. Each radio signal has a standard code that helps in differentiating the signal
from other radio signals in the air.

9. GPS Module: The GPS module is responsible for the provision of the drone longitude,
latitude and elevation points. It is a very important component of the drone. Without the GPS
module, drones would not be as important as they are today. The modules helps drone navigate
longer distances and capture details of specific locations on land. The GPS module also help in

15
returning the drone safely “home” even without navigation using the FPV. In most modern
drones, the GPS module helps in returning the drone safe to the controller in case it loses
connection to the controller. This helps in keeping the drone safe.

10. Battery: The battery is the part of the drone that makes all actions and reactions possible.
Without the battery, the drone would have no power and would therefore not be able to fly.
Different drones have different battery requirements. Smaller drones may need smaller batteries
due to the limited power needs. Bigger drones, on the other hand, may require a bigger battery
with a larger capacity to allow it to power all the functions of the drone. There is a battery
monitor on the drone that helps in providing battery information to the pilot to monitor the
performance of the battery.

2.1 Flight Physics

`As in the case of this thesis, we would be considering the flight physics of a low-speed aircraft.
Certain factors come into play in order to have a sustained ‘flight’.

Certain forces act on a plane that ensure that the plane stays in its state of flight. These
forces are lift, drag, gravity/weight and thrust. When an aircraft is flying straight and level at a
constant speed, the lift it produces balances its weight, and the thrust it produces balances its
drag. However, this balance of forces changes as the airplane rises and descends, as it speeds
up and slows down, and as it turns[9] . For an airplane to fly, the four forces have to have the
right balance. Taking off requires a stronger thrust than drag, and landing requires reduced
thrust and lift to bring the plane back down to the ground. Airplane wings are an important
component of lift due to the difference in air pressure on the top surface as compared to the
under surface as a plane flies. This difference causes the airplane to go up. [10]

16
2.1.1 Lift: In order for an aircraft to rise into the air, a force must be created that equals or
exceeds the force of gravity acting on the mass. This force is called lift. In heavier-than-air
craft, lift is created by the flow of air over an airfoil. The shape of an airfoil causes air to flow
faster on top than on bottom. The fast flowing air decreases the surrounding air pressure.
Because the air pressure is greater below the airfoil than above, a resulting lift force is created.
To further understand how an airfoil creates lift, it is necessary to use two important equations
of physical science.
The pressure variations of flowing air is best represented by Bernoulli's equation. It was derived
by Daniel Bernoulli, a Swiss mathematician, to explain the variation in pressure exerted by
flowing streams of water.
Bernoulli equation(1) is written as[10]:

1
𝑃 + ρ𝑉 2 = 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡 (1)
2

P = pressure (force exerted divided by area exerted on)

Rho (ρ) = density of the fluid
V = velocity of the moving object or fluid

To understand the Bernoulli equation, one must first understand another important principle of
physical science, the continuity equation. It simply states that in any given flow, the density
(rho) times the cross-sectional area (A) of the flow, times the velocity (V) is constant.
Continuity equation(2) is written as[10]:
ρ × 𝐴 × 𝑉 = 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡 (2)
Rho(ρ) = density of fluid
A = acceleration of flow
V = velocity of the moving object or fluid

Using the Bernoulli equation and the continuity equation, it can be shown how air flowing over
an airfoil creates lift. Take air flowing over a stationary airfoil, such as an aircraft wing. Far
ahead of the airfoil, the air travels at a uniform velocity. To flow past the airfoil, however, it
must split in two, part of the flow traveling on top and part traveling on the bottom.

17
 LOW PRESSURE

HIGH PRESSURE
FIGURE 2.10 SHOWING THE “SPLIT” OF FLUID FLOW PAST AN AIRFOIL TO
GENERATE LIFT[10]

The shape of a typical airfoil is asymmetrical: its surface area is greater on the top than on the
bottom. As the air flows over the airfoil, it is displaced more by the top surface than the bottom.
According to the continuity law, this displacement, or loss of flow area, must lead to an increase
in velocity[9].

The Bernoulli equation states that an increase in velocity leads to an decrease in

pressure. Thus the higher the velocity of the flow, the lower the pressure. Air flowing over an
airfoil will decrease in pressure. The pressure loss over the top surface is greater than that of
the bottom surface. The result is a net pressure force in the upward (positive) direction. This
pressure force is lift.
There is no predetermined shape for a wing airfoil, it is designed based on the function of the
aircraft it will be used for. To aid the design process, engineers use the lift coefficient to measure
the amount of lift obtained from a particular airfoil shape[11]. Lift is proportional to dynamic
pressure and wing area.
Lift equation(3) is written as[10]:
1
𝑙𝑖𝑓𝑡 = 𝐶𝑙 × ( 𝑝𝑉 2 ) × 𝑆 (3)
2

18
2.1.2 Drag: This is a force exerted on an object moving through a fluid, it is always oriented
in the direction of relative fluid flow. Drag occurs because the fluid and the object exchange
momentum when impacting, creating a force opposing the motion of the object[9]. Drag is
higher when:
- The surface area of the object exposed to the fluid flow is higher
- The object is moving faster (or the relative fluid flow is faster)
- The fluid has more momentum, or inertia (the viscosity and density of the fluid are high)

Like lift, drag is proportional to dynamic pressure and the area on which it acts. The
drag coefficient is a measure of the amount of dynamic pressure gets converted into drag.
Unlike the lift coefficient however, engineers usually design the drag coefficient to be as low
as possible. Low drag coefficients are desirable because an aircraft's efficiency increases as
drag decreases. The
Equation of Drag(4) is:
𝑝 × 𝑉2
𝑑𝑟𝑎𝑔 (𝐷) = 𝐶𝑑 × ×𝐴 (4)
2

Where: Cd is the coefficient of drag

p is density of fluid
V = velocity of the moving object or fluid
A = acceleration of flow

2.1.3 Weight: This is simply the force exerted due gravity on the aircraft, it acts in a
downward direction. The weight is a limiting factor in the design of an aircraft, I heavier plane
requires more thrust and a longer runway to take off. The weight of an aircraft should be
stabilized in order to have a stable and controllable flight.
Weight(5) is given as:
𝑊 = 𝑀𝑔 (5)

W = weight
M = mass
g = acceleration due to gravity

19
2.1.4 Thrust: Thrust is a force that opposes drag. The engine creates thrust and moves the
plane forward, the engines push air back with the same force that the air moves the plane
forward, tthrust force-pair is always equal and opposite according to Newton's 3rd Law. When
thrust is greater than drag, the plane accelerates according to N When the plane flies level at
constant velocity, thrust equals drag.
Thrust(6) is given as:
𝐹 = 𝑀𝐴 (6)

F = thrust
M = mass
A = acceleration

FIGURE 2.11 FORCES ACTING ON AN AIRCRAFT[10]

2.2 Flight Dynamics

UAVs as a type of aircraft move in a fluid medium, hence they need different methods to direct
their movement and also to maintain their orientation. In order to provide stability and control,
most airplanes use various control surfaces that work on the same principle as a wing.[12]

20
2.2.1 Control Surfaces
The control surfaces help maintain stability and also aids in the navigation of the UAV, these
control surfaces include:

1. Aileron: An aileron is a hinged control surface usually forming part of the trailing edge of
each wing of a fixed-winged UAV. Ailerons are used in pairs to control the aircraft in roll (or
movement around the aircraft's longitudinal axis), which normally results in a change in flight
path due to the tilting of the lift vector.
2. Elevators: These are usually located at the rear of an aircraft, which control the aircraft's pitch,
and therefore the angle of attack and the lift of the wing. In UAVs the elevators on the rear of
the aircraft at usually the only pitch control surface present.
3. Rudder: It is a directional control surface usually attached to the horizontal tail structure. On
UAVs, the rudder is usually attached to the fin, known as vertical stabilizers which allows for
the control of yaw about the vertical axis, i.e. change the horizontal direction in which the nose
is pointing.

FIGURE 2.12 CONTROL SURFACES ON UAVs[12]

21
2.2.2 UAV Movements
The movements of a fixed-wing UAV are grouped based on the axis it rotates relative to, these
movements include:
- Roll: Taking into consideration an invisible horizontal line going straight through the
plane's nose, center of gravity and tail, this is called the roll axis. By adjusting the plane's
ailerons it causes the lift to increase in one wing and decrease in the other, when this
occurs and one wing rises, the other descends it causes the body of the plane to rotate
along its roll axis, which results in a maneuver known as a roll. However, in situations
where a plane merely rolls enough just to tilt the angle of the airfoil, the aircraft banks or
turns.
- Yaw: Taking into consideration an invisible vertical line intersecting the center
of gravity, going straight down through the top of the aircraft and out through the belly,
this is called the yaw axis, and it comes into play when the aircraft's rudder is moved.
The rudder's deflection results in a side force, rotating the tail in one direction and the
nose in the other. This is called a yaw motion.
- Pitch: Taking into consideration an invisible horizontal line moving through the sides
of the aircraft's center of gravity, roughly parallel to the wings. This is the pitch axis,
which necessitates the pitch motion due to changes in the airplane's elevator. When the
tail tilts down, the nose rises and the plane ascends and vice versa.[13]

FIGURE 2.13 PICTORIAL REPRESENTATION OF UAVs MOVEMENTS[12]

22
CHAPTER 3: MATERIALS AND METHOD

3.0 Materials Used

1. Strawboard: The strawboard is a recycled material gotten from paper. It has an averagely
high tensile strength of 44.6MPa[14] in comparison to other cheaper alternatives for use on the
body of the UAV such as foam board with a tensile strength of 36.1MPa[15], it has a tensile
strength of hence serves suitable material for the UAV. The strawboard is also water resistant.
The strawboards come in various sizes, 3 sheets were used in the fabrication of the UAV. Figure
3.1 below shows a sample of the strawboard.

FIGURE 3.1 STRAWBOARD

2. Brushless DC Motors [x2] : Brushless DC motors which are also known as synchronous DC
motors or electronically commutated motors (ECM), the brushless motor is powered by a
direct current through an inverter which gives it electricity in the form of alternating current in
order to drive each phase of the motor, this inverter is a closed loop controller known as an
Electronic Speed Controller (ESC). The electronic speed controller provides pulses of current
to the motor windings, this provided pulse controls the speed and torque of the motor. The

23
brushless motor is highly suitable for use in the UAV because of its desirable characteristics
such as:
i. High power to weight ratio
ii. It is electronically controlled meaning the speed can easily be controlled
iii. High speed
iv. Requires little to no maintenance.
v. Reduced vibration
vi. Increased efficiency
vii. Lower power requirement
viii. Elimination of ionizing sparks from commutator

The brushless motors used in this project are from the brand “DYS” with a rating of 1000KV
and a weight of 0.02kg. The brushless motors come with mounts for the propeller and also the
secure the motor firmly to the UAV. 2 of the motors were used, these served as the engines.
The brushless motors are as seen in figure 3.2

FIGURE 3.2 BRUSHLESS MOTORS

24
3. Electronic Speed Controller (ESC) [x2]: The Electronic Speed Controller (ESC) is a device
that regulates the power of an electric motor which allows the brushless motor to throttle from
0% to 100% based off the signal gotten from a transmitted i.e. the remote control in the case of
this UAV. An ESC is made up of three key components:
i. BEC (battery eliminator circuit): The BEC sends a set amount of power (usually 5v
1Ah) back to the receiver to power the receiver and servos. This also makes sure
the brushless motor does not take all the power from the battery, when the battery
reaches its minimum operating capacity.
ii. Processer: The translates the information being given of by the receiver in the UAV
and switches the FETs to regulate the power to the brushless motors.
iii. FETs (field effect transistor): The FET is essentially an electronic switch that chops
up the flow of electricity which provide pulses that in turn throttles the brushless motor.
It also takes account of the full voltage and current of the battery and motor.

The electronic speed controller’s main advantages for it to be used in this project are as follows:
i. The ease of controlling the speed of the brushless motors.
ii. The provision of power to the receiver.
iii. Cutting off the Li-Po battery when it reaches its minimum operating capacity to avoid
damaging it.

The electronic speed controllers used in this project are from the brand “Simonk” with a rating
of 30A, voltage range of 4-16V, Continuous current 30A; instant 35A:40A which lasts 10
seconds, and a weight of 0.025kg. 2 of this ESCs were used in this project. The ESC used is as
seen in the figure 3.3.

FIGURE 3.3 ELECTRONIC SPEED CONTROLLER (ESC)

25
4. Li-Po Battery: This is a lithium-ion polymer, it is a rechargeable battery that uses a polymer
electrolyte instead of a liquid electrolyte, high conductivity semisolid polymers form this
electrolyte. The main reasons why Li-Po batteries are suitable for the project are as follows:
i. They are light weight.
ii. The come in various shapes and sizes.
iii. They have a large capacity considering how tiny they are.
iv. They can maintain a consistent voltage/power discharge.
v. They have a high discharge rate.
vi. They have a fast recharge rate.

The Li-Po battery used in this project is from the brand “HJ”, with a rating of 1300MAH,
voltage of 7.4V, contains 2 cells and has an XT60 plug. Only one of this battery is required for
the project. The battery is as seen in figure 3.4.

FIGURE 3.4 LI-PO BATTERY

26
5. Balance Li-Po Charger: This is a special charger for the Li-Po battery, it charges one cell at
a time until all the cells are of equal voltage ratings of the battery. It charges each cell to its
speculated voltage and bleeds out extra charge from overcharged cells through the discharge
leads, this is done to ensure the battery’s maximum life and as Li-Po cells are fragile and hence
prone to catching figure, this method of charging reduces the risk of that occurring. The balance
charger used for this project is from the brand “B3” with a charging power of 20W, able to
balance charge 2 and 3 celled batteries and a balance charging current of 1600mA.

6. Servo: A servo is short for servomechanism, the servo comprises of a DC motor, a

potentiometer and a control circuit which can precisely regulate how much movement there is
and in what direction. The desired position to be moved to by the servo is sent via electrical
pulses through the signal wire. The motor's speed is proportional to the difference between its
actual position and desired position therefore if the motor is near the desired position, it will
turn slowly, otherwise it will turn fast. This is called proportional control. Servos are controlled
by sending an electrical pulse of variable width shown in figure 3.5, or pulse width
modulation (PWM), through the control wire. There is a minimum pulse, a maximum pulse,
and a repetition rate. A servo motor can usually only turn 90° in either direction for a total of
180° movement. The motor's neutral position is defined as the position where the servo has the
same amount of potential rotation in the both the clockwise or counter-clockwise direction. The
PWM sent to the motor determines position of the shaft, and based on the duration of the pulse
sent via the control wire; the rotor will turn to the desired position. The servo motor expects to
see a pulse every 20 milliseconds (ms) and the length of the pulse will determine how far the
motor turns. For example, a 1.5ms pulse will make the motor turn to the 90° position. Shorter
than 1.5ms moves it in the counter clockwise direction toward the 0° position, and any longer
than 1.5ms will turn the servo in a clockwise direction toward the 180° position.

27
FIGURE 3.5 VARIABLE PULSE WIDTH THAT CONTROLS THE SERVO MOVEMENT

The advantages of the sure that made it desirable for use in this project are:
i. Precise position control.
ii. High torque.
iii. Large inertia.
iv. Lower power consumption
v. Smooth control in entire speed range
vi. It is maintenance free
vii. High power range.

The servos used in the project are from the brand “TowerPro”, weighing 0.009Kg, having a
stall torque of 2.5Kg/cm, operating speed of 0.1sec/60degree and input voltage of 4.2 to 6V. A
total of 5 servos were used. These servos were used to move the control surfaces such as the
aileron, elevator and rudder, one of the servos was used to control the payload door. As above,
the stall torque of 2.5kg/cm, this is the torque that is produced by a device when the output
rotational speed is zero or the torque load that causes the output rotational speed of a device to
become zero. The servo is as seen in figure 3.6.

28
 FIGURE 3.6 SERVO

7. Remote Controlled Transmitter and Receiver: The transmitter and receiver combination
basically serve the purpose of controlling the UAV, the transmitter sends a signal from the
user input to the receiver through radio waves which then directs every component to do as
the input received. The transmitter is used in this project has 6 channels i.e. I have control of 6
components, it has a range of 500meters, from the brand “FlySky”, the receiver has in input
voltage of 5V and uses the 2.4Ghz band for transmission.

FIGURE 3.7 RC TRANSMITTER FIGURE 3.8 RC RECIEVER

29
8. Other materials include:
i. Glue gun x1
ii. Super glue x10
iii. 8x6 inch propeller x2
iv. XT60 Series Battery Pack Connector x2
v. Y Shaped Servo extension wire x4
vi. Blade
vii. Measuring instruments

FIGURE 3.9 PROPELLER FIGURE 3.10 SERVO EXTENSION WIRE

FIGURE 3.11 XT60 BATTERY PACK CONNECTOR

30
3.0.1 Material Cost
Table 3.1 presents the cost breakdown of all materials used for this project

TABLE 3.1 COST BREAKDOWN OF THE PROJECT

3.1 Fabrication of Fixed Wing Delivery UAV

3.1.1 Time Frame(Work Schedule)
The fabrication of the UAV took 7 days with an average working hour of 3 hours 45minutes
per day. Table 3.2 gives a breakdown of the tasks undertaken and how long each task took.

TABLE 3.2 DURATION OF THE FABRICATION PROCESS

31
3.1.2 Assembly of Parts
The assembly process was pretty straightforward given that the drawings were well detailed
and additional flat patterns of each component was extracted from the drawing to ease the
cutting and joining processes. The whole assembly process incudes:
i. Cutting of parts
ii. Joining / fastening of parts
iii. Joining of sections
iv. Routing the wires and electrical components
v. Mounting servos
vi. Mounting engines
vii. Mounting propellers and landing gear

FIGURE 3.12 MEASUREING AND MARKING OUT OF THE FUSELAGE PARTS

32
FIGURE 3.13 MEASURING AND MARKING OUT OF THE RUDDER ASSEMBLY

33
FIGURE 3.14 MEASURING AND MARKING OUT OF THE TOP OF THE FUSELAGE

FIGURE 3.15 CUTTING OUT OF FUSELAGE

34
FIGURE 3.16 CUTTING OF THE TOP OF THE FUSELAGE

FIGURE 3.17 JOINING OF FUSELAGE PARTS

35
FIGURE 3.18 JOINT FUSELAGE SECTION

FIGURE 3.19 JOINT FUSELAGE

36
FIGURE 3.20 HORIZONTAL STABILIZER ASSEMBLY

FIGURE 3.21 TAIL ASSEMBLY WITH SERVOS IN PLACE

37
 FIGURE 3.22 TAIL ASSEMBLY WITH SERVOS RODS IN PLACE

FIGURE 3.23 WING ASSEMBLY WITH SERVOS AND ELECTRICAL WIRINGS IN PLACE

38
FIGURE 3.24 BENDING THE WING PROFILE

FIGURE 3.25 NOSE ASSEMBLY

39
 FIGURE 3.26 FULLY ASSEMBLED UAV

The cutting out of various parts and assembly of the UAV is a straight forward process given
that the 3D designs show how each part is to be fitted accordingly. After every joining process
the adhesive is left to dry completely for about 12 hours before any other process was carried
out.

40
3.1.3 Electrical Schematic

FIGURE 3.27 ELECTRIC SCHEMA FOR THE UAV

Given the setup of the fixed winged delivery drone, having two motors being controlled by 2
independent electronic speed controllers, attached in parallel to the battery and also from the
BEC of the ESC to the receiver, the motors are attached to the electronic speed controllers
independently taking note of the 3 phased connection to prevent the rotors rotating in opposite
directions. The BEC cables of the 2 electronic speed controllers are connected in parallel using
the Y Shaped Servo extension wire, one of the positive leads is disconnected to as to prevent
shorting, the Y Shaped Servo extension wire is then connected to the channel on the receiver
for the throttle, this provides power to the receiver and also sends signals to the ESC relating to
the throttle speed. The positive and negative leads of the 2 ESCs are connected in parallel to
the XT60 Series Battery Pack Connector to the battery. Servos for the 2 ailerons are connected

41
in parallel to the receiver, all other servos are connected to independent channels of the receiver,
this connection for the servos provides the signal and power. The cables are extended in case
they don’t reach the desired destination.

42
CHAPTER 4: RESULTS AND DISCUSSION

4.0 Design of Fixed Wing Delivery UAV

The UAV was designed using SolidWorks, a 3D CAD software. The fixed wing UAV consists
of various parts and this section outlines the principles used in the design and how the various
parts are designed giving more attention to the wings which generates lift. The design is
modular hence it gives options for future additions of various modules such as cameras. These
parts of the UAV include:

4.0.1 The Fuselage (body)

The Fuselage which takes the payload and all electronic components consists of the sides,
bottom and the top of the fuselage. These parts are designed to be streamlined in order to reduce
the drag on the plane in flight. The fuselage can be seen in fig. 4.3. The body is segmented into
various parts in order to ease the production, these parts include:
i. The upper part: This part is the top of the fuselage, it includes cut outs for the
passing through of the wires and electronic components, the length is also the
total length of the fuselage, this part is as seen in fig. 4.1.

FIGURE 4.1 DRAWING OF THE UPPER PART OF THE WING WITH

DIMENSIONS

43
ii. Side: The side of the fuselage is designed in a way to curve into the fuselage
profile giving a more streamlined shape, also the height of the sides is the total
height of the fuselage. The sides are quiet rigid in order to maintain the
fuselage shape. The sides are also able to absorb some of the shocks during
landing. The fuselage can be seen in fig. 4.2

FIGURE 4.2 DRAWING OF THE SIDE OF THE FUSELAGE WITH DIMENSIONS

iii. The lower part: The lower part is designed to be streamlined and curved to an
angle matching the angle on the cut-out parts of the sides of the fuselage. The
lower part is strong enough to hold the payload and also includes a cargo hull
and door controlled by a servo to drop the payload.

44
 FIGURE 4.3 DRAWING SHOWING THE ASSEMBLED FUSELAGE

4.0.2 The Nose

The nose is the leading edge of the plane that first cuts through the fluid medium in this case
‘air’ hence it has to be streamlined. The nose is made of an aerodynamic shape, the main reason
being to reduce the air drag (friction due to air). The aerodynamic shape is designed to have
minimum drag so it can go forward more efficiently thereby reducing the power consumption.
The nose assembly also houses the battery so as to balance out the weight and get a centralized
center of gravity for the UAV.

45
4.0.3 The Main Wing
In order to sustain flight a in the air which is to be steady and leveled, it is therefore necessary
to generate an upward force known as “Lift” which must balance the weight[9]. The lift is
generated by producing a greater pressure below the wing than above, in order to produce this
lift a surface is either inclined or cambered to the air flow direction or both at the same time[10].
According to a study carried out, the problem is to explain why such shapes produce a pressure
difference when moved through the air. Early experimenters found that whether they used a
curved or an inclined surface, the average speed of air flow relative to the wing was greater on
the upper surface than on the underside, increases in air flow speed are associated with a
reduction in pressure, so the lower pressure on the upper surface is associated with the higher
relative air speed[11]. Explanations for the generation of lift are, therefore, often based on the
idea that the difference in speed between upper and lower surfaces causes the difference in
pressure, which produces the lift. These explanations are, however, unconvincing, because, as
with the chicken and the egg, we might alternatively argue that the difference in pressure causes
the difference in speed. It is also difficult to explain in simple physical terms why the difference
in speed occurs. [9]. The following were considered in designing the wings:

1. Take off mass: The weight of the payload expected to be carried by the delivery drone is
0.5kg. In order to estimate the take-off mass one has to consider the historical ratio of
Payload-weight fraction(7) Which is given as[16]:
𝑊𝑝𝑙
0.201 = (7)
𝑊0
In order to estimate the takeoff weight of the fixed wing delivery UAV, with a payload weight
of 0.5kg, we rewrite equation 7 as:
0.5
𝑊0 = = 2.5𝑘𝑔
0.201
Hence 2.5kg is meant to be shared amongst the components of the UAV, but to be on the safer
side, we calculate the take off weight using a payload of 0.6kg instead; adding the extra 0.1kg
as the factor of safety. Hence:
0.6
𝑊0 = = 3𝑘𝑔
0.201

Therefore the take of weight to be used is 3kg which means the total weight of the drone should
be less than 3kg.

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2. Wing Surface Area
First of all, a wing load has to be chosen, this is simply the total mass of the aircraft divided
by the surface area of the wing. It can also be said as the amount mass of the plane carried by
each square meter of the wing. Considering the various UAVs available that are similar in
size and weight to the delivery UAV to be designed, 28.5N/𝑚2 [17] is selected as the wing
load.
Wing load(8) is given as[11] :
𝑊
= 𝑊𝑖𝑛𝑔 𝑙𝑜𝑎𝑑 (8)
𝑆
W = weight of UAV
S = wing surface area
Therefore:
3×9.8
𝑆=
28.5

S = 1.03𝑚2
1.03𝑚2 is taken as the total surface area of the wing. During the design process, 1.03𝑚2 is the
total surface area of the wing when opened up as a rectangle. Given the above information, a
rectangle having the required surface area can be created with the CAD software, given that
specific instructions are in place; the rectangle should be longer length wise and having a
considerably small width. This gotten rectangle is than folded with an angle attack of 11
degrees.

FIGURE 4.4 LAYOUT SHOWING THE WING ASSEMBLY

47
As seen in the above fig. 4.4, cutouts are there for mounting the servos, the electrical motors
and routing of necessary wires, also the slots of ailerons which controls the banking turn of the
plan as discussed in chapter 2. The tip of the aileron in contact with the wing is cut to an angle
of 45 degrees so as to enable free movement of the ailerons.

4.0.4 Tail
The tail assembly consists of the elevator assembly and the rudder assembly, these are essential
given that they control the ascending, descending and turning of the UAV.
- The rudder assembly consists of:
i. Rudder wing (Fin): The rudder wing also known as the vertical stabilizer serves
to stabilize the UAV and also as a mount for the rudder. The rudder wing
stabilizes the UAV against unwanted side by side motion. It is designed in such
a way that it is strong enough to hold up the rudder, streamlined to reduce
turbulence and has slots to fit perfectly with other components of the tail
assembly.
ii. Rudder: The rudder which is a control surface that controls the UAV’s yaw,
usually attached to the rudder wing. The design is similar to that of the ailerons
where the edge in contact with the rudder wing is cut to an angle of 45 degrees
to enable free movement and has slots for the attachment of the servo rods that
cause the sway of the rudder

- The elevator assembly consists of:

i. Horizontal Stabilizer: The horizontal stabilizer is a fixed wing section which
mainly serves to provide stability to the UAV, to keep it flying straight.
The horizontal stabilizer prevents up and down known as the pitching motion.
It is designed in such a way to house the elevator, attach to the tail assembly and
also of sufficient surface area to generate considerable amount of lift this helps
in cases of engine failure, it aids the UAV to glide down.
ii. Elevator: The rudder controls the UAV’s pitch, it is usually attached to the
rudder wing. The design is also similar to that of the ailerons as they are all
control surfaces where the edge in contact with the horizontal stabilizer is cut to

48
 an angle of 45 degrees to enable free movement and has slots for the attachment
of the servo rods that cause the sway of the rudder.
iii. Vertical stability: The vertical stabilizer carries out same function is the rudder
wing (fin) mentioned above. It stabilizes the UAV against unwanted side by side
motion.

FIGURE 4.5 COMPLETED UAV DESIGN

From figure 4.5, the parts numbered are:
1. The nose 11. Fuselage
2. Propeller
3. Main wing
4. Aileron
5. Rudder wing(Fin)
6. Rudder
7. Elevator
8. Vertical stabilizer
9. Horizontal stabilizer
10. Landing gear

49
 FIGURE 4.6 ORTHOGRAPHIC PROJECTION OF THE UAV

4.1 Weight of UAV

Measured weight = 1.50kg
Measured weight including the payload = 2.0kg

4.2 Motor RPM

Given the motor rating of 1000Kv and battery rating of 1300MAH, 7.4v.
The Motor RPM(9) can be derived as
𝑅𝑃𝑀 = 𝑀𝑜𝑡𝑜𝑟 𝑝𝑜𝑤𝑒𝑟 𝑟𝑎𝑡𝑖𝑛𝑔 × 𝑏𝑎𝑡𝑡𝑒𝑟𝑦 𝑣𝑜𝑙𝑡𝑎𝑔𝑒 × % 𝑜𝑓 𝑡ℎ𝑟𝑜𝑡𝑡𝑙𝑒 (9)
Hence for the given motor at 100% throttle, the propellers spin at:
1000 × 7.4 × 1 = 7400𝑅𝑃𝑀

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4.3 Lift Generated
In order to calculate the theoretical lift generated, the coefficient of lift must be determined with
its variable component being velocity.
Coefficient of lift(10) is given as:

2𝐿
𝐶𝑙 = (10)
𝑝 × 𝑉2 × 𝐴

The coefficient of lift is proportional to the angle of attack of the wing, this relationship can be
seen in the standard chart below:

FIGURE 4.7 CHART OF COEFFICIENT OF LIFT FOR A CHAMBERED WING

Given the coefficient of lift for a chambered wing chart, the 𝐶𝑙 of the fixed wing UAV having
an angle of attack of 11 degrees is 1.09. Using the following formula below the lift generated
at various velocities can be calculated:

51
Given the Angle of attack (A) : 11degrees , 𝐶𝑙 = 1.09
Area of wing (s): 1.03m^2
Density of air (p): 1.225 kg/m^3

1
𝑙𝑖𝑓𝑡 = 𝐶𝑙 × ( 𝑝𝑉 2 ) × 𝑆 (3)
2

The lift generated by the wing at various velocities can be seen in the table 4.1.

TABLE 4.1 LIFT GENERATED AT VARIOUS VELOCITIES

From the earlier calculation of the theoretical take-off weight being 3kg = 29.4 newtons, the
table above shows that at about 7m/s the lift generated is a bit higher than the weight hence any
speed higher would make the UAV lift.

52
4.4 Stress Analysis
Taking consideration of the fact that the main wings bear the bulk of the stress which is
maximum during take-off and steady flight, given that the take-off weight is 3kg=29.4 newtons.
One can assume with a safety factor of 1.5 that the wing experiences 44.1 newtons in the course
of take-off, hence running a stress analysis simulation with the parameters in place on the
material with a tensile strength 44.6MPa, figure 4.8 shows the bulk of the force is experienced
at the tip of the wings and it is not sufficient to cause a failure hence the material would not
break.

FIGURE 4.8 STRESS ANALYSIS OF UAV DURING TAKE OFF

With the aforementioned parameters in place, we take consideration of the UAV in flight. The
UAV experiences stress on the main wings and also the tail assembly due to the fact that they
work together in ensuring the flight is leveled and reduces the side to side sway to the barest
minimum. As seen in figure 4.9, the stress acting on the main body is negligible because the
UAV is not flying too high above sea level to a region where it would experience a greater
atmospheric pressure.

53
 FIGURE 4.9 STRESS ANALYSIS OF UAV IN FLIGHT
Theoretically this material would not fail given it is used within the constraints of the UAV, the
material of tensile strength 44.6MPa is sufficient enough to be used on the UAV.
In as much as the stress acting upon the UAV assembly wouldn’t cause a failure from
the materials side, one of the most important joints which is between the main wing and fuselage
assembly must be considered. In figure 4.10 below, the parameters remaining constant, it can
be observed that the force exerted on the joint is quiet high, equivalent to that on the tips of the
wing in flight, hence the link between these two parts must be reinforced with either balsa wood
or metal strips in order to cut out the possibility of it failing when it experiences a high amount
of force.

FIGURE 4.1O STRESS ANALYSIS ON LINK BETWEEN MAIN WING AND FUSELAGE

54
4.5 Flight testing

FIGURE 4.11 UAV IN STEADY FLIGHT

Figure 4.8 shows the UAV in a steady flight at about 200 meters above ground, this shows that
all systems worked, the wing has enough surface area to generate lift at speeds controlled by
the combination of the ESC, brushless motors and battery and the UAV was able to open the
cargo hull under, drop the payload and come back to land at a designated point. It should be
noted that due to my lack of flying skills, the UAV landed fast and lost it’s landing gears and
the detachable vertical stabilizers on the elevator assembly, asides from that every other
component held in place. Figure 4.9 shows the UAV ascending, this was made possible by
pitching the elevator up and increasing the throttle. The UAV flew for 30 minutes before
running out of power.

FIGURE 4.12 UAV ASCENDING

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CHAPTER 5
5.0 Conclusion
The development of an unmanned aerial vehicle for delivery which is the sole aim of the project
was achieved using renewable materials which can be locally sourced and have sufficient
tensile strength required for such operation; this is extensively talked about in the materials
section. In achieving the aim of this project some objectives were also achieved this includes;
the fixed wing delivery UAV was able to carry a payload of up to 0.5kg, the UAV had a
considerable flight time which is restricted by the capacity of the battery, from testing the
average flight time on full throttle is about 30 minutes, provision of further improvements;
given that the modular design allows the change of various components to satisfy different
purposes. As observed all set objectives for this thesis were achieved and everything works
theoretically and practically

5.1 Recommendation
The future of UAVs in general in Nigeria is bright, given that more hobbyists are interested in
building a career out of it and considering the vast applications in area of security, surveying,
delivery and even military applications. As in the case of my thesis, the fixed wing delivery
UAV is of a modular design hence it can easily be converted from a delivery drone to a
surveillance drone or used for any other form of application. In addition, combining a raspberry
Pi, an onboard 4g module and antennas the range of the delivery drone can be converted from
the limited range of the receiver to an unlimited range given that there is cellular network and
a higher battery capacity. The wings can also be made out of solar cells which recharge the
batteries hence increasing the flight duration.

56
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