ENGN8100:
Introduction to System Engineering
Sub-System:
Energy Conversion System
Name
Mauricio Veloso
Pouyan Taghipour Bibalan
Brad Stanford
Kwan-Hoe, Tay
Nan Yi
Xuefeng Ye
Ming Chen
Student ID
u4474096
u4422921
u4500144
u4376339
u4382406
U4466785
u4242754
Page 1
Abstract
With the final goal being to design an ecologically sustainable ultralight aircraft, it is
necessary to first gather a list of customer needs to ensure that the end product is able to
satisfy their requirements. A functional decomposition of the project is performed to
ensure each critical aspect is analysed while still working towards a common goal.
The report details the importance of the customer needs in relation to the energy
conversion subsystem. The list of concepts generated for the sub-system will be described
and using the needs-metrics matrix to screen and benchmark concepts which will be
eliminated if the requirements are not met.
The lifetime costs of an internal combustion engine and electric motor are analysed in the
form of a life-cycle analysis. The significance of such an analysis is to compare the cost in
using either concept. The final selection criteria and subsystem specifications are detailed
with recommendations for future improvements being discussed at the end of the report.
Page I
I.
TABLE OF CONTENTS
II.
List of Figures
III.
List of Tables
1.
INTRODUCTION 1
2.
CUSTOMER NEEDS
3.
4.
5.
2.1
Customer needs hierarchy and importance
3
2.2
Metrics
4
2.3
Needs-Metrics Matrix
5
2.4
Customer Needs Justification
7
BENCHMARKING AND SPECIFICATION
3.1
Benchmark
3.2
Target Specifications
7
7
10
FUNCTIONAL DECOMPOSITION
10
4.1
Functions of our sub-system energy conversion
11
4.2
Function analysis on sub-system level
12
4.3
Graphical representation of functional decomposition
13
4.4
Variations on functional decomposition
14
CONCEPT GENERATION
5.1
5.2
15
Concept tree generation
5.1.1
5.1.2
5.1.3
5.1.4
Concept tree for the Conversion to Propulsion sub-subsystem
Concept tree for Storage Energy sub-subsystem
Concept Tree for the Energy Conversion to Stored Energy sub-subsystem
Concept Tree for the Conversion to Internal Energy sub-subsystem
Putting It Together: Concepts
5.2.1
5.2.2
5.2.3
5.2.4
5.2.5
5.2.6
5.2.7
5.2.8
5.2.9
5.2.10
5.2.11
5.2.12
6.
3
Conventional internal combustion engine
Internal combustion engine(diesel)
Solar powered and solar powered with battery assistance
Jet engine
Fuel cell powered with battery assisted takeoff
Hybrid drive
Electric with rocket assisted take off
Human powered aircraft
Wind powered aircraft
Nuclear powered aircraft
Regenerative braking
Gravity powered aircraft
15
15
16
17
17
18
19
19
20
21
21
22
24
25
26
27
28
29
CONCEPT SCREENING AND SCORING 30
6.1
Preliminary Concept Screening
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
30
Page II
6.2
Concept Scoring
32
6.3
Further concept screening
33
6.3.1
6.3.2
7.
8.
33
34
CONCEPT SELECTION AND JUSTIFICATION 34
7.1
Life Cycle Analysis – Internal Combustion Engine
37
7.2
Life Cycle Analysis – Electric Motor
38
7.3
Concept Recommendation
38
CONCEPT DEVELOPING AND DESCRIPTION 39
8.1
Battery
39
8.1
Electric Motor
41
8.1.1
8.1.2
8.1.3
8.1.4
DC motor
Torque motor
AC motor
Slip ring
41
42
42
42
8.2
Choosing the right motor
42
8.3
Design a new motor
43
8.3.1
8.3.2
8.4
8.4.1
8.4.2
8.4.3
8.4.4
8.4.5
8.5
9.
Solar Powered and Fuel Cell power Elimination:
Jet Engine Elimination
Brushless motor basics
Final Design based on Antares 20E
43
43
Propeller selection/design specifications
44
Pitch and types of propellers
Propeller diameter
Number of blades
Material of blades
Selecting criteria
44
45
46
46
46
Final Specifications
RECOMMENDATIONS FOR NEXT STEPS
46
49
9.1
Increase motor efficiency
49
9.2
Integrating with Fuel Cell and Solar Cell
49
9.3
Improved aerodynamic structure
50
10. CONCLUSIONS 50
REFERENCES 52
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Page III
II. List of Figures
Figure 1: Scale to measure Importance.................................................................................. 4
Figure 2: Rotax 503 ................................................................................................................. 7
Figure 3: Rotax 912 ................................................................................................................. 8
Figure 4: EM-10 ...................................................................................................................... 8
Figure 5: Black box of a sub-system ..................................................................................... 12
Figure 6: Functional Decomposition of Energy Conversion Sub-system.............................. 13
Figure 7: Concept Tree for Propulsion System ..................................................................... 15
Figure 8: Concept Tree for Storage System .......................................................................... 16
Figure 9: Concept Tree for Energy Conversion to Stored Energy System ............................ 17
Figure 10: Concept Tree for the Conversion to Internal Energy sub-subsystem ................. 17
Figure 11: SunSeeker, Aircraft based on Solar power .......................................................... 20
Figure 12: TRS-18 Turbojet Engine ....................................................................................... 21
Figure 13: Typical torque and horsepower curve for an internal combustion engine ....... 23
Figure 14: Typical torque and horsepower curves of an electric motor ............................. 23
Figure 15: Gossamer Albatross ............................................................................................. 25
Figure 16: Wind Power Generator ....................................................................................... 26
Figure 17: Nuclear Powered Aircraft Design Examples ........................................................ 27
Figure 18: The Gravity-Powered Aircraft ............................................................................. 29
Figure 19: Cost vs. Power comparison, Internal Combustion Engine and Electric motor ... 36
Figure 20: Cost vs. Power/Weight comparison, Internal Combustion Engine and Electric
motor .................................................................................................................................... 36
Figure 21: Rotax 912 ............................................................................................................. 37
Figure 22 Lithium-ion battery ............................................................................................... 39
Figure 23 Lithium polymer battery ....................................................................................... 39
Figure 24 Lead-acid battery .................................................................................................. 40
Figure 25 Nickel-metal hydride battery................................................................................ 40
Figure 26 Nickel-Cadmium battery ....................................................................................... 40
Figure 27 Hypothetical two-pole three-slot brushless motor ............................................. 43
Figure 28 EM42 42kW Brushless DC Motor ....................................................................... 44
Figure 29 Cost vs. Power for final design ............................................................................. 47
Figure 30 Weight vs. Power for final design ......................................................................... 48
Figure 31: Cost Analysis of Fuel Cells.................................................................................... 50
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Page IV
III. List of Tables
Table 1: Mission Statement: Ecologically Sustainable Ultra-light Aircraft ............................. 1
Table 2: Summary of System needs ....................................................................................... 2
Table 3: Detailed Customer Needs for Energy Conversion System ....................................... 4
Table 4: List of Metrics ........................................................................................................... 5
Table 5 Needs-Metrics Matrix ................................................................................................ 6
Table 6: General Benchmark for Different Types of Engines ................................................. 8
Table 7 Benchmarking table for 5 type energy conversion systems ...................................... 9
Table 8: Necessary functions to provide for energy conversion sub-system ...................... 11
Table 9: Optional functions to provide for energy conversion sub-system ......................... 11
Table 10: Necessary functions required from other sub-systems ....................................... 12
Table 11: Energy, material and signal flow of energy conversion sub-system .................... 12
Table 12 Concept Screening Table ....................................................................................... 31
Table 13 Selection Criteria for Energy Conversion System Selection .................................. 33
Table 14 Existing Solar Powered Aircraft Specifications .................................................... 33
Table 15 Cost Comparison of 5 different energy sources to generate one kW of energy .. 34
Table 16: Cost vs. power Data Set for Internal Combustion Engine .................................... 35
Table 17: Cost vs. power Data Set Electric Motor ................................................................ 35
Table 18: Waste analysis for Internal Combustion Engine (Rotax 912) ............................... 37
Table 19 Motor specifications for some existing battery powered aircrafts ....................... 41
Table 20 Energy conversion Specifications for 3 set points ................................................. 47
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Page V
1. Introduction
The objective of this course is to develop an ultra-light aircraft which would be ecologically
sustainable while still appealing to the mass market. Like any other product, boundaries of
the project relating to the target audience have to be set.
Mission Statement: Ecologically Sustainable Ultra-light Aircraft
Product
Description:
Milestones:
Primary Market:
Secondary Market:
Stakeholders:
A safe, cost effective ultra-light aircraft that is suitable for
recreational flying by unlicensed pilots and emphasises ecologically
sustainable design principles as a method of market segregation.
1. Defining Scope by 2nd April
2. Draft Customer Needs Gathered by 2nd April
3. Breakdown and Allocation of Subsystems by 2nd April
4. Establishing Importance of Needs within Sub-system by 9th
April
5. Further Decomposition of Subsystem by 9th April
6. Identified Importance of Needs by 9th April
7. Concept Generation by 30th April
8. Subsystem Budget Allocation by 30th April
9. Concept Screening and Recommendation by 7th May
10. Concept Selection and Life Cycle Analysis by 21st May
1. Middle Income earners
2. Active sports minded people
1. Thrill Seekers
2. Flying Enthusiasts
1. Users
2. Retailers
3. Manufacturers
4. Sponsors
5. Members in Design Team
Table 1: Mission Statement: Ecologically Sustainable Ultra-light Aircraft
Summary of System needs
With the input from all the subsystems, the following is the compiled list of the needs for
the project. Using these general needs of the system, each sub-system will study these
needs to determine how the needs of the project can be met by each sub-system.
Page 1
SYSTEM NEEDS
DESCRIPTION
Structurally sound
The plane is able to handle the weight of all the
equipment.
Safe
Safety of the pilot is studied to ensure that in the
event of any emergencies, safety is not
compromised.
Convenient to launch
Is able takeoff on a short runway.
Low Cost (running, capital service)
Cost of the entire system has to be within the
budget.
Offers independence in time, distance and Can travel a predetermined distance and
conditions for operation
duration.
Pilot can navigate
With the help of technology, the pilot will be
able to determine his/her location in relation to
the destination.
Convenient to store and transport
It is lightweight and can be easily transported
between locations.
Fun to use
The pilot will enjoy the experience of flying.
Communication
Communication between pilot and ground
controls crew is provided to receive/transmit
important information.
Easy to maintain
The system will not require extended durations
to check for faults.
Aesthetic / style / fashion
The outlook of the plane is pleasing to the eye.
Easy to operate
Controlling the aircraft should be as simple as
possible to cater to amateurs.
Good info feedback
Proper instrumentation is provided to inform
user of system information.
Reliable
System will not malfunction.
Comfortable
Vibrations and noise levels are minimized to
ensure pilot enjoys the experience.
Table 2: Summary of System needs
Description of Energy Conversion Sub-system
The energy conversion subsystem creates the propulsion necessary and with the lift
created by the wings and structure of the aircraft enables the plane to take-off from the
ground.
The focus of this sub-system will be to generate concepts to provide the required amount
of thrust, concepts generated include:
•
•
•
Internal Combustion Engine
Electric Motors
Jet Engines
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Page 2
As well as means to store energy:
•
Petrol
•
Batteries
The advantages and disadvantages of the generated concepts will be analysed and
through a series of selection criteria such as the needs-matrices matrix, concepts which do
not meet cost and weight limitations of the project will be eliminated.
2. Customer Needs
In this section the complete list of customer needs for the Energy Conversion Sub-system
will be presented. Also, will be indicated how those needs will be measure (Needs-Metrics
Matrix).
2.1 Customer needs hierarchy and importance
In the introduction chapter, a list of the customer needs for the overall system was
presented. Based on this list and on a complete analysis of interactions with other
subsystems, a detailed list of customer needs for the Energy Conversion Sub-system was
generated. The subsystem interaction needs are quite important for our subsystem (in
general, for every sub-system) because, our subsystem is a part of the whole system, and
there are relationships and impacts between the system’s components (sub-system).
At the beginning of the process, the data from customers had to be converted in terms of
customer needs, i.e. assuring that the needs are expressed in terms of “what” the system
does, being specific, describe the need as an attribute of the product, establishing positive
sentences and avoiding “must” and “should” [1]. To establish the relative importance of
the needs we relied on the consensus and experience of the team members and not on
feedback from real customers. The reason was basically the time and cost constraint. The
following are the needs organized in a hierarchy with the relative importance:
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Page 3
#
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Subsystem Customer Needs: Energy Conversion
Imp
The Energy Conversion system is efficient
The Energy Conversion maximize the power/weight ratio
2
The Energy Conversion provides a powerful thrust generation
3
The Energy Conversion system has a simple and robust design
The Energy Conversion system has a long life time
2
The Energy Conversion system is easy to maintain
3
The Energy Conversion System is easy to start
3
The Energy Conversion system provides measurements interfaces for important measurements
The Energy Conversion system provides performance measures
2
The Energy Conversion system provides safety measures
2
The Energy Conversion system is compatible with other subsystems
The Energy Conversion minimize the noise (does not interrupt comunication, does not diminish the pilot confort) 3
The energy Conversion minimize electromagnetic fields
3
The Energy Conversion has low friction
3
The Energy Conversion minimize vibration
3
The Energy Conversion keep the balance of the Aircraft
2
The Energy Conversion system is suitable to structure of the aircraft
3
The Energy Conversion system enable to control the thrust (stop, acceleration)
2
The Energy Conversion system is safe
The Energy Conversion system is protected against fire and water (enclosure)
2
The Energy Conversion does not catch fire or explode
2
The Energy Conversion system has a safe energy storage
2
The Energy Conversion system has a back up energy unit for security reasons (redundancy)
4
The Energy Conversion system is robust to a wide variety of environmental conditions
3
The Energy Conversion system is ecological sustainable
The Energy Conversion system minimize the level of smell experienced by the pilot
4
The Energy Conversion system minimize the level of pollution to the environment
2
The Energy Conversion system is economical
The Energy Conversion System is economical to buy
2
The Energy Conversion System is economical to run
2
Ranking
4
17
9
13
13
11
11
16
17
19
19
9
15
1
7
1
3
22
21
22
7
4
4
Table 3: Detailed Customer Needs for Energy Conversion System
1.
2.
3.
4.
5.
6.
7.
Extremely Important
Very Important
Important
Ambiguous
Not Very Relevant
Not Important
Not Required at all
The importance measure is based on scales of
Figure 1.
The needs for the sub-system serve as a unified
understanding of customer needs among members
of the group and will be the base for product
specifications and selection criteria in the following
steps of the product design process.
Figure 1: Scale to measure Importance
2.2 Metrics
To measure the degree to which our concepts, and our product, satisfy the customer
needs, a precise and measurable set of metrics was generated.
Table 4 contains the metrics along with the customer needs associated with them and the
unit used to measure the needs:
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Page 4
Metric No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Need Nos.
2
1,2,13
3,4,17
4
4
4
4
5
8
9
9
10,13,15,16
10,13,15,16
12,13
3,15,19,21
3,13,15,16,17
3,16,17
3,11,13
18
20
15,16
9
9
2,14
10
2
22
6.7
13
1,13
23
Metrics
Efficiency
Power to weight
Mean Time Between Failure
Number of part suppliers
Cost of parts
Specialised tools required
Time to perform servicings
Time to start
Noise level within Pilot accomodation
Electric field strength
Magnetic field strength
Rate of Heat transferred
Heat generated
Change in location of Centre of Gravity
Aviation environmental testing
Temperature required to cause failure
Power draw required to cause failure
Aviation vibration testing
Length of time back up energy source remains operational
Amount of hazardous substance in pilot accomodation
Enclosure fire resistance
Voltage rating of the Reg/Rec
Current rating of the Reg/Rec
generated torque
Modal test
Pressure test
Cost of the whole subsystem
Numbers of sensors
Dimension of the engine
Weight
Cost per flight hour
Units
% (Percent)
HP/Kg (Horse Power per Kilogram)
Years
# (List)
AUD$ (cost)
# (List)
Hours
Seconds
dB
Volts per meter (V m-1)
Teslas (SI units)
Watts (W=J/s)
J (Joule)
Cm
Binary
°C (Celsius Degree)
HP (Horse Power)
Binary
Mins
PPM (Parts per Million)
Fire-Resistance rating
Volts
Ampers
N m (Newton Meters)
Binary
Binary
AUD$ (cost)
# (Numbers)
cm x cm x cm
Kgs
AUD$ (cost)
Table 4: List of Metrics
2.3 Needs-Metrics Matrix
After identifying the metrics, “Needs-Metrics Matrix Table” is developed which further
indicates the metrics and the customer needs that they address based on Table 4.
Table 5 is the Needs-Metrics Matrix developed for the energy conversion subsystem.
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Page 5
Table 5 Needs-Metrics Matrix
X
X
Change in location of Centre of Gravity
X
X
X
X
X
X
X
x
X
X
x
X
Aviation vibration testing
X
Power draw required to cause failure
X
Length of time back up energy source remains operational
X
Amount of hazardous substance in pilot accomodation
x
x
Enclosure fire resistance
x
Voltage rating of the Reg/Rec
x
Current rating of the Reg/Rec
x
x
generated torque
x
modal test
x
pressure test
x
Cost of the whole subsystem
x
x
Numbers of sensors
x
Dimension of the engine
x
x
Weight
x
Cost per flight hour
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
X
X
X
Temperature required to cause failure
X
X
Aviation environmental testing
8
x
x
x
X
Heat generated
x
Rate of Heat transferred
7
Time to start
X
X
Magnetic field strength
6
X
Noise level within Pilot accomodation
X
X
Electric field strength
5
X
Time to perform servicings
4
X
Specialised tools required
3
X
Cost of parts
2
X
X
X
X
Number of part suppliers
X
Mean Time Between Failure
1
X
Power to weight
X
Efficiency
Page 6
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Needs
1 Maximize the power/weight ratio
2 Provides a powerful thrust generation
3 Has a long life time
4 Is easy to maintain
5 Is easy to start
6 Provides performance measures
7 Provides safety measures
8 Minimize the noise (comunication, pilot confort)
9 Minimize electromagnetic fields
10 Has low friction
11 Minimize vibration
12 Keep the balance of the Aircraft
13 Is suitable to structure of the aircraft
14 Enable to control the thrust (stop, acceleration)
15 Is protected against fire and water (enclosure)
16 The Energy Conversion does not catch fire or explode
17 Has a safe energy storage
18 Has a back up energy unit for security reasons (redundancy)
19 Is robust to a wide variety of environmental conditions
20 Minimize the level of smell experienced by the pilot
21 Minimize the level of pollution to the environment
22 Is economical to buy
23 Is economical to run
Metrics
2.4 Customer Needs Justification
To validate the completeness of our customer needs, we have to confirm that these needs
satisfy, at least, the general requirements of our mission. In our case, we could
affirmatively say that our sub-systems needs, cover the main attributes declared in our
mission: safety (needs number 15, 16, 17 and 18), cost effectiveness (needs number 22
and 23, an also needs 3 and 4), suitability for recreational flying (needs number 10, 11, 14
and 19) and ecological sustainability emphasis (needs number 20 and 21).
The emphasis is on the “ecological sustainability” need, the need that addresses the
Energy Conversion System minimization of the level of pollution to the environment. This
need has an importance value of 2, and is within the seven more important needs of our
sub-system.
As will be established later, the cost of our sub-system is about 30% of the total cost of the
system. Considering also that our target market is middle class families, it is very
important to be aware of the needs concerning cost. In our sub-system, the needs that
address cost have an importance value of 2, which reflects the high influence of this
variable in the final decision.
Regarding the less important needs, we can say that it is perfectly aligned with our target
market and project purpose. Even though it is good to have a sub-system that has, for
example, low friction, low vibration and easy to start engine, those needs are not the
characteristics that contribute more to the mission’s attributes stated above. So, it is
reasonable that these needs be of less importance, i.e. have less discriminative power
than the other variables, when decision about a particular concept has to be made.
3. Benchmarking and Specification
3.1 Benchmark
A good benchmark measures the customer needs according to the metrics established for
the subsystem. Of course, in our case, we could not buy and test all the criteria of the
energy conversion subsystem. The ways we carried out our benchmark, were based on
popular comparison criteria on available data such as
cost, fuel consumption and power/weight ratio.
We will give a brief explanation of each type of engine
used in our benchmark and in the end present a
summary table comparing the major metrics available.
Figure 2: Rotax 503
Rotax 503 and 447. 2 cylinder, 2 stroke fan cooled
engine with piston ported inlet, with electronic singleignition (503 dual ignition), exhaust system, carburetor,
rewind starter [2].
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Page 7
Figure 3: Rotax 912
Rotax 912. The Rotax 912 has 4 cylinder, 4 stroke
liquid/air cooled engine with opposed cylinders, dry
sump forced lubrication with separate oil tank,
automatic adjustment by hydraulic valve tappet, 2
carburetors mechanical fuel pump, electronic dual
ignition, electric starter, propeller speed reduction unit,
engine mount assembly, air intake system, and exhaust
system [3].
Rotax engines are the most popular engines in the
ultralight aircraft market. Some ultralight aircrafts using Rotax engines are: Tanarg 912 [4],
Piper J-3 [5], Clipper 912 [4], the BushCaddy R80 Model [6] and the Esqual Vm-1 [7],
between one of the most popular.
TRS 18 Turbojet. The Microturbo TRS 18-1 is certified
and it’s been in use for over 20 years in the airshow
Microjets. It uses a particular type of fuel, the Jet Fuel:
Jet A, JP-4 or JP5. At max power has a consumption of
47.2 gal./hr., which makes it very expensive to run [8].
EM-10. Aluminum 4 cylinder, in-line diesel engine, 2
valves/cylinder, DOHC, common rail injection system,
turbo charged, water cooled [9].
Electraflyer. Electric engine capable of providing 155
pounds(690 N) of thrust. It uses a lithium-polymer
battery that could be charged in 2 hours [10].
Figure 4: EM-10
Table 6 is a compiled list of data collected for the engines and motors which are used in
some existing ultralights:
Type
Internal
Combustion
Engine
Internal
Combustion
Engine
Internal
Combustion
Engine
Model
Rotax 447
Output Power Energy Source
29.5 kw (40
HP)
Regular
gasoline,
octane not
below 90
unleaded
Weight
Fuel
Consumption
31.4kg
20.9Litres/hr
31.4kg
24.1Litres/hr
55Kg
23.8Litres/hr
Assumed Fuel
Price
Price
Life span of
equipment
$5,877
4000 h
$7,046
4000h
$14,499
4000h
Rotax 503
34.30kw
(46HP)
Rotax 912UL
59.6Km
(81HP)
TRS-18
TURBOJET
890N -1780 N
Jet Fuel (Jet A,
JP4-JP5)
38.5 kg
178.4 Litres/hr
$0.889/Litre
$50,000
Diesel
EM-80
52.20kW
(70HP)
Diesel
96kg
10.3 litres/hr
$1.70/Litre
$19,062
5000 h
Electric Motor
electraflyer
13.43kW(18H
P)
Electricity
40 kg
13.43kw/hr/90%
motor efficiency
$0.1/kwh
$7,157
1500 h
Jet Engine*
$1.44 / Litre
-
Table 6: General Benchmark for Different Types of Engines
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Page 8
Based on the data in Table 6 and group’s intuition and research on the existing products
we came up with Table 7, benchmarking 5 types of energy conversion systems against 8 of
the most important customer needs:
Petrol
Engine
Diesel
Engine
Electric
Motor
Hybrid
Jet
Engine
Safe to operate
•••
•••
••••
••
•
Lightweight
•••
••
••••
••
•
Comfortable
•••
••
••••
•
•
Easy to operate
••
••
•••
•
•
Easy to maintain
••
••
••••
••
•
Low in cost
•••
••
••••
••
•
Reliable
••••
••••
•••••
••
••
Fun
••
•
••
•
••••
Eco sustainable
••
•
••••
•••
•
Table 7 Benchmarking table for 5 type energy conversion systems
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Page 9
3.2 Target Specifications
In terms of target specifications, 3 constraints were defined in our project for the Energy
Conversion System:
Since there are several, totally different, existing energy conversion systems with a wide
range of power, power/weight ration, price, etc. it is not possible to define rigid target
specifications for the specified metrics in an early stage. Choosing a specific kind of energy
conversion system will enforce restrictions for the various metrics. For instance, if we
choose a battery powered energy conversion subsystem we are bound with building the
aircraft with a lighter weight compared with an internal combustion engine.
During the course, the whole class reached a consensus over the following specifications:



Budget. Lower boundary of $8,194 and a upper boundary of $14,750(35% of the
whole budget)
Weight. Between 80Kg and 150Kg. The whole aircraft weight has to be within
200Kg and 500Kg.
Power. After a discussion with the aerodynamic group we were advised of the
need of at least 5 kW motor for generating the drag to lift a 200 kg aircraft.
4. Functional Decomposition
Functional decomposition refers broadly to the process of resolving a functional
relationship into its constituent parts in such a way that the original function can be
reconstructed (i.e., recomposed) from those parts by function composition. In general,
this process of decomposition is undertaken either for the purpose of gaining insight into
the identity of the constituent components (which may reflect individual physical
processes of interest, for example), or for the purpose of obtaining a compressed
representation of the global function, a task which is feasible only when the constituent
processes possess a certain level of modularity (i.e., independence or non-interaction) [1].
To explain it in the context of this project, functional decomposition firstly helps to clarify
the problem. In this specific case, it gives a functional picture of the sub-system and helps
us understand the energy conversion system in more depth, both externally and
internally.
Externally such as how the sub-system interacts with other sub-systems, what functions or
services the sub-system provides to others and the whole aircraft, and what are the
dependencies of the sub-system; and Internally such as the component relationships
between each other within the sub-system, what functions or services each component
provides to other components within the sub-system, and the dependencies of each
component on others.
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Additionally, it lays the strong foundations for the future work of concept research,
concept generation, concept screening, and concept selection during the design process.
The future work about concepts thus has something to base on.
Moreover, functional decomposition could also serve to map functions to physical
components, thereby ensuring that each function has an acknowledged physical owner, to
map functions to system requirements, and to ensure that all necessary functions are
listed and that no unnecessary functions are requested. Table 8, 9 and 10 show these sets
of dependencies.
4.1 Functions of our sub-system energy conversion
First we look at the functions from the system point of view, i.e. what services or functions
other sub-systems and the whole aircraft expect from our subsystem, and what we want
from them.
Necessary functions to provide:
Function description
To generate thrust or
propulsion to lift the aircraft
To which sub-system
Aerodynamic
structure sub-system
To provide interface to control
the energy conversion subsystem
To provide interface to
measure parameters needed
during flight
Control sub-system
Communication and
instrumentation subsystem
Explanation
The basic physics concept, to
overcome the gravity and drag
force.
The pilot needs to control the
direction and/or quantity of
the thrust or propulsion.
The pilot needs to know critical
flight parameters, e.g., engine
running speed
Table 8: Necessary functions to provide for energy conversion sub-system
Optional functions to provide:
Function description
To which sub-system
To provide electricity power
Aerodynamic
for movement of aerodynamic structure sub-system
structure
To provide electricity power
Control sub-system
for control instruments
To provide electricity power
Communication and
for communication and
instrumentation subinstrumentation instruments
system
To provide electricity power
Pilot accommodation
for pilot accommodation
and protection subinstruments
system
Explanation
The movement of flaps on the
wings could be driven and
powered by electricity.
The control sub-system may
need electricity power.
The instruments may need
electricity to power the
instruments.
Pilot seat could be electrically
adjusted; air conditioning may
installed.
Table 9: Optional functions to provide for energy conversion sub-system
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Necessary functions required from other sub-systems:
Function description
Provided some room or space
to place the physical energy
conversion sub-system
components
To which sub-system
Aerodynamic
structure sub-system
Explanation
We need to mount the engine
on the aircraft
Table 10: Necessary functions required from other sub-systems
Optional functions needed from other sub-systems: None
4.2 Function analysis on sub-system level
First, we started with a black box model illustrated in Figure 5 and then came up with the
functional decomposition of our subsystem (Figure 6).
Energy
Material
Energy
Conversion
sub-system
Signal
Energy
Material
Signal
Figure 5: Black box of a sub-system
Energy
Material
Signal
Input
Stored or converted energy on board
Energy source material, e.g. chemical
fuel, etc
None, e.g. wind power, solar power,
etc
N/A
Pilot controlling signal
Output
Kinetic energy
Decomposed material from energy
source material
N/A
Instrumentation signal
N/A
Table 11: Energy, material and signal flow of energy conversion sub-system
Function description on sub-system level
Energy:
energy from sources, either stored on board prior to flight, e.g., in the form
of fossil fuel or electricity, or converted on board, e.g., solar power or wind
power goes into the energy-conversion sub-system and then is converted
to kinetic energy to power the aircraft.
Material:
in some cases, the material input goes into our sub-system, and then is
consumed and decomposed after energy stored in it is released and
converted.
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Signal:
signal to control engine initiated by the pilot, via controlling sub-system,
transmits to our sub-system, and our sub-system reacts consequently. At
last, the control signal terminates and disappears. Another type of signal
for measuring some important parameters, e.g., fuel left in the tank, engine
running speed, etc, is generated within our sub-system, then output to
instrumentation sub-system.
4.3 Graphical representation of functional decomposition
External Energy
Conversion to
stored energy
Control
signal
Conversion
propulsion
to
Fuel waste
Energy storage
Conversion to
internal energy
Energy:
Signal:
Instrumentation signal
Material:
Figure 6: Functional Decomposition of Energy Conversion Sub-system
There are 4 components of energy-conversion sub-system:
a)
b)
c)
d)
Conversion to stored energy
Conversion to propulsion
Energy storage
Conversion to internal energy
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We realized energy conversion sub-system with different energy sources, can be
illustrated in different ways, but Figure 6 was the best one we came up with that could
cover different concepts, including jet engines, conventional internal combustion engines
or diesel engines, rocket engines, solar powered engines, man powered engines or electric
motors. At the time we created Figure 6, we took a great many of concepts in existence
into consideration.
4.4 Variations on functional decomposition
For some concepts and implementations of an aircraft, some parts of Figure 6 may not
exist. The following paragraphs explain some variations of Figure 6.

Solar-powered aircraft
Generally, energy conversion sub-system in this type of aircraft contains all 4 components
of Figure 6: Conversion to stored energy, Conversion to propulsion, Energy storage and
Conversion to internal energy.
During flight, solar energy is converted by solar panel to electricity energy and stored into
battery. Then the energy in the battery is converted to propulsion by electric motor and
propeller. Part of the electric energy is outputted to operate instruments on board.

Internal combustion engine aircraft
Basically, energy conversion sub-system in this type of aircraft contains 3 components of
Figure 6: Conversion to propulsion, Energy storage and Conversion to internal energy.
Energy stored in the fuel tank is converted to propulsion by engine and propeller. Part of
energy stored in the fuel tank is converted to electrical energy and outputted for
instruments on board.

Man-powered aircraft
There is only one component in Figure 6 for the energy conversion sub-system in this type
of airplane, i.e., Conversion to propulsion.
In this kind of aircraft, the pilot pedals to run the propeller, similar to the way of pedaling
a bicycle; meanwhile the propeller provides propulsion.

Aircraft without instruments requiring internal energy
This kind of aircraft could use any kind of energy source mentioned above, and the major
difference is that this kind of aircraft does not need the component of Conversion to
internal energy to supply electricity for the instruments on board. This could be due to
either instruments on board not needing electricity to run or instruments having their own
power supply, e.g., portable battery included in the instruments.
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5. Concept Generation
5.1 Concept tree generation
As mentioned in the last chapter we have 4 sub-subsystems to explore different concepts
relating to each of the sub-sub-systems. After discussing many different options, the
group decided that the easiest way to start would be to draw up concept trees and see if
any branches could be pruned at this early stage for every sub-subsystem.
5.1.1 Concept tree for the Conversion to Propulsion sub-subsystem
Jet
Gasoline
Conversion to
Propulsion
Internal
Combustion
Engine
Hybrid
Pedals
Diesel
Electric
Motor
Gas
Traditional
Propeller
Ducted Fan
Steam
Engine
Rockets
Figure 7: Concept Tree for Propulsion System
The group decided that steam engines may be able to be eliminated at this point in time.
A small amount of research was conducted and the group discovered steam engines came
in several different styles:



Steam Turbine
Steam Piston
Steam Rocket
The steam turbine and steam piston engines are generally used for power generation on a
large scale. They require water to be heated then fed into the engine to turn the rotors of
an electric engine. This could be adapted to turn the propeller of an aircraft; however, the
weight penalty is very large. It was decided that these concepts were unfeasible.
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The steam rocket is an interesting concept that requires further investigation. This has
been combined with the more general Rocket Motor class of propulsion generation.
5.1.2 Concept tree for Storage Energy sub-subsystem
Chemical
Liquid fuels
Gaseous fuels
Solid Fuels
Electrical
Battery
Capacitor
Store Energy
Nuclear
Mechanical
Heat
Hydraulic
Pneumatic
Spring
Tension
Flywheel
Thermo Electric
Phase change
(Steam)
Figure 8: Concept Tree for Storage System
The group considered all of these storage options and applied some pragmatic thinking to
decide which concepts were unfeasible. Research showed that batteries have higher
power density storage than capacitors and are much cheaper per kWh to use than
capacitors. Capacitors cannot store large amounts of energy like a battery can. For this
reason, the capacitor was eliminated as a power source in favor of a battery.
Energy stored in a mechanical fashion, as described in Figure 8, is good for actuating
objects for small lengths of time. These types of stored energy have the ability to deliver
high power; however, that power cannot be sustained and the stored energy is quickly
depleted. Clearly, the aircraft needs to sustain power over a large length of time;
therefore, the mechanically stored energy sources were eliminated from consideration.
Thermo-electric energy converts heat directly into electricity. The group could not think of
a feasible way to implement this effect in order to drive a propeller or turbine. It was
eliminated from consideration on this basis.
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5.1.3 Concept Tree for the Energy Conversion to Stored Energy subsubsystem
Solar
Photovoltai
cHeat
Pneumatic
generator
Hydraulic
Air Flow
generator
Electrical
Generator
Gather Energy
Regenerative
Braking
Human Power
Storage
Pneumatic
generator
Hydraulic
generator
Electrical
Generator
Pneumatic
generator
Hydraulic
generator
Electrical
Generator
Figure 9: Concept Tree for Energy Conversion to Stored Energy System
As mentioned in the Functional Decomposition chapter, these alternatives depend on the
actual solution and some are optional to any solution.
Conversion to
Internal Energy
(Battery)
Alternator +
Battery
Figure 10: Concept Tree for the Conversion to Internal Energy sub-subsystem
5.1.4 Concept Tree for the Conversion to Internal Energy sub-subsystem
The (battery) option refers just to the use of the same battery of the Stored Energy subsubsystem, for example, the case of the Electric Motor solution.
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The Alternator plus the Battery refers as an independent solution to provide internal
energy, for example, the case of an Internal Combustion Engine.
5.2 Putting It Together: Concepts
After discussing the pros and cons of the concept trees, the group decided that, in order
to move forward, the next step would be to generate some concepts. There are many
combinations that can be made from the concept trees above, so the most promising
concepts were put forward and analysed further. Listed here are the concepts that the
group decided held the most merit, along with several concepts that, at first glance may
be considered unfeasible; however, must be put to the project as a whole in order to
dismiss.
•
•
•
•
•
•
•
•
•
•
•
•
Conventional internal combustion engine
Internal combustion engine (diesel)
Hybrid Drive (Prius Technology)
Jet engine
Solar Powered and Solar Powered with Battery Assistance
Fuel Cell Powered with Battery Assisted Takeoff
Electric with rocket assisted take off
Human powered aircraft
Wind powered aircraft
Nuclear powered
Regenerative braking (applies to all concepts above)
Gravity Powered Aircraft
Block diagrams and a short description of each concept were then developed by the
group.
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5.2.1 Conventional internal combustion engine
The conventional internal combustion engine is well known to most people. The block
diagram shows the most common setup of the internal combustion system, which
converts fuel to mechanical energy by burning it. The mechanical energy is then converted
to propulsive force by turning a propeller and electrical energy by turning the rotor of the
alternator. This is a well established technology.
5.2.2 Internal combustion engine(diesel)
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The diesel engine has been included as a separate concept as popularity with diesel is
increasing. The motor vehicle industry has shown that modern diesel engines can be made
to run very efficiently and may even be a more cost effective option than a gasoline
engine. They do generally come at the expense of higher weight and initial cost; therefore,
may prove to be uncompetitive on that front.
5.2.3 Solar powered and solar powered with battery assistance
At this point in the concept generation phase, the group considers the solar aircraft one of
the forerunners for selection, based on the perception of low environmental impact
during operation. Shown here is the “SunSeeker” aircraft, which is a sailplane designed to
fly on solar power.
Figure 11: SunSeeker, Aircraft based on Solar power
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5.2.4 Jet engine
Figure 12: TRS-18 Turbojet
Engine
The TRS-18 Turbojet Engine is shown here. The most common configuration is to install
two of this size engines onto a light aircraft to generate sufficient thrust for flight.
5.2.5 Fuel cell powered with battery assisted takeoff
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Fuel cells are an emerging technology that does not currently appear feasible for
production aircraft. Boeing has demonstrated the ability to design and build a fuel cell
powered aircraft; however, their concept aircraft still requires battery assist for take-off.
5.2.6 Hybrid drive
A hybrid vehicle is a vehicle that uses two or more distinct power sources to propel the
vehicle. The most commonly used hybrid energy conversion system is hybrid-electric,
which is constructed of an internal combustion engine with an electric engine assist. These
types of hybrid energy conversion systems are highly favored because the fuel source is
already readily available. No costly efforts are required in order to establish readily
available fuels.
The hybrid-electric energy conversion system is able to take advantage of the pros of both
the internal combustion and electric motor power curves, while reducing the cons. As
shown in Figures 13 and 14, an electric motor has high torque at low rotational speeds
and low torque at high rotational speeds. Conversely, the internal combustion engine has
low torque at low rotational speeds and high torque at high rotational speeds. The hybridelectric drive system aims to combine these two curves in a mutually beneficial way.
The main disadvantage of performing this combination of two different drive systems is
quite a noticeable penalty in weight.
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Figure 13: Typical torque and horsepower curve for an internal combustion engine [11]
Figure 14: Typical torque and horsepower curves of an electric motor [11]
On the other hand we have “Hybrid fuel” engines that can use different fuel types. These
can be broken into two categories:
1. Flexible Fuel engines are able to use two or more fuels mixed together in the same
fuel tank. For example, an engine may be able to run on petroleum, ethanol or any
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mixture of the two. The advantage is that the user may select whichever fuel suits
at the time of purchase.
2. Dual Mode engines are similar to Flexible Fuel engines in that they can run on two
or more different fuels. However, unlike the Flexible Fuel engines, the two
different fuels cannot be mixed. These engines have the advantage that the user
may select the fuel that is most appropriate at the time of purchase; however, it
requires the use of multiple fuel tanks, which adds weight and volume.
5.2.7 Electric with rocket assisted take off
This is most applicable to aircraft wishing to perform tranist flights only. An aircraft utilises
more power taking off than in any other phase of flight. A much smaller electric motor
would be required if the propeller drive system only needed to sustain altitude. The rocket
assist would allow a once a flight boost to the take off and climb phase of the flight.
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5.2.8 Human powered aircraft
This technology has been demonstrated by the Gossamer series of aircraft. Shown below
is the Gossamer Albatross, which was the first pedal powered aircraft to cross the English
Channel. Although it is kind of neat, it probably would not be considered a recreational
aircraft.
Figure 15: Gossamer Albatross
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5.2.9 Wind powered aircraft
This concept is not meant to be used as a primary power source. Many aircraft use this
concept as an emergency backup power source for the onboard instrumentation. The
wind generators are shown in the two pictures below.
Figure 16: Wind Power Generator
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5.2.10 Nuclear powered aircraft
Figure 17: Nuclear Powered Aircraft Design Examples
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5.2.11 Regenerative braking
Regenerative braking is a concept whereby kinetic energy is transformed into some other
useful form of energy. An aircraft generally will generally only brake while on the ground
after landing, therefore, the most appropriate form of regenerative braking would be
attached to the wheels of the aircraft, in the style of a Prius type system. Electric
generators attached to the axles of the wheels would convert the kinetic energy into
electrical energy through the electromotive force of the generator.
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5.2.12 Gravity powered aircraft
The idea of a gravity powered aircraft was generated from Robert D. Hunt, a theoretical
physicist and inventor. It operates on principles of buoyancy, aerodynamic lift, and gravity.
Basically it consists of large zeppelin-like gas bags which are filled with helium from
storage tanks that are place on-board the aircraft. This generates the required buoyancy
for the aircraft to become lighter than air. Compressed air jets on the sides of the aircraft
add further propulsion to generate thrust. After aircraft ascends to the altitude limit
where it is no longer lighter than the air, some of the stored compressed air is expanded
into the dirigible areas, decreasing the buoyancy effect of the helium and starting the
aircraft's descent phase. During descent, wind turbines mounted on top of the aircraft,
drive air pumps which can refill the on-board compressed air storage [12].
Figure 18: The Gravity-Powered Aircraft [12][13]
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6. Concept Screening and Scoring
After coming up with several concepts the next stage would be concept screening.
Concept screening is frequently an iterative process and may not produce a dominant
concept immediately [1]. There are several methods for concept screening [1]:







External decision
Product champion
Intuition
Multi voting
Pros and cons
Prototype and test
Decision metrics
We divided this phase into three stages:
Preliminary Concept screening: a quick, approximate evaluation aimed at producing a few
viable alternatives
Concept Scoring: a more detailed, quantitative evaluation of the concepts
Further concept screening: a more careful analysis and finer quantitative evaluation of
the remaining concepts carried out after concept scoring
Throughout the screening and scoring process, several iterations may be performed, with
new alternatives arising from the combination of the features of several concepts.
6.1 Preliminary Concept Screening
In the preliminary concept screening we tried to narrow down the concepts based on pros
and cons, multi voting, intuition. Table 12 shows the concept screening table carried out
in this step. Some of the concepts do not conform to our mission statement or fall far out
of the customer needs criteria, and can be eliminated in a preliminary screening without
the need for a concept scoring process. Each group member was assigned to do a
comprehensive research on one or two concepts and present the pros and cons regarding
that concept. After a brainstorming session we eliminated a number of the concepts.
Since each person was researching one or two concept, which was basically different from
the rest of the group, there were chances that personal bias would affect the results. After
recognizing this flaw we decided to do a thorough research by all the group members, on
the concepts which were recognized to need further analysis. One of the common
mistakes is to eliminate a concept without enough evidence, in an early stage. To bypass
this problem we decided to keep some of the doubtful concepts that might have been
eliminated otherwise.
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Table 12 Concept Screening Table
Conventional
Internal
Combustion
engine
Solar
Powered
and Solar
Powered
with
Battery
Assistance
Economical
to buy
0
Maximize
Power to
weight
Jet
engine
Internal
combustion
engine
(diesel)
Fuel Cell
Powered
with
Battery
Assisted
Takeoff
Hybrid Drive
(Prius
Technology)
Battery
Powered
Electric
Motor
Aircraft
Human
Powered
Aircraft
Wind
Powered
Aircraft
Nuclear
Powered
Aircraft
Regenerative
Braking
-
-
+
-
-
0
+
+
-
-
0
-
+
+
-
-
-
-
-
-
-
Economical
to run
0
+
-
0
+
+
+
+
+
-
+
Suitable to
structure of
the aircraft
0
-
-
0
+
-
+
+
-
-
-
Minimizes
the noise
0
+
-
-
+
0
+
+
+
-
-
Energy
source
Efficiency
0
+
-
+
+
+
+
-
-
-
-
Ecological
sustainability
0
+
-
-
+
+
+
+
+
-
+
Selection
Criteria
Net Score
0
0
-4
1
3
0
4
3
1
-5
-3
Rank
4
4
6
3
2
4
1
2
3
7
5
Continue
Y
Y
Y
Y
Y
Y
Y
N
N
N
N
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In the following section we present the concepts which were eliminated thorough
preliminary concepts screening phase. As mentioned earlier, the elimination was basically
based on pros and cons, multi voting, intuition and concept screening table.

Human Powered Aircraft
Since the customer needs was initially generated from the 5 groups (whole class), we had
a talk with all the groups about this concept and there was consensus not to include
human powered aircraft due to low power to weight ratio and not satisfying the “ease of
use” need(Recreational aircraft mission statement).

Wind Powered Aircraft
This concept could not pass our initial screening since it couldn’t provide enough power to
weight ratio to generate thrust even in its most ideal setting. The only possible use we
could find was as an emergency source of energy for powering the internal devices in the
aircraft in case the main internal power source faces a problem.

Nuclear Powered Aircraft
Basically, the cost and weight of a nuclear reactor aircraft would be a lot higher than our
specification constraints.

Regenerative Braking
Regenerative braking was suggested as a concept for regaining energy on landing the
aircraft. Given the amount of time spent on the ground compared to in the air, this
concept was rejected. The perceived benefits of regenerative braking were insignificant
compared to the amount of additional weight and engineering effort required.
•
Gravity Powered Aircraft
Gravity powered aircraft is still a concept and hasn’t proven to be practically viable.
Nevertheless, it requires huge zeppelin like gas bags and cannot satisfy ultralight aircraft
size constraints.
6.2 Concept Scoring
Before further concept screening, concept scoring was carried out based on a selection
criteria. In the “customer needs” section we ended up ranking the customer needs. For
concept screening we use a subset of those needs. We selected 7 of the needs that scored
the highest and were also measurable. Table 13 shows the result of the scoring process.
The ratings are based on the information and data which were presented in the
benchmarking and concept generation section and group member’s intuition of the
concepts.
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Total Score
Battery Powered aircraft
Hybrid Drive (Prius
Technology)
Fuel Cell Powered with
Battery Assisted Takeoff
Internal combustion engine
(diesel)
Jet engine
Solar Powered and Solar
Powered with Battery
Assistance
Conventional internal
combustion engine
Economical to
buy
Maximize
Power to
weight
Economical
to run
Suitable to
structure of the
aircraft
Minimizes the
noise
Energy source
Efficiency
Ecological
sustainability
Weight
Rating
Weighted
score
Rating
Weighted
score
Rating
Weighted
score
Rating
Weighted
score
Rating
Weighted
score
Rating
Weighted
score
Rating
Weighted
score
0.2
3
0.6
1
0.2
2
0.4
3
0.6
1
0.2
2
0.4
3
0.6
0.15
4
0.6
2
0.3
5
0.75
4
0.6
2
0.3
4
0.6
2
0.3
0.15
2
0.3
4
0.6
2
0.3
3
0.45
4
0.6
3
0.45
4
0.6
0.1
3
0.3
3
0.3
3
0.3
2
0.2
2
0.2
1
0.1
5
0.5
0.1
2
0.2
4
0.4
1
0.1
2
0.2
4
0.4
2
0.2
4
0.4
0.05
3
0.15
4
0.2
2
0.1
2
0.1
2
0.1
3
0.15
2
0.1
0.25
2
0.5
5
1.25
2
0.5
2
0.5
4
1
3
0.75
4
1
1
2.65
4
Rank
3.25
2.45
2.65
2.8
2.65
3.5
2
5
4
3
4
1
Table 13 Selection Criteria for Energy Conversion System Selection
6.3 Further concept screening
As mentioned earlier, concept screening is an iterative process. Based on the concept
scoring, Solar and Fuel cell concepts scored among the highest. However in this stage we
decided to eliminate these two concepts mainly because they could not satisfy our budget
constraints. Moreover, Jet engine concept scored the lowest and was eliminated at this
point of time.
6.3.1 Solar Powered and Fuel Cell power Elimination:
Table 14 shows some specifications for existing solar powered aircrafts. As you can see,
the cost NASA’s Helios with a 30 kW solar array output, was about 9.7 m AUD.
Price
Helios
Pathfinder
Sunseeker
9.7 m AUD
-
Solar array
output
Wing Span
30kW
75.28
8kW
-
35
17.5
Motor
power
21 kW
5.98
Weight
600 kg
270 kg
91kg
Allowed
Mass
330kg
-
Table 14 Existing Solar Powered Aircraft Specifications [14][15]
From Table 14 and [16] we came up with Table 15 which is a comparison for investment
of equipment to generate 1kW for 5 energy sources.
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Energy Source
Investment of
equipment to
generate 1kW
Lifespan of
equipment
before major
overhaul or
replacement
Solar
Fuel Cell
200 AUD/Watt
3000 AUD
20years
2000h
Lithium Polymer
battery
1500 AUD
1500h
Gasoline
Diesel
30-100 AUD
40-100 AUD
4000h
5000h
Table 15 Cost Comparison of 5 different energy sources to generate one kW of energy
Based on the Tables 14 and 15 it is obvious that the cost of the solar concept falls out of
our budget by a high margin. Producing 1 kW of solar power (using high efficiency solar
cells) will require (1000 * 209 = 209,000 AUD) investment in equipment.
On the other hand, fuel cells cost twice as much as batteries. Considering the fact that fuel
cells would require auxiliary equipment such as hydrogen tanks, which makes them to
weigh much more than batteries and fuel cells are usually used in a combination with
batteries, the finished price of fuel cell concept will be even more than twice of the
batteries. Therefore we calculated that the cost of fuel cell powered aircraft falls out of
our budget limit.
6.3.2 Jet Engine Elimination
As in the solar powered and fuel cells concepts, the main drawback of this option is the
cost. (This concept also ranked the lowest in concept scoring section)
As expressed in Table 6, the cost of buying and running this type of engine is extremely
high.


Buying cost: AUD$50,000
Running cost: AUD$32,000 (1 year, 4 hours a week, consumption of 178.4 Litres/hr
and a fuel price of $0.889/Litre)
Clearly, this is out of our budget and target market, for this reason this option is also
discarded.
7. Concept selection and Justification
After the analysis of the last chapter (concept screening), we are left with mainly two
options: Internal Combustion Engine (gasoline/diesel/hybrid) and Battery Powered
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
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Aircraft with Electric Motor. In this chapter we will analyse these concepts and make a
recommendation based on our findings.
We have done an analysis of cost vs. power and cost vs. power/weight ratio for existing
internal combustion engines and electric motors. Data sets in Table 16 and 17 show the
results of the analysis. Figure 19 and 20 are a graphical representation of the data sets for
a better understanding.
Model/Brand
Rotax 582
Rotax 503 single Carb
Rotax 503 dual Carb
Rotax 447
Rotal 912 UL
Rotal 912 ULS
Rotax 914 UL
Power
(HP)
65
46.5
50
39.6
81
100
115
Internal Combustion Engine
Cost
Weight
(AUD)
(Kg)
Fuel Weight(Kg)
7951
36
15
5916
37.4
17
6070
38.3
20
5105
32.6
22
16077
55.4
25
18389
56.6
30
26827
70
35
Power/Weight
1.275
0.855
0.858
0.725
1.007
1.155
1.095
Table 16: Cost vs. power Data Set for Internal Combustion Engine
Model/Brand
ElectraFlyer
PMG132 72v
PMG080 24v
LM202 60v
Power (HP)
18
10.108
2.24
57
Electric Engine
Cost
(AUD)
Weight
3785
11
2039
24.8
805
7.5
6000
20
Battery Weight
35
19.5
4.3
110
Power/Weight
0.391
0.228
0.190
0.438
Table 17: Cost vs. power Data Set Electric Motor
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30000
Cost(AUD)
25000
20000
Internal Combustion
Engine
15000
Electric Engine
10000
Linear (Internal
Combustion Engine)
Linear (Electric Engine)
5000
0
0
50
100
150
Power(kW)
Figure 19: Cost vs. Power comparison, Internal Combustion Engine and Electric motor
30000
25000
Internal Combustion Engine
Cost(AUD)
20000
15000
Electric Engine
10000
Linear (Internal Combustion
Engine)
5000
0
0.000
Linear (Electric Engine)
0.500
1.000
1.500
Power/Wieight(kW/kg)
Figure 20: Cost vs. Power/Weight comparison, Internal Combustion Engine and Electric motor
As you can see, it is very difficult to directly compare an internal combustion engine with
an electric motor based on the above charts since both cost and power/weight ratio for
the two concepts occupy different regions of the charts. A more appropriate method
would be to conduct a life cycle analysis on both, in order to capture the operating costs
of each. A brief life cycle analysis for a type of internal combustion engine and electric
motor is presented in the following section.
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7.1 Life Cycle Analysis – Internal Combustion Engine
Specifications
 59.6 kW @ 5800 RPM
 60 kg with electric starter,
carburetors, fuel pump, air
 filters and oil system
 19.2 litres/h
Figure 21: Rotax 912
Energy analysis




Assume it takes 100 MJ to produce 1 kg of raw material.
It consumes 60kg*100MJ/kg =6,000MJ to produce this engine.
Assume
it
can
run
1500hrs.
It
consumes
litres/h*34.6MJ/litre=996480MJ
In total 6,000MJ+996,480MJ=1,002,480MJ
1500hrs*19.2
Waste analysis
Table 18: Waste analysis for Internal Combustion Engine (Rotax 912)
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Price analysis
Rotax 912
8 spark plugs every 200 hours ($5 each)
Oil filter and oil every 100 hours
Petrol (28800× $1.5)
Total cost (1,500 hours of operation)
$12,500
$280
$275
$43,200
$57,005
7.2 Life Cycle Analysis – Electric Motor
Basically, electric motors don’t have any sort of emissions; therefore we haven’t
presented a waste analysis for this part.
Price analysis
Propulsion Parts Kit
o Build your own ultralight
$4,542
Battery Packages
o Large lithium-polymer pack 5.6kWh
$9,000
Battery Charger
o High power with lithium ion charge curve-auto
shutoff
$1,074
Battery Life Cycles – 1,000h
Battery Disposal Rate : 6.3% of the Battery Price
Electricity Bill
o ($0.2/kWh × 5.6kWh × 1000 )
Total cost (1,500 hours of operation)
$567
$1,120
$25,079
7.3 Concept Recommendation
In the previous section, the total cost of a generic internal combustion engine (Rotax 912)
and an electric motor (Electra Flyer) were presented. Although the capital cost of the two
systems were almost the same, for a lifecycle period of 1500 hours, internal combustion
engines costs more than twice as much as the electric motor. Furthermore there is no
significant waste associated with electric motors. Based on our analysis and also from the
concept scoring section (battery powered aircraft ranked the highest compared with
internal combustion engine type concepts which ranked number 4 overall) we
recommend the electric motor concept for the ultralight aircraft.
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The major advantages of an electric powered aircraft are listed below:






Improved maneuverability due to the greater torque from electric motors
Increased safety due to decreased chance of mechanical failure
Less risk of explosion or fire in the event of a collision
Less noise
Cheaper to run
Ecological sustainable
The main disadvantage of the electric motor is the decreased range (independence in time
and distance). In the following chapters we will present a high level design of the solution
and the reasons above this, and also we will suggest some methods and technologies that
can compensate for this drawback.
8. Concept developing and description
For developing our own concept, we did a comprehensive research on electric motors and
batteries and went through several existing battery powered aircrafts. Thereafter we tried
to choose, modify or design our own subsystem.
8.1 Battery
In this section we try to do an analysis based on the pros and cons for the potential
battery types. (Pictures taken from [17] )
Lithium-ion battery
Advantages:
1. Best energy-to-mass ratios
2. No memory effect
3. Slow loss of charge
Disadvantages:
1. Mistreatment may cause explosion
2. Relatively expansive
Figure 22 Lithium-ion battery
Lithium polymer battery
Advantages:
1. Lower manufacturing cost
2. More robust to physical damage
3. the weight of lithium polymer battery
can be lighter than lithium-ion battery
4. It can be specifically shaped to fit the
device it will power.
Figure 23 Lithium polymer battery
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Disadvantages:
1. Overcharging lithium polymer battery may cost it explosion.
2. Half slight memory effect
3. Still have some problems with internal resistance. The longer charge
times and slower maximum discharge rates compared to more
mature technologies.
Lead-acid battery
Advantages:
1.
2.
3.
4.
Disadvantages:
1.
2.
3.
Relatively large power-to-weight ratio,
Low cost
Successful recycling system
Supply high surge currents
Lowest energy-to-weight ratio
Low energy-to-volume ratio
Pollution
Figure 24 Lead-acid battery
Nickel-metal hydride battery
Advantages:
1. Relatively cheaper
Disadvantages:
1. Relatively higher self-discharge rate
2. Lower volumetric energy density
Nickel-Cadmium battery
Advantages:
1. Good charging efficiency
2. Good energy density
Disadvantages:
1. Relatively Higher Cost
2. Very considerable negative
temperature coefficient
Figure 25 Nickel-metal hydride battery
Figure 26 Nickel-Cadmium battery
Based on the pros and cons the group recommended the use of lithium polymer battery
for the ultralight aircraft.
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8.1 Electric Motor
Table 19 lists 4 types of existing battery powered aircrafts and their motor specifications:
Type of Aircraft
Type of motor
Weight(kg)
Rotational
speed(rad/min)
Output power
Power/weight(hp/kg)
Cost(AUD)
Antares 20Eno
[18]
Brushless DC
Motor
<30
Electra flyer
[10]
Brushless DC
Motor
11.8
AE-1 Silent
[19]
Brushed DC
Motor
8.5
APAME
Electra [20]
Brushed DC
Motor
11
1500 -1700
1500
3400
3279
42kW/57hp
>1.9
>10,000
14kW/18hp
1.52
4,000
13/kW17hp
2
NA
18kW/24hp
2.1
NA
Table 19 Motor specifications for some existing battery powered aircrafts
To choose a type of motor for our design we went through different types of motors and
tried to identify the best option for ultralight use. The following section describes our
findings.
8.1.1 DC motor [21]
DC motor is designed to run on DC electric power. The most common DC motor types are
the brushed and brushless types, which use internal and external commutation
respectively to create an oscillating AC current from the DC source.
8.1.1.1
Brushed DC motor
The classic DC motor design generates an oscillating current in a wound rotor with a split
ring commutator, and either a wound or permanent magnet stator. A rotor consists of a
coil wound around a rotor which is then powered by any type of battery.
Comments:
It is able to provide variable speeds. However, the brushes wear out and need
replacement which is undesirable and can be expensive for the consumer. The process of
brush wear also creates dust.
8.1.1.2
Brushless DC motor
A brushless DC motor is a synchronous electric motor which is powered by direct-current
electricity and which has an electronically controlled commutation system, instead of a
mechanical commutation system based on brushes. In such motors, current and torque,
voltage, and rpm are linearly related.
Comments:
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Brushless DC motors are in widespread use in high performance motion control products.
8.1.2 Torque motor
A torque motor is a specialized form of induction motor which is capable of operating
indefinitely at stall without damage. In this mode, the motor will apply a steady torque to
the load. A common application of a torque motor would be the supply- and take-up reel
motors in a tape drive. Driven from a higher voltage, the torque motors can also achieve
fast-forward and rewind operation without requiring any additional mechanics such as
gears or clutches.
Comments:
High power efficiency, more torque and more speed compared to classical torque motors.
It also has high motor robustness and very high continuous torque.
8.1.3 AC motor
AC motor is an electric motor that is driven by an alternating current. It consists of two
basic parts, an outside stationary stator having coils supplied with AC current to produce a
rotating magnetic field, and an inside rotor attached to the output shift that is given a
torque by the rotating field.
Comments:
AC motors are simple and cheap to make and can be reliable. However, AC motors which
used in familiar appliances operate at a fixes speed. To achieve variable speeds requires
the extra cost and complexity of control systems multiple windings or gearboxes.
8.1.4 Slip ring
The slip ring or wound rotor motor is an induction machine where the rotor comprises a
set of coils that are terminated in slip rings to which external impedances can be
connected. The stator is the same as is used with a standard squirrel cage motor.
The slip ring motor is used primarily to start a high inertia load or a load that requires a
very high starting torque across the full speed range.
8.2 Choosing the right motor
From the information in the previous section, we decided that since the output of a
battery is DC current it is best to choose a DC motor. If an AC motor is used in the
propulsion system, a converter is needed. In addition, the AC motors are more suitable for
applications were the speed is fixed and in the case of an aircraft, we need control
systems and multiple windings or gearboxes to adjust the rotation speed of an AC motor
which means more weight and cost. On the other hand, if we use a split ring motor,
increasing the load will cause the motor to slow down until the load and the motor torque
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
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are equal. The slip losses in this situation can be very significant and the speed regulation
is also very poor.
There are two types of the DC motors, one is brushed DC motor and the other is brushless
DC motor. Brushed DC motor is the classic design of the DC motor. However, at higher
speeds, brushes have increasing difficulty in maintaining the contact, therefore creating
sparks. This limits the maximum speed of the machine. The imperfect electric contact also
causes electrical noise and affects the operation of the internal instruments. The brushes
and the commutator itself will require maintenance and replacement.
A brushless dc motor is beneficial on the following grounds:
 High Performance
 High Reliability
 Low Maintenance Cost
 Smooth & Quite Operation
Because of the benefits that brushless dc motors have over brushed dc motors and based
on the fact that their cost difference is not significant, the group decided that a brushless
dc motor is the right choice for out ultralight aircraft.
8.3 Design a new motor
8.3.1 Brushless motor basics [22]
Figure 27 illustrates a hypothetical two-pole three-slot
brushless motor. The rotor has one permanent magnet (two
poles), and the stator has three electromagnets (three slots)
and three connection points. Notice there are three
connection points to receive power from the brushless ESC
(Electronic Speed Control). In the state represented by
Figure 27, power is being applied to the two leads labelled
"+" and "-", which energizes the electromagnets as shown.
The upper left electromagnet is attracting the rotor’s north Figure 27 Hypothetical two-pole
pole, the lower left one is repelling it, and the right hand three-slot brushless motor (34)
electromagnet is repelling the rotor's south pole. As the
rotor turns, the ESC will change the leads for which power is applied to. Sometimes only
two leads will and at other times all three leads will.
8.3.2 Final Design based on Antares 20E
Figure 28 shows the example of a newly designed electric brushless DC motor. EM42 is a
brushless 42 kW external rotor electric motor. New power electronics and a large slowly
rotating propeller were developed into one system and tailored especially for the Antares
20E into an optimized configuration. It is a brushless fixed-shaft electric motor running on
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DC-DC current. Running at 190 - 288V, and pulling up to 160A, the 42kW motor can deliver
maximum torque over a wide RPM range. With a total efficiency of 90% and a maximum
torque of 216 Nm, the motor has exceptional performance.
By using relatively few high quality components, risk of failure is minimized. The Antares
20E propulsion system causes very little vibration. This avoids vibration related problems,
thereby increasing total system reliability.
Furthermore, all electrical components are
attached to the non-moving part of the motor. The
motor itself contains only 4 parts (2 ball bearings
and 2 sealing rings) which are subject to wear. The
simple mechanics of the motor results in simple
and low cost maintenance with very long
maintenance intervals. Maintenance consists of
exchanging the two sealing rings, and it must be
performed every 200 hours of motor time or every
10 years, whichever happens first.
Figure 28 EM42 42kW Brushless DC Motor (18)
8.4 Propeller selection/design specifications
8.4.1 Pitch and types of propellers
The most fundamental characteristic of a propeller is the pitch. The way in which pitch is
controlled differentiates one family of propeller from another. When describing the affect
of pitch, a useful analogy is that of an automobile gearbox.
Propeller theory includes a variety of concepts that may at times be called pitch. Pitch can
refer to the blade angle with respect to a flat plane, the distance that a propeller will
advance through the air for each rotation. Essentially these concepts all describe the same
thing. To use our automobile analogy, pitch is like the gear ratio of the gearbox. The
important thing to note with pitch is that it is available in a wide variety of degrees, much
like different gear ratios. To demonstrate, consider the following examples:

A fine pitch propeller has a low blade angle, will try to move forward a small
distance through the air with each rotation. It requires relatively low power to
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
rotate, allowing high propeller speed to be developed, but achieving only limited
airspeed and generating high thrust. This is like having a low gear in the
automobile, which is good at accelerating.
A coarse pitch propeller has a high blade angle, will try to advance a long distance
through the air with each rotation. It requires greater power to rotate, limiting the
propeller speed that can be developed, but achieving high airspeeds and
generating low thrust. This is like having a high gear in the automobile, which is
good at maintaining the aircraft with high speed.
There are 3 major families of propellers, fixed pitch propeller, ground adjustable propeller
and variable pitch propeller.
8.4.1.1
Fixed Pitch Propeller
For a fixed pitch propeller, the pitch is fixed by the manufacturer. The performance of an
aircraft is determined from the time the propeller is fitted, and is going to be limited
within the constraints of the propeller. An analogy with an automobile is as though the car
had only one gear.
8.4.1.2
Ground Adjustable Propeller
Many propellers manufactured and sold for ultralight and experimental aircraft are
ground adjustable propellers. These propellers have the advantage of being able to have
their pitch adjusted before each flight if required, taking into account the type of flying
you intend to do. This can be compared to having a gearbox in the car that could only be
changed prior to the start of the journey.
8.4.1.3
Variable Pitch Propeller
Variable pitch propeller is a special type of propeller with blades that can change their
pitch. To use the automobile analogy again, the car now has a real gearbox that gear can
be changed on the fly like a real car. In addition, rather than being limited to 4 or 5 gears,
you can utilize any pitch along the continuum from maximum to minimum. The pitch of
the propeller may be controlled in flight to provide improved performance in each phase
of flight. By this way, the propeller may generate different thrust levels and air speeds
[23].
8.4.2 Propeller diameter
Propeller efficiency is the ration of the thrust power (thrust x aircraft velocity) output to
the engine power input.
For a given power, it is always desirable to use the largest possible propeller diameter,
which may be limited by mechanical restrictions or aerodynamic constraints. That’s why
most man or solar powered aircraft use large, slowly turning propellers, so that they can
move a large volume of air and accelerate it slowly to achieve the maximum efficiency.
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The most efficient system is to utilize the greatest propeller diameter possible.
8.4.3 Number of blades
Increasing the aspect ratio of the blades with adjustable pitch propeller reduces drag. But
the amount of thrust produced depends heavily on blade area. In order to increase blade
area, we could increase the propeller diameter. Since the diameter cannot be extended
unlimitedly, the other way around is to increase the number of blades. But there is a
limitation for number of blades, which is that using a large number of blades increases
interference effects between the blades. Thus, considerations and experimentations shall
be taken to decide the number of blades [24].
8.4.4 Material of blades
There are a great number of materials used for aircraft propeller, including but not limited
to metal, carbon fibre, glass fibre, wood and nylon.
The best materials for propellers are glass or carbons reinforced composite material but
are also the most expensive ones. The extra strength of these materials allows for a
better-performing propeller [25].
8.4.5 Selecting criteria
Based on discussion and introduction above, we decided that we prefer propellers with
following characteristics to maximize the performance.




Variable pitch capability
Adjustable long diameter
Multiple blades
Light and strong material
8.5 Final Specifications
In the previous two sections we came up with the following options for battery and
motor:
1. Lithium Polymer battery
2. Design a very efficient motor(90% efficiency) with the desired output
power
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Total
Weight of
the Energy
Conversion
System(kg)
Total
Price
(AUD)
Provided
Power
(Motor
Power)
(kW)
Power
to
Weight
Ratio
Energy(kWh)
Battery
Weight(kg)
Battery
Price(AUD)
Motor
Weight(kg)
Estimated
Motor
Price(AUD)
7
35
11000
5
2000
40
15000
8.8
0.22
14
70
20000
8
4000
78
20008
17.7
0.227
33
165
50000
15
10000
180
60000
43
0.239
Table 20 Energy conversion Specifications for 3 set points
Table 20 shows the overall energy conversion specifications calculated for three set
points. For any other desired set point we can refer to Figure 29, 30.
Figures 29, 30 show the amount of power we can provide and how it relates to cost and
weight of energy conversion subsystem. The aerodynamic group should make the final
decision on the option of power-weight-cost setting. For example, if the requirement is 25
kW for generating the drag for a total aircraft weight of 300 kg, the cost would be
something around 30000 AUD and we are aiming at a target weight of around 110 kg for
the energy conversion subsystem. It is important to note that for this setting, the allowed
cost for the rest of the subsystems should not exceed (300-110 = 190 kg).
Cost vs. Power
70000
Price(AUD)
60000
50000
40000
Cost
30000
20000
10000
0
0
10
20
30
40
50
Power(kW)
Figure 29 Cost vs. Power for final design
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Total Energy Conversion
Weight
Weight vs. Power
200
150
100
50
0
0
10
20
30
40
50
Power(kW)
Weight
Figure 30 Weight vs. Power for final design
Based on the selection criteria we introduced in section 8.4, we chose IVOPROP In-Flight
Adjustable Ultralight Model propeller. It has the following major characteristics:












18"-52" or 35"-70" pitch range
48"-72" diameter
In-flight adjustable pitch
Carbon/graphite fibre/composite
All blades protected by stainless steel leading edges
Light, strong, efficient, quiet, smooth
Unique pitch adjustment design no protractor or pitch blocks required for
adjustment
Beautiful high gloss black gel-kote finish
Easily and quickly converts from 3 blade into 2 blade configuration - giving you a
spare blade
Blades individually replaceable
3-Blade version weights 9.5 Lbs
3-Blade version costs $1050.00 AUD [26]
It has all the enhancements we need to increase a propeller’s performance. Therefore, we
decided to choose this one. However choosing this model adds a linkage between our
group and the control group
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9. Recommendations for next steps
Increasing the efficiency of a battery powered aircraft can be done in several ways. In this
chapter we will present some alternatives that should be considered when going into a
detailed design stage.
9.1 Increase motor efficiency
a) Loading
Since motors run most efficiently near their designed power rating, it is good
practice to operate between 75 percent and 100 percent of full load rating. If
we could design our motor so that it would work around its operating point
during the flight we can increase the efficiency of it.
b) Maintenance
Regular maintenance ensures a better efficiency for the motor during its life
cycle.
c) Designing a more efficient motor
We can achieve an efficiency increase from three to eight percent.




Heavier copper wire,
higher core-steel grade,
thinner core laminations,
better bearings and reduced windage design
d) Electronic Variable Speed Drives (VSDs)
Using a variable pulse width speed controller will increase the motor efficiency.
This will probably fit in the control group subsystem.
9.2 Integrating with Fuel Cell and Solar Cell
Because fuel cells basically produce electricity, they are a suitable replacement for
batteries. It is estimated that by 2015 the cost of the fuel cells would be competitive with
fossil fuels (30$/kW). Solar technology is also improving very fast and each year we are
observing solar cells with decreased prices and better performance. Third generation solar
cells will have an estimated efficiency of up to 45% compared with the second generation
that is the state of the art technology for aviation purposes which is something around
30% [27]. On the other hand fossil fuel prices are skyrocketing. Since we are using an
electric motor for generating thrust we can easily upgrade our system to a fuel cell/solar
cell powered aircraft. Moreover the battery technology has a fair increase every year.
These reasons further justify the selection of an electric motor for the aircraft.
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Figure 31: Cost Analysis of Fuel Cells
9.3 Improved aerodynamic structure
An aircraft with a better design for the aerodynamic structure will generate more lift with
the same amount of thrust generated by the propeller. Investing in the aerodynamic
design would have a positive effect on energy efficiency.
10.
Conclusions
During the process of product design and development that we followed through this
semester in this course we realized that designing a complex system is not an easy task.
Without a systematic approach we could easily get lost in the trying. Even though this is
not a real life situation and sometimes decisions were made with poor data and
experience, it was possible to see important aspect of the complexity of this process.
During the elicitation of customer needs we realize that besides the end customer (the
people that will finally use the product) and other stakeholders (those who also have
needs and constraint the decision) an important role play the “internal customers”, i.e.
those that are part of the design project of other sub-system that interact with our
subsystem. Because of the relationship and impacts that exist between sub-systems,
requirements of the other sub-systems towards our sub-system also has to be established
as customer needs in order to limit solutions to feasible ones, and finally have a robust
design as a whole.
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The benchmarking section was done individually and later presented to the group. This
brought the opportunity to gain a lot of insight and even the level of knowledge within the
group. Many members of the group were not expert of the subject matter, especially
about engines and thrust generation, so this benchmark gave the group the opportunity
to see how it works and distinguish its functions, which was very helpful in the Functional
Decomposition stage.
Decomposition of the Energy Conversion system in functions was a hard task and many
hours of discussion basically because of the little knowledge of the matter. Following the
systematic approach taught in the lectures, facilitated enormously the separation of
functions. We realized that the Functional Decomposition process was tremendously
helpful to diminish the complexity of the system, giving individuals less complex and more
manageable parts, but more importantly, the ability to think (and create if selected) novel
possible solutions when brainstorming alternatives.
As mentioned before, the Functional Decomposition helped us to think of many different
solutions, many feasible and others unfeasible when contrasting with the mission
statement. Even though we knew we will prune those alternatives, the Concept
Generation stage gave us the opportunity to be creative. An important lesson learned was
to be structurally creative, i.e. had the opportunity to think of “crazy” solutions and also
think “out of the box”, but considering the different functions and the purpose of the
complete sub-system (function goal).
During the Concept Screening and Scoring we realized that the decision of partial solutions
and final solution was made based on extremely poor information. Of course, in real life
situations, many decisions are taken based on poor data and lack of information.
Nonetheless, the more information researched the better the decision that can be made.
The lesson learned here is that we have to try to get as much information as possible
according to our constraint. In our case, in a one semester course project (constraint) we
felt the decision was made with the best information we had on hand.
For the Concept Justification highlights two main approaches that contributed to a better
decision: Life Cycle and Cost Analysis. Life Cycle Analysis was an important decision factor
because of the Ecological Sustainability purpose of the Design. This analysis help us to see
the “big picture” in terms of how much a proposed solution could contribute (or the
opposite) to the environment. At the other hand, Cost Analysis helped us decide in terms
of future costs, because of course there are solutions that are more profitable (or in our
case, less expensive) in present values.
In general, we can conclude that follow a systematic approach is extremely important
when dealing with complexity, and that information should be taken with the best
information available given the constraints.
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Page 51
References
1. Ulrich, Karl. Eppinger, Steven. Product Design and Development.
2. Rotax Aircraft Engines. Aircraft - Engine 503. [Online] [Cited: May 31, 2008.]
http://www.rotax-aircraft-engines.com/a_engine_503_447.htm.
3. Aircraft - Engine 912. [Online] [Cited: May 31, 2008.] http://www.rotax-aircraftengines.com/a_engine_912.htm.
4. Air Creation. Air Creation. [Online] [Cited: May 31, 2008.] www.aircreation.com.
5. Savage Cub. The Ultimate Australian Bush Plane. [Online] [Cited: may 31, 2008.]
http://www.mcp.com.au/cub/.
6. Canadian Light Aircraft Sales & Service Inc. BushCaddy. [Online] [Cited: May 31, 2008.]
http://www.auf.asn.au/buyguide/bushcaddy.html.
7. Ultra Aviation. Ultra Aviation - Esqual Vm-1. [Online] [Cited: May 31, 2008.]
http://www.ultraaviation.com.au/images/esqual_vm.htm.
8. BD-5. The BD-5 Web Site. [Online] [Cited: May 31, 2008.] http://www.bd5.com/.
9. Eco motors. Eco-Motors. [Online] [Cited: May 31, 2008.] http://www.eco-motors.com/.
10. Electric Aircraft Corporation. ElectraFlyer. [Online] [Cited: May 31, 2008.]
http://www.electraflyer.com/index.html.
11. Sacramento State University. Power-Torque Trade offs. [Online] [Cited: May 31,
2008.] http://www.csus.edu/indiv/o/oldenburgj/ENGR1A/PowerTorqueTradeoffs.doc.
12. Damn Interesting. The Gravity-Powered Aircraft. [Online] [Cited: Jun 01, 2008.]
http://www.damninteresting.com/.
13. YouTube.com. Gravity
2008.]http://www.youtube.com.
Powered
Aircraft.
[Online]
[Cited:
Jun
1,
14. Solar Flight. Solar Flight SunSeeker. [Online] [Cited: May 31, 2008.] http://www.solarflight.com.
15. Wikipedia. Wikipedia - Solar
http://en.wikipedia.org/wiki/Solar_cell.
Cell.
[Online]
[Cited:
May
31,
2008.]
16. Batteries in a Portable World. The Fuel Cell: is it ready? [Online] [Cited: May 31,
2008.] http://www.buchmann.ca/Article1-Page1.asp.
17.
Wikipedia.
Wikipedia
http://www.wikipedia.com.
Battery.
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
[Online]
[Cited:
May
20,
2008.]
Page 52
18. Lange Aviation GmbH. [Online] [Cited: May 2008, 31.] http://www.langeflugzeugbau.com/.
19. Air Energy Entwicklungsgesellschaft mbH & Co KG. . Willkommen bei Air Energy!
[Online] [Cited: May 20, 2008.] http://www.airenergy.de/.
20. Association pour la Promotion des Aéronefs à Motorisation Électrique. [Online]
[Cited: May 31, 2008.] http://www.apame.eu/.
21. Kollnorgen. Direct Drive DC Torque Motors.
22. Hanselman, Dr. Duane. Brushless Permanent Magnet Motor Design.
23. Recreational Aviation
http://www.auf.asn.au/.
Australia.
[Online]
[Cited:
Jun
01,
2008.]
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25.
Wikipedia.
Propeller.
[Online]
http://en.wikipedia.org/wiki/Propeller.
[Cited:
Jun
01,
2008.]
26. IVOPROP CORP. [Online] [Cited: Jun 01, 2008.] http://www.ivoprop.com/.
27. Wikipedia. Wikipedia - Fuel Cell. [Online] [Cited: Jun 01, 2008.]
28. Atomstromfreie. Solar powered aircrafts. [Online] [Cited: May 31, 2008.]
http://www.pvresources.com/en/helios.php.
29. Global Aircraft. Global Aircraft -- Helios. [Online] [Cited: May 31, 2008.]
http://www.globalaircraft.org/planes/helios.pl.
30. Ibiblio.org. Homepower Magazine - Alternative Energy. [Online] [Cited: May 31, 2008.]
http://www.ibiblio.org/ecolandtech/alternative-energy/homepowermagazine/archives/19/19pg08.txt.
31. SAFT Battery Company. [Online] http://www.saftbatteries.com.
32. Kokam CO. Ltd. [Online] http://www.kokamamerica.com/,.
33. Stefan Vorkoetter. Stefan's Electric R/C Web Site. [Online] [Cited: May 25, 2008.]
http://www.stefanv.com/rcstuff/.
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Page 53
APPENDIX A
Commercially available fuel cell products:
http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/fuel_cell_products.pdf
http://www.fuelcells.org/usfccproductlist.pdf
http://www1.eere.energy.gov/hydrogenandfuelcells/fuelcells/fc_types.html
Battery powered aircraft:
http://www.aeroconversions.com/e-flight/electric.html
http://www.youtube.com (Sonex Electric Powered Flight)
http://www.lightsportaircraft.ca/airventure-2006/electricpoweredpoweredparaglider.html
Page 1
APPENDIX B
This section contains meeting agendas and minutes we had during the development of
project. They are presented in chronological order.
Meeting Minutes
Meeting Purpose: (Describe Below)
Schedule Date: 3/30/08
The objective is to come away from the meeting with:
1. A list of identified customer needs;
2. Who are the stakeholders;
Preparation – Each member should come with an idea of who the stakeholders are and
research on some common systems for energy concept.
Agenda Item Description
Start Time: 1pm
End Time: 2pm
Discussion
Time Allotted
Leader
5 min
30min
Brad
1. Welcome
2. Present and discussion of customer
needs
3. Identified the stakeholders in the
15min
project
4. Meeting close
5min
Total Time = 55mins
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
All
Objective
Discussion
Information
Decision
Page 2
Meeting Minutes
Meeting Purpose: (Describe Below)
Schedule Date: 4/6/08
The objective is to come away from the meeting with:
1. Customers needs in relation to the our subsystem
2. Discuss research on existing modes energy conversion, storage and propulsion.
Preparation – Each member should come with a list of how the needs are related to
the needs of the subsystem and research material on some common systems for
energy concept.
Agenda Item Description
Start Time: 1pm
End Time: 2:45pm
Discussion
Time Allotted
Leader
5 min
45min
Brad
1. Welcome
2. Discussion of how customer needs
relates to subsystem
3. Review the concepts of all the
50min
research performed
4. Meeting close
5min
Total Time = 105mins
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
All
Objective
Discussion
Discussion
Information
Page 3
Meeting Minutes
Meeting Purpose: (Describe Below)
Schedule Date: 4/13/08
Discussion of subsystem functional decomposition and needs. The objective is to come
away from the meeting with:
1.
2.
3.
4.
An agreed functional decomposition.
Sub-sub system allocations to group members for assignments 3.
A list of agreed subsystem needs, with relative, for the sub-system, and
A list of metrics against those needs.
Preparation – Each member should come with a functional decomposition for the subsystem for discussion in item 2; and a list of sub-system needs for discussion in item 6.
Agenda Item Description
Start Time: 1pm
End Time: 3pm
Discussion
Time Allotted
Leader
5 min
20min
Pouyan
1. Welcome
2. Present and discussion functional
decomposition
3. Decide on group functional
5min
decomposition
4. Discuss function allocation with
10min
group
5. Allocate functions to group member 5min
6. Review and discuss subsystem needs 30min
7. Allocate importance (reference
15min
textbook)
8. Establish a list of metrics
15min
9. Discuss next meeting
10min
10. Meeting close
5min
Total Time = 120mins
Objective
Discussion
Information
All
Decision
Brad
Discussion
Brad
Mauricio
Mauricio
Decision
Discussion
Decision
Terence
Brad
Decision
Discussion
Meeting Minutes
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Page 4
Meeting Purpose: (Describe Below)
Schedule Date: 4/20/08
The objective is to come away from the meeting with:
1. concept chosen
2. allocate group members with the special concept
3. A list of agreed subsystem needs, with relative importance
Preparation – Each member should come with a concept for aircraft.
Agenda Item Description
Start Time: 1pm
End Time: 3pm
Discussion
Time Allotted
Leader
5 min
30min
All
1. Welcome
2. Present and discussion energy
storage metrics matrix
3. Discuss the concepts that everyone
25min
came up with
4. Allocate group members with the
10min
special concept
5. Discuss the concept classification
20min
tree
6. Review and discuss subsystem
30min
needs, discuss next meeting
Total Time = 120mins
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Objective
Discussion
Discussion
All
Decision
Brad
Discussion
All
Decision
Mauricio
Discussion
Page 5
Meeting Minutes
Meeting Purpose: (Describe Below)
Schedule Date: 4/27/08
The objective is to come away from the meeting with:
1. concept analysis
2. allocate different concept analysis to everyone
3. need-matrix
Preparation – need matrix. Concept tree for energy storage system. Concept tree for
energy generation system.
Agenda Item Description
1. Welcome
2. Hybrid Drive
3. Electric with rocket assisted take off
4. Nuclear powered aircraft
5. Diesel Powered aircraft
6. Solar powered and solar powered
with battery assistance
Start Time: 1pm
End Time: 2:40pm
Discussion
Time Allotted
Leader
5 min
10min
Brad
10min
Brad
10min
Xuefeng,Ye
10min
Terence
Discussion
Information
Information
Information
Information
10min
Terence
Information
Terence
Information
Mauricio
Information
Mauricio
Nan Yi
Information
Information
7. Fuel cell powered with battery
10min
assisted takeoff
8. Conventional internal combustion
10min
engine
9. Jet engine
10min
10. regenerative braking
10min
11. meeting close
5min
Total Time = 100mins
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Objective
Page 6
Meeting Minutes
Meeting Purpose: (Describe Below)
Schedule Date: 5/03/08
The objective is to come away from the meeting with:
1. concept detailed specification
2. allocate different concept to everyone
Start Time: 1pm
End Time: 2:30pm
Discussion
Agenda Item Description
Time Allotted
Leader
1. Welcome
5 min
2. Review concepts
20min
All
3. Specifications for different concept
20min
All
4. Templates for specifications
20min
All
5. Allocate concepts to everyone
10min
All
6. Meeting close
15min
Total Time = 90mins
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Objective
Discussion
Discussion
Discussion
Discussion
Discussion
Page 7
Meeting Minutes
Meeting Purpose: (Describe Below)
Schedule Date: 5/06/08
The objective is to come away from the meeting with:
1. Develop a comprehensive list of concepts
2. Some structure concept generation within the group
3. Some initial concept screening with possible recommendations for the whole
group
4. Integration opportunities between your sub system and others
Preparation: templates for concepts information.
Start Time: 2pm
End Time: 3:30pm
Discussion
Agenda Item Description
Time Allotted
Leader
1. Welcome
5 min
2. Templates for concepts information 20min
All
3. Structure concept generation
20min
All
4. A comprehensive list of concepts
20min
All
5. Integration opportunities
20min
All
6. Meeting close
5min
Total Time = 90mins
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Objective
Discussion
Discussion
Discussion
Discussion
Discussion
Page 8
Meeting Minutes
Meeting Purpose: (Describe Below)
Schedule Date: 5/07/08
The objective is to come away from the meeting with:
1. Set different tasks about power vs. weight; cost vs. power; Flight time vs. cost;
Flight time vs. power; Flight time vs. weight.
2. Allocate tasks.
Start Time: 4pm
End Time: 4:40pm
Discussion
Agenda Item Description
Time Allotted
Leader
1. Set tasks about conduct analysis
10 min
Brad
2. Allocate different to everyone
15min
All
3. Decide next meeting
10min
All
4. Meeting close
5min
Total Time = 40mins
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Objective
Discussion
Discussion
Discussion
Page 9
Meeting Minutes
Meeting Purpose: (Describe Below)
Schedule Date: 5/19/08
The objective is to come away from the meeting with:
1. Discuss concept analysis based on conduct analysis
2. Discuss life cycle analysis on internal combustion engine and electric motor
Preparation: conduct analysis.
Start Time: 4pm
End Time: 6:10pm
Discussion
Agenda Item Description
Time Allotted
Leader
1. Welcome
5 min
2. Analysis of Weight vs. Power, Cost 20min
Mauricio
vs. Power for Hybrid engine, Internal
combustion engine, Electric motor
3. Analysis of Weight vs. Power and
20min
Pouyan
Cost vs. Power for Wind regeneration,
regenerative braking, solar cells
4. Analysis of Flight Time vs. Weight;
20min
Terence
Flight Time vs. Cost; and Flight Time vs.
Power for Hybrid engine, Internal
combustion engine, Electric motor
5. Analysis of Flight Time vs. Weight;
20min
Nan Yi
Flight Time vs. Cost; and Flight Time vs.
Power for Wind regeneration,
regenerative braking, solar cells
6. A life cycle analysis of an internal
20min
Ming Chen
combustion engine system
7. A life cycle analysis of an electric
20min
Xuefeng,Ye
power system
8. Meeting close
5min
Total Time = 130mins
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Objective
Discussion
Information
Information
Information
Information
Information
Information
Page 10
Meeting Minutes
Meeting Purpose: (Describe Below)
Schedule Date: 5/26/08
The objective is to come away from the meeting with:
1. Discuss cost vs. weight/power for internal combustion engine, electric motor
2. Information about propeller.
Agenda Item Description
Start Time: 4pm
End Time: 5pm
Discussion
Time Allotted
Leader
5 min
All
30min
All
1. Welcome
2. Discuss tasks about comparison for
internal combustion engine and
electric motor
3. Allocate tasks
10min
4. Discuss next meeting
10min
5. Meeting close
5min
Total Time = 60mins
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Pouyan
All
Objective
Discussion
Discussion
Discussion
Discussion
Page 11
Meeting Minutes
Meeting Purpose: (Describe Below)
Schedule Date: 5/27/08
The objective is to come away from the meeting with:
1. Discuss cost vs. weight/power for internal combustion engine, electric motor
2. Comparison about internal combustion engine and electric motor.
3. Discuss propeller
Start Time: 6pm
End Time: 6:50pm
Discussion
Agenda Item Description
Time Allotted
Leader
1. Welcome
5 min
All
2. Discuss cost vs. weight/power
20min
All
3. Discuss propeller
20min
Ming Chen
4. Meeting close
5min
All
Total Time = 50mins
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Objective
Discussion
Discussion
Discussion
Discussion
Page 12
Meeting Minutes
Meeting Purpose: Completion of Formal Report
Schedule Date: 6/2/08
The objective is to:
1. To compile and check the status of the report.
2. Include any missing information on the various assigned tasks
Start Time: 4pm
End Time: 7pm
Discussion
Agenda Item Description
Time Allotted
Leader
1. Discuss the work done
30min
All
2. Gather additional data
90min
All
3. Compile the report
30
All
Total Time = 180mins
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Objective
Discussion
Information
Discussion
Page 13
Meeting Minutes
Meeting Purpose: Report Writing
Schedule Date: 5/31/08
The objective is to:
1.
2.
3.
4.
Plan the outline of the report.
Distribute the work to teams of 2.
Gather information.
Write the report
Agenda Item Description
Start Time: 10am
End Time: 7pm
Discussion
Time Allotted
Leader
5 min
All
20min
1. Welcome
2. Discuss and plan the scope and
layout of the report.
3. Work is distributed to teams based
5min
on the sub sub-system
4. Introduction, Abstract and
Benchmarking
5. Customer needs and benchmarking
6.Functional decomposition
8hrs
7. Concept generation and research
8. Concept Screening
9. Concept development and
Description
10. Future Recommendations
30mins
Total Time = 9hrs
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Objective
Discussion
Discussion
All
Decision
Terence
Writing
Mauricio
Ming Chen
Brad
Pouyan
All
Writing
Writing
Writing
Writing
Writing
All
Writing
Page 14
Meeting Minutes
Meeting Purpose: Completion Final Presentation Slides Schedule Date: 6/3/08
The objective is to:
1. Review the Project Report
2. Compilation slides for the final presentation based on report generated
3. Prepare for presentation.
Agenda Item Description
1. Look through the report and
identify areas for improvement
2. Compile slides for presentation
3. Going through the presentation
slides
Start Time: 2pm
End Time: 9pm
Discussion
Time Allotted
Leader
1hrs
Mauricio
4hr 30mins
1hr 30min
Pouyan
Brad
Objective
Discussion
Decision
Information
Total Time =7hrs
ENGN 8100: INTRODUCTION TO SYSTEMS ENGINEERING
FINAL REPORT
Page 15