Download - TIM PENYUSUN - idu.ac.id
i
TIM PENYUSUN
Penyadur : Sovian Aritonang
Editor : Ridho Illahi Putra
ii
KATA PENGANTAR
Puji syukur kehadirat Allah SWT atas limpahan rahmat dan
karunianya sehingga Buku Bahan Ajar MK. Military Platform Design Prodi
Teknologi Daya Gerak Fakultas Teknologi Pertahanan Universitas
Pertahanan telah dapat diselesaikan. Buku bahan ajar ini merupakan
penyempurnaan dari edisi sebelumnya, sebagai bahan ajar bagi
mahasiswa Program Studi Prodi Teknologi Daya Gerak Fakultas
Teknologi Pertahanan Universitas Pertahanan agar mahasiswa
mendapatkan gambaran secara jelas mengenai MK. Military Platform
Design.
Program Belajar Mengajar di Fakultas Teknologi Pertahanan
ditujukan untuk memenuhi prinsip-prinsip pokok yang terkandung dalam
Paradigma Baru Penataan Pendidikan Tinggi di Indonesia. Paradigma
baru tersebut meliputi 5 (lima) prinsip yaitu: kualitas, otonomi, akuntabilitas
/ pertanggungjawaban, akreditasi dan evaluasi. Selain lima prinsip
tersebut, maka aspek inovasi dan kreatifitas juga menjadi karakteristik
yang melekat dalam seluruh kegiatan mendukung Program Belajar
Mengajar.
Buku Bahan Ajar ini diharapkan dapat menjadi salah satu sumber
acuan yang dapat dipakai di dalam keseluruhan rangkaian aktivitas
Pembelajaran, evaluasi keberhasilan studi, Kuliah Kerja Dalam Negeri
(KKDN), Kuliah Kerja Luar Negeri (KKLN), tugas akhir, administrasi
perkuliahan dan kurikulum. Buku pedoman ini, wajib digunakan oleh
semua pihak yang berperan seperti dosen, mahasiswa, dan tenaga
kependidikan sehingga dapat terlaksana dengan efisien dan efektif.
Kepada semua pihak yang berkontribusi dalam penyusunan buku
bahan ajar ini, pimpinan fakultas menyampaikan terima kasih dan
penghargaan yang sebesar-besarnya.
Sesprodi
Teknologi Daya Gerak,
Dr. Sovian Aritonang, S.Si., M.Si
Kolonel Kes. NRP. 519726
iii
DAFTAR ISI
DAFTAR ISI ........................................................................................... i
KATA PENGANTAR ............................................................................... ii
DAFTAR ISI ............................................................................................ iii
PERTEMUAN 1 Operasional Environment.............................................. 1
1.1 Pendahuluan .......................................................................... 1
1.2 Tujuan Instruksional Umum .................................................... 1
1.3 Tujuan Instruksional Khusus................................................... 1
1.4 Skenario Pembelajaran .......................................................... 1
1.5 Ringkasan Materi ................................................................... 2
1.5.1 The Constants ...................................................... 2
1.5.2 Trends Influencing the World’s Security ................ 6
1.5.3 The Implications for the Joint Force War in the the
Twenty-First Century ............................................ 10
1.5.4 Preparing for War ................................................. 12
1.5.5 The Conduct of Military Operations in the Twenty
First Century ......................................................... 17
PERTEMUAN 2 Naval Ship Design ........................................................ 21
2.1 Pendahuluan .......................................................................... 21
2.2 Tujuan Instruksional Umum .................................................... 21
2.3 Tujuan Instruksional Khusus................................................... 21
2.4 Skenario Pembelajaran .......................................................... 21
2.5 Ringkasan Materi ................................................................... 22
2.5.1 History of Structural Design-Comercial VS Naval .. 22
2.5.2 Recent Trends in Naval Vessel Design ................. 27
iv
2.5.3 Naval Structural Design Philosophy ...................... 29
2.5.4 External Blast Events ............................................ 32
PERTEMUAN 3 Military and Commercial Shipbuilding ........................... 35
3.1 Pendahuluan .......................................................................... 35
3.2 Tujuan Instruksional Umum .................................................... 35
3.3 Tujuan Instruksional Khusus................................................... 35
3.4 Skenario Pembelajaran .......................................................... 35
3.5 Ringkasan Materi ................................................................... 35
3.5.1 Shipbuilding Trends .............................................. 35
3.5.2 Differences Between Military and Commercial
Shipbuilding .......................................................... 36
3.5.3 Prospects for Market Entry an Integration ............. 37
3.5.4 The Way Forward ................................................. 39
PERTEMUAN 4 Introduction to Aircraft Stability ..................................... 42
4.1 Pendahuluan .......................................................................... 42
4.2 Tujuan Instruksional Umum .................................................... 42
4.3 Tujuan Instruksional Khusus................................................... 42
4.4 Skenario Pembelajaran .......................................................... 42
4.5 Ringkasan Materi ................................................................... 42
4.5.1 Aerodynamic Controls .......................................... 42
4.5.2 Atmospheric Properties ......................................... 44
4.5.3 Aerodynamic Background ..................................... 44
v
PERTEMUAN 5 Konsep Struktur Fighter ............................................... 49
5.1 Pendahuluan .......................................................................... 49
5.2 Tujuan Instruksional Umum .................................................... 49
5.3 Tujuan Instruksional Khusus................................................... 49
5.4 Skenario Pembelajaran .......................................................... 49
5.5 Ringkasan Materi ................................................................... 49
5.5.1 Struktur Analysis ................................................... 49
5.5.2 Structure & Payload Design .................................. 52
PERTEMUAN 6 Introdouction To Fighter ................................................ 59
6.1 Pendahuluan .......................................................................... 59
6.2 Tujuan Instruksional Umum .................................................... 59
6.3 Tujuan Instruksional Khusus................................................... 59
6.4 Skenario Pembelajaran .......................................................... 59
6.5 Ringkasan Materi ................................................................... 60
6.5.1 Kompetensi Dalam Pengembangan Pesawat
Terbang ................................................................ 60
6.5.2 Airplane Integration .............................................. 62
PERTEMUAN 7 Propulsion ................................................................... 68
7.1 Pendahuluan .......................................................................... 68
7.2 Tujuan Instruksional Umum .................................................... 68
7.3 Tujuan Instruksional Khusus................................................... 68
7.4 Skenario Pembelajaran .......................................................... 68
7.5 Ringkasan Materi ................................................................... 68
7.5.1 Propulsion analysis ............................................... 69
7.5.2 Propulsion Integration ........................................... 70
PERTEMUAN 8 UTS ............................................................................. 77
vi
PERTEMUAN 9 Structural, Design and Analysis ................................... 78
9.1 Pendahuluan .......................................................................... 78
9.2 Tujuan Instruksional Umum .................................................... 78
9.3 Tujuan Instruksional Khusus................................................... 78
9.4 Skenario Pembelajaran .......................................................... 78
9.5 Ringkasan Materi ................................................................... 78
9.5.1 State of the Art ...................................................... 78
9.5.2 Scope of the work ................................................. 86
9.5.3 Limitations ............................................................ 89
9.5.4 The method........................................................... 91
PERTEMUAN 10 Marine Propulsion ...................................................... 93
10.1 Pendahuluan ........................................................................ 93
10.2 Tujuan Instruksional Umum .................................................. 93
10.3 Tujuan Instruksional Khusus ................................................. 93
10.4 Skenario Pembelajaran ........................................................ 93
10.5 Ringkasan Materi ................................................................. 94
10.5.1 Propulsion Systems ............................................ 94
10.5.2 Matching Engines and Watercrafts ..................... 105
10.5.3 Wave resistance ................................................. 106
10.5.4 Submarines ........................................................ 108
PERTEMUAN 11 Avionics, Navigation, and Instrumention ..................... 112
11.1 Pendahuluan ........................................................................ 112
11.2 Tujuan Instruksional Umum .................................................. 112
11.3 Tujuan Instruksional Khusus ................................................. 112
11.4 Skenario Pembelajaran ........................................................ 112
11.5 Ringkasan Materi ................................................................. 112
vii
11.5.1 Avionics System Patterned After Apollo;
Features and Capabilities Unlike Any Other
in the Industry .................................................... 112
11.5.2 Central Processor Units Were Available Off the
Shelf—Remaining Hardware and Software
Would Need to be Developed ............................. 115
PERTEMUAN 12 Jet Fighter Aircraft ..................................................... 124
12.1 Pendahuluan ........................................................................ 124
12.2 Tujuan Instruksional Umum .................................................. 124
12.3 Tujuan Instruksional Khusus ................................................. 124
12.4 Skenario Pembelajaran ........................................................ 124
12.5 Ringkasan Materi ................................................................. 124
12.5.1 Jet fighter aircraft ................................................ 124
12.5.2 A Brief History of the Development of Jet Fighter
Aircraft ................................................................. 127
12.5.3 First Generation Jet Fighters ............................... 129
12.5.4 Second Generation Jet Fighters.......................... 130
12.5.5 Third Generation Jet Fighter ............................... 131
PERTEMUAN 13 Flotation, hydrostatics, and ship stability ..................... 133
13.1 Pendahuluan ........................................................................ 133
13.2 Tujuan Instruksional Umum .................................................. 133
13.3 Tujuan Instruksional Khusus ................................................. 133
13.4 Skenario Pembelajaran ........................................................ 133
13.5 Ringkasan Materi ................................................................. 133
13.5.1 Flotation, hydrostatics, and ship stability ............ 133
13.5.2 Archimedes priciple ............................................ 135
viii
13.5.3 The gentle art of ballooning ................................. 137
13.5.4 Stability of Floating bodies .................................. 139
PERTEMUAN 14 Fundamentals of Systems Engineering....................... 145
14.1 Pendahuluan ........................................................................ 145
14.2 Tujuan Instruksional Umum .................................................. 145
14.3 Tujuan Instruksional Khusus ................................................. 145
14.4 Skenario Pembelajaran ........................................................ 145
14.5 Ringkasan Materi ................................................................. 145
14.5.1 Design Solution Definition Process ..................... 145
14.5.2 Multidisclinary Design Optimization ..................... 148
14.5.4 Concurrent design approach ............................... 154
PERTEMUAN 15 Studi Kasus ............................................................... 159
PERTEMUAN 16 UAS ............................................................................ 160
1
PERTEMUAN 1
Operasional Environment
1.1. Pendahuluan
Pokok bahasan materi dalam pertemuan 1 terdiri dari:
a. The Constants
b. Trends Influencing The World‘s Security
c. The Contextual World
d. The Implications for the Joint Force
e. Some Leading Questions
1.2. Tujuan Instruksional Umum
Setelah mempelajari pokok bahasan materi 1, mahasiswa mampu
memahami The Constants, Trends Influencing The World‘s
Security,The Contextual World,The Implications for the Joint Force,
Some Leading Questions
1.3. Tujuan Instruksional Khusus
Setelah mempelajari pokok bahasan materi 1, mahasiswa mampu
menjelaskan The Constants, Trends Influencing The World‘s
Security,The Contextual World,The Implications for the Joint Force,
Some Leading Questions
1.4. Skenario Pembelajaran
a. Dosen menjelaskan silabus kuliah, aturan kuliah, dan sistem
penilaian
b. Dosen menjelaskan materi kuliah
c. Diskusi dan tanya jawab dengan mahasiswa
d. Pembagian kelompok
e. Evaluasi pencapaian belajar
2
1.5. Ringkasan Materi:
1.5.1 The Constants
We cannot predict exactly what kind of war, or for what
purposes, the armed forces of the United States will find
themselves engaged in over the next quarter century. We can
only speculate about possible enemies and the weapons they
will bring to the fight. But we can state with certainty that the
fundamental nature of war will not change. In a democracy
such as the United States, political aims, pressures, and
hesitations have always conditioned military operations – and
will continue to do so. ―When whole communities go to war...
the reason always lies in some political situation.‖5 War is a
political act, begun for political purposes. In the twenty-first
century war will retain its political dimension, even when it
originates in the actions of non-state and transnational groups.
The Joint Force will operate in an international environment
where struggle predominates. While the origins of war may
rest on policy, a variety of factors has influenced the conduct
of that struggle in the past and will do so in the future. The
tension between rational political calculations of power on one
hand and secular or religious ideologies on the other,
combined with the impact of passion and chance, makes the
trajectory of any conflict difficult if not impossible to predict. In
coming decades, Americans must struggle to resist judging
the world as if it operated along the same principles and
values that drive our own country. In many parts of the world,
there are no rational actors, at least in our terms. Against
enemies capable of mobilizing large numbers of young men
and women to slaughter civilian populations with machetes or
to act as suicide bombers in open markets; enemies eager to
die, for radical ideological, religious, or ethnic fervor; enemies
who ignore national borders and remain unbound by the
3
conventions of the developed world; there is little room for
negotiations or compromise. It can become a matter of
survival when human passion takes over. Such a world has
existed in recent history – in World War II on the Eastern Front
and on the islands of the Pacific, in Africa in the Rwandan
genocide, and to some extent in Iraq. In a world where
passions dominate, the execution of rational strategy becomes
extraordinarily difficult.
War more than any other human activity engages our
senses: at times providing a ―rush‖ of fear, horror, confusion,
rage, pain, helplessness, nauseous anticipation, and hyper-
awareness. It is in these vagaries that imponderables and
miscalculations accumulate to paralyze the minds of military
and political leaders. In the cauldron of war, ―It is the
exceptional [human being] who keeps his powers of quick
decision intact.
There are other aspects of human conflict that will not
change no matter what advances in technology or computing
power may occur: fog and friction will distort, cloak, and twist
the course of events. Fog will result from information overload,
our own misperceptions and faulty assumptions, and the fact
that the enemy will act in an unexpected fashion. Combined
with the fog of war will be its frictions - that almost infinite
number of seemingly insignificant incidents and actions that
can go wrong, the impact of chance, and the horrific effect of
combat on human perceptions. It will arise ―from fundamental
aspects of the human condition and unavoidable
unpredictabilities that lie at the very core of combat
processes.‖71
It is the constant fog and friction of war that turn the simple
into the complex. In combat, people make mistakes. They
4
forget the basics. They become disoriented, ignoring the vital
to focus on the irrelevant. Occasionally, incompetence
prevails. Mistaken assumptions distort situational awareness.
Chance disrupts, distorts, and confuses the most careful of
plans. Uncertainty and unpredictability dominate. Thoughtful
military leaders have always recognized that reality, and no
amount of computing power will eradicate this basic
messiness.
Where friction prevails, tight tolerances, whether applied to
plans, actions, or materiel are an invitation to failure – the
more devastating for being unexpected. Operational or
logistical concepts or plans that make no allowance for the
inescapable uncertainties of war are suspect on their face –
an open invitation to failure and at times defeat.
Still another enduring feature of conflict lies in the recurring
fact that military leaders often fail to recognize their enemy as
a learning, adaptive force. War ―is not the action of a living
force upon a lifeless mass...
but always the collision of two living forces.‖8 Those living
forces possess all the cunning and intractable characteristics
human beings have enjoyed since the dawn of history.
Even where adversaries share a similar historical and
cultural background, the mere fact of belligerence guarantees
profound differences in attitudes, expectations, and behavioral
norms. Where different cultures come into conflict, the
likelihood that adversaries will act in mutually
incomprehensible ways is even more likely. Thus, ―if you know
the enemy and know yourself you need not fear the results of
a hundred battles.‖9 The conduct of war demands a deep
5
understanding of the enemy – his culture, history, geography,
religious and ideological motivations, and particularly the huge
differences in his perceptions of the external world. The
fundamental nature of war will not change.
The Nature of Change
If war will remain a human endeavor, a conflict between two
learning and adapting forces, changes in the political
landscape, adaptations by the enemy, and advances in
technology will change the character of war. Leaders are often
late to recognize such changes. Driven by an inherent desire
to bring order to a disorderly, chaotic universe, human beings
tend to frame their thoughts about the future in terms of
continuities and extrapolations from the present and
occasionally the past. But a brief look at the past quarter
century, to say nothing of the past four thousand years,
suggests the extent of changes that coming decades will
bring. Twenty-five years ago the Cold War encompassed
every aspect of the American military‘s thinking and
preparation for conflict – from the strategic level to the tactical.
Today, that all-consuming preoccupation is an historical relic.
A quarter century ago, the United States confronted the Soviet
Union, a truculent, intractable opponent with leaders firmly
committed to the spread of Marxist-Leninist ideology and
expansion of their influence. At that time, few in the
intelligence communities or even among Sovietologists
recognized the deepening internal crisis of confidence that
would lead to the implosion of the Soviet Empire. The
opposing sides had each deployed tens of thousands of
nuclear weapons, as well as vast armies, air forces, and
navies across the globe. Soviet forces were occupying
Afghanistan and appeared on the brink of crushing an uprising
6
of ill-equipped, ill-trained guerrillas. In El Salvador, a Soviet-
backed insurgency was on the brink of victory.
Beyond the confrontation between the United States and
Soviet Union lay a world that differed enormously from today.
China was only emerging from the dark years of Mao‘s rule.
To China‘s south, India remained mired in an almost medieval
level of poverty, from which it appeared unlikely to escape. To
the sub-continent‘s west, the Middle East was as plagued by
political and religious troubles as today. But no one could have
predicted then that within 25 years the United States would
wage two major wars against Saddam Hussein‘s regime and
commit much of its ground power to suppressing simultaneous
insurgencies in Iraq and Afghanistan.
The differences between the culture and organization of the
American military then and now further underline the extent of
the disruptions with the past. The lack of coordination among
the forces involved in overthrowing the ―New Jewel‖
movement in Grenada in October 1983 reminds us that at the
time jointness was a concept honored more in the breach than
observance. That situation led to the Goldwater-Nichols Act in
1986.
In terms of capabilities, stealth did not yet exist outside of
the research and development communities. The M-1 Tank
and the Bradley Fighting Vehicle were only starting to reach
the Army‘s forward deployed units.
1.5.2 Trends Influencing the World’s Security
Trend analysis is the most fragile element of forecasting.
The world‘s future over the coming quarter of a century will be
subject to enormous disruptions and surprises, natural as well
as man-made. These disruptions, and many other contiguous
7
forces, can easily change the trajectory of any single trend.
The Joint Operating Environment recognizes that many, if not
all, of the trends and trajectories of the future will be non-
linear. But for the purpose of analysis, it has used a traditional
approach to examine many of the trends and utilized
conservative estimates. For instance, demographically, it has
used estimates from sources such as the U.S. Census
Bureau. Economically, the Joint Operating Environment
assumes growth rates for developed countries of 2.5% and
4.5% for developing countries, including China. It is in this
manner that this study considers the trends below. In the final
analysis, the value of the trends lies not in accurately
predicting them, but in intuiting how they might combine in
different ways to form more enduring contexts for future
operations. Trend analysis can also help in identifying some
indicators or signposts that one can use to ―check‖ the path
that the world takes into the future and make adjustments as
necessary. Nevertheless, the resource and strategic
implications of even a conservative and linear rate of increase
possess consequences that suggest a dark picture of the
future.
Demograpihics
A good place to begin the discussion of trends is
demographics, because what is happening demographically
today, unless altered by some catastrophe, has predictable
consequences for the populations of regions and states.
Equally important, it possesses implications for future strategic
postures and attitudes. In total, the world will add
approximately 60 million people each year and reach a total of
8 billion by the 2030s. Ninety-five percent of that increase will
occur in developing countries. The more important point is that
the world‘s troubles will occur not only in the areas of abject
8
poverty, but also to an even greater extent in developing
countries, where the combination of demographics and
economy permits populations to grow, but makes meeting
rising expectations difficult. Here, the performance of the
global economy will be key in either dampening down or
inflaming ethnically or religiously-based violent movements.
The developed world confronts the opposite problem.
During the next 25 years population growth in the developed
world will likely slow or in some cases decline. In particular,
Russia‘s population is currently declining by 0.5% annually,
and given Russian health and welfare profiles, there is every
prospect that decline will continue, barring a drastic shift in
social attitudes or public policy. As a recent Center for
Strategic International Studies (CSIS) report suggested,
―Russia needs to cope with a rate of population decline that
literally has no historical precedent in the absence of
pandemic.‖131 To Russia‘s west, a similar, albeit less
disastrous situation exists. Over all, European nations stopped
replacing their losses to deaths in 2007, and despite
considerable efforts to reverse those trends, there is little
likelihood their populations will significantly increase by the
2030s. This raises serious concerns about the sustainability of
economic growth in that region. It also has serious
implications for the willingness of European societies to bear
the costs involved in lives and treasure that the use of military
force inevitably carries with it.
Likewise, Japan‘s population will fall from 128 million to
approximately 117 million in the 2030s, but unlike the case of
Russia this will result not from any inadequacy of Japanese
medical services, which are among the world‘s best, but from
the collapse of Japan‘s birth rate. The Japanese are taking
serious steps to address their demographic decline, a fact
9
which explains their major research and development efforts
in the field of robotics as well as their shift to a capital-
intensive economy.
Globalitation
For the most part, the developed world recognizes that it has a
major stake in the continuing progress of globalization. The
same can be said for those moving into the developed world.
Nevertheless, one should not ignore the histories and
passions of popular opinion in these states as they make their
appearance. One should not confuse developed world
trappings for an underlying stability and maturity of civil
societies. A more peaceful cooperative world is only possible if
the pace of globalization continues. In particular, this means
engaging China and other nations politically and culturally as
they enter into the developed world.
The critics of globalization often portray its dark side in the
inequality of rich and poor. In some worst -case scenarios,
they portray the rise of resentment and violence throughout
the world as a direct result of globalization. Not surprisingly,
the future is likely to contain both good and bad as
globalization accelerates the pace of human interaction and
extends its reach
Energy
To meet even the conservative growth rates posited
above, global energy production would need to rise by 1.3%
per year. By the 2030s, demand would be nearly 50% greater
than today. To meet that demand, even assuming more
effective conservation measures, the world would need to add
roughly the equivalent of Saudi Arabia‘s current energy
production every seven years.
10
Unless there is a major change in the relative reliance on
alternative energy sources, which would require vast
insertions of capital, dramatic changes in technology, and
altered political attitudes toward nuclear energy, oil and coal
will continue to drive the energy train. By the 2030s, oil
requirements could go from 86 to 118 million barrels a day
(MBD). Although the use of coal may decline in the
Organization for Economic Cooperation and Development
(OECD) countries, it will more than double in developing
nations. Fossil fuels will still make up 80% of the energy mix in
the 2030s, with oil and gas comprising upwards of 60%. The
central problem for the coming decade will not be a lack of
petroleum reserves, but rather a shortage of drilling platforms,
engineers and refining capacity. Even were a concerted effort
begun today to repair that shortage, it would be ten years
before production could catch up with expected demand. The
key determinant here would be the degree of commitment the
United States and others would display in addressing the
dangerous vulnerabilities the growing energy crisis presents
1.5.3 The Implications for the Joint Force War in the the Twenty-
First Century
As the discussion of trends and contexts above has
suggested, the roles and missions of the Joint Force will
include the protection of the homeland, the maintenance of the
global commons, the deterrence of potential enemies, and,
when necessary, fighting and winning conflicts that may occur
around the world. Such challenges are by themselves
daunting enough, but they will occur in a period characterized
by radical technological, strategic, and economic change, all
of which will add to the complexities of the international
environment and the use of military force. America‘s position
11
in the world, unprecedented in almost every respect, will
continue to present immense challenges to its military forces.
Rapidly changing trends within the contexts described in the
previous section will have profound implications for the
character of war itself and the methods by which the Joint
Force will wage it. Yet, the nature of war will remain closer to
Agincourt than to Star Trek. At its heart, war will always
involve a battle between two creative human forces. Our
enemies are always learning and adapting. They will not
approach conflicts with conceptions or understanding similar
to ours. And they will surprise us. No amount of technology,
conceptualization, or globalization will change those realities.
Moreover, the employment of military force will continue to be
conditioned by politics -- not only those of the United States
and its allies, but by those of its opponents. Above all, joint
force commanders, their staffs, and their subordinates must
have a clear understanding of the strategic and political goals
for which they conduct military operations. In almost every
case, they will find themselves working closely with partners, a
factor which will demand not only a thorough understanding of
U.S. political goals, but coalition goals as well.
It is in this political-strategic environment that the greatest
surprises for Americans may come. The United States has
dominated the world economically since 1915and militarily
since 1943. Its dominance in both respects now faces
challenges brought about by the rise of powerful states.
Moreover, the rise of these great powers creates a strategic
landscape and international system, which, despite continuing
economic integration, will possess considerable instabilities.
Lacking either a dominant power or an informal organizing
framework, such a system will tend toward conflict. Where and
12
how those instabilities will manifest themselves remains
obscure and uncertain.
Between now and the 2030s, the military forces of the United
States will almost certainly find themselves involved in
combat. Such involvement could come in the form of a major
regular conflict or in a series of wars against insurgencies.
And as this document has suggested, they will certainly find
themselves engaged not only against terrorist organizations,
but against those who sponsor them. One of the great
problems that confronts American strategists and military
planners is the conundrum of preparing for wars that remain
uncertain as to their form, location, level of commitment, the
contribution of potential allies, and the nature of the enemy.
The only matter that is certain is that joint forces will find
themselves committed to conflict against the enemies of the
United States and its Allies, and in defense of its vital
interests.
1.5.4 Preparing for War
There are two ominous scenarios that confront joint forces
between now and the 2030s. The first and most devastating
would be a major war with a powerful state or hostile alliance
of states. Given the proliferation of nuclear weapons, there is
the considerable potential for such a conflict to involve the use
of such weapons. While major regular war is currently in a
state of hibernation, one should not forget that in 1929 the
British government adopted as its basic principle of defense
planning the assumption that no major war would occur for the
next ten years. Until the mid-1930s ―the ten year rule‖ crippled
British defense expenditures. The possibility of war remained
inconceivable to British statesmen until March 1939.
13
The one approach that would deter a major conflict involving
U.S. military forces, including a conflict involving nuclear
weapons, is the maintenance of capabilities that would allow
the United States to wage and win any possible conflict. As
the Romans so aptly commented, ―if you wish for peace,
prepare for war.‖ Preventing war will in most instances prove
more important than waging it. In the long-term, the primary
purpose of the military forces of the United States must be
deterrence, for war in any form and in any context is an
immensely expensive undertaking both in lives and national
treasure. When, however, deterrence fails, then, the military
effectiveness of those forces will prove crucial. Here the
efforts that have gone into preparing U.S. forces for conflict at
their various training centers must continue to receive the
same support and attention in the future that they have over
the course of the past 30 years. As the Japanese
warrior/commentator Miyamoto Musashi noted in the
seventeenth century:
There is a rhythm in everything, but the rhythms of
the art of war are especially difficult to master
without practice…. In battle, the
way to win is to know the opponent’s rhythms while
using unexpected rhythms yourself, producing
formless rhythms from the rhythms of wisdom.261
The second ominous scenario that confronts the Joint Force
is the failure to recognize and fully confront the irregular fight
that we are in. The requirement to prepare to meet a wide
range of threats is going to prove particularly difficult for
American forces in the period between now and the 2030s.
The difficulties involved in training to meet regular and
14
nuclear threats must not push preparations to fight irregular
war into the background, as occurred in the decades after
the Vietnam War. Above all, Americans must not allow
themselves to be deluded into believing their future
opponents will prove as inept and incompetent as Saddam
Hussein‘s regime was in 1991 and again in 2003. Having
seen the capabilities of U.S. forces in both regular and
irregular war, future opponents will understand ―the American
way of war‖ in a particularly detailed and thorough way.
In Iraq and Afghanistan our opponents have displayed
considerable capacity to learn and adapt in both the political
and tactical arenas. More sophisticated opponents of U.S.
military forces will certainly attack American vulnerabilities.
For instance, it is entirely possible that attacks on computers,
space, and communications systems will severely degrade
command and control of U.S. forces. Thus, those forces
must possess the ability to operate effectively in degraded
conditions.
In planning for future conflicts, joint force commanders and
their planners must factor two important constraints into their
calculations: logistics and access. The majority of America‘s
military forces will find themselves largely based in North
America. Thus, the first set of problems involved in the
commitment of U.S. forces will be logistical. In the 1980s
many defense pundits criticized the American military for its
supposed over-emphasis on logistics, and praised the
German Wehrmacht for its minimal ―tooth to tail‖ ratio in the
Second World War. What they missed was that the United
States had to project its military forces across two great
oceans, then fight massive battles of attrition in Europe and
in East Asia. Ultimately, the logistical prowess of U.S. and
Allied forces, translated into effective combat forces,
defeated the Wehrmacht on the Western Front, crushed the
15
Luftwaffe in the skies over Germany, and broke Imperial
Japan‘s power.
The tyranny of distance will always influence the conduct of
America‘s wars, and joint forces will confront the problems
associated with moving forces over great distances and then
supplying them with fuel, munitions, repair parts, and
sustenance. In this regard, a measure of excess is always
necessary, compared to ―just in time‖ delivery. Failure to
keep joint forces who are engaged in combat supplied could
lead to disaster, not just unstocked shelves. Understanding
that requirement represents only the first step in planning,
but it may well prove the most important.
The crucial enabler for America‘s ability to project its military
power for the past six decades has been its almost complete
control over the global commons. From the American
standpoint, the Battle of the Atlantic that saw the defeat of
the German U-boat menace in May 1943 was the most
important victory of the Second World War. Any projection of
military power in the future will require a similar enabling
effort, and must recognize that the global commons have
now expanded to include the domains of cyber and space.
The Joint Force must have redundancy built in to each of
these areas to ensure that access and logistics support are
more than ―single-point safe‖ and cannot be disrupted
through a single enemy point of attack.
In America‘s two recent wars against Iraq, the enemy made
no effort to deny U.S. forces entry into the theater. Future
opponents, however, may not prove so accommodating.
Hence, the second constraint confronting planners is that the
United States may not have uncontested access to bases in
the immediate area
16
from which it can project military power. Even in the best
case, allies will be essential to providing the base structure
required for arriving U.S. forces. But there may be other
cases where uncontested access to bases is not available for
the projection of military forces. This may be because the
neighborhood is hostile, or because smaller friendly states
have been intimidated. Hence, the ability to seize bases by
force from the sea and air could prove the critical opening
move of a campaign.
Given the proliferation of sophisticated weapons in the
world‘s arms markets - potential enemies - even relatively
small powers will be able to possess and deploy an array of
longer-range and more precise weapons. Such capabilities in
the hands of America‘s enemies will obviously threaten the
projection of forces into a theater as well as attack the
logistical flow on which U.S. forces will depend. Thus, the
projection of military power could become hostage to the
ability to counter long-range systems even as U.S. forces
begin to move into a theater of operations and against an
opponent. The battle for access may prove not only the most
important, but the most difficult.
One of the major factors in America‘s success in deterring
potential aggressors and projecting its military power over
the past half century has been the presence of its naval
forces off the coasts of far-off lands. Moreover, those forces
have also proven of enormous value in relief missions when
natural disasters have struck. They will continue to be a
significant factor in the future. Yet, there is also the rising
danger with the increase in precision and longer range
missiles that presence forces could be the first target of an
enemy‘s action in their exposed positions.
17
1.5.5 The Conduct of Military Operations in the Twenty-First
Century
The forms of future war will each present peculiar and
intractable challenges to joint forces. The U.S. will always
seek to fight and operate with partners, leading where
appropriate, and prepared to act alone when required to
support our vital national interests. However, there is every
likelihood that there will be few lines of delineation between
one form of conflict and another. Even in a regular war,
potential opponents, engaged in a life and death struggle with
the United States, may engage U.S. forces across the
spectrum of conflict. Thus, the Joint Force must expect attacks
on its sustainment, its intelligence, surveillance and
reconnaissance (ISR) capabilities, and its command and
control networks. The Joint Force can expect future opponents
to launch both terrorist and unconventional attacks on the
territory of the continental United States, while U.S. forces
moving through the global commons could find themselves
under persistent and effective attack. In this respect, the
immediate past is not necessarily a guide to the future.
Deterrence of aggression and of certain forms of warfare
will remain an important element of U.S. national security
strategy, and the fundamentals of deterrence theory will apply
in the future as they have for thousands of years of human
history. Deterrence operations will be profoundly affected by
three aspects of the future joint operating environment.
First, U.S. deterrence strategy and operations will need to
be tailored to address multiple potential adversaries. A ―one-
size-fits-all‖ deterrence strategy will not suffice in the future
joint operating environment. Deterrence campaigns that are
tailored to specific threats ensure that the unique decision
calculus of individual adversaries is influenced.
18
Second, the increased role of transnational non-state
actors in the future joint operating environment will mean that
U.S. deterrence operations will have to find innovative new
approaches to ―waging‖ deterrence against such adversaries.
Non-state actors differ from state actors in several key ways
from a deterrence perspective. It is often more difficult to
determine precisely who makes the key decisions one seeks
to influence through deterrence operations. Non -state actors
also tend to have different value structures and vulnerabilities.
They often possess few critical physical assets to hold at risk,
and are sometimes motivated by ideologies or theologies that
make deterrence more difficult (though usually not
impossible). Non-state actors are often dependent on the
active and tacit support of state actors to support their
operations. Finally, our future deterrence operations against
non-state actors will likely suffer from a lack of well
established means of communications that usually mark state-
to-state relations.
Third, continued proliferation of weapons of mass
destruction will make the U.S. increasingly the subject of the
deterrence operations of others. As such, the U.S. may find
itself in situations where its freedom of action is constrained
unless it can checkmate the enemy‘s deterrent logic.
U.S. nuclear forces will continue to play a critical role in
deterring, and possibly countering, threats to our vital interests
in the future joint operating environment. Additionally, U.S.
security interests will be advanced to the degree that its
nuclear forces are seen as supporting global order and
security. To this end, the U.S. must remain committed to its
moral obligations and the rule of law among nations. It must
provide an example of a responsible and ethical nuclear
power in a world where nuclear technology is available to a
wide array of actors. Only then will the existence of powerful
19
U.S. nuclear forces, in support of the global order, provide
friends and allies with the confidence that they need not
pursue their own nuclear capabilities in the face of growing
proliferation challenges around the world.
Unfortunately, we must also think the unthinkable –
attacks on U.S. vital interests by implacable adversaries who
refuse to be deterred could involve the use of nuclear
weapons or other WMD. For both deterrence and defense
purposes our future forces must be sufficiently diverse and
operationally flexible to provide a wide range of options to
respond. Our joint forces must also have the recognized
capability to survive and fight in a WMD, including nuclear,
environment. This capability is essential to both deterrence
and effective combat operations in the future joint operating
environment.
If there is reason for the joint force commander to
consider the potential use of nuclear weapons by adversaries
against U.S. forces, there is also the possibility that sometime
in the future two other warring states might use nuclear
weapons against each other. In the recent past, India and
Pakistan have come close to armed conflict beyond the
perennial skirmishing that occurs along their Kashmir frontier.
Given India‘s immense conventional superiority, there is
considerable reason to believe such a conflict could lead to
nuclear exchanges. As would be true of any use of nuclear
weapons, the result would be massive carnage, uncontrolled
refugee flows, and social collapse all in all, a horrific human
catastrophe. Given 24/7 news coverage, the introduction of
U.S. and other international forces to mitigate the suffering
would seem to be almost inevitable.
Nuclear and major regular war may represent the most
important conflicts the Joint Force could confront, but they
remain the least likely. Irregular wars are more likely, and
20
winning such conflicts will prove just as important to the
protection of America‘s vital interests and the maintenance of
global stability.
A significant component of the future operating
environment will be the presence of major actors which are
not states. A number of transnational networked organizations
have already emerged as threats to order across the globe.
These parasitic networks exist because communications
networks around the world enable such groups to recruit, train,
organize, and connect. A common desire to transcend the
local regional, and international order or challenge the
traditional power of states characterizes their culture and
politics. As such, established laws and conventions provide no
barrier to their actions and activities. These organizations are
also becoming increasingly sophisticated, well-connected, and
well-armed. As they better integrate global media
sophistication, lethal weaponry, potentially greater cultural
awareness and intelligence, they will pose a considerably
greater threat than at present. Moreover, unburdened by
bureaucratic processes, transnational groups are already
showing themselves to be highly adaptive and agile.
Irregular adversaries will use the developed world‘s
conventions and moral inhibitions against them. On one hand
the Joint Force is obligated to respect and adhere to
internationally accepted ―laws of war‖ and legally binding
treaties to which the United States is a signatory. On the other
hand, America‘s enemies, particularly the non-state actors, will
not find themselves so constrained. In fact, they will likely use
law and conventions against the U.S. and its partners.
21
PERTEMUAN 2
Naval Ship Design
2.1 Pendahuluan
Pokok bahasan materi dalam pertemuan 2 terdiri dari:
a. History of Structural Design-Comercial VS Naval
b. Recent Trends In Naval Vessel Design
c. Naval Structural Design Philosopy
d. Structural Design for Environmental and Operational Loads
e. Structural Design for Military Loads
2.2 Tujuan Instruksional Umum
Setelah mempelajari pokok bahasan materi 2, mahasiswa mampu
memahami History of Structural Design-Comercial VS Naval, Recent
Trends In Naval Vessel Design, Naval Structural Design Philosopy,
Structural Design for Environmental and Operational Loads, Structural
Design for Military Loads
2.3 Tujuan Instruksional Khusus
Setelah mempelajari pokok bahasan materi 2, mahasiswa mampu
menjelaskan History of Structural Design-Comercial VS Naval, Recent
Trends In Naval Vessel Design, Naval Structural Design Philosopy,
Structural Design for Environmental and Operational Loads, Structural
Design for Military Loads
2.4 Skenario Pembelajaran
a. Dosen menjelaskan silabus kuliah, aturan kuliah, dan sistem
penilaian
b. Dosen menjelaskan materi kuliah
c. Diskusi dan tanya jawab dengan mahasiswa
d. Pembagian kelompok
e. Evaluasi pencapaian belajar
22
2.5 Ringkasan Materi:
2.5.1 History of Structural Design-Comercial VS Naval
The structural design of warships has diverged from and
converged with commercial ships throughout history. The Greek
and Roman ramming ships (triremes and biremes) were built
light but with a heavily reinforced keel, compared with the
heavier but more uniform amphora ships of the era. In the
Middle Ages few nations had standing navies and most warfare
was conducted from merchant ships adapted to carry light
guns. In the 1500s the advent of heavy guns and gunports led
to the creation of fleets of specialized ships-of-the-line, having
reinforced decks and hulls to absorb the weight and recoil of the
guns and resist the impact of shot. Even so, warships were
often constructed in the same shipyards as commercial ships;
both designers and workers had little or no difficulty in switching
between the two and in fact often shared technological
advances between the naval and commercial ships. For
example, during the late 1700s many of the European East
Indies fleets built their armed commercial ships using naval
practices; and in the early 1800s, hull strength improvements
pioneered by the British East Indies Company were improved
upon and incorporated into British warships (later, by other
navies as well).
The growing use of iron in shipbuilding from 1820-1860 caused
both navies and commercial ship-owners to rethink design and
build practices. Once again, there was considerable sharing of
new ideas and technologies between the two sectors. Most of
this advance occurred in Britain, the centre of the Industrial
Revolution, where civil engineers working on railways and
bridges were bringing their hard-won knowledge of structural
design practices into the shipbuilding arena; in particular, the
box-girder system developed for the Britannia Bridge became
the paradigm for longitudinal iron framing in ships. In fact, with
23
most navies at this time (soon after the Napoleonic Wars)
operating under austere budgets, much of the fundamental
research into metallurgy and the design of joints was carried out
for the commercial sector, which was undergoing a rapid
expansion due to the increasingly-reliable marine steam engine.
At this time, commercial classification societies.
Beginning in the 1870s, the British navy led the way in
developing structural design practices using calculations based
on fundamental engineering principles. For example, warship
designers began calculating bending moments based on the
static balance of a ship on a wave and a careful enumeration of
the weight distribution along its length. By contrast, most
classification societies at the time settled on semi-empirical
formula that related bending moments to the length and
displacement of the ship. This rule was quite adequate for the
large number of relatively similar merchant ships that were
constructed under classification Rules. Navies, however,
developed and built relatively small numbers of ships, and the
requirements for each one tended to evolve faster than for
merchant ships; so naval constructors tended to revert to basic
engineering principles and lessons learned in their designs.
More importantly, the ability of naval constructors to develop
scantlings was directly related to the rapid progress of naval
architecture education that was specifically directed to serving
navy needs. Put simply, by the early 1900s many navies around
the world had funded schools of naval architecture, whose
graduates overwhelmingly went back to work for the ―sponsor‖.
Most naval design bureaus possessed both the ability and
managerial support to carry out complex calculations. By
contrast, the number of graduate engineers in commercial
shipyard design offices (versus designers coming up from the
shop floor) was still limited.
24
This situation slowly changed during and after World War II for
two related reasons. First, the number of graduate engineers
increased dramatically as companies and governments
recognized the need for higher levels of knowledge and skill in
the new economy, insisting on university degrees for their
engineering workforce. Second, investment in science and
technology also grew sharply, much of it directed to universities
and research centres to advance the state of the art and to
solve practical problems. An early example of this was the
formulation in 1946 of the Ship Structure Committee (SSC) as
an outgrowth of a US Navy Board of Investigation to determine
the causes of the brittle fracture of welded merchant ships
during the war. Similar investigations were conducted by the
Admiralty Ship Welding Committee (later the Advisory
Committee on Structural Steel) in the UK. It is interesting to
note that both of these government committees included their
respective national classification societies as integral members
– recognizing that technology transfer between commercial and
naval practices could be of benefit. The research sponsored by
these organizations included several full-scale tests that greatly
advanced the development of fundamental engineering
requirements for structural rules and ship specifications, while
the new breed of university-trained engineers now possessed
the requisite knowledge to apply advanced technologies. Over
time, the development of improved methods of calculation such
as probabilistic analysis, and the use of computer-aided design
tools such as finite-element codes, were promoted by
classification societies using state-of-the-art engineering
techniques. The ability to perform detailed structural analyses
with high degrees of confidence has aided the rapid growth in
specialized vessels such as LNG carriers, FPSOs and ultra-
large container ships.
25
Although the computational design and analysis processes and
supporting tools applied to naval and commercial vessels were
converging, there were still elements of significance which
made them unique from one another. Navies continued to
develop and refine their own design standards based on
―lessons learned‖ fro m battle damage experience and
extensive research into structural response. From the mid-
1940s to the 1960s, many navies carried out numerous full-
scale trials using decommissioned or captured warships to
examine everything from hull girder bending to the response of
foundations under shock loading. From the 1980s to the 1990s,
full-scale trials were largely replaced by scale model tests and
increasingly sophisticated computer-aided analysis programs,
in many cases based on the same principles as commercial
software codes. The results of these tests and trials have led to
the development of specialized steels for naval ships, and
comprehensive standards and specifications for construction
details to improve damage resistance. For example, most
navies specified the use of symmetrical ―T‖ stiffeners and
continuous welding of members to inhibit structural failure after
shock loading.
Differences such as operations and maintenance also
contributed to the divergence of naval and commercial ship
design standards and methods. Most cargo-carrying ships had
a great variation in loading conditions (fully laden or in ballast),
resulting in greater fatigue cycles than found on naval vessels,
resulting in heavier scantlings for comparable sizes. For
another example, navy crews continuously inspected and
painted hull structures, whereas for commercial ships these
activities were carried out only periodically, e.g., during
drydockings; so in most class Rules, a corrosion (wastage)
26
allowance was specifically called out, which was generally not
present in naval ship design criteria.
Perhaps the most important reason for the continued difference
in naval and commercial design methods was the relative
―democracy‖ of the classification society Rules process,
compared with the ―single party rule‖ generally pre sent in naval
design bureaus. Simply put, classification societies had to (and
still must) adjudicate changes to Rules among numerous
stakeholders, including owners, operators, shipyards and
government regulators. This does not mean so much a ―drive
for the minimum acceptable‖ as much as a balance of many,
often strongly-held, views on the relative importance of cost,
risk, efficiency and safety. By contrast, naval design bureaus
have been fairly small, and though they too must be
accountable to numerous stakeholders as well, in actual fact
the changes to structural design methods and standards were
made and approved by a small cadre of highly experienced
technical staff.
This is now changing. In the post-Cold War era starting in the
1990s and evolving to the present day, many navies have
experienced sweeping cuts in their technical staffs, as
governments changed the way they acquired warships. In the
past these navies had designed their own warships, to their
own specifications. Now, the ship design and construction
process is handled by commercial organizations with the navies
providing only performance criteria to be met and technical
guidance as necessary. In short, many navies can no longer
develop and maintain their own standards and specifications.
Starting with the British navy, but rapidly expanding to others,
the responsibility for these standards have been transferred to
commercial classification societies, under close naval oversight.
27
Although this process is still evolving, early experience has
indicated that many commercial-like ship design processes with
modified naval structural standards are, in fact, quite
comparable to traditional military standards, and in some cases
such as high-speed vessels, certain military-like standards are
needed for the ever-more stringent requirements of commercial
fast ferries. It is likely that naval and commercial vessel Rules
will continue to evolve in parallel and may show some overlaps,
given the current concern by commercial ship owners to
consider survivability against terrorist-like threats. The fact that
classification societies commonly use the same fundamental-
engineering principles as do navies means that naval and
commercial structural design can be developed side-by-side
using comparable means of analysis, so that differences
between them can be properly attributed to required use, and
not to any misunderstanding of methodology.
2.5.2 Recent Trends in Naval Vessel Design
Some of the current trends that will affect the way naval vessels
are designed and built are:
• Modularity, flexibility and multiple missions: The rapid
development of open software standards, ―plug-and-play‖
systems and lea ps in autonomous, remotely-operated
vehicles means that future naval vessels may be configured
to carry out a variety of missions that span the traditional
roles of force projection, combatant and support, either
simultaneously or in sequence; thus, conventional ―rules‖ will
have to be re-examined (for example, will flexible-mission
ships need to be shock-hardened for mine warfare, if the
actual operations are carried out by remote unmanned
vehicles?).
• Enhanced Stealth: In the post-Cold War era, warships will
likely operate far more in littoral regions rather than in open
28
ocean. Signature management (stealth) is increasingly seen
as important to reducing vulnerability to detection and attack
in such environments. Novel structural arrangements,
features and materials are being developed to reduce radar
cross-section, acoustic and thermal emissions, and even
visual signatures.
• Changing Threats: Since the end of the Cold War the nature
of the threats faced by naval vessels has radically changed.
Although prudent designers will always consider ―blue water‖
threats such as submarine lau nched torpedoes and nuclear
attack, it is far more likely that the ships of the near future will
face low tech weapons such as simple mines, easily
available missiles and high-speed boat attacks. Operations in
the littoral will make platforms more vulnerable to low tech
attack and allowances must be made for survivability in these
areas.
• High speed: The age of 40-knot warships was thought to
have ended in World War II, but the emphasis on littoral
operations have revived interest in the tactical advantages of
high speed. Extensive research is needed in the areas of hull
slamming response, fatigue strength and vibrations in thin
structures, in order to develop means to reduce maintenance
and increase hull life.
• Multihull/ advanced hulls: Although novel hull types such as
catamarans, SWATHs, trimarans, hydrofoils, surface-effect
ships, etc. have been in existence for a long time,
requirements for increased speed as described above,
improved
29
• Materials: Shipyards and owners (including navies) continue
to search for newer materials and material systems that will
improve performance and / or reduce construction and
through-life costs. Composite materials and systems (e.g.,
metal-and-plastic sandwiches), novel metals such as
titanium, and coating systems all are being considered to
provide such attributes as lighter weight, ease of fabrication
and higher resistance to corrosion. Another factor is the
increased awareness of terrorist threats that may drive both
naval and commercial vessel owners to consider additional
hardening measures.
• Naval construction by non-indigenous shipyards: During
most of the 20th century, developed nations built their own
naval ships in their own shipyards. In recent years, some of
those nations have begun to contract with foreign (i.e., non-
indigenous) yards to build their naval vessels, and the trend
appears to be on the rise. In some cases, this is due to lower
costs at the foreign yards; in other cases, the sophisticated
integration capabilities required simply do not exist locally.
The implication for structural engineering is a move away
from naval standards to commercial standards, which are
well understood by the foreign yards.
2.5.3 Naval Structural Design Philosophy
Naval ships have traditionally been designed to in-house
standards. A vision was developed for a system of naval ship
regulation based on classification and combining the
strengths of the naval and the commercial regulatory regimes
to provide through life care of naval ships. This chapter gives
a brief survey of known traditional approaches used by
different navies and a brief survey of various approaches by
different classification societies that have published rules for
naval ships.
30
Recognizing that there is no body equivalent to IMO
for naval ships, a NATO Specialist Team on ―Naval Ship
Safety and Classification‖ has been established to develop a
―Naval Ship Code‖. The Code aims to fill the void by
providing the framework for navies to gain assurance that
acceptable levels of safety are achieved. In doing so, the
Code will replicate the link between IMO and Classification
Societies and promote improved ship design and a greater
consistency and transparency of safety standards
Structural Design for Environmental and Operational
Loads
Design Enviromental Loads
As defined by Lloyd‘s Register‘s Rules and Regulati ons
for the Classification of Naval Ships, environmental
conditions include natural phenomena such as wind,
wave and currents and also ice and thermal conditions.
Wave Induced Loads
Global design loads can be divided as follows:
• Hull girder loads are common to both commercial and
military vessels. These include still water shear forces
and associated bending moments, low frequency
vertical wave shear forces and associated bending
moments deriving from hydrodynamic pressures, high
frequency shear forces and associated bending
moments, consequence of slamming phenomena;
• Extreme hull girder loads are those used to assess
ultimate strength and must be derived after an overall
examination of the matrix of all loads which can be
expected;
• Hull girder loads for residual strength assessment are
usually defined to be a specific set of conditions for a
specified period of time. Additional considerations for
31
residual strength assessment are covered in more
depth in Chapter 6.
Still water maximum global loads are to be evaluated
taking account of the worst loading conditions, which are
defined by the Rules and/or the Owners and may vary as
a function of the ship type. It should be noted that the still
water bending moment for a naval ship is, as a rule, less
than that of a commercial vessel.
Like for merchant ships, wave induced loads are defined
by means of physical principles rather than empirical
formulations. As suggested by Boccalatte et al. (2003),
the influence of the main parameters, which govern the
ship response at sea, is to be taken into account.
Starting from IACS procedure, in line with STANAG
4154, this leads to the definition of coefficients, which
consider the peculiar slim hull shapes of combatant
ships, their generally non-vertical sides and their speed.
The formulations proposed by the Classification
Societies, starting from the merchant ship rules, hence
include correction factors that may be also derived by
direct calculation methods up to non-linear ship motion
analyses.
Like high speed craft or some merchant vessel types (i.e.
container or cruise ships), bow flare impacts can give
rise to additional bending moments, which can
significantly increase the design sagging. The evaluation
of such pressures can be carried out as mentioned.
The calculation of ship motions is fundamental for a
correct definition of the dynamic loads acting on the
vessel. Not only such an evaluation allows obtaining the
dynamic portion of local pressures, but also the
32
components of acceleration in the three directions, both
those acting in way of ship centre of gravity and their
distribution along the vessel. A reliable definition of these
accelerations is essential in order to correctly evaluate
the structural behaviour of important components, like for
instance combat systems equipment foundations, and
the dynamic factors that increase loads like those
deriving from parking of aircraft.
Slam induced whipping loads
Whipping is a transient hull response resulting from bow
flare or bottom slamming, which generally induces low
frequency (mainly first mode natural hull frequency) hull
girder bending moments. The effect of whipping loads on
fatigue damage may be significant for more slender and
higher speed vessels (Hansen et al., 1995). Longitudinal
stresses may be significantly affected by slamming
impacts, especially in small and medium size ships.
Generally high wave-induced stresses and high whipping
stresses appear to occur at the same time, but there
tends to be a phase between the whipping initiation and
the peak of hogging ranging from -20 to 70 degrees
(Jiao, 1996). The occurrence of slamming is predicted in
the analytical approach based on the relative velocity
against waves (Hansen et al., 1995).
2.5.4 External Blast Events
As previously stated these result from proximity/stand-off
blasts from, Far field nuclear warheads; stand-off,
proximity or contact bursts from conventional high
explosive (HE) warheads; enhanced blast warheads e.g.
fuel air explosions (FAE), asymmetric/terrorist activity
and discharge of one's own weapons: muzzle blast and
missile motor efflux.
33
Design Requirements
In principle all air blast effects follow the same scaling
law (R/We1/3) independent of the kind of explosion,
nuclear (Glasstone 1957) or non-nuclear (Baker 1983).
The significant differences originate from the
relationships between the characteristic length of the
blast wave and the characteristic lengths of the loaded
structure. The absolute length of a nuclear blast wave is
about 100 times bigger than that of a conventional one.
Thus the characteristic length of a nuclear pulse is in the
order of the ship's length and therefore the loading
mainly causes global effects, while the characteristic
length of conventional explosions is in the order of frame
spacing or deck height respectively, therefore the loading
mainly causes local effects only. The blast-influenced
area is comparable to that characteristic wavelength.
The time of action of the blast wave is also related to the
wavelength. Therefore the response of the structure is
strongly influenced by the response times (natural
frequencies) of the system. Consideration of these
relationships establishes whether impulse effects or
quasi-static behaviour will prevail in the response, thus
determining the most adequate methods of analysis to
be adopted during design.
All components of the ship's structure which affect the
operational and survival capability of the ship should be
designed to meet a set of pre-determined criteria. These
criteria are normally determined by the role of the vessel
34
and set out in the operational requirements. This may be
accomplished by calculation (Biggs 1964) as discussed
in the previous paragraph and/or by use of pertinent data
from large-scale blast experiments
In view of the time dependence of the impulsive loadings
involved in Air Blast, the use of static analysis to
compute the structural response to air blast loadings has
severe limitations, however if coupled with a suitable
dynamic loading factor they can be used to provide a first
approximation for design purposes Forrestal et al. 1977).
35
PERTEMUAN 3
Military and Commercial Shipbuilding
3.1 Pendahuluan
Pokok bahasan materi dalam pertemuan 3 terdiri dari:
a. Military and Commercial Shipbuilding Trends
b. How Military and Commercial Shipbuilding Differ
c. The Potential for Ferign Military Sales
d. Integration Versus Specialisation at the Shipyard Level
3.2 Tujuan Instruksional Umum
Setelah mempelajari pokok bahasan materi 3, mahasiswa mampu
memahami Military and Commercial Shipbuilding Trends, How Military
and Commercial Shipbuilding Differ, The Potential for Ferign Military
Sales, Integration Versus Specialisation at the Shipyard Level
3.3 Tujuan Instruksional Khusus
Setelah mempelajari pokok bahasan materi 3, mahasiswa mampu
menjelaskan Military and Commercial Shipbuilding Trends, How
Military and Commercial Shipbuilding Differ, The Potential for Ferign
Military Sales, Integration Versus Specialisation at the Shipyard Level
3.4 Skenario Pembelajaran
a. Dosen menjelaskan silabus kuliah, aturan kuliah, dan sistem
b. penilaian
c. Dosen menjelaskan materi kuliah
d. Diskusi dan tanya jawab dengan mahasiswa
e. Pembagian kelompok
f. Evaluasi pencapaian belajar
3.5. Ringkasan Materi:
3.5.1 Shipbuilding Trends
The demand for commercial shipbuilding in the global
marketplace has increased from a lull in the late 1980s to a
peak in 2002 and 2003. Some national shipbuilding industries,
notably the German and the Dutch, recovered during this
36
period. The French shipbuild-ing industry took somewhat longer
but eventually recovered. The US commercial shipbuilding
industry, largely a protected one and un-competitive in the
global market, also recovered slowly from a similar downturn in
its domestic demand. The United Kingdom‘s commer-cial
industry began to recover in the early 1990s before fading again
in the middle part of the decade. As of early 2003, there was
only one sizable commercial ship under construction in a UK
shipyard (the HMS Anvil Point, a roll-on/roll-off cargo ship).
The United Kingdom has, however, sustained a military ship-
building industrial base of substantial size throughout the last
quarter-century. The value of its future domestic demand is
expected to be on the order of that of France and Japan and
much larger than Germany‘s. However, UK shipbuilders are
expected to export very few military ships compared with
projects of the Germans and French.
3.5.2 Differences Between Military and Commercial Shipbuilding
If the UK commercial market is to expand, military shipbuilders
will presumably have to begin building commercial ships,
because the commercial industrial base is so small. The
construction of all but the most complex commercial ships,
however, differs dramatically from that of warships along
several dimensions:
• Ship size and complexity. The average commercial ship is
about three times as big as the average military ship and thus
cannot be built in facilities sized for military ships. At the same
time, the average commercial ship is much simpler (e.g., no
weapon sys-tem) than the average military ship.
• Acquisition process. Commercial ship owners are
accustomed to much simpler contracting, designing,
construction, and testing processes than those that pertain in
the military world.
37
• Design and construction. Commercial ships are, for the
most part, large steel boxes with relatively small and simple
propul-sion and navigation systems. Designing military ships
takes longer because of their high equipment density, the large
num-ber of sophisticated systems involved, and a desire to at
least match the current state of the art. Construction of
commercial ships is mostly a volume business that depends on
simple steel forming and welding processes repeated over and
over. The con-struction of warships involves the use of exotic
materials, the installation of large amounts of high-value,
sensitive equipment, and the satisfaction of more exacting
standards. The testing process for military ships is more
involved because it has to reflect the high technology and
technology density of the ships and take account of multiple
possibilities for mutual interference of advanced electronic
systems.
• Workforce character. In the United Kingdom, military ship-
building requires a much higher ratio of white- to blue-collar
workers than that found in commercial shipbuilding. This is
because military shipbuilding demands much more engineering
support, as well as the need to interact extensively with the gov-
ernment oversight team. Military shipbuilding also requires
more highly skilled and specialised workers. Such high
overhead and high skill base cannot be sustained by any yard
that expects to build typical commercial ships at competitive
prices.
3.5.3 Prospects for Market Entry an Integration
As suggested above, the United Kingdom would face strong
competi-tors in attempting to re-enter the commercial
shipbuilding market. Japan and South Korea dominate the
market for ships of low and moderate complexity, mostly cargo
ships and tankers of varying types. The European Union
dominates the market for more-complex ships such as
38
passenger vessels, although that market segment is also under
pressure from Asian shipbuilders. The global shipbuilding
market has for some years been characterised by excess
capacity, so profits have been low. A newcomer would face
formidable impediments to securing a meaningful market niche
in such an environment. Towards the latter half of 2003,
demands for certain ship types (mostly very large container
ships, bulk carriers, and liquefied natural gas [LNG] tankers)
suddenly soared, pressing the available builders and, we
surmise, increasing profits. The United Kingdom has not been
in a position to take advantage of this shift and cannot count on
it lasting for long. UK shipyards attempting to enter or re-enter
the commercial shipbuilding market would also have to find a
way to resolve all the workforce, process, and facility issues
discussed above in a niche that took advantage of their special
high-skill and high-complexity capabilities. Finally, the pound
has recently been strong against the dollar, which also works
against the United Kingdom‘s export interests. We thus find
prospects for re-entry of UK shipyards into the commercial
market to be, on the whole, daunting.
The military export market is small in value compared with the
commercial market. It nonetheless represents a tempting target
for a nation with a largely military industry that is attempting to
gain some ability to level the load over domestic military
production lulls. Here again, UK shipbuilders face strong
competitors in Germany and France, which together have more
than 60 percent of the military export market. The United
Kingdom certainly has a stronger indus-trial base to support
military sales than it does in the commercial arena, but the
match between most current UK military ship prod-ucts and
global demand is not a close one. The military export mar-ket is
largely a market for modestly priced frigates and small conven-
tionally powered attack submarines. It is not clear that a UK
39
shipyard could build a conventional submarine at a competitive
price; UK warships are, in general, too sophisticated and
expensive to make them interesting to potential importers.
Furthermore, export con-tracts often require that most ships in
an order be built in the importing country, thus limiting the
benefit such sales may have for the exporter‘s construction
workforce.
As mentioned above, should the United Kingdom attempt to re-
enter the commercial market, shipyards currently building
military ships would have to diversify into commercial
production. While some yards do have experience with naval
auxiliaries or recent com-mercial projects, the historical trend
has been more towards speciali-sation than integration of
commercial and military production. Inte-gration can, of course,
bring the benefits of military technological advances to
commercial construction, and the benefits of efficient
commercial processes can feed back to the military side.
However, most successful shipbuilders have found it difficult to
build both mili-tary and commercial ships, of any degree of
complexity, within the same operation. Certain Japanese yards
constitute a possible excep-tion, and their practices warrant
further investigation.
3.5.4 The Way Forward
While prospects for broadening UK shipyards‘ customer base
would appear to be poor, the shipbuilding industry is a volatile
one, and events could always break unexpectedly in the United
Kingdom‘s favour. Taking advantage of such opportunities
requires some prepa-ration, such as the development of less
expensive warship designs that reflect the needs of potential
buyers. Research and development directed towards a
generation-skipping commercial design or dra matic
technological advances in systems and materials could also be
fruitful.
40
Of course, development of new designs and technologies would
require investment on the part of shipbuilders and marine
equipment suppliers and potentially on the part of government,
if appropriate and if consistent with EU rules. It would require
investment, for example, in sustaining core design and
programme management skills through lulls in orders. These
investments would be risky, because the probabilities of payoff
would not be high, but externalities might accrue to domestic
military shipbuilding and to other UK industries.
This work could not have been undertaken without the
steadfast support and encouragement we received from Sir
Robert Walmsley, then Chief of Defence Procurement and
Chief Executive, DPA, and members of his staff. Many
individuals in the MOD provided their time, knowledge, and
information to help us perform the analyses discussed in this
report. Their names and contributions would fill several pages.
If we were to single out two persons who participated in and
supported this work in extraordinary ways, we would mention
our action officer Andy McClelland of the DPA and Robin
Boulby of the Future Aircraft Carrier programme‘s Integrated
Project Team. Their tireless efforts on our behalf are greatly
appreciated, along with their constructive comments on earlier
drafts.
We are also indebted to the UK, US, and EU shipyards that
par-ticipated in this study. Each gave us the opportunity to
discuss a broad range of issues with the people directly
involved. In addition, all the firms arranged for us to visit their
facilities. The firms and gov-ernment offices provided all the
data we requested in a timely man-ner.
We are indebted to Brien Alkire of RAND and Philip Koenig of
the Office of Naval Research for their formal review of the
41
document and the many improvements and suggestions they
made. Professor Thomas Lamb of the University of Michigan
participated in data collection and made several helpful
suggestions for the analysis— we thank him for his time and
help. We are additionally indebted to Joan Myers for her deft
assistance organising and formatting the many drafts.
42
PERTEMUAN 4
Introduction to Aircraft Stability
4.1 Pendahuluan
Pokok bahasan materi dalam pertemuan 4 terdiri dari:
a. Aerodinamic Background
b. Static Longitudinal Stability and Control
c. Dynamical Equations of Motion
d. Dynamic Stability
e. Control of Aircraft Motions
4.2 Tujuan Instruksional Umum
Setelah mempelajari pokok bahasan materi 4, mahasiswa mampu
memahami Aerodinamic Background, Static Longitudinal Stability
and Control, Dynamical Equations of Motion, Dynamic Stability,
Control of Aircraft Motions
4.3 Tujuan Instruksional Khusus
Setelah mempelajari pokok bahasan materi 4, mahasiswa mampu
menjelaskan Aerodinamic Background, Static Longitudinal Stability
and Control, Dynamical Equations of Motion, Dynamic Stability,
Control of Aircraft Motions
4.4 Skenario Pembelajaran
a. Dosen menjelaskan silabus kuliah, aturan kuliah, dan sistem
penilaian
b. Dosen menjelaskan materi kuliah
c. Diskusi dan tanya jawab dengan mahasiswa
d. Pembagian kelompok
e. Evaluasi pencapaian belajar
4.5. Ringkasan Materi:
4.5.1 Aerodynamic Controls
An aircraft typically has three aerodynamic controls, each
capable of producing moments about one of the three basic
axes. The elevator consists of a trailing-edge flap on the
43
horizontal tail (or the ability to change the incidence of the entire
tail). Elevator deflection is characterized by the deflection angle
δe. Elevator deflection is defined as positive when the trailing
edge rotates downward, so, for a configuration in which the tail
is aft of the vehicle center of mass, the control derivative
∂Mcg < 0
∂δe
The rudder consists of a trailing-edge flap on the vertical tail.
Rudder deflection is characterized by the deflection angle δr .
Rudder deflection is defined as positive when the trailing edge
rotates to the left, so the control derivative
∂Ncg < 0
∂δr
The ailerons consist of a pair of trailing-edge flaps, one on each
wing, designed to deflect differentially; i.e., when the left aileron
is rotated up, the right aileron will be rotated down, and vice
versa. Aileron deflection is characterized by the deflection angle
δa. Aileron deflection is defined as positive when the trailing
edge of the aileron on the right wing rotates up (and,
correspondingly, the trailing edge of the aileron on the left wing
rotates down), so the control derivative
∂Lcg > 0
∂δa
By vehicle symmetry, the elevator produces only pitching
moments, but there invariably is some cross-coupling of the
rudder and aileron controls; i.e., rudder deflection usually
produces some rolling moment and aileron deflection usually
produces some yawing moment.
44
4.5.2 Atmospheric Properties
Aerodynamic forces and moments are strongly dependent upon
the ambient density of the air at the altitude of flight. In order to
standardize performance calculations, standard values of
atmospheric properties have been developed, under the
assumptions that the atmosphere is static (i.e., no winds), that
atmospheric properties are a function only of altitude h, that the
temperature is given by a specified piecewise linear function of
altitude, and that the acceleration of gravity is constant
(technically requiring that properties be defined as functions of
geopotential altitude. Tables for the properties of the Standard
Atmosphere, in both SI and British Gravitational units, are given
on the following pages.
4.5.3 Aerodynamic Background
Aerodynamic Properties of Airfoils
For low speeds (i.e., Mach numbers M << 1), and at high
Reynolds numbers Re = V c/ν >> 1, the results of thin-airfoil
theory predict the lifting properties of airfoils quite accurately for
angles of attack not too near the stall. Thin-airfoil theory
predicts a linear relationship between the section lift coefficient
and the angle of attack α of the form
cℓ = a0 (α − α0)
as shown in Fig. 2.3. The theory also predicts the value of the
lift-curve slope
a0 = ∂cℓ = 2π
∂α
Thickness effects (not accounted for in thin-airfoil theory) tend
to increase the value of a0, while viscous effects (also
neglected in the theory) tend to decrease the value of a0. The
value of a0 for realistic conditions is, as a result of these
counter-balancing effects, remarkably close to 2π for most
practical airfoil shapes at the high Reynolds numbers of
practical flight.
45
The angle α0 is called the angle for zero lift , and is a function
only of the shape of the camber line. Increasing (conventional,
sub-sonic) camber makes the angle for zero lift α0 increasingly
negative. For camber lines of a given family (i.e., shape), the
angle for zero lift is very nearly proportional to the magnitude of
camber – i.e., to the maximum deviation of the camber line from
the chord line.
A second important result from thin-airfoil theory concerns the
location of the aerodynamic center . The aerodynamic center of
an airfoil is the point about which the pitching moment, due to
the distribution of aerodynamic forces acting on the airfoil
surface, is independent of the angle of attack. Thin-airfoil theory
tells us that the aerodynamic center is located on the chord line,
one quarter of the way from the leading to the trailing edge –
the so-called quarter-chord point. The value of the pitching
moment about the aerodynamic center can also be determined
from thin-airfoil theory, but requires a detailed calculation for
each specific shape of camber line. Here, we simply note that,
for a given shape of camber line the pitching moment about the
aerodynamic center is proportional to the amplitude of the
camber, and generally is negative for conventional subsonic
(concave down) camber shapes.
It is worth emphasizing that thin-airfoil theory neglects the
effects of viscosity and, therefore, cannot predict the behavior
of airfoil stall, which is due to boundary layer separation at
high angles of attack. Nevertheless, for the angles of attack
usually encountered in controlled flight, it provides a very
useful approximation for the lift.
46
Airfoil section lift coefficient as a function of angle of attack
Airfoil lift and moment coefficients as a function of angle of
attack; wind tunnel data for two cambered airfoil sections
Finally, wind tunnel data for two cambered airfoil sections are
presented in Fig. 2.4. Both airfoils have the same thickness
distributions and camber line shapes, but the airfoil on the
right has twice as much camber as the one on the left
(corresponding to 4 per cent chord, versus 2 per cent for the
airfoil on the left). The several curves correspond to Reynolds
numbers ranging from Re = 3 × 106 to Re = 9 ×106, with the
curves having larger values of cℓmax corresponding to the
higher Reynolds numbers. The outlying curves in the plot on
47
the right correspond to data taken with a 20 per cent chord
split flap deflected (and are not of interest here).
Note that these data are generally consistent with the results
of thin-airfoil theory. In particular:
1. The lift-curve slopes are within about 95 per cent of the
value of a0 = 2π over a significant range of angles of
attack. Note that the angles of attack in Fig. 2.4 are in
degrees, whereas the a0 = 2π is per radian;
2. The angle for zero lift of the section having the larger
camber is approximately twice that of the section having
the smaller camber; and
3. The moment coefficients measured about the quarter-
chord point are very nearly independent of angle of attack,
and are roughly twice as large for the airfoil having the
larger camber.
Aerodynamic properties of finite wings
The vortex structures trailing downstream of a finite wing
produce an induced downwash field near the wing which can
be characterized by an induced angle of attack
For a straight (un-swept) wing with an elliptical spanwise
loading, lifting-line theory predicts that the induced angle of
attack αi is constant across the span of the wing, and the
efficiency factor e = 1.0. For non-elliptical span loadings, e <
1.0, but for most practical wings αi is still nearly constant
across the span. Thus, for a finite wing lifting-line theory
predicts that
48
where a0 is the wing section lift-curve slope and α0 is the angle
for zero lift of the section. Substituting Eq. (2.16) and solving
for the lift coefficient gives
whence the wing lift-curve slope is given by
Lifting-line theory is asymptotically correct in the limit of large
aspect ratio, so, in principle, Eq. (2.18) is valid only in the limit
as AR → ∞. At the same time, slender-body theory is valid in
the limit of vanishingly small aspect ratio, and it predicts,
independently of planform shape, that the lift-curve slope is
a = πAR
2
Note that this is one-half the value predicted by the limit of the
lifting-line result, Eq. (2.19), as the aspect ratio goes to zero.
We can construct a single empirical formula that contains the
correct limits for both large and small aspect ratio of the form
49
PERTEMUAN 5
Konsep Struktur Fighter
5.1 Pendahuluan
Pokok bahasan materi dalam pertemuan 5 terdiri dari:
a. Struktur Analysis
b. Strukrur Design & Payload Design
5.2 Tujuan Instruksional Umum
Setelah mempelajari pokok bahasan materi 5, mahasiswa mampu
memahami Struktur Analysis, Strukrur Design & Payload Design
5.3 Tujuan Instruksional Khusus
Setelah mempelajari pokok bahasan materi 5, mahasiswa mampu
menjelaskan Struktur Analysis dan Strukrur Design & Payload
Design
5.4 Skenario Pembelajaran
a. Dosen menjelaskan silabus kuliah, aturan kuliah, dan sistem
penilaian
b. Dosen menjelaskan materi kuliah
c. Diskusi dan tanya jawab dengan mahasiswa
d. Pembagian kelompok
e. Evaluasi pencapaian belajar
5.5. Ringkasan Materi:
5.5.1 Struktur Analysis
Bidang Kompetensi
• Stress Analysis
• Aircraft Load Analysis
• Aerolasticity
• Fatique & Fracture Mechanics
• Weight and Balance
50
Stress Analysis
• Finite Element Modeling
• Stress Analysis
• Composite Stress Analysis
• Static Stability Analysis
• Structure Design Optimization
• Static Test Requirement and Result Analysis
• Bird Impact Analysis & Test
• Certification Plan
• Aircraft Crashworthiness
Nastran, Patran and our in house programs are widely used in
Structural Stress Analysis
Aircraft Load Analysis
• Flight Load Analysis
• Ground Load Analysis
• Emergency Load Analysis
• Miscellaneous Load Analysis
• Aircraft Component Load Analysis
• Load Analysis Software Development
• In-flight Load Measurement
• Aircraft Operating Limitation
• Load Analysis Cerftification
51
• Post-TC Maintenance Support
Aeroelastic and Dynamic Analysis
• Structural Dynamic Analysis
• Divergence & Control Reversal Analysis
• Usteady Aerodynamic & Flutter Analysis
• Propeller Aerodynamic Derivative 7 Whirl Flutter Analysis
• Dynamic Gust Analysis
• Landing Impact Analysis
• Shimmy Analysis
• Ground Vibration Test
• Flight Flutter Test
• Aeroelastic Certification
• Post-TC Maintenance Support
52
Fatique and Fracture Mechanics
• Fatique Analysis
• Damage Tolerance Analysis
• Fatique Certification Plan
• Structure Repair Manual
• Aging Aircraft Evaluation
• Load Spectra Development
• In-sevice Fatique Load Measurement
• Fatique & Damage Tolerance Test
• Inspection Program Development
• Principle Structure Elemnt Selection
5.5.2 Structure & Payload Design
Structure Design
• Metallic Part Design
• Composite Part Design
•
• Digital Part List (DPL) Generation
53
Structure and System Integration
• Catia Digital Mock Up Creation
• Interface Design and Lay Out
• Design Installation of Customer Option Components
Sustaining Program Engineering Support
• Existing Aircraft Program Modification
• Manual Drafting and Drawing Updating
• Manual Drawing to CATIA Modeling/Conversion
• CADDS5 Drawing/ Model to CATIA Modeling/ Concersion
Payloads Design
54
Konsep Teknologi Struktur Fighter
• Structure Design Concept
\
55
56
Case Study of The Wing Layout
Case Study of Wing-Fuselage Fitting
57
Trend of the Material Technology
58
59
PERTEMUAN 6
INTRODOUCTION TO FIGHTER
6.1 Pendahuluan
Pokok bahasan materi dalam pertemuan 6 terdiri dari:
a. Kompetensi Dalam Pengembangan Pesawat Terbang
b. Airplane Integration
c. History Of Jet Fighter
6.2 Tujuan Instruksional Umum
Setelah mempelajari pokok bahasan materi 6, mahasiswa mampu
memahami Kompetensi Dalam Pengembangan Pesawat Terbang,
Airplane Integration, History Of Jet Fighter
6.3 Tujuan Instruksional Khusus
Setelah mempelajari pokok bahasan materi 6, mahasiswa mampu
menjelaskan Kompetensi Dalam Pengembangan Pesawat Terbang,
Airplane Integration, History Of Jet Fighter
6.4 Skenario Pembelajaran
a. Dosen menjelaskan silabus kuliah, aturan kuliah, dan sistem
penilaian
b. Dosen menjelaskan materi kuliah
c. Diskusi dan tanya jawab dengan mahasiswa
d. Pembagian kelompok
e. Evaluasi pencapaian belajar
60
6.5. Ringkasan Materi:
6.5.1 Kompetensi Dalam Pengembangan Pesawat Terbang
• Flight Physics: Aerodynamics, A/C Performance, S&C ,
Propulsion Analysis, dst.
• Flight Structure: Weight, Load, Stress Analysis,
Aeroelasticity, Fatigue & damage Tolerance, Payload
Design, Structure Design
• Flight System: Avionik, Flight Control, Propulsion,
Subsystem, System Design & Installation
• System Engineering: Risk Management, RM&S, Test &
Evaluation, Certification Management, System Engineering
• Management
Evolution of an Airplane (The Role of Technology Group)
61
Evolution of an Airplane (The Role of Aircraft Design
Group)
Airplane Program Phasing
62
Aspek-Aspek dalam Perancangan Pesawat Terbang
Different Disciplines Different Dream
6.5.2 Airplane Integration
63
Transport Aircraft Design Objectives and Constraints
Comparison Of Commercial And Military Aircraft Development
History Of Jet Fighter
64
65
66
67
68
PERTEMUAN 7
Propulsion
7.1 Pendahuluan
Pokok bahasan materi dalam pertemuan 7 terdiri dari:
a. Propulsion Analysis
b. Propulsion Integration
7.2 Tujuan Instruksional Umum
Setelah mempelajari pokok bahasan materi 7, mahasiswa mampu
memahami Propulsion Analysis, Propulsion Integration
7.3 Tujuan Instruksional Khusus
Setelah mempelajari pokok bahasan materi 7, mahasiswa mampu
menjelaskan Propulsion Analysis, Propulsion Integration
7.4 Skenario Pembelajaran
a. Dosen menjelaskan silabus kuliah, aturan kuliah, dan sistem
penilaian
b. Dosen menjelaskan materi kuliah
c. Diskusi dan tanya jawab dengan mahasiswa
d. Pembagian kelompok
e. Evaluasi pencapaian belajar
7.5. Ringkasan Materi:
7.5.1 Propulsion analysis
Propulsion Analysis includes air induction system design,
installed engine performance analysis, and aircraft after-body
design
69
Functional Interface
Sizing & Design
70
Inlet Trade Study
7.5.2 Propulsion Integration
Propulsion Integration Overview
71
72
System Requirement Analysis
73
OTS System Review
74
System Development
75
76
77
PERTEMUAN 8
UTS
78
PERTEMUAN 9
Structural, Design and Analysis
9.1 Pendahuluan
Pokok bahasan materi dalam pertemuan 9 terdiri dari:
a. State of the Art
b. The Method
c. Generation of efficient design alternatives
9.2 Tujuan Instruksional Umum
Setelah mempelajari pokok bahasan materi 9, mahasiswa mampu
memahami State of the Art, The Method, Generation of efficient
design alternatives
9.3 Tujuan Instruksional Khusus
Setelah mempelajari pokok bahasan materi 9, mahasiswa mampu
menjelaskan State of the Art, The Method, Generation of efficient
design alternatives
9.4 Skenario Pembelajaran
a. Dosen menjelaskan silabus kuliah, aturan kuliah, dan sistem
penilaian
b. Dosen menjelaskan materi kuliah
c. Diskusi dan tanya jawab dengan mahasiswa
d. Pembagian kelompok
e. Evaluasi pencapaian belajar
9.5. Ringkasan Materi:
9.5.1 State of the Art
Maritime Safety
As indicated by the IMO (2002) and the research
community (Cho et al. 2006, Moore et al. 2009), to
correctly undertake the establishment of maritime safety
79
criteria, it is necessary to consider the maritime
stakeholders and their preferences. Freeman (1984)
describes stakeholders as actors whose interests in a
system need to be addressed, while Roy (1996) notes that
stakeholders demonstrate preferences towards options.
would arrive by a pipeline. The project, after many years of
planning, infamously failed as a result of the intensive
public outcry for the protection of the environment.
Counter-initiatives were strictly conducted in Croatia, and
nothing similar occurred in any other country with a
shoreline touching the Adriatic. On the other hand, no
specific measures were taken by the government or
industrial stakeholders to implement safer operations
beyond the minimum requirements of industry standards
and international conventions. The irony of such an
outcome is in the fact that during the time of the planning
of the project, and still today, a very intensive import traffic
of Arabian oil was conducted at the harbour of Trieste,
Italy, also located in the North Adriatic. And no protests
were heard. We can only wonder whether the outcome
would have been different if the government and industry
had had the capacity and willingness to implement e.g.
ships with improved crashworthiness.
related to a system. In that sense, we can also observe
the maritime stakeholders and their preferences regarding
safety. All maritime stakeholders consider safety
extensively in their activities, but they obviously do not
possess the same preferences concerning it, e.g. how
much is to be invested into averting a life lost or a ton of
oil spilled.
Not everybody benefits from safety equally, and nor does
everybody have a chance to manage safety in the
80
maritime industry. For example, ship owners manage
safety directly through operations, while the yard has the
responsibility to meet the minimum requirements in
designing and building a ‗safe‘ product. The minimum
requirements are elicited, on the other hand, through a
stakeholder dialogue, which includes the industry and the
regulators with the mandate of serving society overall.
Because of their roles in society, the risks and profits they
face differ significantly, and so do their preferences. This
inevitably leads to a different ranking of priorities.
Bennett (2001) and Pöyhönen (2000) describe typical
examples of these preferences. Their findings could be
summed up as follows. The commercial aspects are
primarily considered relevant by the industry, while society
and individual professionals like seamen are more
interested in improving safety but without any great
willingness to bear the economic burden.
A number of studies seek to establish criteria that follow
these findings (Vatn 1998, Melchers 2001, Aven 2003). By
formally establishing the maximum tolerance of risk for the
public, i.e. the minimum safety requirements, and the
maximum for efficient investments into safety, a so-called
‗As Low As Reasonably Possible‘ or ALARP region of
relevant strategies for safety management can be
established; see Figure 2.
The determination of the maximum risk tolerance and of
the maximum for efficient investments differs among the
studies. Ditlevsen (2003) employs profiling of the nature of
maritime risk, i.e. critical intolerance of high-consequence
accidents that possess low occurrence, to establish the
minimum acceptable levels of safety. Skjong and Ronold
(1998), on the other hand, use a Life Quality Index (Lind
81
1996) to establish how much should be maximally
invested into the prevention of the loss of life. A so-called
‗upper bound criterion‘ of Implied Cost of Averted Fatality,
or ICAF threshold, is defined on the premise of the
economic activity of a life lost. Depending on the area of
operations observed, or persons‘ origin, this value ranges
between 300 k€ and about 3 M€. Should the investment
into safety be efficient, the CAF, or the Cost to Avert the
Fatality, defined as the ratio
ALARP – ‗as low as reasonably practical‘ probabilities (Melchers
2001) with typical risk acceptance frequency for the number of
fatalities (Pedersen 2010)
between the costs of investment in reducing the risk of
loss of life and the expected reduction in loss of life, needs
to be smaller than the threshold value of ICAF. Ditlevsen
and Friis-Hansen (2003), combining the works above,
establish a decision criterion for the acceptance of risk by
the public to determine the threshold of the maximum
amount to be invested into the aversion of environmental
82
loss. The criterion is based on the balance between the
benefits of maritime transport to the public and the risks it
brings to the public. Following this work, and the work of
Skjong and Vanem (2005), the IMO (2008) established the
threshold of Cost to Avert a Tonne of Spillage, or
CATSthr, at about 50 k€. CATS2 itself is established
analogously to CAF.
ICAF and CATSthr are very straightforward values for
determining the efficiency of the investments being
considered, but they lack the capacity to distinguish
between low and high risks, as well as between the
particular preferences of maritime stakeholders, which are
relevant from the point of view of this study. They lack the
capacity to determine the optimum amount of investments
into safety, i.e. that the design alternative approaching the
threshold would be considered optimal. Furthermore, the
values of CAF and CATS should not be used as criteria,
i.e. the less the better, as they can produce very
misleading figures, where their minima can be found e.g.
for very ‗cheap‘ alternatives with a minimum of risk
reduction. The opposite, i.e. to maximise CAF and CATS,
is irrational. ICAF and CATSthr are also determined in
general, so they lack the sensitivity to capture the aspects
of a particular ship project. Thus, they can be misleading if
applied alone.
As an alternative, Rosqvist and Tuominen (2004) and
French et al. (2005) consider a multi-attribute decision-
making framework. Assuming full compensation for the
costs and benefits of safety investments amongst the
stakeholders, they establish a more rational framework to
determine the optimal amount of investment. No firm or
predetermined thresholds are implied, as the selection is
83
based strictly on the preferences of stakeholders. On this
basis, and on the IMO‘s (IMO 2002) recommendation for
the fair treatment of stakeholders‘ preferences, Rosqvist
(2003) provides a selection criterion where the optimum of
safety investments is found for the design alternative with
the fairest distribution of the corresponding risks between
the stakeholders.
The validity of the assumption of full compensation
amongst stakeholders is reasonable if one considers a
very broad domain of stakeholders. Enough stakeholders
make up the total economics of maritime transport and are
thus part of the fully compensated system. Such a
situation then easily correlates with safety as defined in
international conventions, industry standards, and
practices, e.g. when considering the updating of statutory
rules. Within a narrower context, e.g. the structural design
of a ship, the validity of the assumption about full
compensation amongst stakeholders comes in question.
The number of stakeholders involved, i.e. those sensitive
to the changes in structural design, is smaller. Obviously,
these represent only a part of the total economics, and the
assumption of full compensation can no longer be
guaranteed. Hence, an alternative approach should be
considered.
Game Theory
Vincent and Grantham (1981) show how a design process
can be described as a decision-making problem.
Designing to satisfy the preferences of multiple
stakeholders can then be seen as a group decision-
making problem, where each stakeholder is treated as a
decision maker.
84
Differing preferences lead to competitive relationships
between stakeholders (Håkansson and Henders 1990). In
such relationships stakeholders are not willing to renounce
any of their benefits as they try to maximise them
independently (Duetsch 1949, Wilkinson and Young
1994). Such a decision-making problem is formalised
effectively through the theory of mathematical games, or
Game Theory (v Neumann and Morgenstern 1944,
Meyerson 1991, Keeney and Raiffa 1977). Two types of
games can be distinguished. A static game describes a
situation in which each stakeholder makes a choice from a
fixed set of strategies, and where this set does not depend
on the choices made by other stakeholders. A dynamic
game, on the other hand, possesses varying sets of
strategies, which depend on the choices made. A dynamic
game obviously assumes that the choices are made at
least twice, and thus it can, in a simplified manner, be
understood as a series of static games.
According to the above definition, ship design is a
dynamic process. Thus, utilising a dynamic game would
be the most appropriate way to map it and thus solve it.
However, ship design is also complex, and the elicitation
of the available strategies and consequences of the
choices made cannot be defined explicitly. Similarly to the
game of chess, it cannot be mapped, but it can be tackled.
Maritime stakeholders, through preferences, trade off
between the costs and benefits they face with a ship either
in production or in operation. In the case of safety, this
refers to the cost-effectiveness of any risk control option
that is considered. Therefore, a single static game can be
derived in such a way that it models the cost-effectiveness
of the alternatives and allows the selection of one option
85
that optimally satisfies all stakeholder preferences, as
shown in Figure 2.
The ‗dynamic‘ part of the design decision making can be
approximated with design optimization; again, see Figure
2. If we are aiming to select the best design alternative,
then the alternatives that are considered should be good
solutions.
Design decision-making process modelled as a) a dynamic and b) a static
mathematical game with the Nash Equilibrium marked.
Speaking in terms of multi-objective optimization, design
alternatives considered for selection through a static game
should be non-dominated solutions of the optimization
problem. The non-dominated solutions, or Pareto optima,
possess attributes that are not entirely outranked
(dominated) by any other alternative under consideration
(Pareto 1896). Extending this to the utilities of
stakeholders, the non-dominated design alternatives
effectively become compromise solutions between
stakeholder preferences. In terms of group decision
making, they are collectively stable solutions (Rao et al.
1997), i.e. their attributes and utilities cannot all be
simultaneously improved by any alterations in order to
reach a new feasible design.
86
Depending on the nature of the game, a static game
possesses several well-known solutions, e.g. Min-Max,
Bayesian, etc. For the competitive games, the classic
solution of Nash (Nash 1951), better known as Nash
Equilibrium, is considered often. It is defined as the
outcome of the optimal choice of strategies of
stakeholders in their response to the optimal choices of
others. Such a solution can be defined as ‗individually
stable‘ (Rao et al. 1997), referring to the fact that no
unilateral decision by any stakeholder will result in higher
benefits for that stakeholder than at the Nash Equilibrium.
In this case, the Nash Equilibrium will yield an alternative
that optimally distributes the benefits and costs related to
the risk reduction amongst the stakeholders. However,
Dubey (1986) shows that the Nash Equilibrium of a static
competitive game will probably be a non-efficient solution.
Saksala (2005) vividly depicted this ‗anomaly3‘ for a
number of cases in structural design. Such an outcome is
then irrational with respect to the considerations of ship
design in general, as another alternative can provide more
benefits to all stakeholders than the Nash Equilibrium.
Special care should thus be taken when considering the
application of Nash Equilibrium.
9.5.2 Scope of the work
Based on the indicated research gap in the four observed
research areas, i.e. maritime safety, Game Theory, ship
structural optimization for multiple objectives, and
collisions and grounding of ships, Figure 4 symbolically
indicates th e scope of this thesis. We can notice that thes
e contributions are principally located at the interfaces of
the four observed research areas, and can be classified
87
into: i) design selection; ii) GA optimization; iii)
crashworthiness optimization, and iv) safe ship structures.
Game Theory provides a set of concepts to address
decision problems involving multiple stakeholders. In
cases where full co mpensation of costs and benefits
amongst the stakeholders cannot be guaranteed, an
economically stable solution can still be provided usin g
the theory. This solution should be fair, and, unlike the
ICAF and CATSthr criteria, it should distinguish between
design alternatives with strong safety improvements and
those with low safety improvements.
The thesis thus adopts the concept of static competitiv e
games to outline a novel design selection criterion, the
Competitive Optimum.
. Scope of the work: the basic research fields (in white) and contributions (in
grey)
For the Competitive Optimum three fundamental
conditions of selection will suffice, i.e. i) non-dominance, ii)
efficiency, and iii) maximal stakeholder satisfaction in
competitive relationships (MaSSCoR). The latter ensures
fairness.
88
MaSSCoR is based on a Nash Equilibrium solution for
static games, which provides the fairest distribution of
benefits amongst stakeholders in competitive
relationships. But since the Nash Equilibrium of a general
static game can be dominated, and hence inefficient, a
special static game is constructed assuring that the Nash
Equilibrium identifies an alternative that suffices for the
first two conditions of selection. To establish this game, we
apply multi-objective structural optimization.
Optimization allows the systematic exploration of the
design possibilities, thus providing reassurance that the
optimal alternatives that are attained are efficient. Since
classical optimization methods lack the capacity to solve
practical large-scale multi-objective problems, and the
current GA optimization also demands a large number of
functional evaluations, the thesis proposes a special GA
based on vectorization in order to enhance the
optimization process. This GA quickens the optimization
by converting all design constraints into objectives,
providing the necessary advantages in solving problems
such as the optimization of ship crashworthiness. A
systematic study is conducted on the effects of
vectorization, i.e. constraints are not only converted to
objectives, but also grouped and partially grouped to
provide strategies for approaching large-scale and time-
expensive problems. In that sense a novel ‗two-step‘
optimization procedure is proposed.
Two case studies are conducted to illustrate the
theoretical contributions that are addressed. The study on
the design of a safe double bottom for a Ro-Pax ship with
regard to grounding accidents features applications of
multi-stakeholder decision making and selection of the
89
double-bottom design that provides the best satisfaction of
stakeholders‘ preferences. Two stakeholders are
considered, the yard and the ship owner.
The study on the design of a safe tanker side structure
with respect to collision accidents, similarly to the Ro-Pax
study, features multi-stakeholder decision-making analysis
and design selection using the proposed criterion. The
study also features multi-objective optimization of the mid-
ship structure with the proposed GA to create the efficient
design alternative from which the optimal alternative can
finally be selected. The tanker is concurrently optimised
for minimum weight and for maximum crashworthiness.
Four stakeholders are identified as relevant decision
makers, i.e. the yard, the ship owner, the cargo receiver,
and the public. Risk analysis is performed, and the risk is
defined for each of the efficient alternatives generated and
for each of the four stakeholders. The related costs
resulting from an increase in crashworthiness are also
defined.
9.5.3 Limitations
The results of this thesis should be observed in the light of
the assumptions that are considered, following the desire
to focus on the early stages of the design of ship
structures.
The Competitive Optimum criterion is based on the
concept of Nash Equilibrium, which guarantees fairness
towards stakeholder preferences in design selection, and
carries the limitation that the list of assumed attributes is
not exhaustive. Furthermore, a fundamental element of
the Competitive Optimum criterion is the shared
perception of the ‗Ideal‘ among the stakeholders. The
Competitive Optimum solution will thus hold only as long
90
as all stakeholders perceive all attributes of the ‗Ideal‘
design alternative as a maximal fulfilment of their
preferences.
The stakeholder are assumed to be purely competitive,
while their preferences are a product of perfect rational
thinking with neutral attitude towards risk. This means that
a stakeholder will base decisions purely on the expected
value of an attribute. This principally holds for institutional
and industrial stakeholders, while the public is typically
more risk averse, i.e. the adverse expected attribute
values are progressively less preferred.
In this thesis, however, the public is considered
analogically to the institutional stakeholders, since their
interests are described in terms of explicit monetary
figures which is assumed to exclude emotional aspects
that bring front already mentioned risk aversion.
Risk is thus considered equivalent to expected utility6, and
is calculated explicitly following the utility theory (v
Neumann and Morgenstern 1944) as a value under
uncertainty, i.e. it is a product of consequence costs and
the probability that this consequence would occur.
The proposed GA algorithm is based on the conversion of
design constraints into objectives, i.e. vectorization. Two
types of vectorization are studied in the thesis, absolute
and Heaviside. For the optimization of tanker structures,
Heaviside vectorization was applied.
The ‗two-step‘ optimization procedure is devised on the
premise that the process of multi-objective optimization
can be split into two phases if the following two types of
objectives exist: i) easy to evaluate but difficult to optimise,
e.g. the weight of the ship structure, and ii) difficult to
91
evaluate, i.e. time-expensive but easy to optimise, e.g.
ship crashworthiness.
Independently of the fact that the proposed GA algorithm
with vectorization, through the ‗two-step‘ procedure,
enhances the optimization of large-scale problems, the
evaluation of crashworthiness during the optimization
needs to be rapid. Thus, it is evaluated for a single critical
collision scenario only. This is a major assumption, which
necessitates further validation, and for this reason the
practical outcome of the tanker case study is to be treated
accordingly.
9.5.4 The method
There are two most important parts of the proposed
design method. The
first is the generation of safe design alternatives, and the
second is the
selection of ‗the safe‘ alternative. The term ‗the safest‘ is
deliberately avoided. It strongly impedes other
characteristics of such design alternatives, as it is clearly
the one with the maximum risk reduction, but
not necessarily the one with the best distribution of costs
and benefits
amongst the stakeholders related to this risk reduction.
The method, on the other hand, results in exactly such an
alternative.
92
Scheme of the activities in the proposed methodology: leading from an
adverse event scenario, e.g. collision or grounding, new optimal design
alternatives are generated through multi-objective optimization; they are
evaluated for safety (risk analysis) and from the commercial aspect and,
finally, an alternative is selected following the multi-stakeholder decision
making and the Competitive Optimum criterion.
As mentioned, the method focuses on the structural
design of the ship, providing support to designers in
determining the best parameters of a structure they
design. It is structured on a cycle, shown in Figure 5
above, that is initiated by the analysis of the casualty that
is to be mitigated by improving safety. In cases where
collisions or grounding are to be mitigated, the ship
structure will be optimised for crashworthiness, though
without forgetting the commercial aspects of design
objectives, e.g. the weight of the ship hull. Following up on
this multi-objective optimization, the safe structures that
are generated need to be checked for stakeholder
preferences, i.e. the costs and benefits of safety
investments need to be evaluated exactly. This demands
both risk and economic analysis of the impact of the
increased crashworthiness. Finally, a safe ship structure
can be identified. As with any other method used in ship
design, this process can be repeated as many times as is
found necessary by the designers.
93
PERTEMUAN 10
Marine Propulsion
10.1 Pendahuluan
Pokok bahasan materi dalam pertemuan 10 terdiri dari:
a. Propulsion sytems
b. Enviromental effects
c. Matching engines and watercrafts. Ship resistance
d. Underwater propulsion
10.2 Tujuan Instruksional Umum
Setelah mempelajari pokok bahasan materi 10, mahasiswa mampu
memahami Propulsion sytems,Enviromental effects, Matching
engines and watercrafts. Ship resistance,Underwater propulsion
10.3 Tujuan Instruksional Khusus
Setelah mempelajari pokok bahasan materi 10, mahasiswa mampu
menjelaskan Propulsion sytems,Enviromental effects, Matching
engines and watercrafts. Ship resistance,Underwater propulsion
10.4 Skenario Pembelajaran
a. Dosen menjelaskan silabus kuliah, aturan kuliah, dan sistem
penilaian
b. Dosen menjelaskan materi kuliah
c. Diskusi dan tanya jawab dengan mahasiswa
d. Pembagian kelompok
e. Evaluasi pencapaian belajar
94
10.5. Ringkasan Materi:
10.5.1 Propulsion Systems
A propulsion system consists of three parts: an energy
source (carried aboard as animal or fuel energy, or
collected from outside as wind or solar power), an engine
that transforms it to a mechanical form, and the propulsor or
thruster (that pushes the surrounding water backwards).
Some watercraft propulsion systems: a) Oar layout in a Greek trireme. b)
Amerigo Vespucci, full-rigged ship. c) Paddle-wheel boat (diesel powered). d)
Engine room (coloured) in Queen Mary. e) Modern integrated propeller and
rudder system. f) Water-jet propulsion, showing reverse thrust. g) Hydrofoils are
usually waterjet-propelled. h) Seven-bladed screw submarine propeller. i)
Battery-powered diver propulsion device.
Types A brief grouping may be:
• Animal power, usually human rowing (Fig. 1a), but horse-
driven boats have been used (both towing with ropes from
the shore in canals, and turning a on a treadmill linked to a
propeller, aboard).
95
• Environmental power-gathering: wind power (sails), solar
power (photovoltaic). Electrical propulsion in marine
engineering refers to electric-motor-driven propellers, with
electricity produced by heat engines, and not to direct
electric sources, like batteries or solar panels, used in
some small boats, and most small underwater vessels.
• Chemical fuels carried aboard, usually a petroleum-
derivative liquid-fuel, taking advantage of the surrounding
oxidiser in the air. Marine diesel is by far the most used
fuel.
• Nuclear fuel, only used in nuclear submarines, using
highly enriched fuel (>20 % U-235) in fission-reactors,
usually of pressurised-water type (PWR), always through
steam turbines (they are similar to external combustion
engines).nergy source
The first vessels might surely have been propelled by hand
work, but it was obvious that wind has an important
entrainment effect, and the larger the frontal are the larger
the push, what originated the sail. There is evidence of
sailing boats and wooden oars in the Middle East dating
from 5000 BCE, and, in ancient Egypt by 3000 BCE, the
Nile was the main transport route, taking advantage of the
water current to go downstream, and of the prevailing
Northern winds to go upstream.
Sailing (other than downwind) requires great expertise in
varying wind and sea conditions, sometimes with
extraordinary insight (e.g. how to come back to port): both
pioneers in the Age of Discovery, Columbus in the Atlantic
and Urdaneta in the Pacific, made use of the Easterly winds
in low latitudes (Trade winds), and of the Westerly winds in
96
mid latitudes, together with the general ocean circulation
circuits (clockwise in the North hemisphere), to link distant-
continent populations and establish permanent trade
routes.
Most watercrafts (as for any other type of land, air, or space
vehicle) are presently powered by a liquid fuel stored
aboard, and a heat engine that converts the chemical
energy of the combustion of that fuel with an oxidiser, to the
mechanical energy needed to actually perform the
propulsion work. Hence, to this last respect, propulsion is
always a mechanical effect; however, mechanical
propulsion usually refers to engine-propelled vehicles, in
this case vessels, leaving aside manual (rowing) and wind
(sailing).
Types of engines
A brief grouping, more or less in chronological order,
including rowing and sailing, may be:
• Mechanical transmission from energy source to
thruster, e.g. from animal power to oars or wheels.
• Sailing, i.e. wind power propulsion acting on extended
surfaces (sails).
• Steam engine, an external combustion engine,
working in a Rankine cycle, with water as working
fluid, used in practically all ships in the 19th century,
initially with reciprocating pistons and later with
turbines (the first in 1897 with the Turbinia steamer),
and on a few vessels since then (in some very large
ships, and in nuclear submarines). The name of steam
ships are often prefixed with SS.
97
• Diesel engine, an internal combustion engine (ICE),
working in a Diesel cycle, using marine diesel or
heavy fuel oil, and used in most ships since 1930s.
also known as motor ships. Diesel engines were
limited in power for many decades, but nowadays
there are no limit in practice, with MAN/B&W and
Wärtsilä-Sulzer as the major engine manufacturers.
The name of motor ships are often prefixed with MS.
• Gas turbine, an internal combustion engine (ICE),
working in a Brayton cycle, derived from aviation
turbines, able to burn marine diesel, kerosene, or jet
fuel, are used in some fast ships (e.g. hydrofoils),
warships (for quick action), and large cruisers. The
first passenger ferry to use a gas turbine was the GTS
Finnjet, built in 1977; four years later, diesel engines
were added to decrease fuel expense, becoming the
first ship with a combined diesel-electric and gas
(CODAG) propulsion.
• Dual fuel engines, like the LNG engine, an internal
combustion engine working in a Diesel cycle, using
liquefied natural gas (LNG) as main fuel, sometimes
working in dual-fuel mode with partial marine-diesel
injection.
• Gasoline engines (ICE), used in small outboard
motors. Electric motors, which may be powered by:
o Electrical batteries, like in model ships and
submarines.
o Diesel engines. This combination of a sizeable
power source (ICE) driving an electrical generator,
with a flexible electrical connection to the electrical
motors driving the
propellers, is very convenient in spite of its extra
cost. Most large ships, particularly cruisers, use
98
electric motors in pods called azimuth thrusters
underneath to allow for 360° rotation, making the
ships far more manoeuvrable.
o Photovoltaic panels (only able to propel small
ships).
o Fuel cells, first used as air-independent propulsion
(AIP) in German Type 212 submarines since
1998, based on proton exchange membrane fuel
cells (PEMFC) of around 250 kW in total. Other
PEM-FC are used in auxiliary power units on
board ships, and more powerful molten carbonate
(MCFC) and solid oxide (SOFC) high-temperature
fuel cells are being considered for general and
especial ship propulsion (e.g. hydrogen fuelled
ships), in combination with some heat-recovery
bottom cycle, enlarging the hybrid engine type of
solutions (the first hybrid propulsion was sailing
and steam, followed by the diesel-electric
submarine, and CODAG combinations).
The first machine use for mechanical propulsion (on land
and on water) was the steam engine which, after some
trials as early as 1770, took over in 1815 with the first
crossing of the English Channel by the steamship Élise.
The first thruster used was the paddle wheel, where a
number of paddles are set around the periphery of a
partially submerged wheel. The first screw-driven ship was
Stevens' Little Juliana, in 1811, which was the first ferry,
crossing the Hudson river. In 1880, the American
passenger steamer Columbia became the first ship to utilize
incandescent light bulbs, powered by a dynamo; this was
the first application of incandescent lighting, before Edison's
99
first public power station in 1882, and soon after Edison
mastered the technology in his lab in 1878.
The main engine sits in the engine room, one of the largest
and more complex ship compartments, and the noisier (Fig.
2b). It is usually located at the aft bottom of the ship, to
minimise the shaft length to the propellers (at the stern),
though the increased use of diesel-electric propulsion
systems has released this constrain. In large ships there
are several engine rooms and engine-ancillary rooms
World's largest diesel engine, RTA96-C. b) A ship's engine room.
As an example of changing times in marine propulsion,
consider the two cruisers QM and QM2. RMS Queen Mary
was a steamer cruise of 2139 pax, built in 1936 and retired in
1967; its propulsion system delivered 120 MW (for propulsion
and hotel) from 24 Yarrow boilers that fed 4 Parson turbines,
each linked with a shaft to a screw propeller, with a service
speed of 15 m/s. RMS Queen Mary 2, built in 2003, is a part-
time cruiser and transatlantic ocean liner (the only one in
service, between Southampton and New York), of 2620 pax.
To its 117 MW of total installed power contribute four diesel
engines (Wärtsilä 16V 46C-CR) of 16.8 MW each at 500 rpm
operating on the 4-stroke cycle, and two gas turbines (GE
100
LM2500+) of 25 MW each, with the power turbine spinning at
3600 rpm, and specific fuel consumption csp=159 g/kWh and
38% thermal efficiency. It uses electrical generators and
electrical motors for propulsion (the first passenger ship with
integrated electric propulsion), with four screw-propellers pods
of 6 m in diameter spinning at 144 rpm (the forward pair fixed
and the aft two rotable 360º in azimuth, removing the need for
a rudder), each of 21.5 MW (Rolls-Royce/Alstom Mermaid),
with five blades separately bolted (the ship carries eight spare
blades). The gas turbines are not housed at or near the
engine room, deep in her hull, but instead are in a
soundproofed enclosure directly beneath the funnel, to
shorten their large air intakes. Service speed is 15 m/s.
A diesel ship's propulsion plant is similar to a ground diesel
plant (as used in cogeneration and emergency power-supply),
with a wide shaft-power range: from 10 kW to 100 MW. They
burn marine diesel oil (MDO), or heavy fuel oil (HFO) when
sulfur emissions can be tolerated (its price is nearly half of the
former). The largest the ship, the lower the engine regime; e.g.
the largest reciprocating engine can deliver 7 MW per cylinder,
which has a bore of D=1 m, stroke of L=4 m, runs at 60 rpm (1
Hz), in the two-stroke cycle, with uni-flow-scavenging, and an
efficiency of η=54% (BSFC=155 g/kWh). Slow engines spin at
<200 rpm, medium-speed engines at 200..1000 rpm, and fast
marine engines at >1000 rpm (in four-stroke cycle, with about
100 kW per cylinder).
When the ship's cargo is a fuel (oil tankers, liquefied natural-
gas carriers, LNG, or liquefied petroleum-gases carriers,
GLP), it could be used to propel the ship, but it is rarely done
because of price (heavy fuel oil is much cheaper than any
other fuel). However, LNG carriers used to be propelled by
101
water turbines to be able to burn, besides the heavy fuel, the
0.1% by mass of the load per day, due to boil-off of the
cryogenic LNG, being uneconomical to re-liquefy the boil-off.
Typical LNG engine power is about 25..30 MW, for sailing at
10 m/s, burning about 50/50 by mass of heavy-fuel and
natural-gas on the loaded trip, and about 80/20 on the ballast
trip (some LNG must be left even when on ballast, to preserve
cryogenic temperatures). Modern LNG carriers use a dual-fuel
diesel engine (burning marine diesel or natural gas in a four-
stroke engine), and electrically-driven propellers; engine
efficiency (about 40 % for diesel against 30 % for the steam
turbine) makes it more economical.
a) LNG motorised by a 32 MW steam turbines. b) Sketch of a 40 MW LNG dual-fuel
electric propulsion system (ABB).
Types of thrusters
A brief grouping may be (in chronological order of
development):
• Paddles, including oars and waterwheels (and swimming).
• Sail, or better sail-keel interaction, because without
hydrodynamic lift, aerodynamic lift in sails could never
produce ship advance against wind. Sailing upwind requires a
102
coordination of air forces on the sail with water forces on the
keel and rudder, and tacking (i.e. following a zigzag course).
• Screw propellers, by far the most used, either in bronze,
stainless steel, or fibre-reinforced polymers for small duties.
Different types are:
o Fixed pitch propeller.
o Variable pitch propeller.
o Ducted propeller.
O Azimuth propeller.
• Water jets, used in some fast ships, either powered by gas
turbines or by diesel engines.
The traditional link between the ship's main engine and the
propeller has been a mechanical shaft, supported and kept
aligned by the spring bearings, the stern tube bearings, and
the strut bearing (Fig. 4). Thrust is transmitted to the ship at
the axial thrust bearings.
Sketch of mechanical transmission in ship propulsion.
Most naval propellers are of the screw type, with 3-, 4-, or 5-
blades in the largest vessels (4 is most common), and
advancing speeds of 10..20 m/s (i.e. 20..40 kn (the knot is still
103
in widespread use), with the record is at 50 m/s. Enclosing the
propeller in a small duct (nozzle) increases the efficiency.
Notice that ship propellers sit at the rear, whereas in aircraft
they are at the front; the reason lies in the different advancing
low speeds. The rudder is behind the propellers to be effective
at low advance speeds and allow harbour manoeuvres
(although large ships may have separate perpendicular
thrusters). Notice that the rudder is the primary steering
means in ships, whereas fixed-wing aircraft have the rudder
primarily to counter adverse yaw, and turning is basically
achieved by ailerons on the far trailing-edge of each wing.
Water jet propulsion (with ducted axial fans, or with centrifugal
pumps, powered by diesel engines or gas turbines) is used in
some fast and quick-manoeuvrable ships, attaining >20 m/s.
Notice the great difference with aircraft speeds (100..250 m/s);
however, the propulsion power needed is similar, because of
the fluid-density difference in both mediums. Water propellers
are less efficient than air propellers; e.g. ship propellers may
have ηp=0.5..0.7 (against ηp=0.8 for air propellers), with the
smaller value for large tankers (which have advance ratios
J=0.2..0.4; see Propellers, aside).
Manoeuvring is greatly increased by using azimuth thruster,
i.e. a propellers placed in a pod that can be rotated to any
horizontal angle (azimuth), making a rudder unnecessary.
Most azimuth thrusters (often named azipods) are electric.
Astern propulsion is when a ship's propelling mechanism is
developing thrust in a retrograde direction, either to decelerate
and stop, or to go backwards. The usual way is by reversing
pitch in a variable-pitch propeller, but other solutions exist
104
(e.g. Fig. 1f). In aircraft propulsion it is named reverse thrust,
and in land propulsion it is named reverse gear.
The amphibious ship and helicopter carrier Juan Carlos I, the
largest naval unit ever built in Spain (26 000 t displacement,
231 m length), is powered by two diesel generators and one
gas turbine generator, driving two screw pods of 11 MW each.
The F-100 frigates (5800 t, 147 m) have two diesel generators
of 4.5 MW each for normal navigation at 9 m/s, plus two gas
turbines (GE LM-2500) of 17 MW each for advancing at 15
m/s, feeding two screw propellers.
Hydrofoils are watercraft equipped with underwater wings
(hydrofoil surfaces bellow the hull, similar to aerofoils) that
may support the vessel weight at high speed (recall that a
wing lift is almost proportional to the speed squared).The hull
is raised up and out of the water, with great reduction in drag,
and fuel consumption. Unfortunately, impact of the fast and
sharp hydrofoil surfaces, with large marine animals or floating
objects, may cause severe damage (to both). A hydroplane is
a fast motorboat, where the hull shape is such that at high
speed, the weight of the boat is supported by planing forces,
rather than simple buoyancy. There are also small electric
boats; in 2012 the PlanetSolar boat became the first ever solar
electric vehicle to circumnavigate the globe. Electrical
propulsion usually refers to the combination of a internal
combustion engine (ICE: diesel or gas turbine) and electric
motors directly driving the thruster (screw propeller or water
jet), either through a mechanical transmission (with clutch and
gears), or by an electrical generator coupled to the ICE and
electrical transmission.
105
There are some crafts that take advantage of aerodynamic
and/or hydrodynamic ground effects to support the weight of
the vehicle (they must rely on buoyancy, however, when
stopped).
There are also small watercrafts for personal use (e.g. water
scooters), some for travel at the surface, and some for
underwater use (see a diver scooter in Fig. 1i).
10.5.2 Matching Engines and Watercrafts
Two kinds of matching may be considered:
• Propulsive matching, i.e. what kind and size of engines are
needed to provide the propulsion power (or thrust) to
compensate the vessel drag at cruise, and the extra power
for acceleration and deceleration. Further engine power
must be accounted for non-propulsive duties, what may be
up to a half in large cruisers.
• Location matching and ancillary interfacing, i.e., engine
rooms, fuel tanks, funnels, etc.
Ships actually move at the same time through two fluids, water
and air, with widely different density, each contributing a
resistance to advance which, to a first approximation, is
proportional to density, so that air-resistance is often
neglected against water resistance. Hence, we are only
considering here skin friction in the submerged part of the hull,
and wave resistance, neglecting the effects of appendages
(propellers, rudders, and bilge keels), pressure drag, and air-
drag (on the superstructure and the part emerged from the
hull).
106
Ship resistance to advance depends a lot on speed, size,
wetted area, and other geometrical parameters, with a typical
share of about 60 % viscous drag (30 % skin drag, 25 % stem-
wake drag, and 5 % air drag), and 40 % wave-making drag;
however, wave drag may rise to 60 % on fast ships and
sailboats, and be under 20 % in very-large ships.
The most important non-dimensional parameters in drag
resistance are: Reynolds number (ReL=v0L/ν), Froude
number ( Fr = v0 Lg ), and the drag coefficient (cD). For
similar geometries, cD=f(Re,Fr) alone, and Froude proposed
that cD,skin=f(Re) and cD,wave=f(Fr).
10.5.3 Wave resistance
Wave-making resistance takes place on surface watercraft
(and to some extent on submarines navigating close to the
surface), and is most important in fast ships and sailboats, i.e.
for Fr~1 (say Fr>0.3). A ship moving over the surface of
undisturbed water sets up waves emanating mainly from the
bow and stern of the ship. The wave pattern consists of
divergent (or diagonal) and transverse (or longitudinal) waves
(Fig. 5), and energy is spent in its formation (which must be
supplied by the propulsion system). These waves were first
studied by Kelvin (in 1887, as a single pressure point traveling
in a straight line over the water surface), who found that
regardless of the speed of the ship, they were always
contained in the 19.5º semi-angle.
107
Ship wave pattern of transversal and divergent waves on the water surface
Total ship drag is the sum of skin friction (viscous resistance,
which monotonically increases with speed), and wave
resistance, which shows up-and-downs in its dependence with
ship speed, due to interference effects of the bow pattern with
the stern pattern (the wavelength of both transverse and
divergent waves grows with speed squared).
Increasing speed is almost always appealing in all kind of
vehicles: you arrive sooner and may do more things there,
your freight arrives sooner and you may increase your
turnaround, and, for war and emergency, you can reach to the
target and escape from the site sooner. But the power
required to propel a ship through the water is the product of
total hull resistance and ship speed, and there are a v02 term
in the skin-resistance term, and further speed effects on the
skin-drag coefficient, what finally yields a power requirement
proportional to v03 , v0
4 , or v05 . No wonder why typical service
speed in medium and large ships is about 15 m/s.
For high-speed boats, the best is to have the minimum wetted
area but a submerged propeller; different trade-offs are
achieved in SWATH-ships (small waterline area twin hull
108
ships), thin elongated bows (like catamaran), hydrofoil ships,
hovercraft, and hydroplanes. In fact, supercavitation under
water (see Supercavitation, below) can be considered a
means of reducing the wetted area of the moving object.
Large ships may reduce drag by using a bulbous bow (a
protruding bulb below the bow waterline). In a conventionally
shaped bow, a bow wave forms immediately before the bow.
When a bulb is placed below the water ahead of this wave,
water is forced to flow up over the bulb. If the trough formed
by water flowing off the bulb coincides with the bow wave, the
two partially cancel out and reduce the vessel's wake.
10.5.4 Submarines
A typical conventional submarine is about 70 m long, 7 m in
diameter, 2500 t, have a crew of some 30 people, and a 3..4
MW diesel-electric plant (composed of 2 or 3 engines, for
redundancy and load matching); non-propulsion power
requirements may reach 100 kW. The propulsion system, Fig.
6a, which may occupy up to 50 % of the pressurised hull
volume, typically operates in the following way:
• Normal operation is in fully-submerged navigation (patrol
mode), down to 200 m depth limit, with electric lead-acid
batteries supplying propulsion and housekeeping power. The
typical speed is about 2 m/s for a maximum endurance of
about 8..10 hours (0.3 MW), or a maximum speed of 15 m/s
for about half an hour (3 MW).
• Snorkel operation (or snorting), at periscope depth (about 10
m below surface), is primarily used to recharge the batteries
with the diesel engines, since the boat speed is limited to
about 3 m/s by structural strength of the snorkel mast. The
snorkel is a device which allows a submarine to operate
submerged, taking in air from above the surface (engine
109
exhaustion takes place always under water, to minimise the
thermal signature; in military surface ships the exhaust is
through a funnel, but with the flue gases diluted with air to
minimise thermal signature). A key feature is the head-valve
on top of the air-intake mast that must prevent water from
entering.
• Surface navigation, diesel powered, with electric generators
delivering a total of 3..4 MW to one or two low-rpm DC-
motors directly driving the propeller (one, or two counter-
rotating), providing a speed of up to 5..6 m/s, with endurance
limited to one or two months by fuel-tank capacity.
Propulsion power is proportional to v3, but endurance is
proportional to exp(−bv), with b≈0.35 s/m. Hidden
submerged endurance is limited by batteries energy capacity
to less than 12 h; even with an air-independent engine (see
AIP, below) it is limited by LOX mass to less than 15 days
(for a large 50 t LOX load); on nuclear-powered submarines
it is the crew endurance that sets a limit to over 3 months.
Waste disposal may endanger stealth, particularly those
mitted by the propulsion system: exhaust gases, thermal
plume, ballast, noise... Submarine propellers are relatively
large and have many blades (Fig. 1h) with a complex
curvature, intended to minimize noise while in patrol
navigation, and cavitation at high spinning rate.
Nuclear submarines are much more powerful and truly
'submarine operational' (i.e. able to travel underwater, down
to 500 m depth, at high speed for unlimited periods), though
they have a big handicap: in peace-time they are banned to
operate in most-interesting litoral regions. Their nuclear
reactors provide 100..200 MW of heat that convert to 30..70
MW of power in a steam-turbine engine. There are almost
110
400 nuclear submarines worldwide (up to 10 being replaced
each year), the largest being the Russian Typhon class (175
m long, 48 000 t submerged displacement, 75 MW power),
and the smaller being the French Rubis class (74 m long, 2
600 t submerged displacement, 7 MW power).
Submarines have two hulls: the outer hull provides a
streamlined shape to minimise resistance, whereas the inner
hull allows normal habitable pressure (around 100 kPa) by
protecting the interiors from extreme pressures at greater
ocean depths; the hulls are generally made from an alloy
which is a combination of nickel, molybdenum, and
chromium. Between these two hulls are located the ballast
tanks (Fig. 6b), which serve to change buoyancy between
surface and submerged conditions; changes in navigation
depth and attitude are dynamically performed with the
propulsion and the control planes; there are other
interconnected internal tanks, independent of ballast tanks,
to fine-control attitude and buoyancy. In case of a submarine
is unable to surface, there is a life-support system with a few
days of autonomy, and rescue vehicles (Fig. 6c) that, once
transported to a close location, can travel independently to
the downed submarine, latch onto the submarine over a
hatch, create an airtight seal so that the hatch can be
opened, and load up the crew. A diving bell may be lowered
from a support ship down to the submarine, where a similar
operation occurs. To raise the submarine, typically after the
crew has been extracted, pontoons may be placed around
the submarine and inflated to float it to the surface.
111
a) Sketch of the standard diesel-electric submarine propulsion. b) Cross-section
diagram showing the two hulls (pressurised and hydrodynamic) and the ballast
system. c) Submarine rescue vehicle.
112
PERTEMUAN 11 Avionics, Navigation, and Instrumention
11.1 Pendahuluan
Pokok bahasan materi dalam pertemuan 11 terdiri dari:
a. Avionics System Patterned After Apollo; Features and
Capabilities Unlike Any Other in the Industry
b. Central Processor Units Were Available Off the Shelf—
Remaining Hardware and Software Would
11.2 Tujuan Instruksional Umum
Setelah mempelajari pokok bahasan materi 11, mahasiswa mampu
memahami Avionics System Patterned After Apollo; Features and
Capabilities Unlike Any Other in the Industry Central Processor
Units Were Available Off the Shelf— Remaining Hardware and
Software Would
11.3 Tujuan Instruksional Khusus
Setelah mempelajari pokok bahasan materi 11, mahasiswa mampu
menjelaskan Avionics System Patterned After Apollo; Features and
Capabilities Unlike Any Other in the Industry Central Processor Units
Were Available Off the Shelf— Remaining Hardware and Software
Would
11.4 Skenario Pembelajaran
a. Dosen menjelaskan silabus kuliah, aturan kuliah, dan sistem
penilaian
b. Dosen menjelaskan materi kuliah
c. Diskusi dan tanya jawab dengan mahasiswa
d. Pembagian kelompok
e. Evaluasi pencapaian belajar
113
11.5 Ringkasan Materi:
11.5.1 Avionics System Patterned After Apollo; Features and
Capabilities Unlike Any Other in the Industry
The preceding tenets were very much influenced by NASA‘s
experience with the successful Apollo primary navigation,
guidance, and control system. The Apollo-type guidance
computer, with additional specialized input/output hardware,
an inertial reference unit, a digital autopilot, fly-by-wire thruster
control, and an alphanumeric keyboard/display unit
represented a nonredundant subset of critical functions for
shuttle avionics to perform. The proposed shuttle avionics
represented a challenge for two principal reasons: an
extensive redundancy scheme and a reliance on new
technologies.
Shuttle avionics required the development of an overarching
and extensive redundancy management scheme for the entire
integrated avionics system, which met the shuttle requirement
that the avionics system be ―fail operational/fail safe‖—i.e.,
two-fault tolerant with reaction times capable of maintaining
safe computerized flight control in a vehicle traveling at more
than 10 times the speed of high-performance military aircraft.
Shuttle avionics would also rely on new technologies—i.e.,
time-domain data buses, digital fly-by-wire flight control, digital
autopilots for aircraft, and a sophisticated software operating
system that had very limited application in the aerospace
industry of that time, even for noncritical applications, much
less for ―man-rated‖ usage. Simply put, no textbooks were
available to guide the design, development, and flight
certification of those technologies and only a modicum of off-
the-shelf equipment was directly applicable.
114
Why Fail Operational/Fail Safe?
Previous crewed spacecraft were designed to be fail safe,
meaning that after the first failure of a critical component, the
crew would abort the mission by manually disabling the
primary system and switching over to a backup system that
had only the minimum capability to return the vehicle safely
home. Since the shuttle‘s basic mission was to take humans
and payloads safely to and from orbit, the fail-operational
requirement was intended to ensure a high probability of
mission success by avoiding costly, early termination of
missions.
Early conceptual studies of a shuttle-type vehicle indicated
that vehicle atmospheric flight control required full-time
computerized stability augmentation. Studies also indicated
that in some atmospheric flight regimes, the time required for
a manual switchover could result in loss of vehicle. Thus, fail
operational actually meant that the avionics had to be capable
of ―graceful degradation‖ such that the first failure of a critical
component did not compromise the avionic system‘s capability
to maintain vehicle stability in any flight regime.
The graceful degradation requirement (derived from the fail-
operational/ fail-safe requirement) immediately provided an
answer to how many redundant computers would be
necessary. Since the computers were the only certain way to
ensure timely graceful degradation—i.e., automatic detection
and isolation of an errant computer—some type of
computerized majority-vote technique involving a minimum of
three computers would be required to retain operational status
and continue the mission after one computer failure. Thus,
four computers were required to meet the fail-operational/fail-
safe requirement. That level of redundancy applied only to the
115
computers. Triple redundancy was deemed sufficient for other
components to satisfy the fail-operational/fail-safe
requirement.
11.5.2 Central Processor Units Were Available Off the Shelf—
Remaining Hardware and Software Would Need to be
Developed
The next steps included: selecting computer hardware that
was for military use yet commercially available; choosing the
actual configuration, or architecture, of the computer(s), data
bus network, and bus terminal units; and then developing the
unique hardware and software to implement the world‘s first
two-fault-tolerant avionics.
In 1973, only two off-the-shelf computers available for military
aircraft offered the computational capability for the shuttle.
Both computers were basic processor units—termed ―central
processor units‖—with only minimal input/output functionality.
NASA selected a vendor to provide the central processor units
plus new companion input/output processors that would be
developed to specifications provided by architecture
designers. At the time, no proven best practices existed for
interconnecting multiple computers, data buses, and bus
terminal units beyond the basic active/standby manual
switchover schemes.
The architectural concept figured heavily in the design
requirements for the input/output processor and two other new
types of hardware ―boxes‖ as
116
well as the operating system software, all four of which had to
be uniquely developed for the shuttle digital data processing
subsystem. Each of those four development activities would
eventually result in products that established new limits for the
so-called ―state of the art‖ in both hardware and software for
aerospace applications.
In addition to the input/output processor, the other two new
devices were the data bus transmitter/receiver units—referred
to as the multiplex interface adapter—and the bus terminal
units, which was termed the ―multiplexer/demultiplexer.‖ NASA
designated the software as
the Flight Computer Operating System. The input/output
processors (one paired with each central processor unit) was
necessary to interface the units to the data bus network. The
numerous multiplexer/demultiplexers would serve as the
remote terminal units along the data buses to effectively
interface all the various vehicle subsystems to the data bus
117
network. Each central processor unit/input/output processor
pair was called a general purpose computer.
The multiplexer/demultiplexer was an extraordinarily complex
device that provided electronic interfaces for the myriad types
of sensors and effectors associated with every system on the
vehicle. The multiplex interface adaptors were placed internal
to the input/output processors and the
multiplexer/demultiplexers to provide actual electrical
connectivity to the data buses. Multiplex interface adaptors
were supplied to each manufacturer of all other specialized
devices that interfaced with the serial data buses. The protocol
for communication on those buses was also uniquely defined
The central processor units later became a unique design for
two reasons: within the first several months in the field, their
reliability was so poor that they could not be certified for the
shuttle ―man-rated‖ application; and following the Approach
and Landing Tests (1977), NASA found that the software for
orbital missions exceeded the original memory capacity. The
central processor units were all upgraded with a newer
memory design that doubled the amount of memory. That
memory flew on Space Transportation System (STS)-1 in
1981.
Although the computers were the only devices that had to be
quad redundant, NASA gave some early thought to simply
creating four identical strings with very limited
interconnections. The space agency quickly realized,
however, that the weight and volume associated with so much
additional hardware would be unacceptable. Each computer
needed the capability to access every data bus so the system
could reconfigure and regain capability after certain failures.
NASA accomplished such reconfiguration by software
118
reassignment of data buses to different general purpose
computers.
The ability to reconfigure the system and regain lost capability
was a novel approach to redundancy management.
Examination of a typical mission profile illustrates why NASA
placed a premium on providing reconfiguration capability.
Ascent and re-entry into Earth‘s atmosphere represented the
mission phases that required automatic failure detection and
isolation capabilities, while the majority of on-orbit operations
did not require full redundancy when there was time to
thoroughly assess the implications of any failures that
occurred prior to re-entry. When a computer and a critical
sensor on another string failed, the failed computer string
could be reassigned via software control to a healthy
computer, thereby providing a fully functional operational
configuration for re-entry.
The Costs and Risks of Reconfigurable Redundancy
The benefits of interconnection flexibility came with costs, the
most obvious being increased verification testing needed to
certify each configuration performed as designed. Those
activities resulted in a set of formally certified system
reconfigurations that could be invoked at specified times
during a mission. Other less-obvious costs stemmed from the
need to eliminate single-point failures. Interconnections
offered the potential for failures that began in one redundant
element and propagated throughout the entire redundant
system—termed a ―single-point failure‖—with catastrophic
consequences. Knowing such, system designers placed
considerable emphasis on identification and elimination of
failure modes with the potential to become single-point
failures. Before describing how NASA dealt with potential
119
catastrophic failures, it is necessary to first describe how the
redundant digital data processing subsystem was designed to
function.
Establishing Synchronicity
The fundamental premise for the redundant digital data
processing subsystem operation was that all four general
purpose computers were executing identical software in a
time-synchronized fashion such that all received the exact
same data, executed the same computations, got the same
results, and then sent the exact same time-synchronized
commands and/or data to other subsystems.
Maintenance of synchronicity between general purpose
computers was one of the truly unique features of the newly
developed Flight Computer Operating System. All four general
purpose computers ran in a synchronized fashion that was
keyed to the timing of the intervals when general purpose
computers were to query the bus terminal units for data, then
process that data to select the best data from redundant
sensors, create commands, displays, etc., and finally output
those command and status data to designated bus terminal
units.
120
NASA designed the four general purpose computer redundant
set to gracefully degrade from either four to three or from three
to two members. Engineers tailored specific redundancy
management algorithms for dealing with failures in other
redundant subsystems based on knowledge of each
subsystem‘s predominant failure modes and the overall effect
on vehicle performance.
NASA paid considerable attention to means of detecting
subtle latent failure modes that might create the potential for a
simultaneous scenario. Engineers scrutinized sensors such as
gyros and accelerometers in particular for null failures. During
orbital operation, the vehicle typically spent the majority of
time in a quiescent flight control profile such that those
sensors were operating very near their null points. Prior to re-
entry, the vehicle executed some designed maneuvers to
purposefully exercise those devices in a manner to ensure the
absence of permanent null failures. The respective design
teams for the various subsystems were always challenged to
strike a balance between early detection of failures vs.
121
nuisance false alarms, which could cause the unnecessary
loss of good devices.
Decreasing Probability of Pseudo-simultaneous Failures
There was one caveat regarding the capability to be two-fault
tolerant— the system was incapable of coping with
simultaneous failures since such failures obviously defeat the
majority-voting scheme. A nuance associated with the
practical meaning of ―simultaneous‖ warranted significant
attention from the designers. It was quite possible for internal
circuitry in complex electronics units to fail in a manner that
wasn‘t immediately apparent because the circuitry wasn‘t used
In all operations. This failure could remain dormant for
seconds, minutes, or even longer before normal activities
created conditions requiring use of the failed devices;
however, should another unrelated failure occur that created
the need for use of the previously failed circuitry, the practical
effect was equivalent to two simultaneous failures.
To decrease the probability of such pseudo-simultaneous
failures, the general purpose computers and
multiplexer/demultiplexers were designed to constantly
execute cyclic background self-test operations and
Ferreting Out Potential Single-point Failures
Engineering teams conducted design audits using a technique
known as failure modes effects analysis to identify types of
failures with the potential to propagate beyond the bounds of
the fault-containment region in which they originated. These
studies led to the conclusion that the digital data processing
subsystem was susceptible to two types of hardware failures
with the potential to create a catastrophic condition, termed a
―nonuniversal input/output error.‖ As the name implies, under
such conditions a majority of general purpose computers may
122
not have received the same data and the redundant set may
have diverged into a two-on-two configuration or simply
collapsed into four disparate members.
Engineers designed and tested the topology, components,
and data encoding of the data bus network to ensure that
robust signal levels and data integrity existed throughout the
network. Extensive laboratory testing confirmed, however, that
the two types of failures would likely create conditions
resulting in eventual loss of all four computers.
The first type of failure and the easiest to mitigate was some
type of physical failure causing either an open or a short circuit
in a data bus. Such a condition would create an impedance
mismatch along the bus and produce classic transmission line
effects; e.g., signal reflections and standing waves with the
end result being unpredictable signal levels at the receivers of
any given general purpose computer. The probability of such a
failure was deemed to be extremely remote given the robust
mechanical and electrical design as well as detailed testing of
the hardware, before and after installation on the Orbiter.
The second type of problem was not so easily discounted.
That problem could occur if one of the bus terminal units
failed, thus generating unrequested output transmissions.
Such transmissions, while originating from only one node in
the network, would nevertheless propagate to each general
purpose computer and disrupt the normal data bus signal
levels and timing as seen by each general purpose computer.
It should be mentioned that no amount of analysis or testing
could eliminate the possibility of a latent, generic software
error that could conceivably cause all four computers to fail.
Thus, the program deemed that a backup computer, with
software designed and developed by an independent
123
organization, was warranted as a safeguard against that
possibility.
This backup computer was an identical general purpose
computer designed to ―listen‖ to the flight data being collected
by the primary system and make independent calculations that
were available for crew monitoring. Only the on-board crew
had the switches, which transferred control of all data buses to
that computer, thereby preventing any ―rogue‖ primary
computers from ―interfering‖ with the backup computer.
Its presence notwithstanding, the backup computer was never
considered a factor in the fail-operational/fail-safe analyses of
the primary avionics system, and—at the time of this
publication—had never been used in that capacity during a
mission.
124
PERTEMUAN 12
Jet Fighter Aircraft
12. 1 Pendahuluan
Pokok bahasan materi dalam pertemuan 6 terdiri dari:
a. Jet Fighter Aircraft
b. A Brief History of the Development of Jet Fighter Aircraft
12. 2 Tujuan Instruksional Umum
Setelah mempelajari pokok bahasan materi 6, mahasiswa mampu
memahami Jet Fighter Aircraft dan A Brief History of the
Development of Jet Fighter Aircraft
12. 3 Tujuan Instruksional Khusus
Setelah mempelajari pokok bahasan materi 6, mahasiswa mampu
menjelaskan Jet Fighter Aircraft dan A Brief History of the
Development of Jet Fighter Aircraft
12. 4 Skenario Pembelajaran
a. Dosen menjelaskan silabus kuliah, aturan kuliah, dan sistem
penilaian
b. Dosen menjelaskan materi kuliah
c. Diskusi dan tanya jawab dengan mahasiswa
d. Pembagian kelompok
e. Evaluasi pencapaian belajar
12. 5 Ringkasan Materi:
12.5.1 Jet fighter aircraft
USE of the term ‗aircraft generations‘ first appeared in the
early 1990s and its concept applies to jet fighter aircraft
exclusively.1,2 Although use ofthis terminology remains
unofficial and imprecise, it is generally accepted that Dr.
Richard Hallion was one of the first to coin use of the term
125
when describing the leap-frogging improvements in jet fighter
design and development.
RAF Panavia Tornado GR4, a RAF Eurofighter Typhoon FGR4 and an
Indian Air Force Sukhoi Su30 MKI
In this context, ‗generations‘ denotes the ‗features‘ of jet
fighter aircraft. Some writers have described these
generations slightly differently over time 3,4 including Hallion
himself2 and this has generally led to confusion in how jet
fighter aircraft generations should be categorized. One writer
even questions the origin and timing of the use of the terms
fighter ‗generations‘, stating the first use of this terminology
actually originated in Russia during the mid-1990s, when
Russian officials there used the term during planning stages of
a Russian equivalent to the US Joint Strike Fighter.
While the terminology and categorization may remain
imprecise, the use of the term ‗generations‘ was born out of
necessity, due to a need to describe the continuous
improvements in the operational performance and features of
jet fighter aircraft, which have occurred via major advances in
airframe and engine design, avionics and weapons systems.
It should be remembered that jet fighter aircraft improvements
have not only come about as the result of upgrades and
retrospective fit-outs to existing airframes, but have also
occurred as a result of the
126
complete re-design of new airframes (made necessary when
technological innovations cannot be incorporated into existing
airframes any longer). This is known as a ‗generational shift‘.
Legacy flight including an A-10 thunderbolt II, F-4 Phantom, F-86 Sabre and P-38
Lightning, flying in formation. Photographed at Aviation Nation 2009, Nellis Air
Force Base, Las Vegas, Nevada, USA
Such major generational shifts in jet fighter aircraft design
have progressively occurred over the last 60 years, beginning
towards the end of World War II and extending into the mid
1950s – this period becoming known as the age of the ‗First
Generation‘ of jet fighters.
This article focuses on the quantum improvements in jet
fighter aircraft, commencing from the first generation to the
current, fifth generation of aircraft and beyond. It attempts to
provide a evolutionary overview of jet fighter aircraft spanning
five generations, based on their features. It also discusses
contemporary issues regarding the future of jet fighter aircraft
development, particularly considering the high costs
associated with this endeavour, the current forced reductions
in military spending due to the recent global financial crisis,
and the increasing use of more economical and durable
unmanned aerial vehicles (UAVs).
127
12.5.2 A Brief History of the Development of Jet Fighter Aircraft
Although high-powered propeller-driven aircraft dominated the
skies in every theatre of conflict during World War II, it was
Nazi Germany whom began early work on turbine-powered
(jet) aircraft design and development. The Allies, and
separately the Russians, by late WWII, had their own jet
fighter ‗R&D‘ programs well in place.
In Nazi Germany‘s case, this had reached such an advanced
state that the Luftwaffe had by Nov. 1943, a number of jet
fighters (Me 262 Sparrow, Me 263B Komet, and in 1945,
Heinkel He 162) and jet bombers (Arado Ar 234), in its military
arsenal.
Fortunately for the Allies, Hitler saw the Me 262 as a ‗blitz
bomber‘ rather than as an ‗air superiority‘ fighter, for which it
was originally designed.5
Some Me 262s, and Komet 263s did see limited action against
Allied fighters, and the results, mostly due to their speed and
firepower, were spectacular in favour of the Luftwaffe in nearly
every case, confirming Hitler‘s poor understanding of the new
jet age. However in the case of the Komet 263, its limited
endurance, temperamental powerplant and its landing gear,
posed an even bigger danger to its own pilots.
While the Germans were very innovative with their jet aircraft
designs, they were not the first nation to fly the world‘s first jet
fighter. This honour went to Robert Stanley of the US, who
flew his jet-powered American Bell XP-59A Airacomet at
Muroc, California on Oct 1, 1942 into the history books. The
other contender from Britain, the Gloster Meteor flew only six
months later, on March 5th 1943. It is important to recognise
this fact, as the Gloster Meteor (but not the Bell Airacomet),
128
was a fully equipped and capable, operational fighter aircraft
when it made its first respective flight, unlike the Me 262,
which was not.
The Bell Airacomet did see limited familiarization experience,
but its performance was deemed unsatisfactory and it was
quickly withdrawn from service. In the literature, one often
finds that the Me 262 is cited as the ‗world‘s first operational
jet fighter‘, in fact this is incorrect, as the original prototype of
the Me 262 made its first flight on April 18th 1941, using a
piston engine.
The Me262 did not fly as a jet-powered aircraft until the third
version of the plane (Me 262v3) flew on July 18th 1942,
though that flight was made without the full kit of military
equipment, and was made with a tail wheel.5 Only in its sixth
version of the series (Me262v6) did the Me 262 jet fly with all
its intended military gear and tricycle undercarriage, which
occurred on Oct. 17th 1942.
History records that the Me262, being sleek, fast and
powerful, with its swept-back wings and shark-like
appearance, was far in advance of any other aircraft of its
time. Due to its speed, it could easily evade defending Allied
fighter aircraft while attacking Allied bombers with its lethal
cannon fire. Despite its short yet brilliant wartime career, the
Me262 had changed aerial warfare permanently and it had
also heavily influenced jet fighter aircraft designs for years to
come.
Interestingly after WWII, both the Allies and the Soviets
extensively studied captured Me 262s, which aided the design
and development of their own early jet fighter aircraft. In the
129
case of the former, the design of the Me262s airofoil and slats
were incorporated into the American F-86 Sabre design.
Furthermore, when compared to earlier versions of the Gloster
Meteor, the Me262 was faster and had a more superior gun
platform. It also provided better cockpit visibility, particularly at
the sides and to the rear.
12.5.3 First Generation Jet Fighters
Commencing from mid 1940s (mostly towards the end of
WWII) and extending through to the mid 1950s (including the
1950-1953 Korean War), was the period of most research,
design and development that contributed towards first
generation fighter designs. It should also be remembered that
the period between 1945 and extending into the 1960s were
also the early years of the Cold War.
One of the main distinctions of the First generation of fighter
aircraft was that they operated at subsonic speeds in level
flight and that their jet engines were not equipped with
afterburners. These aircraft had rudimentary avionics systems
and essentially no radar or self-protection countermeasures
for engaging adversaries.
Another characteristic of First generation aircraft was that their
armament systems were also very rudimentary, as they used
a combination of machine guns and/or cannons (similarly to
piston-engined fighter aircraft of the time) and ordnance such
as largely unguided bombs and rockets. Examples of jet
fighter aircraft within this generation from the West include the
North American F-86 Sabre and later the F-100C Super
Sabre, the Grumann F9F-2B Panther, the Republic F-84
Thunderjet.
130
From the Soviets came the Mikoyan-Gureyich Mig-15 (NATO
codename Midget) and Mig17 Fresco. When the F-86 Sabre
and Mig-15 jets encountered each other during the Korean
War, this was the first time in history that jet fighter aircraft had
engaged each other in aerial combat.
12.5.4 Second Generation Jet Fighters
This covers the period from circa mid-1950s to the early
1960s. One of the main distinctions of the Second generation
of fighter aircraft was that these aircraft operated at
supersonic speeds in level flight, thanks being largely due to
advances in aerodynamics and engine design of this time.
In this period, radar warning receivers were introduced, as
well as air-to-air radar. Armament systems improved
tremendously with the introduction of both infrared and semi-
active guided missiles, and while air-to-air combat was still
undertaken mostly visually, extended engagement ranges of
radar-guided missiles began.
During this period there were two conflicts in various parts of
Asia, the first of which was the ‗Malayan Emergency‘ which
commenced in 1948 and ended in 1960.6 The second was the
first Indochina War between the French colonial forces against
the Vietnamese ‗Viet Minh‘ forces, who defeated the French.
Once the French left Vietnam, the vacuum was quickly
replaced by larger US forces (this was known as the second
IndoChina War) later better known as the Vietnam War,
lasting some 13 years.7
Although there was no air-to-air combat in the Malayan conflict
as the communist forces did not have any aircraft of their own,
allowing the RAAF to dominate the skies, the Vietnam conflict
131
was as famous for the air-to-air combat that occurred over
Vietnamese skies, as it was for the hostilities occurring on the
ground.
The third conflict, the Indo-Pakistani War of 19658, was
initially a ground war that quickly escalated into a large scale
aerial war. It saw much air-to-air combat between Indian Air
Force jets such as Vampire FB Mk 52s, Dassault Mystere IVs,
Hawker Hunters, as well as Folland Gnat jet fighters pitted
against the Pakistani Air Force‘s mainly F-86 Sabres and F-
104 Starfighters.
Examples of jet fighter aircraft within this generation include,
from the West, Hawker T7 Hunter, the Lockheed F-104
Starfighter, the Dassualt IV Mystere, and from the Soviets the
Mikoyan-Gureyich Mig-19 Farmer and Mig-21 Fishbed.
12.5.5 Third Generation Jet Fighter
This covers the period circa 1960 to 1970. Major
advancements made it possible for jet fighter aircraft to carry
out aerial combat engagements that moved beyond visual
range, or in other words, it was no longer necessary to visually
identify enemy jet fighters in order to attack them. This was
due to the enhancement of sophisticated radar systems such
as Doppler radar, which permitted a ‗look-down and shoot-
down capability‘. It was also the time in which functionality of
the ‗multi-role‘ jet fighter first appeared.
This period also saw the introduction of semi-active guided
radio frequency missiles such as the advanced Sparrow AIM-7
and the Apex AA-7, in addition to off-bore sight targeting
systems. Overall, this period saw significant improvements in
weapons systems, avionics, but also in jet fighter aircraft
manoeuvrability due to much sleeker airframe designs.
132
The period 1962 to 1975 saw the world witnessing the horrors
of the Vietnam war, which became a major proving ground for
jet fighter aircraft of the West. Two commonly used examples
flown were the McDonnell-Douglas F4 Phantom and the F-104
Thunderjet, which were pitted against their Eastern Bloc
adversaries, mainly the Mig-21 Fishbed.
Other examples of jet fighter aircraft of this generation include,
from the West, the Sepecat MK1A Jaguar, BAc Harrier,
Northrop F-5 Tiger, the Convair F-106 Delta Dart and the
Dassault Mirage F-I, and from the Soviets the Sukhoi Su-17,
Su-20, Su-Su-25 Frogfoot, and Mig-23 and Mig-25.
133
PERTEMUAN 13 Flotation, hydrostatics, and ship stability
13.1 Pendahuluan
Pokok bahasan materi dalam pertemuan 13 terdiri dari:
a. Buoyancy and Stability
b. Archimedes principle
c. The gentle art of balloning
d. Stability of floating bodies
13. 2 Tujuan Instruksional Umum
Setelah mempelajari pokok bahasan materi 13, mahasiswa mampu
memahami Buoyancy and Stability, Archimedes principle,The
gentle art of balloning, Stability of floating bodies
13. 3 Tujuan Instruksional Khusus
Setelah mempelajari pokok bahasan materi 13, mahasiswa mampu
menjelaskan Buoyancy and Stability,Archimedes principle,The
gentle art of balloning, Stability of floating bodies
13. 4 Skenario Pembelajaran
a. Dosen menjelaskan silabus kuliah, aturan kuliah, dan sistem
penilaian
b. Dosen menjelaskan materi kuliah
c. Diskusi dan tanya jawab dengan mahasiswa
d. Pembagian kelompok
e. Evaluasi pencapaian belajar
13. 5 Ringkasan Materi:
13.5.1 Bouyancy and stability
Fishes, whales, submarines, balloons and airships all owe
their ability to float to buoyancy, the lifting power of water and
air. The understanding of the physics of buoyancy goes back
as far as antiquity and probably sprung from the interest in
134
ships and shipbuilding in classic Greece. The basic principle
is due to Archimedes. His famous Law states that the
buoyancy force on a body is equal and oppositely directed to
the weight of the fluid that the body displaces. Before his
time it was thought that the shape of a body determined
whether it would sink or float.
The shape of a floating body and its mass distribution do,
however, determine whether it will float stably or capsize.
Stability of floating bodies is of vital importance to
shipbuilding
— and to anyone who has ever tried to stand up in a small
rowboat. Newtonian mechanics not only allows us to derive
Archimedes‘ Law for the equilibrium of floating bodies, but
also to characterize the deviations from equilibrium and
calculate the restoring forces. Even if a body floating in or on
water is in hydrostatic equilibrium, it will not be in complete
mechanical balance in every orientation, because the center
of mass of the body and the center of mass of the displaced
water, also called the center of buoyancy, do not in general
coincide.
The mismatch between the centers of mass and buoyancy
for a floating body creates a moment of force, which tends to
rotate the body towards a stable equilibrium. For submerged
bodies, submarines, fishes and balloons, the stable
equilibrium will always have the center of gravity situated
directly below the center of buoyancy. But for bodies floating
stably on the surface, ships, ducks, and dumplings, the
center of gravity is mostly found directly above the center of
buoyancy. It is remarkable that such a configuration can be
stable. The explanation is that when the surface ship is tilted
away from equilibrium, the center of buoyancy moves
instantly to reflect the new volume of displaced water.
135
Provided the center of gravity does not lie too far above the
center of buoyancy, this change in the displaced water
creates a moment of force that counteracts the tilt.
13.5.2 Archimedes priciple
Mechanical equilibrium takes a slightly different form than
global hydrostatic equilibrium (2.18) on page 27 when a body
of another material is immersed in a fluid. If its material is
incompressible, the body retains its shape and displaces an
amount of fluid with exactly the same volume. If the body is
compressible, like a rubber ball, the volume of displaced fluid
will be smaller. The body may even take in fluid, like a
sponge or the piece of bread you dunk into your coffee, but
we shall disregard this possibility in the following
A body which is partially immersed with a piece inside and
another outside the fluid may formally be viewed as a body
that is fully immersed in a fluid with properties that vary from
place to place. This also covers the case where part of the
body is in vacuum which may be thought of as a fluid with
vanishing density and pressure.
Let the actual, perhaps compressed, volume of the immersed
body be V with surface S. In the field of gravity an
unrestrained body with mass density body is subject to two
forces: its weight
z
FG D body g dV;
V
and the buoyancy due to pressure acting on its surface,
I
FB D p dS :
136
In a constant gravitational field, g.x/ D g0, everything
simplifies. The weight of the body and the buoyancy force
become instead,
FG D Mbody g0; FB D Mfluid g0:
Since the total force is the sum of these contributions, one
might say that buoyancy acts as if the displacement were
filled with fluid of negative mass Mfluid. In effect the
buoyancy force acts as a kind of antigravity.
The total force on an unrestrained object is now,
F D FG C FB D .Mbody Mfluid/g0:
If the body mass is smaller than the mass of the displaced
fluid, the total force is directed upwards, and the body will
begin to rise, and conversely if the force is directed
downwards it will sink. Alternatively, if the body is kept in
place, the restraints must deliver a force F to prevent the
object from moving.
In constant gravity, a body can only hover motionlessly inside
a fluid (or on its surface) if its mass equals the mass of the
displaced fluid,
A fish achieves this balance by adjusting the amount of water
it displaces (Mfluid) through contraction and expansion of its
body by means of an internal air-filled bladder. A submarine,
in contrast, adjusts its mass (Mbody) by pumping water in
and out of ballast tanks
137
13.5.3 The gentle art of ballooning
The first balloon flights are credited to the Montgolfier
brothers who on November 21, 1783 flew an untethered
manned hot-air balloon, and to Jacques Charles who on
December 1 that same year flew a manned hydrogen gas
balloon (see fig. 3.1). In the beginning there was an intense
rivalry between the advocates of Montgolfier and Charles
type balloons, respectively called la Montgolfiere` and la
Charliere`, which presented different advantages and
dangers to the courageous fliers. Hot air balloons were
easier to make although prone to catch fire, while hydrogen
balloons had greater lifting power but could suddenly
explode. By 1800 the hydrogen balloon had won the day,
culminating in the huge (and dangerous) hydrogen airships
of the 1930s. Helium balloons are much safer, but also
much more expensive to fill. In the last half of the twentieth
century hot-air balloons again came into vogue, especially
for sports, because of the availability of modern strong
lightweight materials (nylon) and fuel (propane).
Let M denote the mass of the balloon at height z above the
ground. This includes the gondola, the balloon skin, the
payload (passengers), but not the gas (be it hot air,
hydrogen or helium). The mass of the balloon can diminish
if the balloon captain decides to throw out stuff from the
gondola to increase its maximal height, also called the
ceiling, and often sand bags are carried as ballast for this
purpose. The condition (3.7) for the balloon to float stably at
height z above the ground now takes the form,
138
where 0 the density of the gas, is the density of the
displaced air, and V the volume of the gas at height z. On
the right we have left out the tiny buoyancy VM due to the
volume VM of the material of the balloon itself. If the left-
hand side of this equation is smaller or larger than the right-
hand side, the balloon will rise or fall.
Contemporary pictures of the first flights of the Montgolfier hot air
balloon (left) and the Charles hydrogen balloon (right). The first ascents
were witnessed by huge crowds. Benjamin Franklin, scientist and one
of the founding fathers of the US, was present at the first Montgolfier
ascent and was deeply interested in the future possibilities of this
invention, but did not live to see the first American hot air balloon flight
in 1793.
A modern large hydrogen or helium balloon typically begins
its ascent being only partially filled, assuming an inverted
tear-drop shape. During the ascent the gas expands because
of the fall in ambient air pressure, and eventually the balloon
becomes nearly spherical and stops expanding (or bursts)
because the ―skin‖ of the balloon cannot stretch further. To
avoid bursting the balloon can be fitted with a safety valve.
Since the density of the displaced air falls with height, the
balloon will eventually reach a ceiling where it would hover
139
permanently if it did not lose gas. In the end no balloon stays
aloft forever.
13.5.4 Stability of Floating bodies
Although a body may be in buoyant equilibrium, such that
the total force composed of gravity and buoyancy vanishes,
F D FG C FB D 0, it may still not be in complete mechanical
equilibrium. The total moment of all the forces acting on the
body must also vanish; other-wise an unrestrained body will
necessarily start to rotate. In this section we shall discuss
the mechanical stability of floating bodies, whether they
float on the surface, like ships and ducks, or float
completely submerged, like submarines and fish. To find
the stable configurations of a floating body, we shall first
derive a useful corollary to Archimedes‘ Principle
concerning the moment of force due to buoyancy.
Moments of gravity and buoyancy
The total moment is like the total force a sum of two
terms,
with one contribution from gravity,
and the other from pressure, the moment of buoyancy,
If the total force vanishes, F D 0, the total moment will be
independent of the origin of the coordinate system, as
may be easily shown.
140
Assuming again that the presence of the body does not
change the local hydrostatic bal-ance in the fluid, the
moment of buoyancy will be independent of the nature of
the material inside V . If the actual body is replaced by an
identical volume of the ambient fluid, this fluid volume
must be in total mechanical equilibrium, such that both the
total force as well as the total moment acting on it have to
vanish. Using that MfluidG C MB D 0, we get
and we have in other words shown that
the moment of buoyancy is equal and opposite to the
moment of the weight of the dis-placed fluid.
This result is a natural corollary to Archimedes‘ principle,
and of great help in calculating the buoyancy moment. A
formal proof of this theorem, starting from the local
equation of hydrostatic equilibrium, is found in problem.
Ship stability
Sitting comfortably in a small rowboat, it is fairly obvious
that the center of gravity lies above the center of
buoyancy, and that the situation is stable with respect to
small movements of the body. But many a fisherman has
learned that suddenly standing up may compromise the
stability and throw him out among the fishes. There is, as
we shall see, a strict limit to how high the center of gravity
may be above the center of buoyancy. If this limit is
violated, the boat becomes unstable and capsizes. As a
practical aid to the captain, the limit is indicated by the
141
position of the so-called metacenter, a fictive point usually
placed on the vertical line through the equilibrium
positions of the centers of buoyancy and gravity (the
‗mast‘). The stability condition then requires the center of
gravity to lie below the metacenter (see the margin figure).
Initially, we shall assume that the ship is in complete
mechanical equilibrium with vanish-ing total force and
vanishing total moment of force. The aim is now to
calculate the moment of force that arises when the ship is
brought slightly out of equilibrium. If the moment tends to
turn the ship back into equilibrium, the initial orientation is
stable, otherwise it is unstable.
The Flying Enterprise (1952). A body can float stably in many
orientations, depending on the position of its center of gravity. In this
case the list to port was caused by a shift in the cargo which moved
the center of gravity to the port side. The ship and its lonely captain
Carlsen became famous because he stayed on board during the
storm that eventually sent it to the bottom. Photograph courtesy
Politiken, Denmark, reproduced with permission
142
Center of roll
Most ships are mirror symmetric in a plane, but we shall
be more general and consider a ―ship‖ of arbitrary shape.
In a flat earth coordinate system with vertical z-axis the
waterline is naturally taken to lie at z D 0. In the waterline
the ship covers a horizontal region A of arbitrary shape.
The geometric center or area centroid of this region is
defined by the average of the position,
The area A of the ship in the wa-terline may be of quite arbitrary
shape.
where dA D dx dy is the area element. Without loss of
generality we may always place the coordinate system such
that x0 D y0 D 0. In a ship that is mirror symmetric in a vertical
plane the area center will also lie in this plane.
To discover the physical significance of the centroid of the
waterline area, the ship is tilted (or ―heeled‖ as it would be in
maritime language) through a tiny positive angle around the x-
axis,
such that the equilibrium waterline area A comes to lie in the
plane z D y. The net change •V in the volume of the displaced
water is to lowest order in given by the difference in volumes of
the two wedge-shaped regions between new and the old
y
6
. .
. . .
. ...
. .
..
. . . .
...
.. -
x
.
.
. A .
..
. . . . . . . . . .
. .
143
waterline. Since the displaced water is removed from the wedge
at y > 0 and added to the wedge for y < 0, the volume change
becomes
Tilt around the x-axis. The change in displacement consists in
moving the water from the wedge to the right into the wedge to
the left.
In the last step we have used that the origin of the coordinate
system coincides with the centroid of the waterline area (i.e. y0
D 0). There will be corrections to this result of order 2 due to the
actual shape of the hull just above and below the waterline, but
they are disregarded here. To leading order the two wedges
have the same volume.
The Queen Mary 2 set sail on its maiden voyage on January 2, 2004. It was
at that time the world‘s largest ocean liner with a length of 345 m, a height of
72 m from keel to funnel, and a width of 41 m. Having a draft of only 10 m,
its superstructure rises an impressive 62 m over the waterline. The low
average density of the superstructure, including 2620 passengers and 1253
144
crew, combined with the high average density of the 117 megawatt engines
and other heavy facilities close to the bottom of the ship nevertheless allow
the stability condition (3.28) to be fulfilled. Photograph by Daniel Carneiro.
Since the direction of the x-axis is quite arbitrary, the conclusion
is that the ship may be heeled around any line going through
the centroid of the waterline area without any first order change
in volume of displaced water. This guarantees that the ship will
remain in buoyant equilibrium after the tilt. The centroid of the
waterline area may thus be called the ship‘s center of roll.
145
PERTEMUAN 14
Fundamentals of Systems Engineering
14.1 Pendahuluan
Pokok bahasan materi dalam pertemuan 14 terdiri dari:
a. Nasa Design Definition Process
b. Multidisciplinary Design Optimization
c. Concurrent Design Facilities (CDF)
d. Critical Design Review (CDR)
14.2 Tujuan Instruksional Umum
Setelah mempelajari pokok bahasan materi 14, mahasiswa mampu
memahami Nasa Design Definition Process, Multidisciplinary Design
Optimization, Concurrent Design Facilities (CDF), Critical Design
Review (CDR)
14.3 Tujuan Instruksional Khusus
Setelah mempelajari pokok bahasan materi 14, mahasiswa mampu
menjelaskan Nasa Design Definition Process, Multidisciplinary
Design Optimization, Concurrent Design Facilities (CDF), Critical
Design Review (CDR)
14.4 Skenario Pembelajaran
a. Dosen menjelaskan silabus kuliah, aturan kuliah, dan sistem
penilaian
b. Dosen menjelaskan materi kuliah
c. Diskusi dan tanya jawab dengan mahasiswa
d. Pembagian kelompok
e. Evaluasi pencapaian belajar
14.5. Ringkasan Materi:
14.5.1 Design Solution Definition Process
146
The Design Solution Definition Process is used to
translate the outputs of the Logical Decomposition
Process into a design solution definition
Design Solution Importance
Define solution space
Develop design alternatives
Trade studies to analyze
Alternate Design
Cost, performance, schedule
Select Design Solution
Drive down to lowest level
Identify enabling products
147
Design Solution Definition – Best Practice Process Flow
Diagram
Design Solution Definition – Important Design
Considerations
148
Producibility vs. Total Cost
Concept Question
14.5.2 Multidisclinary Design Optimization
MDO defined as (AIAA MDO Tech Committee):
―an evolving methodology, i.e. a body of methods,
techniques, algorithms, and related application practices,
for design of engineering systems coupled by physical
phenomena and involving many interacting subsystems
and parts.‖
149
Conceptual Components of MDO (Sobieksi ‗97)
Mathematical Modeling of a System
Design Oriented Analysis
Approximation Concepts
System Sensitivity Analysis
Classical Optimization Procedures
Human Interface
MDO - Motivation
MDO - Roots
150
MDO - Example
Simple example of interdependency
MDO – Method: Bi-Level Integrated System Synthesis
Formulation of Design System: Supersonic Business Jet
Example
151
Subsystem Optimization (SSOPT)
Subsystem Optimization (SSOPT)
152
Subsystem Optimization (SSOPT)
System Optimization (SOPT)
153
154
MDO - Challenges
14.5.3 Concurrent design approach
to perform a system engineering study for a project. Key
elements for a CDF:
155
environment (including A/V and software)
knowledge management
Challenges in an academic environment
all project must be synchronized with academic
schedule
CDF in industrial setting
Design centers in Space Agencies
JPL: TeamX
studies have shown than cost estimations of TeamX
were within 10% of the final mission cost
rapid assessment of proposals
ESTEC (ESA)
all of the future projects at ESA are going through the
ESA CDF
Others
156
Most NASA centers, ASI, CNES, commercial
applications of the idea (painting, shipbuilding,
medical devices)
Benefits
improvements on quality for redesigned
products
very quick turnaround for ideas
better cost estimates
increased creativity and productivity in a
company
Example of Cubesat Design in J-CDS
Design of a suborbital space plane in CDF
157
Requirements
Level 1 requirements.
Reach an altitude of at least 100km over sea level
Zero G-phase flight phase of several minutes
Passenger vehicle carrying 6 people
Level 2 requirements
Safety: load limit 6 g
Spacecraft shall be controllable at any time
Customer experience: view on earth’s curvature
and atmosphere
Environment: The spacecraft’s impact on
environment should be as small as possible
Mass budget: The spacecraft’s mass should not
exceed 11.6t (with propellants)
CDF Design: K1000
158
Requirements verification by modeling
159
PERTEMUAN 15
STUDI KASUS
160
PERTEMUAN 16
UAS