1. A REPORT ON
FOR
ASSEMBLY & OVERHAUL DEPARTMENT (ADOUR - MK871), ENGINE
DIVISION, HAL, BANGALORE
IN FULFILLMENT OF INTERNSHIP PROGRAM FOR CAREER DEVELOPMENT
DURING THE PERIOD 11H
JUNE TO 15TH
JULY 2014
BY
MONISH U R – 1MS11ME102
M S RAMAIAH INSTITUTE OF TECHNOLOGY

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CONTENTS
SL. NO. TITLE PAGE NO.
1. Hindustan Aeronautics Limited 02
2. Engine Division, HAL 03
3. Modern Management Tools Used 05
4. Practical applications related to subjects Studied 07
5. Nature of work done during Internship 08
6. Benefits of Internship 08
5. Introduction to Jet Propulsion 09
6. Brayton Cycle 10
7. Jet Engines 11
8. Turbo Fan Engines 14
9. The Adour MK 871 Engine 17
10. Assembly of Adour MK871 21
11. Balancing of Rotating masses 22
12. Automation of Dynamic Balancing 25
13. C Programming Language 26
14. Algorithm of the C/C++ Program 27
15. Verification of the Program 28
16 Conclusion 31
17. Bibliography 32

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HINDUSTAN AERONAUTICS LIMITED
Hindustan Aeronautics Limited (HAL) came into existence on 1st October
1964. The Company was formed by the merger of Hindustan Aircraft Limited
with Aeronautics India Limited and Aircraft Manufacturing Depot, Kanpur.
The Company traces its roots to the pioneering efforts of an industrialist with
extraordinary vision, the late Seth Walchand Hirachand, who set up Hindustan
Aircraft Limited at Bangalore in association with the erstwhile princely State
of Mysore in December 1940. The Government of India became a shareholder
in March 1941 and took over the Management in 1942.
Today, HAL has 19 Production Units and 10 Research & Design Centers in 8 locations in India. The
Company has an impressive product track record - 15 types of Aircraft/Helicopters manufactured
with in-house R & D and 14 types produced under license. HAL has manufactured over
3658 Aircraft/Helicopters, 4178 Engines, and Upgraded 272 Aircraft and overhauled over 9643
Aircraft and 29775 Engines.
HAL has been successful in numerous R & D programs developed for both Defense and Civil
Aviation sectors. HAL has made substantial progress in its current projects:
 Advanced Light Helicopter – Weapon System Integration (ALH-WSI)
 Tejas - Light Combat Aircraft (LCA)
 Intermediate Jet Trainer (IJT)
 Light Combat Helicopter (LCH)

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THE ENGINE DIVISION, HAL
The Engine Division, which is ISO-9002 certified, was set up in 1957 to manufacture Orpheus turbo
jet engines under license from Rolls Royce. In 1959, another license agreement was signed with
Rolls Royce to manufacture Dart engines to power HS-748 passenger aircraft and overhaul Avon
engines fitted on Canberra & Hunter aircraft. Since then, the division has grown from strength to
strength. It is now engaged in the manufacture of Artouste engines for Chetak/Cheetah
helicopters, Adour engines for Jaguar aircraft and Garrett engines for Dornier aircraft. Engine
division also undertakes repair and overhaul of various aero engines operated by Indian Air force,
Indian Navy, Indian Army, Coast Guard, Border Security Force, Corporate sector, State Government
and other civil customers. The division has manufactured more than 2,100 aero engines and
overhauled & repaired 11,000 engines.
The division, during four decades of its existence, has acquired state-of-art-technologies for
manufacture, repair and overhaul of engines. It has a well-equipped CNC shop comprising over 25
machine tools. Facilities also include Electron Beam Welding, vacuum Brazing, Electric Discharge /
Chemical forming machines and others. The division has also set up shops for special coating
processes to combat high temperature and atmospheric corrosion conditions, protection against
surface erosions, such as Plasma Spray, Aluminium Silicon diffusion coating, Sermetal coating.
Engine and Test bed R & D Centre, which is part of the Engine Division, has specialized in the
development of small Gas Turbines & Engine Test Beds. The ETBRDC is equipped with necessary
modern infrastructures. The R&D Centre has developed a gas turbine engine for Pilotless Target
Aircraft and jet Fuel Starter for starting the engine of Light Combat Aircraft. The R & D Centre has
also designed and installed engine test beds for Russian and western origin aero engines on turnkey
basis.
KAVERI ENGINE
Kaveri, the designated engine for LCA, is being developed by GTRE, Bangalore. Various divisions
of HAL are involved in the development and certification. The engine will be manufactured at
engine division, HAL. The materials for engine components include high strength super alloy such as
Inconel on the hot end side and TI-64 on the cold end. The engine is twin spool, by pass type
designed to provide dry thrust of 5291 kg reheat thrust of 8264 kg.

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ENGINES FOR AJT, IJT AND ALH
The engines for advanced Jet trainer project and intermediate Jet trainer project will also be
manufactured by engine division in the near future. Further, the division will be participating in the
co-design & co-production of engine for Advanced Light Helicopters.

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MODERN MANAGEMENT TOOLS USED
Engine Division, HAL practices the following modern management techniques on its shop floor to
ensure maximum efficiency:
LEAN MANUFACTURING
Lean manufacturing or lean production, often simply "lean", is a systemic method for the elimination
of waste ("Muda") within a manufacturing process. Lean also takes into account waste created
through overburden ("Muri") and waste created through unevenness in workloads ("Mura").
Working from the perspective of the client who consumes a product or service, "value" is any action
or process that a customer would be willing to pay for. Essentially, lean is centered on making
obvious what adds value by reducing everything else.
KAIZEN
Kaizen, Japanese for "change for better". When used in the business sense and applied to the
workplace, kaizen refers to activities that continually improve all functions and involve all
employees from the CEO to the assembly line workers. It also applies to processes, such as
purchasing and logistics that cross organizational boundaries into the supply chain. It has been
applied in healthcare, psychotherapy, life-coaching, government, banking, and other industries.
By improving standardized activities and processes, kaizen aims to eliminate waste (see lean
manufacturing). Kaizen was first implemented in several Japanese businesses after the Second World
War, influenced in part by American business and quality management teachers who visited the
country. It has since spread throughout the worl and is now being implemented in environments
outside of business and productivity.
5S
5S is the name of a workplace organization method that uses a list of five Japanese words: seiri,
seiton, seiso, seiketsu, and shitsuke. Transliterated or translated into English, they all start with the
letter "S". The list describes how to organize a work space for efficiency and effectiveness by
identifying and storing the items used, maintaining the area and items, and sustaining the new order.
The decision-making process usually comes from a dialogue about standardization, which builds
understanding among employees of how they should do the work.
There are five 5S phases: They can be translated from the Japanese as "sort", "straighten", "shine",
"standardize", and "sustain".
Seiri (sort)
 Remove unnecessary items and dispose of them properly
 Make work easier by eliminating obstacles
 Reduce chance of being disturbed with unnecessary items
 Prevent accumulation of unnecessary items
 Evaluate necessary items with regard to cost or other factors
 Remove all parts not in use
 Segregate unwanted material from the workplace
 Need fully skilled supervisor for checking on regular basis

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Seiton (Systematic Arrangement)
 Can also be translated as "set in order" , "straighten" or "streamline"
 Arrange all necessary items so they can be easily selected for use
 Prevent loss and waste of time
 Make it easy to find and pick up necessary items
 Ensure first-come-first-served basis
 Make workflow smooth and easy
 All above work should be on regular base
Seiso (Shine)
 Can also be translated as "sweep", "sanitize", "shine", or "scrub"
 Clean your workplace completely
 Use cleaning as inspection
 Prevent machinery and equipment deterioration
 Keep workplace safe and easy to work
 keep work place clean
Seiketsu (Standardize)
 Standardize the best practices in the work area.
 Maintain high standards of housekeeping and workplace organization at all times.
 Maintain orderliness. Maintain everything in order and according to its standard.
 Everything in its right place.(Chilled totes in chilled area, Dry totes in dry area.)
 Every process has a standard
Shitsuke (Sustain)
 To keep in working order
 Also translates as "do without being told" (though this doesn't begin with S)
 Perform regular audits
 Training and Discipline
 Training is goal oriented process. its result feedback is necessary monthly

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PRACTICAL APPLICATIONS RELATED TO SUBJECTS
STUDIED
The following pages give a detailed description of the concepts I had studied as part of my
internship. These concepts helped me acquire a detailed understanding about the working of Jet
engines in general and Adour MK871 in particular. As part of my internship tasks I had to automate
the dynamic balancing process. This helped achieve a greater understanding about balancing of
rotating components. HAL also practices modern management techniques which helped me get a
practical insight to the concepts of Lean manufacturing. Hence, the internship helped me get a
practical understanding about the following subjects:
 Jet Propulsion
 Brayton cycle
 Balancing of rotating Masses
 Lean Manufacturing
 Kaizen
 5S

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NATURE OF WORK DONE DURING INTERNSHIP
My internship work at Engine Division, HAL was broadly in two areas. Primary area of focus of my
internship was to develop a C program that would automate the calculation process of dynamic
balancing of engine modules. This particular task involved me coding on a designated computer
under the guidance of my in-charge. The coding of the program took several days to be completed.
After the coding was completed, the results were first verified according to data supplied by the
designer to HAL. Once this was complete, the program was tested to check for compliance with all
the modules of the engine. This is shown subsequently in the report.
Before I was tasked to balancing of engine modules, I was told to get I detailed understanding about
the assembly procedures, module testing, engine testing and also the various manufacturing
processes used in making the components for the engine. This task was mainly observatory. I had to
go from department to department and understand the various processes being used. In the last few
days of my internship I was told to give guidance to other interns who had come to Adour MK871
Assembly shop for observation. These tasks can broadly describe the nature of my work at Adour
MK871 Assembly Division, Engine Division, HAL, Bangalore.
BENEFITS OF INTERNSHIP
The internship has helped me immensely in understanding of various concepts which I had learned at
college. It has given me practical insight into the working of Jet engines and the various stages
involved in the manufacture, assembly and overhauling. The internship had given me an
understanding of the functioning of an industry and the way in which human resource and shop floor
management is carried out. The internship has also helped me gain experience in a prospective career
path and given me some invaluable industry contacts which will greatly help me in the future. It has
also helped me greatly in improving my communication skills and also, in interacting with others in
a professional environment. I also, believe this internship has given me work experience that would
help me in seeking a job.

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INTRODUCTION TO JET PROPULSION
The basic concept of jet propulsion comes from the simple concept or an idea that if you have a
device in which a certain amount of working fluid and in our case this working fluid is almost,
invariably air. As a result of which, all jet propulsion devices that we are talking about are essentially
air breathing engines. These air breathing engines have propulsive method by which this is illustrated
in this picture.
In this method, the air is inducted into a propulsive device and this working medium is then
accelerated through the device and the air is exited from the device with slightly higher velocity. As
a result of this the working medium actually acquires a change of momentum. This change of
momentum is what finally manifests itself, in the form of force or more specifically the action of the
exhaust jet.
The propulsive device creates the reaction, which is the propulsive force or what we would more
specifically we always referring to it from now onwards as thrust. The thrust is a result essentially or
a reaction to the change of momentum that occurs across the propulsive device. This is the basic
understanding on which all propulsive devices that we are looking at today would be essentially
based on.
Now, this requires that the air which is again our working medium going into the propulsive device
has certain properties in terms of pressure, temperature and velocity. It goes out with another set of
properties again another set of pressure, temperature and velocity. A change of these properties is
what produces the change of momentum. Basically, the change of momentum that we are looking at
refers to the change of velocity; velocity as you know has a magnitude and a direction.
The direction as shown in this picture, in the same line that means the incoming velocity and the
outgoing velocity are exactly in the same line. As a result of which the action of the exhaust velocity
and the reaction produces a thrust in the same line in which the velocities have come in and gone out.
As a result of which a thrust is produced in the line of acting on of the production of exhaust velocity
or exhaust jet more specifically.

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BRAYTON CYCLE
The Brayton cycle is a thermodynamic cycle that describes the workings of a constant pressure heat
engine. Gas turbine engines and air breathing jet engines use the Brayton Cycle. Although the
Brayton cycle is usually run as an open system, it is conventionally assumed for the purposes
of thermodynamic analysis that the exhaust gases are reused in the intake, enabling analysis as a
closed system.
IDEAL BRAYTON CYCLE:
1. Isentropic process - ambient air is drawn into the compressor, where it is pressurized.
2. isobaric process - the compressed air then runs through a combustion chamber, where fuel is
burned, heating that air—a constant-pressure process, since the chamber is open to flow in
and out.
3. Isentropic process - the heated, pressurized air then gives up its energy, expanding through a
turbine (or series of turbines). Some of the work extracted by the turbine is used to drive the
compressor.
4. Isobaric process - heat rejection (in the atmosphere).
ACTUAL BRAYTON CYCLE:
1. Adiabatic process - compression.
2. Isobaric process - heat addition.
3. Adiabatic process - expansion.
4. Isobaric process - heat rejection.

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JET ENGINES
A jet engine is a reaction engine discharging a fast moving jet that generates thrust by jet propulsion
in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets,
turbofans, rockets, ramjets, and pulse jets. In general, jet engines are combustion engines but non-
combusting forms also exist.
In common parlance, the term jet engine loosely refers to an internal combustion air breathing jet
engine (a duct engine). These typically consist of an engine with a rotary (rotating) air compressor
powered by a turbine ("Brayton cycle"), with the leftover power providing thrust via a propelling
nozzle. Jet aircraft use these types of engines for long-distance travel. Early jet aircraft used turbojet
engines which were relatively inefficient for subsonic flight. Modern subsonic jet aircraft usually use
high-bypass turbofan engines. These engines offer high speed and greater fuel efficiency than piston
and propeller aero engines over long distances.
There are a large number of different types of jet engines, all of which achieve forward thrust
from the principle of jet propulsion.
TURBINE POWERED
Gas turbines are rotary engines that extract energy from a flow of combustion gas. They have an
upstream compressor coupled to a downstream turbine with a combustion chamber in-between. In
aircraft engines, those three core components are often called the "gas generator." There are many
different variations of gas turbines, but they all use a gas generator system of some type.
TURBOJET
A turbojet engine is a gas turbine engine that works by compressing air with an inlet and a
compressor (axial, centrifugal, or both), mixing fuel with the compressed air, burning the mixture in
the combustor, and then passing the hot, high pressure air through a turbine and a nozzle. The
compressor is powered by the turbine, which extracts energy from the expanding gas passing through
it. The engine converts internal energy in the fuel to kinetic energy in the exhaust, producing thrust.
All the air ingested by the inlet is passed through the compressor, combustor, and turbine, unlike the
turbofan engine described below.
TURBOFAN
A turbofan engine is a gas turbine engine that is very similar to a turbojet. Like a turbojet, it uses the
gas generator core (compressor, combustor, and turbine) to convert internal energy in fuel to kinetic
energy in the exhaust. Turbofans differ from turbojets in that they have an additional component, a
fan. Like the compressor, the fan is powered by the turbine section of the engine. Unlike the turbojet,
some of the flow accelerated by the fan bypasses the gas generator core of the engine and is
exhausted through a nozzle. The bypassed flow is at lower velocities, but a higher mass, making
thrust produced by the fan more efficient than thrust produced by the core. Turbofans are generally
more efficient than turbojets at subsonic speeds, but they have a larger frontal area which generates
more drag.

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TURBOPROP AND TURBO SHAFT
Turboprop engines are jet engine derivatives, still gas turbines that extract work from the hot-exhaust
jet to turn a rotating shaft, which is then used to produce thrust by some other means. While not
strictly jet engines in that they rely on an auxiliary mechanism to produce thrust, turboprops are very
similar to other turbine-based jet engines, and are often described as such.
Turbo shaft engines are very similar to turboprops, differing in that nearly all energy in the exhaust is
extracted to spin the rotating shaft, which is used to power machinery rather than a propeller, they
therefore generate little to no jet thrust and are often used to power helicopters.
PROPFAN
A propfan engine (also called "unducted fan", "open rotor", or "ultra-high bypass") is a jet engine
that uses its gas generator to power an exposed fan, similar to turboprop engines. Like turboprop
engines, propfans generate most of their thrust from the propeller and not the exhaust jet. The
primary difference between turboprop and propfan design is that the propeller blades on a propfan
are highly swept to allow them to operate at speeds around Mach 0.8, which is competitive with
modern commercial turbofans. These engines have the fuel efficiency advantages of turboprops with
the performance capability of commercial turbofans. While significant research and testing
(including flight testing) has been conducted on propfans, no propfan engines have entered
production.
RAMJET
Ramjets are the most basic type of ram powered jet engines. They consist of three sections; an inlet
to compress incoming air, a combustor to inject and combust fuel, and a nozzle to expel the hot gases
and produce thrust. Ramjets require a relatively high speed to efficiently compress the incoming air,
so ramjets cannot operate at a standstill and they are most efficient at supersonic speeds. A key trait

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of ramjet engines is that combustion is done at subsonic speeds. The supersonic incoming air is
dramatically slowed through the inlet, where it is then combusted at the much slower, subsonic,
speeds.
SCRAMJET
Scramjets are mechanically very similar to ramjets. Like a ramjet, they consist of an inlet, a
combustor, and a nozzle. The primary difference between ramjets and scramjets is that scramjets do
not slow the oncoming airflow to subsonic speeds for combustion, they use supersonic combustion
instead. The name "scramjet" comes from "supersonic combusting ramjet." Since scramjets use
supersonic combustion they can operate at speeds above Mach 6 where traditional ramjets are too
inefficient. Another difference between ramjets and scramjets comes from how each type of engine
compresses the oncoming airflow: while the inlet provides most of the compression for ramjets, the
high speeds at which scramjets operate allow them to take advantage of the compression generated
by shock waves, primarily oblique shocks

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TURBOFAN ENGINES
The turbofan or fanjet is a type of air breathing jet engine that finds wide use in aircraft propulsion.
The word "turbofan" is a portmanteau of "turbine" and "fan", the turbo portion refers to a gas turbine
engine which takes mechanical energy from combustion, and the fan, a ducted fan that uses the
mechanical energy from the gas turbine to accelerate air rearwards. Thus, whereas all the air taken in
by a turbojet passes through the turbine (through the combustion chamber), in a turbofan some of
that air bypasses the turbine. A turbofan thus can be thought of as a turbojet being used to drive a
ducted fan, with both of those contributing to the thrust. The ratio of the mass-flow of air bypassing
the engine core compared to the mass-flow of air passing through the core is referred to as the bypass
ratio. The engine produces thrust through a combination of these two portions working in concert;
engines that use more jet thrust relative to fan thrust are known as low bypass turbofans, conversely
those that have considerably more fan thrust than jet thrust are known as high bypass. Most
commercial aviation jet engines in use today are of the high-bypass type, and most modern military
fighter engines are low-bypass. Afterburners are not used on high-bypass turbofan engines but may
be used on either low-bypass turbofan or turbojet engines.
LOW BYPASS
HIGH BYPASS

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TWIN SPOOL TURBOFAN
Now, we can look at a little more of the bypass twin spool engine. This is as oppose to the earlier bypass
engine a twin spool engine, which means is now has two shaft spool of course, refers to the shaft. It is an
old terminology which people have used over the years and it refers to two shafts. Typically the two
shafts are concentric, there is an inner shaft which runs through and there is an outer shaft which
normally is used to drive the core engine, which comprises the one turbine which is the HP turbine, one
set of compressors which is referred to as the HP compressor. Hence, this spool is referred to as high
pressure spool or HP spool whereas, the inner concentric shaft which runs right through is run through
the low pressure turbine, which is a set of turbines quite often and which powers through the shaft this a
big fan and sometimes a small compressor over here. So, this produces a large amount of power and it is
often referred to as the low pressure spool.
This mechanical arrangement that people have a device essentially creates two mechanical arrangements:
one which is a low pressure arrangement, another which is a high pressure arrangement - two mechanical
arrangements. Now, this allows us essentially to run the two spools at two different rotating speeds or
rpm.
As a result of which most of the engines today, the HP spool runs at a higher rpm and the LP spool runs
at much lower rpm; the reason for which we shall come to know as we go along. As a result of this
independence of the two spools, the designer now has the flexibility to design the two spools in a manner
such that they independently operate at their best and most efficient operating condition. One can well
imagine and as we will go more and more, you would probably become familiar with these components
and you would realize this independence space very important for operating each of them at their best
efficient operating conditions.
There are a few other components that are very important for the efficient operation of a jet engine. The
first thing is, as I mentioned earlier, every such jet engine has an intake. Now, this is the intake that all jet
engines would have and flow comes in through with hence it is called an intake. Now, design of this
intake is very intricate affair, it is not simple and this shape of the intake over here often referred to as
cowling is very important for the aerodynamic efficiency of the operation of this jet engine, when it is
flying with an aircraft. In a high speed aircraft the design of this cowling appears in a very important
issue, it appears in the design right in the beginning and it is a very long drawn out air. The entire outer
surface of the engine needs to be appropriately designed. As you remember, quite often, in many of this
aircraft that you may have seen this engine is seen to be hanging outside the aircraft quite often hanging

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from the wings and this entire outer surface is opened to the air that is flowing. So, certain amount of air
is coming in and that is going through the propulsive device to give you a jet which creates a thrust.
There is a certain amount of air that is going outside flowing over the surface and this air actually
produces drag that is additive to the drag of the aircraft itself. Remember, the thrust that is produced by
this engine would have to overcome this drag for the aircraft to fly. Now, the engine designer has a job to
make sure that the engine itself does not produce a large amount of drag. Hence, the outer shape over
here and quite specifically over here is often referred to as boat tail shape and this ensures that the
external flow over this propulsive device does not produce large amount of drag, which as you know
would have to be overcome by the thrust produced by this itself. Towards the exit of this propulsive
device as we have seen, we have a cold bypass flow in this bypass engine and we have a hot inner flow or
a core flow and then there is a mixing over here. This mixing needs to be done very uniformly, so that the
jet that comes out has a uniform temperate and pressure at the exit phase.
Now, this is very important and hence the design of this nozzle system over here, all the way from here,
the shaping over here is extremely important in terms of aerodynamics and the gas dynamic because at
the exit phase right over here, we want absolutely uniform temperature and pressure profile because if the
pressure profile is not uniform remember, the thrust that is produced is not going to be a linear or thrust
in the direction of the jet, but it will be a thrust produced which will have all kinds of components
sidewise or upwards or downwards components, which will render the aircraft movement in the flight in
various kinds of directions . As a result, the aircraft will tend to have motions, which could be a pitching
motion, which could be a yawing motion because the jet that is coming out here is not uniform and is not
producing thrust that is a unidirectional but, producing multi directional thrust. So, the flow here needs to
be extremely uniform as it is going out and hence the design of these components here is of great
importance.

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ADOUR MK 871 ENGINE
The Rolls-Royce Turbomeca Adour is manufactured by Rolls-Royce in collaboration with
Turbomeca. The engine was originally developed to power the SEPECAT Jaguar, an Anglo-French
jet ground-attack aircraft. The Adour is a two-spool turbofan engine available in both afterburning
and non-afterburning variants.
The Mk871 (U.S. designation F405-RR-401) Adour powers both ground-attack and advanced trainer
aircraft, including the SEPECAT Jaguar, Mitsubishi T-2 and F-1 aircraft, BAE Systems Hawk, and
the Boeing T-45 Goshawk. The Adour is a rugged and easy-to-maintain engine, which has earned its
reputation as a proven and dependable power plant for ground attack and advanced trainer aircraft.
The Adour Mk951 (U.S. designation F405-RR-402) is the newest version of the non-afterburning
range of Adour engines. It powers the BAE Systems Hawk and the T-45 Goshawk military trainer
aircraft.

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The Adour engine is a twin shaft turbofan engine with medium bypass and pressure ratio. It operates
at moderate temperature and rotational speeds. There are a total of seven stages of compressors, two
LP and five HP compressors. Neither compressor is fitted with inlet guide vanes. The compressors
are driven by separate shafts which rotate in CCW direction. Both shafts are supported by bearings
at front and back. A forward extension of HP shaft is supported at the rear by ball and roller bearing
which carries a bevel gear to drive external HSG via a quill shaft. Area around bevel gear is known
as internal gear box.
The HSG drives LP fuel pump, HP fuel pump, DC generator, HP shaft tachometer generator, starter
motor, oil pumps and Hydraulic pumps. To ensure stability during engine starting a bleed valve is
fitted to pass air from HP compressor outlet to bypass duct.
A self-contained oil system is fitted for lubrication and cooling gears and bearings and the oil system
is of full flow re-circulatory type. Engine is controlled by a single cockpit lever which operates via a
Cambox, both the throttle and fuel shut-off valve on the FCU. To control the fuel during starting a
separate sub idle FCU is used.
ENGINE OPERATION
The engine operates by including air which is first compressed in LPC and then divides in to 2
streams, one stream flows through bypass duct whilst, the other is further compressed by HPC and
then flows into combustion chamber where it is heated by adding and burning fuel. The resultant
expansion of gases forces it rearwards through HPT and LPT which extracts sufficient energy to
drive compressor and accessories.
After leaving turbine, hot gases are mixed with the cooler bypass air and flows through exhaust
collector to the propelling nozzles. As the thrust developed by the engine is a function of air mass
flow and turbine entry temperature. The power output can be controlled by regulating amount of fuel
flow into combustion chamber.
LEADING PARTICULARS
Type of Engine: Turbofan
Arrangement: twin spool axial flow, Bypass ratio 0.75:1
Nominal length: 1997mm
Nominal diameter: 1036mm
Weight: 639.6 Kg
COMPRESSOR MAX. RATING
LPC:
- 2 stage axial flow
- Pr. Ratio 2.5:1
- Max rotational speed 108%
HPC:
- 5 stage axial flow
- Pr. Ratio 4.4:1
- Max rotational speed 104%

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COMBUSTION SYSTEM
Type: annular
Burners: 18 air/fuel spray nozzles
Igniters: 2 High energy plugs
TURBINE SYSTEM
HPT:
- Axial flow
- One stage
- NGV and turbine blades air cooled
LPT:
- Axial flow
- One stage
- NGV and blades air cooled
STARTING SYSTEMS
The starting system is used to start Adour engine on the ground or a cold assisted relight in flight. It
provides rotation of HPC shaft in order to induce an adequate supply of air for combustion; the
system can be sued for dry cranking the engine during service.
It consists of an air frame mounted gas turbine air producer connected to an engine mounted air
starter motor by duct. The air generated by the turbo is directed to a starter motor via a start valve or
vented overboard by dump valve according to signals received from electronic start control unit.
The start control unit sequences the start cycle, following cockpit selection and will terminate if any
malfunction occurs. During main engine starting fuel is supplied to spray nozzles from SIFCU and
FCU. Ignition to 2 igniter plugs via the ECA provided correct LPC shaft rotation is confirmed.
ADOUR MK 871 MODULES
The Adour MK 871 engine is divided into 11 modules each performing a distinct function in the
engine. The division into modules has been carried out for ease of assembly. The various modules
are:
Module 1: LP Compressor-Stage 1
It comprises of a low pressure compressor with a rotor (27 blades), a stator (23 blades) and a rotor
again (32 blades).
Module 2: LP Compressor-Stage 2
The stage 2 of LP compressor comprises of only 2 stators.

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Module 3: Intermediate casing
The compressor intermediate casing houses the stage 2 LP compressor and the internal gearbox. The
internal gearbox consists of a bevel gear mounted in ball thrust and roller bearing assembly. It
provides drive for the splined HP Compressor rotor shaft. It is driven by the High speed gear box.
Module 4: HP Compressor
The HP Compressor consists of two main assemblies, the HP rotor and HP compressor case and
vanes. The rotor consists of 5 stages of rotor blades secured to a drum, case and vanes. Stator
consists of 4 stages built up around the compressor rotor stages.
Module 5: HP NGV
HP NGV refers to high pressure nozzle guide vanes. These vanes help in streamlining of the high
pressure, turbulent air exiting from the HP compressor. This helps in preventing damage to the HP
turbine caused due to turbulent air.
Module 6: HP Turbine
The HP turbine uses the High Pressure air from the compressor to drive the HP shaft.
Module 7: LP NGV
The LP NGV has a similar function to HP NGV. It removes any turbulence in the air exiting from
HP turbine.
Module 8: LP Turbine
The LP turbine uses the energy of the LP air to drive the LP shaft
Module 9: Exhaust Mixer Section
The exhaust mixer section has two parts the annular exhaust mixture and the exhaust cone. The
exhaust mixer section mixes the cold bypass air with air coming through the compressors/turbine.
Module 10: HS Gearbox
The high speed gearbox is mounted outside the intermediate casing. It comprises of 32 gears and 28
bearings. The HSG is coupled to the internal gearbox and micro-turbo. It draws power from the
micro-turbo and transmits it to the internal gearbox which in turn drives the HP rotor Shaft.
Module 11: Accessories Pack
The accessories pack mainly has to do with the Fuel and oil. It consists of Fuel and oil filters. It also
consists of a low pressure fuel pump, high pressure fuel pump and an oil pump. The fuel control unit
and Cambox are also present here. The pack also has a fuel cooled oil cooler.
Apart from the 11 modules, the engine also has a Micro turbo which is used to start the engine and
the combustion section.
The combustion section does not have any designated module. Major components are the
combustion liner, front inner combustion case and combustion outer case. The combustion liner is
circular in shape and is built up in section welded together to form 2 skins, the area between the 2
skins being the combustion area. The unit tapers towards the front and forms slots, each slot being
lined with fuel supply nozzles. There are 18 nozzles present.

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The Bypass section in the engine splits the air from the LP compressor into 2 main flows in the
compressor intermediate casing. Approximately 50% of the airflow is directed into the high pressure
compressor and the remaining flow passes through the annular bypass duct area to the exhaust
mixture. The front Bypass duct has liners riveted to soleplates which is used for fuel tank
pressurization, fuel spray nozzle feed and air bleed valve. The rear Bypass duct similarly is used for
oil return and vent, feed oil to bearings, fuel drain and oil tank support.
Air pressures in the Adour engine are used as follows; P2 is used for fuel tank pressurization, HSG
air blown seal, anti-icing and cabin air. P3 is used for cooling of HP NGV, HP Turbine (front). P3
intermediate is used for cooling LP NGV, HP turbine rear and LP turbine cooling.
The major materials used are Titanium, Magnesium, nimonic, steel alloys and Sermetal. The
combustion chamber is coated with thermal barrier coating. Thermoseal coating are also provided to
certain part made of Sermetal.
ASSEMBLY OF ADOUR MK871
The Adour MK871 engine is assembled using components fabricated in several auxiliary machine
shops present within the Engine division. The components for the engine are ordered by the Adour
Mk871 overhaul and assembly division. Once the Assembly division receives the components, the
various parts are segregated module wise and placed on tables allocated to each module. Each
module is assembled individually by different Deputy Managers. The Dy. Managers are assisted by
apprentices. The assembled modules are tested for various parameters such as balancing of rotating
masses and fuel flow rate. These are then sent for final assembly, which is carried out in separate
section of the division. Once the final assembly is completed, the engine is sent to the test bed for
thorough testing and inspection. The assembly of modules is carried out by hand using various tools
such as spanners, wrenches, screw drivers, etc. The entire shop floor is air conditioned to ensure a
clean environment for assembly.

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BALANCING OF ROTATING MASSES
Why Balance? Rotating components experience significant quality and performance improvements
when balanced. Balancing is the process of aligning a principal inertia axis with the geometric axis
of rotation through the addition or removal of material. By doing so, the centrifugal forces are
reduced, minimizing vibration, noise and associated wear. Virtually all rotating components
experience significant improvements when balanced.
Consumers throughout the global market continue to demand value in the products they purchase.
They demand performance - smaller, lighter, more efficient, more powerful, quieter, smoother
running and longer lasting. Balancing can contribute to each of these and is one of the most cost
effective means of providing value to the consumer.
TYPES OF UNBALANCE
The location of the mass center and the principal inertia axes are determined by the distribution of
mass within the part. Unbalance exists when the axis of rotation is not coincident with a principal
inertia axis. It is important to draw a distinction between unbalance and balance correction.
Unbalance is a mass property. It becomes a characteristic of the part when an axis of rotation is
defined. Balance correction is a means to alter the mass properties to improve the alignment of the
axis of rotation with the mass center and/or the central principal axis. Both can be expressed as
weights and radii and have shared terminology.
STATIC UNBALANCE:
A condition of static unbalance exists when the mass center does not lie on the axis of rotation. Static
unbalance is also known as Force Unbalance. As defined, static unbalance is an ideal condition, it
has the additional condition that the axis of rotation be parallel to the central principal axis & no
couple unbalance.
Static unbalance has the units of weight·length or mass·length and is expressed as;
U = w·r or U = m·r
Where w is weight (or m is mass) and r is the effective radius of the weight. Common units of static
unbalance are in·oz or g·mm.
Another convenient expression of static unbalance is the total weight of the workpiece, w, times the
distance between the mass center and the axis of rotation, e. U = w·e
As discussed earlier, a workpiece is in static balance when the mass center lies on the axis of
rotation. When this condition exists, the part can spin on the axis with no inertial forces; that is to say
without generating centrifugal force. Even parts intended for static applications, such as speedometer
pointers or analog meter movements, benefit from being in static balance in that the force of gravity
will not create a moment greater at one angle than at another which causes them to be non-linear.
Static unbalance can be corrected with a single weight. Ideally the correction is made in the plane of
the mass center and is sufficient to shift the mass center onto the axis of rotation. It is important to
align the correction with the initial unbalance to move the mass center directly towards the axis of
rotation. Static unbalance can be detected on rotating or non-rotating balancers.

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COUPLE UNBALANCE:
If a specific condition that exists when the central principal axis of inertia is not parallel with the axis
of rotation. Couple unbalance is often presented as dynamic unbalance in engineering classes;
however this term is defined otherwise by ISO 1925 and is reserved for the more general case of
combined static and couple unbalance. As defined, couple unbalance is an ideal condition. It carries
the additional condition that the mass center lies on the axis of rotation & no static unbalance.
Couple unbalance has the units of weight·length2 or mass·length2 and is expressed as;
U = w·r·d or U = m·r·d
Where w is a weight (or m is mass), r is the effective radius of the weight and d is the couple arm.
Units for couple unbalance are oz·in2 or g·mm2.
Couple unbalance appears as the off-diagonal terms in the inertia matrix for a rigid body. This is an
indication that the inertial axes are not aligned with the principal axes. It can be expressed as a vector
with direction perpendicular to the plane of the radius vector and the couple arm vector. This is the
axis about which the couple acts and is 900 or normal to the plane in which balance correction
should be made.
Couple correction requires that two equal weights be added to the workpiece 180° apart in two
correction planes. The distance between these planes is called the couple arm. The location of the
correction planes is arbitrary provided the product of w·r·d matches the unbalance. Whereas static
unbalance can be measured with a non-rotating balancer, couple unbalance can only be measured on
a rotating balancer.
DYNAMIC UNBALANCE
The most general case of unbalance is that in which the central principal axis is not parallel to and
does not intersect the axis of rotation. Dynamic unbalance is also referred to as two plane unbalance,
indicating that correction is required in two planes to fully eliminate dynamic unbalance. A two
plane balance specification is normally expressed in terms of w·r per plane and must include the
axial location of the correction planes to be complete. Dynamic unbalance captures all the unbalance
which exists in a rotor. This type of unbalance can only be measured on a rotating balancer since it
includes couple unbalance. Since dynamic unbalance is a combination of static and couple unbalance
and since static and couple unbalance have different units, there are no unique units for dynamic
unbalance. It can be expressed as static and couple or in terms of the balance corrections required.
QUASI-STATIC UNBALANCE
A special form of dynamic unbalance in which the static and couple unbalance vectors lie in the
same plane. The central principal axis intersects the axis of rotation, but the mass center does not lie
on the axis of rotation. This is the case where an otherwise balanced rotor is altered (weight added or
removed) in a plane some distance from the mass center. The alteration creates a static unbalance as
well as a couple unbalance. Conversely, a rotor with quasi-static unbalance can be balanced with a
single correction of the right magnitude in the appropriate plane.

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BALANCE CORRECTION
Up to this point, unbalance has been discussed primarily as a mass property and the mass distribution
about the axis of rotation. This section discusses methods of correcting unbalance. These correction
methods are recipes for re-distributing a rotor mass so as to better align the central principle inertia
axis with the axis of rotation. The two most common methods employed for rigid rotors are Right-
Left and Force-Couple. A balance computer will normally display balance corrections in one or
both of these methods. When calculated correctly, both methods will have identical effects on a rigid
rotor.
Any condition of unbalance can be corrected by applying or removing weight at a particular radius
and angle. The magnitude of a balance correction is correctly stated in terms of a weight, w, at a
radius, r. The product of weight and radius are unbalance, U. U = w·r
The strategic addition or removal of weight redistributes the mass, altering the mass properties to
better align the mass center and the central principal axis with the axis of rotation.

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AUTOMATING DYNAMIC BALANCING FOR ADOUR MK871
ENGINE
Dynamic Balancing for Adour MK871 engine is carried out for modules 01, 04, 06, 08 and the stub
shaft. The dynamic balancing is carried out on a Horizontal Balancing machine. The basic procedure
is to place the modules on the rollers and rotate it at around 650 rpm, any unbalance is picked by
sensors at the bearings, and this unbalance is shown in the monitor. This unbalance needs to be
balanced out by the technician by the method of trial and error with some standard weights as shown
in the table.
Sl.
No.
Module
No.
Plane
No.
Std. Weights No. of Slots Tolerance
1. 01 01 Bolt: AS44702, Washer: AS44691
Weight big: 0260123610
Weight small: 0260123600
15 15gcm
02 Bolt: AS44702, Washer: AS44691
Weight big: 0260123510
Weight medium: 0260123300
Weight small: 0260123290
32 15gcm
2. Stub Shaft - Bolt: BLT7110, Weights: AX66847,
AX68696
AX68698, AX68700
20 5gcm
3. 04 01 Bolt: AS20908, Nut: AS20624,
Washer: 0260200430
24 3.6gcm
02 Bolt: 0260203840, Nut: AS20624
Washer: 0260200430
15 3.6gcm
4. 06 - Bolt: BLT7019, Nut: AS20624
Washer: AS20430
12 30gcm
5. 08 - Nut: AS20626, Washer: SP123G 15 3.6gcm
The need for automation of the balancing process arises due to the fact that the trial and error method
to determine the std. weights required to balance the modules is time consuming and taxing on the
technician. Hence it is necessary to create a program to automate this process by using a C/C++
program. The program will ask the user for required module and plane. After this the user needs to
enter the std. weights and the unbalance values shown by the machine. This program will then
display the combination of weights that would reduce the unbalance to less than the tolerance. This is
useful as it would reduce time and effort.

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C PROGRAMMING LANGUAGE
C is a general-purpose, imperative computer programming language. It supports structured
programming, lexical variable scope and recursion, while a static type system prevents many
unintended operations. By design, C provides constructs that map efficiently to typical machine
instructions, and therefore it has found lasting use in applications that had formerly been coded in
assembly language, including operating systems, as well as various application software for
computers ranging from supercomputers to embedded systems.
C was originally developed by Dennis Ritchie between 1969 and 1973 at AT&T Bell Labs, and used
to (re-)implement the Unix operating system. It has since become one of the most widely used
programming languages of all time, with C compilers from various vendors available for the
majority of existing computer architectures and operating systems. C has been standardized by the
American National Standards Institute (ANSI) since 1989 (see ANSI C) and subsequently by the
International Organization for Standardization (ISO).

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ALGORITHM OF C/C++ PROGRAM FOR AUTOMATION OF
DYNAMIC BALANCING
Step 1: Display Module choices and read user module choice.
Step 2: If module choice is 01 or 04 read user’s choice of plane.
Step 3: Assign number of holes, tolerance and number of std. weights depending on choice of
module and plane.
Step 4: Read value of std. weights for the module and plane of choice.
Step 5: Read value of unbalance and unbalance angle as show in balancing machine.
Step 6: Convert angle to radians by multiplying with pi/180.
Step 7: Divide 360 by number of holes to get increment in angle for each hole.
Step 8: If module choice is not stub shaft then do steps 9-13, otherwise go to step 14.
Step 9: loops are started to choose combinations of 1, 2, 3 and 4 std. weights at all the combination
of angles/slots, but loops with 2 or more weights at same angles need to be skipped.
Step 10: Calculate the sum of m.r.sin(angle) and m.r.cos(angle), hence find the resultant of the two
sums.
Step 11: If the resultant is less than tolerance then store it as minimum and store the values of
weights and the hole positions.
Step 12: The least value of tolerance is displayed along with the values and positions of weights for
the combinations of 1, 2, 3 and 4 weights.
Step 13: the user is asked at the end of calculation for each combination if the user wants to exit.
Step 14: If the choice is stub shaft then do the following steps.
Step 15: Steps 9-13 need to be repeated, however loops with angles at 0, 120 and 360 need to be
skipped.
Step 16: end.

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VERIFICATION OF THE C/C++ PROGRAM
The Verification of the program was carried out on module 04, the initial unbalance is as shown in
the figure below:
Given the unbalance in the two planes of module 04, the program was run as shown below:
Plane 1:

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Plane 2:

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The given solution for unbalance was implemented by fixing the required weights at the given angles
and on the required plane. The resultant unbalance in module after attaching the weights is as shown
below:

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CONCLUSION
By using the program, the resulting unbalance is within the tolerance prescribed by the company as
seen in the computer generated graphs. Therefore, the process of calculating the location and weight
of balancing weights has been automated through the program. This has reduced the time taken to
balance a module by about 20 to 30%.

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REFERENCES
 wikipedia.org
 hal-india.com
 The training manual of The Adour MK871 engine given by Rolls Royce
 The Basics Of Balancing by Gary K. Grim, John W. Haidler, Bruce J. Mitchell, Jr.
 Static and Dynamic Balancing of Rigid Rotors by Brul & Kjaer.
 Dynamic Balancing Of Rotating Machinery Experiment By Dr. K. Nisbett
 Jet Engine Basics: propulsion by Boeing
 Process Description: How a Turbofan Engine Works By Colin Kling
 Introduction to Aerospace Propulsion By Prof. Bhaskar Roy, Prof. A. M. Pradeep
Department of Aerospace Engineering , Indian Institute of Technology, Bombay Lecture #03
& #33