A SUMMER TRAINING REPORT On “Summer Internship” Completed at
HINDUSTAN AERONAUTICS LIMITED HELICOPTRER DIVISION BENGALURU, KARNATAKA
Submitted in partial fulfilment of the requirement r equirement For the award of the Degree of Bachelor of Technology In Aeronautical Engineering UNIVERSITY COLLEGE OF ENGINEERING, RTU, KOTA
Submitted By:
Mayank Gupta (15/788) Vaibhav Trivedi (14/618) Mohammed Farman (14/605) B.Tech Final Year
Certificate
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III
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Acknowledgement The completion of any work is a joint endeavour of all the individuals that support, inculcate and foster the much needed enthusiasm and confidence to the door of the work, without which the whole task may prove to be an impossible mission. At the very outlet, we convey our sincere gratitude to all people in HAL Helicopter Division for their co-operation during my industrial training period of one month. Towards the successful completion of the training, we would like to acknowledge our debt to our advisors. The training work would not have been possible without their support, encouragement and constructive comments we received from them. We also t hank our coordinator Mr. Khan for his support and guidance.
Mayank Gupta/ Vaibhav Trivedi/ Mohammed Farman Bachelor of Technology Aeronautical Engineering
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Preface Practical Training, which has to be carried out outside the university, is part of the curri culum. For us, this was a great opportunity to go Bangalore, apply our knowledge in a practical environment and to increase our competences. Our assignment was to detail study the various operations followed for manufacturing a Helicopter. In the first few days it was not really clear in what direction we wanted to go and which results we wanted to obtain, but during the process this became clearer. Mr G. H. Raju , our supervisor at the Hindustan Aeronautics Limited, guided us very well in this, what contributed to results we have obtained. Looking back from my training, we can say that it has been a valuable and truly amazing experience. The working environment and the people at the Centre for Design are really great, which makes all the difference. We learned a lot during our internship and also the experience of living in a big city like Bangalore will remain fore ver.
Mayank Gupta/ Vaibhav Trivedi/ Mohammed Farman Bachelor of Technology Aeronautical Engineering
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Table of Contents Certificate ______________________ __________________________________ _______________________ ______________________ ______________________ ___________ II Acknowledgement ______________________ __________________________________ _______________________ ______________________ _______________ ____ V Preface_________________________ Preface______________ _______________________ _______________________ ______________________ _____________________ __________ VI Table of Contents _____________________ _________________________________ _______________________ ______________________ ________________ _____ VII Table of Figures ______________________ __________________________________ _______________________ ______________________ ________________ _____ IX 1 - INTRODUCTION _____________________ ________________________________ ______________________ ______________________ _______________ ____ 1 1.1 About HAL __________________________ _____________ _________________________ __________________________ _______________________ _________ 1 1.2 History ______________ _________________________ _______________________ _______________________ ______________________ _________________ ______ 2 2. ALH TRAINING _____________________ _________________________________ _______________________ ______________________ _______________ ____ 4 2.1 Role of Helicopters _____________________________ ________________________________________ ______________________ _______________ ____ 4 2.2 Advanced Light Helicopter (ALH- DHRUV)______________________ _________________________________ _____________ __ 4 2.3 Features of ALH ______________________ _________________________________ ______________________ ______________________ _____________ __ 4 2.4 Role of ALH Training _____________________ ________________________________ ______________________ _____________________ __________ 4 2.5 Customers ______________________ __________________________________ _______________________ ______________________ _________________ ______ 4 2.6 ALH Training Classification Classific ation ______________________ _________________________________ ______________________ _______________ ____ 4 3. MACHINE SHOP_____________________ _________________________________ _______________________ ______________________ _______________ ____ 6 3.1 Operations in Machine Shop ______________________ _________________________________ ______________________ _______________ ____ 6 3.2 Turning ________________________________________________________________ 6 3.3 Grinding _______________________________________________________________ 6 3.4 Taper Turning _____________________ _________________________________ _______________________ ______________________ _______________ ____ 7 3.5 Gear Cutting ______________________ __________________________________ _______________________ ______________________ _______________ ____ 7 3.6 Milling ______________ _________________________ _______________________ _______________________ ______________________ _________________ ______ 7 3.7 Drilling _____________________ ________________________________ ______________________ ______________________ _____________________ __________ 7 3.8 Boring __________________________ ____________ __________________________ _________________________ __________________________ ______________ _ 7 4 - METHODS AND TOOLING _____________________ _________________________________ _______________________ ________________ _____ 8 4.1 Methods ___________________________ ______________ _________________________ _________________________ _________________________ ____________ 8 4.2 Tooling ________________________________________________________________ 8 4.2.1 Tooling planning____________________ planning_______________________________ _______________________ _______________________ ___________ 9 4.2.2 Tool design ___________________________ ______________ __________________________ __________________________ __________________ _____ 9 5. HEAT TREATMENT SHOP _________________________ ____________ __________________________ ________________________ ___________ 10 5.1 Heat Treatment _____________________ ________________________________ ______________________ ______________________ ______________ ___ 10 5.2 Heat treatment techniques ____________________ _______________________________ _______________________ __________________ ______ 10 5.3 Furnace Types __________________ _____________________________ ______________________ ______________________ __________________ _______ 10 6. PROCESS SHOP ________________________________ ____________________ _________________________ __________________________ _____________ 13 VII
6.1 Surface finishing processes ___________________ ______________________________ _______________________ __________________ ______ 13 6.2 Choosing a Metal Finishing Process ____________ _______________________ _______________________ __________________ ______ 14 7. WELDING & SHEET SHEET METAL SHOP _____________________ _________________________________ ____________________ ________ 15 7.1 Welding Weldi ng ___________________________ ______________ _________________________ _________________________ ________________________ ___________ 15 7.1.1 Types of welding welding _____________________ ________________________________ ______________________ ____________________ _________ 15 7.2 Sheet Metal Me tal _____________________ _________________________________ _______________________ ______________________ ________________ _____ 17 8. BLADE SHOP ______________________________ _________________ __________________________ __________________________ _________________ ____ 18 8.1 Procedure for Blade Manufacturing _____________________________ ________________________________________ ____________ _ 18 8.2 Servicing ______________________ _________________________________ ______________________ ______________________ __________________ _______ 19 9 - STRUCTRAL ASSEMBLY ________________________ ___________________________________ ______________________ ______________ ___ 20 9.1 Types of Helicopter Construction _____________________ _________________________________ ______________________ __________ 20 9.1.1 Tubular Construction ______________________ __________________________________ _______________________ _______________ ____ 20 9.1.2 Stressed Skin Construction ______________________ _________________________________ ______________________ ____________ _ 20 9.1.3 Bonded construction:construction:- _____________________ _________________________________ _______________________ _________________ ______ 21 9.2 Different sections of helicopter helicopter structure _____________________ _________________________________ ________________ ____ 21 10. TRANSMISSION ASSEMBLY _____________________ ________________________________ ______________________ ______________ ___ 23 10.1 Main Rotor Transmission _____________________ _________________________________ _______________________ _______________ ____ 23 10.2 Tail Rotor Drive System __________________________ _____________________________________ ______________________ ____________ _ 24 10.3 Clutch _______________________________________________________________ 24 10.4 Freewheeling Unit _____________________ _________________________________ _______________________ _____________________ __________ 25 11. QUALITY & PROGRAMME ENGINEERING ENGINEERING _____________________ ________________________________ ____________ _ 26 11.1 Quality Qualit y ___________________________ ______________ _________________________ _________________________ ________________________ ___________ 26 11.2 Programme Engineering ______________________ __________________________________ _______________________ _______________ ____ 26 12. DLE _________________________ ____________ __________________________ __________________________ __________________________ _________________ ____ 27 13. FINAL ASSEMBLY __________________________ _____________ __________________________ __________________________ _______________ __ 28 13.1 Electrical System ______________________ __________________________________ _______________________ _____________________ __________ 28 13.2 Avionics ______________________ __________________________________ _______________________ ______________________ ________________ _____ 28 13.3 AFCS (automatic flight control system) s ystem) ________________ ___________________________ _____________________ __________ 29 13.4 MSI (mission s ystem integration) _________________ ____________________________ ______________________ ______________ ___ 29 13.5 WSI (weapon system integration) i ntegration) ______________________ __________________________________ ____________________ ________ 29 14. CIVIL HELICOPTERS _____________________ ________________________________ ______________________ ____________________ _________ 30 BIBLIOGRAPHY ________________ ___________________________ _______________________ _______________________ _____________________ __________ 32
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Table of Figures Figure 1: HAL corporate ........................................... .................................................................. ............................................. ............................................. ......................... 1 Figure 2: Process chart of Method Department Department .......................................... ................................................................. ................................... ............ 8 Figure 3: Box-type furnace ............................................ .................................................................. ............................................ ......................................... ................... 11 Figure 4: Pit Furnace ......................................... ............................................................... ............................................ ............................................. .............................. ....... 11 11 Figure 5: Salt-bath furnace ........................................... ................................................................. ............................................ ......................................... ................... 11 Figure 6: Vacuum furnaces ........................................... ................................................................. ............................................ ......................................... ................... 12 Figure 7: Muffle furnace............................................ ................................................................... ............................................. ............................................ ...................... 12 Figure 8: Electric Arc Welding.......................................... Welding................................................................. ............................................. .................................... .............. 15 Figure 9: Welding symbols ............................................ .................................................................. ............................................ ......................................... ................... 15 Figure 10: Gas Welding............................... Welding..................................................... ............................................ ............................................. ..................................... .............. 16 Figure 11: T.I.G. Welding............................ Welding.................................................. ............................................ ............................................ ..................................... ............... 16 Figure 12: 12: Spot Welding Welding Process ........................................... .................................................................. ............................................. ................................ .......... 17 Figure 13: 13: Spot Welding Welding Machine ............................................ ................................................................... ............................................. ............................. ....... 17 Figure 14: Bending Machine Machine ......................................... ............................................................... ............................................ ......................................... ................... 17 Figure 15: Punching Machine Machine ........................................... ................................................................. ............................................ ..................................... ............... 17 Figure 16: Cross Section of typical Blade ........................................... .................................................................. ......................................... .................. 18 Figure 17: Cross Section of Cheetah Blade Blade ..................................... ........................................................... ............................................ ...................... 19 Figure 18: Truss type design ......................................... ............................................................... ............................................ ......................................... ................... 20 Figure 19: Semi-monocouque Semi-monocouque ............................................ .................................................................. ............................................ ..................................... ............... 20 Figure 20: Monocouque Monocouque ..................................... ........................................................... ............................................ ............................................. .............................. ....... 21 21 Figure 21: Helicopter structural parts ............................................. .................................................................... ............................................ ..................... 21 Figure 22: Tail Boom Section............................................ .................................................................. ............................................ ..................................... ............... 22 Figure 23: Helicopter Parts........................................ Parts.............................................................. ............................................ ............................................ ...................... 23 Figure 24: Main rotor system ............................................ .................................................................. ............................................ ..................................... ............... 24 Figure 25: Tail Rotor Drive System................................... System......................................................... ............................................. ..................................... .............. 24
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1 - INTRODUCTION 1.1 About HAL The aerospace industry ranks top among the world’s largest manufacturing industries in terms of people employed and value of output. The aerospace industry is one of the defining industries of this century. centur y. Aerospace manufacturing is a high-technology industry that produces aircraft, guided missiles, space vehicles, aircraft airc raft engines. Also included among its concerns are major flight-vehicle subsystems such as propulsion and avionics (aviation e lectronics) and key support systems necessary for the testing, operation, and maintenance of fli ght vehicles. The Indian Aerospace Industry is witnessing an unprecedented growth. Hindustan Aeronautics Limited (HAL), which is fully owned by the Government of India, is the premier aerospace company in the country. HAL has played a major role in the Defence aviation of India through design, manufacture and overhaul of fighters, trainers, helicopters, transport aircraft, engines, avionics and system s ystem equipment. HAL is now ranked 34th in the list of world’s top 100 defence companies. HAL is one of the largest aerospace companies in Asia, HAL has annual turnover of over USD 2 billion. More than 40% of HAL's revenues come from international deals to manufacture aircraft engines, spare parts, and other aircraft materials. HAL, a Defence PSU, is a major player in the global aviation arena. It has built up comprehensive skills in design, manufacture and overhaul of fighters, trainers, helicopters, transport aircraft, engines, avionics, system equipment and as well as operating airports. HAL was conferred NAVRATNA status by the Government of India on 22nd June 2007. HAL has won several International & National Awards for achievements in R&D, Technology, Managerial Performance, Exports, Energy Conservation, Quality and fulfilment of Social Responsibilities. HAL has 20 production divisions for manufacture and overhaul of aircraft, helicopters, engine and accessories. 10 co-located R&D Canter’s Canter’s to give a thrust to research & development. Which again are divided into various complexes. Each complex is headed by a Managing Director (MD).
HAL Corporate
BENGALURU
MiG
HELICOPTER
ACCESSORIES
DESIGN
COMPLEX
COMPLEX
COMPLEX
COMPLEX
COMPLEX
Figure 1: HAL corporate
HAL has its five complex (refer figure 1) and several divisions in Bengaluru, Nasik , Hyderabad, Kasargod , Lucknow, Kanpur, Korwa, Barrackpore , Koraput and Liaison,
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and offices in Delhi, Chennai, and Visakhapatnam. HAL Nasik and HAL Koraput come under MiG Complex. HAL’s major supplies/services are to Indian Air Force, Indian Navy, Indian Army, Coast Guard and Border Security Force. Transport aircraft and Helicopters have been supplied to Airlines as well as State Governments. The Company has also achieved a foothold in export in more than 20 countries, having demonstrated its quality and price competitiveness. HAL is a major partner for the Space Vehicle Vehicl e programmes of the Indian Space Research Rese arch Organization. It has also diversified into the fields of industrial & marine gas turbine business and real-time software business.
1.2 History With the objective of promoting aviation industry for assembly and overhaul of aircraft, engines and accessories under license, Hindustan Aircraft Factory was setup by the late Walchand Hirachand on 24th December 1940. The Government of India became a shareholder in March 1941 and took over the t he Management in 1942. Helicopter Division was established in July 1970. The division manufactures single engine as well as twin engine helicopters to cater the growing needs of the market. Helicopter Division manufactures Rudra, Dhruv, Cheetah, Chetak, Cheetal, Lancer, LUH & LCH helicopters. The division is supported by the co-located R&D center – Rotary Rotary Wing Research & Design Centre (RWR&DC). The MRO division caters to the Maintenance, Repair Repair & Overhaul activities of helicopters. helicopters. The Rotary Wing Academy focuses on training of pilots. HAL started manufacturing of helicopters in 1962, by entering an agreement with M/s SUDAVIATION (Presently M/s EUROCOPTER, France) for production of Aloutte III helicopters. (Chetak). The first Chetak (Aloutte III) in ‘Fly Away’ condition delivered in 1965. License agreement for production of Cheetah (LAMA SA 315-B) signed with M/s SNIAS (presently M/s, Eurocopter) in 1970. First Cheetah manufactured from raw materials was delivered in 1976-77. In 1990s, HAL has developed a light attack helicopter “Lancer”. The basic struct ure of the lancer is derived from reliable and proven Cheetah helicopter. The helicopter has bullet proof front panels. Gun cum Rocket pod one each (70 mm Rocket+12.5 mm Gun) fitted on either side. An optical sight has been fitted for accurate firing. The Cheetal helicopter is a re-engined variant of Cheetah helicopter. The Cheetal helicopter set the world record of world’s highest landing at ‘Saser Kangri’ of Himalayas in 2006. HAL Helicopter division has successfully manufactured 600 Single Engine helicopters. HAL achieved self-reliance in design, developing & manufacturing of twin engine Advanced Light Helicopter “Dhruv”. Dhruv is a multi-role, multi-role, multi mission all weather helicopter in the 5.5 ton
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category. The indigenously designed twin engine helicopter started series production during 2001-2002. The division is accredited with AS 9100 C & ISO 14001:2004 certifications. The division is also approved by Directorate General of Civil Aviation (DGCA) for CAR 21, CAR 145 & CAR M certifications. HAL with the proven track record of manufacturing more than 700 helicopters, the helicopter division has expand its design, developing & production range by manufacturing new helicopters like Weapon System Integrated (WSI) version of Dhruv (Christened as “Rudra”), Light Combat Helicopter (LCH) and Light Utility Helicopter (LUH).
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2. ALH TRAINING 2.1 Role of Helicopters Few roles of helicopter are as follows:
Patrolling
Army troops transportation
Warfare
Air Ambulance
Rescue operations
2.2 Advanced Light Helicopter (ALH- DHRUV) The Advanced Light Helicopter (ALH-DHRUV) is a twin engine, multi-role, multi-mission new generation helicopter in the 5.5 ton weight cla ss. The basic Helicopter is produced in skid version and wheeled version. Dhruv is “type –Certified” for Military M ilitary operations by the Centre for Military Airworthiness Certification (CEMILAC) and civil operations by the Directorate General of Civil Aviation (DGCA).
2.3 Features of ALH Features of ALH are as follows:
4-Axis digital Automatic Flight Control System
Advanced Cockpit
Hinge less main motor
6-Axis freedom
Anti-resonance isolation system
Bearing less rear motor
2.4 Role of ALH Training Roles of ALH training are as follows:
Training to newly inducted training personnel
Familiarization of maintenance
Pre-flight and ground training to pilots
2.5 Customers Customers of HAL which use ALH are IAF, Navy, Army, Coast guards, Border security force, Govt. of Jharkhand, ONGC, GSI, Mauritius, Nepal, Afghanistan, Maldives, Namibia, Suriname and Ecuador
2.6 ALH Training Classification
Airframe: The airframe of an aircraft is its mechanical structure. It is typically considered to include fuselage, wings and undercarriage and exclude the propulsion system. Airframe design is a field of aerospace engineering that combines aerodynamics, materials
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technology and manufacturing methods to achieve balances of performance, reliability and cost.
Power plant: Two types of power plants used in ALH are following:1. TM 333-2B2 (for DHRUV MK-I and MK-II)& ARDIDEN 1H1 SHAKTI (for DHRUV MK-III & MK-IV) 2. Max power is 801 KW Electrical : ALH is equipped with two electrical systems both DC and AC 1. DC: The DC power specifications is 28A, The DC generator also charges a 24V generator also charges a 24V battery that provides a st and by time of 30min. 2. AC: 115/200V, 3-phase, 400Hz, AC power is generated by an alt ernator coupled to the main gear box. Instruments: There are two types of instruments system:1. DIRECT SENSING TYPE: The measured data reaches the system directly from the sensor module. 2. REMOTE SENSING TYPE: the measured data from sensor is stored and converted in a sub system and then further retried. Avionics: Avionics are the electronic systems used on aircraft, artificial satellites, and spacecraft. Avionic systems include communications, navigation, the display and management of multiple systems, and the hundreds of systems that are fitted to aircraft to perform individual functions
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3. MACHINE SHOP A machine shop is a room or building where machining is done. In a machine shop, machinists use machine tools and cutting tools to make parts, usually of metal or plastic (but sometimes of other materials such as glass or wood). The parts produced can be the end product of the factory, to be sold to customers in the machine industry, the car industry, the aircraft industry, or others. In other cases, companies in those fi elds have their own machine shops The production can consist of cutting, shaping, drilling, finishing, and other processes. The machine tools typically include metal lathes, milling machines, machining centers, multitasking machines, drill presses, or grinding machines, many controlled with CNC. Other processes, such as heat treating, electroplating, or painting of the parts before or after machining, are often done in a separate facility. A machine shop can contain some raw materials (such as bar stock s tock for machining) and an inventory of finished parts. These items are often stored in a warehouse.
3.1 Operations in Machine Shop Various types of operations performed in machine shop are following:
Turning
Grinding
Taper Turning
Gear Cutting
Milling
Drilling
Boring
3.2 Turning Turning is a machining process in which a cutting tool, typically a non-rotary tool bit, describes a helix toolpath by moving more or less linearly while the workpiece rotates. The tool's axes of movement may be literally a straight line, or they may be along some set of curves or angles, but they are essentially linear (in the non-mathematical sense). The cutting of faces on the workpiece (that is, surfaces perpendicular to its rotating axis), whether with a turning tool, is called "facing", and may be lumped into either category as a subset.
3.3 Grinding Grinding is an abrasive machining process that uses a grinding wheel as the cutting tool. A wide variety of machines are used for grinding are:
Hand-cranked knife-sharpening stones (grindstones)
Handheld power tools such as angle grinders and die grinders
Various kinds of expensive industrial machine tools called grinding machines
Bench grinders often found in residential garages and basements
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3.4 Taper Turning When the diameter of a piece changes uniformly, from one end to the other, the piece is said to be tapered. Taper turning as a machining operation is the gradual reduction in diameter from one part of a cylindrical workpiece to another part . Tapers can be either external or internal. internal .
3.5 Gear Cutting Gear cutting is any machining process for creating a gear. The most common gear-cutting processes include hobbing, broaching, milling, and grinding. Such cutting operations may occur either after or instead of forming processes such as forging, extruding, investment casting, or sand casting.
3.6 Milling Milling is the machining process of using rotary cutters to remove material from a workpiece by advancing (or feeding) in a direction at an angle with the axis of the t he tool. It covers a wide variety of different operations and machines, on scales from small individual parts to large, heavy-duty gang milling operations. It is one of the most commonly used processes in industry and machine shops today for machining parts to precise sizes and shapes. Milling machines are of three types :1. Horizontal Milling Machine 2. Vertical Milling Machine 3. Universal Milling Machine
3.7 Drilling Drilling is a cutting process that uses a drill bit to cut a hole of circular cross-section in solid materials. The drill bit is usually a rotary cutting tool, often multipoint. The bit is pressed against the workpiece and rotated at rates from hundreds to thousands of revolutions per minute. This forces the cutting edge against the workpiece, cutting off chips (swarf) from the hole as it is drilled.
3.8 Boring In machining, boring is the process of enlarging a hole that has already been drilled (or cast) by means means of a single-point cutting cutting tool (or of a boring head containing several such tools), tools), such as in boring a gun barrel or an engine cylinder. Boring is used to achieve greater accuracy of the diameter of a hole, and can be used to cut a tapered hole. Boring can be viewed as the internal-diameter counterpart to turning, which cuts external diameters.
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4 - METHODS AND TOOLING 4.1 Methods This department is basically a support department that is concerned with providing the most feasible and the best applicable methods for manufacturing. Alternatively it can be described as the design of the productive process in which a person is involved, the task of the methods engineer is to decide where humans will be utilized in the process of converting raw material to finished product. The terms operation analysis work design and simplifying and corporate re-engineering frequency used interchangeability over cost increase in reliability and productivity of methods of engineering. Figure 2 describes the work of methods department. Design from RWRDC
Study of drawing and standards.
Initial methods
No Design through DLE
Production Queries
Feasiblity check
Yes
Instruction set
Product structure and routing in software
Product structure and routing in software
Process freezing
Process proving
Figure 2: Process chart of Method Department
4.2 Tooling The tooling department plays an important role in manufacturing of tools like jigs and fixtures which are non-standardized in market. The tools are selected for the requirement in manufacturing the project.
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4.2.1 Tooling planning
The process request is received from the methods department. The raw material and sequence tool manufacturing is decided. Reusability of existing tools to carry the new process will also be studied. 4.2.2 Tool design
The tools is designed in specific orientation and demand. The utility of raw material is s elected for tool to ensure the durability, durabilit y, mass and defined properties. The tools design department also tries to reverse engineer tools for reducing in house cost of spare parts cutting tools harness are designed by this section.
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5. HEAT TREATMENT SHOP 5.1 Heat Treatment Heat treating is a group of industrial and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve a desired result such as hardening or softening of a material.
5.2 Heat treatment techniques The heat treatment techniques are as follows:
Annealing: Annealing is a process by which the properties of steel are enhanced to meet machinability requirements. Annealing is a process of heating the steel slightly above the critical temperature of steel (723 degrees Centigrade) and allowing it to cool down very slowly. Case hardening (Carburizing) : Case-hardening or surface hardening is the process of hardening the surface of a metal object while allowing the metal deeper underneath to remain soft, thus forming a thin layer of harder metal met al (called the "case") at the surface. Precipitation Precipitation strengthening: strengthening: Precipitation hardening, also called age hardening or particle hardening, is a heat treatment technique used to increase the yield strength of malleable materials, including most structural alloys allo ys of aluminium, magnesium, nickel, titanium, and some steels and stainless steels. s teels. In super alloys, it is known to cause yield strength anomaly providing excellent high-temperature strength. Tempering: Tempering is a process of heat treating, which is used to increase the toughness of iron-based alloys. Tempering is usually performed after hardening, to reduce some of the excess hardness, and is done by heating the metal to some temperature below the critical point for a certain period of time, then allowing it to cool in still air. Normalizing: Normalization is a process of heat treatment that relieves stress on steel this improves ductility and toughness in steels that may harden after the cold working process. Quenching: Quenching is the rapid cooling of a workpiece to obtain certain material properties. A type of heat treating, quenching prevents undesired low-temperature processes, such as phase transformations, from occurring.
5.3 Furnace Types Furnaces used in heat treatment process are following
Box-type furnace: Many basic box type furnaces have been upgraded to a semi -continuous batch furnace with the addition of integrated quench quench tanks and slow-cool chambers. These upgraded furnaces are a very commonly used piece of equipment for heat- treating.
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Figure 3: Box-type furnace
Pit furnaces: Furnaces which are constructed in a pit and extend to floor level or slightly above are called pit furnaces. Workpieces can be suspended from fixtures, held in baskets or placed on bases in the furnace. Pit furnaces are suited to heating long tubes, shafts and rods by holding them in a vertical position.
Figure 4: Pit Furnace
Salt bath furnaces: Salt baths are used in a wide variety of heat treatment processes including neutral hardening, liquid carburizing, liquid nitriding, austempering, martempering and tempering. Parts are loaded into a pot of molten salt where they are heated by conduction, giving a very readily available source of heat. The core temperature of a part rises in temperature at approximately the same rate as its surface in a salt bath.
Figure 5: Salt-bath furnace
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Vacuum furnaces: A vacuum furnace is a type of furnace in which the product in the furnace is surrounded by a vacuum during processing. The absence of air or other gases prevents oxidation, heat loss l oss from the product through convection, and removes a source of contamination. This enables the furnace to heat materials to temperatures as high as 3,000 °C with select materials.
Figure 6: Vacuum furnaces
Muffle Furnace- A muffle furnace (sometimes retort furnace in historical usage) is a furnace in which the subject material is isolated from the fuel and all of the products of combustion, including gases and flying ash.
Figure 7: Muffle furnace
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6. PROCESS SHOP The surface finishing processes are been covered i n process shop. Surface finishing is a broad range of industrial processes that alter the surface of a manufactured item to achieve a certain property. Finishing processes may be employed to: improve appearance, adhesion or wettability, solderability, corrosion resistance, tarnish resistance, chemical resistance, wear resistance, hardness, modify electrical conductivity, remove burrs and other surface flaws, and control the surface friction.
6.1 Surface finishing processes Few of surface finishing process are described des cribed below
Metal Plating: Metal plating machines use a chemical bath to coat or alter the surface of a substrate with a thin layer of metal, such as nickel, silver, copper & cadmium. The electroplating method generates an electric current to coat the substrate, while electrolyte plating employs an autocatalytic process in which the substrate catalyzes the reaction. Metal plating provides a number of advantages as a finishing process. It can improve a product’s durability, corrosion resistance, surface friction, and exterior exterior appearance. It is also a useful option for coating other metals. In high-volume production runs, a barrelfinishing machine is a fast and efficient plating solution. However, plating machines are generally not suited for smoothing out surface defects. Anodizing: Anodizing is an electrochemical process that converts the metal surface into a decorative, durable, corrosion-resistant, anodic oxide finish. Aluminium is ideall y suited to anodizing, although other nonferrous metals, such as magnesium and titanium, also can be anodized. The anodic oxide structure originates from the aluminium substrate and is composed entirely of aluminium oxide. This aluminium oxide is not applied to the surface like paint or plating, but is fully integrated with the underlying aluminium substrate, so it cannot chip or peel. It has a highly ordered, porous structure that allows for secondary processes such as colouring and sealing. Pickling: Pickling is a metal surface treatment used to remove impurities, such as stains, inorganic contaminants, rust or scale from ferrous metals, copper, precious metals and aluminium alloys. A solution called pickle liquor, which contains strong acids, is used to remove the surface impurities. It is commonly used to descale or clean steel in various steelmaking processes. Powder coating: Powder coating applies a decorative finish that is similar to paint, but with greater durability. The process involves melting dry plastic powder onto the metal to produce a textured, matte, or glossy coating. coati ng. A textured powder-coating machine is also highly effective in removing surface defects. Abrasive blasting: Abrasive blasting is the operation of forcibly propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface, or remove surface contaminants. A pressurized fluid, typically compressed air, or a centrifugal wheel is used to propel the blasting material.
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Sandblasting: Sand-blasting machines are typically employed in projects requiring a uniform matte texture. The process (also known as beadblasting) forces sand, steel shots, metal pellets or other abrasives into a substrate at high speed. This results in a smooth, clean product texture, particularly in soft metals. Polishing: Polishing and buffing are finishing processes for smoothing a workpiece's surface using an abrasive and a work wheel or a le ather strop. Technically polishing refers to processes that use an abrasive that is glued to the work wheel, while buffing uses a loose abrasive applied to the work wheel. Polishing is a more aggressive process while buffing is less harsh, which leads to a smoother, brighter finish. Superfinishing: Superfinishing, also known as micromachining, microfinishing, and short-stroke honing, is a metalworking process that improves surface finish and workpiece geometry. This is achieved by removing just the thin amorphous surface layer left by the last last process with an abrasive stone or tape; this layer is usually about 1μm in magnitude. Superfinishing, unlike polishing which produces a mirror finish, creates a cross-hatch pattern on the workpiece.
6.2 Choosing a Metal Finishing Process There are a few considerations that can help to narrow the choices in selecting a metal finishing technique suitable for the project. Some helpful things to keep in mind are:
Production speed & Process speed Cost-effectiveness : Certain finishing machines (such as vibratory tumblers) can be expensive, but may compensate for their price by delivering faster cycle rates Metal hardness : Harder metals usually require more intense finishing techniques, like grinding, or may need tougher abrasives than those used on softer materials
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7. WELDING & SHEET METAL SHOP 7.1 Welding Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing fusion. In addition to melting the base metal, a filler material is typically added to the joint to form a pool of molten material (the weld pool) that cools to form a joint that is usually stronger than the base material. Pressure may also be used in conjunction with heat, or by itself, to produce a weld. Manufacturing nearly any modern product involves joining various separate components. When a permanent joint is required welding is commonly used. Different types of energy sources can be used for welding includes gas fla mes, electric arc, laser, electron beam, friction & ultrasound.
Figure 8: Electric Arc Welding
Figure 9: Welding symbols
There are two categories of welding process: Fusion welding: The surface of two components to be joined are cleaned placed close together and heated, forming a pool of molten metal that connects the components. A filler rod may be used to add metal to the joint. Pressure welding: A pressure welding process in which macro deformation of the base material to produce coalescence results from the application of heat and pressure. Pressure welding usually involves heating the surfaces to a plastic state and then forcing the metal together. together. The heating can be by electric current of by friction resulting from moving one surface relative to the other. 7.1.1 Types of welding
Types of welding which are available in HAL are:
Gas welding
Electric Arc Welding
TIG(Tungsten TIG(Tungsten Inert Gas ) Welding
Spot Welding
ox yacetylene welding, oxy welding, or gas Gas Welding: Oxy-fuel welding (commonly called oxyacetylene welding in the U.S.) and oxy-fuel cutting are processes that use fuel gases and oxygen to weld and cut metals.
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In oxy-fuel welding, a welding torch is used to weld metals. Welding metal results when two pieces are heated to a temperature that produces a shared pool of molten metal. The molten molte n pool is generally supplied with additional metal called filler. Filler material mate rial depends upon the metals to be welded.
Figure 10: Gas Welding
Oxy-fuel processes may use a variety of fuel gases, the most common being acetylene. Other gases that may be used are propylene, liquefied petroleum gas (LPG), propane, natural gas, hydrogen, and MAPP gas. Many brands use different kinds of gases in their mixes. mixes . Electric Arc Welding: Arc welding is a process that is used to join metal to metal by using electricity to create enough heat to melt metal, and the melted metals when cool result in a binding of the metals. It is a type of welding that uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or nonconsumable electrodes. TIG Welding: Tungsten Inert Gas (TIG) welding, is an arc welding process that uses a nonconsumable tungsten electrode to produce the weld. The weld area and electrode is protected from oxidation or other atmospheric contamination by an inert shielding gas. A constantcurrent welding power supply produces electrical energy, which is conducted across the arc through a column of highly ionized gas and metal vapours known as a plasma.
Figure 11: T.I.G. Welding
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Spot welding: Resistance spot welding (RSW) is a process in which contacting metal surfaces are joined by the heat obtained from resistance to electric current. Work-pieces are held together under pressure exerted by electrodes. The process uses two shaped copper alloy electrodes to concentrate welding current into a small "spot" and to simultaneously clamp the sheets together. Forcing a large current through the spot will melt the metal and form the weld.
Figure 12: Spot Welding Welding Process
Figure 13: Spot Welding Welding Machine
7.2 Sheet Metal Sheet metal is metal formed by an industrial process into thin, flat pieces. It is one of the fundamental forms used in metalworking and it can be cut and bent into a variety of shapes. Countless everyday objects are fabricated from sheet metal. Thicknesses can vary significantly; extremely thin thicknesses are considered foil or leaf, and pieces thicker than 6 mm (0.25 in) are considered plate. There are different types of sheet metal processes available in HAL HA L Bangalore Bangalore are:Bending: Bending is a manufacturing process that produces a V-shape, U-shape, or channel shape along a straight axis in ductile materials. (Refer figure 14) Punching: Punching is performed by placing the sheet of metal stock between a punch and a die mounted in a press. The punch and die are made of hardened st eel and are the same shape. The punch is sized to be a very close fit in the die. The press pushes the punch against and into the die with enough force to cut a hole in the stock. (Refer figure 15)
Figure 14: Bending Machine
Figure 15: Punching Machine
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8. BLADE SHOP Blade shop consist of the following:
Manufacturing of MRB and TRB
Repairing of MRB and TRB
Static balancing tests for MRB and TRB
8.1 Procedure for Blade Manufacturing The MRB & TGB for Cheetah and Cheetal (further modification of Cheetah Helicopter) are been manufactured and repaired for these Aircrafts. The process of manufacturing of MRB is described in steps below:
0.4 mm thick sheet of Aluminium alloy (having ASTM B289)
Vapour Blasting with air, water, sand.
Sulfochromic Sulfochromic pickling to remove excess water, sand, oil or grease.
Folding the sheet into desired shape (symmetric airfoil-NACA0012 ) with the help of jigs and a mechanical press (using dead weight). Adding steel cuff and spar with the help of adhesive filling and heating it at 60°C for 15 min. Filling the inner space with moltoprene foam material. Applying liquid araldite at the opening and let it heat at 165°C for 2 hours in oven for bonding, Let it cool and get riveted and for providing the twist angle (6°) again heat it at 60°C for 5 hours with the help of UV bulbs in a specific mould. Paint will be done after letting the blade cool. After paint static balancing will be done and some weight will be added at the tips of the blades (4gm to 40gm each). Protective casing will be added and all the screws and rivets are applied and sent for the dynamic test. For dynamic test the blade will be mounted on the transmission test unit and vibration tests will be performed and some free weight will be added on the certain points. Now the last part of blade manufacturing the necessary markings markings will be done done to denote the blade type and design year and manufacturer logo.
Figure 16: Cross Section of typical Blade
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Leading Trailin ed e
Honeycom b
Spar
Figure 17: Cross Section of Cheetah Blade
8.2 Servicing The ideal life of a single blade is about 6000 hours or 20 years but need to check after 4-5 years. In repairing of the blades static and dynamic test takes place if the blades are been having any inner problems the disassembly of the blades takes place and the whole procedure mentioned above is repeated.
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9 - STRUCTRAL ASSEMBLY 9.1 Types of Helicopter Construction It can be divided into 3 categories such as 1) Tubular construction 2) Stressed construction 3) Bonded construction 9.1.1 Tubular Construction Construction
This type of structure is still in use in many lightweight aircraft using welded steel tube trusses. A box truss fuselage structure can also be built out of wood—often covered with plywood. Simple box structures may be rounded by the addition of supported lightweight stringers, allowing the fabric covering to form a more aerodynamic shape, or one more pleasing to the eye. Eg. Cheetah, Cheetal.
Figure 18: Truss type design
9.1.2 Stressed Skin Construction
It can be used under semi-monocoque or monocoque. High strength to weight ratio than tubular construction.
Semi-monocoque: It consists of frameworks of vertical and horizontal members covered with metal skin. Vertical members are called bulkhead and formers provide the shape of fuselage. Longerons provide the primary strength while Stiffeners gives mean of attaching and stiffening the skin.
Figure 19: Semi-monocouque
Monocoque: Its construction involves the construction of tubes and cones without internal structural members. It’s is necessary to have formers to maintain the shape but it’s the
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stressed skin that carries the principle stress imposed upon the structure. Eg.-Chetak, Chetan. (Refer figure 20)
Figure 20: Monocouque
9.1.3 Bonded construction:In this type of construction the structural parts are joined together by the chemical methods. Fibre glass, honeycombs and other composite materials that are used in the structure by the use of adhesive, heat and pressure. pre ssure. Eg. - Dhruv, LCH
9.2 Different sections of helicopter structure Different sections of helicopter structure are as follows (Refer figure 21):
Figure 21: Helicopter structural parts
Body structure: It is the main structural member of the fuselage. It does not only carries the load and thrust but also the landing load. It support all other member directly or indirectly. Transmission assembly main rotor is also support by this. In the middle of this structure fuel tank is placed. Bottom structure: It’s made up of two cantilevered beam extending from the box to the cross members of the box. The two beam carry the weight of the cabin and transmit it to the box. The cabin section is directly attached to t he floor. floor. Cabin section: It’s made almost entirely from synthetic material. It’s heat moulded and assembled by ultra-sonic spot welding or riveted to the cabin floor and bulkhead. Rear section: Connects to the body section. It’s made up of 3 frames connected by the beam to the body section. This frame covered with firewall material and act as an attachment point of the engine. Tail boom section is also bolted to the rear section.
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Tail boom section: It consists of tail rotor which provides both the anti-torque and direction. It also includes the drive shaft, tail gear box, vertical fins, horizontal stabilizers, and tail skid. It’s of conventional design-circular fr ames, longerons and outer skins.
Figure 22: Tail Boom Section
Vertical and Horizontal Stabilizers: Fin is bolted to the tail boom at leading edge and spar of section of the fin. It is protected by the tail rotor guard. Horizontal stabilizers produces downward forces to keep the helicopter level in forward flight. It passes through slot and in the tail boom and bolted on each side.
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10. TRANSMISSION ASSEMBLY The transmission system transfers power from the engine to the main rotor, tail ta il rotor, and other accessories. The main components of the transmission system are the main rotor transmission, tail rotor drive system, clutch, and freewheeling unit. Helicopter transmissions are normally lubricated and cooled with their own oil supply. A sight gauge is provided to check the oil level. Some transmissions have chip detectors located in the sump. These detectors are wired to warning lights located on the pilot’s instrument i nstrument panel that illuminate in the event of an m etal shavings are detected, indicating an internal problem.
Figure 23: Helicopter Parts
10.1 Main Rotor Transmission The primary purpose of the main rotor transmission is to reduce engine output RPM to optimum rotor RPM. Suppose the engine speed of of a specific helicopter is 2,700 RPM. Achieving a rotor speed of 450 RPM would require a 6 to 1 reduction. A 9 to 1 reduction would mean the rotor would turn at 300 RPM. Most helicopters use a dual-needle tachometer to show both engine and rotor RPM or a percentage of engine and rotor RPM. The rotor RPM needle normally is used mostly during clutch engagement to monitor rotor acceleration and in autorotation to maintain RPM within prescribed limits. See figure 3-1. In helicopters with horizontally mounted engines, another purpose of the main rotor transmission is to change the axis of rotation from the horizontal axis of the engine to the vertical axis of the rotor shaft. The primar y purpose of the main rotor transmission is to reduce engine engine output RPM to optimum rotor rotor RPM. Suppose the engine engine speed of a specific helicopter is 2,700 RPM. Achieving a rotor speed of 450 RPM would require a 6 to 1 reduction. A 9 to 1 reduction would mean the rotor would turn at 300 RPM. Most helicopters use a dual-needle tachometer to show both engine and rotor RPM or a percentage of engine and rotor RPM. The rotor RPM needle normally is used mostly during clutch engagement to monitor rotor acceleration and in autorotation to maintain RPM within prescribed limits. See figure 24. In helicopters with horizontally mounted engines,
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another purpose of the main rotor transmission is to change the axis of rotation from the horizontal axis of the engine to the vertical axis of the rotor shaft.
Figure 24: Main rotor system
10.2 Tail Rotor Drive System The tail rotor drive system consists of a tail rotor drive shaft powered from the main transmission and a tail rotor transmission mounted at the end of the tail boom. The drive shaft may consist of one long shaft or a series of shorter shafts connected at both ends with flexible couplings. This allows the drive shaft to flex with the tail boom. The tail rotor transmission provides a right angle drive for the tail rotor and may also include gearing to adjust the output to optimum tail rotor RPM. (Refer figure 25)
Figure 25: Tail Rotor Drive System
10.3 Clutch Owing to the greater weight of a rotor in relation to the power of the engine, as compared to the weight of a propeller and the power in an airplane, the rotor must be disconnected from the 24
engine when you engage the starter. A clutch allows the engine to be started and then gradually graduall y pick up the load of the rotor. On free turbine engines, no no clutch is required, as the gas gas producer turbine is essentially disconnected from the power turbine. When the engine is started, there is little resistance from the power turbine. This enables the gas producer turbine to accelerate to normal idle speed without the load of the transmission and rotor system dragging it down. As the gas pressure increases through the power turbine, the rotor blades begin to turn, slowly at first and then gradually accelerate to normal operating RPM. On reciprocating helicopters, the two main types of clutches are the centrifugal centri fugal clutch and the belt drive clutch.
Centrifugal Clutch : The centrifugal clutch is made up of an inner assembly and an outer drum. The inner assembly, which is connected to the engine driveshaft, consists of shoes lined with material similar to automotive brake linings. At low engine speeds, springs hold the shoes in, so there is no contact with the outer drum, which is at tached to the transmission input shaft. As engine speed increases, centrifugal force causes the clutch shoes to move outward and begin sliding against the outer drum. The transmission input shaft begins to rotate, causing the rotor to turn, slowly at first, but increases as the friction between the clutch shoes and transmission drum increases. As rotor speed increases, the rotor tachometer needle shows an increase by moving toward the engine tachometer needle. When the two needles are superimposed, the engine and the rotor are synchronized, indicating the clutch is fully engaged and there is no further sli ppage of the clutch shoes. Belt Drive Clutch: Some helicopters utilize a belt drive to transmit power fr om the engine to the transmission. A belt drive consists of a lower pulley attached to the engine, e ngine, an upper pulley attached to the transmission input shaft, shaft, a belt or a series of V-belts, and some means of applying tension to the belts. The belts fit loosely over the upper and lower pulley when there is no tension on the belts. This allows the engine to be started without any load from the transmission. Once the engine is running, tension on the belts is gradually increased. When the rotor and engine tachometer needles are superimposed, the rotor and the engine are synchronized, and the clutch is then fully engaged. Advantages of this system include vibration isolation, simple maintenance, and the ability to start and warm up the engine without engaging the rotor.
10.4 Freewheeling Unit
Since lift in a helicopter is provided by rotating airfoils, these airfoils must be free to rotate if the engine fails. The freewheeling unit automatically disengages the engine from the main rotor when engine RPM is less than main rotor RPM. This allows the main r otor to continue turning at normal in-flight speeds. The most common freewheeling unit assembly consists of a oneway “sprag” clutch located between the engine and main rotor transmission. This is usually in the upper pulley in a piston helicopter or mounted on the engine gearbox in a turbine t urbine helicopter. When the engine is driving the rotor, inclined surfaces in the sprag clutch force rollers against an outer drum. This prevents the engine from exceeding transmission RPM. If the engine fails, the rollers move inward, allowing the outer drum to ex ceed the speed of the inner portion. The transmission can then exceed the speed of the engine. In this condition, engine speed is less than that of the drive system, and the helicopter is in an autorotative state.
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11. QUALITY & PROGRAMME PROGRAMME ENGINEERING 11.1 Quality Engineers and test operators commonly use data acquisition hardware and software to verify functionality and ensure the quality of finished goods. This may include a wide range of manual or automated electrical, mechanical, or environmental tests. The following case studies illustrate the reliability, accuracy, and flexibility provided by data acquisition hardware and LabVIEW software for manufacturing and quality test. The challenge is of ensuring high quality of manufacturing increases when the manufacturing of your products are been done in other locations of your company or by a subcontractor. In both cases, your control over quality quality of process is limited. Product testing seeks to ensure that consumers can understand what products will do for them and which products are the best value. Product testing is a strategy to increase consumer protection. Quality assurance (QA) is a way of preventing mistakes or defects in manufactured products and avoiding problems when delivering solutions or services to customers; which ISO 9000 defines as "part of quality management focused on providing confidence that quality requirements will be fulfilled" Quality assurance comprises administrative and procedural activities implemented in a quality system so that requirements and goals for a product, service or activity will be fulfilled. It is the systematic measurement, comparison with a standard, monitoring of processes and an associated feedback loop that confers error prevention. This can be contrasted with quality control, which is focused on process output. Quality assurance includes two principles: "Fit for purpose" (the product should be suitable for the intended purpose); and "right first time" (mistakes should be eliminated). A includes management of the quality of raw materials, assemblies, products and components, services related to production, and management, production and inspection processes. The two principles also manifest before the background of developing (engineering) a novel technical t echnical product: The task of engineering is to make it work once, while the task of quality assurance is to make it work all the time.
11.2 Programme Engineering Supervising project engineering related tasks including planning, control & troubleshooting for achieving the planned periodic schedules and process control. Coordinating with the other departments for smooth functioning and accomplishing production as per customers’ requirement & organizational guidelines. It is responsible for project progress, central scheduling, availability of machines and raw material.
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12. DLE It applies knowledge of design principles to assess and resolve product/process issues through the product lifecycle. Analysis, conducts root cause analysis and develo ps dispositions for design non-conformances. Applies engineering principles to research technical, operational and quality issues that cannot be resolved by customer and designs interim and final engineering solutions. Identifies documents, analyses reported problems and communicates deviations that could impact design intent and safety; recommends and manages resolution. Develops and implements product/process improvements. Supports Integrated Product Teams (IPT) and participates in design reviews. Represents the engineering community in the build through post production environment. Ensures supplier and build partner compliance with standards. Develops customer correspondence for continued safe operation and maintenance of equipment. Participates in on-site disabled product repair teams and accident investigation or support team. Analysis damage repair or structural modification to determine appropriate jacking and shoring, prevent collateral damage dama ge and assure a safe work environment. Designs interim structural repairs and conducts static strength analysis. Develops non-destructive test procedures, tools and standards. Conducts simple static strength analysis.
Coordinates activities to evaluate and resolve engineering-related production problems encountered in assigned area of aircraft manufacturing facility: Reviews production schedules, engineering specifications, orders, and related information to maintain current knowledge of manufacturing methods, procedures, and activities in assigned area. Confers with quality control, material, manufacturing, and other department personnel to provide technical support. Interprets engineering drawings and facilitates correction of errors on drawings and documents identified during manufacturing operations. Investigates reports of defective, damaged, or malfunctioning parts, ass emblies, equipment, or systems to determine nature and scope of problem. Examines, measures, inspects, or tests defective part for conformance to engineering design drawings or blueprint specifications, using precision measuring and testing instruments, devices, and equipment. Consults with project engineers to obtain specialized information. Evaluates findings to formulate corrective action plan and coordinates implementation of plan. Maintains records or oversees recording of information by others to ensure engineering drawings and documents are current and that engineering-related production problems and resolutions are documented.
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13. FINAL ASSEMBLY Final Assembly is the final stage in the manufacture of a helicopter. During final assembly, subassemblies and other components are installed into the airframe. These parts come from internal and17external suppliers around the world. Quality checks and operational checks are performed as assembly progresses. Flight operations operations include painting defueling of the aircraft, performing a ground run to ensure proper operation of aircraft systems prior to flight, and passing flight acceptance tests. Final assembly begins with receipt of the airframe. The airframe is the basic fuselage structure of the aircraft and is constructed of sheet metal or, in some cases, composite materials. During final assembly, subassemblies and other components are installed into the airframe. Systems installed include the wiring, tail rotor pylon, exhaust systems, engines, transmission, oil cooler, control systems, and avionics. The final assembly build is comprised of hundreds of installations to install these systems into the helicopter. Each installation is called an AOS (Assembly Operation Sequence). Each AOS consists of many operations that must be followed to ensure proper assembly of the helicopter. These include quality checks performed by the Quality Assurance (QA) department. If there is a problem with the installation of a component, QA inspectors record the problem, and it must be fixed before that operation can be completed and signed off. The structure of the helicopter is installed with the various systems such as transmission, electrical, avionics, automatic flight control system, missile system integration and weapon system integration. It also includes the mounting of the helicopter blades. Final paint job and finishing of the helicopter is done as per the requirements of the customer. 13.1 Electrical System
There are 3 main system for electrical power- EPR (electrical power receptacle), generators and battery. battery.
EPR provide power to helicopter externally when it is on the ground.
Generators is the primary source for 28 V DC power and also charges the batteries.
It is also includes the various lighting installed on the helicopter.
Integrated Architectural Display has two DMC (display management computer), two DIU (digital interface unit), two CDS (cockpit display unit) and four MFDs (main flight display). FADEC (fully authority digital engine control) controls the sequence for engine starting engine idling and engine shutdown. The ALH FADEC control also comes with auto reflight features which is a system that executes the start up when a previous attempt has failed, usually used for cold starts.
13.2 Avionics
Intercom which enables the communication between the pilot and the co-pilot. HFSSB (high frequency single sideband) communication is used t o send messages over long distances but is rarely used due to excessive interference. 28
V/UHF is used to enable the communication exterior to the aircr aft.
IFF (identification of friend and foe) is a system that transmit a coded message messa ge that contains the information about the pilot, the squadron he’s flying. A friend aircraft will have the same system transmit back a message of the same format and a foe aircraft will not.
MADRAS also known black box contains two module FDR (flight data recorder) and CVR (cockpit voice recorder). It can withstand up t o 3400g, 260°C for 10 hours and 1100°C for 1 hour.
13.3 AFCS (automatic flight control system)
It contains a PCU (pilot control unit), AFSC computer, AHRS (attitude and heading reference system), s ystem), ADU (air data unit), Vertical Gyro and Magnetometer. The AFCS has a control module in the cockpit that has the following functions: hold height, hover height, airspeed, turn coordinator and heading.
13.4 MSI (mission system integration)
EW (electronic warfare) Suite contains the three sensor i.e. missile, la ser and radar in four quadrants. It can detect an approaching missile radar tracking signal and laser tracking signals falling on the helicopter. FCD (flare and chaff dispenser) is a counter measure system that dispenses high temperature flares or metallic chaffs, to divert heat sinking and metal seeing missiles respectively. respectively. HPS (helmet pointing system) comes in the form of HUD (head up display) manufactured by IAI (Israel aerospace industries).The system comprises of a set of cameras and laser device that scan the retina of the eye and project a virtual screen. EO (electro optical) pod is a spherical module that contains two cameras, one for day time use and one for night vision.
13.5 WSI (weapon system integration)
Weapon Jettison is a system to designed to dispense all weapons when a crash landing might occur. Turret gun is a gun of capable ca pable of firing 300 round at once. ALH is capable of carrying the four missiles. The missile firing system is at a default to fire the outboard missiles first. ALH can also carry four rocket launchers that can house 12 rockets. Fixed Sight is a system used to guide the missiles. It uses EO pod to pin point the target and guide the missiles.
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14. CIVIL HELICOPTERS To exploit the national and international market potential in the 4 to 5 ton weight class, Civil Variant of ALH was taken up. It is mainly intended to be used in the transport role, commuter, offshore as well as VIP roles. Additional roles such as emergency medical service, rescue, utility, law enforcement are also envisaged. First flight of ALH civil variant was carried out successfully on 6th Mar’2002 & demonstrated at Aero-India Aero -India 2003 and 2005. Certification for Civil wheel version was obtained in Oct.’03 and for civil Skid Version Vers ion obtained in Jul.’04. PT 2 basic version was converted to Air Ambulance version and demonstrated during Aero India 2001. Further, ALH capabilities were successfully demonstrated in Chile with IAI-LAHAV’s IAI- LAHAV’s centralized avionics package. After the successful Type certification of ALH civil variant upto five ALH civil helicopters are in service with various operators like ONGC, IAI, BSF, GSI and Govt. of Jharkhand. The revalidation of ALH civil variant Type Certifi cate with DGAC, Chile has been completed in April 2007. This is the first re-validation accorded by any foreign airworthiness authority to an Indian Aircraft. The certification with EASA is under progress and FAA is being pursued MK-I
It is a Utility Utilit y Version with Conventional Cockpit & 2B2 Engine, its specifications are described below:
Max take-off Weight: 5500 Kg
Fuel Capacity: 1055 Kg
Useful Load: 2490 Kg
Never exceed speed: 295 km/h
Service Ceiling: 6500 m
Under Slung: 1500 Kg
Mk-II
It is a Utility Version with Glass Cockpit & 2B2 Engine, its specificat ions are described below:
Max take-off Weight: 5500 Kg
Fuel Capacity: 1055 Kg
Never exceed speed: 292 km/h
Useful Load: 2100 Kg
Service Ceiling: 6500 m
Under Slung: 1500 Kg
Civil variants
Dhruv (C): Also known as ALH-Civil, a Turbomeca TM333-2B2-powered 12-seat helicopter, type certificate issued on 31 October 2003.
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Dhruv (CFW): A Turbomeca TM333-2B2-powered 12-seat helicopter fitt ed with wheels, type certificate issued on 20 April 2005. Dhruv (CS): A Turbomeca TM333-2B2-powered 12-seat helicopter fitted with skids, type certificate issued on 30 July 2004. Garuda Vasudha: A Dhruv outfitted with a heliborne geophysical survey system (HGSS).
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BIBLIOGRAPHY
www.hal-india.com/Product_Details.aspx?Mkey=54&lKey=&CKey=24
https://en.wikipedia.org/wiki/HAL_Dhruv
http://www.hal-india.com/Helicopter%20Complex/M__124
http://www.hal-india.com/Rotary%20Wing/M__147
https://www.faasafety.gov/gslac/ALC/course_content.aspx?cID=105&sID=461&prev iew=true
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