HAL Report

1. INDUSTRIAL TRAINING REPORT
ON
BASICS OF AIRCRAFT
IN
HINDUSTAN AERONAUTICS
LIMITED (HAL), LUCKNOW








SUBMITTED BY :-
Shubham Khandelwal
Mechanical Engineering
Roll no. - 1109040192
SUBMITTED TO :-
Mr. Amit Yadav

2. Page 1


PREFACE
Training has misinterpreted by most of us as a platform for project performation. Industrial
training in true sense has been included in curriculum to make the student
wellversed with the technical procedure of various industries, the basic criteria for management
of various resources in a company or industry.
The educational institution sole aim by industrial training is to improve the technical knowledge
and to have a hand on experienced to make them realistic in thinking, to understand the
procedure for manufacturing keeping mind the minute detail which will benefit the customer like
no learning is proper without implementation.
Doctors, Lawyers, hotel management student surely hold an upper hand. It’s because right from
the second year of their graduation they are made to face the world and their problems with a
tender mind.
Unlike the pitiable engineers like us who are completely isolated from industry. Therefore there
should be industry institutions made compulsory for every engineering institute.

3. Page 2


ACKNOWLEDGEMENT
With deep devotion I thank all mighty God for blessing me with desire, intention, inclination,
will, ability, guidance hope and achievements of required goal.
The present dissertation entitled “Basics of Aircraft” in partial fulfillment for the Degree of
Bachelor of Technology, University of Uttar Pradesh.
I would like to express my gratitude to all those who gave me the possibility to complete this
project. I want to thank Hindustan Aeronautics Limited for giving me the permission to
commence this project in the first instance, to do the necessary research work and to use
Technical Departmental data. Would take this opportunity as a proud privilege to express my
deep felt of gratitude to Mr. Manoj Kumar (Senior Manager Technical Training Centre.).
Last but not the least, I also wish to acknowledge my indebtedness to the staff of H.A.L. without
whose co-operation, this training would not have not been successful. The training at H.A.L.
Lucknow was full of responsiveness & it gave me the rare opportunity to correlate the theoretical
knowledge with the practical one. Being well known company of India & abroad, it gave me the
opportunity to learn the work carried out here, got a glimpse of new environment & hard work of
industrial unit.

4. Page 3


DECLARATION
I hereby declare that this project work entitled “Basics of Aircraft” submitted by me in the
partial fulfillment for the degree of Bachelor of Technology is an authentic record of my own
work carried out at Hindustan Aeronautics Limited, Lucknow as requirement of 4 weeks project
during 1st JULY to 31ST JULY, 2014
Date:
Place: Gr. Noida












Shubham Khandelwal
B.Tech (Mechanical, 4
th
yr)
1109040192

5. Page 4


CONTENTS
 Introduction
 History of HAL
 Products of HAL
 Services of HAL
 Vision and Mission and Values
 Objectives and Strategies
 Organisational growth
 Organisational structure
 Divisions of HAL
 Accessories Division Lucknow
 Products of HAL ADL
 Services of HAL ADL
 Basics of Aircraft
 Basic theory of flight
 How lift is generated?
 Axes of rotation
 Structure of Aircraft
 Components of Aircraft
 Fuselage
 Wings
 Empennage
 Power plant
 Landing gears
 Aircraft Flight Controls
 Conclusions
 References

6. Page 5


INTRODUCTION

Hindustan Aeronautics Limited based in Bangalore, India, is one of
Asia's largest aerospace companies. Under the management of
the Indian Ministry of Defence, this state-owned company is mainly
involved in aerospace industry, which includes manufacturing and
assembling aircraft, navigation and related communication equipment,
as well as operating airports.
HAL built the first military aircraft in South Asia and is currently
involved in the design, fabrication and assembly of aircraft, jet engines, and helicopters, as well
as their components and spares. It has several facilities spread across several states in India
including Nasik, Korwa, Kanpur, Koraput, Lucknow, Bangalore and Hyderabad. The German
engineer Kurt Tank designed the HF-24 Marut fighter-bomber, the first fighter aircraft made in
India.
Hindustan Aeronautics has a long history of collaboration with several other international and
domestic aerospace agencies such as Airbus, Boeing, Lockheed Martin, Sukhoi Aviation
Corporation, Elbit Systems, Israel Aircraft Industries, RSK MiG, BAE Systems, Rolls-Royce
plc, Dassault Aviation, MBDA, EADS, Tupolev, Ilyushin Design Bureau, Dornier
Flugzeugwerke, the Indian Aeronautical Development Agency and the Indian Space Research
Organisation.

7. Page 6


HISTORY OF HAL
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 658 Aircraft/Helicopters, 4178 Engines, Upgraded 272 Aircraft and overhauled
over 9643Aircraft and 29775 Engines.
HAL has been successful in numerous R & D programs developed for both Defence 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)
 Various military and civil upgrades.
Dhruv was delivered to the Indian Army, Navy, Air Force and the Coast Guard in March
2002, in the very first year of its production, a unique achievement.

HAL has played a significant role for India's space programs by participating in the manufacture
of structures for Satellite Launch Vehicles like

8. Page 7


 PSLV (Polar Satellite Launch Vehicle)
 GSLV (Geo-synchronous Satellite Launch Vehicle)
 IRS (Indian Remote Satellite)
 INSAT (Indian National Satellite)
Apart from these, other major diversification projects are manufacture & overhaul of Industrial
Marine Gas Turbine and manufacture of Composites.
HAL has formed the following Joint Ventures (JVs) :
 BAeHAL Software Limited
 Indo-Russian Aviation Limited (IRAL)
 Snecma-HAL Aerospace Pvt Ltd
 SAMTEL-HAL Display System Limited
 HALBIT Avionics Pvt Ltd
 HAL-Edgewood Technologies Pvt Ltd
 INFOTECH-HAL Ltd
 TATA-HAL Technologies Ltd
 HATSOFF Helicopter Training Pvt Ltd
 International Aerospace Manufacturing Pvt Ltd
 Multi Role Transport Aircraft Ltd
Several Co-production and Joint Ventures with international participation are under
consideration.
HAL's supplies / services are mainly to Indian Defence Services, Coast Guard and Border
Security Force. Transport Aircraft and Helicopters have also been supplied to Airlines as well as
State Governments of India. The Company has also achieved a foothold in export in more than
30 countries, having demonstrated its quality and price competitiveness.
HAL was conferred NAVRATNA status by the Government of India on 22nd June 2007.

9. Page 8


The Company scaled new heights in the Financial Year 2010-11 with Turnover of Rs.13, 116
Crores and PBT of Rs 2,841 Crores.
HAL has won several International & National Awards for achievements in R&D, Technology,
Managerial Performance, Exports, Energy Conservation, Quality and fulfillment of Social
Responsibilities.
 HAL was awarded the “INTERNATIONAL GOLD MEDAL AWARD” for Corporate
Achievement in Quality and Efficiency at the International Summit (Global Rating Leaders
2003), London, UK by M/s Global Rating, UK in conjunction with the International
Information and Marketing Centre (IIMC).
 HAL was presented the International - “ ARCH OF EUROPE ” Award in Gold Category in
recognition for its commitment to Quality, Leadership, Technology and Innovation.
 At the National level, HAL won the "GOLD TROPHY" for excellence in Public Sector
Management, instituted by the Standing Conference of Public Enterprises (SCOPE).
Some of the prestigious Awards received during 2009-10 & 2010-11 are:
2009-10
 “MoU Excellence Award” for the top performing CPSEs for the year 2006-07(Top Ten
Public Sector Enterprises).
 Raksha Mantri’s Award for Excellence for the year 2007-08 under the “Institutional”
category.
 “Regional Export Award” from EEPC, India for the year 2007-08.
 “The Supplier of the year 2009” by Boeing, USA.
2010-11
 “MoU Excellence Award” for the top performing CPSEs for the year 2008-09.
 Raksha Mantri's Award for Excellence for the years 2008-09, for Export under the
“Institutional” category.

10. Page 9



 International Aerospace Awards (instituted by SAP Media Worldwide Ltd) as mark of
recognition to the Indian Industry for excellence in innovation, indigenous technology and
entrepreneurship.
 Golden Award for Quality and Business Prestige from Otherways Management Association
Club, France
 Performance Excellence Award -2009 (Organisation) for the year 2008-09 by Institution of
Industrial Engineering.
2011-12
 Raksha Mantri’s award for excellence in performance for 2009-10. The award was handed
over by Hon’ble Raksha Mantri, to off. Chairman, HAL on 14 Nov 2011.
 “Regional Export Award” from EEPC India for the year 2009-10.
 “Best Exporter Award 2011 in special category (Gold)” from Federation of Karnataka
Chambers of Commerce & Industry (FKCCI)
2012-13
 HAL has been selected for Raksha Mantri’s awards for excellence for the year 2010-11 under
Institutional category.
 HAL bagged “Digital Inclusion Award - 2012” for ERP and e-procurement implementation
across the Company in the silver Category. The award was presented on 18 Sep 2012.
 HAL bagged “Digital Inclusion Award - 2012” for ERP and e-procurement implementation
across the Company in the silver Category. The award was presented on 18 Sep 2012.
 Performance Excellence Award for the year 2010-11 by Institution of Industrial Engineering.

11. Page 10


PRODUCTS OF HAL


SU-30 MKI


Light Combat Aircraft (Tejas)

12. Page 11



Advanced Light Helicopter (Dhruv)



Communication/Navigation Equipments

13. Page 12



Advanced Communication Equipments


Accessories for Aircraft and Helicopters

14. Page 13



Aerospace Equipments


Aero Engines of Russian Origin


Aero Engines of Western Origin

15. Page 14


SERVICES OF HAL

16. Page 15


MISSION, VISSION AND VALUES
Mission
" To achieve self reliance in design, development, manufacture, upgrade and maintenance of
aerospace equipment diversifying into related areas and managing the business in a climate of
growing professional competence to achieve world class performance standards for global
competitiveness and growth in exports. ".
Vision
"To make HAL a dynamic, vibrant, value-based learning organization with human resources
exceptionally skilled, highly motivated and committed to meet the current and future challenges.
This will be driven by core values of the Company fully embedded in the culture of the
Organization"
Values
We are committed to these values to guide us in our activities.
Customer satisfaction :- We are dedicated to building a relationship with our customers where
we become partners in fulfilling their mission. We strive to understand our customer’s needs and
to deliver products and services that fulfill and exceed all their requirements.
Commitment to total quality :- We are committed to continuous improvement to all our
activities. We will supply products and services that conform to highest standards of design,
manufacture, reliability, maintainability and fitness for use as desired by our customer.
Cost and time consciousness :- We believe that our success depends on our ability to continually
reduce the cost and shorten the delivery period of our products and services. We will achieve this
by eliminating waste in all activities and continuously improving all processes in every area of
our work.

17. Page 16


Innovation and creativity :- We believe in striving for improvement in every activity involved in
our business by pursuing and encouraging risk- taking, experimentation and learning at all levels
within the company with a view to achieving excellence and competitiveness.
Trust and team spirit :- We believe in achieving harmony in work-life through mutual trust,
transparency, co-operation and sense of belonging. We will strive for building empowered teams
to work towards achieving organization goals.
Respect for the individual :- We value our people. We will treat each other with dignity and
respect and strive for individual growth and realization of every one’s full potential.
Integrity :- We believe in a commitment to be honest, trustworthy and fair in all our dealings. We
commit to be loyal and devoted to our organization. We will practice self-discipline and own
responsibility for our actions. We will comply with all requirements so as to ensure that our
organization is always worthy of trust.

18. Page 17


OBJECTIVES AND STRATEGIES
Objectives
In April, 1971 the board of directors of HAL appointed a committee of HAL to review
the total functioning of the company and make its recommendations. One of the study teams set
up by committee had gone into various aspects of the objectives of HAL in great detail and made
valuable suggestions for determining the objectives of HAL.
The objectives of HAL can be stated as :
 To ensure availability of Total Quality People to meet the Organizational Goals and
Objectives
 To have a continuous improvement in Knowledge, Skill and Competence (Managerial,
Behavioral and Technical
 To promote a Culture of Achievement and Excellence with emphasis on Integrity, Credibility
and Quality
 To maintain a motivated workforce through empowerment of Individual and Team- building
 To enhance Organizational Learning
 To play a pivotal role directly and significantly to enhance Productivity, Profitability and
improve the Quality of Work Life

Strategies
 To be in total alignment with Corporate Strategy
 Maintain Human Resource at optimum level to meet the objectives and goals of the
Company
 Be competent in Mapping, Analysis and Upgradation of Knowledge and Skills including
Training, Re-training, Multi-skilling etc

19. Page 18


 Cultivate Leadership with Shared Vision at various levels in the Organization
 Focus on Development of Core Competence in High-Tech areas
 Build Cross-functional Teams
 Create awareness of Mission, Values and Organizational Goals through out the Company
 Introduce / Implement personnel policies based on performance that would ensure growth,
Rewards, Recognition, Motivation

20. Page 19


ORGANISATIONAL GROWTH OF HAL
1940: H.A.L was set up by Seth Warchand Hirachand in association with the government of
Mysore as a private limited company.
1941: First product “HARLOW TRAINER AIRCRAFT” & “CURLINESS HAWK
AIRCRAFT” handed over to government of India.
1942: Company was handed over to the U.S. AIR FORCE. HAL repaired over 100 different
varieties of aircraft and 3800 piston engines.
1945: Government of India took over the management of HAL again after the Second World
War.
1949: First percivical apprentice aircraft assembled.
1951: The control of HAL was shifted to ministry of defence from ministry of industry.
1954: The first HINDUSTAN TRAINER II (HT—II) had its maiden flight.
1956: HAL comes under the public sector.
1960: Aircraft Manufacturing Department at Kanpur was established.
1962: HINDUSTAN AERONAUTICS INDIA LIMITED (HAIL) was formed to manufacture
MIG-21 aircraft. Three factories at Nasik, Koraput, and Hyderabad were established.
1964: HAIL was dissolved and its assets merged with aeronautics India limited and company
by the name of HAL was formed.
1969: An agreement with USSR AWS reached for the license production of MIG-21
AIRCRAFT.
1970: Helicopters Division was established to manufacture Helicopters.

21. Page 20


1973: Lucknow Division was formed for manufacture of more than 500 types of Instruments
and Accessories.
1976: An agreement with USSR for license for MIG-21 AND BIS –AIRCRAFT.
1979: Agreement with British aerospace for manufacture JAGUAR AIRCRAFT.
1982: Agreement with USSR for license manufacturing of MIG-27M AIRCRAFT.
1983: Korwa Division lraged division for HAL formed.
1990: Design and Development of Advanced Light Helicopter.
1996: Major servicing of the first batch of MIRAGE – 2000 AIRCRAFT was under taken. It
conducted several “C” CHECKS ON BOEING 737 AIRCRAFT.
1998: IGMT a new Division was established at Bangalore.
1998: Establishment of Industrial & Marine Gas Turbine Division for aerodoriative gas
turbines / Industrial engines.
2000: Establishment of Airport Service Service Centre for C0-ordinating the operations at HAL
Airport – Bangalore.
2002: Establishment of Sukhoi Engine Division at Koraput.
2002: Expansion of Nasik Division as Aircraft Manufacturing Division and Aircraft Overhaul
Division.
2006: HAL ranked 45
th
among Top Defense Firm in the World.
2006: 19
th
July, HAL – IAI cooperation in Aero structure.
2006: 21
st
July, Rolls – Royce & HAL celebrate 50 year of partnership.
2006: HAL launches newspaper from Minsk square on 1
st
September.

22. Page 21


2006: 3
rd
September, SU-30 MKI Programme on schedule: HAL.
2006: 14
th
October, HAL Launches Helicopter ambulance, Charter Service named “Vayu
Vahan”.
2006: 20
th
December, HAL receives EEPC Award for the year 2004-05.
2007: 5
th
June, HAL completes planting 25 Lakh saplings.
2007: 22
nd
June, HAL gets Navratna Status.
2007: 2
nd
July, Ashok Nayak is HAL’s new MD.
2007: 6
th
August, HAL ranked 34
th
among top 100 defence firm in the world.
2007: 16
th
August, DHRUV with SHAKTI ENGINE and Weapons make maiden flight.

23. Page 22


ORGANISATION STRUCTURE
HAL CORPORATE
























Figure (1) Organization Structure

DESIGN
COMPLEX
 Aircraft R & D
Center
 Rotatory wing R
& D Center
 Engine & Test
bed R & D
Center
 Strategic
Electronics R & D
Center
 Aircraft Updates
R & D Center
 Aerospace
System &
Equipment R & D
Center
 Gas Turbine R &
D Center
 Control
Materials &
Processes lab &
NDT Center R &
D Center
BANGLORE
COMPLEX
 Aircraft
Division
 Engine Division
 Foundry &
Forge Division
 Helicopter
Division
 Aerospace
Division
 Overhaul
Division
 Industrial &
Marine gas
Turbine
Division

ACCESSORIES
COMPLEX
 Accessories
Division
Lucknow
 Avionics
Division Korwa
 Avionics
Division
Hyderabad
 Transport
Aircraft
Division
Kanpur

MIG
COMPLEX
 Nasik
Division
 Koraput
Division

24. Page 23


DIVISIONS OF HAL
All over India H.A.L has 7 divisions; these divisions are dedicated for different purpose related to
the manufacturing of commercial and fighter aircrafts. The divisions are as follows:
1. Bangalore Division It is divided into 5 divisions:
a) Air craft division, which also consist a runway.
b) Engine division, which is indulged mainly in manufacturing of LCA Engine.
c) Helicopter division.
d) Overhaul division.
e) Design bureau.
2. Nasik DivisionIt is currently dealing with Russian accessories repair, overhaul and
manufacturing which are used in aircrafts.
3. Kanpur DivisionIt is dealing with assembly of whole commercial aircrafts like Puspak,
Dornier and other major products are DO-228, HPT-32 and Civil aircrafts etc.
4. Lucknow DivisionIt is an accessories division which deals with manufacturing of more
than 1400 accessories like, alternator, generators, tachometer, tacho generator and other major
products are Landing gear, Wheels, Brakes, Hydraulic & Fuel accessories, aircraft instruments
GSE, GHE & ECS etc.
5. Korwa DivisonIt also deals with design and manufacturing of accessories (mainly
electronics) and other major products are INS, HUDWAC, NAV attack LRMTS, FDR, Auto
Stab System.
6. Koraput Division It is indulged in assembly of engines of aircraft.
7. Hyderabad Division It is an accessories division. They manufacture accessories like
Surveillance Radar, Precision Approach Radar, INCOM, RAM, IFF, VHF / UHF (5).

25. Page 24


ACCESSORIES DIVISION LUCKNOW

Accessories Division of HAL was established in
1970 with the primary objective of manufacturing
systems and accessories for various aircraft and
engines and attain self sufficiency in this area. Its
facilities are spread over 116,000 sqm of built area
set in sylvan surroundings. At present it is turning
out over 1300 different types of accessories. The
Division started with manufacturing various Systems
and Accessories viz, Hydraulics, Engine Fuel System, Air-conditioning and Pressurization,
Flight Control, Wheel and Brake, Gyro & Barometric Instruments, Electrical and Power
Generation & Control System, Undercarriages, Oxygen System and Electronic System all under
one roof to meet the requirements of the aircraft, helicopters and engines being produced by
HAL like MiG series of aircrafts, Dornier, Jaguar, Advanced Light Helicopters(ALH), PTA,
Cheetal & Su-30 and repair / Overhaul of Avro, AN-32, HPT-32, Mirage-2000 & Sea-Harrier
aircrafts, Cheetah and Chetak helicopters.
The Division undertakes manufacturing and serviceing of accessories under Transfer of
Technology (ToT) from more than 40 licensor from different countries. In addition, a lot of
emphasis has been given on developing indigenous capability for Design and Development of
various systems and accessories. This capability has culminated in indigenous design and
development of over 350 types of accessories for the Light Combat Aircraft (LCA) (Air force
and Navy version), Advanced Light Helicopter (all versions i.e. Army, Air force, Navy & Civil),
SARAS and IJT (Intermediate Jet Trainer). The Division has also developed and has made
successful strides into the area of Microprocessor based control systems for the LCA Engine as
well as other systems.

26. Page 25


The Division has been in the forefront of accessories
development and supply not only to Indian Force but to
Army, Navy, Coast Guard and various Defence
Laboratories as well as for Space applications.
The Division is networked with all sister Divisions and
R& D Centers by LAN/WAN. Lean manufacturing and
ERP have been implemented to create an efficient
manufacturing system.
The Division today has a prime name in the Aviation market and various international companies
are interested to join hands with it for future projects.
The Division has also made steady progress in the area of Export.

27. Page 26


Products of HAL ADL
 Hydraulic system and power control
Hydraulic Pumps, Accumulators, Actuators, Electro-selectors, Bootstrap Reservoirs and
various types of valves
 Environmental control system
Cold Air Unit, Water Extractors, Non Return Valves and Venturies
 Engine fuel control system
Fuel after Burner regulator and distributor, Main Fuel Distributor, Regulator and After
Burner Pump, Plunger Pumps, Fuel Metering Device
 Instruments
Electrical Indicators, Fuel quantity and flow metering instruments, Flight instruments,
Sensors and Switches
 Electrical power generation and control system
AC/DC Generator, Control and Protection Units, AC and DC Master Box, Inverters,
Transformer Rectifier Unit, Actuators
 Undercarriage, wheels and brakes
Main and Nose Undercarriage, Main and Nose Wheel, Brake System LRUs
 Test rigs
Dedicated Test Rigs, custom-built Fuel/Hydraulic Test Rigs and Electrical Test Rigs

28. Page 27


Services of HAL ADL
Repairs, major servicing and supply of spares
The Division carries out Repair and Overhaul of Accessories, with minimum turn-around-time.
Site Repair facilities are offered by the Division by deputing team of expert Engineers /
Technicians.
Services provided for:
Military Aircraft
 MiG Series
 Jaguar
 Mirage-2000
 Sea - Harrier
 AN-32
 Kiran MK- I / MK- II
 HPT - 32
 SU-30 MKI
Civil Aircraft
 Dornier-22B
 AVRO HS-748
Helicopters
 Chetak (Alouette)

29. Page 28


 Cheetah (Lama)
 ALH (IAF / NAVY / COAST GUARD / CIVIL)
Sub-contract Capabilities
 The Division has comprehensive manufacturing capabilities for various Hi-tech components,
Equipment and Systems to customer's specifications and ensures high quality, reliability and
cost effectiveness.
 The Division has over 40 years of experience in producing aeronautical accessories making it
an ideal partner for the International Aero Engineering Industry.
The Division also manufactures and supplies complete range of components of Cheetah (Lama)
& Chetak (Alouette) Helicopters, Jaguar and MiG series Aircraft to Domestic and International
Customers to support their fleet.

30. Page 29


BASICS OF AIRCRAFT
Aerodynamics
Aerodynamics is derived from two Greek words - aero meaning air + dynamics meaning power.
It is a branch of dynamics concerned with studying the motion of air, particularly when it
interacts with a solid object, such as an airplane wing.
In other words, the science of aerodynamics deals with the motion of air and the forces acting on
bodies moving relative to the air. When we study aerodynamics, we are learning about why and
how an airplane flies. Although aerodynamics is a complex subject, exploring the fundamental
principles which govern flight can be an exciting and rewarding experience. The challenge to
understand what makes an airplane fly begins with learning the four forces of flight.
Four forces of flight
During flight, the four forces acting an the airplane are lift , weight , thrust and drag. Lift is the
upward force created by the effect of airflow as it passes over and under the wing. The airplane
is supported in flight by lift. Weight which opposes lift, is caused by the downward pull of
gravity. Thrust is the forward force which propels the airplane through the air. It varies with the
amount of engine power being used. Opposing thrust is drag, which is a backward or retarding,
force which limits the speed of the airplane. In un-accelerated flight, the four forces are in
equilibrium. Un-accelerated flight means that the airplane is maintaining a constant airspeed and
is neither accelerating nor decelerating.
In straight and-level , un-accelerated flight, lift is equal to the directly opposite weight and thrust
is equal to and directly opposite drag. Notice that the arrows which represent the opposing forces
are equal in length, but all four arrows are not the same length. This indicates that all four forces
are not equal but that the opposing forces are equal to each other.
The arrows which show the forces acting on an airplane are often called vectors. The magnitude
of a vector is indicated by the arrow’s length, while the direction is shown by the arrow’s

31. Page 30


orientation. When two or more forces act on an object at the same time, they combine to create a
resultant.
When vertical and horizontal forces are applied, as shown on the left, the resultant acts in a
diagonal direction. As shown on the right, the resultant of two opposing forces, which are equal
in magnitude, is zero.
Lift is the key aerodynamic force. It is the force which opposes weight. In straight-and-level, in-
accelerated flight, when weight and lift are equal, an airplane is in a state of equilibrium. If the
other aerodynamic factors remain constant, the airplane neither gains nor loses altitude.
When an airplane is stationary on the ramp, it is also in equilibrium, but the aerodynamic forces
are not a factor. In calm wind conditions, the atmosphere exerts equal pressure on the upper and
lower surfaces of the wing movement of air about the airplane, particularly the wing, is
necessary before the aerodynamic force of lift becomes effective. Knowledge of some of the
basic principles of motion will help you to understand the force of lift.

32. Page 31


PRINCIPLES INVOLVED
Newton’s Laws of Motion
In the 17th century, Sir Isaac Newton, a physicist and
mathematician presented principles of motion which, today; help to
explain in creation of lift by an airfoil. Newton’s three laws of
motion are as follows.
Newton’s first law : A body at rest tends to remain at rest, and a
body in motion tends to remain moving at the same speed and in
the same direction. For example, an airplane at rest on the ramp
will remain at rest unless a force is applied which is strong enough
to overcome the airplane’s inertia.
Newton’s second law: When a body is acted upon by a constant force, its resulting acceleration
is inversely proportional to the mass of the body and is directly proportional to the applied force.
This law may be expressed by the formula: [Force = mass x acceleration (F=ma)]
Newton’s third law : For every action there is an equal and opposite reaction. This principle
applies whenever two things act upon each other, such as the air and the propeller, or the air and
the wing of an airplane.
Bernoulli’s Principle
Daniel Bernoulli, a Swiss mathematician, expanded on Newton’s idea
and further explored the motion of fluids I his 1783 publication
Hydrodynamics. It was in this text that Bernoulli’s equation, which
describes the basic principle of airflow pressure differential, first
appeared. Bernoulli’s principle, simply stated, says, “as the velocity of
a fluid (air) increases, its internal pressure decreases.’ Bernoulli’s
principle is derived from Newton’s second law of motion which states

33. Page 32


the requirement of an in balanced force (in this case, pressure) to produce an acceleration
(velocity change).
One way we can visualize Bernoulli’s principles to imagine air flowing through a tube which is
narrower in the middle than at the ends. This type of device is usually called a venturi.
As the air enters the tube, it is traveling at a known velocity and pressure. When the airflow
enters the narrow portion, the velocity increases and the pressure decreases. Then, as the wider
portion, both the velocity and pressure return to their original values. Throughout this process,
the total energy of the air stream is conserved. An increase in velocity (kinetic energy) is
accompanied by a decrease in static pressure (potential energy).

34. Page 33


HOW LIFT IS GENERATED?
Lift is generated when an object changes the direction of flow of a fluid or when the fluid is
forced to move by the object passing through it. When the object and fluid move relative to each
other and the object turns the fluid flow in a direction perpendicular to that flow, the force
required to do this work creates an equal and opposite force that is lift.
The object may be moving through a stationary fluid, or the fluid may be flowing past a
stationary object—these two are effectively identical as, in principle, it is only the frame of
reference of the viewer which differs. The lift generated by an airfoil depends on such factors as:
 Speed of the airflow
 Density of the air
 Total area of the segment or airfoil
 Angle of attack (AOA) between the air and the airfoil
The AOA is the angle at which the airfoil meets the oncoming airflow (or vice versa). In the case
of a helicopter, the object is the rotor blade (airfoil) and the fluid is the air. Lift is produced when
a mass of air is deflected, and it always acts perpendicular to the resultant relative wind. A
symmetric airfoil must have a positive AOA to generate positive lift. At a zero AOA, no lift is
generated. At a negative AOA, negative lift is generated. A cambered or nonsymmetrical airfoil
may produce positive lift at zero, or even small negative AOA.
The basic concept of lift is simple. However, the details of how the relative movement of air and
airfoil interact to produce the turning action that generates lift are complex. In any case causing
lift, an angled flat plate, revolving cylinder, airfoil, etc., the flow meeting the leading edge of the
object is forced to split over and under the object. The sudden change in direction over the object
causes an area of low pressure to form behind the leading edge on the upper surface of the
object. In turn, due to this pressure gradient and the viscosity of the fluid, the flow over the
object is accelerated down along the upper surface of the object. At the same time, the flow
forced under the object is rapidly slowed or stagnated causing an area of high pressure. This also
causes the flow to accelerate along the upper surface of the object. The two sections of the fluid
each leave the trailing edge of the object with a downward component of momentum, producing
lift.

35. Page 34


Concept of Aerofoil
Aircrafts are able to fly due to aerodynamic forces produced when air passes around the airfoil.
An airfoil is any surface producing more lift than drag when passing through the air at a suitable
angle. Airfoils are most often associated with production of lift. Airfoils are also used for
stability (fin), control (elevator), and thrust or propulsion (propeller or rotor). Certain airfoils,
such as rotor blades, combine some of these functions. The main and tail rotor blades of the
helicopter are airfoils, and air is forced to pass around the blades by mechanically powered
rotation. In some conditions, parts of the fuselage, such as the vertical and horizontal stabilizers,
can become airfoils. Airfoils are carefully structured to accommodate a specific set of flight
characteristics.
Airfoil Terminology and Definitions
 Blade span—the length of the rotor blade from center of rotation to tip of the blade.
 Chord line—a straight line intersecting leading and trailing edges of the airfoil.
 Chord—the length of the chord line from leading edge to trailing edge; it is the characteristic
longitudinal dimension of the airfoil section.
 Mean camber line—a line drawn halfway between the upper and lower surfaces of the airfoil.
The chord line connects the ends of the mean camber line. Camber refers to curvature of the
airfoil and may be considered curvature of the mean camber line. The shape of the mean camber
is important for determining aerodynamic characteristics of an airfoil section.
Maximum camber (displacement of the mean camber line from the chord line) and its location
help to define the shape of the mean camber line. The location of maximum camber and its
displacement from the chord line are expressed as fractions or percentages of the basic chord
length. By varying the point of maximum camber, the manufacturer can tailor an airfoil for a
specific purpose. The profile thickness and thickness distribution are important properties of an
airfoil section.
 Leading edge—the front edge of an airfoil.
 Flightpath velocity—the speed and direction of the airfoil passing through the air. For airfoils
on an airplane, the flightpath velocity is equal to true airspeed (TAS). For helicopter rotor
blades, flightpath velocity is equal to rotational velocity, plus or minus a component of

36. Page 35

directional airspeed. The rotational velocity of the rotor blade is lowest closer to the hub and
increases outward towards the tip of the blade during rotation.
 Relative wind—defined as the airflow relative to an airfoil and is created by movement of an
airfoil through the air. This is rotational relative wind for rotary-wing aircraft and is covered
in detail later. As an induced airflow may modify flightpath velocity, relative wind
experienced by the airfoil may not be exactly opposite its direction of travel.
 Trailing edge—the rearmost edge of an airfoil.
 Induced flow—the downward flow of air through the rotor disk.
 Resultant relative wind—relative wind modified by induced flow.
 Angle of attack (AOA)—the angle measured between the resultant relative wind and chord
line.
 Angle of incidence (AOI)—the angle between the chord line of a blade and rotor hub. It is
usually referred to as blade pitch angle. For fixed airfoils, such as vertical fins or elevators,
angle of incidence is the angle between the chord line of the airfoil and a selected reference
plane of the helicopter.
 Center of pressure—the point along the chord line of an airfoil through which all
aerodynamic forces are considered to act. Since pressures vary on the surface of an airfoil, an
average location of pressure variation is needed. As the AOA changes, these pressures
change and center of pressure moves along the chord line.

37. Page 36


AXES OF ROTATION IN AN AIRCRAFT
An aircraft in flight is free to rotate in three dimensions: pitch, nose up or down about an axis
running from wing to wing, yaw, nose left or right about an axis running up and down; and roll,
rotation about an axis running from nose to tail. The axes are alternatively designated
as lateral, vertical, and longitudinal. These axes move with the vehicle, and rotate relative to the
Earth along with the craft. These rotations are produced by torques (or moments) about the
principal axes. On an aircraft, these are produced by means of moving control surfaces, which
vary the distribution of the net aerodynamic force about the vehicle's center of gravity. Elevators
(moving flaps on the horizontal tail) produce pitch, a rudder on the vertical tail produces yaw,
and ailerons (flaps on the wings which move in opposing directions) produce roll.
Principal axes
 Vertical axis, or yaw axis — an axis drawn from top to bottom, and perpendicular to the
other two axes. Parallel to the fuselage station.
 Lateral axis, transverse axis, or pitch axis — an axis running from the pilot's left to right in
piloted aircraft, and parallel to the wings of a winged aircraft. Parallel to the buttock line.
 Longitudinal axis, or roll axis — an axis drawn through the body of the vehicle from tail to
nose in the normal direction of flight, or the direction the pilot faces.
Vertical axis (yaw)
Yaw axis is a vertical axis through an aircraft, rocket, or similar body, about which the
body yaws; it may be a body, wind, or stability axis. Also known as yawing axis.
The yaw axis is defined to be perpendicular to the body of the wings with its origin at the center
of gravity and directed towards the bottom of the aircraft. A yaw motion is a movement of the
nose of the aircraft from side to side. The pitch axis is perpendicular to the yaw axis and is
parallel to the body of the wings with its origin at the center of gravity and directed towards the
right wing tip. A pitch motion is an up or down movement of the nose of the aircraft. The roll

38. Page 37


axis is perpendicular to the other two axes with its origin at the center of gravity, and is directed
towards the nose of the aircraft. A rolling motion is an up and down movement of the wing
tips of the aircraft. The rudder is the primary control of yaw.
Lateral axis (pitch)
The lateral axis (also called transverse axis) passes through the plane from wingtip to wingtips.
Rotation about this axis is called pitch. Pitch changes the vertical direction the aircraft's nose is
pointing. The elevators are the primary control of pitch.
Longitudinal axis (roll)
The longitudinal axis passes through the plane from nose to tail. Rotation about this axis is
called bank or roll. Bank changes the orientation of the aircraft's wings with respect to the
downward force of gravity. The pilot changes bank angle by increasing the lift on one wing and
decreasing it on the other. This differential lift causes bank rotation around the longitudinal axis.
The ailerons are the primary control of bank. The rudder also has a secondary effect on bank.

39. Page 38


STRUCTURE OF AN AIRCRAFT

40. Page 39


MAJOR COMPONENTS OF AIRCRAFT


Components and their functions

41. Page 40


1. Fuselage
The fuselage, or body of the airplane, is a long hollow tube which holds all the pieces of an
airplane together. The fuselage is hollow to reduce weight. As with most other parts of the
airplane, the shape of the fuselage is normally determined by the mission of the aircraft.
A supersonic fighter plane has a very slender, streamlined fuselage to reduce the drag associated
with high speed flight. An airliner has a wider fuselage to carry the maximum number of
passengers. On an airliner, the pilots sit in a cockpit at the front of the fuselage. Passengers and
cargo are carried in the rear of the fuselage and the fuel is usually stored in the wings. For a
fighter plane, the cockpit is normally on top of the fuselage, weapons are carried on the wings,
and the engines and fuel are placed at the rear of the fuselage.
The weight of an aircraft is distributed all along the aircraft. The fuselage, along with the
passengers and cargo, contribute a significant portion of the weight of an aircraft. The center of
gravity of the aircraft is the average location of the weight and it is usually located inside the
fuselage. In flight, the aircraft rotates around the center of gravity because of torques generated
by the elevator, rudder, and ailerons. The fuselage must be designed with enough strength to
withstand these torques.
2. Wings
Wings develop the major portion of the lift of a heavier-than-air aircraft. Wing structures carry
some of the heavier loads found in the aircraft structure. The particular design of a wing depends
on many factors, such as the size, weight, speed, rate of climb, and use of the aircraft. The wing
must be constructed so that it holds its aerodynamics shape under the extreme stresses of combat
maneuvers or wing loading. Wing construction is similar in most modern aircraft. In its simplest
form, the wing is a framework made up of spars and ribs and covered with metal.
Spars are the main structural members of the wing. They extend from the fuselage to the tip of
the wing. All the load carried by the wing is taken up by the spars. The spars are designed to
have great bending strength. Ribs give the wing section its shape, and they transmit the air load
from the wing covering to the spars. Ribs extend from the leading edge to the trailing edge of the

42. Page 41


wing. In addition to the main spars, some wings have a false spar to support the ailerons and
flaps. Most aircraft wings have a removable tip, which streamlines the outer end of the wing.
Most Navy aircraft are designed with a wing referred to as a wet wing. This term describes the
wing that is constructed so it can be used as a fuel cell. The wet wing is sealed with a fuel-
resistant compound as it is built. The wing holds fuel without the usual rubber cells or tanks. The
wings of most naval aircraft are of all metal, full cantilever construction. Often, they may be
folded for carrier use. A full cantilever wing structure is very strong. The wing can be fastened to
the fuselage without the use of external bracing, such as wires or struts.
A complete wing assembly consists of the surface providing lift for the support of the aircraft. It
also provides the necessary flight control surfaces.
Note: The flight control surfaces on a simple wing may include only ailerons and trailing edge
flaps. The more complex aircraft may have a variety of devices, such as leading edge flaps, slats,
spoilers, and speed brakes.
Various points on the wing are located by wing station numbers (fig. 4-7). Wing station (WS) 0
is located at the centerline of the fuselage, and all wing stations are measured (right or left) from
this point (in inches).
3. Empennage
The empennage is also known as the tail or tail assembly, of most aircraft, gives stability to the
aircraft, in a similar way to the feathers on an arrow; Most aircraft feature an empennage
incorporating vertical and horizontal stabilising surfaces which stabilise the flight
dynamics of yaw and pitch, as well as housing control surfaces.
In spite of effective control surfaces, many early aircraft that lacked a stabilising empennage
were virtually unflyable. Even so-called "tailless aircraft" usually have a tail fin (vertical
stabiliser). Heavier than air aircraft without any kind of empennage are rare.

43. Page 42


 Stabilizers
The stabilizing surfaces of an aircraft consist of vertical and horizontal airfoils. They are called
the vertical stabilizer (or fin) and horizontal stabilizer. These two airfoils, along with the rudder
and elevators, form the tail section. For inspection and maintenance purposes, the entire tail
section is considered a single unit called the empennage.
The main purpose of stabilizers is to keep the aircraft in straight-and-level flight. The vertical
stabilizer maintains the stability of he aircraft about its vertical axis (fig. 4-9). This is known as
directional stability. The vertical stabilizer usually serves as the base to which the rudder is
attached. The horizontal stabilizer provides stability of the aircraft about its lateral axis. This is
known as longitudinal stability. The horizontal stabilizer usually serves as the base to which the
elevators are attached. On many newer, high-performance aircraft, the entire vertical and/or
horizontal stabilizer is a movable airfoil. Without the movable airfoil, the flight control surfaces
would lose their effectiveness at extremely high altitudes.
Stabilizer construction is similar to wing construction. For greater strength, especially in the
thinner airfoil sections typical of trailing edges, a honeycomb-type construction is used. Some
larger carrier-type aircraft have vertical stabilizers that are folded hydraulically to aid aircraft
movement aboard aircraft carriers.
 Trim devices
In some aircraft trim devices are provided to eliminate the need for the pilot to maintain constant
pressure on the elevator or rudder controls.
The trim device may be:
 a trim tab on the rear of the elevators or rudder which act to change the aerodynamic load
on the surface. Usually controlled by a cockpit wheel or crank.

44. Page 43


 an adjustable stabiliser into which the stabiliser may be hinged at its spar and adjustably
jacked a few degrees in incidence either up or down. Usually controlled by a cockpit
crank.
 a bungee trim system which uses a spring to provide an adjustable preload in the controls.
Usually controlled by a cockpit lever.
 an anti-servo tab used to trim some elevators and stabilators as well as increased control
force feel. Usually controlled by a cockpit wheel or crank.
 a servo tab used to move the main control surface, as well as act as a trim tab. Usually
controlled by a cockpit wheel or crank.
Multi-engined aircraft often have trim tabs on the rudder to reduce the pilot effort required to
keep the aircraft straight in situations of asymmetrical thrust, such as single engine operations.
4. Powerplant
An aircraft engine is the component of the propulsion system for an aircraft that generates
mechanical power. Aircraft engines are almost always either lightweight piston engines or gas
turbines.
 Reciprocating engines
Most small airplanes are designed with reciprocating engines. The name is derived from the
back-and-forth, or reciprocating, movement of the pistons. It is this motion that produces the
mechanical energy needed to accomplish work. Two common means of classifying reciprocating
engines are:
1. by cylinder arrangement with respect to the crankshaft—radial, in-line, v-type or
opposed, or
2. by the method of cooling—liquid or air-cooled.

45. Page 44


Radial engines were widely used during World War II, and many are still in service today. With
these engines, a row or rows of cylinders are arranged in a circular pattern around the crankcase.
The main advantage of a radial engine is the favorable power-to-weight ratio.
In-line engines have a comparatively small frontal area, but their power-to-weight ratios are
relatively low. In addition, the rearmost cylinders of an air-cooled, in-line engine receive very
little cooling air, so these engines are normally limited to four or six cylinders.
V-type engines provide more horsepower than in-line engines and still retain a small frontal area.
Further improvements in engine design led to the development of the horizontally-opposed
engine.
Opposed-type engines are the most popular reciprocating engines used on small airplanes. These
engines always have an even number of cylinders, since a cylinder on one side of the crankcase
“opposes” a cylinder on the other side. The majority of these engines are air cooled and usually
are mounted in a horizontal position when installed on fixed-wing airplanes. Opposed-type
engines have high power-to-weight ratios because they have a comparatively small, lightweight
crankcase. In addition, the compact cylinder arrangement reduces the engine´s frontal area and
allows a streamlined installation that minimizes aerodynamic drag.
 Turboprop
While military fighters require very high speeds, many civil airplanes do not. Yet, civil aircraft
designers wanted to benefit from the high power and low maintenance that a gas turbine engine
offered. Thus was born the idea to mate a turbine engine to a
traditional propeller. Because gas turbines optimally spin at
high speed, a turboprop features a gearbox to lower the
speed of the shaft so that the propeller tips don't reach
supersonic speeds. Often the turbines that drive the propeller
are

46. Page 45


separate from the rest of the rotating components so that they can rotate at their own best speed
(referred to as a free-turbine engine). A turboprop is very efficient when operated within the
realm of cruise speeds it was designed for, which is typically 200 to 400 mph (320 to 640 km/h).
 Turboshaft
Turboshaft engines are used primarily for helicopters and auxiliary power units. A turboshaft
engine is similar in principle, but in a turboprop the
propeller is supported by the engine and the engine is bolted
to the airframe: in a turboshaft, the engine does not provide
any direct physical support to the helicopter's rotors. The
rotor is connected to a transmission which is bolted to the
airframe, and the turboshaft engine drives the transmission.
The distinction is seen by some as slim, as in some cases aircraft companies make both
turboprop and turboshaft engines based on the same design.
 Turbojet
A turbojet is a type of gas turbine engine that was originally developed for
military fighters during World War II. A turbojet is the simplest of all aircraft gas turbines. It
consists of a compressor to draw air in and compress it, a combustion section where fuel is added
and ignited, one or more turbines that extract power from the expanding exhaust gases to drive
the compressor, and an exhaust nozzle that accelerates the
exhaust gases out the back of the engine to create thrust.
When turbojets were introduced, the top speed of fighter
aircraft equipped with them was at least 100 miles per hour
faster than competing piston-driven aircraft. In the years
after the war, the drawbacks of the turbojet gradually
became apparent. Below about Mach 2, turbojets are very fuel inefficient and create tremendous
amounts of noise. Early designs also respond very slowly to power changes, a fact that killed
many experienced pilots when they attempted the transition to jets. These drawbacks eventually

47. Page 46


led to the downfall of the pure turbojet, and only a handful of types are still in production. The
last airliner that used turbojets was the Concorde, whose Mach 2 airspeed permitted the engine to
be highly efficient.
 Turbofan
A turbofan engine is much the same as a turbojet, but with an enlarged fan at the front that
provides thrust in much the same way as a ducted propeller, resulting in improved fuel-
efficiency. Though the fan creates thrust like a propeller, the
surrounding duct frees it from many of the restrictions that
limit propeller performance. This operation is a more
efficient way to provide thrust than simply using the jet
nozzle alone and turbofans are more efficient than propellers
in the trans-sonic range of aircraft speeds, and can operate in
the supersonic realm. A turbofan typically has extra turbine
stages to turn the fan. Turbofans were among the first engines to use multiple spools—concentric
shafts that are free to rotate at their own speed—to let the engine react more quickly to changing
power requirements. Turbofans are coarsely split into low-bypass and high-bypass categories.
Bypass air flows through the fan, but around the jet core, not mixing with fuel and burning. The
ratio of this air to the amount of air flowing through the engine core is the bypass ratio. Low-
bypass engines are preferred for military applications such as fighters due to high thrust-to-
weight ratio, while high-bypass engines are preferred for civil use for good fuel efficiency and
low noise. High-bypass turbofans are usually most efficient when the aircraft is traveling at 500
to 550 miles per hour (800 to 885 km/h), the cruise speed of most large airliners. Low-bypass
turbofans can reach supersonic speeds, though normally only when fitted with afterburners.
Landing Gears
Landing gear is the undercarriage of an aircraft or spacecraft and is often referred to as such.
For aircraft, the landing gear supports the craft when it is not flying, allowing it to take
off, land and usually to taxi without damage. Wheels are typically used but skids, skis, floats or a

48. Page 47


combination of these and other elements can be deployed depending both on the surface and on
whether the craft only operates vertically (VTOL) or is able to taxi along the surface. Faster
aircraft usually have retractable undercarriage, which folds away during flight to reduce air
resistance or drag.
For launch vehicles and spacecraft landers, the landing gear is typically designed to support the
vehicle only post-flight, and are not used for takeoff or surface movement.
Aircraft Flight Controls
 Primary controls
Generally, the primary cockpit flight controls are arranged as follows:
 a control yoke (also known as a control column), centre stick or side-stick (the latter two
also colloquially known as a control or joystick), governs the aircraft's roll and pitch by
moving the ailerons (or activating wing warping on some very early aircraft designs)
when turned or deflected left and right, and moves the elevators when moved backwards
or forwards
 rudder pedals, or the earlier, pre-1919 "rudder bar", to control yaw, which move
the rudder; left foot forward will move the rudder left for instance.
 throttle controls to control engine speed or thrust for powered aircraft.
The control yokes also vary greatly amongst aircraft. There are yokes where roll is controlled by
rotating the yoke clockwise/counterclockwise (like steering a car) and pitch is controlled by
tilting the control column towards you or away from you, but in others the pitch is controlled by
sliding the yoke into and out of the instrument panel (like most Cessnas, such as the 152 and
172), and in some the roll is controlled by sliding the whole yoke to the left and right (like the
Cessna 162).
Centre sticks also vary between aircraft. Some are directly connected to the control surfaces
using cables, others (fly-by-wire airplanes) have a computer in between which then controls the
electrical actuators.

49. Page 48


Even when an aircraft uses variant flight control surfaces such as a V-tail ruddervator, flaperons,
or elevons, to avoid pilot confusion the aircraft's flight control system will still be designed so
that the stick or yoke controls pitch and roll conventionally, as will the rudder pedals for
yaw.The basic pattern for modern flight controls was pioneered by French aviation figure Robert
Esnault-Pelterie, with fellow French aviator Louis Blériot popularizing Esnault-Pelterie's control
format initially on Louis' Blériot VIII monoplane in April 1908, and standardizing the format on
the July 1909 Channel-crossing Blériot XI. Flight control has long been taught in such fashion
for many decades, as popularized in ab initio instructional books such as the 1944 work Stick
and Rudder.
In some aircraft, the control surfaces are not manipulated with a linkage. In ultralight aircraft and
motorized hang gliders, for example, there is no mechanism at all. Instead, the pilot just grabs the
lifting surface by hand (using a rigid frame that hangs from its underside) and moves it.
 Secondary controls
In addition to the primary flight controls for roll, pitch, and yaw, there are often secondary
controls available to give the pilot finer control over flight or to ease the workload. The most
commonly available control is a wheel or other device to control elevator trim, so that the pilot
does not have to maintain constant backward or forward pressure to hold a specific
pitch attitude (other types of trim, for rudder and ailerons, are common on larger aircraft but may
also appear on smaller ones). Many aircraft have wing flaps, controlled by a switch or a
mechanical lever or in some cases are fully automatic by computer control, which alter the shape
of the wing for improved control at the slower speeds used for takeoff and landing. Other
secondary flight control systems may be available, including slats, spoilers, air
brakes and variable-sweep wings.

50. Page 49


CONCLUSION

 Finally we may conclude that HAL Accessories Division, Lucknow is a Government
undertaking, which is entitled to perform the making of the accessories used in the fighter
aircraft.
 Although the whole assembly of the aircraft is not done in HAL Lucknow but there are plans
to launch Sukhoi¶s full assembly in HAL Lucknow
 Thus HAL Lucknow would be entitled to work on latest technology of Sukhoi aircraft in the
coming future.

51. Page 50


REFERENCES

 Theoretical input in training centre.
 Interaction with professors in HAL
 http://www.av8n.com/how/
 http://www.hal-india.com/
 http://en.wikipedia.org/
 http://new.hal-india.com/
 http://www.grc.nasa.gov/
 http://www.free-online-private-pilot-ground-school.com/