This document is a seminar report on aeroplane propulsion systems presented by two students, Saurav Kumar and Sawan Kumar, to fulfill the requirements of their mechanical engineering course. The report includes sections on the different types of propulsion systems used in aeroplanes such as jet, rocket, and propeller propulsion. It discusses the key components that enable these different propulsion methods, such as the air intake, combustion chamber, turbine, and nozzle. The report provides an overview of aeroplane propulsion systems for educational purposes.

1. Seminar Report on
Aeroplane Propulsion System
Presented by
Saurav Kumar (16900714087)
Sawan Kumar (16900714088)
2016
Department of Mechanical Engineering
Academy of Technology
Adisaptagram, Hooghly, West Bengal
India – 712121.

2. Certificate
This is certify that the work presented in this Seminar
Report has been prepared by Saurav Kumar____________
(Roll No. 16900714087) and Sawan Kumar_____________
(Roll No. 16900714088) being Fifth Semester B.Tech
Mechanical Engineering students of AOT,
Adisaptagram.
……………………….. ………….………….
Sourav Kayal Amit Kumar Rana
(Mentor) (Head of Department)
Examined by:
………………………… …………………………
………………………… …………………………
(i)

3. Statement by the Candidate
We hereby state that this technical report has been prepared by us
is a record of our presentation on this topic. The report is being
submitted to fulfill the requirements of course ME-581 of the
curriculum of Academy of Technology, Adisaptagram, Hooghly, India
712121.
……………………………. …….……………………
Saurav Kumar Sawan Kumar
( 87/ 5th /ME) ( 88/ 5th /ME)
(II)

4. ABSTRACT
A heavier than any flying machine, supported by aerofoils, designed
to obtain, when driven through the air at an angle inclined to the
direction if motion, a reaction from the air approximately at right
angle to their surface is known as areoplane. The various force
which acts on the aeroplane when it travels through the air lift force,
drag force, thrust force and its own weight. For steady condition the
weight should be balanced by the lift and drag by thrust.
The lift is obtained due to the special shape of wings and thrust is
obtained by propulsion systems.
The main objective of this seminar are to describe the different
engines used for jet propulsion and the future scope of propulsion
systems.
(III)

5. ACKNOWLEDGEMENT
We express our sincere thanks to our mentor Prof. Sourav Kayal,
Assistant-Professor, Mechanical Engineering Department,
Academy of Technology, West Bengal for guiding us from the
starting to till the Successful completion. We sincerely acknowledge
him for extending his valuable guidance, support for literature,
Critical reviews of seminar report and above all the moral support
that he had provided to us with all stages of seminar.
Finally, we would also like to add few heartfelt words for the people
who where the part of the seminar in various ways, especially our
friends and classmates who gave us unending support right from the
beginning. Our family has been the most significant in our life so far
and this part of our life has no exception. Without their support,
persistence and love we would not be where we are today.
Saurav Kumar Sawan Kumar
(3rd Year, 5th Sem..) (3rd Year, 5th Sem…)
Academy of Technology, Academy of Technology,
West Bengal, India. West Bengal, India.
(IV)

6. CONTENTS
Certificate (I)
Endorsement (II)
Abstract (III)
Acknowledgement (IV)
Introduction (1)
Working Principle (2)
Design of Aircraft (3)
Safety and Manufacturing (4-5)
Propulsion System (6-7)
Aircraft Motion (8)
Aeroplane Engine (9)
The Air Intake (10)
Jet Propulsion (11)
Rocket Propulsion (12-13)
Propeller Propulsion (14)
Motion of Propeller (14)
The Compressor (15)
Advantages of Jet Propulsion (16)
Advantages of Rocket Propulsion (16)
The combustion chamber (17)
Turbine and The outlet (18)
Conclusion (19)
References (20)

7. INTRODUCTION
AIRCRAFT is a machine that is able to fly by gaining support from the air. It
counters the force of gravity by using either static lift or by using the dynamic lift
of an air foil, or in a few cases the downward thrust from jet engines.
The human activity that surrounds aircraft is called aviation. Crewed aircraft are
flown by an on-board pilot, but unmanned aerial vehicles may be remotely
controlled or self-controlled by on-board computers. Aircraft may be classified by
different criteria, such as lift type, aircraft propulsion, usage and others.
PROPULSION is a means of creating force leading to movement. The
term is derived from two Latin words: pro, meaning before or forward; and
pellere, meaning to drive. A propulsion system consists of a source of mechanical
power, and a propulsor (means of converting this power into propulsive force).
A technological system uses an engine or motor as the power source, and wheels
and axles, propellers, or a propulsive nozzle to generate the force. Components
such as clutches or gearboxes may be needed to connect the motor to axles,
wheels, or propellers.
Biological propulsion systems use an animal's muscles as the power source, and
limbs such as wings, fins or legs as the propulsors.
Some aircraft, like airliners and cargo planes, spend most of their life in a cruise
condition. For these airplanes, excess thrust is not as important as high engine
efficiency and low fuel usage. Since thrust depends on both the amount of gas
moved and the velocity, we can generate high thrust by accelerating a large mass
of gas by a small amount, or by accelerating a small mass of gas by a large
amount. Because of the aerodynamic efficiency of propellers and fans, it is more
fuel efficient to accelerate a large mass by a small amount. That is why we find
high bypass fans and turboprops on cargo planes and airliners.
(1)

8. WORKING PRINCIPLE
This simplified diagram shows you
the process through which a jet
engine converts the energy in fuel
into kinetic energy that makes a plane
soar through the air.
 A fan at the front sucks the
cold air into the engine and
forces it through the inlet. This slows the air down by about 60 percent and
its speed is now about 400 km/h (240 mph).
 A second fan called a compressor squeezes the air (increases its
pressure) by about eight times, and this dramatically increases its
temperature.
 Kerosene (liquid fuel) is squirted into the engine from a fuel tank in the
plane's wing.
 In the combustion chamber, just behind the compressor, the kerosene
mixes with the compressed air and burns fiercely, giving off hot exhaust
gases and producing a huge increase in temperature. The burning mixture
reaches a temperature of around 900°C (1650°F)
.
 The exhaust gases rush past a set of turbine blades, spinning them like a
windmill. Since the turbine gains energy, the gases must lose the same
amount of energy—and they do so by cooling down slightly and losing
pressure.
 So the hot air leaving the engine at the back is traveling over twice the
speed of the cold air entering it at the front—and that's what powers the
plane.
(2)

9. In brief, you can see that each main part of the engine does a different thing to the air or
fuel mixture passing through:
 Compressor: Dramatically increases the pressure of the air (and, to a lesser
extent) its temperature.
 Combustion chamber: Dramatically increases the temperature of the air-
fuel mixture by releasing heat energy from the fuel.
 Exhaust nozzle: Dramatically increases the velocity of the exhaust gases, so
powering the plane.
DESIGN OF AIRCRAFT
PURPOSE : The design process starts with the aircraft's intended purpose.
Commercial airliners are designed for carrying a passenger or cargo payload, long
range and greater fuel efficiency where as fighter jets are designed to perform high
speed maneuvers and provide close support to ground troops.
Financial factors and market :
Budget limitations, market requirements and competition set constraints on the design
process and comprise the non-technical influences on aircraft design along with
environmental factors. Competition leads to companies striving for better efficiency in
the design without compromising performance and incorporating new techniques and
technology.
Environmental factors:
An increase in the number of aircraft also means greater carbon emissions.
Environmental scientists have voiced concern over the main kinds of pollution
associated with aircraft, mainly noise and emissions. Aircraft engines have been
historically notorious for creating noise pollution and the expansion of airways over
already congested and polluted cities have drawn heavy criticism, making it necessary
to have environmental policies for aircraft noise. Noise also arises from the airframe,
where the airflow directions are changed.Improved noise regulations have forced
designers to create quieter engines and airframes. Emissions from aircraft include
particulates, CO2, SO2, CO, various oxides of nitrates and unburnt hydrocarbons.
(3)

10. Safety and manufacturing
The high speeds, fuel tanks, atmospheric conditions at cruise altitudes, natural hazards
(thunderstorms, hail and bird strikes) and human error are some of the many hazards
that pose a threat to air travel.
Airworthiness is the standard by which aircraft are determined fit to fly.The responsibility
for airworthiness lies with national aviation regulatory bodies, manufacturers, as well as
owners and operators.
The aircraft manufacturer makes sure that the aircraft meets existing design standards,
defines the operating limitations and maintenance schedules and provides support and
maintenance throughout the operational life of the aircraft. The aviation operators
include the passenger and cargo airliners, air forces and owners of private aircraft. They
agree to comply with the regulations set by the regulatory bodies, understand the
limitations of the aircraft as specified by the manufacturer, report defects and assist the
manufacturers in keeping up the airworthiness standards.
The interior of the cabin is also fitted with safety features such as oxygen masks that
drop down in the event of loss of cabin pressure, lockable luggage compartments,
safety belts, lifejackets, emergency doors and luminous floor strips
Design aspects
Propulsion
Aircraft propulsion may be achieved by specially designed aircraft, adapted auto,
motorcycle or snowmobile engines, electric engines or even human muscle power. The
main parameters of engine design are:
 Maximum engine thrust available
 Fuel consumption
 Engine mass
 Engine geometry
The thrust provided by the engine must balance the drag at cruise speed and be greater
than the drag to allow acceleration. The engine requirement varies with the type of
aircraft. For instance, commercial airliners spend more time in cruise speed and need
more engine efficiency. High-performance fighter jets need very high acceleration and
therefore have very high thrust requirements.
(4)

11. Weight
The weight of the aircraft is the common factor that links all aspects of aircraft design
such as aerodynamics, structure, and propulsion together. An aircraft's weight is
derived from various factors such as empty weight, payload, useful load, etc. The
various weights are used to then calculate the center of mass of the entire aircraft.The
center of mass must fit within the established limits set by the manufacturer.
Structure
The aircraft structure focuses not only on strength, stiffness, durability (fatigue), fracture
toughness, stability, but also on fail-safety, corrosion resistance, maintainability and
ease of manufacturing. The structure must be able to withstand the stresses caused
by cabin pressurization, if fitted, turbulence and engine or rotor vibrations.
(5)

12. Propulsion System
Propulsion is a means of creating force leading to movement. The term is derived from
two Latin words: pro, meaning before or forward; and puller, meaning to drive. A
propulsion system consists of a source of mechanical power, and a propulsor (means of
converting this power into propulsive force).
An aircraft propulsion system generally consists of an aircraft engine and some means
to generate thrust, such as a propeller or a propulsive nozzle.
An aircraft propulsion system must achieve two things. First, the thrust from the
propulsion system must balance the drag of the airplane when the airplane is cruising.
And second, the thrust from the propulsion system must exceed the drag of the airplane
for the airplane to accelerate.
In fact, the greater the difference between the thrust and the drag, called the excess
thrust, the faster the airplane will accelerate. Some aircraft, like airliners and cargo
planes, spend most of their life in a cruise condition. For these airplanes, excess thrust
is not as important as high engine efficiency and low fuel usage. Since thrust depends
on both the amount of gas moved and the velocity, we can generate high thrust by
accelerating a large mass of gas by a small amount, or by accelerating a small mass of
gas by a large amount. Because of the aerodynamic efficiency of propellers and fans, it
is more fuel efficient to accelerate a large mass by a small amount. That is why we find
high bypass fans and turboprops on cargo planes and airliners.
(6)

13. A propeller or airscrew comprises a set of small, wing-like aerofoil blades set around a
central hub which spins on an axis aligned in the direction of travel. The blades are set
at a pitch angle to the airflow, which may be fixed or variable, such that spinning the
propeller creates aerodynamic lift, or thrust, in a forward direction.
A tractor design mounts the propeller in front of the power source, while a pusher
design mounts it behind. Although the pusher design allows cleaner airflow over the
wing, tractor configuration is more common because it allows cleaner airflow to the
propeller and provides a better weight distribution.
(7)

14. Aircraft Motion
If the forces become unbalanced, the aircraft will move in the direction of the greater
force. We can compute the acceleration which the aircraft will experience from Newton's
second law of motion
F = m * a
Where a is the acceleration, m is the mass of the aircraft, and F is the net force acting
on the aircraft. The net force is the difference between the opposing forces; lift minus
weight, or thrust minus drag
If the weight is decreased while the lift is held constant, the airplane will rise:
Lift > Weight - Aircraft Rises
If the lift is decreased while the weight is constant, the plane will fall:
Weight > Lift - Aircraft Falls
Similarly, increasing the thrust while the drag is
constant will cause the plane to accelerate:
Thrust > Drag - Aircraft Accelerates
And increasing the drag at a constant thrust will
cause the plane to slow down:
Drag > Thrust - Aircraft Slows
(8)

15. AEROPLANE ENGINE
The engine is thus an energy transformer. Energy (also
called work, and quantified in Joules) can itself be
interpreted as a force in motion. In the well-known case
of a car engine, the thermal energy coming from the 20
combustion of petrol and air is transformed into
mechanical energy which is applied to the wheels of the
vehicle (the force allowing to turn the wheels).
The efficiency is defined as the ratio between the result
obtained (the mechanical energy transmitted to the
wheels in the example of a car engine) and the means
used to produce it (thermal energy contained in the petrol-air mixture in this example).
Its value is always less than 1 (or 100%).
In flight, an aircraft does not have wheels in contact with the ground The principle of
aeronautical propulsion is a direct application of Newton‘s third law of motion (principle
of opposite action or action-reaction. In the case of aeronautical propulsion, the body A
is atmospheric air which is accelerated through the engine. The force – the action –
necessary to accelerate this air has an equal effect, but in the opposite direction – the
reaction -, applied to the object producing this acceleration (the body B, that is the
engine, and hence the aircraft to which it is attached).
It is possible to imagine much simpler examples based on the same principle. The first,
probably the most simple, is that of the fairground balloon, which is first inflated then
released. The air (body A) is ejected from the balloon (body B) through a small opening
and at high speed. The balloon is propelled in the opposite direction to the ejected air –
this is the reaction. The second example is that of a rotating watering system. The
speed of water (body A) is increased by its passage through small ejection holes. The
two arms of the watering.
(9)

16. THE AIR INTAKE
The air intake is one of the most visible parts of an aircraft engine. A typical photo of this
component is shown on the right picture. This envelope which precedes the main part of
the engine is attached to a strut, which is itself fixed to a wing or the fuselage. The main
purposes of this nacelle are:
to present as little air resistance (drag) as possible
 to guarantee optimal functioning of the engine during
the different phases of flight (take-off, cruise, landing)
 to limit the acoustical disturbance of the engine by absorbing some of the noise
 to protect the inlet parts of the engine from phenomena relating to icing (the local
temperature at 10 000 metres altitude is between -40° and -50°C)
(10)

17. JET PROPULSION
Jet propulsion is thrust produced by passing a jet of matter (typically air or water) in
the opposite direction to the direction of motion. By Newton's third law, the moving body
is propelled in the opposite direction to the jet. It is most commonly used in the jet
engine, but is also the favoured means of propulsion used to power various space craft.
A number of animals, including cephalopods sea hares, arthropods, and fish have
convergently evolved jet propulsion mechanisms.
Jet propulsion is most effective when the Reynolds number is high - that is, the object
being propelled is relatively large and passing through a low-viscosity medium.
.
A jet engine is a reaction engine that discharges a fast moving jet of fluid to generate
thrust by jet propulsion and in accordance with Newton's laws of motion. This broad
definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets and
pump-jets.
(11)

18. ROCKET PROPULSION
A rocket engine is a type of jet engine that uses
only stored rocket propellant mass for forming its
high speed propulsive jet. Rocket engines are
reaction engines, obtaining thrust in accordance
with Newton's third law. Most rocket engines are
internal combustion engines, although non-
combusting forms (such as cold gas thrusters) also
exist. Vehicles propelled by rocket engines are
commonly called rockets. Since they need no
external material to form their jet, rocket engines
can perform in a vacuum and thus can be used to
propel spacecraft and ballistic missiles.
Rocket engines as a group have the highest thrust,
are by far the lightest, but are the least propellant
efficient (have the lowest specific impulse) of all
types of jet engines. The ideal exhaust is hydrogen,
the lightest of all gases, but chemical rockets
produce a mix of heavier species, reducing the
exhaust velocity. Rocket engines become more
efficient at high velocities (due to greater propulsive
efficiency and Oberth effect). Since they do not
benefit from, or use, air, they are well suited for uses
in space and the high atmosphere.
The nozzle uses the heat energy released by
expansion of the gas to accelerate the exhaust to
very high (supersonic) speed, and the reaction to
this pushes the engine in the opposite direction.
Rocket propellant is mass that is stored, usually in
some form of propellant tank, prior to being ejected
from a rocket engine in the form of a fluid jet to
produce thrust.
(12)

19. Chemical rocket propellants are most commonly used, which undergo exothermic
chemical reactions which produce hot gas which is used by a rocket for propulsive
purposes. Alternatively, a chemically inert reaction mass can be heated using a high-
energy power source via a heat exchanger, and then no combustion chamber is used.
Solid rocket propellants are prepared as a mixture of fuel and oxidising components
called 'grain' and the propellant storage casing effectively becomes the combustion
chamber. Liquid-fuelled rockets typically pump separate fuel and oxidizer components
into the combustion chamber, where they mix and burn. Hybrid rocket engines use a
combination of solid and liquid or gaseous propellants. Both liquid and hybrid rockets
use injectors to introduce the propellant into the chamber. These are often an array of
simple jets - holes through which the propellant escapes under pressure; but sometimes
may be more complex spray nozzles. When two or more propellants are injected, the
jets usually deliberately cause the propellants to collide as this breaks up the flow into
smaller droplets that burn more easily.
(13)

20. PROPELLER PROPULSION
A piston engine requires a propeller to convert the power output of the engine in to
thrust. The power is developed by the piston engine, and is transmitted to the propeller,
via a shaft, as engine torque or turning effect. This is used to rotate the propeller, which
converts most of the turning effect in to a pull or push force, called thrust. The propeller
does this by generating forces which result from its motion through air.
The propeller pulls the aeroplane through the air by generating a basically ‗lift‘ force
which we call thrust. The propeller blade is so fitted that its curved face is always at the
front side of the plane. Thus the propeller blade causes the air to flow so that the static
pressure ahead of the blade is less than that behind the blade. The result is a forward
thrust force on the propeller blade which pulls the aeroplane along.
Motion of the Propeller
When the aeroplane is moving forward, the propeller
will have two different motions.
1. Forward motion
2. Rotational motion
(14)

21. THE COMPRESSOR
The compressor, situated just behind the air
intake, is the first element which allows
transformation of energy, in this case from
mechanical energy into energy in the form of
pressure. This machine is presented at the bottom
left, where the flow is from left to right.
The compressor is composed of a series of fixed
blades, both fixed (stators – coloured in grey in the
figure) and moving (rotors – coloured in blue,
yellow and red in the figure). The function of these
blades is to transform the mechanical energy
which turns the rotors into pressure energy. This
transformation operates by directing in a precise
way the flow which develops in the channels
defined by the blades and the envelope of the
engine. The blades turns at a rotating speed of
5000 revolution per minute. The diameter of
blades is order of 3.25 meters and the length is
order of 1.20 meter.
(15)

22. ADVANTAGES OF JET PROPULSION
Simply a much higher thrust to weight ratio vs a piston/propeller combination. Also at
higher altitudes, the jet can produce thrust needed without supercharging. The turbine
blades act as a huge vacuum cleaner and they do their own "supercharging" of the air.
Piston/propeller combinations need a separate supercharger to get enough air into the
engine.
At low altitudes, jet propulsion are fuel hogs but are more fuel efficient at high altitudes.
Piston/propeller engines can take advantage of the more dense air at low altitudes -
more efficient..
ADVANTAGES OF ROCKET PROPELLANTS
Solid propellants are the most versatile of all. They do not require any engine
for combustion but once ignited, the combustion can't be stopped in between.
They just need a cylindrical casing for storage.
The conventional solid propellants provide lesser thrust than their liquid
counterpart.
Liquid propellants are difficult to handle and require separate storage tanks.
They demand a complex engine with pumps and turbo-compressors for
combustion but they have an advantage of providing a relatively higher thrust
than solid propellants.
(16)

23. THE COMBUSTION CHAMBER
The combustion chamber, situated just downstream from the compressor, is the
element in which thermal energy is added to the pressure energy accumulated at the
outlet of the compressor. The transformation of energy considered here comes from the
combustion of the air mixture /kerosene (the combustible used in most aircraft engines)
which generates an increase in the temperature of the air passing through the engine.
Calculations show that the efficiency of the engine will be better if the temperature at the
outlet of the combustion chamber is higher. In the most recent engines, temperatures of
the order of 2100°C are achieved. The materials used for the construction of a
combustion chamber contain an important fraction of nickel and chrome. The melting
temperature of these two metals is less than this 2100°C and protection and cooling of
the metal parts is therefore absolutely necessary.
(17)

24. TURBINE
The turbine is situated at the outlet of the combustion chamber. Its function is to
transform the energy available in the form of pressure and temperature into mechanical
energy. In other words, the turbine is the ―motor‖ which turns the compressor. The
pressure and temperature of the air kerosene mixture will decrease during passage
through this element.
As for the compressor, the turbine is composed of a series of blades, both fixed
(stators) and moving (rotors). The function of these rotors is to transform the
temperature and pressure energy into mechanical energy which turns the compressor.
As an example rotor is generally composed of 30 to 40 blades
Calculations show that the complete transformation of the energy available in the form
of pressure and temperature and the energy available in the kerosene gives more
mechanical energy than is needed to turn the compressor (typically twice as much). The
turbine serves then to transform only the quantity of energy strictly required to achieve
this function
THE OUTLET
This last element, situated at the back of the turbine, is the outlet tube. In this tube the
last transformation of energy takes place with the aim of creating a jet of air exiting the
engine at high speed, thus allowing the propulsion of
the aircraft according to the principle of
action/reaction. This transformation is achieved by a
controlled variation of the cross-section of the outlet
tube.
In the case of Concorde (a now discontinued
supersonic civil transport aircraft) and in the case of
a number of military aircrafts, a final transformation
of energy, afterburning, is made in the outlet tube.
The principle of this transformation is to inject extra
kerosene and burning the mixture. The extra energy
obtained gives an even higher
speed to the jet of air exiting the engine and hence
an even great propulsive power. A photo of the
outlet jet, with after burn shown in fig. This
technology is mainly used for aircraft flying at
speeds greater than the speed of sound.
(18)

25. Conclusion
A propulsion system is a machine that produces thrust to push an
object forward. On airplanes, thrust is usually generated through
some application of Newton's third law of action and reaction. A
gas, or working fluid, is accelerated by the engine, and the
reaction to this acceleration produces a force on the engine.
The four basic parts of a jet engine are the compressor, turbine,
combustion chamber, and propelling nozzles. Air is compressed, then
led through chambers where its volume is increased by the heat of fuel
combustion. On emergence it spins the compression rotors, which in
turn act on the incoming air.
(19)

26. References:
 https://en.wikipedia.org/wiki/Propulsion
 textofvideo.nptel.iitm.ac.in/101101001/lec1.pdf by Pk Nag.
 https://en.wikipedia.org/wiki/Combustion_chamber
 https://en.wikipedia.org/wiki/Aircraft_engine
 http://www.airspacemag.com/flight-today/inside-boeings-
787-factory-94818438/?no-ist
(20)