This document provides an overview of jet engines, including their history, key parts, types, and comparisons to other propulsion systems. It discusses the main developers of the first jet engine in the early 1900s. The main types of jet engines are then outlined, including ramjet, turbojet, turbofan, turboprop, and turboshaft. Advantages of jet engines over internal combustion engines are higher mechanical efficiency and better weight to power ratios, while disadvantages include lower thermal efficiency and challenges with high temperature turbine blades. The document concludes with suggestions for future engine improvements and a vision of decreased aircraft weight enabling greater safety and flexibility.

1. JET ENGINES

2. CONTENTS
1. History of Jet Engines
2. Introduction
3. Parts Of Jet Engine
4. How A Jet Engine works
5. Types Of Jet Engine
 5.1 Ramjet
 5.2 Turbojet
 5.3 Turbofan
 5.4 Turboprop
 5.5 Turboshaft

3. CONTINUED . . .
6. Comparison Of Turbojets
7. Jet Engine Vs Rockets
8. Suggestion For Improvement
9. Merits And Demerits
10. Future Vision

4. 1.HISTORY OF JET ENGINES
 The first jet engine was built by
Egyptian scientists during 100 B.C
 These device was know as Aeolipile.
 Dr. Hans von Ohain and Sir Frank
Whittle were the main developers.

5. 2.INTRODUCTION
• Jet engine is nothing but a Gas turbine.
• It works under the principle of Newton’s third law
• It states that “For every acting force there is an equal
and opposite force”.
• Gas turbine operates like toy balloon

6. 3.PARTS OF JET ENGINE
 FAN
 COMPRESSOR
 COMBUSTOR
 TURBINE
 MIXER
 NOZZLE

7. 4.HOW A JET ENGINE WORKS ?
 Jet engines move the airplane forward with a great force that
is produced by a tremendous thrust and causes the plane to
fly very fast.

8. CONTINUED . . .
Air Intake
 sucked in by the compressor
Compressor
 series of vanes and stators.
 The vanes rotate, while the
stator remains stationary.
 compressor speed and
temperature increases
gradually
Fuel Burner
 Fuel is mixed with the air,
and electric sparks light the
air, causing it to combust.
Combustion Chamber
 The air is burnt.
 Increase in the temperature
of the air, thus increases the
pressure inside the engine.

9. 5. TYPES OF JET ENGINES
• Ramjet
• Turbojet
• Turbofan
• Turboprop
• Turbo shaft

10. 5.1 RAMJET
•It has no moving parts.
• Its compression ratio depends on
forward speed.
•It has no static thrust
• guided-missile systems, Space
vehicles use this type of jet

11. 5.2 TURBOJET
•The turbojet engine is a reaction
engine.
•Substantial increases in thrust can
be obtained by employing an
afterburner

12. 5.3 TURBOFAN
•The objective of this sort of bypass
system is to increase thrust without
increasing fuel consumption.
•It achieves this by increasing the total
air-mass flow and reducing the velocity
within the same total energy supply.

13. 5.4 TURBOPROP
•A turboprop engine is a jet engine
attached to a propeller.
.
•Modern turboprop engines are
equipped with propellers that have a
smaller diameter but a larger number
of blades for efficient operation at
much higher flight speeds

14. 5.5 TURBOSHAFT
 It does not drive a propeller.
 it provides power for a helicopter rotor.
 It permits the rotor speed to be kept
constant even when the speed of the
generator is varied

15. 6. COMPARISON WITH TURBOJETS
TURBOJET
RAMJETS
NO COMPRESSOR, TURBINE
LIGHT IN WEIGHT
MACH NO 2 TO 5
START ONLY AT MACH 2 AND ABOVE
 Has got compressor,
turbine
 Heavy
 Mach no. < 2
 Starts with zero initial
velocity

16. 7. JET ENGINES VS ROCKETS
Jet Engine Rockets
Oxygen from atmosphere for
combustion
Carry their own oxygen for
combustion
Work only in atmosphere Work in vacuum and atmosphere
Liquid fuel liquid or solid fuel
High Specific Impulse Low Specific Impulse
Complex Structure Simple Structure
High Efficiency Low Efficiency

17. 8. SUGGESTION FOR IMPROVEMENT
 Employ active cooling
 Designing better materials and alloys which retain their strength at high
temperatures
 Smart structures – Structure and material which change their shapes
and properties in flight.
 Design engines which switch from scramjets to ramjets.

18. 9. MERITS AND DEMERITS
Merits of Jet engine over
IC engine
 Mechanical efficiency
of jet engine is high as
compared to IC engine.
 Weight and speed of jet
engine per HP
developed is higher than
IC engine.
 Ignition and lubricating
systems are much
simpler in jet engine than
IC engine.
•Thermal efficiency of Jet engine is low
compared to IC engine
•Difficult to start
•Turbine blades need a special cooling
system due high temperature
Demerits Of Jet Engines Over
IC engine

19. 10. FUTURE VISION
Decreased gross lift – off weight
> Smaller facilities & easier handling
Leading to higher safety
Flights can be aborted, whiles the vehicle glides back to earth
Missions can be more flexible
Wider range of emergency landing sites for intact abort

20. THANK YOU