This document provides an overview of aviation principles. It discusses the history of flight from early concepts like kites to the Wright Brothers' first powered flight. It describes different types of aircraft as well as key flight control surfaces like wings, fins, and elevators. It also examines jet planes in detail, explaining components like the fan, compressor, combustor, turbine, and nozzle. Finally, it covers principles like Bernoulli's principle, different jet engine types, thrust, Mach number, and efficiency.

1. A SEMINAR REPORT
ON
PRINCIPLE OF Aviation
by
Sakti Prasad mishra
M.Sc. Applied Physics and Ballistics

2. CONTENTS
TOPIC
Introduction
History
Types of Air Craft
Jet Planes
Control Surface
Thrust Provider
Types of Jet Engines
Principles
Conclusion

3. INTRODUCTION
Aviation is the design, development, production,
operation, and use of aircraft especially heavier- than –air
aircraft. It is derived from the latten word “avis”, which
means bards. The human activity that surrounds the
aircraft called aviation.
An aircraft is a vehicle which is able to
fly by being supported by the air or in general, the
atmosphere of a planet. An air craft counters the force of
gravity by using either static lift or by using the dynamic
lift of an airfoil or in a few cases the downward thrust from
jet engines.

4. TYPES OF AIRCRAFTS
The aircrafts are manned aircraft i.e. those are flown by an onboard
pilot. Again unmanned aerial vehicles which are remotely controlled or self controlled by
onboard computers. Again aircraft can either be heavier-than-air or lighter- than –air.
The lighter than aircraft are like balloons and airships etc. and heavier than aircraft
including airplanes, autogiros, gliders, helicopters and ornithopters etc.
HISTORY
For centuries man has dreamed to soar with the birds. Famous inventors such
as Leonardo da Vinci, John String and Lawrence Hardgrave have conjured up ideas of
how to get some of the strangest machines to fly long before the Wright brothers.
The first form of an aircraft was the kite, designed in the 5th century
BC. Later on in the 13th century, Roger Bacon, an English monk, performed studies which
latter gave him the idea that air could support a craft just like water supports a boats. In
16th century, Leonardo da Vinci studied bird’s flight and latter produced the airscrew and
the parachute. The Wright brothers Orville and Wilbur were the two Americans who are
generally credited with inventing and building the world’s first successful air plane and
making the first controlled, powered and sustended heavier-than –air human flight on
17th December 1903.The first jet engine was made by a German physicist Hans Joachim
Von Ohian but sir Frank Whittles is known as the father of jet engine because turbojet
powered the Gloster E 28/39 which first flew in 1941.
Now consider Aviation with jet planes.

5. JET PLANES
Emission of a high speed fluid from a container through a narrow
opening by virtue of which the container can move in the opposite
direction called jet. The fundamental theory of jet propulsion is
Newton’s third law of motion.
A jet plane can be classified in to two major components.
(a)Control surface (b) Thrust provider

6. Flight Control Surface
Aircraft flight control surface allows a pilot to adjust and control the
aircraft’s flight altitude. The three major control surfaces are,
(a)Wing (b) Fin (c) Elevator
Wing
Wing plays an important role in flying of an aircraft; also its shape is
responsible for lifting and landing of the air plane. Even if we stop the engine
of the aero plane it can fly over some distances only due to the wing, because
wing gives stability to the plane. The wing is also placed that, unlike fin what
ever may be the forces acts on the wing it also act on the same way.
AILERON (FLAP)
The major component of the wing is responsible for giving up and downward
motion to the plane is its flap. Flaps are normally hinged surfaces mounted on
the trailing edges of the wings of a fixed-wing aircraft.
During takeoff just before leaving the run way the pilot bends the flap
downward and it separates the air in to two directions. One part of the air over
the wing which flows very faster and the other part below the wing which is
equal to atmospheric pressure. But the pressure of air is lowered above the
wing for which a pressure difference is created and due to this the plane gets
upward lift.During landing the reverse happens.

7. FIN
Fin is also an important component of an aero plane which is
responsible for changing the horizontal direction, i.e. to move
left or right. It also helps in maintaining balance.
Rudder is an important component of the fin which is
responsible for the changing of direction. It is a device to steer an
air craft that moves through the medium (air).Rudder is a flat
plane or sheet of material attached with hinges to the craft’s tail
or after end. These are shaped so as to minimize aerodynamic
drag.
ELEVATOR
An elevator is mounted on the trailing edge on each side of
the fin in the tail. They move up and down together. When the
pilot pulls the stick backward, the elevator goes up. Pushing the
stick forward causes the elevator to go down. Raised down
elevators push down on the tail and causeuse the nose to pitch
up. This makes the wings fly at a higher angle of attack.

8. YAW, PITCH AND ROLL
An aircraft in flight is free to rotate in the 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 pitch axis is perpendicular to the yaw axis and is parallel to the body of the
wings with its origin center at the center of gravity and directed towards the right
wing tip. Pitch changes the vertical direction of the aircraft’s nose.The elevators are
the primary control of pitch.
The yaw axis is defined to be perpendicular to the body of the wings with its origin
at the centre 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.Rudder is primary
control of yaw.
The roll axis is perpendicular to the pitch and yaw axes with its origin at the center
of gravity, and is directed towards the nose of the aircraft. Rotation of the axis is
called bank or roll .Bank changes the orientation of the aircraft’s wings with respect
to the downward gravity.The pilot changes the bank angle by increasing the lift on
one wing and decreasing it on the other.

9. THRUSTN PROVIDER
The engine provides the required thrust to the aero plane.
FAN
The fan is the first component whose blades are made with titanium like material. The large spinning fan
sucks in large quantities of air and then splits in to two parts. One part continues through the “core” or
centre of the jet engine and other part bypasses the jet engine which produces much of the force that
propels the airplane forward.
COMPRESSOR
The Compressor is the component in the jet engine core made up of fan with many blades and that
attached to a shaft. Compressor is generally two types.
Axial flow compressor
Axial compressor is rotating airfoil based in which the working fluid principally flows parallel to the axis
of rotation. Axial flow compressor produce a continuous flow of compressed gas and large mass flow
capacity, particularly in relation to their crossection.It can raise the air pressure to about 30 times that of
out side air.

10. Centrifugal compressor
It can squeeze the air by taking it near the centre of rapidly spinning wheel and then throwing
the air out towards the rim. The wheel of centrifugal compressor can not be arranging in rows
like axial flow compressor. It can raise the air pressure to about 6 times that of the out side air.
COMBUSTOR
Here the air is mixed with fuel and then ignited. There are as many as 20 nozzles to spray fuel into the airstream.
The mixture of air and fuel catches fire. This provides a high temperature, high energy flow. The fuel burns with
the oxygen in the compressed air, producing hot expanding gases. The inside of the combustor made with
ceramic materials to provide a heat resistant chamber. The heat can reach 27000F.

11. TURBINE
The high energy air flow coming out of the combustor goes in to the turbine causing the
turbine blades to rotate. The turbine is linked by a shaft to turn the blades in the compressor
and to spin the intake fan at the front. The gases produced in the combustion chamber move
through the turbine and spin its blades. The turbines of the jet spin around thousands of
times.
NOZZLE
The nozzle is the exhaust duct which produces the actual thrust. The energy depleted air flow that
passed the turbine, and the colder air that bypassed the engine core, produces a force when exiting
the nozzle that acts to propel the engine and thus the air plane moves forward.

12. PRINCIPLE APPLIED TO AERODYAMICS
Bernoulli’s Principle
Bernoulli’s principle is the principle that allows wings to produced lift for planes to fly. It works on the idea that
as a wing passes through the air .Its shape makes the air travel more over the top of the wing than beneath it. This
creates high pressure beneath the wing than above it. This pressure difference cause the wing to push upwards
and lift is created.
When the faster the wing moves through the air the more air is forced over and under the wing which creates
more lift. Again the amount of lift is also created due to the density of the air. The denser the air is the more lift is
produced. This is why planes climb in winter, the colder air is denser.
Types of jet engine
Turbo jet Engine
It’s very simple. Air taken in front of the engine is compressed to 3 to 12 times its original pressure in the
compressor. Fuel is added to the air and burned in a combustion chamber to raise the temperature of the fluid
mixture to about 11000F to 13000F.The resulting hot air is passed through the turbine, which drives the
compressor.

13. Turbo fan Engine
It has a large fan at front which sucks in air. Most of the air flows around the outside of the engine making
it quieter and giving it more thrust at the low speed.
Turbo shaft Engine
This is the another form of gas turbine engine which the rotor speed to be kept constant even when the speed of the
generator is varied to modulate the amount of power produced. It is designed so that the speed of the helicopter rotor is
independent of the gas generator.
Turboprops Engine
This is the jet engine that attached to a propeller. The turbine at the back is turned by the hot gases, and
this turns a shaft that drives the propeller. Some small airlines and transport aircraft are powered by
turboprops.
Ramjet Engine
The simplest jet engine Ha no moving parts .The speed of the jet engine “rams “or forces air in to the engine .Its essentially a
turbojet in which rotating machinery has been omitted. Space vehicles use this type of jet. A ramjet engine provides a
simple, light propulsion system for high speed flight.

14. Thrust
Thrust is the force which moves any aircraft through the air. Thrust is generated by the propulsion
system of the aircraft. Different propulsion systems develop thrust in different ways, but all thrust is
generated through some application of Newton’s third law of motion. For every action there is an
equal and opposite reaction.
Thrust supplied by jet
Thrust supplied by the jet. Let us now calculate the thrust supplied to an aircraft by the jet produced by
the power-unit inside it.
Suppose we have an aircraft travelling with a speed ‘v’ and fitted with a power-unit which produces a
jet of fluid, of velocity ‘v’ relatives to the aircraft, where ‘u’ is higher than ‘v’, the velocity ‘u’ of the jet
being measured at a point in it a little away from the nozzle, where the static pressure is the same as
that in the surrounding air. Then, if we impose a velocity ‘v’ on the aircraft in the opposite direction
to its own, the aircraft comes to rest, with the air streaming past it with velocity ‘v’. So that, if ‘a’ be
the area of cross-section of the jet at the point where its velocity is ‘u’, the volume of the fluid
flowing per second in the jet is dearly (a.u). If, therefore, ‘ρ’ be the density of the fluid, we have,
Mass-flow of the fluid per second in the jet=a.u.ρ=m (say).
And, therefore, momentum of this fluid in the jet=m.u.
If this mass ‘m’ of the fluid finally emerges out from the aircraft with a velocity ‘v’, its momentum is
clearly reduced to “mv”. It thus suffers a loss of momentum, equal to (mu-mv) or m (u-v) per
second, i.e. , its rate of change of momentum = m (u-v).
Therefore in accordance with Newton’s second law of motion, must be the force or the thrust F
supplied to the aircraft by the jet in the direction of opposite. So that,
F = m (u-v) = a.u.ρ. (u-v).

15. Efficiency of the jet
Let the aircraft is moving with velocity v , then the velocity of the final jet ,
moving in the opposite direction , clearly becomes (u-v) and therefore,
Kinetic Energy of the final jet = 2 = .
Again the aircraft does Fv amount of work per second against the air resistance
as it moves forwards. So that total energy that supplied by the power unit =
Thus the efficiency of the jet is defined as
The efficiency will be maximum value 1, when (u-v), i.e. when the initial jet
velocity is equal to the flight velocity of the aircraft for then, the energy wasted
in the form of the final jet i.e. will become zero.

16. MACH NUMBER
The ratio of the speed of the aircraft to the speed of the sound in the gas determines the
magnitude of the compressibility effect. This ratio in aerodynamics is designated with
the special parameter called the Mach number in honor of the 19th century physicist
Ernst Mach. This Mach number is denoted by ‘M’.
The space shuttle may re enters the atmosphere at which
hypersonic speed of Mach value M ~ 25.The Mach number
depends on the speed of sound in the gas and the speed of sound
depends on the type of gas and the temperature of the gas.
Low
subsonic
subsonic Transonic Supersonic Highsupersonic Hypersonic
M<< 1 M<1 M=1 1<M<3 3<M<5 M>5

17. CONCLUSION
Aircrafts are most sophisticated and costly products of the
modern age. These vehicles are used in many fields such as
transport, war and in other fields. In future there will be
many other types of propulsion methods which will make
these machines more costly, powerful and technologically
advanced. The most important thing is that these
machines can be used both for the welfare and destruction
of mankind. So if these powerful machines are used for the
welfare of mankind then the future generation will be safe
and more advanced.