Focuses more about the Helicopter propulsion

2. DEFINITION

3. AIRCRAFT
A machine that is able to fly by
gaining support from the air.

4. PROPULSION
The word is derived from two Latin
words: pro meaning before or forwards and
pellere meaning to drive.
Propulsion means to push forward or drive an
object forward.

5. AIRCRAFT PROPULSION
 Lift – the force the causes an aircraft to
overcome gravity, climb into the air and stay in
the air.
Weight – the force generated by the
gravitational attraction of the earth on
the aircraft.
 Thrust – the force which moves an aircraft
through the air.
 Drag - forces acting opposite to the relative
motion of any object moving.

7. EXAMPLES OF AIRCRAFT

8. AIRPLANE

9. TRIVIA
 It is a Boeing VC-25, a military
version of Boeing 747.
 A plane can only use the call sign
“Air Force One” if it is a military
aircraft attached to the 89th Air Lift
Wing and only when the President
of the United States is on board.

10. HOT AIR BALLOON

11. TRIVIA
 The first human carrying flight
technology.
 The large balloon on top is called an
“envelope”. It holds hot air created by a
heat source known as a burner.
 Hot air balloons can fly to amazing
heights, the world record is over
21,000 meters.

12. AIRSHIP

13. TRIVIA
 Also called as Blimps
 These airships are filled with helium.
The helium is maintained under
low pressure.
 Goodyear Blimps uses this for
advertising purposes and for use as
a television camera platform for aerial
views of sporting events.

14. SEAPLANES

15. TRIVIA
 Powered fixed-wing aircraft capable
of taking off and landing on water.
 Motor-powered watercraft which
uses hydrofoils to levitate their main
hull above the water when running
at a speed.

16. HELICOPTER

17. HISTORY
The earliest known mention of a rotor-powered
flying machine appears in a Chinese
text written about A.D. 320. The design of this
machine may have been based on a Chinese
toy called the flying top. Such toys flew by
means of feather rotors. In 1483, Leonardo da
Vinci sketched a design for a helicopter. It had
a large screw-like wing made of starched
linen. In 1784, two Frenchmen named Launoy
and Bienvenu built the first model helicopter
in Europe that could fly.

18. Da Vinci’s sketch
Model of Helicopter from
Launoy and Bienvenu

19. HISTORY
By early 1900’s, small, powerful petrol
engines had been developed that made
manned helicopter flight possible. The first
ever was in 1907. The craft was a four-rotor
helicopter built by Louis Breguet, a French
Inventor. This helicopter lifted a human about
61 centimeters for a minute. Later in 1907, a
French mechanic name Paul Cornu made the
first free flight in a helicopter. He flew his
tandem-rotor aircraft 2 meters for about 20
seconds.

20. Paul Cornu in
his
first helicopter
Full length photograph

21. TYPES OF HELICOPTERS

22. SINGLE-ROTOR HELICOPTER
Has one main rotor mounted above its body. It
also has a second, smaller rotor mounted on
its tail. The main rotor may have 2 to 8 blades.
It provides the helicopter’s lifting-power. The
tail rotor has from 2 to 13 blades. It is mounted
vertically on the either side of the tail and so
spins at a right angle to the main rotor. The tail
rotor is used to control direction. It also
overcomes the tendency of the helicopter to
spin around.

23. TWIN-ROTOR HELICOPTER
Have 2 main rotors. The rotors turn in opposite
directions and so it doesn’t need for a tail rotor.
There are 2 types: The tandem-rotor helicopter
which has a main rotor mounted above each
end of the body and the coaxial-rotor helicopter
which has one rotor above the other.

24. SINGLE-ROTOR HELICOPTER

25. Tandem-rotor
Helicopter
Coaxial-rotor
Helicopter
TWIN-ROTOR HELICOPTERS

27. HELICOPTER PROPULSION

28. HELICOPTER PROPULSION
Helicopter rotor blades are rotary wings. When
an engine turns the rotors, the blades generate
lift as they whirl through the air.

29. HELICOPTER PROPULSION
Special type of wings help them create lift. A
wing’s upper surface is curved and the lower is
flat. As the wings move, air flows over and
under the wing. The air flows faster over the
wing than under the wing. There is less
pressure on the upper surface than the lower.
The air is pushing more strongly at the bottom
thus creates the lift.

31. BLADE ELEMENT THEORY
In rotary-wing aircraft e.g. helicopters, induced
drag decreases with increased aircraft
airspeed

33. HELICOPTER PROPULSION
Angle of attack
- the amount of lift by changing the angle
that the wings make with the airflow.

34. TAIL ROTOR
Newton's third law of motion requires that for
every action there is an equal and opposite
action. A typical single main rotor helicopter
has a rotor system mounted on a rotor mast.
The helicopter engine supplies power so that
the helicopter can turn the mast. When the
helicopter applies torque to the mast to spin
it, there is an equal-and-opposite torque
reaction which tries to turn the helicopter in
the opposite direction.