This document discusses the basics of aerodynamics and the forces acting on aircraft in flight. It covers key concepts like: 1. Aerodynamic forces like lift, weight, thrust and drag that act on aircraft in motion through the air based on Newton's Laws of motion. 2. How the shape of airfoils and wings generate lift using Bernoulli's principle and how control surfaces like ailerons, elevators and rudders allow for rolling, pitching and yawing. 3. The different types of drag forces - induced, parasite and wave drag - and how configuration changes and altitude affect aircraft performance.

1. BASIC
AERODYNAMIC
Aerodynamic concerns the
motion of air and other
gaseous fluids and forces
acting on objects in motion
through the air.

2. BASIC
AERODYNAMIC
The science of the action
of air on an aircraft.

3. Newton’s Laws of Motion
Every objects persist in its
state of rest or uniform motion
in a straight line unless it is
compelled to change that state
by force impressed on it.

5. Newton’s Laws of Motion
A body will accelerate with
acceleration proportional to the
force and inversely proportional
to the mass.

6. constant mass
Force = mass x acceleration
Force = mass x change in velocity with time
The motion of an aircraft resulting from aerodynamic
forces and the aircraft weight and thrust can be
computed by using Newton’s 2nd
Laws of motion.
Differential form
Force = change of momentum with change of time

7. Newton’s Laws of Motion
For every action, there
is an equal and
opposite re-action.

9. Bernoulli's principle
Increase in the velocity
of flow will result in a
decrease in the static
pressure.

10. Bernoulli's principle

11. AIRFOIL

17. THE SHAPE OF THE MEAN
CAMBER

21. AIRFOIL TERMINOLOGY
• THE MEAN CAMBER LINE
• THE CHORD LINE
• THE CHORD
• THE MAXIMUM THICKNESS
• AERODYNAMIC FORCE
• CENTER OF GRAVITY
• THE AERODYNAMIC CENTER
• THE CENTER OF PRESSURE
• FLIGHT PATH
• RELATIVE WIND
• ANGLE OF ATTACK

22. THE MEAN CAMBER LINE
is a line drawn midway between the
upper and lower surfaces

23. THE CHORD LINE

24. THE CHORD
The length of the chord line and is
the characteristic dimension of
the airfoil section.

25. THICKNESS

26. AERODYNAMIC FORCE

28. AERODYNAMIC CENTER
Moment about the aerodynamic center is constant
with angle.
Aerodynamic center does not move with angle.

29. CENTER OF PRESSURE
Aerodynamic force acts through the center of pressure.
Center of pressure moves with angle of attack.

30. CENTER OF GRAVITY
The total weight of the airplane and its loads
is distributed throughout the aircraft and
concentrated at one given point

31. FLIGHT PATH

32. RELATIVE WIND
• Relative wind is the "wind" that acts exactly opposite
to the direction of flight.
• In the picture to the left the relative wind is horizontal
so this airplane is in level flight.

33. RELATIVE WIND
• Notice that when the airplane climbs the drag vector is still
parallel to the relative wind - as shown. In this case the
drag is no longer horizontal.

34. RELATIVE WIND
• The airplane is descending. Once again you can see
that the drag vector acts parallel to the relative wind.

35. ANGLE OF ATTACK
The angle between the chord line
relative to wind direction.

36. ANGLE OF ATTACK

38. DEVELOPMENT OF
AERODYNAMIC FORCES
THE USE OF THE POWER
AND FLIGHT CONTROLS
FOR CHANGING THE
FORCES OF LIFT,
WEIGHT, THRUST AND
DRAG.

39. AILERON

40. Rolling Motion

41. Rolling

42. Elevator – Horizontal Stabilizer

43. Pitching Motion

44. Pitching

45. Rudder - Vertical Stabilizer

46. Yawing Motion

47. Yawing

48. FORCES ACTING ON
AIRCRAFT IN FLIGHT
• LIFT
• WEIGHT
• THRUST
• DRAG
• CENTRIFUGAL FORCE

49. WHAT IS LIFT ?

50. WHAT IS WEIGHT ?

51. WHAT IS THRUST ?

52. WHAT IS DRAG ?

53. PRESSURE PATTERNS

54. PRESSURE PATTERNS

55. PRESSURE PATTERNS

56. PRESSURE PATTERNS

65. INDUCE DRAG

69. Upwash and downwash
fields around an airplane
create turbulence in flight

71. WINGLET
Winglets can be used to produce
extra lift, besides lower drag.
Mounted on the rear part of
the wing to minimize
interference effects.Drag
reduction rates are of the
order of 5 %.

76. Since there are two different
ways that lift is produced,
there are also two different
types of induced drag :
dynamic drag (Newtonian) and
pressure drag (Bernoulli).

77. DYNAMIC DRAG

78. PRESSURE DRAG

79. There are also skin-friction drag and form drag, which are referred to
as parasite drag.
All drag other than induced drag is parasite drag.
PARASITE DRAG

81. SPEED BRAKE

83. LIFT DUMPER

84. PROFILE DRAG

85. The dihedral angle is the angle made between one
wing and the horizontal, as viewed from the nose
or tail of the aircraft.
DIHEDRAL ANGLE
Dihedral is applied for purposes of stability.

87. UNHEDRAL ANGLE
Where the wings are set an angle such that
the tips are lower than the centre.
The opposite of DIHEDRAL.

88. C-17 Globemaster
Large transport aircraft with four jet engines.
Able to take off or land in short distances.

89. POLYHEDRAL ANGLE
A form of dihedral in which
there are one or more changes
of dihedral in each wing panel.

91. FIX WING
AERODYNAMICS

92. CONSTRUCTION

93. Cantilever Wing

94. Cantilever Wing

95. HIGH LIFT DEVICES

96. F L A P S

97. Slat and Slot

98. Flaps and Slat

102. Slotted Wing

103. DEFINITION
The amount of drag depends on :
1. Size of the aircraft.
2. Details of the shape and smoothness of
the aircraft.
3. Lifting efficiency of the wing.
4. Dynamic pressure ( density and speed ).

104. TYPES OF DRAG
There are three main types of drag
affecting performance of an aircraft:
• Induced drag.
• Skin friction of parasitic drag.
• Wave drag.

105. Induce Drag
• Induced drag is the most important form
of drag because it occurs as a result of
the force of lift which enables a plane to
remain airborne.
• The backward force on the plane is the
induced drag force.

106. Skin Drag
• Skin friction or parasitic drag is a simple
kind of drag that results from wind
resistance to the rough surfaces of an
aircraft. For example, when an F-16 is
loaded up with weapons and fuel tanks,
the plane’s aerodynamics are complicated.
• This creates drag which will affect flight
performance and G forces – that is,
forces of acceleration that pull a pilot
when he or she is in motion.

107. Wave Drag
• Wave drag is only found in jet fighters or
supersonic aircraft. When a plane moves
at supersonic speeds, it builds up a
tremendous front. A huge amount of
energy is required to move through these
waves and this resistance is called wave
drag.
• When the resulting shock wave hits the
ground, it is experienced by people of the
ground in the rattling form of a “sonic
boom.”

108. FORCES AFFECTING
PERFORMANCE

109. VARIATION FACTORS
• Change in weight
• Configuration
• Altitude

111. CONFIGURATION
vs
PERFORMANCES
• Accomplished by lowering the landing gear,
adding external stores, extending speed
brakes multiplied the area by the dynamic
pressure of the airstream is the parasite
drag.
• Increase drag requires more power to
maintain a certain velocity n affects the
range and endurance because higher fuel

116. ALTITUDE
vs
PERFORMANCES
• Increase in altitute – Decrease in air
density.
• Increase in velocity without increasing
the drag force.
• Higher true airspeed.

118. WINDS vs PERFORMANCES
Winds must be considered
because of their effect on
the ground speed.

119. Relative Velocity

120. Relative Velocity

129. SPEED REGIMES

136. SPEED OF SOUND

138. Shock Waves
The air pressure waves move away
from the airplane in all directions
at the speed of sound pile up ahead
of the airplane and compress and
then move out and back from the
plane, towards the ground.

141. Sound Barrier
• The sudden increase in air resistance,
aerodynamic drag that occurs when
an aircraft approaches the speed of
sound. This is also called the sonic
barrier.
• The speed of sound is 758 miles /
hour (1220 km / hour.