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# Aerodynamics slide

AVIATION KNOWLEDGE

AVIATION KNOWLEDGE

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### Aerodynamics slide

1. 1. BASIC AERODYNAMIC Aerodynamic concerns the motion of air and other gaseous fluids and forces acting on objects in motion through the air.
2. 2. BASIC AERODYNAMIC The science of the action of air on an aircraft.
3. 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.
4. 4. Newton’s Laws of Motion A body will accelerate with acceleration proportional to the force and inversely proportional to the mass.
5. 5. 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
6. 6. Newton’s Laws of Motion For every action, there is an equal and opposite re-action.
7. 7. Bernoulli's principle Increase in the velocity of flow will result in a decrease in the static pressure.
8. 8. Bernoulli's principle
9. 9. AIRFOIL
10. 10. THE SHAPE OF THE MEAN CAMBER
11. 11. 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
12. 12. THE MEAN CAMBER LINE is a line drawn midway between the upper and lower surfaces
13. 13. THE CHORD LINE
14. 14. THE CHORD The length of the chord line and is the characteristic dimension of the airfoil section.
15. 15. THICKNESS
16. 16. AERODYNAMIC FORCE
17. 17. AERODYNAMIC CENTER Moment about the aerodynamic center is constant with angle. Aerodynamic center does not move with angle.
18. 18. CENTER OF PRESSURE Aerodynamic force acts through the center of pressure. Center of pressure moves with angle of attack.
19. 19. CENTER OF GRAVITY The total weight of the airplane and its loads is distributed throughout the aircraft and concentrated at one given point
20. 20. FLIGHT PATH
21. 21. 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.
22. 22. 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.
23. 23. RELATIVE WIND • The airplane is descending. Once again you can see that the drag vector acts parallel to the relative wind.
24. 24. ANGLE OF ATTACK The angle between the chord line relative to wind direction.
25. 25. ANGLE OF ATTACK
26. 26. DEVELOPMENT OF AERODYNAMIC FORCES THE USE OF THE POWER AND FLIGHT CONTROLS FOR CHANGING THE FORCES OF LIFT, WEIGHT, THRUST AND DRAG.
27. 27. AILERON
28. 28. Rolling Motion
29. 29. Rolling
30. 30. Elevator – Horizontal Stabilizer
31. 31. Pitching Motion
32. 32. Pitching
33. 33. Rudder - Vertical Stabilizer
34. 34. Yawing Motion
35. 35. Yawing
36. 36. FORCES ACTING ON AIRCRAFT IN FLIGHT • LIFT • WEIGHT • THRUST • DRAG • CENTRIFUGAL FORCE
37. 37. WHAT IS LIFT ?
38. 38. WHAT IS WEIGHT ?
39. 39. WHAT IS THRUST ?
40. 40. WHAT IS DRAG ?
41. 41. PRESSURE PATTERNS
42. 42. PRESSURE PATTERNS
43. 43. PRESSURE PATTERNS
44. 44. PRESSURE PATTERNS
45. 45. INDUCE DRAG
46. 46. Upwash and downwash fields around an airplane create turbulence in flight
47. 47. 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 %.
48. 48. 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).
49. 49. DYNAMIC DRAG
50. 50. PRESSURE DRAG
51. 51. 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
52. 52. SPEED BRAKE
53. 53. LIFT DUMPER
54. 54. PROFILE DRAG
55. 55. 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.
56. 56. UNHEDRAL ANGLE Where the wings are set an angle such that the tips are lower than the centre. The opposite of DIHEDRAL.
57. 57. C-17 Globemaster Large transport aircraft with four jet engines. Able to take off or land in short distances.
58. 58. POLYHEDRAL ANGLE A form of dihedral in which there are one or more changes of dihedral in each wing panel.
59. 59. FIX WING AERODYNAMICS
60. 60. CONSTRUCTION
61. 61. Cantilever Wing
62. 62. Cantilever Wing
63. 63. HIGH LIFT DEVICES
64. 64. F L A P S
65. 65. Slat and Slot
66. 66. Flaps and Slat
67. 67. Slotted Wing
68. 68. 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 ).
69. 69. TYPES OF DRAG There are three main types of drag affecting performance of an aircraft: • Induced drag. • Skin friction of parasitic drag. • Wave drag.
70. 70. 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.
71. 71. 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.
72. 72. 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.”
73. 73. FORCES AFFECTING PERFORMANCE
74. 74. VARIATION FACTORS • Change in weight • Configuration • Altitude
75. 75. 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
76. 76. ALTITUDE vs PERFORMANCES • Increase in altitute – Decrease in air density. • Increase in velocity without increasing the drag force. • Higher true airspeed.
77. 77. WINDS vs PERFORMANCES Winds must be considered because of their effect on the ground speed.
78. 78. Relative Velocity
79. 79. Relative Velocity
80. 80. SPEED REGIMES
81. 81. SPEED OF SOUND
82. 82. 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.
83. 83. 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.