Module 08 Basic Aerodynamics 100 Important Sentences for Revision

1. Principles of Flight

1. Aerodynamics is the study of air in motion around bodies.
2. Airflow can be laminar or turbulent.
3. Lift, weight, thrust, and drag are the four main forces of flight.
4. Lift acts upward, opposing weight.
5. Thrust moves the aircraft forward, opposing drag.
6. Weight always acts toward the center of the Earth.
7. Drag resists the motion of the aircraft through air.
8. Flight occurs when lift equals weight and thrust equals drag.
9. Bernoulli’s principle explains pressure differences creating lift.
10. Newton’s Third Law also contributes to lift production.

2. Air Properties

11. Air is a mixture of gases, mainly nitrogen and oxygen.
12. Air pressure decreases with altitude.
13. Air density decreases as temperature or altitude increases.
14. Standard atmosphere is defined at sea level as 15°C and 1013.25 hPa.
15. Density altitude affects aircraft performance.
16. Humid air is less dense than dry air.
17. Cold air increases lift and engine performance.
18. Warm air decreases lift and thrust.
19. Air viscosity increases slightly with temperature.
20. Pressure, temperature, and density are interrelated.

3. Pressure and Airflow

21. Static pressure is the pressure of still air.
22. Dynamic pressure is due to motion of air.
23. Total pressure = static pressure + dynamic pressure.
24. The Pitot tube measures total pressure.
25. The static port measures static pressure.
26. The airspeed indicator uses both static and total pressure.
27. Airflow speed affects lift production directly.
28. Smooth airflow over a wing is essential for lift.
29. Turbulent airflow increases drag.
30. Streamlines show the direction of air movement.

4. Lift and Drag

31. Lift acts perpendicular to relative airflow.
32. Drag acts parallel and opposite to relative airflow.
33. Lift increases with airspeed and angle of attack.
34. The coefficient of lift depends on wing shape and angle.
35. Induced drag is caused by lift generation.
36. Parasite drag includes form, skin friction, and interference drag.
37. Total drag is the sum of induced and parasite drag.
38. Minimum drag occurs at best lift-to-drag ratio.
39. High-lift devices increase lift during takeoff and landing.
40. Flaps increase both lift and drag.

5. Wing Design and Airfoils

41. Airfoil is the cross-section of a wing or blade.
42. The chord line joins the leading and trailing edges.
43. The camber is the curvature of the airfoil.
44. The angle between chord line and relative airflow is the angle of attack.
45. The point where airflow separates is called the separation point.
46. Center of pressure is the point where total lift acts.
47. A symmetrical airfoil has equal upper and lower surfaces.
48. A cambered airfoil produces lift even at zero angle of attack.
49. A high aspect ratio wing has long span and small chord.
50. Low aspect ratio wings provide better maneuverability.

6. Stalling and Stability

51. A stall occurs when the angle of attack exceeds the critical angle.
52. Critical angle is typically around 15 to 18 degrees.
53. Stall reduces lift dramatically and increases drag.
54. Recovery from stall requires reducing the angle of attack.
55. The center of gravity affects stability and stall behavior.
56. Static stability is the initial tendency to return to equilibrium.
57. Dynamic stability describes the aircraft’s long-term motion.
58. Longitudinal stability is about the pitch axis.
59. Lateral stability is about the roll axis.
60. Directional stability is about the yaw axis.

7. Control Surfaces

61. Ailerons control roll about the longitudinal axis.
62. Elevators control pitch about the lateral axis.
63. Rudder controls yaw about the vertical axis.
64. Trim tabs reduce pilot control forces.
65. Balance tabs assist in control movement.
66. Servo tabs move opposite to the control surface to aid movement.
67. Flaps increase lift and drag during low-speed flight.
68. Slats delay stall by increasing critical angle of attack.
69. Spoilers reduce lift and increase drag.
70. Air brakes increase drag for descent and landing.

8. Flight Maneuvers

71. Climb occurs when thrust exceeds drag.
72. Descent occurs when weight exceeds lift.
73. Level flight requires lift equal to weight.
74. A turn is produced by banking the aircraft.
75. The horizontal component of lift causes a turn.
76. The vertical component of lift opposes weight.
77. Load factor increases during turns.
78. Load factor is the ratio of total lift to weight.
79. Steeper turns increase stall speed.
80. Excessive load factor can cause structural damage.

9. Compressibility and Mach Number

81. At high speeds, air compressibility affects flight characteristics.
82. Mach number = aircraft speed / speed of sound.
83. Speed of sound decreases with altitude.
84. Subsonic flight is below Mach 1.
85. Transonic flight is between Mach 0.8 and 1.2.
86. Supersonic flight is above Mach 1.2.
87. Shock waves form during transonic flight.
88. Shock waves cause drag rise and control issues.
89. Mach tuck is a nose-down tendency at high Mach numbers.
90. Swept wings delay the onset of shock waves.

10. Aircraft Performance

91. Takeoff performance depends on weight, wind, and density altitude.
92. Climb performance decreases with high temperature or altitude.
93. Lift-to-drag ratio affects range and endurance.
94. Glide ratio is the distance traveled horizontally per unit height lost.
95. The best glide speed gives maximum range.
96. Ground effect reduces induced drag near the surface.
97. Wingtip vortices create induced drag.
98. Fuel efficiency improves at higher altitudes.
99. Center of gravity within limits ensures safe flight performance.
100. Understanding aerodynamics improves safety and efficiency in flight.

  

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