DGCA Module 8 Questions of Chapter 2 | Basic Aerodynamics

DGCA Module 8 Answer marked Questions | Basic Aerodynamics

1. The drag which is inversely proportional to square of velocity
a. Parasite drag
b. Induced drag
c. Infinite drag

2. Aileron provide which control
a. Longitudinal
b. Roll
c. Pitch

3. If an aircraft having infinite aspect ratio then it will not be subjected to
a. Wingtip vortices
b. Wingtip vortices and induced drag
c. Induced drag

4. The aileron control is used to provide control around
a. Lateral control in longitudinal plane
b. Longitudinal control in lateral plane
c. Both

5. In streamline, the air
a. The air is flow parallel to the main center line
b. Pressure drop is uniform
c. Velocity will be equal at each place

6. At high speed the induced drag
a. Less than 10% of total drag
b. Less than 25% of total drag
c. More than 25% of total drag

7. If the aspect ratio —————, the induced drag will be halved
a. Doubled
b. Halved
c. Not affected

8. The point at which laminar flow is changed to turbulent is
a. Transition point/bubble point
b. Turbulent flow
c. None of the above

9. The increase of angle of incidence from root to tip
a. Wash in
b. Wash out
c. Both

10. The angle between chord line and relative air flow is
a. Angle of incidence
b. Angle of attack
c. Longitudinal dihedral

11. The straight line which goes from the leading edge of the wing to the trailing edge is called
a. Camber line
b. Chord line
c. Angle of attack

12. The layer of air over the surface of an airfoil which is slower moving in
relation to the rest of the airflow is known as
a. Camber
b. Chord
c. Boundary layer

13. If aspect ratio is higher than induced drag is
a. More than 40%
b. More than 75%
c. Infinite

14. If induced drag is reduced
a. Span must be remains same
b. Span must be reduced
c. Aspect ratio must be higher

15. MTCS-higher Reynolds number
a. Supersonic – turbojet engine
b. Subsonic – aircrafts
c. None of the above

16. On a delta wing aircraft lift
a. Increases with increase in angle of attack
b. Decrease with increase in angle of attack
c. None of the above

17. Induced drag is a part of
a. Lift
b. Weight
c. Thrust

18. The drag is caused by the separation of the boundary layer
a. Form drag
b. Induced drag
c. Interference drag

19. NACA 0009 airfoil is having
a. More camber
b. Less camber
c. No camber

ALSO READ : DGCA Module 8 Questions from Chapter 1 | Physics of Atmosphere

20. Factors of drag primarily depends on
a. Speed of airflow over the wing and other parts
b. The interference between different parts of A/C and airflow
c. None of the above

21. Density is defined as
a. Weight / Volume
b. Volume / mass
c. Mass / Volume

22. With greater aspect ratio ———— will be reduced
a. Profile drag
b. Induced drag
c. Both a and b

23. Induced drag is not taken into consideration in
a. High speed
b. Medium speed
c. Low speed

24. With greater aspect ratio ———— will be reduced
a. Profile drag
b. Induced drag
c. Both a and b

25. When the AOA increases to the angle of maximum lift this is
known as
a. Stalling angle
b. Critical angle
c. Both

26. Rudder provides
a. Directional stability
b. Lateral stability
c. Longitudinal stability

27. An Ideal airfoil has
a. High maximum lift coefficient
b. Good lift/drag ratio
c. Both a and b

28. Efficiency of airfoil is
a. Lift over drag
b. Drag over lift
c. Weight over thrust

29. The point of intersection of the resultant force line of the airfoil is
called the
a. Chord line
b. Camber line
c. Center of pressure

30. When flap will extend
a. Stalling angle is increased
b. Stalling angle is decreased
c. Remains same

31. Aileron gives ——— control
a. Roll
b. Yaw
c. Pitch

32. If center of gravity of aircraft is forward of center of pressure than nose of
aircraft will
a. Drop
b. Rise
c. It depends on distance between CP and CG

33. The Newton’s law of mechanism that is applicable to air
a. 1st law & 2nd law
b. 1st law & 2nd law
c. 1st law & 2nd law & 3rd law

34. The point on a wing surface where boundary layer starts
a. Trailing edge
b. Leading edge
c. Transition point

35. An airfoil stalls at a
a. Certain Angle and certain speed
b. Certain Angle and not a certain speed
c. Not a certain Angle and certain speed

36. Mark the correct statement
a. Centre of pressure is the point on chord of wings from where drag force acts
b. Centre of pressure is the point on chord of wings from where lift force acts
c. Centre of pressure is the point on chord of wings from where weight force acts

37. Which of the following is profile drag
a. Skin friction drag
b. Induced drag
c. Wave drag

38. The movement of center of pressure is independent from
a. Lift
b. Drag
c. Weight

39. An ideal airfoil has
a. High max CL
b. Low minimum CD
c. Both (a) & (b)

40. Which control surface provide pith control
a. Elevator
b. Aileron
c. Flaps

41. Induced drag is affected due to
a. Lift
b. Drag
c. Climb

42. As long as you have lift, you have
a. Skin friction drag
b. Induced drag
c. Wave drag

43. Law applicable for equilibrium flight is
a. Newton 1st law
b. Newton 2nd law
c. Newton 3rd law

44. Elevator control
a. Pitch
b. Directional
c. Roll

45. As AOA increases
a. C of P moves forward
b. C of P moves rearwards
c. Remains constant

46. Lift of an aircraft produced more due to
a. increase in pressure on the upper surface
b. Increase in pressure on lower surface.
c. Decrease pressure on lower surface

47. Characteristics of airfoil depends on
a. Airflow
b. Curvature
c. Angle

48. High thickness of the airfoil at the leading edge, what happens to the stall
characteristics?
a. poor
b. Good
c. Excellent

49. Reynolds number
a. Is applicable to supersonic aircrafts
b. Is applicable to continuous flow
c. Both a and b

50. Movement of center of pressure is affected by
a. Centre of gravity
b. Angle of attack
c. Centre of drag

51. When slat is extended the max CL of the aerofoil may be increasing by as
much as
a. 20 %. b. 40 %. c. 60 %

52. Angle of airfoil is slightly negative will it generate lift
a. Do not generate lift
b. May be generate lift
c. None

53. At constant AOA, if density increases then L/D ratio
a. Increases
b. Decreases
c. Remains constant

54. Wave drag is generally produced at
a. Subsonic & Sonic Speed
b. Transonic & Supersonic Speed
c. Hypersonic Speed

55. On a swept wing aircraft if both wing tip loses lift simultaneously the aircraft will
a. Roll
b. Pitch nose up
c. Pitch nose down

56. The increase in kinetic energy due to increase in velocity is accompanied
by a corresponding decrease in
a. Static pressure
b. Dynamic Pressure
c. Stagnation Pressure

57. The geometric features of an airfoil section are
a. The camber of the center line
b. The position of maximum camber
c. The radius of curvature of the leading edge
d. All the above

58. Krueger flap is a
a. Leading edge flap
b. Trailing edge flap
c. Leading edge slat

59. Stagnation pressure
a. Static + dynamic
b. Static
c. Dynamic
60. The value of the dynamic pressure and hence the indicated speed at which this occurs will always be the _______ whatever the height.
a. Increases
b. Decreases
c. Same

61. Smooth surface encourages
a. Laminar flow
b. Boundary layer
c. Homogeneous layer

62. Airfoil with maximum camber well forward at leading edge will have___________ stall characteristics.
a. Poor
b. Good
c. Excellent

63. The streamline shapes which have given the least resistance at subsonic
speeds have had a
a. fineness ratio
b. pressure ratio
c. aspect ratio

64. A laminar boundary layer over the boundary layer over the whole surface of a wing the skin friction would be reduced to
about__________ of its value.
a. One – tenth
b. One – third
c. One – fourth
65. The turbulent layer has a much degree of shear at the surface and it is this which causes the skin fiction to be much
___________that it is for the laminar boundary layer.
a. Smaller
b. Higher
c. Same

66. Drag coefficient of a body is dependent on
a. The shape of the body
b. The square of the velocity
c. The density of the air
d. All the above
67. In subsonic speed the air is
a. Compressible
b. Incompressible
c. None

68. In supersonic speed the air is
a. Compressible
b. Incompressible
c. None

69. The angle between the chord of the aerofoil and some fixed datum line
in the aeroplane
a. Angle of attack
b. Riggers angle of incidence
c. Longitudinal dihedral angle

70. The upper surface by means of its decreased pressure which provides
the
a. Four – fifth of lift
b. Three – fifth of lift
c. Two – fifth of lift

71. The component has hardly any effect on the position of the center of pressure
a. Lift
b. Drag
c. Weight

72. In flat plate an increase of the angle of attack over the same angles
causes the center of pressure to move
a. Forward
b. Backward
c. Remains same

73. The pitching moment is positive when it tends to push the nose
a. Upwards
b. Downwards
c. Constant

74. Relation between CL& AOA
a. Directly proportional
b. Inversely proportional
c. None

75. L/D ratio increases very rapidly up to about
a. 0 deg
b. 3 deg or 4 deg
c. 15 deg

76.The L/D ratio increases very rapidly up to 3 or 4 degree at which angles the lift is nearly
a. 20 times the drag
b. 24 times the drag
c. 10 times the drag

77.At subsonic speeds the aerodynamic center is usually about
a. One – fourth of the chord from LE
b. Two – third of the chord from LE
c. One – Quarter of the chord from LE

78.NACA 4412 is
a. Symmetrical airfoil
b. Unsymmetrical airfoil
c. None

79.Aspect ratio for flight at subsonic speeds vary from
a. 6 to 1 up to about 10 to 1
b. 4 to 1 up to about 6 to 1
c. 2 to 1 up to about 5 to 1

80.While take off induced drag is
a. 20 % of total drag
b. 50 % of total drag
c. 70 % of total drag

81.When slat will extend
a. Stalling angle is decreased
b. Stalling angle is increased
c. Remains same

82. Lines which show the direction of the flow of the fluid at any particular
moment are called
a. Line of zero lift
b. Streamlines
c. Chord line

83. Speed of sound in gas
a. Directly proportional to temperature
b. Inversely proportional to temperature
c. No relation

84. The camber convex of airfoil in upper surface is
a. Smaller
b. Greater
c. Same

85. As velocity increases transition point on wing will moves
a. Towards leading edge
b. Towards trailing edge
c. No effect

86. The purpose of slat
a. To increase drag
b. To re-energize boundary layer
c. To decrease stalling angle

87. Fixed slat at high speed will give
a. Less drag
b. More drag
c. No change

88. Camber & split flap will give
a. Increases in Max CL
b. Increases in Drag
c. Both

89. Blown & jet flaps may be a serious disadvantage in the event of
a. Diving
b. Climbing
c. Power failure

90. Reynolds number is the ratio of
a. Inertia force to viscous force
b. Elastic to viscous force
c. Elastic to inertia force

91. If Reynolds number is increasing the flow will be
a. Laminar
b. Turbulent
c. Transition

92. If density is increasing the Reynolds number will be
a. Increasing
b. Decreasing
c. Remains same

93. If viscosity is increasing the Reynolds number will be
a. Increasing
b. Decreasing
c. Remains same

94. Airfoil with max camber well forward say at 15% to 20% of the chord may have
a. Low drag
b. High drag
c. No drag

95. There must be some point on the chord about which there is no change
in pitching moment is called
a. Line of zero lift
b. Aerodynamic center
c. Stagnation point

96. The concept of thrust is explained by
a. Newton’s 1st law
b. Newton’s2nd law
c. Newton’s 3rd law