BASIC AERODYNAMICS

SEMESTER-I

FLYTECH AVIATION ACADEMY

SEMESTER EXAMINATION DECEMBER - 2014SEMESTER-I (FW)SUBJECT: BASIC AERODYNAMICS

TOTAL MARKS:100 SUBJECT CODE:

TIME: 2 1/2HRS

DATE

NAME: ROLL NO: PART-A (OBJECTIVE)1. On a swept wing aircraft if both wing tip sections lose lift simultaneously the

aircraft will

()a) roll

b) pitch nose up

c) pitch nose downd) sideslip

2. MTCS:

()a) Density altitude is pressure altitude corrected for temperature.

b) Pressure increases with pressure altitude.

c) The temperatutre remains constant upto 11,000 mtr.

d) Ennvironmental lapse rate refers to change in temperature of a mass of air as it moves upwards.3. On a straight wing aircraft, stall commences at the

()a) root on a high thickness ratio wingb) tip on a high thickness ratio wing

c) tip on a low thickness ratio wingd) root on a low thickness ratio wing4. On a high wing aircraft in a turn

()a) the up-going wing loses lift causing a de-stabilising effectb) the up-going wing loses lift causing a stabilising effect

c) the down-going wing gains lift causing a stabilising effect

d) the down-going wing loses lift causing a de-stabilising effect5. For the same angle of attack, the lift on a delta wing

()a) is greater than the lift on a high aspect ratio wingb) is lower than the lift on a high aspect ratio wingc) is the same as the lift on a high aspect ratio wing

d) none6. The ISA

()a) is taken from the equator

b) is taken from 45 degrees latitude

c) assumes a standard dayd) either (a) or (b)7. At higher altitudes as altitude increases, pressure

()a) decreases at constant rateb) increases at constant rate

c) increases exponentially

d) decreases exponentially

8. The thrust-drag couple overcomes the lift-weight couple. What direction of

force is required to be produced by the tail of the aircraft to maintain straight

and level flight

()a) upwards

b) downwards

c) sideways

d) none

9. When the pressure is half of that at sea level, what is the altitude?

()a) 12,000 ft

b) 8,000 ftc) 18,000 mtr.d) 18,000 ft

10. During a turn, the stalling angle

()a) increases

b) decreases

c) remains the samed) decreases and then remain the same

11. If gauge pressure on a standard day at sea level is 25 PSI, the absolute

pressure is

()a) 10.3 PSI

b) 43.8 PSIc) 11.7 PSId) 39.69 PSI12. The C of G moves in flight. The most likely cause of this is

()a) movement of passengers

b) movement of the centre of pressure

c) consumption of fuel and oilsd) improper loading of aitcraft

13. In the diagram mentioned above what does the air circulation in zone A stand for : ()a) Downwash b) Up wash

c) Both downwash and bound vortex14. In the diagram mentioned above what does point D stand for:

()a) Centre of pressure

b) Centre of gravity

c) Centre of symmetry

d) None15. If value of i in the diagram above decreases then lift :

()a) Increases

b) Decreases

c) Remains unaffectedd) Decreases and may produce negative lift on further decrement16. Magnus effect states that zone B in above diagram experiences ________ and increases with an increase in ________:

()a) Low pressure and AOA

b) High pressure and AOA

c) High pressure and camber

d) Low pressure and camber

17. Pressure decreases

()a) proportionally with a decrease in temperature

b) inversely proportional to temperature

c) Pressure and temperature are not related

18. What is sea level pressure?

()a) 1013.2 mb

b) 1012.3 mbc) 1032.2 mb

d) 1013.2 pa19. When the weight of an aircraft increases, the minimum drag speed

()a) decreasesb) increases

c) remains the same

20. A graph showing the angle of an attack of an aircraft /glider versus its lift-coefficient represents :

a) Stall curve

()b) Polar curve

c) Aerodynamic efficiency

d) None

21. When an aircraft experiences induced drag

()a) air flows under the wing span-wise towards the root and on top of the wing

span-wise towards the tipb) air flows under the wing span-wise towards the tip and on top of the wing spanwise

towards the rootc) Neither a) or b) since induced drag does not caused by span-wise flow

22. At stall, the wingtip stagnation point

()a) doesnt moveb) moves toward the upper surface of the wing

c) moves toward the lower surface of the wing d) none23. How does IAS at the point of stall vary with height?

()a) It is practically constant

b) It increases

c) It decreases

d) It increases than decreases24. The rigging angle of incidence of an elevator is

()a) the angle between the mean chord line and the horizontal in the rigging

position

b) the angle between the bottom surface of the elevator and the horizontal in the

rigging position

c) the angle between the bottom surface of the elevator and the longitudinal datum

25. What is the lapse rate with regard to temperature?

()a) 1.98C per 1000 ft

b) 3F per 1000 ft for moist airc) 5F per 1000 ft for dry air d) All the above26. What happens to load factor as you decrease turn radius?

()a) It increases

b) It decreases

c) It remains constant

27. If you steepen the angle of a banked turn without increasing airspeed or angle

of attack, what will the aircraft do?

()a) It will remain at the same height

b) It will skid with attendant loss of heightc) It will stalld) It will sideslip with attendant loss of height28. Which type of flap changes the area of the wing?

()a) Fowler

b) Split

c) Slotted

d) Both a & c.29. Dihedral wings combat instability in

()a) pitch

b) yawc) sideslip

30. To stop aircraft decreasing in height during a sideslip, the pilot can

()a) advance the throttle

b) pull back on the control column c) adjust the rudder positiond) move the control column in a direction opposite to that of side slip. 31. What control surface movements will make an aircraft fitted with ruddervators

yaw to the left?

()a) Left ruddervator lowered, right ruddervator raised

b) Right ruddervator lowered, left ruddervator raised

c) Both ruddervators raisedd) Both ruddervators lowered

32. When a leading edge slat opens, there is a gap between the slat and the wing.

This is

()a) to allow it to retract back into the wing

b) to allow air through to re-energize the boundary layer on top of the wing

c) to keep the area of the wing the same

d) to prevent the spanwise flow of air 33. Which of the following is true?

()a) Lift acts at right angles to the wing chord line and weight acts vertically down

b) Lift acts at right angles to the relative airflow and weight acts vertically

down

c) Lift acts at right angles to the relative airflow and weight acts at right

angles to the aircraft centre line

d) none34. If the wing tips stall before the root on a swept wing aircraft, the aircraft

Will

()a) roll

b) pitch nose up

c) pitch nose down

35. Increase in angle of incidence from wing root to wing tip is known as :

()a) Sweep back

b) Dihedral

c) Wash in

d) Wash out36. If MAC is 200 and C.G falls 30 behind the leading edge of the MAC then it lies at__% of the MAC:

a) 20%

()b) 15%

c) 30%

d) None37. Deployment of a split flap will

()a) increase wing area and increase drag

b) pitch the nose down and decrease drag

c) increase camber and increase drag

38. The ratio of the length of the span to the depth of the wing is known as:

()a) Fineness ratio

b) Aspect ratio

c) Thickness ratio

d) None

39. Aircraft flying in the transonic range most often utilize

()a) sweptback wings

b) advanced supercritical airfoils

c) high wings40. The airflow into the inlet of a gas turbine engine must be _______ for maximum effectiveness .

a) Supersonic

()b) subsonic

c) transonic

d) hypersonic41. What happens to air flowing at the speed of sound when it enters a converging

()duct?

a) Velocity decreases, pressure and density increase

b) Velocity increases, pressure and density decreases

c) Velocity, pressure and density increase

d) Velocity, pressure and density decreases42. If the speed of an aircraft is between 1.25 & 2.5 mach then it is said to be :

()

a) Subsonic flight

b) Transonic flight

c) Hypersonic flight

d) Supersonic flight

43. An aircraft, which is longitudinally stable, will tend to return to level

()flight after a movement about which axis?a) Pitch b) Roll c) Yaw44. Vortex generators on the wing are most effective at

()a) high speed

b) low speed

c) high angles of attackd) high altitude

45. If the free stream mach no. for a particular aerofoil is 0.78 for which the local mach no. is 1 then the critical mach no. for that partcular aerofoil is :

()

a) 0.085

b) 0.85c) 8.5

d) 0.7846. At the point of shock wave formation :

()

a) The pressure & temperature simultaneously increases.

b) As in a & the velocity is reduced .

c) As in b & the incipient shock wave formed is at right angle to the surface .

d) As in b & the incipient shock wave formed is at right angle to thedirection of airflow.

47. Schlieren photography is used for :

()

a) Visualisation of density changes

b) As in a & Visualisation of shock wave formation

c) Visualisation of temperature change & therefore the shock wave formation

d) None

48. The most efficient boundary layer control method is accomplished by using :

()a) wing fences

b) vortex generators

c) wing slots49. Stall strips are always

()a) made of metal

b) on the leading edge of a wing c) fitted forward of the aileronsd) as in (b) and cause the wing root to stall first50. Area rule states that If drag is to be kept minimum then :

()

a) The cross-sectional area of the aerofoil should increase gradually to a maximum & then decrease .

b) As in a & holds good for transonic speeds .

c) As in a & holds good for high subsonic speeds only.

d) Only b is correct.51. The airflow into the inlet of a gas turbine engine must be _______ for maximum effectiveness .

a) Supersonic

()

b) subsonic

c) transonic

d) hypersonic52. The tail rotor employed in helicopter is to provide :

()

a) Anti torque effect

b) Generation of lift

c) Both a & bd) None53. The state of flight when the main rotor system is being turned by the force of relative wind rather than engine power :

()

a) Hovering

b) Feathering

c) Auto rotation

d) None

54. In context of mach angle cone which of the following is correct ?

()

a) The greater the mach no. the more obtuse is the mach angle.

b) The lesser the mach no. the less acute is the mach angle.

c) The lesser the mach no. the more acute is the mach angle.

d) None

55. The relationship between induced drag and airspeed is, induced drag is

()a) directly proportional to the square of the speed

b) inversely proportional to the square of the speed

c) directly proportional to speed

56. Low lift to drag ratio is the charecteristic feature of :

()

a) Supersonic aerofoil

b) Hypersonic aerofoil

c) Subsonic aerofoil

d) Ultrasonic aerofoil57. The method of control by which the pitch of rotor blade is varried individually to control the tilt of the rotor disc :

()a) Cyclic Pitch Control

b) Collective Pitch Control

c) Disc Loading

d) None58. The part responsible for automatically disconnecting the main rotor from the engine when the engine stops or slows belows the equivalent of rotor r.p.m :

()

a) Articulated Rotor

b) Delta hinge

c) Freewheeling unit

d) None

59. Ground effect is typically effective at :

()

a) Less than two rotor dia above the surface

b) Less than two & a half rotor dia above the surface

c) Less than one rotor dia above the surface

d) Less than one & a half rotor dia above the surface

60. The difference in lift between advancing & retreating blades is known as :

()

a) dissymetry of lift

b) translational lift

c) coning

d) noneFLYTECH AVIATION ACADEMY

SEMESTER EXAMINATION DECEMBER - 2014SEMESTER-I (FW)SUBJECT: BASIC AERODYNAMICS

TOTAL MARKS:100 SUBJECT CODE:

TIME: 2 1/2HRS

DATE

NAME: ROLL NO: PART-B (OBJECTIVE)01. The angle of attack which gives the best L/D ratio

()a) decreases with a decrease in density

b) in unaffected by density changes

c) increases with a decrease in densityd) none of the above02. When a leading edge slat opens, there is a gap between the slat and the wing. This is :

()a) to allow it to retract back into the wing

b) to allow air through to re-energize the boundary layer on top of the wing

c) to keep the area of the wing the same

d) to prevent the spanwise flow of air03. Low wing loading

()a) increases stalling speed, landing speed and landing run

b) increases lift, stalling speed and manoeuvrability

c) decreases stalling speed, landing speed and landing rund) decreases stalling speed & increases lift.04. Due to the change in downwash on an un-tapered wing (i.e. one of constant

chord length) it will

()a) not provide any damping effect when rolling

b) tend to stall first at the root

c) not suffer adverse yaw effects when turningd) dont bring any change05. True stalling speed of an aircraft increases with altitude

()a) because reduced temperature causes compressibility effect

b) because air density is reduced

c) because humidity is increased and this increases drag

d) the statement stands incorrect06. As a general rule, if the aerodynamic angle of incidence (angle of attack) of

an aerofoil is slightly increased, the centre of pressure will

()a) never move

b) move forward towards the leading edge

c) move towards the tip

d) moves rearward towards the trailing edge07. The "wing setting angle" is commonly known as

()a) angle of incidence

b) angle of attack

c) angle of dihedral

d) none of the above08. On a very humid day, an aircraft taking off would require

()a) a shorter take off run

b) a longer take off run

c) humidity does not affect the take off run

d) none of the above09. An aircraft is flying at 350 MPH, into a head wind of 75 MPH, what will its

ground speed be?

()a) 175 mph

b) 275 mph

c) 200 mph

d) 425mph10. When does the angle of incidence change?

()a) When the aircraft attitude changes

b) When the aircraft is ascending or descending

c) It never changes

d) when the aircraft is taking a turn11. As the angle of attack decreases, what happens to the centre of pressure?

()a) It moves forward

b) It moves rearwards

c) Centre of pressure is not affected by angle of attack decrease

d) first moves forward than rearward 12. A decrease in pressure over the upper surface of a wing or aerofoil is

responsible for

()a) approximately (one half) of the lift obtainedb) approximately 1/3 (one third) of the lift obtained

c) approximately (one half) of the lift obtained

d) approximately 2/3 (two thirds) of the lift obtained 13. Which of the four forces act on an aircraft?

()a) Lift, gravity, thrust and drag

b) Weight, gravity, thrust and drag

c) Lift, weight, gravity and dragd) lift, upthrust, weight & drag

14. Which of the following types of drag increases as the aircraft gains altitude?

()a) Parasite drag

b) Induced drag

c) Interference drag

d) form drag15. Correcting for a disturbance, which has caused a rolling motion about the

()longitudinal axis, would re-establish which of the following?

a) Lateral stability

b) Directional stability

c) Longitudinal stability

d) lateral instability16. The layer of air over the surface of an aerofoil which is slower moving, in

relation to the rest of the airflow, is known as

()a) camber layer

b) transition layerc) none of the above

d) boundary layer 17. What is a controlling factor of turbulence and skin friction?

()a) Aspect ratio

b) Fineness ratio

c) Counter-sunk rivets used on skin exterior

d) none of the above18. Changes in aircraft weight

()a) will not affect total drag since it is dependant only upon speed

b) cause corresponding changes in total drag due to the associated lift change

c) will only affect total drag if the lift is kept constant

d) will only affect the total lift19. In a bank and turn

()a) extra lift is not required

b) extra lift is not required if thrust is increased

c) extra lift is required

d) none of the above20. To maintain straight and level flight on the aeroplane shown, with a decrease

in tail-plane download the mainplane lift would have to

()a) remain constant

b) decrease than increasec) increase

d) decrease 21. To achieve the maximum distance in a glide, the recommended air speed is

()a) as close to the stall as practical

b) as high as possible with VNE

c) the speed where the L/D ratio is maximum

d) as low as possible22. If the C of G is aft of the Centre of Pressure

()a) the aircraft pitches down with increasing speedb) when the aircraft sideslips, the C of G causes the nose to turn into the

sideslip thus applying a restoring moment

c) when the aircraft yaws the aerodynamic forces acting forward of the Centre of

Pressured) changes in lift produce a pitching moment which acts to increase the change in

lift23. Directional stability is maintained

()a) by the mainplanes, and controlled by the ailerons

b) by the tailplane, and controlled by the elevators

c) by the keel surface and fin, and controlled by the rudder

d) by the main planes only 24. Due to the interference effects of the fuselage, when a high wing aeroplane

Sideslips

()a) the accompanying rolling due to keel surface area is destabilizing

b) the accompanying lift changes on the wings produces a stabilizing effect

c) the accompanying rolling due to the fin is destabilizing

d) none of the above25. The power required in a horizontal turn

()a) is greater than that for level flight at the same airspeed

b) must be the same as that for level flight at the same airspeed

c) is less than that for level flight at the same airspeed

d) none 26. A wing mounted stall sensing device is located

()a) always mounted at the rootb) always at the wing tip

c) always on the top surface

d) usually on the under surface 27. For an aircraft in a glide

()a) thrust, drag, lift and weight act on the aircraft

b) weight, lift and drag act on the aircraft

c) weight and drag only act on the aircraft

d) thrust and drag only act on the aircraft28. The upper part of the wing in comparison to the lower

()a) develops more lift

b) develops the same lift

c) develops less lift

d) none29. What effect would a forward CG have on an aircraft on landing?

()a) Increase stalling speed

b) No effect on landing

c) Reduce stalling speed

d) induce greater landing roll30. QNH refers to

()a) quite near horizon

b) setting the altimeter to zero

c) setting the mean sea level atmospheric pressure in accordance with ICAO

standard atmosphere i.e. 1013 millibarsd) setting the mean sea level atmospheric pressure so an altimeter reads the

aerodrome altitude above mean sea level

31. QNE refers to

()a) Setting an altimeter to read aerodrome altitude above sea level

b) quite new equipment

c) setting the mean sea level atmospheric pressure in accordance with ICAO

standard atmosphere i.e. 1013.2 millibars

d) setting the mean sea level atmospheric pressure so an altimeter reads the

aerodrome altitude above mean sea level

32. An aspect ratio of 8 would mean

()a) span 64, mean chord 8

b) mean chord 64 , span 8

c) span squared 64 ,chord 8d) none33. If an aircraft in level flight loses engine power it will

()a) pitch nose up

b) pitch nose down

c) not change pitch without drag increasing

d) none34. QFE is

()a) sea level pressure

b)quadrantal field elevtion & indicates airfield pressure

c) difference between sea level and airfield pressure

d) quadrantal field elevation35. The lift /drag ratio at stall

()a) increases

b) decreases

c) is unchanged

d) none36. During a climb from a dive

()a) the thrust required is greater than required for level flight

b) thrust is invariantly independent of decent speedc) the thrust required is the same as for level flight

d) the thrust required is lower than for level flight 37. Angle of attack on a down going wing in a roll

()a) increases

b) decreases

c) unaffected

d) increases & become negative38. Stall inducers may be fitted to a wing

()a) at the tip to cause the root to stall first

b) at the root to cause the tip to stall first

c) at the root to cause the root to stall first

d) at the tip to cause the tip to stall first39. With increasing altitude pressure decreases and

()a) temperature decreases at the same rate as pressure reduces

b) temperature decreases but at a lower rate than pressure reduces

c) temperature remains constant to 8000ft

d) temperature increases40. When deployed a Krueger Flap

()a) increases the leading edge camber

b) allows high pressure air from beneath the wing to flow to the top

c) energizes the air flowing over the ailerons

d)decreases speed thereby reducing lift 41. Which conditions will give the shortest take off distance?

()a) Hot Humid day at high elevation

b) Cold winter day at sea level

c) Hot summer day at sea level

d) none42. The optimum angle of attack of an aerofoil is the angle at which

()a) the aerofoil produces maximum lift

b) the aerofoil produces zero lift

c) the highest lift/drag ratio is produced

d) the least lift/drag ratio is obtained43. The transition point on a wing is the point where

()a) the flow separates from the wing surface

b) the boundary layer flow changes from laminar to turbulent

c) the flow divides to pass above and below the wing

d) the flow passing above and below the wing rejoins44. The boundary layer of a body in a moving air stream is

()a) a thin layer of air over the surface where the air is stationary

b) a layer of separated flow where the air is turbulent

c) a layer of air over the surface where the airspeed is changing from free stream

speed to zero speedd) none45. If the free stream mach no. for a particular aerofoil is 0.78 for which the local mach no. is 1 then the critical mach no. for that partcular aerofoil is :

()a) 0.78

b) 0.85

c) 8.5

d) 0.085

46. At the point of shock wave formation :

()

a) The pressure & temperature simultaneously increases.

b) As in a & the velocity is reduced .

c) As in b & the incipient shock wave formed is at right angle to the surface .

d) As in b & the incipient shock wave formed is at right angle to thedirection of airflow.

47. Schlieren photography is used for :

()

a) Visualisation of density changes

b) As in a & Visualisation of shock wave formation

c) Visualisation of temperature change & therefore the shock wave formation

d) None

48. The most efficient boundary layer control method is accomplished by

using :

()a) wing fences

b) vortex generators

c) wing slots

49. Stall strips are always

()a) made of metal

b) on the leading edge of a wing and cause the wing root to stall

c) fitted forward of the ailerons

50. Area rule states that If drag is to be kept minimum then :

()

a) The cross-sectional area of the aerofoil should increase gradually to a maximum & then decrease .

b) As in a & holds good for transonic speeds .

c) As in a & holds good for high subsonic speeds only.

d) Only b is correct.51. The airflow into the inlet of a gas turbine engine must be _______ for maximum effectiveness .

a) Supersonic

()

b) subsonic

c) transonic

d) hypersonic52. The tail rotor employed in helicopter is to provide :

()

a) Anti torque effect

b) Generation of lift

c) Both a & bd) None

53. The state of flight when the main rotor system is being turned by the force of relative wind rather than engine power :

()

a) Hovering

b) Feathering

c) Auto rotation

d) None

54. In context of mach angle cone which of the following is correct ?

()

a) The greater the mach no. the more obtuse is the mach angle.

b) The lesser the mach no. the less acute is the mach angle.

c) The lesser the mach no. the more acute is the mach angle.

d) None

55. The relationship between induced drag and airspeed is, induced drag is

()a) directly proportional to the square of the speed

b) inversely proportional to the square of the speed

c) directly proportional to speed

56. Low lift to drag ratio is the charecteristic feature of :

()

a) Supersonic aerofoil

b) Hypersonic aerofoil

c) Subsonic aerofoil

d) Ultrasonic aerofoil57. The method of control by which the pitch of rotor blade is varried individually to control the tilt of the rotor disc :

()a) Cyclic Pitch Control

b) Collective Pitch Control

c) Disc Loading

d) None58. The part responsible for automatically disconnecting the main rotor from the engine when the engine stops or slows belows the equivalent of rotor r.p.m :

()

a) Articulated Rotor

b) Delta hinge

c) Freewheeling unit

d) None

59. Ground effect is typically effective at :

()

a) Less than two rotor dia above the surface

b) Less than two & a half rotor dia above the surface

c) Less than one rotor dia above the surface

d) Less than one & a half rotor dia above the surface

60. The difference in lift between advancing & retreating blades is known as :

()

a) dissymetry of lift

b) translational lift

c) coning

d) noneSUBJECTIVE QUESTIONS :SET-A (ANSWER ANY EIGHT) :1. Explain the motions of aircraft about different axis with diagram.

2. Differentiate between laminar and turbulent flow.

3. What are the types of landing gear arrangement ? Explain the advantages of any one of them.

4. Briefly define the following:

a. Angle of attack

b. Dihedral angle

c. Adiabatic lapse rated. Wash ine. Critical mach no.

5. Explain how roll causes yaw and yaw causes roll?

6. Define critical angle of attack and polar curve. Draw the stall curve for an asymmetric aerofoil.7. Define the forces acting on an aircraft in flight.

8. How do dihedral effect helps in roll stability and sweep back in directional stability?

9. Give the mathematical equation for drag coefficient and explain the terms.

10. What are the different kinds of dynamic stability and what are the factors affecting lateral stability?SUBJECTIVE QUESTIONS :SET-B (ANSWER ANY EIGHT)1. Explain the following:

a. Environmental lapse rate

b. Pressure altitude

c. Angle of incidence

d. Stagnation point

e. Wash out

2. Explain magnus effect along with diagram and Bernoullis theory.

3. How induced drag is created and how can it be reduced ?4. What and how are the forces acting on aircraft while it is taking a turn? Explain with diagram.

5. Explain the three kinds of stability about different axes and the factors affecting it.

6. Define the two types of ailerons and why are they required? Define spoilerons, elevons and ruddervators.7. What is boundary layer control ? explain the different methods of achieving it. 8. How is sonic boom caused and what are the factors affecting it?9. Give the mathematical equation for lift coefficient and explain the terms.

10. How many types of tabs are there ? Brief them out.

SET A MCQs KEYS FOR BASIC AERODYNAMICS SEM EXAM :

1B31A

2A32B

3A33B

4C34B

5B35C

6B36D

7D37C

8A38A

9D39A

10C40B

11D41A

12C42C

13B43A

14A44C

15D45D

16D46D

17A47B

18A48C

19A49D

20A50B

21B51B

22C52A

23A53C

24A54B

25D55A

26A56A

27D57A

28D58C

29C59C

30A60A

SET B MCQs KEYS FOR BASIC AERODYNAMICS SEM EXAM :

1B31C

2B32A

3D33B

4B34B

5B35B

6B36D

7A37A

8B38C

9B39B

10C40A

11B41B

12D42A

13A43B

14B44C

15A45A

16D46D

17C47B

18B48C

19C49B

20D50B

21C51B

22D52A

23C53C

24B54B

25A55A

26D56A

27B57A

28A58C

29A59C

30D60A