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Unit 1: Steady Unaccelerated Flight - Practice Quiz

ASE305 — Flight Mechanics 60 Questions
0 Correct 0 Wrong 60 Left
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1 What is meant by steady, unaccelerated flight?

Introduction Easy
A. Flight with constant velocity
B. Flight with changing direction
C. Flight with decreasing speed
D. Flight with increasing altitude

2 What are the four primary forces acting on an aircraft in flight?

Four forces of flight Easy
A. Thrust, gravity, torque, and pressure
B. Lift, weight, thrust, and drag
C. Weight, power, friction, and lift
D. Lift, pressure, torque, and drag

3 In steady, level flight, which force balances the aircraft's weight?

Four forces of flight Easy
A. Drag
B. Thrust
C. Lift
D. Torque

4 In steady, level flight, which force balances aerodynamic drag?

Four forces of flight Easy
A. Buoyancy
B. Thrust
C. Lift
D. Weight

5 Which equation represents translational motion according to Newton's second law?

General equation of motion Easy
A.
B.
C.
D.

6 What is the resultant force on an aircraft in unaccelerated flight?

General equation of motion Easy
A. Equal to weight
B. Equal to lift
C. Zero
D. Equal to thrust

7 How is propulsive power related to thrust and flight speed ?

Power available and power required curves Easy
A.
B.
C.
D.

8 What does an intersection of the power-available and power-required curves represent?

Power available and power required curves Easy
A. A zero-lift flight speed
B. A maximum structural speed
C. A possible steady-flight speed
D. A guaranteed stall speed

9 In steady, level flight, thrust required is equal to which aerodynamic force?

Thrust available and thrust required curves Easy
A. Weight
B. Drag
C. Side force
D. Lift

10 What does excess thrust mean?

Thrust available and thrust required curves Easy
A. Thrust available equals aircraft weight
B. Thrust required exceeds thrust available
C. Thrust required equals aircraft lift
D. Thrust available exceeds thrust required

11 How is the thrust-to-weight ratio defined?

Thrust-to-weight ratio Easy
A.
B.
C.
D.

12 What does a larger thrust-to-weight ratio generally indicate?

Thrust-to-weight ratio Easy
A. Greater wing loading
B. Greater acceleration capability
C. Higher zero-lift drag
D. Lower maximum lift

13 Which expression defines wing loading?

Wing loading Easy
A.
B.
C.
D.

14 For otherwise identical conditions, what is the usual effect of reducing wing loading?

Wing loading Easy
A. Lower stall speed
B. Higher zero-lift drag
C. Higher stall speed
D. Lower maximum lift coefficient

15 Which equation is the common parabolic drag polar?

Drag polar Easy
A.
B.
C.
D.

16 In the drag polar , what does represent?

Drag polar Easy
A. Zero-lift drag coefficient
B. Maximum lift coefficient
C. Induced-drag factor
D. Total lift coefficient

17 Which expression gives the lift-to-drag ratio?

Lift-to-drag ratio Easy
A.
B.
C.
D.

18 What does a high lift-to-drag ratio indicate?

Lift-to-drag ratio Easy
A. High aircraft weight
B. High aerodynamic efficiency
C. Low engine thrust
D. Low wing area

19 Which aerodynamic quantity normally limits the minimum steady-flight speed?

Minimum velocity Easy
A. Zero-lift drag coefficient
B. Minimum drag coefficient
C. Maximum thrust coefficient
D. Maximum lift coefficient

20 For a parabolic drag polar, what is true at maximum lift-to-drag ratio?

Aerodynamic relations associated with lift-to-drag ratio Easy
A. Parasite drag equals induced drag
B. Lift equals induced drag
C. Parasite drag becomes zero
D. Thrust equals aircraft weight

21 An aircraft maintains constant speed and a constant flight-path angle in still air. Which statement best describes its motion?

Introduction Medium
A. Its acceleration is constant and the resultant force is positive
B. Its acceleration is zero but the resultant force is nonzero
C. Its acceleration is zero and the resultant force is zero
D. Its acceleration varies while the resultant force remains zero

22 For an aircraft in steady, straight, level flight with no wind, which force balance is required?

Four forces of flight Medium
A. and
B. only
C. and
D. and

23 Using as the flight-path angle above the horizontal, the tangential equation of motion is . What relation applies during a steady climb at constant speed?

General equation of motion Medium
A.
B.
C.
D.

24 An aircraft performs a steady, straight climb at flight-path angle . Neglecting any thrust component normal to the flight path, what lift is required?

General equation of motion Medium
A.
B.
C.
D.

25 For an aircraft with a parabolic drag polar, how is the speed for minimum power required related to the speed for minimum drag ?

Power available and power required curves Medium
A.
B.
C.
D.

26 A propeller aircraft has approximately constant power available over a range of speeds. What do the two intersections of the power-available and power-required curves represent?

Power available and power required curves Medium
A. The minimum-drag and minimum-power speeds
B. The stall speed and best-glide speed
C. The climb speed and descent speed
D. The minimum and maximum steady level-flight speeds

27 For a jet aircraft whose thrust available is approximately constant with speed, what does the higher-speed intersection with the thrust-required curve indicate?

Thrust available and thrust required curves Medium
A. The minimum controllable speed
B. The minimum power speed
C. The maximum lift-to-drag speed
D. The maximum steady level-flight speed

28 An aircraft weighs and has a maximum lift-to-drag ratio of 15. What is its minimum thrust required in steady level flight?

Thrust available and thrust required curves Medium
A.
B.
C.
D.

29 An aircraft flies steadily and level at a lift-to-drag ratio of 12. What thrust-to-weight ratio is required?

Thrust-to-weight ratio Medium
A.
B.
C.
D.

30 An aircraft flies level at where air density is and . What is its wing loading ?

Wing loading Medium
A.
B.
C.
D.

31 If an aircraft's wing loading increases by while air density and remain unchanged, how does its stall speed change?

Wing loading Medium
A. It increases by
B. It decreases by
C. It decreases by
D. It increases by

32 An aircraft has the drag polar . What is when ?

Drag polar Medium
A.
B.
C.
D.

33 For the parabolic drag polar , what condition exists at maximum lift-to-drag ratio?

Drag polar Medium
A. Parasite drag is three times induced drag
B. Induced drag is twice parasite drag
C. Total drag equals induced drag
D. Induced drag equals parasite drag

34 For an aircraft with and , what lift coefficient produces maximum lift-to-drag ratio?

Lift-to-drag ratio Medium
A.
B.
C.
D.

35 A power-off aircraft glides steadily with . For a shallow glide, what is the approximate glide angle below the horizontal?

Lift-to-drag ratio Medium
A.
B.
C.
D.

36 An aircraft has , , and operates where . What is its minimum steady level-flight speed?

Minimum velocity Medium
A.
B.
C.
D.

37 An aircraft enters a coordinated level turn at a bank angle of . Compared with its wings-level stall speed, what is its stall speed in the turn?

Minimum velocity Medium
A. times as large
B. times as large
C. times as large
D. times as large

38 An aircraft has and achieves maximum at . What dynamic pressure is required for level flight at this condition?

Aerodynamic relations associated with lift-to-drag ratio Medium
A.
B.
C.
D.

39 For , which coefficient relation is true at maximum ?

Aerodynamic relations associated with lift-to-drag ratio Medium
A.
B.
C.
D.

40 For a propeller aircraft with a parabolic drag polar, what relation between induced drag and parasite drag exists at the minimum-power-required speed?

Power available and power required curves Medium
A. Induced drag is twice parasite drag
B. Parasite drag is three times induced drag
C. Induced drag is three times parasite drag
D. Induced drag equals parasite drag

41 Which flight condition is steady in the sense of having constant speed and turn rate, but is not unaccelerated in an inertial frame?

Introduction Hard
A. A straight, level trajectory with constant inertial velocity
B. A coordinated, level turn at constant airspeed
C. A straight climb at constant speed in which thrust, lift, drag, and weight have already reached force equilibrium
D. A straight glide at fixed flight-path angle and constant speed

42 An aircraft maintains steady, straight, level flight with thrust inclined upward by an angle relative to the flight path. Which force balance is correct?

Four forces of flight Hard
A. and
B. and
C. and
D. and

43 An aircraft is initially in steady flight. Thrust is instantaneously increased by along a line inclined by above the velocity vector, while all aerodynamic forces remain momentarily unchanged. What are the initial responses?

General equation of motion Hard
A. and
B. and
C. and
D. and

44 For a steady, power-off glide with flight-path angle , which relation identifies the shallowest attainable glide angle?

Four forces of flight Hard
A.
B.
C.
D.

45 A wing has , aspect ratio , and Oswald efficiency . Using and , determine the lift coefficient and lift-to-drag ratio at minimum drag.

Drag polar Hard
A. and
B. and
C. and
D. and , because induced and parasite drag coefficients are added before optimization

46 An aircraft has , , , and polar . Find the speed and drag at maximum .

Lift-to-drag ratio Hard
A. and
B. and
C. and
D. and

47 For a differentiable drag polar plotted as versus , which condition locates maximum geometrically and analytically?

Aerodynamic relations associated with lift-to-drag ratio Hard
A. , so the polar has a horizontal tangent
B. , so a line from the origin is tangent to the polar
C. , so the polar intersects a unit-slope line
D. , so the polar has a vertical tangent

48 An aircraft has , but a configuration limit restricts it to . What is the maximum attainable in this configuration?

Lift-to-drag ratio Hard
A. at
B. at
C. at
D. at

49 For level flight, , , , , and available . The low-speed thrust-limit solution is approximately . What is the actual minimum steady level-flight speed?

Minimum velocity Hard
A. , set by the thrust limit
B. , set by minimum power
C. , set by the lift limit
D. , where both limits coincide

50 A stall-limited aircraft's wing loading increases by while atmospheric density decreases to of its original value. If is unchanged, what is the ratio of the new minimum true airspeed to the original value?

Minimum velocity Hard
A.
B.
C.
D.

51 At a dynamic pressure of , an aircraft with flies level with . What thrust-to-weight ratio is required?

Thrust-to-weight ratio Hard
A.
B.
C.
D.

52 At fixed dynamic pressure and with , how does increasing wing loading affect the required thrust-to-weight ratio in level flight?

Wing loading Hard
A. The parasite term decreases and the induced term increases, so the net change depends on the initial wing loading
B. Both terms decrease, so required thrust-to-weight ratio always falls
C. The parasite term increases while the induced term remains constant
D. Both terms increase, so required thrust-to-weight ratio always increases in direct proportion to wing loading

53 A turbojet aircraft has , , , constant thrust available , and . Neglecting stall and compressibility, what are the two steady level-flight speeds?

Thrust available and thrust required curves Hard
A. and
B. and
C. and
D. and

54 At a particular altitude, the thrust-available curve is tangent to the thrust-required curve. Which interpretation is correct?

Thrust available and thrust required curves Hard
A. Minimum drag is zero because thrust available and thrust required have equal slopes
B. There is one limiting level-flight speed with zero excess thrust; a further thrust lapse eliminates level-flight equilibrium
C. The aircraft is necessarily at its stall speed with maximum excess thrust
D. There are two level-flight speeds with equal positive acceleration margins

55 A propeller aircraft has approximately constant power available over a speed range. Its horizontal power-available line intersects the power-required curve once below and once above the minimum-power speed. Which equilibrium-speed behavior is expected?

Power available and power required curves Hard
A. The lower-speed equilibrium is stable, while the higher-speed equilibrium is unstable
B. Both equilibria are stable because available power is constant
C. Both equilibria are unstable because thrust available decreases with speed
D. The lower-speed equilibrium is unstable, while the higher-speed equilibrium is stable

56 Under idealized assumptions, which pair correctly relates thrust available and power available for a fixed-shaft-power propeller and a constant-thrust turbojet?

Power available and power required curves Hard
A. Propeller: and ; turbojet: and
B. Propeller: and ; turbojet: and
C. Propeller: and ; turbojet: and
D. Propeller: both and are constant; turbojet: both increase linearly with speed

57 For in steady level flight, which set of conditions applies at minimum power required?

Power available and power required curves Hard
A. , , and
B. , , and
C. , , and
D. , , and

58 With wing area, density, and drag polar fixed, aircraft weight increases by . Assuming no aerodynamic limits intervene, how do minimum-power speed and minimum power required change?

Power available and power required curves Hard
A. Speed increases by and power increases by approximately
B. Speed increases by and power increases by approximately
C. Speed increases by and power increases by approximately
D. Speed increases by and power increases by approximately

59 For a parabolic polar, is doubled while is halved. At fixed , , and density, how do maximum , its corresponding , and its corresponding speed change?

Aerodynamic relations associated with lift-to-drag ratio Hard
A. Maximum halves, doubles, and speed remains unchanged because the product does not change
B. Maximum is unchanged, halves, and speed is multiplied by
C. Maximum doubles, is unchanged, and speed is multiplied by
D. Maximum is unchanged, doubles, and speed is multiplied by

60 At fixed dynamic pressure , an aircraft uses the polar . What wing loading minimizes the required , and what is that minimum value?

Wing loading Hard
A. and
B. and
C. and
D. and
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