Unit 3: Range And Endurance - Practice Quiz

1 For a propeller-driven airplane in steady, level flight, the engine must provide enough power primarily to overcome:

2 Fuel consumption in a propeller-driven airplane is most directly related to the:

3 Which expression represents the power required to overcome drag at airspeed ?

4 If is engine shaft power and is propeller efficiency, the useful thrust power is:

5 In the Breguet range equation, which term represents the aircraft's fuel-related weight ratio?

6 For fixed values of all other variables, increasing the ratio has what effect on Breguet range?

7 A propeller-driven airplane achieves maximum range when it operates at the condition for:

8 A propeller-driven airplane achieves maximum endurance approximately at the condition of:

9 Which aerodynamic ratio is maximized for maximum endurance of a propeller-driven airplane?

10 Fuel consumption in a jet airplane is most directly related to the:

11 In steady, unaccelerated, level flight, the thrust of a jet airplane is equal to its:

12 If is thrust-specific fuel consumption and is thrust, the fuel weight-flow rate is proportional to:

13 During steady, level flight, which force balance is used in a jet range calculation?

14 A common Breguet range equation for a jet airplane is:

15 A common Breguet endurance equation for a jet airplane is:

16 For a jet airplane at a specified altitude, maximum range is associated with maximizing:

17 A jet airplane achieves maximum endurance when it operates at the condition for:

18 For a given true airspeed, a steady headwind has what effect on an airplane's ground speed?

19 For the same fuel load and flight condition, a steady tailwind generally has what effect on ground range?

20 If is true airspeed and is the speed of a direct tailwind, the ground speed is:

21 A propeller-driven airplane flies at constant speed and drag. If propeller efficiency increases from to while specific fuel consumption remains constant, how does the fuel-flow rate change?

22 An airplane has a drag of at . If its propeller efficiency is , what shaft power must the engine provide?

23 For a propeller-driven airplane, , , , and . Using , estimate the range.

24 Assuming constant , , propeller efficiency, and power-specific fuel consumption, which expression gives the endurance of a propeller-driven airplane?

25 A propeller-driven airplane has the drag polar . Assuming constant propeller efficiency, what lift coefficient gives maximum range?

26 For a parabolic drag polar , what drag relationship applies at maximum endurance of a propeller-driven airplane?

27 A propeller-driven airplane's speed for maximum is . For a parabolic drag polar, estimate its speed for maximum endurance at the same weight and altitude.

28 A jet cruises in steady level flight with constant thrust-specific fuel consumption. If a configuration change reduces required drag by at the same flight condition, what happens to fuel-flow rate?

29 A jet requires of thrust in cruise and has . What is its fuel weight-flow rate?

30 A jet cruises at with , , and . Using the constant-speed Breguet equation, estimate its range.

31 A jet maintains while its weight decreases from to , where . If , what is its endurance?

32 For constant , , altitude, and , jet range is proportional to . If both initial and final weights are multiplied by four while their ratio remains unchanged, how does the predicted range change?

33 For a jet airplane with , what condition gives maximum endurance?

34 At the lift coefficient for maximum range of a jet airplane with a parabolic drag polar, how are parasite and induced drag related?

35 A jet's maximum-endurance speed is . Assuming a parabolic drag polar, estimate its maximum-range speed at the same weight and altitude.

36 In the constant- jet range equation, range is proportional to . If density decreases from to of its original value while other parameters remain fixed, by what factor does range change?

37 Compared with the still-air maximum-range airspeed, what adjustments generally maximize ground range in moderate steady winds?

38 An airplane flies at a true airspeed of for with a steady tailwind. Neglecting climb and descent, what ground distance does it cover?

39 An airplane maintains the same airspeed, altitude, aerodynamic configuration, and engine setting during two flights. One has a steady headwind and the other an equal tailwind. How does airborne endurance compare?

40 An airplane maintains true airspeed and the same fuel-flow rate. What is the ratio of fuel used per ground kilometre with a headwind to that with a tailwind?

41 For a propeller airplane operating with unchanged aerodynamic coefficients and weight ratio, propeller efficiency increases by 10% while power-specific fuel consumption decreases by 10%. By what factor do both ideal range and endurance change?

42 For a propeller airplane with , let maximize still-air range and maximize endurance at the same weight and altitude. Assuming neither speed is stall-limited, what is ?

43 A propeller airplane descends or slows as necessary to maintain constant , density, configuration, and propeller efficiency while fuel is consumed. When its weight becomes of its initial value, what is the ratio of its instantaneous fuel-weight flow to the initial value?

44 For steady level flight of a propeller airplane, suppose , , and and are constant. Which expression gives the instantaneous air distance per unit fuel weight?

45 A propeller airplane's weight ratio is increased from to , with , , and unchanged. What is the ratio of the new Breguet range to the original range?

46 Two constant- propeller loiter missions use the same airplane, density, , , and . Mission A decreases weight from 100 to 64 units; Mission B decreases it from 81 to 49 units. What is ?

47 A propeller airplane has and a usable limit . Which pair gives the constrained optimum lift coefficients for maximum range and maximum endurance, respectively?

48 For the nonquadratic drag polar , which conditions determine the unconstrained propeller maximum-range and maximum-endurance lift coefficients?

49 Why do the still-air maximum-endurance and maximum-range conditions differ for an ideal turbojet with constant thrust-specific fuel consumption?

50 An ideal jet maintains the same weight, , drag polar, and TSFC while moving to an altitude where density is one-quarter of its original value. Neglect compressibility and engine-altitude effects. How do endurance and range change?

51 A jet maintains constant , density, configuration, and TSFC as weight decreases. When its weight reaches , by what factor has its instantaneous still-air specific range increased?

52 Suppose a jet's TSFC varies as instead of remaining constant. At fixed weight and density, which aerodynamic quantity must be maximized for instantaneous still-air range?

53 Two ideal constant-, constant-density jet missions have identical and . Mission A changes weight from 100 to 64 units, while Mission B changes weight from 81 to 49 units. How do their ranges compare?

54 Which statement correctly distinguishes the logarithmic jet range equation from the constant-, constant-density square-root form?

55 For a jet with , let and denote the unconstrained speeds for maximum still-air range and endurance at the same weight and altitude. What is ?

56 A jet has and must satisfy . Which pair gives the constrained optimum values for maximum range and endurance, respectively?

57 For a jet with the nonquadratic polar , which pair characterizes the unconstrained maximum-range and maximum-endurance conditions?

58 For a jet, write drag as proportional to , where and is the minimum-drag speed. A headwind equals . Approximately what maximizes instantaneous ground specific range?

59 For a propeller airplane, let drag be proportional to , where . If a tailwind equals and propulsive parameters are constant, approximately what maximizes ground specific range?

60 Under the ideal assumptions that wind is steady, horizontal, and does not alter aerodynamic or engine performance, which statement about endurance and ground range is correct?