Aircraft Design - Conceptual Sketch Sizing Quiz(MCQ)

1 .

The subsequent step after the requirements in conceptual design phase is _____

A)

lofting

B)

stability

C)

control

D)

design take-off gross weight

Correct Answer : design take-off gross weight

Explanation : The Conceptual design often begins with the mission requirements of the aircraft. Once the requirements are set, next step is to estimate the design take-off gross weight. This is done due to the fact that weight will directly affect the vital performance parameters.

2 .

Design take-off gross weight includes _____

A)

only fuel weight

B)

only crew weight

C)

only payload weight

D)

crew, payload and fuel weights

Correct Answer : crew, payload and fuel weights

Explanation : Design take-off gross weight is total weight of the aircraft to be designed. It is the combination of all possible weights of an aircraft. Hence, from the given options, it is easy to say that it includes every type of weight.

3 .

A Jet transport aircraft is flying with crew load of 175kg, payload of 1400kg and fuel weight of 500kg. Find out Fuel to empty weight fraction, if design take-off gross weight of the aircraft is 5600lb.

A)

1.076

B)

0.196

C)

0.1831

D)

0.1418

Correct Answer : 1.076

Explaination : Aircraft-Design

4 .

A jet airliner aircraft is flying with crew load of 150kg, payload of 520lb and fuel weight of 500lb. Find out the empty weight if design take-off gross weight of the aircraft is given 1525lb.

A)

79lb

B)

79kg

C)

170lb

D)

355lb

Correct Answer : 79kg

Explaination : Aircraft-Design

5 .

Avionics systems are an example of ____ weight.

A)

crew

B)

payload

C)

empty

D)

passenger

Correct Answer : empty

Explanation : Crew weight is the weight of all crew members. Passenger weight includes the weight of the passenger. Empty weight will include avionics, subsystems, power plant etc…

6 .

Take-off gross weight of an aircraft is summation of _____

A)

fuel and crew weight

B)

empty and payload weight

C)

only passenger and crew weight

D)

fuel, payload, crew, empty and miscellaneous weight

Correct Answer : empty and payload weight

Explanation : Typically, take-off gross weight is the maximum possible weight of aircraft during take-off. It includes weight of crew, passenger, fuel, empty and some miscellaneous weight.

7 .

What is the typical range for empty weight fraction?

A)

0.3-0.7

B)

0.1-0.125

C)

0.14-0.28

D)

0.25-0.27

Correct Answer : 0.3-0.7

Explanation : Empty weight fraction has typical range from 0.3-0.7 according to historical guidelines. Higher empty weight fraction indicates more weight. The range given is based on typical guideline and hence in some cases it can go beyond 0.7 as well.

8 .

Which of the following pair is correct based on the empty weight fraction?

A)

Flying boat-0.3, Jet trainer-1.0

B)

Flying boat-0.77, Jet trainer-0.65

C)

Flying boat-0.45, Jet trainer-0.65

D)

Flying boat-0.65, Jet trainer-0.77

Correct Answer : Flying boat-0.77, Jet trainer-0.65

Explanation : Here, we need to think logically. The flying boat has more empty weight than the typical jet trainer aircraft. A flying boat needs to carry additional load of boat hull compare to a typical jet trainer aircraft.

9 .

A military Aircraft should be designed to have ______

A)

empty weight fraction unity

B)

highest possible empty weight fraction

C)

lowest possible empty weight fraction

D)

empty weight fraction higher than 0.89

Correct Answer : lowest possible empty weight fraction

Explanation : One of the most important and crucial requirements of military aircraft is minimum possible weight. The lower the weight lesser the drag and lesser the thrust requirement. Hence, a military aircraft should as lightest as possible.

10 .

Determine the corrections or otherwise of the following assertion [A] and reason [R]:
Assertion [A]: Flying boats have higher values of empty weight fraction than that of the military aircraft.
Reason[R]: Military aircraft has to be lighter in weight.

A)

Both [A] and [R] are true and [R] is the correct reason for [A]

B)

Both [A] and [R] are true but [R] is not the correct reason for [A]

C)

[A] is true but [R] is false

D)

[A] is false but [R] is true

Correct Answer : [A] is false but [R] is true

Explaination : Military aircraft has to be lighter in weight is true. Flying boats are heavier than that of the typical military aircraft. The reason behind it is that flying boat has to carry extra weight of hull. Hence, [A] and [R] both correct but [R] is not the correct reason for given assertion.

11 .

The design take-off gross weight of aircraft is given by _____

A)

W₀ = W_crew + W_payload + W_fuel * W_empty

B)

W₀ = W_crew + W_payload + W_fuel – W_empty

C)

W₀ = W_crew + W_payload + W_fuel + W_empty

D)

W₀ = W_crew + W_payload – W_fuel – W_empty

Correct Answer : W₀ = W_crew + W_payload + W_fuel + W_empty

Explaination : The design take-off gross weight is the total weight of the aircraft. It consists of every possible segments either it is payload or fuel. Hence, it can be seen as the addition of the all possible weight in an aircraft.

12 .

Aircraft fuel weight does not include reserved fuel fraction.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

Explanation : The total fuel carried by aircraft consists of usable fuel and reserved fuel. Useable fuel is provided for completing a particular mission. Reserved fuel is for an emergency.

13 .

Total fuel weight of aircraft is ______

A)

mission fuel only

B)

reserved fuel only

C)

sum of trapped and mission fuel

D)

sum of mission fuel, reserve fuel and trapped fuel

Correct Answer : sum of mission fuel, reserve fuel and trapped fuel

Explanation : The fuel weight of aircraft is sum of useable mission fuel, reserved fuel and trapped fuel. Mission fuel is the actual useable fuel for the respective mission. Trapped fuel is unusable fuel which has been trapped in supply lines or which cannot be used.

14 .

Choose the correct statement based on fuel weight.

A)

Fuel weight is independent of SFC of engine

B)

Fuel required is solely based on mission profile

C)

Fuel requirement is not affected by any factors

D)

The required amount of the fuel for mission depends on aerodynamics, SFC, mission itself etc

Correct Answer : The required amount of the fuel for mission depends on aerodynamics, SFC, mission itself etc

Explanation : Total aircraft fuel requirement does not solely depend on mission profile. Fuel weight for mission depends on number of factors such as mission profile, aerodynamics, SFC of engine etc.

15 .

Mission leg fuel fraction is defined by _____

A)

weight at end of the phase to that of at the begin

B)

weight of phase at the begin

C)

weight at end of the phase

D)

weight at end of the phase to that of at the begin

Correct Answer : weight at end of the phase to that of at the begin

Explanation : Mission leg is nothing but the individual mission segment or phase. Mission leg fuel fraction is weight of the fuel at end of the phase to that of at beginning of that mission leg.

16 .

Determine the corrections or otherwise of the following assertion [A] and reason [R]:
Assertion [A]: Fuel consumption is more for low level, high speed flight mission.
Reason[R]: At low altitude, the aerodynamic efficiency decreases drastically which affects the engine efficiency and range as well. To maintain cruise flight more fuel consumption is required.

A)

[A] is true but [R] is false

B)

[A] is false but [R] is true

C)

Both [A] and [R] are true and [R] is the correct reason for [A]

D)

Both [A] and [R] are true but [R] is not the correct reason for [A]

Correct Answer : Both [A] and [R] are true and [R] is the correct reason for [A]

Explaination : The low-level strike mission has to fly at just few km off the ground. During such flight the L/D ratio – aerodynamic efficiency is reduced in drastic manner. Since flight needs to be at higher velocity more thrust will be required. This will increase fuel consumption as compare to high altitude flight. Hence, both [A] and [R] are true and [R] is the correct reason for [A].

17 .

A jet transport aircraft has fuel storage of 1200kg. It has completed taxi phase and preparing for take-off. At the end of the taxing, it has fuel fraction of 0.98. Determine how much fuel is available after taxing. Given take-off gross weight is 9000kg.

A)

2240lb

B)

1800kg

C)

1020kg

D)

180kg

Correct Answer : 1020kg

Explaination : Aircraft take-off gross weight W₀ = 9000kg, Fuel storage = 1200kg
Fuel weight fraction after taxi = W_taxi/W₀ = 0.98
Here, there is no provision of reserved fuel is mentioned so, we are neglecting reserve fuel fraction.
Now, from fuel fraction method,
Used fuel weight fraction is W_f / W₀ = 1 – (W_taxi/W₀)
= 1 – 0.98 = 0.02
Hence, fuel used during taxing mission = W_f = W₀ * 0.02 = 180kg.
Now, remaining fuel weight = fuel storage – fuel used during taxi
= 1200 – 180 = 1020kg.

18 .

The typical method for determining fuel weight used is called as _____

A)

fuel interpolation

B)

fuel-fraction method

C)

fuel-invert method

D)

fuel fraction mining

Correct Answer : fuel-fraction method

Explanation : Fuel- fraction method is a simple method for estimating fuel fraction of the aircraft. It is the most commonly used method due to the simplicity of calculations.

19 .

What is the working principle of 'fuel-fraction' method?

A)

Assuming any value for fuel fraction

B)

Calculating fuel fraction for each stage

C)

Division of mission profile into 3 phases only

D)

Division of mission profile into number of phases and finding individual phase fuel fraction

Correct Answer : Division of mission profile into number of phases and finding individual phase fuel fraction

Explanation : The fuel fraction method is mostly used method for fuel weight fraction. This is very simple method in which we divide whole mission profile into number of mission phases. After that we calculate individual mission segment weight fraction. And based on which we determine approximated fuel weight.

20 .

In A/C, we provide reserve fuel for _____

A)

weight reduction

B)

to increase weight

C)

loiter maneuver

D)

there is no provision for it

Correct Answer : loiter maneuver

Explanation : Every aircraft has a particular mission profile to follow. Fuel requirement are based on it. In some cases, aircraft need to loiter for more time. If some additional fuel is nor provided then, in such cases aircraft will not be able to perform any additional loiter. Hence, for such cases and also for emergencies we provide reserved fuel.

21 .

According to FAA, general aviation aircraft requires reserved fuel in terms of _____

A)

additional cruise fuel of half hour

B)

additional climb fuel

C)

no provision is mentioned in FAA

D)

additional taxi-way fuel of three hours

Correct Answer : additional cruise fuel of half hour

Explanation : For a typical aircraft, it is mandatory to carry reserved fuel. This reserved fuel can be utilized at the time of emergency. According to FAA regulation, for general aviation category we need to provide additional cruise fuel so that it can be used to improve endurance by half hour.

22 .

A prop-driven aircraft is cruising with 90% propeller efficiency. If, range of aircraft is 7*10⁶ ft, C=1.38*10^-7 s^-1 and L/D = 14 then what will be the fuel weight fraction for the cruise?

A)

0.9216

B)

0.9261

C)

0.9289

D)

0.9365

Correct Answer : 0.9261

23 .

If all the other factors remain unchanged and only aerodynamic efficiency of the aircraft is doubled then, what will be the cruise segment fuel weight fraction?

A)

Will decrease

B)

Will increase

C)

Will remain same

D)

Will be independent of aerodynamic efficiency

Correct Answer : Will increase

24 .

How will you determine climb mission weight fraction?

A)

Loiter

B)

Cruise Speed

C)

Always constant

D)

Climb Endurance

Correct Answer : Climb Endurance

Explanation : Climb phase usually measured by rate of climb. Climb endurance formula is used to determine the endurance of aircraft at climb phase. Typically we can find climb weight fraction from historic time line however in some cases we can also use climb endurance formula to determine fuel fraction.

25 .

What does the following diagram represents?
Aircraft-Design

A)

Bomber mission

B)

Penetration strike

C)

Accelerated cruise

D)

Simple cruise mission profile

Correct Answer : Simple cruise mission profile

Explaination : The diagram is representing altitude vs time relation. It is also called ‘mission profile’ of an aircraft. This mission profile consist only basic phases of flight. Hence, it can be termed as simple cruise mission profile.

26 .

Which of the following is part of the fuel-fraction method?

A)

Developing lofting

B)

Finding volume ratio

C)

Empty weight fraction

D)

Calculating individual mission segment weight fraction

Correct Answer : Calculating individual mission segment weight fraction

Explanation : Lofting is a vital part of preliminary design phase. The fuel fraction method is very simple and basic approximation method. Here, mission profile is divided and then for every individual phase we calculate mission segment weight fraction.

27 .

Choose appropriate option for cruise mission leg weight fraction.

A)

Cruise invert method

B)

Breguet approximation

C)

Breguet range formula

D)

Breguet endurance formula

Correct Answer : Breguet range formula

Explanation : Breguet endurance formula is used to determine the endurance of aircraft. Range formula is used to calculate range for respective mission. In simple sizing method we consider that the cruise is ending with descent. Also, we assume that cruise range has accounted for descent as well. Hence, we use range formula to determine fuel fraction.

28 .

An Aircraft has gross weight of 10000lb. At the end of the mission segment it has weight fraction as 0.985. Determine fuel consumed for this mission.

A)

150lb

B)

150kg

C)

60lb

D)

60kg

Correct Answer : 150lb

Explaination : Aircraft gross weight W₀ = 10000lb
Fuel weight fraction at the end of mission = W_x/W₀ = 0.985
Here, there is no provision of reserved fuel is mentioned. So, we are neglecting reserve fuel fraction.
Now, from fuel fraction method,
Used fuel weight fraction is W_f / W₀ = 1 – (W_x / W₀)
= 1 – 0.985 = 0.015
Hence, fuel consumed during this mission = W_f = W₀ * 0.015 = 10000 * 0.015 = 150lb.

29 .

What will be the total fuel weight fraction for x-number of mission phases?

A)

W_f / W₀ = 1 + (W_x / W₀)

B)

W_f / W₀ = 1 – (W_x / W₀)

C)

W_f / W₀ = 1 + (W_x / W₀)

D)

W_f / W₀ = 1 / (W_x / W₀)

Correct Answer : W_f / W₀ = 1 – (W_x / W₀)

Explaination : The fuel-fraction method is used to determine total fuel weight fraction.
According to which if there are x – number of mission phases in mission profile then the total fuel weight fraction is given by,
W_f / W₀ = 1 – (W_x / W₀)
Since, reserved fuel is not mentioned we can neglect it.

30 .

Which of the following is part of take-off weight estimation?

A)

Lofting

B)

Drafting

C)

Manufacturing part is first step

D)

Initial guess of take-off gross weight based on mission specifications

Correct Answer : Initial guess of take-off gross weight based on mission specifications

Explanation : Lofting is definition of skin. Drafting is related to drawing. Based mission specification, crew and payload weight is determined. After which next step is to make an initial guess of take-off gross weight.

31 .

What is the first step to estimate the gross weight W0?

A)

To find crew and payload weight so initial W0 can be guess

B)

Drafting

C)

To find proper lofting

D)

Directly finding take-off distance

Correct Answer : To find crew and payload weight so initial W0 can be guess

Explanation : Take-off gross weight is determined in stepwise manner. It is an iterative process in which we first find weight of crew, passenger, payloads etc. After which next step is to guess gross weight based on crew and payload weight.

32 .

Keeping all other factors constant if only range of aircraft is increased then, what will be effect on the gross weight of aircraft?

A)

Unchanged

B)

Gross weight will increase

C)

Will decrease

D)

Not depended on range

Correct Answer : Gross weight will increase

33 .

An aircraft has Crew and payload of 180kg. It has empty weight fraction of 0.48 and fuel weight is 0.7 times empty weight. What will be the gross weight of aircraft?

A)

215kg

B)

950kg

C)

1000lb

D)

2157lb

Correct Answer : 2157lb

Explanation : Given crew and payload = 180kg,
Empty weight fraction W_e / W₀ = 0.48
Fuel weight is 0.7 times empty weight.
Hence, W_f = 0.7*W_e
Hence, W_f / W₀ = 0.7*W_e / W₀ = 0.7*0.48 = 0.336
Gross weight of aircraft is,
W₀ = W_crew + W_payload + W_fuel + W_empty
By re-arranging,
W₀ = W_crew + W_payload / [1 – (W_f/ W₀) – (W_e / W₀)]
= 180 / [1-0.336-0.48] = 978.26kg = 2157.06lb.

34 .

Total take-off gross weight depends on _____

A)

independent

B)

fuel consumption only

C)

fuel, crew, payload and empty weight

D)

only on aerodynamic efficiency

Correct Answer : fuel, crew, payload and empty weight

Explanation : Total take-off gross weight is nothing but the sum of all the possible aspects of an aircraft. Hence, it will depend on fuel weight, crew and payload weight and also on empty weight.

35 .

Following diagram is showing mission profile with different phases with mission segment fuel fraction as shown. If crew weight is 150kg, payload of 600kg and empty fraction of 0.495. Determine gross weight of the aircraft.
Aircraft-Design

A)

4431lb

B)

38910lb

C)

4430kg

D)

39810kg

Correct Answer : 4430kg

Explaination : Given crew weight = 150kg, payload weight = 600kg
Fuel weight fraction W_f / W₀ = 1.06[1 – W_x/W₀],
Now from fuel fraction method,
W_x / W₀ = multiplication of each phase fraction
= 0.975*0.98*0.96*0.8*0.96*0.97
= 0.6833
Now,
W_f / W₀ = 1.06 * [1 – (W_x / W₀)] = 0.3357
Empty weight fraction W_e / W₀ = 0.481
Gross weight of aircraft is,
W₀ = W_crew + W_payload + W_fuel + W_empty
By re-arranging,
W₀ = W_crew + W_payload / [1 – (W_f/ W₀) – (W_e / W₀)]
= 150 + 600 / [1-0.3357-0.495] = 4430kg