CDC 2a651s Volume 2 By CDCmaster

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  • 1/88 Questions

    What is the general flow of gases from the combustion chamber?

    • At right angles to the rotor shaft
    • Parallel to the axis of the rotor shaft
    • At the same velocity as the rotor shaft
    • In a reverse direction from the rotor shaft
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About This Quiz

Explore the fundamentals of motion and energy in aviation with the 'CDC 2A651s Volume 2 by CDCmaster' quiz. Dive into Newton's laws, Bernoulli's principle, and energy concepts, crucial for understanding aircraft dynamics and engineering.

CDC 2a651s Volume 2 By CDCmaster - Quiz

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  • 2. 

    Of the following, the recommended method of expanding a bearing race before installation is to use a

    • Hot-oil bath

    • Coal furnace

    • Hydraulic-oil bath

    • Oscillating heater

    Correct Answer
    A. Hot-oil bath
    Explanation
    The recommended method of expanding a bearing race before installation is to use a hot-oil bath. This method involves heating the bearing race in a bath of hot oil, which causes the metal to expand and become easier to install. The hot oil provides even and controlled heating, ensuring that the race expands uniformly and avoids any damage or distortion. This method is commonly used in industrial settings for efficient and accurate installation of bearing races.

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  • 3. 

    On an F100-PW-220 engine, the total temperature (Tt2) sensor sends electronic signals to the

    • N1 sensor

    • Engine fuel control

    • Digital electronic engine control (DEEC)

    • Compressor intermediate case (CIVV)

    Correct Answer
    A. Digital electronic engine control (DEEC)
    Explanation
    The total temperature (Tt2) sensor on an F100-PW-220 engine sends electronic signals to the Digital electronic engine control (DEEC). The DEEC is responsible for monitoring and controlling various engine parameters, including fuel flow and engine performance. By receiving signals from the Tt2 sensor, the DEEC can accurately measure the total temperature of the engine and make necessary adjustments to optimize engine operation and fuel efficiency.

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  • 4. 

    What does fuel for an engine represent?

    • Available horsepower

    • Thrust produced

    • Potential energy

    • Efficiency ratio

    Correct Answer
    A. Potential energy
    Explanation
    Fuel for an engine represents potential energy. Potential energy is the stored energy that can be converted into other forms of energy, such as mechanical energy in the case of an engine. Fuel contains chemical potential energy, which is released through combustion to produce energy that can be used to power the engine. Therefore, the fuel in an engine represents the potential energy that can be harnessed to perform work.

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  • 5. 

    To measure barometric pressure, you would use a

    • Potentiometer

    • Psychrometer

    • Pyrometer

    • Barometer

    Correct Answer
    A. Barometer
    Explanation
    A barometer is used to measure barometric pressure, which is the pressure exerted by the atmosphere. It is specifically designed for this purpose and provides accurate readings of atmospheric pressure. A potentiometer is an electrical component used to measure and control voltage, so it is not suitable for measuring barometric pressure. A psychrometer is used to measure relative humidity, not barometric pressure. A pyrometer is used to measure high temperatures, such as in industrial processes, and is not designed for measuring barometric pressure. Therefore, the correct answer is barometer.

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  • 6. 

    Where is the highest point of temperature reached in an engine?

    • Tailpipe

    • Exhaust cone

    • Turbine section

    • Combustion section

    Correct Answer
    A. Combustion section
    Explanation
    The highest point of temperature in an engine is reached in the combustion section. This is where the fuel and air mixture is ignited and burned, resulting in a rapid increase in temperature and pressure. The combustion section is designed to withstand these extreme temperatures and pressures, and it is where the energy is generated to power the engine.

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  • 7. 

    Before inspecting new jet engine bearings, you should

    • Separate the halves

    • Perform a spin check

    • Apply a preservative

    • Remove the preservative

    Correct Answer
    A. Remove the preservative
    Explanation
    Before inspecting new jet engine bearings, it is necessary to remove the preservative. This is important because the preservative is applied to protect the bearings during storage and transportation. However, it can interfere with the inspection process and potentially affect the performance of the bearings if not removed. Therefore, removing the preservative ensures that the bearings can be properly inspected for any potential issues or defects before they are installed in the jet engine.

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  • 8. 

    Before you install separable bearings, you must ensure the

    • Rollers are serviceable

    • Bearings are a matched set

    • Rollers are properly positioned

    • Parts are positioned and serviceable

    Correct Answer
    A. Bearings are a matched set
    Explanation
    To install separable bearings, it is crucial to ensure that the bearings are a matched set. This means that the bearings should have the same dimensions, load capacity, and design specifications. Using mismatched bearings can lead to uneven load distribution, premature wear, and potential failure of the bearing system. Therefore, it is essential to carefully check and confirm that the bearings being installed are a matched set to guarantee proper functioning and longevity of the bearing system.

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  • 9. 

    When discussing a jet engine and the location of its parts, you must always do so as if you were standing at the

    • Rear of engine

    • Front of engine

    • Left side of engine

    • Right side of engine

    Correct Answer
    A. Rear of engine
    Explanation
    When discussing the location of parts in a jet engine, it is important to refer to them from the perspective of standing at the rear of the engine. This means that when describing the position of various components, they are referenced based on their location relative to the observer standing at the back of the engine.

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  • 10. 

    On an F100-PW-220 engine, the leading edge vanes are hollow

    • To save weight

    • For better aerodynamics

    • To allow for variable movement

    • So that anti-icing air can flow through them

    Correct Answer
    A. So that anti-icing air can flow through them
    Explanation
    The leading edge vanes on an F100-PW-220 engine are hollow so that anti-icing air can flow through them. This is important because during flight, ice can accumulate on the leading edge of the engine, which can disrupt the airflow and potentially cause engine failure. By allowing anti-icing air to flow through the hollow vanes, the engine is able to prevent ice buildup and maintain optimal performance.

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  • 11. 

    What drives the inlet fan module (IFM) in the F119-PW-100 engine?

    • Gearbox assembly

    • Core engine module

    • Low-pressure turbine (LPT) module

    • High-pressure turbine (HPT) assembly

    Correct Answer
    A. Low-pressure turbine (LPT) module
    Explanation
    The correct answer is the Low-pressure turbine (LPT) module. The LPT module drives the inlet fan module (IFM) in the F119-PW-100 engine. The LPT module is responsible for extracting energy from the high-velocity exhaust gases and using it to drive the fan module, which provides the necessary airflow for the engine's operation. This allows the engine to generate thrust and power the aircraft.

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  • 12. 

    Which section of a jet engine introduces and burns fuel?

    • Turbine

    • Diffuser

    • Compressor

    • Combustion

    Correct Answer
    A. Combustion
    Explanation
    The section of a jet engine that introduces and burns fuel is called the combustion section. In this section, fuel is mixed with compressed air and ignited, creating a high-temperature and high-pressure environment. The combustion process releases energy in the form of hot gases, which then flow through the turbine section to generate thrust. The combustion section is crucial for the operation of a jet engine as it provides the necessary power to propel the aircraft forward.

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  • 13. 

    When two or more turbine wheels are used in a jet engine, which component is placed directly in front of each turbine wheel?

    • Diffuser

    • Jet nozzle

    • Combustion chamber

    • Turbine stator (nozzle diaphragm)

    Correct Answer
    A. Turbine stator (nozzle diaphragm)
    Explanation
    When two or more turbine wheels are used in a jet engine, the component that is placed directly in front of each turbine wheel is the turbine stator (nozzle diaphragm). The turbine stator helps to direct the flow of exhaust gases onto the turbine blades, ensuring efficient energy transfer from the high-pressure gases to the turbine. It also helps to maintain a uniform flow of gases and prevent turbulence, which can affect the performance of the turbine wheels.

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  • 14. 

    A turbo-supercharger is essentially a

    • Jet engine

    • High-capacity air pump

    • Temperature reduction device

    • High-volume air direction device

    Correct Answer
    A. High-capacity air pump
    Explanation
    A turbo-supercharger is a device that increases the amount of air flowing into an engine, thereby increasing its power output. It achieves this by using a turbine to harness the exhaust gases from the engine and drive a compressor, which compresses the incoming air before it enters the engine. This compressed air allows for more fuel to be burned, resulting in increased power. Therefore, a turbo-supercharger can be described as a high-capacity air pump, as it significantly boosts the amount of air supplied to the engine.

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  • 15. 

    Fuel that accumulates after a failed start is

    • Drained overboard by a drain system

    • Returned to the fuel control by tubes

    • Burned on the next start attempt

    • Allowed to evaporate

    Correct Answer
    A. Drained overboard by a drain system
    Explanation
    After a failed start, the fuel that accumulates is drained overboard by a drain system. This is necessary to prevent any potential hazards or damage that could occur if the fuel were to remain in the system. By draining the fuel overboard, it ensures that the fuel is safely removed from the system and does not interfere with future start attempts.

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  • 16. 

    Next to contamination and improper lubrication, what is the greatest enemy of antifriction bearings?

    • Dirt

    • Heat

    • Improper removal

    • Using wrong type of oil

    Correct Answer
    A. Improper removal
    Explanation
    Improper removal refers to the incorrect or careless removal of the antifriction bearings from their designated positions. This can lead to damage or misalignment of the bearings, causing them to function improperly or fail altogether. Improper removal can include using excessive force, using incorrect tools, or not following the proper procedure for removal. Therefore, improper removal can be considered as a significant enemy of antifriction bearings, as it can greatly reduce their lifespan and efficiency.

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  • 17. 

    Which component on an F100-PW-220 engine sends a signal to drive the primary actuator flexible shaft?

    • Stator generator

    • Unified Control (UC)

    • Electronic engine control (EEC)

    • Convergent exhaust nozzle control (CENC)

    Correct Answer
    A. Convergent exhaust nozzle control (CENC)
    Explanation
    The component on an F100-PW-220 engine that sends a signal to drive the primary actuator flexible shaft is the Convergent exhaust nozzle control (CENC). This component is responsible for controlling and adjusting the position of the exhaust nozzle, which affects the engine's thrust and performance. By sending a signal to the primary actuator flexible shaft, the CENC ensures that the nozzle is positioned correctly to optimize engine operation. The other options, such as the stator generator, Unified Control (UC), and Electronic engine control (EEC), are not directly involved in driving the primary actuator flexible shaft.

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  • 18. 

    In addition to the augmenter, what is the other major assembly on the F119-PW-100 engine

    • Nozzle

    • Gearbox

    • Low pressure turbine

    • High pressure turbine

    Correct Answer
    A. Gearbox
    Explanation
    The other major assembly on the F119-PW-100 engine, in addition to the augmenter, is the gearbox. The gearbox is an essential component that helps transfer power from the engine to various systems, such as generators or hydraulic pumps. It is responsible for ensuring the correct speed and torque are delivered to these systems, allowing them to function properly. Without a gearbox, the engine's power output would not be effectively utilized, leading to inefficiencies and potential damage to other components.

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  • 19. 

    Newton's third law of motion explains why an operating jet engine produces

    • Forward thrust

    • Forward acceleration

    • Increased acceleration

    • Decreased acceleration

    Correct Answer
    A. Forward thrust
    Explanation
    Newton's third law of motion states that for every action, there is an equal and opposite reaction. In the case of an operating jet engine, the action is the expulsion of high-speed exhaust gases backward. As a result of this action, there is an equal and opposite reaction, which is the forward thrust generated by the engine. Therefore, the correct answer is forward thrust.

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  • 20. 

    "The combination of decreased pressure above an airfoil, and the increased pressure below the airfoil produces lift" is best described by

    • Bernoulli's principle

    • Newton's first law of motion

    • Newton's second law of motion

    • Newton's third law of motion

    Correct Answer
    A. Bernoulli's principle
    Explanation
    The statement describes how the pressure difference above and below an airfoil creates lift. According to Bernoulli's principle, as the speed of a fluid (in this case, air) increases, its pressure decreases. When air flows over the curved upper surface of an airfoil, it speeds up, resulting in decreased pressure. At the same time, the air flowing underneath the airfoil is slower, causing increased pressure. This pressure difference creates lift, allowing the airfoil (such as an airplane wing) to generate upward force and stay in the air.

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  • 21. 

    The percentage of combustion efficiency of a gas turbine is usually between

    • 60 and 70

    • 65 and 75

    • 75 and 95

    • 95 and 100

    Correct Answer
    A. 95 and 100
    Explanation
    The percentage of combustion efficiency of a gas turbine is usually between 95 and 100 because gas turbines are designed to be highly efficient in converting the energy from the combustion process into mechanical energy. A combustion efficiency of 95 to 100 percent indicates that almost all of the fuel is being fully burned and converted into useful work, resulting in minimal waste and maximum energy output. This high level of efficiency is desirable in order to maximize the performance and cost-effectiveness of gas turbine systems.

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  • 22. 

    What is the most common type of fuel nozzle system

    • Pressure-atomizing

    • Fuel-blasting

    • Fuel ejector

    • Fuel tube

    Correct Answer
    A. Pressure-atomizing
    Explanation
    The most common type of fuel nozzle system is the pressure-atomizing system. This system uses high pressure to atomize the fuel into fine particles, allowing for efficient combustion. It is widely used in various industries, including aviation and power generation, due to its ability to provide a fine spray of fuel for optimal combustion efficiency.

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  • 23. 

    The purpose of an augmentor (afterburner) in a jet engine is to

    • Augment the maximum thrust capability of the basic engine

    • Increase engine revolutions per minute (rpm)

    • Increase exhaust gas temperature (EGT)

    • Reduce pressure drop

    Correct Answer
    A. Augment the maximum thrust capability of the basic engine
    Explanation
    The purpose of an augmentor (afterburner) in a jet engine is to increase the maximum thrust capability of the basic engine. The augmentor achieves this by injecting additional fuel into the exhaust stream and igniting it, which increases the temperature and velocity of the exhaust gases. This increased energy output results in a higher thrust output, allowing the jet engine to produce more power and achieve greater performance.

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  • 24. 

    When you handle jet engine bearings, you must change cotton gloves frequently because they

    • Attract dirt

    • Wear faster

    • Cause oxidation

    • Get soaked with sweat

    Correct Answer
    A. Get soaked with sweat
    Explanation
    When handling jet engine bearings, it is necessary to change cotton gloves frequently because they get soaked with sweat. This is important because sweat can cause the gloves to become wet and damp, which can compromise their effectiveness in providing a protective barrier. Additionally, wet gloves can also lead to discomfort and reduced dexterity, making it necessary to change them regularly to maintain optimal performance and safety.

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  • 25. 

    One advantage of the modular design concept is that it eliminates the need to

    • Keep spare engines

    • Keep spare modules

    • Return the modules to depot for overhaul

    • Return whole engines to depot for overhaul

    Correct Answer
    A. Return whole engines to depot for overhaul
    Explanation
    The modular design concept allows for individual components or modules to be easily replaced or repaired, eliminating the need to return whole engines to the depot for overhaul. This means that instead of having to take out an entire engine for maintenance, only the faulty module needs to be addressed, reducing downtime and costs associated with engine maintenance.

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  • 26. 

    Which section of a jet engine continually supplies air and maintains pressure?

    • Turbine

    • Diffuser

    • Compressor

    • Combustion

    Correct Answer
    A. Compressor
    Explanation
    The compressor section of a jet engine continually supplies air and maintains pressure. It is responsible for compressing the incoming air before it enters the combustion chamber. This compressed air is then mixed with fuel and ignited to create the necessary thrust for the jet engine. Without the compressor, the air would not be at the required pressure for efficient combustion and propulsion.

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  • 27. 

    How many British thermal units (Btu) does the heat content per pound of kerosene produce? 

    • 10500

    • 15000

    • 18500

    • 40000

    Correct Answer
    A. 18500
    Explanation
    Kerosene has a heat content of 18,500 British thermal units (Btu) per pound. This means that when one pound of kerosene is burned, it releases 18,500 Btu of heat energy.

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  • 28. 

    What effect does moisture content or humidity have on density of air?

    • More moisture, more dense

    • More moisture, less dense

    • Less moisture, less dense

    • None

    Correct Answer
    A. More moisture, less dense
    Explanation
    When there is more moisture in the air, it displaces some of the dry air molecules, leading to a decrease in the overall density of the air. This is because water molecules are lighter than the average molecular weight of dry air, which is mostly composed of nitrogen and oxygen. Therefore, the presence of more moisture in the air causes it to become less dense.

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  • 29. 

    What is the most probable cause of a flameout of a jet engine flying at 40,00 feet with a constant engine revolutions per minute (rpm) of 50 percent?

    • The rpm is too low

    • A decrease in barometric pressure

    • The failure of the breather pressurizing valve

    • Excessive ducting of air from the compressor into the combustion chamber

    Correct Answer
    A. The rpm is too low
    Explanation
    The most probable cause of a flameout of a jet engine flying at 40,000 feet with a constant engine RPM of 50 percent is that the RPM is too low. When the RPM is low, it can lead to insufficient fuel-air mixture in the combustion chamber, resulting in a flameout. This can happen especially at higher altitudes where the air is thinner and requires a higher RPM to maintain proper combustion.

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  • 30. 

    Three types of turbine and vane assemblies used in jet engines are impulse, reaction, and

    • Fir tree

    • Shrouded

    • Unshrouded

    • Reaction-impulse

    Correct Answer
    A. Reaction-impulse
    Explanation
    The correct answer is "reaction-impulse". This answer refers to a combination of both reaction and impulse turbine and vane assemblies used in jet engines. A reaction turbine uses the principle of Newton's third law of motion, where the change in momentum of the fluid produces a force on the turbine blades. An impulse turbine, on the other hand, uses the principle of Newton's second law of motion, where the change in momentum of the fluid produces a change in velocity of the fluid, resulting in a force on the turbine blades. The reaction-impulse turbine and vane assembly combines both of these principles to optimize the efficiency and performance of the jet engine.

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  • 31. 

    The most commonly used bearing removal tools include

    • Drift pipes and hammers

    • Drift pipes and arbor presses

    • Bearing pullers and hammers

    • Arbor presses and bearing pullers

    Correct Answer
    A. Arbor presses and bearing pullers
    Explanation
    Arbor presses and bearing pullers are commonly used tools for removing bearings. Arbor presses provide a controlled and precise force to push the bearing out of its housing, while bearing pullers are designed to grip onto the bearing and pull it out. These tools are preferred over hammers and drift pipes as they minimize the risk of damaging the bearing or the surrounding components during removal.

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  • 32. 

    On an F100-PW-220 engine, which stage of compression provides anti-icing air for the engine inlet?

    • Sixth

    • Seventh

    • Twelfth

    • Thirteenth

    Correct Answer
    A. Thirteenth
    Explanation
    The thirteenth stage of compression provides anti-icing air for the engine inlet on an F100-PW-220 engine.

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  • 33. 

    On an F100-PW-220 engine, the gearbox module is driven by the rear compressor through

    • A radial drive shaft

    • An axial drive shaft

    • A gearbox drive shaft

    • A transfer drive shaft

    Correct Answer
    A. A gearbox drive shaft
    Explanation
    The correct answer is "a gearbox drive shaft". In an F100-PW-220 engine, the gearbox module is driven by a gearbox drive shaft, which transfers power from the rear compressor to the gearbox. This drive shaft is specifically designed for the purpose of driving the gearbox module, ensuring efficient power transmission and operation of the engine.

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  • 34. 

    Where is the gearbox mounted on the F119-PW-100 engine and what drives it?

    • 6 o'clock position front fan ducts; fan module

    • 6 o'clock position intermediate case; core module

    • 6:30 o'clock position lower fan case; core module

    • 6:30 o'clock position compressor inlet case: fan module

    Correct Answer
    A. 6 o'clock position intermediate case; core module
    Explanation
    The gearbox on the F119-PW-100 engine is mounted at the 6 o'clock position on the intermediate case, which is part of the core module.

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  • 35. 

    Which type of defect appears on bearings as a result of bearing parts striking together?

    • Nicks

    • Galling

    • Grooves

    • Scratches

    Correct Answer
    A. Nicks
    Explanation
    Nicks are a type of defect that appears on bearings as a result of bearing parts striking together. When two parts of a bearing come into contact with each other, it can cause small chips or nicks to form on the surface. These nicks can lead to further damage and affect the overall performance and lifespan of the bearing. Galling, grooves, and scratches are also types of defects that can occur on bearings, but in this case, the correct answer is nicks.

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  • 36. 

    Excessive bearing wear can usually be detected by

    • Pits

    • Bands

    • Misalignment

    • Roughness of the metal

    Correct Answer
    A. Roughness of the metal
    Explanation
    Excessive bearing wear can usually be detected by the roughness of the metal. This is because as the bearing wears down, the metal surface becomes rough and uneven. This roughness can be felt when touching the bearing or observed visually. It indicates that the bearing is no longer smooth and is experiencing excessive wear, which can lead to reduced performance and potential failure. Pits, bands, and misalignment can also be signs of bearing wear, but the roughness of the metal is a more reliable indicator in most cases.

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  • 37. 

    On which module of an F100-PW-220 engine is the stator generator mounted?

    • Core

    • Inlet fan

    • Gearbox

    • Augmenter

    Correct Answer
    A. Gearbox
    Explanation
    The stator generator of an F100-PW-220 engine is mounted on the gearbox. The gearbox is an essential component of the engine that transfers power from the core to other parts of the engine, such as the fan and augmenter. Mounting the stator generator on the gearbox allows it to efficiently generate electricity and contribute to the overall functioning of the engine.

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  • 38. 

    How many stages are in the inlet fan module of the F119-PW-100 engine?

    • Two

    • Three

    • Four

    • Five

    Correct Answer
    A. Three
    Explanation
    The correct answer is Three. In the inlet fan module of the F119-PW-100 engine, there are three stages. Each stage consists of a set of rotating blades and stationary vanes that help to compress the incoming air and direct it towards the combustion chamber. These stages work together to increase the pressure and velocity of the air, ensuring optimal performance and efficiency of the engine.

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  • 39. 

    What happens to the energy that is absorbed by the turbine wheel?

    • 50 percent is used for accessories

    • 60 percent is used for accessories

    • It is returned to the compressor

    • It operates the anti-ice system

    Correct Answer
    A. It is returned to the compressor
    Explanation
    When the energy is absorbed by the turbine wheel, it is returned to the compressor. This is because the turbine wheel is connected to the compressor through a shaft. As the turbine wheel rotates, it transfers the energy back to the compressor, which then uses it to compress the incoming air. This process is essential for the functioning of the turbine engine, as it helps maintain a continuous flow of air and fuel for combustion.

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  • 40. 

    The parts on a can-annular combustion chamber section must be removed in a specific order because of the

    • Fuel nozzle

    • Transition liner

    • Combustion chamber outer case

    • Combustion chamber crossover tubes

    Correct Answer
    A. Combustion chamber crossover tubes
    Explanation
    The parts on a can-annular combustion chamber section must be removed in a specific order because of the combustion chamber crossover tubes. These tubes connect the different combustion chambers in the can-annular design, allowing for the flow of gases and combustion products. Removing the crossover tubes before other components ensures that the flow of gases is properly managed and that the combustion chamber can be disassembled without causing damage or disruption to the system.

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  • 41. 

    Which type of duct would decrease the velocity and increase the pressure of a gas as it passes through?

    • Elbow

    • Straight

    • Divergent

    • Convergent

    Correct Answer
    A. Divergent
    Explanation
    A divergent duct would decrease the velocity and increase the pressure of a gas as it passes through. In a divergent duct, the cross-sectional area gradually increases along the flow direction. This causes the gas to slow down and the pressure to increase. As the gas flows through the larger area, it experiences a decrease in velocity due to the conservation of mass principle. This decrease in velocity leads to an increase in pressure, according to Bernoulli's principle. Therefore, a divergent duct is the correct answer for this question.

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  • 42. 

    Foot-pounds and inch-pounds are units of measure for

    • Work

    • Power

    • Inertia

    • Friction

    Correct Answer
    A. Work
    Explanation
    Foot-pounds and inch-pounds are units of measure commonly used to quantify work. Work is defined as the amount of energy transferred by a force over a distance. The unit "pound" refers to a unit of force, and when multiplied by a unit of distance (foot or inch), it gives the unit of work. Therefore, foot-pounds and inch-pounds are used to measure the amount of work done in a system.

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  • 43. 

    The product of thermal efficiency and propulsive efficiency is

    • Mechanical efficiency

    • Overall efficiency

    • Power efficiency

    • Thrust efficiency

    Correct Answer
    A. Overall efficiency
    Explanation
    The product of thermal efficiency and propulsive efficiency is referred to as overall efficiency. This is because thermal efficiency measures the ratio of useful work output to the heat input, while propulsive efficiency measures the ratio of useful work output to the power input. Multiplying these two efficiencies together gives the overall efficiency, which represents the overall effectiveness of a system in converting energy inputs into useful work outputs.

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  • 44. 

    What is the required velocity for air and gases flowing through a jet engine?

    • Low velocity at all times

    • Less velocity exiting than entering

    • Equal velocity entering and exiting

    • Greater velocity exiting than entering

    Correct Answer
    A. Greater velocity exiting than entering
    Explanation
    The correct answer is "Greater velocity exiting than entering." In a jet engine, air and gases are compressed and heated before being expelled at a high velocity through the exhaust nozzle. This high velocity is necessary to generate thrust and propel the aircraft forward. The exit velocity is greater than the entering velocity to create a net force in the opposite direction, according to Newton's third law of motion.

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  • 45. 

    The purpose of the exhaust duct is to

    • Swirl exhaust gas-flow

    • Equalize exhaust gas-flow

    • Straighten exhaust gas flow

    • Modulate exhaust gas flow

    Correct Answer
    A. Straighten exhaust gas flow
    Explanation
    The purpose of the exhaust duct is to straighten the exhaust gas flow. This means that the duct is designed in a way that reduces turbulence and ensures a smooth and efficient flow of exhaust gases out of the system. By straightening the flow, the exhaust gases can exit the system more easily, improving overall performance and reducing any potential backpressure.

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  • 46. 

    Which type of defect appears on bearings as a result of small particles of foreign material becoming lodged between the rollers?

    • Pits

    • Bands

    • Grooves

    • Brinelling

    Correct Answer
    A. Grooves
    Explanation
    When small particles of foreign material become lodged between the rollers of bearings, it can cause grooves to appear on the surface. These grooves are a type of defect that can impair the smooth operation of the bearing. They can lead to increased friction, wear, and potential failure of the bearing over time. Therefore, the correct answer is "Grooves".

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  • 47. 

    On F100-PW-220 engine, the augmenter spray rings are pressure sensitive and can adjust their fuel nozzle openings in response to

    • Fuel temperature

    • Air temperature

    • Fuel pressure

    • Air velocity

    Correct Answer
    A. Fuel pressure
    Explanation
    The augmenter spray rings on the F100-PW-220 engine are designed to be pressure sensitive, meaning they can adjust their fuel nozzle openings based on changes in fuel pressure. This allows for precise control of the fuel flow and combustion process, ensuring optimal performance and efficiency of the engine. By responding to variations in fuel pressure, the augmenter spray rings can effectively regulate the amount of fuel being injected into the engine, resulting in improved fuel economy and power output.

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  • 48. 

    Which bearing is located in the low-pressure turbine (LPT) module of the F119-PW-100 engine?

    • No.2 bearing

    • No.3 bearing

    • No.4 bearing

    • No.5 bearing

    Correct Answer
    A. No.5 bearing
    Explanation
    The correct answer is No.5 bearing. The No.5 bearing is located in the low-pressure turbine (LPT) module of the F119-PW-100 engine.

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  • 49. 

    The air temperature of a jet engine gradually rises across the compressor to the diffuser outlet as a result of

    • Compression

    • Fuel expansion

    • Turbine discharge

    • Ambient temperature increase

    Correct Answer
    A. Compression
    Explanation
    The air temperature of a jet engine gradually rises across the compressor to the diffuser outlet as a result of compression. As the air passes through the compressor, it is compressed, which leads to an increase in temperature. This is because the compression process causes the air molecules to collide more frequently and with greater force, resulting in an increase in their kinetic energy and therefore temperature. Therefore, compression is the main factor responsible for the gradual temperature rise in the jet engine.

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  • Jul 15, 2024
    Quiz Edited by
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  • Aug 10, 2015
    Quiz Created by
    CDCmaster
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