CDC Volume 2 Edit Code 2
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Questions and Answers
- 1.
An aircraft taxiing at a steady speed can be used to demonstrate
- A.
Bernoulli’s principle.
- B.
Newton’s first law of motion.
- C.
Newton’s second law of motion.
- D.
Newton’s third law of motion.
Correct Answer
B. Newton’s first law of motion.Explanation
An aircraft taxiing at a steady speed demonstrates Newton's first law of motion, also known as the law of inertia. According to this law, an object at rest or in motion will continue to stay at rest or in motion with the same speed and direction unless acted upon by an external force. In this case, the aircraft is in motion and continues to move at a steady speed because there are no external forces acting on it to change its state of motion.Rate this question:
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- 2.
Which law may you sum up with two words: action and reaction?
- A.
Bernoulli’s principle.
- B.
Newton’s first law of motion.
- C.
Newton’s second law of motion.
- D.
Newton’s third law of motion.
Correct Answer
D. Newton’s third law of motion.Explanation
Newton's third law of motion states that for every action, there is an equal and opposite reaction. This means that when an object exerts a force on another object, the second object exerts a force of equal magnitude but in the opposite direction on the first object. This law explains the concept of action and reaction, which is summarized in the two words "action" and "reaction". Bernoulli's principle, Newton's first law of motion, and Newton's second law of motion do not specifically address the concept of action and reaction.Rate this question:
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- 3.
Which type of duct would decrease the velocity and increase the pressure of a gas as it passes through?
- A.
Elbow.
- B.
Straight.
- C.
Divergent.
- D.
Convergent.
Correct Answer
C. Divergent.Explanation
A divergent duct is designed to gradually increase in size, causing the gas to expand and slow down as it passes through. This decrease in velocity leads to an increase in pressure. Therefore, a divergent duct would decrease the velocity and increase the pressure of a gas as it passes through.Rate this question:
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- 4.
The ability to do work is the definition of
- A.
Energy.
- B.
Inertia.
- C.
Friction.
- D.
Velocity.
Correct Answer
A. Energy.Explanation
Energy is defined as the ability to do work. Work is the transfer of energy from one object to another, or the transformation of energy from one form to another. In this context, inertia refers to an object's resistance to changes in its motion, friction refers to the resistance encountered when two surfaces rub against each other, and velocity refers to the speed and direction of an object's motion. None of these definitions align with the given question. Therefore, the correct answer is energy.Rate this question:
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- 5.
What does fuel for an engine represent?
- A.
Thrust produced.
- B.
Efficiency ratio.
- C.
Potential energy.
- D.
Available horsepower.
Correct Answer
C. Potential energy.Explanation
Fuel for an engine represents potential energy. When fuel is burned, it releases energy in the form of heat, which is then converted into mechanical energy to power the engine. This potential energy is stored in the fuel and is harnessed to generate the necessary power for the engine to function.Rate this question:
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- 6.
The temperature of compressed air in a jet engine must be raised to
- A.
Increase energy.
- B.
Decrease energy.
- C.
Increase volume.
- D.
Decrease volume.
Correct Answer
A. Increase energy.Explanation
In a jet engine, the temperature of compressed air needs to be raised in order to increase the energy. This is because increasing the temperature of the air increases its kinetic energy, which in turn increases the thrust produced by the engine. By raising the temperature, the air molecules move faster and collide with greater force, resulting in a higher energy output.Rate this question:
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- 7.
Which section of a jet engine introduces and burns fuel?
- A.
Turbine.
- B.
Diffuser.
- C.
Compressor.
- D.
Combustion.
Correct Answer
D. Combustion.Explanation
The section of a jet engine that introduces and burns fuel is the combustion section. This is where the fuel is mixed with air and ignited, creating a high-temperature and high-pressure environment. The combustion process produces hot gases that expand and create the necessary thrust to propel the aircraft forward. The other options, turbine, diffuser, and compressor, are all components of a jet engine but do not specifically introduce and burn fuel.Rate this question:
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- 8.
Which method of producing thrust does a turboprop engine use?
- A.
Using only the energy expended through the exhaust nozzle to propel the aircraft forward.
- B.
Using the same working fluid for propulsive force as that used within the engine.
- C.
Accelerating a large mass of air through a small velocity change.
- D.
Moving a small quantity of air through a large velocity change.
Correct Answer
C. Accelerating a large mass of air through a small velocity change.Explanation
A turboprop engine uses the method of accelerating a large mass of air through a small velocity change to produce thrust. This is achieved by using a turbine to drive a propeller, which accelerates a large amount of air backwards. According to Newton's third law of motion, the reaction to this backward acceleration is a forward thrust on the aircraft. This method is efficient for low-speed aircraft and allows for a combination of jet propulsion and propeller propulsion.Rate this question:
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- 9.
Which type of horsepower is delivered to the propeller for useful work?
- A.
Brake.
- B.
Indicated.
- C.
Frictional.
- D.
Equivalent shaft.
Correct Answer
A. Brake.Explanation
The correct answer is Brake. Brake horsepower refers to the power delivered to the propeller for useful work. It represents the actual power output of the engine, taking into account any losses due to friction or other factors. Indicated horsepower, on the other hand, is the power calculated based on the pressure inside the cylinders, while frictional horsepower represents the power lost due to friction in the engine. Equivalent shaft horsepower is a measure of the power output of a turbine engine.Rate this question:
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- 10.
Which type of horsepower determines the performance of the engine-propeller combination?
- A.
Brake.
- B.
Indicated.
- C.
Frictional.
- D.
Equivalent shaft.
Correct Answer
D. Equivalent shaft.Explanation
The equivalent shaft horsepower determines the performance of the engine-propeller combination. This type of horsepower takes into account the power losses that occur between the engine and the propeller, such as mechanical losses and losses due to the propeller efficiency. It provides a more accurate measure of the actual power available for propulsion and is therefore a better indicator of the engine-propeller combination's performance.Rate this question:
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- 11.
The two fluids combined to make up common jet fuel are
- A.
Gasoline and oil
- B.
Kerosene and oil.
- C.
Gasoline and water.
- D.
Kerosene and gasoline.
Correct Answer
D. Kerosene and gasoline.Explanation
The correct answer is kerosene and gasoline. Jet fuel is a type of aviation fuel that is specifically designed for use in jet engines. It is a mixture of kerosene and gasoline, which are both hydrocarbon-based fuels. Kerosene provides the necessary energy and stability for the engine, while gasoline helps to improve the fuel's performance and ignition characteristics. This combination of kerosene and gasoline ensures that the jet fuel has the right balance of properties to meet the requirements of jet engines.Rate this question:
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- 12.
Which is not a method of heat transfer?
- A.
Radiation.
- B.
Convection.
- C.
Penetration.
- D.
Conduction.
Correct Answer
C. Penetration.Explanation
Penetration is not a method of heat transfer. Heat transfer occurs through conduction, convection, and radiation. Conduction is the transfer of heat through direct contact between two objects or substances. Convection is the transfer of heat through the movement of fluids or gases. Radiation is the transfer of heat through electromagnetic waves. Penetration, on the other hand, does not involve the transfer of heat but refers to the ability of a substance or object to pass through another material.Rate this question:
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- 13.
The air temperature of a jet engine gradually rises across the compressor to the diffuser outlet as a result of
- A.
Compression.
- B.
Fuel expansion.
- C.
Turbine discharge.
- D.
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. This is because the compressor compresses the incoming air, increasing its pressure and density. As the air is compressed, its molecules become closer together, leading to an increase in temperature. Therefore, compression is the process that causes the air temperature to rise in the jet engine.Rate this question:
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- 14.
Where is the highest point of temperature reached in an engine?
- A.
Tailpipe.
- B.
Exhaust cone.
- C.
Turbine section.
- D.
Combustion section.
Correct Answer
D. Combustion section.Explanation
The highest point of temperature is reached in the combustion section of an engine. This is where the fuel is ignited and burned, resulting in a rapid increase in temperature. The combustion section is designed to withstand these high temperatures and convert the energy released from the combustion process into mechanical work.Rate this question:
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- 15.
Which engine component meters fuel for combustion?
- A.
P&D valve.
- B.
Fuel pump.
- C.
Fuel control.
- D.
Fuel nozzles.
Correct Answer
C. Fuel control.Explanation
The fuel control is responsible for metering fuel for combustion in the engine. It regulates the flow of fuel to ensure the correct amount is delivered to the combustion chamber. This component plays a crucial role in maintaining the proper fuel-to-air ratio for efficient combustion and optimal engine performance.Rate this question:
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- 16.
What happens to the energy that is absorbed by the turbine wheel?
- A.
50 percent is used for accessories.
- B.
60 percent is used for accessories.
- C.
The energy operates the anti-ice system.
- D.
The energy is returned to the compressor.
Correct Answer
D. The energy is returned to the compressor.Explanation
When the energy is absorbed by the turbine wheel, it is then returned to the compressor. This means that the energy is recycled and reused within the system, rather than being lost or wasted. This process allows for more efficient operation of the turbine and helps to maximize energy utilization.Rate this question:
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- 17.
On an average, what percent of all the energy produced by the fuel is required to maintain the engine operating cycle?
- A.
50
- B.
60
- C.
70
- D.
80
Correct Answer
B. 60Explanation
The correct answer is 60. This means that, on average, 60% of all the energy produced by the fuel is required to maintain the engine operating cycle. This suggests that a significant portion of the energy generated by the fuel is used to keep the engine running efficiently.Rate this question:
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- 18.
What directs the gases onto the first-stage turbine wheel blades in a jet engine?
- A.
Turbine wheel blades.
- B.
Combustion chamber.
- C.
Turbine stator.
- D.
Flameholder.
Correct Answer
C. Turbine stator.Explanation
The turbine stator directs the gases onto the first-stage turbine wheel blades in a jet engine. The stator is a stationary component in the engine that consists of a series of vanes or blades. It is positioned between the combustion chamber and the turbine wheel. As the gases flow through the stator, the vanes or blades redirect and guide the gases onto the turbine wheel blades, which in turn convert the gas energy into mechanical energy to drive the engine.Rate this question:
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- 19.
A jet engine derives its name from its design in that it uses
- A.
Turbo-superchargers within the engine.
- B.
A turbine-type compressor to maintain power.
- C.
Nozzles which are called jet within the engine.
- D.
A gas-driven turbine wheel to drive its compressor.
Correct Answer
D. A gas-driven turbine wheel to drive its compressor.Explanation
A jet engine uses a gas-driven turbine wheel to drive its compressor. This means that the turbine wheel is powered by the force of the gas flowing through the engine, which in turn drives the compressor. This design allows the engine to generate the necessary power and airflow for propulsion. The other options mentioned, such as turbo-superchargers and nozzles, are not directly related to the design of a jet engine.Rate this question:
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- 20.
Vane-type fuel pumps used in jet engines are similar to
- A.
Sliding-vane air compressors.
- B.
Piston pump air compressors.
- C.
Roots air compressors.
- D.
Turbo-superchargers.
Correct Answer
A. Sliding-vane air compressors.Explanation
Vane-type fuel pumps used in jet engines are similar to sliding-vane air compressors. Both types of pumps use a set of vanes that slide in and out of slots in a rotor to create a pumping action. This design allows for efficient and reliable fuel or air delivery. The other options, piston pump air compressors, roots air compressors, and turbo-superchargers, have different mechanisms and are not directly comparable to vane-type fuel pumps.Rate this question:
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- 21.
Which condition reduces the efficiency of a centrifugal compressor?
- A.
Resultant velocity.
- B.
Tangential velocity.
- C.
Pressure pulsations
- D.
Air mass leaving the impeller at great velocities.
Correct Answer
C. Pressure pulsationsExplanation
Pressure pulsations can reduce the efficiency of a centrifugal compressor. These pulsations occur when there are fluctuations in the pressure within the compressor, causing uneven flow and turbulence. This can lead to energy losses and decreased efficiency.Rate this question:
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- 22.
Stationary vanes positioned between rotor discs in a compressor are used to
- A.
Direct air and increase pressure
- B.
Direct hot gases rearward.
- C.
Increase backup pressure.
- D.
Prolong compressor life.
Correct Answer
A. Direct air and increase pressureExplanation
The stationary vanes positioned between rotor discs in a compressor are used to direct air and increase pressure. These vanes help to guide the airflow and redirect it in the desired direction, increasing the pressure as the air passes through the compressor. By controlling the airflow and increasing the pressure, these vanes play a crucial role in the efficient operation of the compressor.Rate this question:
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- 23.
The jet engine compressor that is cheaper to manufacture is the
- A.
Axial-flow type, because of its size.
- B.
Centrifugal type, because of its size.
- C.
Axial-flow type, because of its fewer parts.
- D.
Centrifugal type, because of its fewer parts.
Correct Answer
D. Centrifugal type, because of its fewer parts.Explanation
The centrifugal type of jet engine compressor is cheaper to manufacture because it has fewer parts compared to the axial-flow type. This means that there are fewer components to design, manufacture, and assemble, resulting in lower production costs. Additionally, the simpler design of the centrifugal compressor may also require less maintenance and have a longer lifespan, further reducing overall costs.Rate this question:
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- 24.
The percentage of combustion efficiency of a gas turbine is usually between
- A.
60 and 70.
- B.
65 and 75.
- C.
75 and 95
- D.
95 and 100.
Correct Answer
D. 95 and 100.Explanation
The percentage of combustion efficiency of a gas turbine refers to the amount of fuel that is effectively converted into useful energy. A higher percentage indicates a more efficient combustion process. The range of 95 and 100 suggests that the gas turbine is highly efficient, with minimal fuel wastage and maximum energy conversion.Rate this question:
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- 25.
What is the most probable cause of a flameout of a jet engine flying at 40,000 feet with a constant engine revolutions per minute (rpm) of 50 percent?
- A.
The rpm is too low.
- B.
A decrease in barometric pressure.
- C.
The failure of the breather pressurizing valve.
- D.
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 too low, it can lead to insufficient fuel flow and inadequate combustion, resulting in a flameout. This can happen especially at higher altitudes where the air is thinner and the engine requires a higher rpm to maintain proper combustion.Rate this question:
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- 26.
Carbon monoxide gas is poisonous and odorless, and has
- A.
A reddish color.
- B.
A greenish color
- C.
A yellowish color.
- D.
No color.
Correct Answer
D. No color.Explanation
Carbon monoxide gas is poisonous and odorless, meaning it cannot be detected by our senses. It does not have any color, making it even more dangerous as it cannot be seen. This lack of color allows carbon monoxide to go unnoticed, increasing the risk of poisoning. It is crucial to have carbon monoxide detectors in homes and other spaces to ensure early detection and prevention of this deadly gas.Rate this question:
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- 27.
What is the most chemically correct ratio for burning fuel in a combustion chamber?
- A.
10:1.
- B.
10:4.
- C.
15:1.
- D.
15:4.
Correct Answer
C. 15:1.Explanation
The most chemically correct ratio for burning fuel in a combustion chamber is 15:1. This ratio ensures that there is enough fuel to react with the oxygen in the air, resulting in complete combustion. A ratio of 15 parts fuel to 1 part air provides the optimal conditions for efficient and clean combustion, minimizing the production of harmful byproducts such as carbon monoxide and unburned hydrocarbons.Rate this question:
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- 28.
The inner and outer surfaces of an annular-type combustion chamber are formed by
- A.
Interlocking stainless-steel bands.
- B.
The inner and outer diffuser case.
- C.
A forged steel casing.
- D.
Solid sheet metal.
Correct Answer
A. Interlocking stainless-steel bands.Explanation
The correct answer is interlocking stainless-steel bands. This is because an annular-type combustion chamber is typically made up of two concentric rings or bands that interlock with each other to form the inner and outer surfaces of the chamber. These bands are usually made of stainless steel, which is a durable and heat-resistant material suitable for withstanding the high temperatures and pressures of the combustion process. This design allows for efficient combustion and helps to contain the combustion gases within the chamber.Rate this question:
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- 29.
Fuel that accumulates after a failed start is
- A.
Returned to the fuel control by tubes.
- B.
Drained overboard by a drain system.
- C.
Burned on the next start attempt.
- D.
Allowed to evaporate.
Correct Answer
B. Drained overboard by a drain system.Explanation
After a failed start, the fuel that accumulates is drained overboard by a drain system. This is done to prevent the fuel from causing any damage or contamination to the fuel control system. Draining the fuel overboard ensures that it is safely removed from the system and does not interfere with the next start attempt.Rate this question:
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- 30.
The parts on a can-annular combustion section must be removed in a specific order because of the
- A.
Fuel nozzle.
- B.
Transition liner.
- C.
Combustion chamber outer case.
- D.
Combustion chamber crossover tubes.
Correct Answer
D. Combustion chamber crossover tubes.Explanation
The combustion chamber crossover tubes must be removed in a specific order because they connect the combustion chambers in a can-annular combustion section. These tubes allow for the flow of hot gases between the combustion chambers, ensuring proper combustion and efficient operation of the engine. Removing the crossover tubes in a specific order prevents any disruption to the flow of gases and maintains the integrity of the combustion section.Rate this question:
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- 31.
What is the most common type of fuel nozzle system?
- A.
Pressure-atomizing.
- B.
Fuel-blasting.
- C.
Fuel ejector.
- D.
Fuel tube.
Correct Answer
A. Pressure-atomizing.Explanation
The most common type of fuel nozzle system is pressure-atomizing. This system uses high-pressure air or steam to atomize the fuel into small particles, allowing for efficient combustion. It is widely used in various industries, including aviation, automotive, and power generation. This type of nozzle system ensures proper fuel distribution and combustion control, resulting in improved fuel efficiency and reduced emissions.Rate this question:
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- 32.
What type of flame speed are swirl-type fuel nozzles normally used to provide?
- A.
Low.
- B.
High.
- C.
Medium.
- D.
Medium-high.
Correct Answer
B. High.Explanation
Swirl-type fuel nozzles are designed to create a swirling motion in the fuel-air mixture, which enhances the combustion process. This swirling motion increases the flame speed, allowing for a more efficient and complete combustion. Therefore, swirl-type fuel nozzles are typically used to provide a high flame speed.Rate this question:
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- 33.
What is placed in front of the rotating blades in a multiple-stage turbine engine?
- A.
Rotating vanes.
- B.
Inlet guide vanes.
- C.
Turbine rotating nozzles.
- D.
Turbine nozzle vane assembly.
Correct Answer
D. Turbine nozzle vane assembly.Explanation
The correct answer is turbine nozzle vane assembly. In a multiple-stage turbine engine, the turbine nozzle vane assembly is placed in front of the rotating blades. This assembly consists of a series of vanes that direct the flow of hot gases onto the turbine blades, allowing for efficient energy transfer and power generation.Rate this question:
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- 34.
The “fir tree” method of attaching turbine blades (buckets) to the turbine rotor disc is preferred because
- A.
Of the temperature differential between the turbine rotor disc and the blades.
- B.
It aids in preventing horizontal movement of the blades.
- C.
There is more blade tip shake during engine operation.
- D.
It aids in preventing axial movement of the bucket.
Correct Answer
A. Of the temperature differential between the turbine rotor disc and the blades.Explanation
The "fir tree" method of attaching turbine blades to the rotor disc is preferred because of the temperature differential between the disc and the blades. This method allows for better thermal expansion and contraction of the blades, ensuring a secure and stable attachment. The temperature difference can cause the blades and the disc to expand and contract at different rates, and the fir tree design accommodates this movement effectively. This helps to prevent any potential damage or failure of the blades due to thermal stresses, making it a suitable choice for turbine blade attachment.Rate this question:
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- 35.
Which method of attaching the turbine blades (buckets) to the turbine rotor disc is used most frequently ?
- A.
Turbine blades fitted solidly into the rim of the rotor disc.
- B.
Rivet placed in a hole through the base of the turbine blade.
- C.
Close-fitting shroud ring around the outer perimeter of the disc.
- D.
Series of grooves or notches broached in the rim of the turbine rotor disc.
Correct Answer
D. Series of grooves or notches broached in the rim of the turbine rotor disc.Explanation
The most frequently used method of attaching the turbine blades (buckets) to the turbine rotor disc is by using a series of grooves or notches broached in the rim of the disc. This method ensures a secure and reliable connection between the blades and the disc, allowing for efficient power transfer and minimizing the risk of blade detachment during operation. The grooves or notches provide a mechanical interlock that prevents the blades from rotating or sliding out of position, even under high rotational forces and vibrations. This method is widely adopted in turbine design due to its effectiveness and durability.Rate this question:
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- 36.
The exhaust duct connects the turbine outlet and the
- A.
Fan duct
- B.
Jet nozzle.
- C.
Fuel nozzle.
- D.
Bifurcated duct.
Correct Answer
B. Jet nozzle.Explanation
The exhaust duct connects the turbine outlet and the jet nozzle. The jet nozzle is responsible for accelerating the exhaust gases and creating thrust in a jet engine. It is the final part of the engine where the high-speed exhaust gases are expelled, creating the propulsive force. The other options mentioned, such as the fan duct, fuel nozzle, and bifurcated duct, are not directly connected to the turbine outlet and do not play a role in accelerating the exhaust gases.Rate this question:
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- 37.
The purpose of the exhaust duct is to
- A.
Swirl exhaust gas-flow.
- B.
Equalize exhaust gas-flow.
- C.
Straighten exhaust gas-flow.
- D.
Modulate exhaust gas-flow.
Correct Answer
C. 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 to remove any turbulence or irregularities in the flow of the exhaust gases, ensuring that they exit the system in a smooth and streamlined manner. Straightening the exhaust gas-flow helps to optimize the performance of the system, reduce energy losses, and improve overall efficiency.Rate this question:
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- 38.
Which component in the augmentor creates local turbulence and reduces gas velocity?
- A.
Spraybars.
- B.
Flameholder.
- C.
Screech liner.
- D.
Fuel manifold.
Correct Answer
B. Flameholder.Explanation
The flameholder is the component in the augmentor that creates local turbulence and reduces gas velocity. It is designed to stabilize the flame and ensure its continuous combustion. By creating turbulence, the flameholder helps to mix fuel and air more effectively, improving combustion efficiency. Additionally, the reduced gas velocity allows for better control of the flame and prevents flame blowout. Spraybars, screech liner, and fuel manifold do not directly create turbulence or reduce gas velocity in the augmentor.Rate this question:
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- 39.
How many different types of loads can be imposed on a jet engine bearing?
- A.
Two.
- B.
Three.
- C.
Four.
- D.
Five.
Correct Answer
B. Three.Explanation
The correct answer is three because a jet engine bearing can experience three different types of loads: radial load, axial load, and moment load. Radial load is the force acting perpendicular to the axis of the bearing, axial load is the force acting parallel to the axis of the bearing, and moment load is the force acting at a distance from the center of the bearing, causing a twisting effect.Rate this question:
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- 40.
Before inspecting new jet engine bearings, you should
- A.
Separate the halves.
- B.
Perform a spin check.
- C.
Apply a preservative coating.
- D.
Remove the preservative coating.
Correct Answer
D. Remove the preservative coating.Explanation
Before inspecting new jet engine bearings, it is necessary to remove the preservative coating. The preservative coating is applied to protect the bearings during storage and transportation. However, this coating can interfere with the inspection process and potentially hide any defects or damage that may be present. Therefore, it is important to remove the preservative coating before inspecting the bearings to ensure a thorough and accurate examination.Rate this question:
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- 41.
The most commonly used bearing removal tools include
- A.
Drift pipes and hammers.
- B.
Bearing pullers and hammers.
- C.
Drift pipes and arbor presses.
- D.
Arbor presses and bearing pullers.
Correct Answer
D. Arbor presses and bearing pullers.Explanation
Arbor presses and bearing pullers are the most commonly used tools for removing bearings. Arbor presses provide controlled pressure to push the bearing out of its housing, while bearing pullers use hooks or claws to grip and pull the bearing out. These tools are effective in safely and efficiently removing bearings without causing damage to the surrounding components. Drift pipes and hammers may be used in certain situations, but they are not as commonly used as arbor presses and bearing pullers.Rate this question:
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- 42.
Which type of defect appears on bearings as a result of bearing parts striking together?
- A.
Nicks.
- B.
Galling.
- C.
Grooves.
- D.
Scratches.
Correct Answer
A. Nicks.Explanation
Nicks are a type of defect that appear on bearings as a result of bearing parts striking together. When the parts strike, small chips or dents can be formed on the surface of the bearing, creating nicks. These nicks can cause problems such as increased friction, reduced performance, and potential failure of the bearing over time. Therefore, nicks are a common type of defect that can occur on bearings due to the striking of bearing parts.Rate this question:
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- 43.
Which type of defect appears on bearings as a result of small particles of foreign material becoming lodged between the rollers?
- A.
Pits.
- B.
Bands.
- C.
Grooves.
- D.
Brinelling.
Correct Answer
C. Grooves.Explanation
When small particles of foreign material become lodged between the rollers of bearings, it can lead to the formation of grooves on the surface. These grooves can cause uneven wear and damage to the bearing, affecting its performance and lifespan. Pits, bands, and brinelling are other types of defects that can occur in bearings, but in this case, the correct answer is grooves.Rate this question:
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- 44.
Which type of bearing defect results from inadequate lubrication?
- A.
Bands.
- B.
Galling.
- C.
Grooves.
- D.
Brinelling.
Correct Answer
B. Galling.Explanation
Galling is a type of bearing defect that occurs due to inadequate lubrication. When there is insufficient lubrication between the bearing surfaces, friction and heat increase, causing the surfaces to seize and stick together. This leads to metal transfer and the formation of rough spots or protrusions on the surfaces, known as galling. Galling can cause damage to the bearing and result in reduced performance and premature failure.Rate this question:
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- 45.
Before you install separable bearings, you must ensure the
- A.
Rollers are serviceable.
- B.
Bearings are a matched set.
- C.
Rollers are properly positioned.
- D.
Parts are positioned and serviceable.
Correct Answer
B. Bearings are a matched set.Explanation
The correct answer is "bearings are a matched set." This means that before installing separable bearings, it is important to ensure that the bearings being used are a matched set. This means that they are designed to work together and have been manufactured to the same specifications. Using mismatched bearings can lead to improper functioning and potential damage to the equipment.Rate this question:
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- 46.
Of the following, the recommended method of expanding a bearing race before installation is to use a
- A.
Hot-oil bath.
- B.
Coal furnace.
- C.
Hydraulic-oil bath.
- D.
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 is because heating the bearing race in a hot-oil bath causes it to expand, making it easier to fit onto the shaft or housing. The hot oil helps to evenly distribute heat and prevent damage to the bearing race. Using a coal furnace or an oscillating heater may result in uneven heating and potential damage to the bearing race. A hydraulic-oil bath is not commonly used for expanding bearing races.Rate this question:
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- 47.
Which component reduces the engine rotor speed to the revolutions per minute (rpm) required for accessories?
- A.
Step motors.
- B.
Reduction motor.
- C.
Reduction geartrain.
- D.
Gear case drive assembly.
Correct Answer
C. Reduction geartrain.Explanation
The reduction geartrain is responsible for reducing the engine rotor speed to the required revolutions per minute (rpm) for accessories. This component is designed to decrease the speed and increase the torque of the engine, allowing it to efficiently power the various accessories in a vehicle or machine. The reduction geartrain consists of a series of gears with different sizes, which work together to slow down the rotation speed and transfer power to the accessories at the desired rpm.Rate this question:
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- 48.
The reduction gearbox on an F100–PW–220 engine reduces speed between the main fuel gear pump and the engine-driven main gearbox by
- A.
45 percent.
- B.
33 percent.
- C.
46 percent.
- D.
52 percent.
Correct Answer
D. 52 percent.Explanation
The reduction gearbox on an F100-PW-220 engine reduces the speed between the main fuel gear pump and the engine-driven main gearbox by 52 percent.Rate this question:
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- 49.
To cause an accessory in a jet engine to operate at its most optimum speed, design engineers must
- A.
Change the gear ratio.
- B.
Change the governor setting.
- C.
Install an additional set of drive gears.
- D.
Adjust the operating speed of the engine.
Correct Answer
A. Change the gear ratio.Explanation
To operate an accessory in a jet engine at its most optimum speed, design engineers need to change the gear ratio. The gear ratio determines the relationship between the speed of the engine and the speed of the accessory. By adjusting the gear ratio, engineers can ensure that the accessory operates at the desired speed, maximizing its efficiency and performance. This can be achieved by either increasing or decreasing the gear ratio, depending on the specific requirements of the accessory.Rate this question:
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- 50.
On a F108 engine, which component serves as the mechanical coupling between the compressor rotor and the transfer gearbox (TGB)?
- A.
Power take-off (PTO) drive shaft.
- B.
Accessory gearbox (AGB).
- C.
Inlet gearbox (IGB).
- D.
Radial drive shaft.
Correct Answer
C. Inlet gearbox (IGB).Explanation
The correct answer is Inlet gearbox (IGB). The inlet gearbox (IGB) serves as the mechanical coupling between the compressor rotor and the transfer gearbox (TGB) on a F108 engine. It is responsible for transferring the power generated by the compressor rotor to the TGB, which then transfers the power to other engine components.Rate this question:
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Aug 21, 2023Quiz Edited by
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Sep 30, 2012Quiz Created by
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