Volume 3 - 2014 CDC 2a651s Jet Aircraft

The C-D supersonic inlet uses Bernoulli's law to slow down the airflow. Bernoulli's law states that as the speed of a fluid increases, its pressure decreases. In the case of the supersonic inlet, the airflow is slowed down by increasing its pressure. This is achieved by using a converging-diverging shape in the inlet, which causes the airflow to accelerate initially and then decelerate, resulting in a decrease in velocity and an increase in pressure.

Once the cooling airflow has done its job of cooling the turbine section, it is directed into the gas stream to exit the engine. This is because the cooling airflow has absorbed heat from the turbine section and needs to be expelled from the engine to maintain proper operating temperatures. Redirecting the airflow into the gas stream allows it to be safely released from the engine without affecting the overall performance.

The correct answer is IGVs and VSVs. The F110-GE-129 engine controls airflow through the engine using both the Inlet Guide Vanes (IGVs) and Variable Stator Vanes (VSVs). The IGVs are located at the front of the engine and help to control the airflow entering the engine. The VSVs are located in the compressor section of the engine and help to control the airflow through the compressor. By adjusting the position of both the IGVs and VSVs, the engine can effectively control the airflow and optimize engine performance.

The question asks for a type of oil pump that is not classified by structure. The options provided are Gear, Gerotor, Rotogear, and Sliding vane. The correct answer is Rotogear because it is not a recognized type of oil pump. Gear, Gerotor, and Sliding vane are all valid types of oil pumps that are classified by their specific structures.

The project monitor is responsible for ensuring that the OAP (Operational Availability Plan) operates properly. They oversee and monitor the progress of the project, ensuring that all aspects are functioning as intended. This includes coordinating with various team members, tracking the project's performance, and making any necessary adjustments to ensure its success. The project monitor plays a crucial role in ensuring the smooth operation of the OAP.

The correct answer is DEEC. The DEEC (Digital Electronic Engine Control) is the component that controls the augmentor fuel control on the F100-PW-220 engine. It is responsible for monitoring and regulating the fuel flow to the augmentor, which is a device used to increase the thrust of the engine during afterburner operation. The DEEC ensures that the correct amount of fuel is delivered to the augmentor, optimizing engine performance and efficiency.

The correct answer is the Filter assembly bypass valve. During cold weather starts, the oil filter can become clogged with cold, thick oil. The filter assembly bypass valve allows the oil to bypass the filter and flow directly to the engine, ensuring that the engine receives the necessary lubrication even if the filter is not functioning optimally. This helps to protect the engine from damage during cold starts.

The hydraulic motor is the item that initially rotates the JFS (Jet Fuel Starter) in this scenario. This means that the hydraulic motor is responsible for providing the initial rotational force to start the JFS. The other options, such as the ESS PTO, electric motor mounted on the aircraft, and engine PTO, are not mentioned as being involved in the initial rotation of the JFS.

The Engine Monitoring System Computer in the F110 monitoring system performs diagnostics and fault isolation to line replaceable units. This component is responsible for monitoring the engine's performance, detecting any faults or abnormalities, and isolating the faulty components for replacement. It plays a crucial role in ensuring the proper functioning and maintenance of the engine.

The fuel/oil cooler heats the augmentor fuel to provide better vaporization and combustion. This component helps to cool the oil and fuel, ensuring that the fuel is at the optimal temperature for efficient combustion. By cooling the fuel, the fuel/oil cooler helps to prevent overheating and improve the overall performance of the engine.

Oil sampling intervals should not vary by more than 10 percent. This means that the time between oil sampling should not deviate by more than 10 percent from the recommended interval. This is important because regular oil sampling helps monitor the condition of the oil and the equipment it is used in. By adhering to a consistent sampling interval, any changes in oil quality or equipment performance can be detected in a timely manner, allowing for necessary maintenance or repairs to be carried out. Varying the sampling intervals by more than 10 percent could lead to inaccurate assessments of oil and equipment condition, potentially causing damage or failure.

The correct answer is "bleeds off air after it has entered the engine." The bleed air system is designed to remove excess air from the engine after it has entered. This is done to prevent damage to the engine caused by excessive pressure or temperature. In contrast, the variable vane system is responsible for controlling the airflow into the engine, allowing for optimal performance. Therefore, the bleed air system and the variable vane system serve different functions in the overall operation of an engine.

The VSV (Variable Stator Vane) on an F110-GE-129 engine are fully closed (cambered) when the core engine speed is below 45 percent.

The correct answer is rear compressor variable vane actuators with fuel pressure. This means that the MFC (Main Fuel Control) provides fuel pressure to the rear compressor variable vane actuators in order to actuate them. This allows for the adjustment of the variable vanes in the rear compressor section of the F100-PW-220 engine, which helps optimize engine performance and efficiency.

Ice formation at aircraft engine inlets can disrupt the smooth flow of air into the engine, leading to a decrease in airflow and an increase in air pressure. This disruption can cause the compressor blades to stall, which is characterized by a sudden loss of engine power and a distinctive banging or popping sound. Therefore, a compressor stall is one of the first indications of ice formation at aircraft engine inlets.

The cooling air for turbine nozzle vanes comes from the last few stages of the compressor. This means that the air used for cooling is taken from the later stages of the compressor, rather than from all stages or just the middle or first few stages. This is important because the air from the last stages of the compressor is typically cooler, which helps to prevent overheating of the turbine nozzle vanes and maintain their efficiency.

The function of the flexible feedback cable on the F110-GE-129 engine variable vane system is to transmit a mechanical feedback signal to the main engine control. This feedback signal helps the main engine control in monitoring and adjusting the position of the variable vanes, ensuring optimal engine performance and efficiency.

During jet engine deceleration, a hydromechanical fuel control schedules fuel flow as a function of burner pressure. This means that the fuel flow is adjusted based on the pressure in the burner. This is important because the burner pressure directly affects the combustion process, and by controlling the fuel flow in relation to the burner pressure, the engine can maintain optimal performance and efficiency during deceleration. The other options, RPM, inlet temperature, and inlet pressure, are not directly related to the fuel flow adjustment during deceleration.

In a simple AC generator, the slip rings are connected to the rotating loop, which generates the alternating current. The brushes are in contact with the slip rings and serve as the connection point to transfer the current from the slip rings to the electrical device. Therefore, the brushes are responsible for taking the current from the slip rings to operate the electrical device.

The commutator is the part of a generator that acts as an automatic switching device, changing the alternating current produced by the generator into direct current. It consists of a set of contacts that are connected to the rotating armature of the generator. As the armature rotates, the contacts make and break contact with the brushes, effectively converting the alternating current to direct current. The slip rings and brushes are also important components of a generator, but they do not perform the function of converting AC to DC.

The correct answer is Torch igniter and pilot burner ring. These two types of augmentor (afterburner) ignition systems are commonly used in aircraft engines. The torch igniter is responsible for igniting the fuel-air mixture in the afterburner, while the pilot burner ring provides a continuous flame to sustain the combustion process. Both systems work together to ensure efficient and reliable ignition of the afterburner.

The F100 engine augmentor's primary nozzle actuator is driven by cables from the CENC.

A dry sump oil system stores the oil in a separate tank that is fitted to the side of the engine. This system is commonly used in high-performance or racing engines because it allows for better oil control and prevents oil starvation during high-speed or high-g turns. The oil is pumped from the tank to lubricate the engine components and then returned to the tank to be cooled and filtered before being recirculated. In contrast, a wet sump system stores the oil in a pan at the bottom of the engine, which is simpler but can lead to oil sloshing and starvation in extreme conditions.

In a hot tank oil system design, the oil cooler is placed in the pressure subsystem. This means that the oil cooler is located after the oil pump, where the oil is pressurized. The purpose of the oil cooler is to cool down the hot oil before it is circulated back into the engine. By placing the oil cooler in the pressure subsystem, the oil is cooled more effectively as it is exposed to higher pressure, allowing for better heat dissipation.

Most fighter aircraft engines incorporate a hot tank design for oil tanks to help with weight savings. A hot tank design allows for better heat dissipation, reducing the need for additional cooling systems. This helps to save weight and improve overall aircraft performance.

The correct answer is three because the question is asking about the number of sets of imbedded magnets in the rotor. Since the question does not specify the type of magnets or provide any additional information, we can assume that there are three sets of imbedded magnets in the rotor.

The turbine plenum on the JFS provides pads for mounting the fuel atomizer assembly.

The most important advantage of using a C-D nozzle system is that it increases the life expectancies of the engine and augmentor. This means that the engine and augmentor will last longer and have a longer operational lifespan. This is beneficial as it reduces the need for frequent repairs or replacements, leading to cost savings and improved reliability of the engine system.

The correct answer is afterburner fuel control. In the F100 engine augmentor, the divergent and convergent nozzle segments form a four-bar linkage arrangement that controls the afterburner fuel control. This means that the movement of the nozzle segments is directly linked to the control of the fuel flow in the afterburner, allowing for efficient and precise control of the engine's thrust output.

The number 1, 4, and 5 bearing compartments on the F100-PW-100 engine oil system are capped, which means they are sealed off from the outside environment. These compartments do not have a breather, which means they do not breathe air from the atmosphere. Instead, they rely on the scavenge system to remove any excess oil or contaminants from the compartments. Therefore, the correct answer is "Scavenge only."

The correct answer is "particles must be oil free for analysis to take place." SEM/EDX analysis is a technique used to analyze the composition of particles. In order to obtain accurate results, the particles being analyzed must be free of any oil contamination. Oil can interfere with the analysis process and lead to incorrect or unreliable results. Therefore, it is necessary to ensure that the particles are oil free before conducting SEM/EDX analysis.

A pneumatic starter requires sufficient volume and pressure of air source to operate properly. Volume refers to the amount of air available for the starter to use, while pressure determines the force with which the air is delivered. Therefore, both volume and pressure are necessary for the pneumatic starter to function effectively.

The engine monitoring system on the F119 engine consists of two components: the CEDU (Central Engine Data Unit) and the FADEC (Full Authority Digital Engine Control). The CEDU is responsible for collecting and processing data from various sensors and instruments throughout the engine, providing real-time information on its performance. The FADEC, on the other hand, is in charge of controlling and optimizing the engine's operation based on the data received from the CEDU. Together, these two components ensure the engine's efficient and reliable performance.

In an averaging type of EGT circuit, the thermocouples are connected in parallel. This means that the positive terminals of all the thermocouples are connected together, and the negative terminals are also connected together. This configuration allows for the average temperature to be measured across all the thermocouples, providing a more accurate reading.

The unit of an AC ignition system that develops 20,000 volts is the transformer. A transformer is a device that can increase or decrease the voltage of an alternating current. In this case, it is responsible for stepping up the voltage to 20,000 volts, which is necessary for the ignition system to create a spark and ignite the fuel-air mixture in the engine.

On the F-15 secondary power system CGB, the isolation decouplers are extended hydraulically. This means that hydraulic power is used to extend these decouplers.

The power to start the engines on an F-15 begins with the JFS (Jet Fuel Starter) and continues through the CGB (Combustion Gas Bypass) to the AMAD (Aircraft Mounted Accessory Drive). The AMAD is responsible for transmitting power from the engines to various aircraft systems, including the hydraulic and electrical systems. Therefore, it is the correct answer in this context.

Compressor bleed air is used for various purposes in an F110-GE-129 engine, including anti-icing, customer bleed, VSV actuator control, and low-pressure turbine cooling functions. However, the correct answer in this case is low-pressure turbine cooling functions. This means that compressor bleed air is specifically used to cool the low-pressure turbine in the engine.

The compressor bleed system reduces the probability of compressor stall in a dual-rotor engine by reducing the amount of air available to the N2 compressor. This is because compressor stall occurs when the airflow through the compressor becomes disrupted, leading to a loss of pressure and airflow. By bleeding off a portion of the air from the compressor, the system reduces the overall airflow and prevents it from reaching levels that could cause stall conditions in the N2 compressor.

The primary input power to the main ignition system is 28 VDC. This means that the ignition system requires a direct current power supply with a voltage of 28 volts. The other options, 28 VAC, 120 VAC, and 120 VDC, are not the primary input power for the ignition system.

A torch igniter is a system that employs a small combustion chamber to ignite the fuel in the augmentor (afterburner) duct. It is used to provide an initial flame to ignite the fuel-air mixture in the afterburner, allowing for increased thrust in certain aircraft engines. This system is commonly used in military aircraft for added power during takeoff or combat situations.

The correct answer is the CGB oil system. The CGB (Combustion and Gasoline Burner) oil system is responsible for supplying oil to the F-15 JFS (Jet Fuel Starter). The JFS is an auxiliary power unit used to start the aircraft's engines. The CGB oil system ensures that the JFS has a sufficient supply of oil to function properly.

The oil pressure in the F100-PW-100 engine varies with factors such as N2 (fan turbine speed), engine inlet oil temperature, and the condition of the oil nozzle. The oil nozzle condition refers to the state of the nozzle through which the oil is sprayed into the engine. If the nozzle is damaged or clogged, it can affect the oil pressure. Therefore, the condition of the oil nozzle is a crucial factor in determining the oil pressure in the engine.

The AFTLA obtains oil samples for analysis automatically from the manufacturer. This means that the manufacturer sends the oil samples to the AFTLA without the need for a specific request. This method ensures a regular and consistent supply of oil samples for analysis, allowing the AFTLA to conduct their analysis and testing efficiently.

The fuel flow transmitter in the F-15 is located in the engine bay.

The component in the F119 engine monitoring system that processes and stores various signals and data in resident memory is the CEDU (Central Engine Data Unit). This unit is responsible for monitoring and analyzing vibration signals, oil debris signals, oil level signals, condition monitoring, and fault information data. It plays a crucial role in ensuring the engine's performance and detecting any potential issues or faults.

The correct answer is "igniter plugs, and transformer." In a simple DC ignition system, the igniter plugs are responsible for producing the spark that ignites the fuel-air mixture in the engine. The transformer is used to step up the voltage from the DC power source to a higher voltage required for the spark. The AC to DC converter is not necessary in this system as it converts alternating current to direct current, which is not needed for the ignition process.

The JFS (Jet Fuel Starter) uses an annular combustion chamber. An annular combustion chamber is a type of combustion chamber where the air and fuel mixture is ignited in a ring-shaped chamber. This design allows for efficient and stable combustion, as the flame front propagates around the circumference of the chamber. The annular combustion chamber is commonly used in gas turbine engines, such as the JFS, due to its ability to provide uniform combustion and high combustion efficiency.

The power turbine overspeed switch is the component that provides an electrical safety cutoff for the JFS (Jet Fuel Starter) if the power turbine accelerates to a 110 percent overspeed condition. This switch is designed to detect excessive rotational speed of the power turbine and activate a safety mechanism to prevent further acceleration, ensuring the safety of the system.

Controlling turbine inlet temperature is the correct answer because it directly affects the amount of power generated by the engine. By regulating the temperature of the air entering the turbine, the engine can control the amount of energy extracted from the combustion process, which in turn affects the thrust production. This allows for precise control of the engine's performance and ensures optimal efficiency and power output.

The air turbine (impingement) starter is described as having the advantages of less weight and fewer moving parts than other starters. This means that compared to other types of starters, the air turbine starter is lighter in weight and has fewer components that can potentially wear out or malfunction. This makes it a more efficient and reliable option for starting an engine.

The CSD governor system is responsible for equalizing the load between generators operating in parallel. This means that it ensures that each generator is carrying an equal amount of the total load, preventing any generator from being overloaded or underloaded. By balancing the load, the CSD governor system helps to optimize the performance and efficiency of the generators, ensuring smooth and reliable operation. It also helps to prevent any single generator from being overworked, which can lead to mechanical stress and potential failures.

The correct answer is Three. This means that there are three independent circuits within an F100-PW-100 engine ignition system. This suggests that the ignition system is designed with redundancy, as having multiple independent circuits ensures that the engine can still be ignited even if one or two circuits fail. This is important for safety and reliability purposes, as it minimizes the risk of engine failure due to ignition system malfunctions.

The correct answer is 30. The question asks for the minimum rate at which the F100-PW-100 engine augmentor igniter plug ionizes sparks per second. Among the given options, 30 is the closest value to the minimum rate required.

The F100 engine augmentor's exhaust nozzle is variable to control both thrust and fan stall margin. By adjusting the exhaust nozzle, the engine can regulate the amount of thrust it produces as well as maintain a safe margin against fan stall. This allows for better performance and control of the engine during various operating conditions.

The PTO shaft used to drive the CSD is provided by the engine adapter. This adapter connects the engine to the CSD and allows the transfer of power from the engine to the shaft. Engine fittings, aircraft fittings, and aircraft adapter are not directly involved in providing the PTO shaft for the CSD.

Flap-type and iris-type variable-exhaust nozzle systems are used in jet engines to control the flow of exhaust gases. These systems need to be opened and closed as required. The correct answer states that air pressure is used for both types of systems. Air pressure is commonly used in aviation systems for various purposes, including actuating mechanisms. Therefore, it is logical to use air pressure to open and close both flap-type and iris-type variable-exhaust nozzle systems.

The slide-type resistor in the EGT circuit is used to calibrate the EGT indicator in the flight station. This means that it is used to adjust the EGT indicator so that it accurately displays the correct temperature readings. By using the slide-type resistor, the EGT indicator can be calibrated to ensure that it is providing accurate and reliable information to the pilot. This is important for monitoring the engine's exhaust gas temperature and ensuring that it is within safe operating limits.

The correct answer is CSD. The F-15 secondary power system does not include the CSD (Constant Speed Drive). The CSD is responsible for maintaining a constant speed of the aircraft's electrical generators. However, in the F-15, the secondary power system does not rely on a CSD for this purpose.

The MEC (Main Engine Control) schedules the variable vane positions on an F110-GE-129 engine based on the fan discharge temperature and core engine speed. This means that the MEC adjusts the positions of the variable vanes in response to these two parameters in order to optimize the engine's performance. The fan discharge temperature and core engine speed are important indicators of the engine's operating conditions, and adjusting the variable vane positions based on these parameters helps to ensure efficient and effective engine operation.