CDC Volume 2

A barometer is used to measure barometric pressure. Barometric pressure is the pressure exerted by the atmosphere at a certain location. A potentiometer is used to measure electrical potential difference, a psychrometer is used to measure humidity, and a pyrometer is used to measure high temperatures. Therefore, a barometer is the most suitable instrument for measuring barometric pressure.

The statement describes Bernoulli's principle, which states that as the velocity of a fluid increases, its pressure decreases. In the context of an airfoil, the air moving over the curved upper surface of the airfoil has a higher velocity, resulting in lower pressure compared to the slower-moving air underneath. This pressure difference creates lift, allowing the airfoil to generate upward force and fly.

Inertia is the correct answer because it refers to the tendency of an object at rest to stay at rest and the tendency of an object in motion to remain in motion in a straight line and at the same speed. Inertia is a fundamental property of matter and is related to the mass of an object. Objects with more mass have greater inertia, making it harder to change their state of motion. This concept is described by Newton's First Law of Motion.

The stationary vanes positioned between rotor discs in a compressor are used to direct air and increase pressure. These vanes act as guide vanes, redirecting the airflow and ensuring that it enters the rotor discs at the correct angle. By doing so, they help to increase the efficiency of the compressor by directing the air in the desired direction and increasing its pressure as it passes through the rotor discs.

The turbine section of a jet engine keeps the compressor rotating. As the high-pressure air from the compressor enters the turbine, it spins the turbine blades, which are connected to the same shaft as the compressor. This rotation helps to drive the compressor and maintain the continuous flow of air through the engine.

The fuel control is responsible for metering the fuel for combustion in the engine. It regulates the flow of fuel into the combustion chamber, ensuring the correct fuel-to-air ratio for efficient combustion. This component plays a crucial role in maintaining engine performance and optimizing fuel efficiency.

The most common type of fuel nozzle system is pressure atomizing. This system uses pressure to atomize the fuel, breaking it down into small particles for efficient combustion. It is widely used in various applications, such as in gas turbines, industrial burners, and oil-fired boilers. The pressure atomizing system offers better fuel efficiency and control, resulting in improved combustion performance and reduced emissions.

Before inspecting new jet engine bearings, it is necessary to remove the preservative coating. This is because the preservative coating is applied to protect the bearings during storage and transportation. However, it can interfere with the inspection process and potentially hide any defects or issues that may be present. Therefore, removing the preservative coating allows for a thorough inspection of the bearings to ensure their quality and functionality.

The recommended method of heating inner races of bearings before installing them is a hot-oil bath. This involves immersing the bearings in hot oil to heat them up uniformly and expand them for easier installation. This method ensures that the bearings are heated to the correct temperature without causing any damage or distortion. It is a commonly used and effective method in industries where precise and proper installation of bearings is crucial for their performance and longevity.

The overall reduction ratio of the RGB's main reduction gear train on the T56 is 13.54 to 1. This means that for every 13.54 rotations of the input shaft, the output shaft will rotate once. This reduction ratio indicates that the gear train is designed to reduce the speed and increase the torque of the output shaft compared to the input shaft.

A divergent duct refers to a duct that gradually increases in size along its length. As the gas passes through this type of duct, the cross-sectional area expands, causing the velocity of the gas to decrease. According to Bernoulli's principle, as the velocity decreases, the pressure of the gas increases. Therefore, a divergent duct decreases the velocity and increases the pressure of a gas as it passes through.

The combustion section of a jet engine is responsible for introducing and burning fuel. This is where the fuel is mixed with compressed air and ignited, producing a high-temperature and high-pressure gas. This gas then expands and passes through the turbine, which converts the energy into mechanical work to drive the compressor and other engine components. The combustion section is crucial for generating the necessary thrust to propel the aircraft forward.

The purpose of the exhaust duct is to straighten the exhaust gas flow. Straightening the flow helps to improve the efficiency of the exhaust system by reducing turbulence and allowing for a more streamlined and uniform flow of gases. This can help to optimize the performance of the engine and reduce any restrictions or backpressure in the exhaust system.

The most commonly used tools for removing bearings are arbor presses and bearing pullers. Arbor presses are used to apply pressure and force to remove the bearing from its housing, while bearing pullers are designed specifically to grip and remove bearings from shafts or housings. Both tools are essential for safely and effectively removing bearings without causing damage to the surrounding components.

The radial drive shaft on an F108 engine connects the core engine to the accessory drive assembly. This assembly is responsible for driving various accessories such as generators, pumps, and compressors. It transfers power from the engine to these components, allowing them to function properly. Without the accessory drive assembly, the engine would not be able to power the necessary systems and accessories required for its operation.

The sea level atmospheric pressure at "standard day" conditions is 14.7psi. This is considered the average pressure at sea level under normal weather conditions. It is commonly used as a reference point for measuring atmospheric pressure.

After a failed start, the fuel that accumulates is drained overboard by the drain system. This is done to remove any excess fuel that may have built up during the unsuccessful start. Draining the fuel overboard ensures that it does not remain in the system and potentially cause further issues.

The correct answer is "unshrouded." In jet engines, the three types of turbine and vane assemblies used are impulse, reaction, and unshrouded. Impulse turbines convert the kinetic energy of the gas into mechanical energy through a nozzle and rotor blades. Reaction turbines, on the other hand, convert both the kinetic and pressure energy of the gas into mechanical energy through the rotor blades. Unshrouded refers to the design of the turbine blades, where they are not enclosed or covered by a shroud.

When handling jet engine bearings, it is important to change cotton gloves frequently because they can get soaked with sweat. This is because the work environment for handling jet engine bearings can be hot and physically demanding, causing the person's hands to sweat. If the gloves become soaked with sweat, they can become uncomfortable and less effective in providing a good grip and protection. Changing the gloves regularly ensures that the person maintains a dry and comfortable grip while handling the bearings, reducing the risk of accidents or damage to the equipment.

The total gear reduction ratio of the RGB is 13.54 to 1. This means that for every 13.54 rotations of the input gear, the output gear will rotate once. This indicates a significant reduction in speed and an increase in torque, making it suitable for applications that require high torque output.

Vane-type fuel pumps used in jet engines are similar to sliding vane air compressors. Both types of pumps use a series of vanes that slide in and out of slots in a rotor. As the rotor spins, the vanes create chambers that draw in and compress air or fuel. This design allows for efficient and reliable pumping of fluids in high-pressure and high-temperature environments, making it suitable for both jet engines and air compressors.

The parts on a can annular combustion section must be removed in a specific order because of the combustion chamber crossover tubes. These tubes connect the individual combustion chambers within the can annular section, allowing for the proper flow and mixing of air and fuel. Removing the crossover tubes before other components could disrupt the flow and cause issues with combustion efficiency. Therefore, it is important to follow a specific order to ensure the proper functioning of the combustion section.

The major sections of a turbo prop engine are the power unit, torquemeter assembly, and RGB assembly. The power unit is responsible for generating the power needed to drive the engine. The torquemeter assembly measures the torque produced by the engine. The RGB assembly, which stands for Reduction Gearbox, is an important component that connects the power unit to the propeller. It helps to reduce the high rotational speed of the power unit to a suitable speed for the propeller, allowing for efficient propulsion. The compressor assembly and combustion assembly are not mentioned as major sections in this context.

The three major sections of all jet engines are the compressor, combustion, and turbine. The compressor section compresses incoming air, the combustion section mixes the compressed air with fuel and ignites it to create high-pressure gases, and the turbine section uses these high-pressure gases to drive the compressor and provide thrust. The turbine is responsible for extracting energy from the high-pressure gases and converting it into mechanical energy to power the engine.

Excessive bearing wear can usually be detected by roughness of the metal. When a bearing is excessively worn, the metal surfaces become uneven and lose their smoothness. This roughness can be felt by running a finger along the metal surface or observed visually. It is an indication that the bearing is no longer functioning properly and may need to be replaced. Pits and bands may also be present in worn bearings, but roughness of the metal is a more reliable and direct indicator of excessive wear. Misalignment can cause bearing wear, but it is not a specific indicator of excessive wear.

The heat content per pound of kerosene is measured in BTUs (British Thermal Units). The correct answer is 18,500 BTUs. This means that for every pound of kerosene, there is a heat content of 18,500 BTUs.

After air is drawn into the guide vanes of a centrifugal compressor, it is subjected to two forces: rotational and centrifugal. The rotational force is caused by the spinning motion of the impeller, which imparts a swirling motion to the air. The centrifugal force is a result of the air being pushed outward due to the curved shape of the impeller blades. These two forces work together to increase the velocity and pressure of the air as it passes through the compressor.

Swirl type fuel nozzles are designed to create a swirling motion in the fuel-air mixture, which enhances the mixing process and promotes better combustion. This leads to a more efficient and intense burning of the fuel, resulting in a higher flame speed. Therefore, swirl type fuel nozzles are typically used to provide a high flame speed.

The reduction geartrain is responsible for reducing the engine rotor speed to the RPM required for accessories. This component is designed to decrease the rotational speed and increase torque, allowing the engine to efficiently power various accessories such as alternators, water pumps, and air conditioning compressors. By using a series of gears with different sizes, the reduction geartrain effectively slows down the engine's high-speed rotation to match the specific requirements of the accessories.

The Tt2 is located in the fan inlet guide vane case at the 5:30 position on a F119-PW-100 engine.

The given statement describes Newton's 2nd law of motion. According to this law, when an unbalanced force is applied to an object, it will accelerate in the direction of the force. The acceleration is directly proportional to the force and inversely proportional to the mass of the object. This law is commonly expressed as F = ma, where F is the force, m is the mass, and a is the acceleration.

The turbine stator directs the gases onto the first stage turbine wheel blades in a jet engine. It is responsible for controlling the flow of gases and ensuring that they are directed towards the turbine blades with the correct angle and velocity. The turbine stator acts as a stationary component in the engine and works in conjunction with the rotating turbine blades to extract energy from the gases and convert it into mechanical power.

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 is responsible for directing the flow of gases towards the turbine wheel, ensuring efficient energy transfer and propulsion. It helps to maintain a steady flow of gases and maximize the performance of the turbine wheels.

Directing air around the plug helps prevent igniter plug fouling. This is because when air is directed around the plug, it helps to cool the plug and prevent the build-up of deposits that can cause fouling. By keeping the plug clean and free from deposits, it ensures efficient ignition and prevents any issues that may arise from fouling, such as misfires or engine performance problems.

The excess air that is not burned in the combustion section is used to cool the burner surfaces. This is important because the combustion process generates a significant amount of heat, and if the burner surfaces are not cooled, they can become damaged or even melt. By using the excess air for cooling, the burner surfaces can maintain their integrity and continue to function properly.

The purpose of an augmentor (afterburner) in a jet engine is to increase the basic engine thrust. The augmentor works by injecting additional fuel into the exhaust stream and igniting it, which creates a high-velocity jet of hot gases. This jet of gases adds extra thrust to the engine, increasing its overall power output and allowing the aircraft to achieve higher speeds or perform maneuvers that require additional thrust.

The stationary (stator) vane blades on the T56 compressor are used to increase pressure. These vane blades are strategically placed in the compressor to redirect the airflow and create a higher pressure zone. By increasing the pressure, the compressor is able to deliver more compressed air to the combustion chamber, resulting in improved engine performance.

The primary airflow in the F108 engine is through the booster, core engine, and low-pressure turbine. The accessory gearbox, on the other hand, is not a component through which the primary airflow passes. It is responsible for driving various accessories such as generators, hydraulic pumps, and fuel pumps.

The divergent design of a diffuser increases air pressure. A diffuser is a device that is used to slow down and expand the flow of a fluid, in this case, air. The divergent design causes the cross-sectional area of the diffuser to increase gradually, which leads to a decrease in flow velocity. According to Bernoulli's principle, as the flow velocity decreases, the pressure increases. Therefore, the divergent design of a diffuser increases air pressure.

Nicks are a type of defect that appears on bearings as a result of bearing parts striking together. Nicks are small, shallow cuts or notches on the surface of the bearing. They can occur due to improper handling, installation, or operation of the bearing. Nicks can lead to increased friction, reduced performance, and premature failure of the bearing. Regular inspection and maintenance can help identify and address nicks before they cause significant damage to the bearing.

The secondary airflow on the F108 engine produces 80% of the total engine thrust.

When small particles of foreign material become lodged between the rollers of bearings, it can cause grooves to appear as a type of defect. These grooves are formed due to the continuous rolling action of the particles against the bearing surface, resulting in a worn-out and uneven surface. This can lead to reduced performance and efficiency of the bearing, potentially causing further damage if not addressed.

When the rectangular teeth on the exciter wheels are aligned at zero torque, it means that there is no torque being transmitted. This alignment indicates that the torque being measured is zero, and the torquemeter is in a neutral or idle state. This is the point where the exciter wheels are in phase, as they are synchronized and not exerting any torque on the torque shaft.

The type of horsepower that is delivered to the propeller for useful work is brake horsepower. Brake horsepower refers to the actual power output of an engine or motor, after accounting for any losses due to friction or other factors. It represents the power available to do useful work, such as turning a propeller in this case.

The correct answer is that the impeller is forged as a single unit. This means that the impeller is manufactured as one solid piece, rather than being assembled from multiple parts. This constructional feature ensures that the impeller is strong and durable, as there are no weak points or joints where it could potentially fail. Additionally, forging the impeller as a single unit allows for better balance and efficiency in the centrifugal compressor.

The T700 engine AGB routes oil and fuel through internal passages. These internal passages are designed within the engine to allow the flow of oil and fuel, ensuring proper lubrication and fuel supply to the engine components. Using internal passages helps to maintain the integrity and efficiency of the engine system by keeping the oil and fuel contained within the engine itself, rather than relying on external lines or passages that could be more susceptible to damage or leakage.

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, such as the fan and augmenter. Mounting the stator generator on the gearbox allows for efficient power generation and distribution within the engine system.

When blending 4th stage compressor blades on an F100-PW-220 engine, the maximum number of blends allowed on any single edge is 2.

A turbo prop uses the method of accelerating a large mass of air by a small amount to produce thrust. This is achieved by using a gas turbine engine to drive a propeller. The engine compresses and heats the air, which is then mixed with fuel and ignited. The resulting hot gases expand and flow through a turbine, which drives the compressor and the propeller. As the propeller spins, it accelerates a large mass of air behind it, creating thrust and propelling the aircraft forward.

The T700 engine consists of four modules: the accessory section, compressor section, combustion section, and power turbine section.