How Much Do You Know About Helicopter? Helicopter Quiz

External load operators are required to comply with an additional Federal Aviation Regulation (FAR) that specifically applies to external loads. This means that they must adhere to specific rules and guidelines when operating with external loads, ensuring the safety and proper handling of these loads during flight. Therefore, the statement "External load operators have to comply with an additional FAR which applies to external loads" is true.

PMD stands for Preventative Maintenance Daily. This acronym refers to a regular inspection and maintenance routine that aims to prevent equipment failure and ensure optimal performance. It involves daily inspections of various components and systems to identify potential issues and address them before they escalate. The PMD process helps to increase the lifespan of equipment, reduce downtime, and enhance overall operational efficiency.

The purpose of the free wheeling unit in a helicopter drive system is to disconnect the rotor whenever the engine stops or slows below the equivalent of rotor RPM. This is important because the rotor relies on the engine's power to maintain its speed and rotation. If the engine stops or slows down, the free wheeling unit allows the rotor to continue spinning independently, preventing it from abruptly stopping and causing damage to the helicopter.

The angle of attack refers to the acute angle formed between the chord line of the rotor and the relative wind. It is an important concept in aerodynamics as it determines the lift and drag forces acting on the rotor. A higher angle of attack increases lift but also increases drag, while a lower angle of attack reduces lift but also reduces drag. Therefore, understanding and controlling the angle of attack is crucial for achieving optimal performance and stability in rotorcraft.

The fastest moving point on the blade is the tip. This is because the tip of the blade has a larger radius than the root, resulting in a greater linear velocity as the blade rotates. Therefore, the tip moves faster compared to the root.

The auxiliary (tail) rotor of a helicopter allows the pilot to control the torque generated by the main rotor, which helps to counteract the tendency of the helicopter to rotate in the opposite direction of the main rotor. Additionally, the tail rotor also provides directional control by allowing the pilot to adjust the yaw position of the helicopter. Therefore, the correct answer is torque and directional control.

The correct answer is "Torque direction is the opposite of rotor blade rotation." This means that as the rotor blades rotate in one direction, the torque produced by the engine causes the helicopter body to rotate in the opposite direction. This is due to the principle of conservation of angular momentum. As the rotor blades push air downwards, the helicopter body experiences an equal and opposite reaction, causing it to rotate in the opposite direction.

The cyclic pitch control of a helicopter is responsible for tilting the tip path plane in the direction of desired movement. This means that it adjusts the angle of the rotor blades as they rotate, allowing the helicopter to move in different directions. By changing the angle of the blades, the cyclic pitch control can create imbalances in lift across the rotor disc, resulting in the desired movement of the helicopter.

The chord of a main rotor is the straight line distance between the leading edge and the trailing edge of the rotor blade. This measurement helps determine the aerodynamic characteristics of the blade and is important for calculating lift and drag forces. The other options, blade tip to blade tip and blade tip to blade butt, do not accurately measure the chord length of the rotor blade.

When the lift of an airfoil increases, the drag also increases. This is because as the lift increases, the airfoil experiences more resistance from the air, leading to an increase in drag. The relationship between lift and drag is directly proportional, meaning that as one increases, the other also increases. Therefore, when the lift increases, the drag will also increase.

The freewheeling unit is a crucial component in a helicopter's transmission system. Its purpose is to automatically disengage the rotor from the engine in case of an engine failure. This is important because if the engine fails, the rotor would still be spinning due to its inertia. If the rotor remained connected to the engine, it could cause significant damage or even lead to a catastrophic failure. By automatically disengaging the rotor, the freewheeling unit allows the pilot to maintain control and perform a safe autorotation landing.

The throttle is attached to the top or grip of the collective. The collective is a control in helicopters that is used to change the pitch angle of all the main rotor blades simultaneously. By attaching the throttle to the top or grip of the collective, the pilot can easily control the engine power while also adjusting the pitch angle of the rotor blades. This allows for precise control of the helicopter's lift and speed.

A fully articulated rotor head compensates for dissymmetry of lift through the employment of a flapping hinge. The flapping hinge allows the rotor blades to move up and down, adjusting their angle of attack as they rotate. This movement helps to balance the lift across the rotor disc, preventing one side from experiencing more lift than the other. By allowing the blades to flap, the rotor head ensures that the helicopter remains stable and maintains a consistent lift throughout its rotation. The swivel plate and coning device do not directly address the dissymmetry of lift issue, making the flapping hinge the correct answer.

The Bell maintenance manual Airworthiness Limitation Schedule provides the retirement schedule for specific helicopter parts. This schedule outlines the recommended lifespan or usage limits for various components of the helicopter, ensuring that they are replaced or retired before they reach a point where they may become unsafe or unreliable. Following this schedule helps maintain the airworthiness and safety of the helicopter by ensuring that parts are replaced at the appropriate intervals.

The correct answer is cyclic pitch control. In a helicopter, movement about the longitudinal axis, also known as roll, is controlled by the cyclic pitch control. This control adjusts the pitch of the rotor blades as they rotate around the mast, causing a difference in lift on each side of the helicopter. By manipulating the cyclic pitch control, the pilot can tilt the helicopter in the desired direction, thus achieving roll movement. The collective pitch control is responsible for controlling the overall lift of the helicopter, while the tail rotor pitch control is used to counteract the torque produced by the main rotor.

The vertical flight of a helicopter is controlled by collective pitch changes. Collective pitch refers to the angle of attack of all the blades on the main rotor, which can be collectively adjusted. By increasing or decreasing the collective pitch, the pilot can change the lift generated by the rotor blades, allowing the helicopter to ascend or descend vertically. This control mechanism is essential for controlling the helicopter's altitude during vertical flight. Cyclic pitch changes, on the other hand, control the helicopter's movement in different directions, while changing the RPM of the main rotor affects the overall power output but does not directly control vertical flight.

In a helicopter in forward flight, the main rotor disk can be tilted in the desired direction to change the direction of the helicopter. This is achieved by adjusting the angle of the rotor blades, which allows the helicopter to move in the desired direction. Changing the pitch of the main rotor blades or the rotor RPM alone would not be sufficient to change the direction of the helicopter in forward flight.

The strobe method is used to check tracking in the air. This method involves using a strobe light to create a series of flashes that illuminate the aircraft's propeller or rotor blades. By observing the pattern of the flashes, it is possible to determine if the blades are tracking correctly or if there is any imbalance or misalignment. This method is commonly used in aviation maintenance to ensure the safe operation of aircraft.

In a hovering helicopter equipped with a tail rotor, altitude control is maintained by changing the pitch of the main rotor blades. By altering the pitch of the main rotor blades, the lift generated by the rotor system can be adjusted, allowing the helicopter to ascend or descend. The tail rotor, on the other hand, is responsible for controlling the helicopter's yaw or rotation. Therefore, it is the pitch of the main rotor blades that directly affects the altitude control of the helicopter.

The purpose of the swash plate is to transmit control inputs to the rotor head. This means that it is responsible for transferring the pilot's control inputs, such as cyclic and collective inputs, to the rotor blades, allowing the helicopter to maneuver and change its altitude. The swash plate is a crucial component in the helicopter's control system, enabling the pilot to have direct control over the rotor blades and ultimately the movement of the helicopter.

When the cyclic control is moved, it causes the swashplate to tilt. The swashplate is a mechanism used in helicopters to control the pitch of the rotor blades. By tilting the swashplate, the angle of attack of the rotor blades can be changed, which in turn affects the lift and direction of the helicopter. Therefore, when the cyclic control is moved, it directly influences the tilting of the swashplate.

If the tail rotor of a helicopter fails to compensate accurately for the torque of the main rotor, it suggests that the tail rotor is not properly aligned or adjusted. This misalignment or incorrect rigging of the tail rotor can cause it to be inefficient in countering the torque produced by the main rotor, leading to handling and stability issues for the helicopter.

In flight, rotor droop is overcome by centrifugal force and lift. When the rotor blades rotate, centrifugal force pushes them outward, counteracting the drooping effect. Additionally, lift is generated by the rotor blades as they move through the air, providing upward force and further compensating for rotor droop. These two forces work together to maintain the proper position and stability of the rotor system during flight.

An increase in pitch angle of the tail rotor blades on a helicopter causes the tail to pivot in the opposite direction of torque rotation around the main rotor axis. This is because the tail rotor generates thrust in the opposite direction of the main rotor's torque, creating a counteracting force. By increasing the pitch angle, the tail rotor blades increase their angle of attack, resulting in more thrust being generated in the opposite direction. This causes the tail to pivot in the opposite direction, helping to maintain the helicopter's stability and counteract the torque produced by the main rotor.

Tracking of helicopter rotor blades is normally done while the blades are rotating at a specific RPM and collective pitch angle. This is because the flexibility of the blades can cause them to bend or warp during rotation, which can affect their alignment. By tracking the blades while they are rotating, any misalignment or imbalance can be detected and corrected before the blades are installed. This ensures that the rotor system operates smoothly and efficiently, reducing vibrations and improving overall performance. Direct measurement from the fuselage structure to a specific blade station when the blade is parallel to the fuselage centerline is another method used for tracking, but the given answer focuses on the more common practice of tracking while the blades are rotating.

When main rotor blades do not cone by the same amount during rotation, it means that they are not following the same track or path. This can lead to an imbalance in the rotor system, affecting the stability and performance of the aircraft. Therefore, when the main rotor blades are not coning by the same amount, they are said to be out of track.

If a helicopter's retirement schedule is lost, it means that the information regarding when the helicopter is supposed to be retired is no longer available. In such a situation, it would be necessary to estimate the retirement times based on other available information or factors. Therefore, the statement "If a helicopter's retirement schedule is lost, times may be estimated" is true.

In a single rotor helicopter during forward horizontal flight, the advancing blade experiences a higher relative wind speed compared to the retreating blade. This is because the advancing blade is moving forward into the oncoming airflow, while the retreating blade is moving away from it. As a result, the advancing blade has a higher angle of attack, which is the angle between the chord line of the blade and the relative wind. Therefore, the angle of attack of the advancing blade is less than that of the retreating blade.

The ventral fin on a helicopter is designed to provide directional stability. This means that it helps the helicopter maintain a straight and steady flight path by counteracting any unwanted yawing or turning motions. By creating resistance to sideways movement, the ventral fin helps the helicopter stay on course and improves its overall maneuverability. Additionally, the ventral fin also helps to improve the helicopter's stability during hover and low-speed flight, making it an important component for safe and controlled helicopter operations.

In an all metal helicopter, the cable operated control system is rigged to the correct tension in a heated hangar. However, when the helicopter is operated in very cold weather, the aircraft structure and cables will become cold. As metal contracts in cold temperatures, the cables will shrink, causing the tension in the cables to decrease. Therefore, the cable tension will decrease when the aircraft structure and cable become cold. The presence of stainless steel cables will not have any effect on this decrease in tension.

In a single rotor helicopter during forward horizontal flight, the retreating blade experiences a higher angle of attack compared to the advancing blade. This is because the retreating blade is moving in the opposite direction of the helicopter's forward motion, resulting in a higher relative airflow speed and thus a higher angle of attack. This imbalance in angles of attack is necessary to maintain lift and stability during forward flight.

If a severe abnormal vertical vibration developed in a helicopter equipped with a two blade rotor system, it would indicate that the rotor blades are out of track. This means that the blades are not rotating in the same plane, causing an imbalance in the rotor system. This can lead to excessive vibrations and potential safety issues. Adjusting the track of the rotor blades is necessary to ensure smooth and balanced rotation, thereby reducing vibrations and improving the overall performance of the helicopter.

In a hovering helicopter equipped with a tail rotor, directional control is maintained by varying the pitch of the tail rotor blades. This is because the tail rotor generates a sideways force that counteracts the torque produced by the main rotor. By changing the pitch of the tail rotor blades, the pilot can adjust the amount of thrust generated by the tail rotor, thus controlling the direction of the helicopter. Tilting the main rotor disk in the desired direction or changing the tail rotor RPM alone cannot provide the necessary directional control.

The semi-rigid rotor system makes use of a seesaw system for flapping. In a seesaw system, the blades are connected to the rotor hub through a teetering hinge, allowing them to pivot up and down. This movement provides the necessary flapping motion for the rotor system, allowing the helicopter to generate lift and control its flight. The seesaw system allows for controlled and coordinated flapping of the blades, ensuring stability and maneuverability during flight.

The universal propeller protractor is a tool specifically designed to measure the blade pitch angle of a propeller. It is not used to measure degrees of blade flap travel or propeller track. Therefore, the correct answer is blade pitch angle.

In order to achieve spanwise static balance, weight may be added to the blade tip. This is because adding weight to the blade tip helps to redistribute the center of gravity and ensure that the blade is balanced along its span. By adding weight to the blade tip, any imbalances or uneven distribution of weight can be corrected, resulting in improved stability and performance of the blade.

A "Hard Card" refers to the individual record for a specific part. This means that it is a document or record that contains detailed information about a particular part, such as its history, maintenance, and any relevant certifications. It is used to track and document the life cycle and maintenance of the part, ensuring that it meets all necessary requirements and standards.

When the pitch angle of the tail rotor blades on a helicopter decreases, it causes the tail to pivot in the direction of torque rotation around the main rotor axis. This means that the tail will move in the same direction as the torque produced by the main rotor. This adjustment is necessary to maintain balance and stability in the helicopter during flight.

Ground resonance is a self-excited vibration that occurs in fully articulated rotors. This type of rotor system allows for a high degree of freedom and flexibility, with each rotor blade able to move independently. When the helicopter lands on an uneven surface or experiences an asymmetrical load, it can cause the rotor blades to become out of phase with each other. This can lead to a destructive vibration known as ground resonance, which can cause severe damage to the helicopter if not addressed promptly. Semi-articulated and semi-rigid rotors do not have the same level of flexibility and are less prone to ground resonance.

The correct answer is anti-torque pedals. In a helicopter, the anti-torque pedals are used to control the direction of the aircraft about its vertical axis. These pedals are located on the cabin floor and are operated by the pilot's feet. By applying pressure to the pedals, the pilot can adjust the pitch of the tail rotor blades, which counteracts the torque produced by the main rotor. This allows the helicopter to rotate left or right. The cyclic control is used to control the helicopter's movement in the forward, backward, and lateral directions, while the collective control adjusts the pitch angle of the main rotor blades to control the helicopter's altitude.

When an aircraft accelerates into forward flight, the synchronized elevator tends to lower the tail boom. This is because the synchronized elevator is responsible for controlling the pitch of the aircraft, and lowering the tail boom helps to increase the pitch angle. By lowering the tail boom, the elevator generates a downward force on the tail, causing the aircraft's nose to pitch up. This is necessary for maintaining stability and control during forward flight.

The greater down wash effect through the aft part of the main rotor disk compared to the forward part of the disk is known as transverse flow lift. This phenomenon occurs in helicopters during forward flight when the advancing blade experiences increased lift due to the higher airspeed, while the retreating blade experiences reduced lift due to the lower airspeed. As a result, there is a lateral flow of air from the advancing side to the retreating side, causing a greater down wash effect on the aft part of the rotor disk. This transverse flow lift helps to balance the lift distribution across the rotor disk and maintain stability during forward flight.

The tail rotor is responsible for providing sideways flight and compensation for torque. However, it is not involved in lateral control. Lateral control refers to the ability to maintain balance and stability during sideways movements. This is typically achieved through other control surfaces such as ailerons or wing flaps. Therefore, the tail rotor does not play a role in lateral control.

The elevator of a conventional helicopter is used to provide stability about the lateral axis. The lateral axis is an imaginary line that runs horizontally across the helicopter from wingtip to wingtip. By adjusting the angle of the elevator, the pilot can control the pitch of the helicopter, which determines whether the nose of the helicopter points up or down. This control is crucial for maintaining stability and controlling the helicopter's altitude during flight.

The purpose of checking main rotor blade tracking is to determine the flight path of the blades during rotation. This is important because any deviation in the flight path can indicate an issue with the rotor system, such as an out of balance condition or misalignment. By monitoring the flight path, maintenance personnel can identify and correct any problems, ensuring the safe and efficient operation of the rotor system.

When a main rotor blade flaps, there is a shift in the center of mass. This shift causes an increase in the blade's speed. This is because the shift in the center of mass creates an imbalance in the blade, causing it to rotate faster. Therefore, the correct answer is that the shift in the center of mass of a main rotor blade when it flaps has a tendency to speed the blade up.

An out-of-track helicopter main rotor would normally cause low frequency vertical vibration. This means that the rotor blades are not rotating in a perfectly circular path, causing an imbalance in the rotor system. This imbalance leads to a low frequency vibration that is felt vertically, meaning it causes an up and down motion. This type of vibration can be detrimental to the helicopter's stability and overall performance.

The term "sweeping the blade" refers to a rotor system in which the blades are allowed to flap and lead-lag, but are also constrained by a teetering hinge or other means to limit their movement. This is characteristic of semi-rigid rotors, which provide a balance between the flexibility of fully articulated rotors and the rigidity of rigid rotors. In fully articulated rotors, the blades have complete freedom of movement, while in rigid rotors, the blades are fixed and cannot flap or lead-lag. Therefore, the correct answer is semi-rigid rotors.

The main rotor drag brace is adjustable in order to balance the main rotor in a chordwise direction. This means that it can be modified or changed to ensure that the rotor is evenly balanced along its length, from the leading edge to the trailing edge. This adjustment is important for maintaining stability and control during flight, as any imbalance in the chordwise direction can affect the performance and handling of the rotor system.

When the tail rotor is out of spanwise balance, it means that the weight distribution of the rotor blades is uneven. This imbalance can cause the rotor to vibrate at a high frequency during operation. The vibrations can be felt throughout the aircraft and may affect its stability and performance. It is important to ensure that the tail rotor is properly balanced to prevent excessive vibrations and potential damage to the aircraft.