ATPL Principles of Flight - Class 13: Controls.

Summary

In this educational video, Grant explores the principles of flight, focusing on aircraft control surfaces. He explains how ailerons, elevators, and rudders manipulate airflow to achieve pitch, roll, and yaw, allowing pilots to maneuver. The video also covers the concept of 'feel' in controls, aerodynamic balances, tabs, and the importance of trim systems. Additionally, it touches on advanced control concepts like stabilators, rudder trim systems, and spoilers, providing a comprehensive understanding of how aircraft control surfaces work.

Takeaways

• ✈️ The main aircraft controls manipulate airflow to achieve maneuverability around three axes: pitch, roll, and yaw.
• 📉 Ailerons control roll by creating unequal lift on the wings, while elevators manage pitch, and rudders handle yaw.
• 🔄 Control surfaces work by changing the camber of the wing, similar to flaps, to alter lift distribution and generate force.
• 📚 This class connects theoretical concepts with practical applications, emphasizing the importance of control surfaces in flight.
• 🔧 The 'feel' of controls is due to the aerodynamic forces generated when surfaces are deflected, creating a resisting moment.
• 🛠 Aerodynamic balances like inset hinges, horn balances, and internal balances are used to reduce the feel moment and make controls easier to manipulate.
• 📉 Control tabs, including balance tabs, anti-balance tabs, and servo tabs, are used to adjust the feel and response of control surfaces.
• ⚖️ Trim systems allow pilots to adjust the neutral point of control surfaces for ease of control and to counteract effects like a forward center of gravity.
• 🚀 High-speed aircraft often use powered or power-assisted controls due to the high forces involved, sometimes incorporating artificial feel systems.
• 🏞️ Adverse yaw can occur during roll maneuvers, but it can be mitigated by adjusting aileron deflection to balance drag.
• 🏁 Spoilers serve dual roles on larger aircraft, assisting in roll control and acting as speed brakes to increase drag and reduce speed.

Q & A

What are the three main axes of aircraft movement?

The three main axes of aircraft movement are the normal axis, the longitudinal axis, and the lateral axis. These axes are responsible for pitch, roll, and yaw movements, respectively.

What is the primary control surface for roll movement?

The primary control surface for roll movement is the aileron, located on the wings.

How does the elevator control the pitch of an aircraft?

The elevator, located at the tail, controls the pitch by deflecting up or down, which changes the resultant force and causes the aircraft to rotate around the lateral axis.

What is the role of the rudder in controlling an aircraft?

The rudder, also located at the tail, controls the yaw by deflecting to the left or right, which rotates the aircraft around the center of gravity.

How do control surfaces manipulate airflow to maneuver an aircraft?

Control surfaces manipulate airflow by modifying the camber, similar to flaps, which changes the lift distribution and creates a large change in the local coefficient of lift, resulting in a force that allows the aircraft to rotate around its center of gravity.

What is the purpose of the aerodynamic balances in control surfaces?

Aerodynamic balances are used to reduce the feel moment, which is the resistance felt by pilots when deflecting control surfaces. This makes it easier for pilots to manipulate the controls, especially at higher speeds.

What is the function of a servo tab in aircraft control?

A servo tab is a small control surface that moves in response to the pilot's input, which in turn moves the main control surface. This allows the pilot to feel only the force in the servo tab, making control surface manipulation easier.

Why is it important to have a rudder trim system in an aircraft?

A rudder trim system is important to adjust the neutral point when flying asymmetrically, such as when one engine is out, to prevent the risk of fin stall and to maintain directional control.

How do spoilers assist in roll control on large aircraft?

Spoilers assist in roll control by deflecting up on the same side as the aileron that deflects up, or the downward going wing, creating a larger imbalance of lift between the wings and aiding in the rotation.

What is the concept of adverse aileron yaw and how is it managed?

Adverse aileron yaw occurs when the wing that travels up through the air, due to increased lift, also experiences more induced drag, causing a yawing motion towards that wing. It is managed by adjusting the levels of deflection on either side to balance the drag forces.