Flight Controls: Overview
Primary Control Services
Controls that rotate the aircraft around its three axes:
- Elevator (Pitch / Lateral Axis).
- Ailerons (Roll / Longitudinal Axis).
- Rudder (Yaw / Normal Axis).
Secondary Flight Controls
Used to change the aerodynamic configuration or assist primary controls.
- Trim Tabs: Relieve control forces.
- Balance Tabs: Assist in moving the control surface (reduce force).
- Anti-Balance Tabs: Increase control feel (increase force).
- Flaps/Slats: High lift devices.
- Spoilers: Lift dumpers / Airbrakes.
Interaction
- Maneuverability vs Stability: A highly stable aircraft is harder to control (heavy controls). A highly maneuverable aircraft (like a fighter) is less stable.
- Control Reversal: At very high speeds, aeroelastic twisting of the wing can cause aileron reversal (deflecting aileron down twists the wing leading edge down, reducing lift instead of increasing it).