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Primary Flight Controls

All flight controls work through the center of gravity of the airplane.

Airplane aileron

Elevator​

Elevator forces

Controls rotation around the lateral axis, also provide downward pressure to counteract the rotational moment of the main wing.

  • The bell crank is a device that translates the forward/back motion of the yoke into the movement of the elevator.
  • The down-spring keeps the elevator neutral

T-tails​

  • Tail mounted on the top of the rudder
  • Tail is not out in the prop wash
  • Requires more motion of the flight controls since there is no prop air over the control surface
  • Risk of a "deep stall" because there's little airflow over the tail

Stabilator​

Stabilator

  • A "full flying surface"
  • Generates a lot of force quickly, more than an elevator
  • Easy to over-control since it generates a lot of force
  • Anti-servo tab, works against the movement of the elevator to counteract the over-control

Canard​

  • "Elevator" mounted on the nose of the airplane
  • Also not in the prop wash of the airplane
  • Provides "nose-up" force

Ailerons​

  • Controls the roll of the airplane around the longitudinal axis
  • Introduces adverse yaw due to induced drag on the upward aileron
    • Differential ailerons: The aileron can be lowered farther than it can be raised
    • Frise ailerons: A gap between the aileron the wing and aileron surface, helps create more drag when aileron is lifting
  • Coupled aileron/rudders: Mechanical linkage between rudder and ailerons, often with strings
  • Flaperons: Combination flap/aileron control surface
    • Relies on a mixer to combine input

Aileron

Rudder​

Provides yaw, or rotation around the vertical axis.

  • Cable-actuated, should hit rudder stops

V-tails​

  • "Ruddervators"
  • Also requires a mixer to mix rudders and elevators