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Theory of Flight

6.02 Flight Controls References: FTGU pages 30-31

6.02 Flight Controls

•  MTPs: – Axes of an Airplane – Movements – Function of the Controls – Flutter – Balancing Controls

Review

•  Label the airplane!

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Review

•  What kind of construction are these?

Review

•  How would you describe these aircraft?

Review

• Whatdothefollowingtermsmean?– Wingspan–  Chord–  Planform– AspectRa;o– AngleofIncidence–  Rela;veAirflow– AngleofA?ack– Airfoil–  Camber

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Axes of an Airplane

Movements

Movements

•  Roll – movement around longitudinal axis

•  Pitch – movement around lateral axis

•  Yaw – movement around vertical/normal axis

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Function of the Controls

Ailerons cause movement around the longitudinal axis This movement is called roll.

Function of the Controls

•  Ailerons are controlled using the control column

•  Control column RIGHT = right wing down

•  Control column LEFT = left wing down

Function of the Controls

The elevator controls movement about the lateral axis This movement is called pitch.

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Function of the Controls

•  Elevators are controlled using the control column

•  Control column FORWARD = nose down

•  Control column BACK =nose up

Function of the Controls

•  An alternative to the elevator is the stabilator –  It is controlled the same way the elevator is –  The entire horizontal stabilizer moves to act as an

elevator

Function of the Controls

The rudder controls movement around the vertical axis. This movement is called yaw.

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Function of the Controls

•  The rudder is controlled using the rudder pedals Right rudder pedal = yaw right Left rudder pedal = yaw left

Flutter

•  What is flutter?

• Rolling or weaving motion arising from deflection of a part of the airplane structure that causes the air forces on it to change in synchronism with its natural period of vibration

• Control surfaces must be balanced properly to prevent flutter!

Balancing Controls

•  Balancing control surfaces to help pilots move them

•  Examples: –  Inset hinge balance – Rudder horn – Aileron hinge axes

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Balancing Controls

Balancing Controls

•  Addition of mass (usually made of lead) to control surfaces to prevent flutter

•  Example: – Lead mass added to rudder horn of glider

Balancing Controls

•  A control surface has balance about it’s centre of gravity without airflow over it

•  Improper weight distribution can cause flutter

•  Static balance must be checked when control surface is repainted

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Confirmation

•  Draw and label the three aircraft axis. •  Which movement occurs around each axis? •  Which control surface is used for each movement?

F-35B Hovering