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There are three axes of rotation for an aircraft. These axes all intersect at which point?

  • A

    The centre of pressure.

  • B

    The centre of gravity.

  • C

    The centre of rotation.

  • D

    Midpoint of the chord line.

Refer to figure.
When in flight, the aircraft is controlled about one point - The centre of gravity (CG). All three axes of rotation therefore pass through this point: the lateral, longitudinal and normal axis. When aerodynamic forces are created using any controls, or from any stabilising forces, they create rotation about the CG. 

The centre of pressure → INCORRECT. This is the point through which the sum of aerodynamic reaction forces seem to act.

The centre of gravity → CORRECT

The centre of rotation → INCORRECT. This is not the name used to describe the point about which rotation occurs for an aeroplane, although it is technically true. Because rotation all occurs around the CG, we only refer to the centre of gravity and not a “centre of rotation”. 

Midpoint of the chord line. → INCORRECT. Firstly, this is not a 3D point, but an axis. Secondly, it is just a random location and isn't significant. 

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