Tag Archives: datum

The datum used for balance calculations is:

A: chosen on the longitudinal axis of the aeroplane, but not necessarily between the nose and the tail of the aircraft
B: chosen on the longitudinal axis of the aeroplane, and necessarily situated between the nose and the tail of the aircraft
C: chosen on the longitudinal axis of the aircraft and necessarily situated between the leading edge and trailing edge of the wing
D: chosen on the longitudinal axis of the aircraft, and always at the fire-wall level

 

 

 

 

 

 

 

 

Answer: A

A load placed aft of the datum:

A: Has a positive arm and therefore generates a positive moment
B: Has a negative arm and therefore generates a negative moment and mass
C: Has a negative arm and therefore generates a negative moment but a positive mass
D: Has a positive arm and therefore generates a positive moment but negative mass

 

 

 

 

 

 

 

 

Answer: A

The datum is a reference from which all moment (balance) arms are measured. Its precise position is given in the control and loading manual and it is located

A: at a convenient point which may not physically be on the aircraft.
B: at or near the forward limit of the centre of gravity.
C: at or near the focal point of the aircraft axis system.
D: at or near the natural balance point of the empty aircraft.

 

 

 

 

 

 

 

 

Answer: A

In centre of gravity calculations the datum is

A: The horizontal reference used to calculate the helicopter’s empty centre of gravity
B: The fixed reference about which moments are taken to calculate the position of the centre of pressure
C: The point through which the centre of gravity acts
D: The fixed reference about which moments are taken to calculate the position of the centre of gravity

 

 

 

 

 

 

 

 

Answer: D