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Which formula below is correct for the generation of Centripetal Force (CPF)?
  • A
    CPF = (r x g) / (W x V²)
  • B
    CPF = (W² x V) / (r x g)
  • C
    CPF = (W x V²) / (r x g)
  • D
    CPF = (W x V² x r) / g

Refer to figure.
A helicopter, like any moving object, requires a sideward force to make it turn. In a normal turn, this force is supplied by banking the helicopter, so that Total Rotor Thrust (TRT) is tilted towards the centre of the turn. Thus, the force of TRT during a turn is separated into two components at right angles to each other:

  • One component, which acts vertically and opposite to the weight (gravity), is called the “Vertical component of TRT”.
  • The other, which acts horizontally toward the centre of the turn, is called the “Horizontal component of TRT” or "Centripetal Force (CPF)".

The CPF acts in opposition to the centrifugal force and the amount of CPF required to hold an aircraft in a turn is given by the following formula:

  • CPF = (W x V²) / (r x g)


  • W: Weight of the helicopter
  • V: speed
  • r: turn radius
  • g: gravitational constant of 9.81 m/s2

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