Rotor Tracking and Balance

Out of Track Rotor

As the rotor blades rotate around the mast, both blade tips should follow the same path, known as the tip path plane.

If the blade tips follow different paths, the rotor is said to be out of track, which can cause a noticeable vertical vibration or bouncing sensation during flight.

An out-of-track rotor requires inspection and adjustment at the rotor head to ensure both blades follow the same path. This should be carried out in accordance with the manufacturer's instructions.

Stick Shake

Stick shake is a vibration felt through the control stick and can indicate an imbalance or mechanical problem within the rotor system.

As the rotor blades rotate, their combined centre of gravity should remain aligned with the axis of rotation. Any imbalance can produce vibrations that are transmitted through the control stick.

Possible causes of stick shake include:

• Rotor blade imbalance – Uneven weight distribution between the blades can cause vibration. Rotor blades are normally balanced during manufacture. Incorrect blade alignment can also cause an imbalance. This alignment is checked through a process known as stringing, which ensures the blades are correctly aligned with each other and the centre of the hub.