Measurement of Coupling Misalignment of a Driveshaft

A method for measuring coupling misalignment of a rotorcraft drive shaft, the rotorcraft drive shaft disposed between an engine and a pylon and configured to rotate at least one component of a rotor system in response to receiving rotational energy from the engine, the method comprising:

• providing a reference device and a sensor disposed on opposite sides of a flexible coupling coupled to the drive shaft and disposed between the engine and the pylon, the flexible coupling configured to rotate with the drive shaft and comprising a flexure portion configured to flex in response to a difference in alignment between the engine and the pylon;
• receiving, at the sensor, a signal from the reference device indicative of a distance between the reference device and the sensor;
• and
• generating a misalignment value in response to the signal.

A system for measuring coupling misalignment of a rotorcraft drive shaft, the rotorcraft drive shaft disposed between an engine and a pylon and configured to rotate at least one component of a rotor system in response to receiving rotational energy from the engine, the system comprising:

• a reference device;
• a sensor configured to receive a signal from the reference device indicative of a distance between the reference device and the sensor, the reference device and the sensor configured to be disposed on opposite sides of a flexible coupling coupled to the drive shaft and disposed between the engine and the pylon, the flexible coupling configured to rotate with the drive shaft and comprising a flexure portion configured to flex in response to a difference in alignment between the engine and the pylon;
• and
• a misalignment measurement system configured to generate a misalignment value in response to the signal.