Getting rotor blades tracked to a state I call “butter smooth” is one part science and two parts magic. Anyone can learn the technical part of tracking rotor blades. The magic part requires at least a level 50 rotor blade mage, some pixie dust, and likely some sort of animal sacrifice. I’ve never inquired about the latter since I fear the truth.
With the Enstrom 280FX, there are three stages to the tracking process. First you want to get rid of any stick shake, then minimize vibration in hover and forward flight.
The picture to the right shows the cyclic with a vibration sensor. A second sensor mounted near the main rotor mast measures the rotor rpm. Vibration is measured at a particular rpm by the Vibrex 2000 (second picture on the right). It provides a vibration level in incidents per second (ips) and a clock angle. Lower ips means a smoother ride. The clock angle tells you which rotor blade should be adjusted to lower the ips. Adjustments to pitch links on each rotor blade change the track.
Pilot and mechanic measure ips and clock angle then adjust pitch links in an effort to reduce the level of vibration… rinse and repeat. Once the stick shake is within limits, the process repeats for blade track in hover and forward flight.
According to my mechanic (level 80 rotor blade mage) this was done in the past by raising a stick with chalk on it up in to the rotor blades while they were turning. The mechanic would then look at the marks on the blades after they stopped to figure out which blades to adjust. Yikes!