Thanks Steve.

Seems that having the right hardware and software makes all the difference.

I my attempts the phase signal was all over the place. That's why I moved to adding a nut. Appears than one needs two channels being sampled simultaneously: trigger pulse and accelerometer, to get proper phase info?

Can you explain the prop "3x (blade)" ? Some kind of air interaction between prop, airframe and ground? In flight the air would quickly move past the prop, sitting still on the ground one could imagine some standing waves?

Also,� why does so much engine vibration remain (relative to prop's)? I think you mentioned that you first balanced the engine and then the prop.

Finn

On 3/18/2021 9:45 PM, Steven W. Boese SBoese@uwyo.edu wrote: