If there is any interest, an image of raw data is attached which was processed with FFT software to give the frequency and phase angle information like that shown recently.

It should demonstrate the challenge involved in working with the raw data directly.  The green trace is the position sensor signal with a transition at each prop revolution.  I, for one, cannot see evidence of a one-per-prop-revolution vibration in the raw data.  The beat with a frequency of about 7 prop revolutions is a result of the reduction drive 2.85 ratio, each blade of the 3 blade prop, and the fact that neither the engine nor the prop are perfectly balanced.

The following link should lead to images of a comparison of the raw data before and after trying to balance the prop, the setup, and the weights added to the prop.

Steve Boese

Sent from my iPad