The previous post stems from having run into a bad resonance at 2450 rpm immediately after installing new isolators. I was all set to record the vibration when the orientation problem was discovered. Since the accelerometer and data logger were already installed and ready to go, I recorded the correct isolator installation just for kicks.
2,300 rpm is super smooth, takeoff at 2,700 rpm is not far behind. Peak vibration levels are in the 2,500-2,600 rpm range.
The prop is currently very well balanced (0.02 ips) and never dominates the spectrum (38-45Hz). Peaks alternate between 1/2 order and second order. Results are attached.
If anyone is experiencing more vibration than
they would like with a dynamically balanced prop, it might be worth checking the orientation of the isolators. This can be done by external visual inspection. The pin location has a small bump-out in the rubber.
Chris Zavatson
N91CZ
360std