I have a Pro unit mounted on my Gaui Hurricane plastic frame stretched. It has been flying for over a year using 500 mm blades and has been great. I had some ESC issues that caused two crashes which has resulted in replacing the ESC with a HW 100 v3 unit which seems to have no issues feeding power to the servos. Both crashes were power loss - rescue mode got the heli flat so the damage was skids, boom, etc. and amazingly not blades, with a "free fall" (my auto ability is nearly non-existent).

Since the crashes I have been fighting a vibration which shows in the skids, tail boom support pipes, CF tail servo push rod, and tail vertical fin. At various times all are moving so fast they have a blurry look when watching while hovering.

I have tried swapping the tail assemblies, new tail belts, etc. I'm currently setup with a long-boom and 550mm Align CF blades. I removed the blades and did the vibration analysis and saved the plots (see attached). The X and Z snapshot images looked about the same, so I only show one. The Y was more dramatic so all three are shown along with some arrows pointing to items that I think are the motor, tail and head.

The Y axis (yy.png) seems like the problem. Is this showing me that I need to motor bearings? What should be my next change before re-running the test?

Thanks to anyone that sees and comments on this post.

Hello,

from the plots I can tell, that the only problem is motor.
It looks like a bent shaft or faulty bearing.

To be perfectly sure, move the motor from the main gear or unscrew the pinion and then spin up the motor.
If the spike will be still present, then it is for sure.

Other spikes are OK.

_________________
Spirit System developer

Another thing to watch for is the motor shaft spinning inside the inner race of a bearing. Fix by using some type of retaining compound (just a tiny bit) between the motor shaft and bearing.