Sudden increase in vibration

ArduCopter Copter 4.6
1

Hi

I was earlier using some 9450 DJI props which had gotten slightly bent due to a small crash (little prop crash into wall) so I bought new props and replaced all 4 with new ones.

However, I flew for some more time after the crash and vibes were slightly higher (I deleted the log, it was long back, from the pixhawk too), around 1 m/s2 more on all axises. but, after prop replacement, the vibration increased as follows:
X: 5 to 5.5 ( not much)
Y: 8 to 15
Z: 10 to 30 (maybe ±2)

this much vibration is dangerous and also reduced performance in loiter and other flight modes

one thing that I noticed was that the old props had plastic hubs (the part that screws onto the motor) and new ones have metallic hubs.

The propeller are self locking and the motor is compaitable and mounting, setup is fully correct.

What can be the cause of this?
I have used rubber dampener on motor base (motor-arm) and also the Pixhawk is mounted on foam tape.

2

Without a .bin log file and vehicle photos we can only speculate:

My speculation is that a motor got damaged in the crash, or had developed mechanical issues.

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3

The motors do not show any signs of damage and the crash was very minimal and damage to motors is super unlikely, and also the vibration with old props are only slighty higher, which is because one prop got bent near the end.

As I said, the old log has been deleted but I will attach the new log soon

4

I’d say to check the frame if any arms got loose.

Are you also using ESC telemetry for the notch filter? You can use the filter review webtool to analyze of there are any changes

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5

Frame screws are fully tight, and loctite blue has also been applied.

Esc telemetry is not possible because I am using vintage blheli escs that support just oneshot125

I also did some searching, and gemini suggests that plastic hubs deform/bend slightly and absorb vibration but metallic hubs pass through all the vibration

Th filter review suggrsts the same, around 80hz as previously configured

6

Just check if the new hubs cause the props to be out of horizontal alignment especially if the bore of the new ones are bigger than the old with a loose fit on the motor shaft. This can cause vibrations.

7

The props are same size
But, since these props are pretty cheap (3 dollars approx.) I suspect that the metallic part might not have been inserted properly.
I tested two of the old props which were not bent and I did spinnup of motor and mission planner didn’t say much vibration

It is now having some clipping around 20 at end of flight, with old props clipping was 0 in multiple tested flights.

8

as @amilcarlucas said .bin with pictures are next steps.

9

Why not try the old hubs with the new props? Only works if the prop bores are of the same size though.

10

Actually I just tried some new props and it has no vibration anymore
Maybe that set had gotten damaged in shipping