Paul Eastham
Well Known Member
Hi all,
Curious if anyone else has seen something like this: when my (9A) flaps start to go down, there's a quick "bang" or very brief grinding noise, I'm not sure which. No noise throughout the rest of the motion, and if I return them to up and go back down again, the noise won't repeat until several minutes elapse in the up position (either on the ground or in flight).
Video with sound: https://photos.app.goo.gl/RiQ4yuGHUN3fxTR17
I figure it must be one of two things:
1. gear between flap motor and actuator is slipping briefly
2. flap weldment is "sticking" / not rotating freely in the bushings
For #1, I just had the whole thing apart to replace my flap motor (it was intermittent due to brush issues). The problem existed before the motor change, and got slightly worse / louder after the change. I didn't see any signs of wear on the pinion gear or the "rack" that it interfaces with.
For #2, I have tried spraying some LPS-2 at the bushing / weldment interface, no change.
I also wasn't able to reproduce the problem when the motor was out of the airplane (i.e. moving the flaps by hand), making me more suspicious for #1.
Can anyone think of a #3?
Curious if anyone else has seen something like this: when my (9A) flaps start to go down, there's a quick "bang" or very brief grinding noise, I'm not sure which. No noise throughout the rest of the motion, and if I return them to up and go back down again, the noise won't repeat until several minutes elapse in the up position (either on the ground or in flight).
Video with sound: https://photos.app.goo.gl/RiQ4yuGHUN3fxTR17
I figure it must be one of two things:
1. gear between flap motor and actuator is slipping briefly
2. flap weldment is "sticking" / not rotating freely in the bushings
For #1, I just had the whole thing apart to replace my flap motor (it was intermittent due to brush issues). The problem existed before the motor change, and got slightly worse / louder after the change. I didn't see any signs of wear on the pinion gear or the "rack" that it interfaces with.
For #2, I have tried spraying some LPS-2 at the bushing / weldment interface, no change.
I also wasn't able to reproduce the problem when the motor was out of the airplane (i.e. moving the flaps by hand), making me more suspicious for #1.
Can anyone think of a #3?