Aeronavics / Droidworx Skyjib 8 Motor Resonance

A

ATFlyer

Member
Hi

I have a SJ8 which flies really nicely but there is a strange vibration of the 4 motors that are on the booms where the landing gear is also supported (basically the front 2 motors & the rear 2).
Most of the time they run smoothly but every 2 or 3 seconds one of them will noticably shake, vibrating the boom. The motors are balanced, the APC 13x6.5 props are balanced and secure. None of the other motors do this so I think it is related to the landing gear fixings.

I'm guessing the fixings are either too tight or too loose and a standing wave is being created. The bolts aren't excessively tight, just enough to give the booms room to flex but not move in the plastic grips.

Has anybody else had this happen? If so how was it solved?
 

Droider

Droider

Drone Enthusiast
Never heard of this. I does sound like the props are out of balance though. Have yu solved it?

Dave
 

A

ATFlyer

Member
It's a weird one!
All props and motors are well balanced but there is still some shake. I loosened the Allen bolts that go through the polycarbonate brackets which seemed to reduce it. Vibration isn't showing up on the video though :tennis:

https://vimeo.com/55482136

Now it's working I'm reluctant to tinker!
 

Droider

Droider

Drone Enthusiast
Just a quick one.. the inner clamps are tight aren't they.. I am sure you thought of that..

Dave
 

A

ATFlyer

Member
I'll check those.
i never really know how tight "tight enough" is with these bolts, although i did mount a GoPro to the landing gear with just servo tape & then experimented with the bolt torque. It didn't really make much difference to the level of vibration.

Like I said in my original post since its only occurring on the motors that have the additional support of the gear rail brackets I wonder if its the extra bracing that is contributing to the resonance.

However it isn't affecting the flight character or the image quality so maybe I shouldn't worry! I only noticed it when I was spending ages hovering at head height just in front of me trying to tame my PH Skyline!!

Thanks for the ideas!

i think I did my BNUC-S with a mate of yours from Stockport. Your forum name cropped up in the bar. He does builds for Quadcopters?


Ade
 

Droider

Droider

Drone Enthusiast
That will be Paul 'eyeball'. His will be very red this morning as it was QC chrimbo party last night.. Unfortunately I could not make it as I got the bloody upchucking virus yesterday so been close to the bog for 24hrs!
 




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