Hoverfly mysterious vibration

[octocine]

I have been struggling for about one month to get smooth video. I'm using the HFP with a Cinestar 8 and a Cinsestar two-axis gimbal as a single operator system with roll and tilt stabilization coming off the HoverflyPro board. The jiggle occurs in both auto-level and manual flight modes. The helicopter seems absolutely smooth in flight. When looking at the video the wiggle is primarily up and down and though post stabilization will take care of it, I would really like to eliminate this issue if possible because I think the movement makes the image softer. I've balanced the props, balanced the gimbal, balanced the helicopter as a whole and experimented with lower gain settings in the setup client, but all to no avail. I've suspended the helicopter in the garage, engaged the gimbal and wiggled the helicopter without flying and the problem is not there, which makes me think the mount is performing okay.

One thing I did learn is that the wobble is more pronounced in AH mode than when it is not engaged, but I have not been able to eliminate the jiggle. Is there anything else I can try or is this as good as it gets? Has anyone else been down this road and switched to the Radians and, if so, how do they compare?

 

[DucktileMedia]

Is it a high or low frequency vibe? You did some good tests and the fact that a flying mode would make more vibes than the other says it probably is a gain issue. But there is always more than meets the eye. Normally a decently balanced prop is enough to rid of vibes. One thing I would try first is using smaller props if you feel you have plenty of power. Unlike DJI, I think on the HFP you can tell what percentage throttle you are using by your stick position(throttle curve aside). If you are taking off at 30-40% throttle you are over propped. Spinning a smaller prop faster normally solves a lot of these vibe issues. Take a video hovering, then climb slowly and descend slowly. Watch where the vibes are more pronounced. Sometimes just the forward movement can make vibes from wind blowing over all that surface area of the heli and gimbal. I think the cinestar would be less prone to this compared to the Av200 though. as for gains, the HFP is so limited and easy to setup that I doubt it is gains. But it wouldnt hurt to try changing them a little, +/- 10pts.

 

[octocine]

Thanks for these suggestions. I would say it is a high frequency vibration and it is definitely up and down. I tried lowering the gain almost completely on the tilt axis of the camera mount, but it didn't improve things.That's an interesting idea with the props. I'm currently using the APC 14 X 4.7. I'm using a Spektrum DX8 and the throttle range is from -117 to 100. I can't remember why the bottom end is at minus 117, but as I recall there was a reason during the setup. My fully loaded CS8 hovers at a throttle setting of -6, which I assume is about 49%. Does this sound reasonable?

 

[Aerovideo]

I would also try flying with the servos on the gimbal unplugged. It might be the vibration dampening is too soft or too hard but if you take the servos out of the equation you might be able to see the vibration better.

I know when I unplugged my servos on an old gimbal I had, I discovered the vibrations were the servos. Probably not the issue in your case as you mentioned testing the gimbal alone in your garage but it still might help you track down the vibe.

 

[Webheadfred]

Hmmm. I had a vibration issue as well and I thought I had everything balanced perfectly. It was odd as when I first too off, there was no vibration. Af the flight progressed, it crept in and the a lot of vibration just before I had to land. I thought it had to be me. I changed to a smaller gimbal and there is less to none but that little gimbal doesn't perform as well as my RusticWave.

 

[Bartman]

octocine,

how old is the gimbal? the pots will wear out after a while and as that happens the video will begin to show vibrations. aerovideo suggested flying with the mount off or the servos unplugged, sometimes you'll get your best video this way! if the mount quiets way down with the servos unplugged then that tells you something about either the mechanicals of your mount or the state of your servos/pots.

bart

 

[DucktileMedia]

try 12"apc's. I still think 14's are too damn big for a 2814. But I am just assuming thats what you have for motors. Try em' all, gotta be one of the ideas listed here.

 

[Bartman]

i didn't like the 14" APC props on the 2814 motors either. regarding props, APC's on coaxial heli's never worked for me. i'm guessing the flimsy APC props don't like the rough ride the lowers have to endure and it comes out in the video. sometimes i'd get away with it, sometimes not.

otoh, worn out pots will always make the video jittery when everything else is working perfectly.

 

[octocine]

Thanks everyone for the advice! I'll get started on the suggestions you've given and let you know if I find the problem.

 

[Bartman]

how old is the gimbal you're using?

 

[octocine]

My gimbal is one year old.

 

[octocine]

One other thing I forgot to mention is that I tried adding more vibration o-rings on the mount, less vibration 0-rings and even no o-rings and the only thing I could conclude was that did not eliminate the vibration. The o-rings sure do help reduce vibration and it they seemed to work best when the o-rings seemed to just barely bend under the weight of the mount.

 

[xerofly]

One other thing I forgot to mention is that I tried adding more vibration o-rings on the mount, less vibration 0-rings and even no o-rings and the only thing I could conclude was that did not eliminate the vibration. The o-rings sure do help reduce vibration and it they seemed to work best when the o-rings seemed to just barely bend under the weight of the mount.

i suggest get hold of a mechanical brain...and he would resolve your issue in a minute....only way is to understand where is the mechanical problem which is causing vibrations...to resolve....

 

[Bartman]

My gimbal is one year old.

with a lot of use? first step should be to fly it with the servos unplugged. if it cleans up the vibrations then the pots probably need to be renewed.

bart

 

[octocine]

Thanks Bart. It has had a lot of use, so I might have just worn out the servos.

 

[Bartman]

Thanks Bart. It has had a lot of use, so I might have just worn out the servos.

are there external pots or are the servos using the pots they were made with? what kind of mount is it?

 

[octocine]

Okay, I am completely embarrassed to say that at last I discovered the problem. I loaned my Sony CX760 to a friend and he disabled the stabilization to shoot from a tripod. I feel so stupid for not thinking of that possibility. Apparently without the stabilization on the lens can jiggle. Thanks for all of the suggestions. I'm sure all of the other things I tried that you all suggested will help make smoother video as well.