Dangerous vibrations (For the Mavic) Help

[sar104]

Ok seems this thread is not over. I have establshed some issues which i believe contributes to this problem.
If i fly with prop guards and its windy it seems the propellers and wind combined is starting a motion in the prop guards making the craft start to vibrate. This in turn is messing up both the IMU and compass, so that when i remove the prop guards the vibration is still there. After re-calibrating the IMU and compass the craft stops vibrating. I have no clue why it does this but it does. My tip would be....dont be cheap like me. Buy real prop guards......or a bunch of propellers. pretty much the same thing

I hadn't realized that you had non-standard equipment on the aircraft. It's not surprising at all that it caused problems, but it is interesting that the resulting FC adjustments persisted between flights.

 

[Special Weapons Group]

I hadn't realized that you had non-standard equipment on the aircraft. It's not surprising at all that it caused problems, but it is interesting that the resulting FC adjustments persisted between flights.

Yes i thought that was very interesting too, and yes its crappy B accessories. Bought them as original but ....., well it was some kind of copys

 

[Qoncussion]

Ok seems this thread is not over. I have establshed some issues which i believe contributes to this problem.
If i fly with prop guards and its windy it seems the propellers and wind combined is starting a motion in the prop guards making the craft start to vibrate. This in turn is messing up both the IMU and compass, so that when i remove the prop guards the vibration is still there. After re-calibrating the IMU and compass the craft stops vibrating. I have no clue why it does this but it does. My tip would be....dont be cheap like me. Buy real prop guards......or a bunch of propellers. pretty much the same thing

This is probably "VRS" (Vortex Ring State). Prop guards are famous for causing it. They destabilize the air under the craft, causing severe wobble. There is no fix ~ at least not that I have seen. Lose the guards, and enjoy the bird

 

[Special Weapons Group]

This is probably "VRS" (Vortex Ring State). Prop guards are famous for causing it. They destabilize the air under the craft, causing severe wobble. There is no fix ~ at least not that I have seen. Lose the guards, and enjoy the bird

Already lost, will buy more props instead ;-)

 

[sar104]

This is probably "VRS" (Vortex Ring State). Prop guards are famous for causing it. They destabilize the air under the craft, causing severe wobble. There is no fix ~ at least not that I have seen. Lose the guards, and enjoy the bird

Maybe. Prop guards were infamous for making VRS worse on earlier designs like the P2, but VRS typically did not cause vibration, just loss of lift and lower frequency instability. And that would have been cured by removing them, and yet here apparently it persisted.

 

[Special Weapons Group]

Maybe. Prop guards were infamous for making VRS worse on earlier designs like the P2, but VRS typically did not cause vibration, just loss of lift and lower frequency instability. And that would have been cured by removing them, and yet here apparently it persisted.

Would be interesting to know why .?

 

[sar104]

Would be interesting to know why .?

I think that you probably correctly identified the cause of the vibration - the props were exciting some resonant mode in the prop guards that was feeding back and upsetting the IMU.

In terms of why it persisted, I suspect that the IMU is constantly tweaking parameters to achieve stable flight, and that those tweaks are not discarded at the end of each flight. Possibly, had you continued to fly it without the prop guards but with the vibration, then it would have fixed itself over time, but a calibration probably reset everything back to default and cured it that way.

 

[Qoncussion]

Maybe. Prop guards were infamous for making VRS worse on earlier designs like the P2, but VRS typically did not cause vibration, just loss of lift and lower frequency instability. And that would have been cured by removing them, and yet here apparently it persisted.

Agreed... I've not seen VRS on my Mavic, but had a VRS crash with my P2. When I cut this crash clip, I had attributed the crash to the carbon fiber props, but discovered later that it was VRS.

 

[sar104]

Agreed... I've not seen VRS on my Mavic, but had a VRS crash with my P2. When I cut this crash clip, I had attributed the crash to the carbon fiber props, but discovered later that it was VRS.

I had a couple of uncontrolled descents and hard landings, or really bounces, with my P2s, before I figured out to fly laterally out of the disturbed air, but no actual crashes. Exacerbated here by the elevation too.

 

[Endeavor]

My mavic did this first time I fired it up - I am using the new quiet props so I figured the imu needed a recal. For me that was the fix.

 

[Davester70]

Had exactly the same issue with exactly the same prop guards just yesterday, when doing some indoor filimg (it was in a very big space). I thought a large dustball (it was a very dusty location) disturbed by the downdraft had floated up and then been sucked in to one of the motors. Removed the prop guards just in case they were the cause, and that seems to resolve the issue straight away.

Prop guards were third party ones too, so I guess it's back to the DJI Store for authentic parts

 

[Special Weapons Group]

Seems this has to be adressed in some way or at last warn new Mavic pilots about this issue. Have anyone any experience of the cages? Why im asking is i get very close to people sometimes. We usually shoot many of our 2nd unit scenes with the Mavic since its so easy. Could We maybe use cages instead, whitout this issue?

 

[Special Weapons Group]

It really takes good night pictures tough

 

[Special Weapons Group]

Had exactly the same issue with exactly the same prop guards just yesterday, when doing some indoor filimg (it was in a very big space). I thought a large dustball (it was a very dusty location) disturbed by the downdraft had floated up and then been sucked in to one of the motors. Removed the prop guards just in case they were the cause, and that seems to resolve the issue straight away.

Prop guards were third party ones too, so I guess it's back to the DJI Store for authentic parts

Yep probably, i threw mine away as soon as this was suggested......and tried a last time. The pirate guards were crap was the final verdict [emoji1]

 

[Wipster]

what type of props are you using?

A lot of pilots say the less noisy props vibrate more but I hesitate to junk it was the prop protectors.

 

[Davester70]

Seems this has to be adressed in some way or at last warn new Mavic pilots about this issue. Have anyone any experience of the cages? Why im asking is i get very close to people sometimes. We usually shoot many of our 2nd unit scenes with the Mavic since its so easy. Could We maybe use cages instead, whitout this issue?

My personal view is that cages sound like the right solution for you. I've never used them, but I understand they will reduce flying time significantly per battery. Can anyone reading this thread give us some real world experience of using them?

 

[Davester70]

A lot of pilots say the less noisy props vibrate more but I hesitate to junk it was the prop protectors.

Worth exploring as a potential source - I was using the low noise props when I had my 'issues'...

 

[HighlandsVideo]

My MP vibrates exactly that way when I either, switch on the 'prop cage' option in the preference menu without installing the prop guards or, likewise, if I install the guards without turning on the option.

 

[jackmcelwain]

Ok seems this thread is not over. I have establshed some issues which i believe contributes to this problem.
If i fly with prop guards and its windy it seems the propellers and wind combined is starting a motion in the prop guards making the craft start to vibrate. This in turn is messing up both the IMU and compass, so that when i remove the prop guards the vibration is still there. After re-calibrating the IMU and compass the craft stops vibrating. I have no clue why it does this but it does. My tip would be....dont be cheap like me. Buy real prop guards......or a bunch of propellers. pretty much the same thing

I have this same exact thing happening on a Mavic Pro Platinum with (minus the IMU getting messed up). With prop guards on, the aircraft is very unstable when the wind blows. Have you ever found a permanent solution?