X7 Has Developed Severe Jello Issue

[ryevisuals]

I've been flying the Inspire 2 / X7 combo since release. It's been nothing short of fantastic. Recently, however, I have been struggling with severe jello during video. Increasing shutter speed makes it more apparent, while dropping shutter speeds just creates a blurry image. I have replaced the three rubber isolation bits that connect the gimbal to the aircraft - to no effect. Very frustrated as this expensive setup has been rendered essentially useless as of late. Here is an example of the issue:

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Any input would be greatly appreciated.

 

[ventek]

Check your drone for unbalance props or something loose jello is from vibration good luck. Tom

 

[ed.matthews4]

I was thinking Props right away. Try a new set? cheap enough test.

 

[S White]

The rubber balls can be a problem. I typically have issues when flying in cold weather and they get stiff and do not work well. The props could be an issue. One thing I also tweaked on my I2 is the prop seating. There is often a bit of movement / rocking in the props. So I took some short pieces of electrician tape and made little spacers. Makes the props a bit harder to mount, but they are now rock solid. And that nasty sound when finger turning them is also gone. The props are critical to take care of.

 

[AntDX316]

Props need to be changed or something else is wrong w/ the drone. Maybe the IMU gummies need replacing.

 

[mmarian]

Props need to be changed or something else is wrong w/ the drone. Maybe the IMU gummies need replacing.

Newly developed jello is sign of excessive vibration in the frame. New props and if possible the shims (from Atellani) should fix it. Also worth checking are the motor bearings. Turn them with hand, you should feel very slight resistance as the rotor jumps between magnets of the stator but other than that they should spin smoothly and without any noise.

 

[niki]

As you where using this setup from a long time probably a dumb question but what shutter speed and what fps you're shooting at?

From all stuff that was already mentioned - trying with new props and checking the motor's shafts is essential. But I'll also check do the motors are staying firm in their mounts as well if there is some play in the arms of the drone. Does the jello appears when landing gear is down, also does the frame/arms look symetric on both sides with landing gear down and up?

 

[ventek]

I've have not heard any body say to put the props on a balancer. It fast and way more cost effective than putting on a new set of props. Tom

 

[mmarian]

I've have not heard any body say to put the props on a balancer. It fast and way more cost effective than putting on a new set of props. Tom

Easier said than done.
It is possible though. Here is how. New Inspire2 comes with a set of spare prop mounts. The part which is screwed to the motor has a 5mm diameter hole. When a bit of 3M celo tape is put over the square block which goes into the square opening of the prop, it is a solid snug fit and now we have a normal prop with 5mm hole. I have 5mm steel rod, coincidentally a main prop shaft from T-Rex450 helicopter, perfectly straight about 4" long. With that I can now mount the prop on that shaft into Dubro prop balancer. The rest ist just following the proper prop balancing instructions. There are plenty of "how-to" on YT.
Having said all that, the I2 props from my experience are pretty well balanced out of the box. And in case of the OP if his I2 has "developed" jello the props do not go out of balance just all of sudden, unless chipped or damaged by hitting something. On the other hand unbalanced (damaged) props can cause all sort of issues when the vibs are transfered to main or gimbal IMU. From strange flight behaviour to jello. So checking the props for minor cracks or chips is important after each flight.

 

[ryevisuals]

Hello everyone,

I really appreciate all of the responses. Here is what I've tried so far:

• new props
• checked for loose motor mounts, bearings, etc
• Added the Atellani frame stiffening kit and prop shims
• tried different lenses/counterweights
• swapped out the three damper/isolator balls

The aircraft seems to be in perfect order, but the vibration persists. Today I messed around with running the motors w/o props while the aircraft sat on my countertop, just to see how the gimbal behaved. I think I have narrowed down the issue - I have made another video to show you:

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I know you can't see it in the video but the situation is this: when the motors are spinning the gimbal starts to vibrate heavily. It feels like this vibration is coming from the yaw axis on the gimbal. It feels like the gimbal motor for this axis is rapidly fighting itself to stay centered in some kind of a feedback loop, rather than settling out into position smoothly. However, this only occurs when the motors are spinning (with or without props, doesn't matter).

 

[mmarian]

Hello everyone,

I really appreciate all of the responses. Here is what I've tried so far:

• new props
• checked for loose motor mounts, bearings, etc
• Added the Atellani frame stiffening kit and prop shims
• tried different lenses/counterweights
• swapped out the three damper/isolator balls

The aircraft seems to be in perfect order, but the vibration persists. Today I messed around with running the motors w/o props while the aircraft sat on my countertop, just to see how the gimbal behaved. I think I have narrowed down the issue - I have made another video to show you:

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Basically, when the motors are spinning the gimbal starts to vibrate heavily. It feels like this vibration is coming from the yaw axis on the gimbal. It feels like the gimbal motor for this axis is rapidly fighting itself to stay centered in some kind of a feedback loop, rather than settling out into position smoothly.

Silly question.Have you performed the gimbal calibration? I'd also try to do it with the motors runing. Not sure if it possible though.

 

[ryevisuals]

Silly question.Have you performed the gimbal calibration? I'd also try to do it with the motors runing. Not sure if it possible though.

Yep, I have tried gimbal calibration with multiple lenses. You cannot calibrate the gimbal with the motors running.

 

[mmarian]

Yep, I have tried gimbal calibration with multiple lenses. You cannot calibrate the gimbal with the motors running.

Hmmm. You have exhausted almost all options. Can you feel any play on your gimbal? I have a bit of play on roll motor, yaw and pitch no play at all.

 

[mmarian]

Hmmm. You have exhausted almost all options. Can you feel any play on your gimbal? I have a bit of play on roll motor, yaw and pitch no play at all.

I would try one more thing. Remove the gimbal and start the motors without props as you did before and see if vibrations can be felt on the gimbal plate. Without props the frame should be almost vibs free and you certainly should not be able to feel any vibs on the antivib plate.

 

[niki]

Use app for measuring vibrations, there are many for android and ios. Tape the phone to every single arm, close to the motor and compare the results. That way you will find the most vibrating motor and if it vibrates much more than the others then that's the place.

 

[ventek]

Did you check all the cable connection going to the camera ?

 

[ryevisuals]

Just wanted to follow up on this thread - the issue is now fixed. I sent the X7 in to DJI for repair, with the following description:

"Gimbal vibrates heavily in yaw axis when motors on aircraft are running. This causes a "jello" effect in video (very noticeable with DL 50mm lens) and renders it unusable."

DJI decided to replace the yaw axis arm assembly on the gimbal. Total cost of repair was $285 and the process took just under two weeks from shipping it out to receiving it back. After running a series of tests that previously triggered the vibration issue, it seems to no longer occur. So glad to have my X7 back in action.

 

[The Editor]

Closed