MOTOR SPEED ERROR MAVIC MINI

[Rob2160]

A further update - on the third flight the problem reappeared - just hovering in P mode.

This time it was the front right motor (the one with prop originally on the rear left)

So I can confirm that for me the problem has followed the prop marked F3.

 

[Garbage]

A further update - on the third flight the problem reappeared - just hovering in P mode.

This time it was the front right motor (the one with prop originally on the rear left)

So I can confirm that for me the problem has followed the prop marked F3.

Do you suspect it's just a firmware bug?

 

[Rob2160]

Do you suspect it's just a firmware bug?

I think the fact that it followed the prop when I moved it means it is detecting something. That one is a little flatter than the rest - only by a small amount but definitely noticable.

When I get home I will try with the spare set of props.

 

[Klaaz]

I "FIX IT".

Guys I updated today my MM and I was surprised by the left rear engine problem after a few minutes of flight, I made several attempts and in all of them I had the same error however I made an interesting experiment, I exchanged the left rear propellers for the upper right ones (same type) and the error is gone.

One thing that is true is that those propellers (the ones from the original problem) actually look a little more bent than normal (I never crashed, but it has been saved for at least a month). Surely this new update detects the slightest change and for some other reason, the rear propellers are more susceptible than the front ones.

I have the error only in one flight, after then it disappears.
It is not sure in your case that it is the prop switch....

 

[Rob2160]

I have the error only in one flight, after then it disappears.
It is not sure in your case that it is the prop switch....

I feel pretty confident that it is the prop It was failing consistently on the left rear then it started to fail consistently on the front right when I put the suspect prop there.

Also I can see it is much flatter than the other three, it even has a tiny bit of negative pitch at the tips - the other three are all positive.

I replaced that prop with a new F2 (from the spare prop pack) and have flown it three times with no issue so far.

I think my prop got bent in the case as I have travelled with it quite a bit that way.

 

[Hughes820]

My back left motor is now loose all a sudden. Changed blades and turned on motors DRONE WAS LOAD AS HELL!. I was gonna take it out and test out the new props but I’m just gonna return it. I’ve had no warnings at all but since update drone hasn’t been stable at all. Update is causing the back left motor to overwork or something

 

[Nik-UAV_Pilot]

This sounds a bit like part 1 of the 'uncommanded descent' issues being discussed in other threads. It might be that the firmware upgrade is coincidental - but ... A couple of questions and suggestions:
1) Have you noticed any difference in the sound of the drone? i.e. does it sound like it's rpm is higher??
1a) If you have a second set of prop's and can change the REAR set of 4 blades only, does that change the flying sound to a lower pitch [rpm]?
2) Have you noticed any difference in the stability of the drone in the hover? Does it hover steady, or wobble about a bit??
3) Fold out the MM's arms and prop's, and looking horizontally at the prop blades - do the front set have a different shape to the back set?? i.e. do the props on the back look a bit 'flattened'?
4) Do you store the MM folded up in a Fly More case?
5) If the answer to 4) is Yes - do you make sure that the prop blades on the rear arms are lying east/west across the body of the drone, or do they angle back toward the rear of the drone when it is packed in the foam cut-out?

There have been reports of the MM being stowed in the Fly More case with the [rear] blades that end up on the under-side, angled back toward the rear of the drone. If that happens, the drone will sandwich the blades under itself. A foam block on the lid of the case puts added pressure through the Mavic down onto the blades sitting on top of another foam block under the MM. It seems that if this stowage is not done carefully, the blades on the rear arms, can get 'flattened' and lose some of their pitch. That then means they have to over-rev to get the same lifting ability. It's possible that the over-rev can also make the blades stall and lose all lift, making the MM descend.
Ideally, when in the Fly More case, the rear prop-set should sit free in an open space in front of the foam block that supports the belly of the Mavic.

I'm wondering if the motor speed warning is the first stage of this problem that has been seen by a few Mavic Mini owners.

There might be a propeller which is bent or damaged,
please observe the sound of the motor, probably the bent prop is making motor to spin faster or to put some extra efforts than other motors.
and change the respective propeller which is making motor to spin faster than other.

 

[FoxhallGH]

This photograph shows the DJI label, showing the way that the props should be orientated on the underside of the MM when its stowed in the Fly More case:



If the blades are not east-west, but are angled toward the rear of the drone, they will be 'sandwiched' between the body of the drone, and the supporting block of foam in the middle of the cut-out. If the drone has just been flown, its body will be hot, and the combination of the heat and compression will deform the rear prop blades. Note that there is also a block of foam in the case lid that applies compression down upon the MM, and would put further pressure on the blades.

 

[Arted]

I have exactly the same issue, just updated firmware and got the motor speed error. Diagnostic shows rear left motor/props to be the cause..... very odd that so many have the same fault. I did note that the update did stall and needed a retry, could this be the cause due to an erroneous update? I decided to revert back to previous version using DJI Assistant and flew the mini with no problems reported. However, the fault returned as soon as I installed the latest version, this time with DJI Assistant.....It certainly points to an issue with the latest firmware. Hopefully DJI can provide the answer.

the same thing for me , left rear arm , and when the drone was beeping the motor would make a noise a small movement left and right

 

[sar104]

the same thing for me , left rear arm , and when the drone was beeping the motor would make a noise a small movement left and right

Have you guys not actually been reading these threads? There is no mystery at all about this message.

 

[Alex Baxter]

Is it always the rear motors because they work harder in forward flight, (they have to tilt the drone). If anyone has this problem, would you try flying backwards to see if there is a front motor warning?

 

[sar104]

Is it always the rear motors because they work harder in forward flight, (they have to tilt the drone). If anyone has this problem, would you try flying backwards to see if there is a front motor warning?

Flying backwards doesn't result in such high speeds on the front motors. It's all covered in this thread:

Mavic Mini uncommanded descent tests

After a little experimentation I was able to replicate the uncommanded descent problem under 0400 firmware by loading the rear props for a few hours as might happen in the flymore case. The props did appear slightly flattened compared to the front props. The problem quickly manifested itself in...

mavicpilots.com

 

[Alex Baxter]

Flying backwards doesn't result in such high speeds on the front motors. It's all covered in this thread:

Mavic Mini uncommanded descent tests

After a little experimentation I was able to replicate the uncommanded descent problem under 0400 firmware by loading the rear props for a few hours as might happen in the flymore case. The props did appear slightly flattened compared to the front props. The problem quickly manifested itself in...

mavicpilots.com

Thanks for the link.

 

[Mattmoo]

Doh! @sar104. I store mine in the fly more combo case. Never bothered really how the props sat tbh. Until I joined this forum and followed sar104 and clearly his sheer amount of time spent figuring out what was going on. Now I do put my mini away more carefully. Props left to right as the picture shows and just place it in the case.

I havnt seen an error yet but I am on the look out n fly cautiously just incase. I want that drone back if it crashes!

 

[BaoRozzo]

Mine give the same error.
Probably put away incorrectly, too.
****...

 

[sar104]

Doh! @sar104. I store mine in the fly more combo case. Never bothered really how the props sat tbh. Until I joined this forum and followed sar104 and clearly his sheer amount of time spent figuring out what was going on. Now I do put my mini away more carefully. Props left to right as the picture shows and just place it in the case.

I havnt seen an error yet but I am on the look out n fly cautiously just incase. I want that drone back if it crashes!

Mine give the same error.
Probably put away incorrectly, too.
****...

While I got the Mini originally solely to explore this problem, my plan is to test stiffer props once they become available, and switch to those if they work, even if it takes the aircraft weight marginally over 250 g. I seriously doubt anyone is going to be quibbling over a couple of grams.

 

[rehkram]

I've had several flights since installing new Dji props. That coincided with the firmware update, and also the forum members' highlighting of how to correctly stow the props in the flymore case, thanks folks.

I haven't had an uncommanded descent since. Flying has been mostly in gusty conditions but nothing above 20 mph at altitude as indicated in the UAV Forecast app.

Just FYI.

Later... I forgot to mention that after the FW update I did get one early motor speed error during hover before landing. After landing saw the MM do its new trick shimmy with the back left. I did nothing to fix it since they were new blades all round. No further occurrences so far.

 

[Mattmoo]

If I get a warning which means change the props, then that's a good thing. If dji have seen a problem with props and then added something to firmware to warn us of this then that's a good move. Fair enough, maybe letting us know what the crack is would have been better . It's like the spanner warning light in a car.

Sometimes it goes bang, sometimes it goes chug. Some times it goes off the next time you get in.

 

[Thmoore]

Just to add my anecdotal evidence to the pile: pretty newly refreshed Mini, only a few short flights on it. I have and use the Fly More case and use this Sunnylife prop holder pretty religiously:

Upgraded, got the motor error on back left, replaced the prop. Immediately upon takeoff, got the motor error on back right; replaced the prop. No errors since.

 

[rehkram]

In my former career as software engineer we would have called this whole episode 'a bug in the documentation'.

We can reasonably assume Dji knew there was a problem, and knew how to fix it procedurally (why else would they put a sticker in the case, which I never looked at closely until it was spotlighted on this forum, I daresay I'm not the only one).

So why did Dji not just come clean and put more emphasis on the documentation and importance of their procedural fix, lame as their fix actually is? I think I just answered my own question there.