Newbie Europe Posted at 5-16 08:52
And now the problem also occurs with brand new MM at the 1st flight. That would mean that DJI itself sends the new MM wrongly packed in the case to the customers. It would be very interesting to see who pays for all the replacement propellers. That's all very sad.

My advice is do not listen to that guy he’s trolling mini forum trying to create hysteria, he doesn’t own a mini and obviously has some gripe against dji.
You only need to either change prop or refresh FW. All Mini’s are flying extremely well with no problems caused by props apart from a warning that’s to sensitive and needs to be checked as dji have laid out. Not as is being touted here. Follow instructions as laid out by dji and no need to be led astray by trolls.


Check props for damage, if damage can be repaired repair, if no damage is visible your prop is fine.

Ottawa9876 Posted at 5-16 06:26
I had the issue appear on first flight after new software update.  Real left motor overspeed error.  Changed the props it went away but the props I changed were perfectly fine.  Emailed DJI.  Confirmed it is the software update that is causing the problem and the way you store can affect its props.  This is supper annoying.

Dear XYZ

Ignore what your being told by troll here, he doesn’t own a mini and information is incorrect. Follow instructions by dji and if there is no visible damage to your prop it’s perfectly fine.
Mavic mini have been flying without any problems since last FW and props are causing no problems to flight, unless of course they are visibly damaged.

m80116 Posted at 5-13 16:07
Scratches and scuffs play a marginal effect, blades flattened is a different matter. Even the slightest change in blade pitch can have good impact (and trigger errros).

For what I've seen MM props tend to be flattened (and now generate -motor speed error(s)-) at the tip, both because they're thinner and also because it's the part that gets caught in between the MM body and the bump at bottom of the Fly More case when incorrectly stored.

"Even the slightest change in blade pitch can have good impact (and trigger errros)."

Exactly.  Backed by science and real world.  Variable pitch blades on helicopters and lots of planes.  

With extreme example being reverse pitch on props used for air braking on C130J (or -ts 5:10).


In most of reported cases, the flattened blades, Bad (ccw?) blades, have sufficient pitch to still provide basic thrust at near max RPMs.  But not enough to fly safely, especially in strong winds or when doing sudden stops while flying forward.  

Cheers!

hallmark007 Posted at 5-16 16:15
Ignore what your being told by troll here, he doesn’t own a mini and information is incorrect. Follow instructions by dji and if there is no visible damage to your prop it’s perfectly fine.
Mavic mini have been flying without any problems since last FW and props are causing no problems to flight, unless of course they are visibly damaged.

Hi.  I am an experienced DJI Spark flyer which I sold to get the mini. So the issue happened to me and I google searched and landed here. So I'm first time poster.

That said, it is clear it is firmware update as per the email from DJI (software vs firmware means the same to me).

It shouldn't happen.  My props were perfectly fine,  They have the setting to sensitive  - that's it.

Love my mini except for this and fact its not as good in the wind as my spark.

Flew again today with the new props.  No issues but Ive been very careful with how I store it.

After all the bad experiences with the new Firmware I just wanted to say that I tried it yesterday the first time, because I was curious if I have to join the motor-error-club.
I didn't experience no errors at all.
I flew all 3 battery packs, tried slow stuff, tried full speed in Sports Mode. No problems.

The only thing that was strange is that I already got "bad WiFi connection" warnings after ~250m distance. I've never experienced that before.

I transport and store my Mini in the Flymore Case + one Plastic Cover over the top motors all the time. It was inside there now (except for doing the firmware update) for over a month now.

ABeardedItalian Posted at 5-12 15:12
Since you don't read my posts I won't bother to read yours.

It's pretty simple everyone, if you look at the official sticky and post #55 You will see a visually undamaged prop that is FLAT.

They say a picture paints a thousand words ! that speaks volumes!

HedgeTrimmer Posted at 5-16 15:50
Or Mavic Mini was packed correctly at factory; but sent out with set of Bad (CCW?) blades from a batch run (or several batch runs scattered over time) .  

If blades (CCW?) are Bad from factory, it would imply Mavic Mini pilots would have a difficult time visually determining whether a blade is Good or Bad; because factory trained QA inspectors were not detecting Bad blades.

i replaced all my props from day one after reading that the props had been packed too tightly by the company in charge of packing and shipping!

Just wanted to share my experience cause a lot of what I’ve read here helped me to fix mine.

After the new FW update I got the motor speed error on back right motor. Never had any issues with unplanned landings etc since Xmas 2019. Downgraded to the .400 software, no errors after that. Flight seemed visually ok.

Reinstalled new software, got the motor error on the rear left this time (have made no changes To props at this point).
Changed the rear left props for new ones and flew with no error again.
Of note the Right rear motor props have not been changed and not beeped in error again.
On closer inspection of the first left rear Props that have been discarded, they do look a bit flat in the shape compared to new ones. Before discarding them I tried them on the front right motor to see if the mini would recognise them to which it did and produced the error on the front right.
I believe that the fly more case is poorly designed and can flatten/reshape the rear propellers.
Cheers

Hello. Sharing my experience.

Purchased my Mavic Mini 3 days ago. Instantly updated to latest firmware via DJI Fly. Two days of flights all was OK. On the third day the "motor speed error" appeared. Rear left motor.
Refreshed firmware for drone and controller with DJI Assistant 2 and switched propellers between rear left and front right motors. Since then no error.

Bought a Mavic Mini 3 weeks back and have have been using the latest firmware since new with no issues until this morning.
Motor speed error popped up for the rear left prop.
Downgrading with my pc to 1.04 sorted the issue but as soon as I upgraded to 1.05 again the warning was back.
I changed the rear left props for a new set and the warning has gone. The ones I took off have no visible damage or deformation and the drone has never been crashed.
I'm assuming either the new firmware is faulty or the props have been slightly bent when  the drone has been stored in the case.

djiuser_4O91726DReXW Posted at 5-24 09:56
Bought a Mavic Mini 3 weeks back and have have been using the latest firmware since new with no issues until this morning.
Motor speed error popped up for the rear left prop.
Downgrading with my pc to 1.04 sorted the issue but as soon as I upgraded to 1.05 again the warning was back.

You can check for yourself if it's a FW issue, or a bad prop:

https://forum.dji.com/forum.php? ... D712%26typeid%3D712

Do the hover test we started using from post 185: indoor, bright light (for the Vision System to work well), auto-takeoff, 2-3 minutes hover without touching the controls, auto-land. Load the DAT file into CsvView, export the log to CSV, then calculate averages using the formula you will find on that thread.
With that specific test, good props average around 9400-9600 RPMs. We have seen props averaging in the 10200-10600 range without triggering any warning, so if you're below these numbers you should be good. If you're above that, your call.... I replaced props on my Left Rear motor because it was spinning higher than the others... and new props made a big difference. I never got a single warning and my MM has always worked well, yet the data showed that those props were not optimal, so I replaced them.

Just received this error on my first flight out of the box. Drone was never even used. Hoping it’s an issue with the firmware and not the brand new drone. As soon as it went into the air I got the message.

Jason Sirignano Posted at 5-25 12:00
Just received this error on my first flight out of the box. Drone was never even used. Hoping it’s an issue with the firmware and not the brand new drone. As soon as it went into the air I got the message.

Don't hope or guess, check your motor speeds as explained 2 posts above this one. If you don't want to install CsvView, do the hover test and post the corresponding DAT, happy to look at it.

I think it’s pretty clear, the prop testing has proven to be a folly, and continuing to ask users to test hover put up logs when nothing has been proved one way or another. But there is plenty of proof that prop warning is neither consistent or correct. So asking others to carry out bogus tests that give no answers is futile . There are many good workable workarounds to this faulty prop warning for those who have found that props are completely new and visibly undamaged.

One point has been completely lost in all of this and completely ignored by the prop testers, and that is since Mavic Mini last FW update the craft has been flying much better and this has been acknowledged by many members , with almost no drop outs no uncontrolled descents and many other problems seemingly ironed out. I think it’s also clear that props or props alone were not the cause of uncontrolled descents, no matter how hard a few tried to convince many they were.

Dji have left instructions on sticky on the top of forum. If you find that you have a perfectly good prop but still get warning, either update FW on dji assistant or change prop both of these solutions are proven to work and no problems have resulted in carrying these out.

hallmark007 Posted at 5-26 08:56
I think it’s pretty clear, the prop testing has proven to be a folly, and continuing to ask users to test hover put up logs when nothing has been proved one way or another. But there is plenty of proof that prop warning is neither consistent or correct. So asking others to carry out bogus tests that give no answers is futile . There are many good workable workarounds to this faulty prop warning for those who have found that props are completely new and visibly undamaged.

One point has been completely lost in all of this and completely ignored by the prop testers, and that is since Mavic Mini last FW update the craft has been flying much better and this has been acknowledged by many members , with almost no drop outs no uncontrolled descents and many other problems seemingly ironed out. I think it’s also clear that props or props alone were not the cause of uncontrolled descents, no matter how hard a few tried to convince many they were.

If you find that you have a perfectly good prop but still get warning, either update FW on dji assistant or change prop both of these solutions are proven to work and no problems have resulted in carrying these out.

I applaud your sound logic: if you have a perfectly good prop [...] change prop.

For those who like to take a slightly more scientific approach, checking RPM speeds is the way to go. The hover test is simple, takes 5 minutes, and gives results that are easy to read and compare, and far more accurate than a simple visual inspection. Moreover, it allows people to see for themselves.

120ccpm Posted at 5-26 10:58
If you find that you have a perfectly good prop but still get warning, either update FW on dji assistant or change prop both of these solutions are proven to work and no problems have resulted in carrying these out.

I applaud your sound logic: if you have a perfectly good prop [...] change prop.

There you go again, I think if you read many posts above you will see many who have had perfectly good prop but got warning, similar to Mavic Air1 perfectly good compass but get warning to calibrate, it’s quite common with these drones to get false warnings.

The problem with telling others to do hover test is to then try convince them they need to change a perfectly good prop. And yes I know I have told them to change a good prop, but because they are anxious to get flying and it’s a simple fix to get going. Your test hasn’t helped anyone, improvement in FW is what has made the difference to this drone, but ignorance on your part trying  desperately to convince others their props are invisibly damaged, this test requires testing indoors not outdoors flying normally, and if you read the answers given they are so diverse and explain very little, the test hasn’t shown to improve any flying, but if one was to read through the mire of different opinions, confusion is all new users would be met with.
I find it ironic that the prop crew still refuse to admit that improvements other than props are resulting in a much better flying experience for all mini users, it’s like something’s stuck in the craw of your throat “desperation” . Just accept it props didn’t cause uncontrolled descents and trying to convince others particularly new users that somehow invisibly damaged props are going to cause their drones to fall out of the sky is ridiculous and totally unfounded, and it’s clear from djis message that if props are not visibly damaged they are not damaged. Get over it, move on to your next folly....

Jason Sirignano Posted at 5-25 12:00
Just received this error on my first flight out of the box. Drone was never even used. Hoping it’s an issue with the firmware and not the brand new drone. As soon as it went into the air I got the message.

Suggest following 120ccpm's advice.

Keeping in mind, your kit replacement Prop could be bad from factory too.   Some MM owners have been able to swap left rear prop for right front pop for testing or similar if FW flags different motor than left rear.

As unlikely as it seems to get both a bad Prop on MM and bad Prop as a spare in kit, unforuntaely stuff like that does happen.   Been there done that with other DJI products.

hallmark007 Posted at 5-26 11:25
There you go again, I think if you read many posts above you will see many who have had perfectly good prop but got warning, similar to Mavic Air1 perfectly good compass but get warning to calibrate, it’s quite common with these drones to get false warnings.

The problem with telling others to do hover test is to then try convince them they need to change a perfectly good prop. And yes I know I have told them to change a good prop, but because they are anxious to get flying and it’s a simple fix to get going. Your test hasn’t helped anyone, improvement in FW is what has made the difference to this drone, but ignorance on your part trying  desperately to convince others their props are invisibly damaged, this test requires testing indoors not outdoors flying normally, and if you read the answers given they are so diverse and explain very little, the test hasn’t shown to improve any flying, but if one was to read through the mire of different opinions, confusion is all new users would be met with.

You don't see value in analyzing motor speeds? Don't do it. I am convinced that the hover test is valid and provides reliable data points for people to read, instead of unfounded opinions. You're entitled to disagree, but I will most definitely continue to recommend it.

Acknowledging it only reasonable to update MM to .500 FW, making sure FW was successfully installed, and swap out props flagged bad by FW first time around - continuing to swap props which are flagged bad or MM continuing to suffer from un-commanded descents; risks loss of Mavic Mini or a possible damaging crash of MM.  


As suggested in post #6 of this recent thread "Mavic Mini dropped down all of a sudden"; pilot is likely to be better served by opening a ticket with DJI.  At least going on record as having bad props / un-commanded descents.

Well the only way to be sure is to simply look at motor speeds before and after error solving (by changing props, or refreshing FW, etc) and compare. If it is purely a bug where the FW throws the error randomly then the motor speeds should not be significantly different. If they are different - and there have been several reports showing this factually - then that means that the FW 0500 picks up something real (which is a good thing). Then the debate is about the sensitivity of that error trigger; considering this error message is new it may need further testing and tuning. Nobody said that there was no improvement on the uncommanded descent and stability with the new FW; the question is different here, it is about the pertinence of this new error message.

Dont change props, it depends how many batteries you have. Each battery should be updated via Dji assistant, and will be ok, if proops look good

Ukash Posted at 5-27 04:30
Dont change props, it depends how many batteries you have. Each battery should be updated via Dji assistant, and will be ok, if proops look good

What's the connection about batteries and the Motor Speed Error that is being discussed on this thread???

I received the Motor Speed warning for the left-rear motor on this flight.  This is a plot of the individual motor speeds.  I was conducting Return-to-Home tests.  The left side of the plot shows the Mini taking off for just a moment, but someone came to talk to me so I had to stop the recording and land for a moment.  At about the 180 second mark I took off again.  The flat lines in the plot are where I shut the controller off to force a loss-of-signal to trigger a RTH response.  The app records no telemetry data during the time the signal is lost.  I turned the controller back on and cancelled RTH.  At the right end of the graph I again turned the controller off and allowed the Mini to return Home and land.  The plot lines drop to zero when I turned the controller back on after the motors had already stopped.

None of that is relevant to this thread discussion, I just wanted to explain what was going on during this flight.  What is relevant though is that here we have actual motor speed data, not just someone's misguided opinions or mere conjecture.  The blue line is the left-rear motor speed.  Yellow is right-rear.  Red is right-front.  Green left-front.

The lines jump up and down because I was flying the Mini back and forth, outdoors, on a windy day.  All you need to see in this graph is that the left-rear (blue) motor speed is significantly and consistently higher than any of the other motors, reaching a peak speed of nearly 16,000 rpm at one point.  The right-rear (yellow) is consistently the second highest speed.

This is the flight that first triggered the Motor Speed warning for me.

I susbequently replaced the left-rear propeller blades, as identified by the beeping ESC after landing, and as instructed by the warning message.  I did NOT reinstall the firmware to see if that makes the warning go away.  I did NOT downgrade to a previous firmware version to avoid ever seeing the message again.  I did inspect the prop blades.  There were NO obvious knicks, cracks, or blemishes to be seen.  Nonetheless, I did NOT ignore the warning.  I replaced the blades as instructed.   There's more to the story yet to follow...

120ccpm Posted at 5-26 14:21
You don't see value in analyzing motor speeds? Don't do it. I am convinced that the hover test is valid and provides reliable data points for people to read, instead of unfounded opinions. You're entitled to disagree, but I will most definitely continue to recommend it.

I am also convinced the hover test is valid.  Do it indoors so there's no chance of wind interfering with the test results.  Make sure it's a well-lighted space so that the vision sensors have something to lock on to.  Press auto-takeoff, allow the Mini to hover for a couple of minutes, then press auto-land, all without touching the control sticks.

Here's my first plot of Motor Speeds after replacing the left-rear prop blades with a fresh pair that have never before come out of their box.

Note there are still fluctuations in the lines.  Even though it is just hovering indoors, the prop downwash is causing enough turbulence in the room that the flight controller still needs to make small corrections to hold position.

More importantly, note how with fresh props the left-rear (blue line) motor speed is now no longer the fastest of the bunch.  Now the right-rear (yellow) is the fastest.

Even though I received no further warnings, and even though the other motor speeds don't look all that bad, out of curiosity I went ahead and replaced the right-rear (yellow) prop blades.

Note how the yellow, red, and blue lines are now relatively the same, while the left-front (green) is now consistently running at the fastest speed.

So I went ahead and replaced the left-front (green) prop blades as well.  Now all the motors, while in hover, are running at relatively the same speeds, certainly nothing over 11,000 rpm as seen in the first hover test.  Only the right-front blades are still the original set.



The reason to do this as an indoor hover test is that the conditions are more likely to be repeatable, as opposed to flying around outside on a windy day.  I may, or may not, ever again have seen a 16,000 rpm Motor Speed warning when flying normally outdoors.  That doesn't mean the "bad" prop has somehow magically cured itself.  It just means the threshold wasn't tripped by those particular flying conditions enough to trigger the warning.


You can choose to believe that reinstalling the firmware "cures" the issue.  Or you can choose to believe that, if you cannot see anything wrong with the props, it's safe to ignore the warning advising you to replace the prop blades, and just go on flying instead.

These graphs clearly demonstrate that there is a difference in performance between the old props versus the new props.

The question remains, why is there this obvious difference in performance between old props versus fresh props?  And why are people getting the Motor Speed warning even with brand new Mavic Minis straight out of the box on their first flight?

This diagram shows how the front and rear motors are mounted on  different angles.   I don't know the actual precise angle, these are  just estimates, but the rear motors are noticeably canted outwards,  while the front motors are canted rearward.

With the arms folded back, this is how the new left-rear prop blades look compared to the original right-rear blades.  Note that the tips of the new blades stand significantly higher than the old ones.  With the previous original blades, the left and right side nested easily over/under each other.

The rear motors are noticeably canted outwards.  Here's just the new left-rear blades.  Note how they angle up to point over top of the right motors.

Now here are the new right-rear blades.  Compare those to the old ones shown a couple of posts previously.  The tips of these new blades point up and past the top of the left motor.

You can see that the fresh blades now cross each other, rather than slide easily under/over each other.  Because the tips of the new blades sit noticeably higher on each side, due to the motors being canted outboard, trying to fold the rear blades together for storage requires forcing one side or the other to bend under the opposite side to force them to mesh.

Even when stored "properly" in the Fly More case, ensuring the weight of the Mini isn't sitting on the rear props, the fact that the new blades are forced to bend in order to get them to mesh is what causes them to eventually deform.  The deformed props are less effective at generating lift, so the motors have to spin faster to compensate.  At a certain threshold conditions, this will eventually trigger a Motor Speed warning and recommendation to change the prop blades.  EVEN IF YOU CANNOT VISIBLY SEE DAMAGE TO THE BLADES.

Do the hover test and check the motor speeds.  If you don't know how to run the analysis software, do the hover test for a couple of minutes and post the DAT file for someone else to analyze.

So why are we seeing these warnings on brand new Minis straight out of the box?  They're shipped to you stored in a box with the arms folded and props nested.  Who knows how long they've been in that box before your first flight.

So why are we seeing these Motor Speed warnings predominantly on the rear motors, and only rarely on the front motors?

With the arms folded, the front motors are very nearly level with each other, maybe even canted slightly inwards.

Here are the new front-left props.  Note the level of the tips of the props relative to the right motor.

And here are the right-front blades.  Note: These are still the original blades.  I've been flying on them since December and the Mini has always been stored with the arms and props properly folded in the Fly More case.  See how the tips of these blades still sit at exactly the same height as the newly replaced left-front blades.

Because they sit at the same level with each other, the front prop blades can be folded together to nest over/under each with minimal bending stress imposed on the blades.

I suspect this is why the front blades show less tendency to deform, compared to the rear blades.

Do yourself a favour.  Don't listen to people's opinions based solely on something their uncle's, mother's, hairdresser's son reported about how the motor speed warning goes away forever if you reinstall the firmware ten times, or you downgrade to a previous version, or you just look at the props and can't see anything wrong with them.

Do the simple hover test and check your motor speeds.

It's a clear and undeniable demonstration comparing the relative health of your propeller blades.  If you prefer, you can still choose to ignore that evidence.  But at least your decision is based on a repeatable, verifiable, and easily documented test, rather than based on the unreliable opinions of others.

Some people insist the earth is flat, the moon landings never happened, aliens crashed their UFO in Roswell, and Elvis is still alive.  They'll never believe anything anyone says in trying to convince them they're wrong.  In comparison to that, Mavic Mini motor speeds are dead easy to confirm with a simple hover test.

Zbip57 Posted at 5-27 11:35
So I went ahead and replaced the left-front (green) prop blades as well.  Now all the motors, while in hover, are running at relatively the same speeds, certainly nothing over 11,000 rpm as seen in the first hover test.  Only the right-front blades are still the original set.

Well done!  Very informative!   

Zbip57 Posted at 5-27 12:02
You can see that the fresh blades now cross each other, rather than slide easily under/over each other.  Because the tips of the new blades sit noticeably higher on each side, due to the motors being canted outboard, trying to fold the rear blades together for storage requires forcing one side or the other to bend under the opposite side to force them to mesh.

Even when stored "properly" in the Fly More case, ensuring the weight of the Mini isn't sitting on the rear props, the fact that the new blades are forced to bend in order to get them to mesh is what causes them to eventually deform.  The deformed props are less effective at generating lift, so the motors have to spin faster to compensate.  At a certain threshold conditions, this will eventually trigger a Motor Speed warning and recommendation to change the prop blades.  EVEN IF YOU CANNOT VISIBLY SEE DAMAGE TO THE BLADES.

Zbip57,

Do you mean DJI's suggested way for folding propellers is wrong ?

Please, give us any advice about the right way for folding propellers and storing our minis.

R.

I have the same problems since update

Zbpi57: this is a very impressive research and demonstration, thank you. As shown by you and some other users, there is now clear evidence that changing props for new usually reduces the rpm therefore showing some props do not have the same lifting quality. What is worrying is the reporting of the error message in brand new MMs (was not the case for me), but this could be due to a combination of bad prop production and an overly sensitive error throwing algorithm.

Now while I understand the importance of not squeezing the props under the body of the MM in the Fly More case, I find it incredible that even nesting the props as recommended by DJI is sufficient to reduce their quality. My new MM came with LBack props which look slightly flatter than the RFront ones (which should be identical, see pictures in my previous posts on this thread) but I never have experienced any error. I always store in the case the way DJI shows on the picture (albeit the picture itself is somehow wrong when it comes to props on the same motor). What I noticed however, after a dozen of flights, is that doing the hovering test shows slightly elevated mean rpm values for all motors now compared to the very first hovering test flight, by around 5% (e.g. going up from 8700 rpm to 9200 rpm). I will monitor if this evolves over time.

Another point: this is about the reporting that refreshing the FW fixes the error. It may be true but an artifact. It is possible that by reflashing the FW erases all historical rpm data files from the MM on which the flight controller depends to throw the error message (since we do not know how it works). So what seems like a fix may only be a temporary one.