MOTOR SPEED ERROR MAVIC MINI

[Zbip57]

Changed the blades twice and stills happened.

The problem will re-occur if you continue storing the Mini with the rear blades crossed.

I missed if you supplied the recipe for the CORRECT way to fold the rear props in to avoid distortion.

Here are four more images to illustrate the problem with the rear propeller blades.

The rear motors are mounted on an angle, canted outwards. Here you can see how the rear propeller blades point upward when turned out.


When the prop blades are turned inward (across the body of the Mini) you can see how fresh new (straight) blades extend away from the body of the Mini. If the blades from both sides are turned inwards they form an X with the tips crossing. The blades from one side will not fit under the blades from the other side unless one side or the other is bent to fold under the opposite blades. If your rear blades now slide easily together it can only mean they're already bent.


Obviously if you set it down on a tabletop with the blades positioned like this, the weight of the Mini will bend the blades. The Fly More case has a trough into which the rear blades can hang without the weight of the Mini resting on them. However, just forcing the blades into the required crossed position is already enough to bend the blades. So even if stored "properly" in the Fly More case, the rear blades are bending.


If you instead position the blades longitudinally down the sides of the Mini, the angle the motors are mounted at is level with the rear arms. You can set it down flat on a tabletop like this without bending the prop blades. However, they will not fit into the Fly More case, nor into the original plastic shipping tray of non-fly-more Minis, with the prop blades positioned like this.


I have been storing my Mini on a shelf with the arms open unfolded ever since replacing the propeller blades. For travelling, I ordered a new carry case which stores the prop blades positioned longitudinally, both front and rear blades down the sides of the Mini rather than laterally folded across the body.

Search for a "Sunnylife Mavic Mini Case". There are different types. This one allows the blades to be stored positioned longitudinally.

 

[SW_Drone_Guy]

Here's another solution. Take that guitar off the wall and put up the mavic mini. Now play that guitar!
Happy flying
Note: that orange ribbon is my reminder to remove the gimbal cover before flight.

 

[gymnast46]

After sending my Mini back to customer service for multiple Motor Speed Errors,reavis I now have a new problem. It was hovering just below 400' yesterday when I got a message saying "Propellers Rotating too Fast". The drone's performance wasn't impacted but I brought it down anyhow. Upon landing, the left rear props twitched constantly until I turned off the drone. This is really getting old.....

 

[sar104]

After sending my Mini back to customer service for multiple Motor Speed Errors,reavis I now have a new problem. It was hovering just below 400' yesterday when I got a message saying "Propellers Rotating too Fast". The drone's performance wasn't impacted but I brought it down anyhow. Upon landing, the left rear props twitched constantly until I turned off the drone. This is really getting old.....

It's not a new problem - it's the same problem. The props are not generating enough lift. There is nothing wrong with the aircraft.

 

[Oni]

Has anyone been able to figure out whether this new warning generated by the firmware update has an actual detrimental effect on the performance or health of the aircraft? I.e., does it matter or should we ignore it? If DJI hadn't told us, we'd never had known.

 

[FoxhallGH]

Has anyone been able to figure out whether this new warning generated by the firmware update has an actual detrimental effect on the performance or health of the aircraft? I.e., does it matter or should we ignore it? If DJI hadn't told us, we'd never had known.

Please have a read through this thread! The warning appears to come about due to the distortion of the prop blades when they are stowed across the body of the drone ... Please do those that have put so much effort into identifying this problem and suggesting a solution - the courtesy of reading their work before just posting a statement like this.
You can also get more info about this issue from this thread ... Mavic Mini uncommanded descent tests

 

[Oni]

Please have a read through this thread! The warning appears to come about due to the distortion of the prop blades when they are stowed across the body of the drone ... Please do those that have put so much effort into identifying this problem and suggesting a solution - the courtesy of reading their work before just posting a statement like this.
You can also get more info about this issue from this thread ... Mavic Mini uncommanded descent tests

I have read through the thread. I have gotten the message and seen the small distortion in my blades, presumably from storing in the FM case. I have changed them.

Let me re-phrase my question: DJI has created a warning message. Is this warning overly sensitive? Has it been confirmed that it is an actual functional issue, i.e.the extra motor speed due to the change in pitch of the blades is outside the acceptable boundaries of MM flight performance characteristics? An aircraft can have minor deviations in operating conditions & still be OK. I would be more concerned if the prop pitch was increased, since that produces greater thrust/lift and consequently more stress on the motor. Decreasing pitch simply requires greater RPM to produce same thrust/lift. Is that bad? I don't know. Maybe DJI some software engineer just created a warning flag that is inconsequential.
My experience has been that handling is no different after the message appears. Hope this question isn't too ignorant for you.

 

[FoxhallGH]

I have read through the thread. I have gotten the message and seen the small distortion in my blades, presumably from storing in the FM case. I have changed them.

Let me re-phrase my question: DJI has created a warning message. Is this warning overly sensitive? Has it been confirmed that it is an actual functional issue, i.e.the extra motor speed due to the change in pitch of the blades is outside the acceptable boundaries of MM flight performance characteristics? An aircraft can have minor deviations in operating conditions & still be OK. I would be more concerned if the prop pitch was increased, since that produces greater thrust/lift and consequently more stress on the motor. Decreasing pitch simply requires greater RPM to produce same thrust/lift. Is that bad? I don't know. Maybe DJI some software engineer just created a warning flag that is inconsequential.
My experience has been that handling is no different after the message appears. Hope this question isn't too ignorant for you.

Apologies - it did seem that your question in post #265 was ignoring the history of this thread - but the question above is very sensible.
The evidence suggests that within limits, the Mavic Mini will keep flying, as long as the rpm required for the manoeuvres that you put it through during flight, don't require more than max. rpm. However, there are numerous reports of 'uncommanded descents' where the MM will fall out of the sky in a situation where you need max power applied e.g. getting back from a down-wind situation. In other words, the rear motors are unable to get the Mini up on an angle to fly into the wind.
It also seems that this prop-storage problem has a cumulative effect i.e. the more it's done, the worse it gets ... The max. rpm warning will be produced early on, but before it becomes critical to the [normal] handling of the drone ...
The bottom line is that it's not 'bad' until you get to the point where you need the max thrust and the motors are unable to give it. Unfortunately, you won't know when that point is reached until it happens - and it is more than likely to be when you most need that max thrust to get your drone out of trouble!

 

[Zbip57]

Decreasing pitch simply requires greater RPM to produce same thrust/lift. Is that bad?

It is possible that the threshold at which the warning is triggered might be set too sensitive, as many people just ignore it and keep flying. Others have reported seeing the warning only once, and never again.

However, it is unwise to ignore repeated occurrences of the same warning.

The condition will certainly become bad if, in struggling to produce the required lift, the motor ever reaches its ultimate max rpm limit. The Mini's motor are not very powerful and can only produce so much rpm, and no more. There is another theory that an excessive rpm increase will further dynamically distort the shape of the propeller blades as the centrifugal forces become higher.

The evidence suggests that within limits, the Mavic Mini will keep flying, as long as the rpm required for the manoeuvres that you put it through during flight, don't require more than max. rpm. However, there are numerous reports of 'uncommanded descents' where the MM will fall out of the sky

For example...
Here's a video from Old Mr Kent (I love this guy) where his Mini experiences the Uncommanded Descent several times. He saw the Motor Speed Error already in a couple of previous videos, but decided it had something to do with overheating and bad motor bearings. On his earlier models he always used the lightest oil (a drop of gasoline) to lubricate motor bearings, so he tried that on his Mini. It didn't work.

He starts flying at 1:30 and immediately the warning pops up again. At 4:35 the Mini drops and hits the grass. Again at 5:25, 5:35, and 5:55. Also an earlier flight with propguards at 9:05.

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[manic]

Here's another solution. Take that guitar off the wall and put up the mavic mini. Now play that guitar!

Does that change the tone of the mini at all?

Looks like you need to Dust Your Broom.

But seriously, my experience with this issue...
Upgraded the firmware.
Got the error message.
Changed the props.
Paid attention to how I stored the mini in it's case.
Been steady as a rock.

Anyone know when/if MAS will release props for the mini?

 

[J Paul]

Here's another solution. Take that guitar off the wall and put up the mavic mini. Now play that guitar! View attachment 106464
Happy flying
Note: that orange ribbon is my reminder to remove the gimbal cover before flight.

That orange ribbon is a great idea!

 

[SW_Drone_Guy]

Does that change the tone of the mini at all?
But seriously, my experience with this issue... Upgraded the firmware. Got the error message. Changed the props. Paid attention to how I stored the mini in it's case. Been steady as a rock.

I went thru the same process you did, Manic, and the situation has not recurred.
I don't notice any difference in sound or handling, but no new messages...
Resolved?

That orange ribbon is a great idea!

That idea came from this forum. It's not my idea, but it works!
Happy flying all

 

[gymnast46]

It happened again tonight. Propeller speed error with the brand new blades. The left rear was indicated (again?). I changed the props and sent it aloft again only to get the same warning. This time I just let is hover at 50 feet altitiude (it was too windy higher up) and shot a video of the clouds. When the drone landed, the right rear props were twitching. This is the fifth time I've experienced this.

Unrelated: I took 13 minutes of footage and speeded it up to 19 seconds.

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[SW_Drone_Guy]

It happened again tonight. Propeller speed error with the brand new blades. This is the fifth time I've experienced this.

Unrelated: I took 13 minutes of footage and speeded it up to 19 seconds.

That must be extremely frustrating! I'm sorry you're going through it. For the record, are you putting your drone in the fly more case between flights? Or are you using that case at all? As you must be aware, that error mssg is being attributed to deformed propellers. The primary culprit for deformed propellers seems to be the case that comes with the fly more kit. Your experience and feedback will help others. Once again, I'm sorry you're going through it.
OH, BTW, GREAT TIMELAPSE!

 

[gymnast46]

I've been using the case and have been careful aligning the bottom props according to the instructions. I just wonder if these error messages are false readings. After the right rear props triggered the warning last evening I shut everything down. Today without swapping out the props it flew fine.

 

[Zbip57]

I've been using the case and have been careful aligning the bottom props according to the instructions.

Have you read these three posts above?

#247
#256
#261

Does any of that apply to you?

 

[gymnast46]

Have you read these three posts above?

#247
#256
#261

Does any of that apply to you?

Yep, I had read them. A lot of thought went into those posts.

I'm stubborn enough to think the original case should function without causing problems. I'm not convinced that sometimes the error messages aren't erroneous. As I mentioned above, the same props that gave an error message yesterday work fine today.

 

[Zbip57]

I'm stubborn enough to think the original case should function without causing problems.

Something seems to be causing problems for you.

I'm not convinced that sometimes the error messages aren't erroneous.

Doing a hover test and plotting the motor speeds will demonstrate whether or not the error messages are erroneous.

As I mentioned above, the same props that gave an error message yesterday work fine today.

Some people have reported that the props will eventually spring back to their original shape if left alone, i.e. not stored with their tips crossed.

 

[FoxhallGH]

Yep, I had read them. A lot of thought went into those posts.

I'm stubborn enough to think the original case should function without causing problems. I'm not convinced that sometimes the error messages aren't erroneous. As I mentioned above, the same props that gave an error message yesterday work fine today.

Not just thought - practical testing and observation too ...
Unfortunately, in this case your stubbornness is getting in the way of solving the problem ... Even to the extent that - as posted during this thread - it is actually impossible to fold and mesh the props as illustrated in the DJI drawing! (try it and look very carefully!!) DJI has made a mistake! - simple as ... if the rear motors were mounted 100% vertical then you might get away with DJI's fold-&-stow method. But - as shown in @Zbip57's great photographs in this thread, the rear motors are angled outward at about 5 degrees, and therefore, meshing the 4 props together across the body of the drone, WILL put pressure on the blades that will deform them by both bending them downwards, and flattening their pitch. This is made worse if the Mini is folded and stowed while hot after a flight, as the pressing of the blades against the hot fuselage will assist the deforming process.

 

[Scousemeister]

That must be extremely frustrating! I'm sorry you're going through it. For the record, are you putting your drone in the fly more case between flights? Or are you using that case at all? As you must be aware, that error mssg is being attributed to deformed propellers. The primary culprit for deformed propellers seems to be the case that comes with the fly more kit. Your experience and feedback will help others. Once again, I'm sorry you're going through it.
OH, BTW, GREAT TIMELAPSE!

I'm new to the Mini scene and have only a 20 minute test flight under my belt (on the latest firmware).

The way I view it (re bent props), if the Mini is sold in the fly more case, it should be considered a suitable candidate for the safe, repeated storage of the Mini. Should it fail to store it in such a manner that it's in a flight-worthy condition when using next, then the kit is not fit for purpose and any failure should be covered under warranty.

I'm on a low income and was kindly gifted my Mini kit so I'm a bit a**l in how I look after it (probably so I'll have it for some time to come and in a good condition). When I put mine away, I hold the props in place with the paper tab ties which held them in place in transit.

My line of thought in doing this is that if DJI presented the Mini in that manner, it must be the safest and least destructive manner in which to store it (re preventing prop distortion).

Should I witness any number of prop/motor related issues, it's my intention to have it resolved under warranty (after all, the warning message does suggest contacting support if the issue continues).