JB 9 Posted at 4-27 13:53
Wow! I've been reading the forums off and on for a couple of years before pulling the trigger. (a little over cautious?)  Anyway in my travels I've learned more than I can remember. (let's get to the point) As we all know or should know no one ingredient makes a stew. One certain system failure can bring down the biggest Bld, airplane, etc. The .Dat charts blew me away. Good job Gramjohnson, you've shed new light on a forum that was getting no where.

Does anyone own a boat or an airplane? The pitch of the prop is everything. Older two cycle motors liked 6200 rpm (peak horsepower that didn't destroy the motor) A lower pitch the boat accelerates quicker, air planes climb faster but neither goes its potential for speed. Now electric motors are different from gas. There is a pitch that works best for longevity (flying time) If I wouldn't have seen the second Dat. chart I would have thought that the left rear corner was heavy and the prop had to spin faster to hold up the corner. If you put the old and new props under a microscope you probably can't see a difference. Changing the props definitely brought the RPMs in line don't you think.

In helos, we had a horrible situation which we always tried to avoid...it's called "Settling with Power"...meaning...you descend or are caught in your vortex...thus creating a void in lift and a fatal descent.

You only have to understand that everything on this drone was made to keep weight down under 249g. The issue with the props has to do with how thin and lightweight they are. It means they are easy to warp or damage even in storage. I see some prop holders that hold the props on an angle which is ridiculous. The drone props have to be laid horizontally without any pressure on them the way they came when you bought the drone.

deathsquad Posted at 4-27 14:34
You only have to understand that everything on this drone was made to keep weight down under 249g. The issue with the props has to do with how thin and lightweight they are. It means they are easy to warp or damage even in storage. I see some prop holders that hold the props on an angle which is ridiculous. The drone props have to be laid horizontally without any pressure on them the way they came when you bought the drone.

How do you explain those using combo case having no problems, in fact I’d safely say 95% are having no problems with props, mine are on now 5 months they’ve been in combo case since and have had no special treatment but work perfectly, is it props or not props or a combination ?

JB 9 Posted at 4-27 13:53
Wow! I've been reading the forums off and on for a couple of years before pulling the trigger. (a little over cautious?)  Anyway in my travels I've learned more than I can remember. (let's get to the point) As we all know or should know no one ingredient makes a stew. One certain system failure can bring down the biggest Bld, airplane, etc. The .Dat charts blew me away. Good job Gramjohnson, you've shed new light on a forum that was getting no where.

Does anyone own a boat or an airplane? The pitch of the prop is everything. Older two cycle motors liked 6200 rpm (peak horsepower that didn't destroy the motor) A lower pitch the boat accelerates quicker, air planes climb faster but neither goes its potential for speed. Now electric motors are different from gas. There is a pitch that works best for longevity (flying time) If I wouldn't have seen the second Dat. chart I would have thought that the left rear corner was heavy and the prop had to spin faster to hold up the corner. If you put the old and new props under a microscope you probably can't see a difference. Changing the props definitely brought the RPMs in line don't you think.

I have a boat with 28" props and if I hit something it is expensive to have them reshaped. However, they don't have to be perfect in order to drive it, and neither do the props on the drone. Even though a handful of drones did do uncommanded descents prior to this FW release, except for that, the user was unaware. If the prior FW hadn't throttled back and grounded the drone mid flight, the pilot could have flown it back. We are hoping that this update does nothing more than warn us that the props need replacing. I am not sure what that means if you ignore the warning. Does the ESC overheat? We do know that the drone won't drop out of the sky, because, as I said, in the prior cases of uncommanded descents, the drone was flying fine, till the FW decided it wasn't.. But if I get the warning, I am going to splurge and spend $12 and replace the props.

hallmark007 Posted at 4-27 11:50
It’s not clear that props are the problem, in fact far from it, it seems now you’re saying that those who had new props on had bad props but those who had props since November, well they’re ok , I think descending craft had a little more to it than props.
Do you really think those who had props stored in their bags could be stored wrong or those who use combo case some can have bad props but others are perfect.

I don't understand your reply, also because here you're saying I'm wrong, but in the next post you say I'm right...

This "Motor Error" warning (ignore the cases where there was an issue with the firmware update, which can be fixed by refreshing through DJI Assistant) instructs pilots to replace props on specific corner. Replacing props seems to make the warning go away. Are we in agreement on this?
If yes, then there is "something" with the props.

What is it, and how these "bad" props ended up on the MM (or as spares), it's the part we don't know. Bad from the start, damaged by improper storage, incorrectly matched by the user, incorrectly matched by DJI... all theories at this point.

hallmark007 Posted at 4-27 14:43
How do you explain those using combo case having no problems, in fact I’d safely say 95% are having no problems with props, mine are on now 5 months they’ve been in combo case since and have had no special treatment but work perfectly, is it props or not props or a combination ?

Combo case is fine. If you pack the drone away with the props horizontal across the drone body there is no issue. That's how the drone is supplied to you when you first buy it. It's people using rubber bands and those prop holders that put stress on the props on weird angles.

120ccpm Posted at 4-27 14:45
I don't understand your reply, also because here you're saying I'm wrong, but in the next post you say I'm right...

This "Motor Error" warning (ignore the cases where there was an issue with the firmware update, which can be fixed by refreshing through DJI Assistant) instructs pilots to replace props on specific corner. Replacing props seems to make the warning go away. Are we in agreement on this?

...seems to point at bad props which induce high RPM's in order to keep machine in steady/sustainable flight.

...and all that punishment we see all over and the mini-thing still flies steady?

Not sure its any interest or help but I took some screen grabs of my MM motor speeds. It's only a week old so I have included:
- The first-ever flight & flight from day 2
-  flight just before, where the warning was shown and flight just after
- test flights after refreshing the firmware with assistant software

I only had the issue show up once

I guess more telemetry is needed to really understand whats going on and I don't have the knowledge to really interpret these graphs very well but it does seem that motor speed of rear left has been constantly higher since day 1.

link to pdf with screen grabs - https://drive.google.com/open?id=1BOf7EQwbtavbYsZhdFUFXCImFW7RtsRR

deathsquad Posted at 4-27 14:34
You only have to understand that everything on this drone was made to keep weight down under 249g. The issue with the props has to do with how thin and lightweight they are. It means they are easy to warp or damage even in storage. I see some prop holders that hold the props on an angle which is ridiculous. The drone props have to be laid horizontally without any pressure on them the way they came when you bought the drone.

I don't see a lot of evidence (none in fact) of this. So many people use the cases, including myself, and haven't had any problems with props. This reminds me of an orange sky theory. The person argues that the sky is orange and no matter how clever and reasonable the argument seems, it has a serious problem. The sky isn't orange, it's blue. Likewise, it is easy to make up a theory that props are being ruined by storing them in cases, except almost all of us store them that way, and they aren't being ruined.

Deucalion Posted at 4-27 14:55
I don't see a lot of evidence (none in fact) of this. So many people use the cases, including myself, and haven't had any problems with props. This reminds me of an orange sky theory. The person argues that the sky is orange and no matter how clever and reasonable the argument seems, it has a serious problem. The sky isn't orange, it's blue. Likewise, it is easy to make up a theory that props are being ruined by storing them in cases, except almost all of us store them that way, and they aren't being ruined.

...agree, storage isn't a problem...some very exp dudes here have made stress-tests with weights on stored props...and the thing still flies good...so, back to square one?

120ccpm Posted at 4-27 14:45
I don't understand your reply, also because here you're saying I'm wrong, but in the next post you say I'm right...

This "Motor Error" warning (ignore the cases where there was an issue with the firmware update, which can be fixed by refreshing through DJI Assistant) instructs pilots to replace props on specific corner. Replacing props seems to make the warning go away. Are we in agreement on this?

Just saying that we have now proved that the cause descents is down to props, which you did with no proof in fact I still should be seeing proof of how bad these props are, I seen one staged photo that’s it, we now have the usual hysteria being spread about how combo case is the cause storing horizontally is the cause heat is the cause, bad batch is the cause, anyone can have bad props in storage that will cause the unknown descent.
So nothing solved and more hysteria created, it’s not about being right or wrong as you think. I have seen descents in pretty light wind in which craft can’t gain any ground and just goes backwards and down, now if 3 sets of props are working it would make sense that those 3 sets would at least make some headway.
So thinking this is only props and somehow you have proven yourself right is a bit presumptuous.

deathsquad Posted at 4-27 14:51
Combo case is fine. If you pack the drone away with the props horizontal across the drone body there is no issue. That's how the drone is supplied to you when you first buy it. It's people using rubber bands and those prop holders that put stress on the props on weird angles.

You make a good attempt at answering but it’s balder dash and without any proof.

hallmark007 Posted at 4-27 15:16
Just saying that we have now proved that the cause descents is down to props, which you did with no proof in fact I still should be seeing proof of how bad these props are, I seen one staged photo that’s it, we now have the usual hysteria being spread about how combo case is the cause storing horizontally is the cause heat is the cause, bad batch is the cause, anyone can have bad props in storage that will cause the unknown descent.
So nothing solved and more hysteria created, it’s not about being right or wrong as you think. I have seen descents in pretty light wind in which craft can’t gain any ground and just goes backwards and down, now if 3 sets of props are working it would make sense that those 3 sets would at least make some headway.
So thinking this is only props and somehow you have proven yourself right is a bit presumptuous.

"it would make sense that those 3 sets would at least make some headway"

...agree...3 sets should hold the thing aloft somehow....unless it's an issue with settling with power:

Deucalion Posted at 4-27 14:55
I don't see a lot of evidence (none in fact) of this. So many people use the cases, including myself, and haven't had any problems with props. This reminds me of an orange sky theory. The person argues that the sky is orange and no matter how clever and reasonable the argument seems, it has a serious problem. The sky isn't orange, it's blue. Likewise, it is easy to make up a theory that props are being ruined by storing them in cases, except almost all of us store them that way, and they aren't being ruined.

It's a plausible theory, though. I have not seen any evidence for other theories, at this point, so to me they are all possible. What's your favorite, or how do you explain why some props trigger this Motor Error warning?

Deucalion Posted at 4-27 14:55
I don't see a lot of evidence (none in fact) of this. So many people use the cases, including myself, and haven't had any problems with props. This reminds me of an orange sky theory. The person argues that the sky is orange and no matter how clever and reasonable the argument seems, it has a serious problem. The sky isn't orange, it's blue. Likewise, it is easy to make up a theory that props are being ruined by storing them in cases, except almost all of us store them that way, and they aren't being ruined.

The case is fine and storage is fine if they are stored correctly like I said, with props horizontal across body etc. I have seen people putting rubber bands across the props and putting them in the case though or those strap things off ebay where the top props are on angles under pressure. This can cause them to warp.

...btw, these unwanted descents ever happen with other DJI drones...?

No. Because they have sturdier propellers ;)

Answer is no and all I can say is I own and fly a magic pro 4 years old and the same props are on this drone since I got it, another thing I will say is that at that time everyone thought the props were very small and light .

120ccpm Posted at 4-27 15:28
It's a plausible theory, though. I have not seen any evidence for other theories, at this point, so to me they are all possible. What's your favorite, or how do you explain why some props trigger this Motor Error warning?

Sure, plausible, but entirely contradicted by evidence. We knew storage wasn't the issue when the descents first showed up. Why? Almost all of us were using cases and weren't having issues. The descents were random and some users just got their drone. I give credit to those who realized it was propellers early on, before the FW update. It was easy after the FW update. When a dozen users post "Hey, I updated the software and now I am getting errors!, wait, I replaced the props and now I am ok" it is pretty easy to conclude that there is an issue with propellers.

hallmark007 Posted at 4-27 15:16
Just saying that we have now proved that the cause descents is down to props, which you did with no proof in fact I still should be seeing proof of how bad these props are, I seen one staged photo that’s it, we now have the usual hysteria being spread about how combo case is the cause storing horizontally is the cause heat is the cause, bad batch is the cause, anyone can have bad props in storage that will cause the unknown descent.
So nothing solved and more hysteria created, it’s not about being right or wrong as you think. I have seen descents in pretty light wind in which craft can’t gain any ground and just goes backwards and down, now if 3 sets of props are working it would make sense that those 3 sets would at least make some headway.
So thinking this is only props and somehow you have proven yourself right is a bit presumptuous.

I said repeatedly that uncommanded descents (those where the MM would, out of the blue, start losing altitude and could not be stopped) might be triggered by bad props, but there is more to it, as a prop doesn't go back all of the sudden, in a way that makes the descent unrecoverable.

This particular "Motor Error", though, seems to be 100% about the props... it instructs pilots to replace props (not the motor, not the ESC, not the arm, not the battery, not anything else), and people say that's all it takes to make it go away. User GrahamJohnson10 provided excellent evidence of a motor experiencing high RPMs before, and normal RPMs after the replacement.

Only time will tell if - by introducing this warning in the latest firmware, and forcing pilots to replace props - DJI has effectively prevented the "uncommanded descents". I'd say there is a good chance, but of course it's pure speculation. Seems quite logical, though.

Instead of going down your usual road of judging my intentions, point out exactly what you think it's incorrect in my reasoning, and what you believe to be the correct interpretation for what we're seeing.

fans1cafe718 Posted at 4-27 15:38
...btw, these unwanted descents ever happen with other DJI drones...?

I don't recall any.

Deucalion Posted at 4-27 15:53
Sure, plausible, but entirely contradicted by evidence. We knew storage wasn't the issue when the descents first showed up. Why? Almost all of us were using cases and weren't having issues. The descents were random and some users just got their drone. I give credit to those who realized it was propellers early on, before the FW update. It was easy after the FW update. When a dozen users post "Hey, I updated the software and now I am getting errors!, wait, I replaced the props and now I am ok" it is pretty easy to conclude that there is an issue with propellers.

Like anything, there can be multiple causes for the same issue. i was just offering one cause being the way the drone props are stored causing an issue. I personally have no issue with my mini or props.

Deucalion Posted at 4-27 15:54
I don't recall any.

I don't think it has to do with the sturdiness of the props either. Because of all the hype about props and uncommanded descents, I was worried when I ran the props into something that I "ruined" them. But I am still flying original props. And I don't recall anyone "ruining" their props. The one user put up a pretty convincing RPM graph showing the RPM with one prop and then showing it with another.

Deucalion Posted at 4-27 15:53
Sure, plausible, but entirely contradicted by evidence. We knew storage wasn't the issue when the descents first showed up. Why? Almost all of us were using cases and weren't having issues. The descents were random and some users just got their drone. I give credit to those who realized it was propellers early on, before the FW update. It was easy after the FW update. When a dozen users post "Hey, I updated the software and now I am getting errors!, wait, I replaced the props and now I am ok" it is pretty easy to conclude that there is an issue with propellers.

I would not say it's contradicted by evidence, by I do agree it's not backed by any. The fact that many people use cases (myself included) and have no problems doesn't say much, though, as here we're trying to understand what happens to a minority of users. The majority might put the MM in the case with the props properly arranged, others might not pay attention. Or some cases are worse than others... anyways, pure speculation, but until the underlying issue with propellers is explained, I think we should keep all options open.

Say we rule out improper storage, what would be your best guess?

120ccpm Posted at 4-27 16:41
I would not say it's contradicted by evidence, by I do agree it's not backed by any. The fact that many people use cases (myself included) and have no problems doesn't say much, though, as here we're trying to understand what happens to a minority of users. The majority might put the MM in the case with the props properly arranged, others might not pay attention. Or some cases are worse than others... anyways, pure speculation, but until the underlying issue with propellers is explained, I think we should keep all options open.

Say we rule out improper storage, what would be your best guess?

"I would not say it's contradicted by evidence, by I do agree it's not backed by any."

You Hypothesize that storing a drone in a case distorts the props and causes motor errors. You store 1000 drones in cases, and yet no errors. That doesn't disprove your hypothesis?

"Say we rule out improper storage, what would be your best guess?"

They were malformed at the factory. A bad batch of props.

fans1cafe718 Posted at 4-27 04:50
...nice....rear-left working much harder than rear-right...let alone fronts...very interesting.

Is this with no wind and hover?

There was wind and the graph is taken from not a hover but an actual flight, but as you can see the left rear and also the right rear motors where spinning faster than the front two.

djiuser_xiKkRfWbTNKe Posted at 4-27 06:03
Breaking my promise to keep quite

How do we analyse the .Dat like that?

I use a windows program called CSVView to analilize the .DAT files.

This is before the fix



And this is after renewing the pops on both rear motors

120ccpm Posted at 4-27 15:54
I said repeatedly that uncommanded descents (those where the MM would, out of the blue, start losing altitude and could not be stopped) might be triggered by bad props, but there is more to it, as a prop doesn't go back all of the sudden, in a way that makes the descent unrecoverable.

This particular "Motor Error", though, seems to be 100% about the props... it instructs pilots to replace props (not the motor, not the ESC, not the arm, not the battery, not anything else), and people say that's all it takes to make it go away. User GrahamJohnson10 provided excellent evidence of a motor experiencing high RPMs before, and normal RPMs after the replacement.

“GrahamJohnson10 provided excellent evidence of a motor experiencing high RPMs before, and normal RPMs after the replacement.”


I think post by GJ shows that although he got a warning craft flew ok, no suspect craft descending on its own, so are we to think that bad prop caused it but bad prop didn’t cause craft to descend, was his prop not so badly damaged , why can’t we physically see the damage to the prop, I think the hysteria caused by trying to contend that bad props are caused by incorrect storage is totally unfounded and GJ log does not show this either. And it’s clear by reading this thread that the conspiracy theorists have gathered to try whipping up their usual BS, and I’m talking about those who don’t even own a mini, so bad information continually gets spread leading to users being genuinely afraid to use their drones of which vast majority have little or no problems.

fans1cafe718 Posted at 4-27 06:08
Airdata.com...?

Airdata.com will not give you as much info as using CSVView will.

Deucalion Posted at 4-27 17:03
"I would not say it's contradicted by evidence, by I do agree it's not backed by any."

You Hypothesize that storing a drone in a case distorts the props and causes motor errors. You store 1000 drones in cases, and yet no errors. That doesn't disprove your hypothesis?

You Hypothesize that storing a drone in a case distorts the props and causes motor errors. You store 1000 drones in cases, and yet no errors. That doesn't disprove your hypothesis?

No, because we're not doing the experiment 1000 times in controlled fashion. You have 1000 different people putting the drone in the case, in 90% of the cases (pun not intended) the props end up in the right place, 10% end up in a way that puts stress on them. Heck, I've seen photos of people using rubber bands to keep them in place! I'm not particularly in favor of this theory vs. another one, I think a bad batch is a definite possibility too, but I have not seen any evidence of that either. Maybe it's nothing visible, maybe it's the type of plastic they used, or maybe it's a combination of bad plastic and improper storage... honestly, I think all possibilities are open, and likely we'll never know.

At the end, I think this Motor Error is a good way for DJI to spot prop issues before they turn into something worse. As I responded to Hallmark, we don't know if this will fix the uncommanded descents, but hopefully it will.

fans1cafe718 Posted at 4-27 06:55
Great info...thank you so much!

So, might be a storage problem.

One of the most important things to do is to disable the "sync with DJI" in the DJIFLY app as it deletes the .DAT files from your mobile device once it has synced the data with DJI.  

hallmark007 Posted at 4-27 17:14
“GrahamJohnson10 provided excellent evidence of a motor experiencing high RPMs before, and normal RPMs after the replacement.”

I think most understand that the drone was still flyable, but that the FW forced it to land. Nonetheless, the instigator was the prop causing the rpm increase triggering the FW to force a landing. The expectation is that the new FW will just warn us of the condition but not force a landing.

Deucalion Posted at 4-27 07:13
The storage does not affect the props. We at least know that much.

Sorry but looking at the reports in here, your are wrong.

Occams Razor Posted at 4-27 08:31
Probably the most useful post on this string.  Thank you for publishing data and not hyperbole.

Thank you.

hallmark007 Posted at 4-27 17:14
“GrahamJohnson10 provided excellent evidence of a motor experiencing high RPMs before, and normal RPMs after the replacement.”

Don't bring you personal feuds with other people into the mix, please. The post from GJ shows what I think it's pretty obvious by now, which is that there are some props that have an issue. You replace them, things go back to normal (no Motor Error warning). Uncommanded descents are another story, and we can only wait and see if they will continue. My guess: they won't.

Back to what causes the Motor Error, do you think it's un-matched pairs? I asked a couple people, they said their props matched...

By the way, do you ever sleep? It's frikking 2:30am in Ireland...

grahamjohnson10 Posted at 4-27 17:20
Sorry but looking at the reports in here, your are wrong.

I did look at the reports here. If you have a 1000 users storing their drones in cases and only a handful of users with prop issues, not only does storing your done in a case not cause prop issues, they aren't even correlated. I know how those crazy notions start, and I explained it in a previous post. People start wondering why something happens and then come up with a plausible reason (storing in cases). They get so excited, they forget to LOOK AT THE DATA and see if their hypothesis even makes sense. Some get so excited they cut their case all up.

djiuser_D15Af7IgCNYj Posted at 4-23 23:08
I mean the message stays away

Do u mean the message webt away and didn't appear anymore?

Deucalion Posted at 4-27 17:41
I did look at the reports here. If you have a 1000 users storing their drones in cases and only a handful of users with prop issues, not only does storing your done in a case not cause prop issues, they aren't even correlated. I know how those crazy notions start, and I explained it in a previous post. People start wondering why something happens and then come up with a plausible reason (storing in cases). They get so excited, they forget to LOOK AT THE DATA and see if their hypothesis even makes sense. Some get so excited they cut their case all up.

And looking at the data doesn't mean looking at the handful of users with prop issues and whether they stored their drone in a case or not. It means looking at the 1000 users who stored their drones in a case and whether they had prop issues. The former (looking at whether the handful stored their drone in a case) is an inverse fallacy.

120ccpm Posted at 4-27 17:17
You Hypothesize that storing a drone in a case distorts the props and causes motor errors. You store 1000 drones in cases, and yet no errors. That doesn't disprove your hypothesis?

No, because we're not doing the experiment 1000 times in controlled fashion. You have 1000 different people putting the drone in the case, in 90% of the cases (pun not intended) the props end up in the right place, 10% end up in a way that puts stress on them. Heck, I've seen photos of people using rubber bands to keep them in place! I'm not particularly in favor of this theory vs. another one, I think a bad batch is a definite possibility too, but I have not seen any evidence of that either. Maybe it's nothing visible, maybe it's the type of plastic they used, or maybe it's a combination of bad plastic and improper storage... honestly, I think all possibilities are open, and likely we'll never know.

"No, because we're not doing the experiment 1000 times in controlled fashion."

There is no difference in this case. We have 1000 users putting their drones in and out of cases dozens of times. You can't get any more large or random. It is an experiment, done already for you.

What you seem to be describing is if there is a way to put a drone in the case such that you might damage the props. And you would probably have to do several experiments to find out the answer to that question. One obvious way would be to push it in with the props extended.

But, do we really need to know if there is a way to put a drone in a case and damage the props, since we see no evidence of anyone actually doing that amongst 1000 users dozens of times?

Well... looks like .dat evidence has arrived. Thanks @grahamjohnson10

We've had already several users both here and other forums fixing the drop issue (ESC nef related) with rear props swap.

There's nobody more stubborn than those who turn a deaf ear and a blind eye on everything that's been posted to date.

Do you fancy charlatans everywhere? Feel free to stuff your head under the sand and downgrade your firmware without speed check on the motors: good luck for your flights!

And PLEASE DON'T COME BACK here whining about the drone dropping with ESC nef errors and DJI not being able to make drones anymore.