MM Folded Rear Prop Bending per DJI Instructions

[rumitcu]

I think you're on to something there, and agree with what you're saying. Even if you do take care to position the prop blades "correctly" into the troughs in the flymore case to ensure the case itself is not putting any pressure on the blades, I think the blades are still being bent just by forcing them to nest together like this.

I have always stored my Mini in its Flymore case between flights since its purchase in December with no apparent consequences. But on the very first flight since upgrading to v01.005 firmware I received the Motor Speed warning with instructions to replace the left-rear prop blades.

Prior to installing the new blades, the rear props always seemed to slide over/under each other to nest easily in the Flymore case. But I notice the new blades now cannot slide under/over the opposing motor's blades unless one side or the other is bent up/down.

I wish I had taken a "before" photo as well, because previously the blades slid together to nest easily together. But now, with new blades installed on the left-rear, and the original blades still on the right-rear, you can see that they can no longer nest together without deforming one side or other. Putting fresh right-rear blades would make it even more obvious.View attachment 100321

Thanks for the feedback. I think you might be the first person who understood the intent of my original post. It's interesting to note that you didn't notice much pressure when nesting the rear props together until you replaced the left-rear blades. When I noticed the interference/bending, it was also after replacing the props. Your anecdotal evidence seems to suggest that the props take on a new shape after being stored per DJI's instructions, which further supports the idea that the props are highly malleable and can take on a new shape based on how they are stored. Definitely not a good design characteristic for propellers.

 

[Zbip57]

Your anecdotal evidence seems to suggest that the props take on a new shape after being stored per DJI's instructions...

Exactly!
Mine has never been crashed. I've never abused the props in any obvious manner. They otherwise look pristine. No knicks, scrapes, or wear whatsoever.
I've always packed the Mini back in its Flymore case immediately when finished flying. Although I cannot rule out as impossible that the props have ever been jammed in there incorrectly, I'm convinced it's highly unlikely because I'm always careful with my equipment. The storage case has obvious troughs into which the props are meant to fit.
I really do now suspect that the prop deformation might be a result of the way the blades are forced to bend whenever crossed over each other like that, even if stored properly in the case.
The difference between the old left-rear props and the fresh left-rear props was quite apparent to me when I took that photo posted earlier. Even holding the old prop blades on top of the new blades, I could see the old ones had drooped and flattened (lost some of their twist). The Mini has not gone back in its case since then.
The strange thing is, when I compare the old and new blades again now, I can no longer see any difference whatsoever. Bizarre. It as though, when left alone, they eventually spring back to regain their initial shape.

 

[Zbip57]

Another thought, I've read on another forum that someone received the Motor Speed warning and instruction to replace props on a brand new Mini first time flying. How can the props have gone bad already?

My Mini, with props installed, was shipped to me packed in its Flymore case. There's no telling how long these things are stored that way before arriving at your door.

Is the regular Mini, not the FlyMore Combo, also shipped with the props folded?

 

[sar104]

Exactly!
Mine has never been crashed. I've never abused the props in any obvious manner. They otherwise look pristine. No knicks, scrapes, or wear whatsoever.
I've always packed the Mini back in its Flymore case immediately when finished flying. Although I cannot rule out as impossible that the props have ever been jammed in there incorrectly, I'm convinced it's highly unlikely because I'm always careful with my equipment. The storage case has obvious troughs into which the props are meant to fit.
I really do now suspect that the prop deformation might be a result of the way the blades are forced to bend whenever crossed over each other like that, even if stored properly in the case.
The difference between the old left-rear props and the fresh left-rear props was quite apparent to me when I took that photo posted earlier. Even holding the old prop blades on top of the new blades, I could see the old ones had drooped and flattened (lost some of their twist). The Mini has not gone back in its case since then.
The strange thing is, when I compare the old and new blades again now, I can no longer see any difference whatsoever. Bizarre. It as though, when left alone, they eventually spring back to regain their initial shape.

It's certainly possible that they can revert to original shape, at least to some extent. The first time I deformed them and ran tests I saw almost immediate uncommanded descents. When I repeated the tests the following day it took several minutes of flight before the problem re-appeared.

 

[Zbip57]

It's certainly possible that they can revert to original shape, at least to some extent.

I've read your flight log analysis and it's fascinating!

I straight away downloaded the CsvView software, but then struggled for three days to get it to work. It kept insisting I need to install Java Run-Time-Environment. But the link provided goes to the full Java package which, even after multiple attempts at installing/deleting/reinstalling, still pops up the same message. Need Java RTE.

Much head-scratching and Google searching ensued. Finally I stumbled onto a download page that offered just the Java RTE, but that required first registering an account (free) with Oracle. Sheesh.

I've been playing with CsvView non-stop ever since then. Wow! There sure is a lot of info packed into those log files! ?

 

[sar104]

I've read your flight log analysis and it's fascinating!

I straight away downloaded the CsvView software, but then struggled for three days to get it to work. It kept insisting I need to install Java Run-Time-Environment. But the link provided goes to the full Java package which, even after multiple attempts at installing/deleting/reinstalling, still pops up the same message. Need Java RTE.

Much head-scratching and Google searching ensued. Finally I stumbled onto a download page that offered just the Java RTE, but that required first registering an account (free) with Oracle. Sheesh.

I've been playing with CsvView non-stop ever since then. Wow! There sure is a lot of info packed into those log files! ?

You maybe had the 32-bit Java version previously - CsvView requires 64-bit.

 

[delyle]

I don't use the fly more case: I store my Mini in a camera bag and use 3D prop protection from this source: DJI Mavic mini prop holder by julmo99
View attachment 99677

 

[delyle]

I don't use the fly more case: I store my Mini in a camera bag and use 3D prop protection from this source: DJI Mavic mini prop holder by julmo99
View attachment 99677

That's great IF you have a 3D printer.

 

[delyle]

My single rubber band holds my props just fine - no issues so far.

Best idea I've seen so far. Gotta get me one of those rubber bands.