The uncommanded descent problem of the mini is caused by prop flattening ( pitch change ), ...
Correct !
... caused by prop flattening ( pitch change ), not prop bending.
Prop bending is what
causes the pitch change.
I am not convinced that the barely noticeable bending demonstrated in your photo can cause any problem.
I wasn't convinced at first either. In fact, it was only noticeable that the original blades were indeed bent when directly comparing them to brand new replacement blades.
I had always carefully stored mine "properly" nested in the Fly More case. It was only the introduction of the new Motor Speed Error warning in firmware v01.00.0500 that prompted me to take a closer look at the propeller blades. There was
nothing visibly wrong with the original blades. No knicks, no gouges, no scratches. They looked perfectly pristine.
But the warning recommended changing the left-rear blades, so I did. That's when I could see the obvious difference. You say the difference is "
barely noticeable" in my photo. But it
is noticeable.
If your rear blades slide effortlessly to nest together when folded across the Mini's body, then it's a sure bet they're
already bent. New straight replacement blades cannot be nested together without bending because of the outward angle at which the rear motors are mounted.
The blade bending can be very subtle. If you are still skeptical that such a
barely noticeable bending of the prop blades can cause sufficient prop flattening and pitch reduction to affect motor speeds, a very simple and conclusive measure is the
hover test.
The data plots of my motor speeds proved conclusively that the original propeller blades had lost pitch angle, as described in my
second link above.
Find an open space, preferably indoors to eliminate any wind interference. Press auto-takeoff, let the Mini hover hands-free for a few minutes, then press auto-land. Plot the motor speeds from your DAT file using CsvView. See
this recent post for instructions. Or if you can't figure how to do that, send me your DAT file and I'll plot the motor speeds for you.
With healthy new props installed, each of the Mini's motors should run at about 9600rpm in hover. If your blades have lost pitch angle, the motors must run faster to generate the required lift. If your blades are significantly deformed the motors will eventually reach high enough rpm to trigger the Motor Speed (or Propeller Speed) Error warning with recommendation to replace the blades. If you ignore that warning, you may eventually encounter a situation where the motors are unable to run any faster to generate the lift required to stay airborne and the Mini will suffer the dreaded "uncommanded descent".