There are two things that can happen with prop blades as motor rpm increases:
1) As the rpm increases, the torsional (twisting) stresses along the length of the blade increase, and the flexible plastic blade will tend to 'feather' into the airflow - especially out toward the tips - which reduces the 'pitch' and lifting ability of the prop.
2) In addition, the inner part of the prop with the coarsest pitch will hit a speed where it stalls. Not only is the blade-stall going to massively reduce the lifting ability of that blade, but it will upset the airflow behind it so that its partner on the other side of the hub, will be trying to gain lift in dead air. If not the same as - this would be similar to the effect of 'cavitation' on a ship's propellor.
It appears that the software in the Mavic Mini is written to simply increase rpm when additional lift is required - and in their 'normal' shape, the MM DJI prop's will accommodate. However, if the Mav' has been stowed in a way that warps the blades (i.e. reduces their pitch - see my post #19), then those prop's are going to be more effective at lower rpm than they are at high! The reason for this is that the flattened tips provide almost no lift, and the course-pitched inner part of the prop will do all the work right up to the point where it stalls and suddenly stops providing any lift at all. In the stalled & over-rev'd condition, the prop's are going to act like a flat disk of plastic with some parachute-like facilities - which explains why the MM doesn't just plummet but tends to lower itself using the front motors to maintain horizontal stability.
This also explains why 'flying backwards' is going to be an effective way to rescue a MM in this condition ... It's because when the MM is flying backwards, the prop's providing the 'power' are the unaffected front set, while the rear set don't have to rev' so high - and are simply providing a bit of lift.
My conclusion is that if the Mavic Mini is stowed incorrectly with pressure placed on the rear prop blades in such a way that they deform and 'flatten' - the Mavic will need to use higher motor rpm to get an equivalent lift from the prop-set. Under 'no-stress' flight conditions, the MM should fly as normal, but higher prop rpm (higher pitch sound) will probably be noted. However, if the MM needs 'power', the motor rpm maxes out and the blades will stall and become almost ineffective. The Mavic's motor controllers will keep the rpm high in an attempt to regain lift, which will maintain the stall until downward drift stops (e.g. the MM bounces off the ground into a hover). I believe that the flight data analysis that has gone on in this post, backs that up ... I also believe that it is going to be impossible to replicate this problem on a Mavic Mini that has been stowed correctly in the FlyMore case, or is usually stowed some other way.
In my opinion, the two ways to remove this problem (after changing the rear props), are:
1) very careful stowage to ensure that the prop-blades stowed under the MM have not swung backwards and are being compressed under the body of the drone while it is in the FlyMore case.
2) and/or - use of a 3rd party prop made from a stiffer composite material which will not deform.
Sam Karp interviews Radiomaster Controllers at the 2024 EXPONENTIAL