On a full-size chopper the blades are probably composite, but are very long compared to the diameter of the (usually turbine) motor. The motor is metal, but spinning far faster than the rotor.
Which has more inertia? Dunno.
But on most drones it's plastic blades connected to an electric motor. The blades probably have very little inertia compared to the mass of the drone. And electric motors don't "coast".
To auto-rotate you need something that can build inertia on the way down to be used to soften the landing. Unless I really misunderstand how auto-rotation works.
...
So I just looked it up and the motor is disengaged during auto-rotation, so it's purely the stored energy in the rotor that's used. So definitely not going to work with the super-light blades on drones this size.
Which has more inertia? Dunno.
But on most drones it's plastic blades connected to an electric motor. The blades probably have very little inertia compared to the mass of the drone. And electric motors don't "coast".
To auto-rotate you need something that can build inertia on the way down to be used to soften the landing. Unless I really misunderstand how auto-rotation works.
...
So I just looked it up and the motor is disengaged during auto-rotation, so it's purely the stored energy in the rotor that's used. So definitely not going to work with the super-light blades on drones this size.