Re: Raises an interesting question
Gliding requires wings: On a drone, those are dead weight and drag inducers for all the flight envelope for the entire life of a vehicle unless its actually used in an accident.
Autorotation requires a large rotor surface to convert its kinetic rotating energy to a large amount of lift in a very short space of time by changing the pitch of the blades using cyclic. No matter the size of drone, you don't have the cyclic system on any rotor as that would introduce a massive weight and complexity penalty, so you cannot autorotate at all.
Parachutes cannot deploy quickly enough ti be useful under certain heights, so the Dead Man's Curve for a manned drone is huge compared to a heli.