The inertia of the rotor helps a lot stabilize an autogyro. You don't get the same inertia in a small drone. One can certainly invoque a square/cube law there.

The inertia of the rotor helps a lot stabilize an autogyro. You don't get the same inertia in a small drone. One can certainly invoque a square/cube law there. There are scale model autogyros around the 1 or 2 Meter rotor diameter scale, but I haven't seen anyone do smaller - maybe there is, in ultralight indoor flying.