You're looking at a fixed wing aircraft though with one of those. What's made the quadcopter drone possible is the high torque and instantaneous throttle response of small electric motors, combined with fast control electronics. The conventional way to fly a small helicopter is just like a full sized helicopter, with a main rotor and a mechanical swash plate.

With the right control electronics, these can easily be made into drones, but people tend to not like them as much anymore because they're mechanically complex and finicky. The electric motors are simple, and when one goes bad you just drop in a new one.