A philosophical/technical question about # of rotors

[Dark Skies]

So I'm sitting and musing about things last night, and I got to wondering, why are multi-rotor (usually four) configurations so ubiquitous in the consumer/recreational drone space? Is there a practical technical reason for this? Are there any single/dual rotor consumer drones? I know that r/c copters are a thing, why not make them semi-autonomous, ergo, drones? And if there is something better about quadrotor setups, why aren't there any (or more) full-sized, passenger-capable quadrotor aircraft? I'm interested to hear any thoughts/insights on this.

 

[Fred_G]

Probably not used for manned flight due to chances of one motor going out and it crashing. Would be 4 times the failure chance of a helicopter.

 

[Dark Skies]

Probably not used for manned flight due to chances of one motor going out and it crashing. Would be 4 times the failure chance of a helicopter.

Yes, that makes sense. To my original question, why is the quad+ configuration so popular with small UAVs?

 

[Dark Skies]

Yes, that makes sense. To my original question, why is the quad+ configuration so popular with small UAVs?

Okay, I decided to look up some tech sheets about this, which in retrospect I should've figured out - a single rotor drone would have a miniature version of the ridiculously complex drivetrain of a manned chopper, swash plates and all the other tech necessary to manipulate that one rotors blades to provide directional control. With multirotors the only thing necessary is to vary the rotational speed of each motor to getcha where you want to go, no pivoting blades or swiveling masts. Cool, got it. Now to the next question I'll come up with while drunk. Cheers.

 

[phph001]

Probably not used for manned flight due to chances of one motor going out and it crashing. Would be 4 times the failure chance of a helicopter.

That's not entirely fair. bearing in mind that single engine failure is less serious in 4-engined aeroplanes than in 2-engined aeroplanes, and in turn single failure is less serious in 2-engined than in in single-engined. If one specifies that in a 4 motor drone two are sufficient to keep it aloft then the third can be used to control pitch/yaw/roll as appropriate