>>>>If 4 is good, 54 must be great:
>>>>
>>>>http://www.theregister.co.uk/2015/09/04/quinquaquadcopter/
>>>
>>>Guess there aren't too many ways of getting airborne for £6k (unless you count a hovercraft) :-}
>>>
>>>And controlling 54 rotors in a way that provides stability and control must be a bitch.
>>>Nice to see that he's included the obligatory British umbrella though......
>>
>>For roll, vary the power to rotors at the left and right sides. For pitch, rotors to the front and rear.
>>
>>As the article says, yaw is a problem. I don't know how "conventional" small quadcopter drones do it. I imagine they have counter-rotating props so at level, steady altitude and bearing there's no net torque. They're typically small enough to have a small polar moment of inertia. So, it might be possible to yaw by varying the power/torque to the sets of counter-rotating props - more to one set and/or less to the other.
>
>On simple (i.e. 4-rotor) versions yaw is indeed controlled by speeding up one pair of blades and is very controllable - difficulty would be applying that principle to so many rotors at varying distance from the cog.
>
>I've got access to the DJI SDK's (Mobile and Onboard) but haven't found time to play with them.....
>
>>Mr. 54 has a high polar moment of inertia. That might be addressed by mounting more rotors tangentially around the rim. Another option would be to put vanes below the craft, in the downwash of the props. They could be servo operated to deflect the downwash one way or the other.
>>
>>Of course, it was only a matter of time before someone took advantage of the superior energy density of Jet-A: http://www.quadhangar.com/jetquad-jet-engine-powered-quadcopter/
>>
>>Thrust/weight ratio better than 3:1!
>
>I would have thought the response times for varying speed would be too slow to provide good maneuverability.

Yes, poor throttle response and poor fuel efficiency at "idle" are two reasons turbines never succeeded in passenger cars. I don't know the response of the micro turbines, probably still not a good as similarly sized IC or electric.

Here's one hybrid approach: https://www.youtube.com/watch?v=InvFPZixDwY

Turbines are efficient at or near full throttle, so one approach might be to size the turbine to support, say, 90% of the vehicle weight, then handle the rest of the lift and flight control with "conventional" rotors.

InvFPZixDwY