Why?

[orfordness]

Hi Folks, OK, quick question from my wife';s friend...

I multicopters are so stable etc, why have they not been adopted as full size aircraft?

my own thoughts are about power/weight and electric vs piston\jet power...


Steve

[teslahed]

Multirotor stability comes as a result of electric motors which are able to speed up and slow down at a high rate of speed governed by an electronic speed controller and flight controller with the right sensors and processor.

It would be difficult to get the same effect with a non electric motor and on larger scale aircraft battery performance is too poor to be practical. If you think we get 10 mins or so with our small multirotors - that';s not really enough to compete with helicopters which already exist and work very well.

I expect this will change in the future because so many people have an interest in improving battery technology and electrical energy storage for so many reasons - once one of these systems is up to spec i expect we';ll see all sorts of full size multirotor aircraft.

I do wonder if you could make a practical hydrocarbon powered multirotor aircraft with variable pitch blades - like a full sized version of the stingray - and whether or not that would side step the issues with petrol motors not being great for speed control.

Maybe it';s just that no one has tried?

[teslahed]

Of course there are people working on this;

http://youtu.be/L75ESD9PBOw

http://youtu.be/CzP0Zqxam7E

Even Lady Gaga is in on the act;

http://youtu.be/VFsh_RNiAG0

[Biffa]

Still no manned flight of the Volocopter?

[teslahed]

Still no manned flight of the Volocopter?

Looks like Gaga beat them to it!

The first prototype has been flown with a guy sitting on top but like yourself what i really want to see is their latest production model up in the air at altitude flying properly.

[Hands0n]

Multirotor stability comes as a result of electric motors which are able to speed up and slow down at a high rate of speed governed by an electronic speed controller and flight controller with the right sensors and processor.

It would be difficult to get the same effect with a non electric motor and on larger scale aircraft battery performance is too poor to be practical. If you think we get 10 mins or so with our small multirotors - that';s not really enough to compete with helicopters which already exist and work very well.

I expect this will change in the future because so many people have an interest in improving battery technology and electrical energy storage for so many reasons - once one of these systems is up to spec i expect we';ll see all sorts of full size multirotor aircraft.

I do wonder if you could make a practical hydrocarbon powered multirotor aircraft with variable pitch blades - like a full sized version of the stingray - and whether or not that would side step the issues with petrol motors not being great for speed control.

Maybe it';s just that no one has tried?

The interim to full-on storage would be portable generation. That is, being able to carry generators of sufficient capacity to drive the all-essential electric motors.  Of course, it all adds weight but that is currently a given with all of our incumbent storage technology.  There is still nothing that approaches the convenience and [at the point of use] efficiencies of internal combustion engines, be they jet or piston.   So a hybrid powered multi-rotor?  What hasn';t that been attempted? Or are designers such as the eVolo mob simply too narrow focussed to consider such a method?

I do not believe that storage will ever be the solution, although it will have its place functionally.  Certainly not if we';re going to rely upon pure chemistry, and at this stage of our imagination what else is there?

But hybrid powered would appear to be a way forward, if we can reduce the size of the generation plant.

[Col_M]

Along with the reasons already mentioned it';s also down to the efficiencies, on rotor craft one big rotor is more efficient at lifting loads than four (or more) smaller rotors.
Fuel efficiency is a big deal and companies operating helis want fuel to eat into their profit margins as little as possible. More rotors also means more maintenance and cost.