axial flux motor question !!

[Punx0r]

Job jobbed...

200Nm @ 720rpm is approx 15KW. You ought to be able to take your pick of ~20KW commercially-available brushless motors.

 

[fdracing]

there's no way to use commercial motors , I want them to be part of my rotor , without any mecanical reduction , my co-axial helicopter has to be light as possible and "simple" as possible , that's why I plan to do the motors myself .

when you know how an co-axial rotors works , you understand the all thing :wink:

 

[Punx0r]

Have you considered radial flux electric motorcycle hubmotors? They will have the sort of speed range you require and you *might* be able to find one that can sustain the torque level you require.

My observation is that you wish to design and build an unprecedented motor for, of all things, a helicopter. The application requires a very high power density and reliability.

I would have thought such a demanding task would suit a person with many years' experience designing commercial electric motors. I think you must honestly ask yourself if you have the required skills for this task?

I know that I would not dare attempt it

Perhaps if you show a design sketch/model if your proposed rotor/drive configuration perhaps someone may be able to suggest alternative methods of powering it with a conventional motor? There already exist several high quality, high power, low weight motors designed for ultra-light electric aircraft.

 

[fdracing]

I already asked some quotations , prices were 10.000 euro each and I need two motors :? , I have seen myself some of them , I think those prices are unacceptable

I know what are my limits , very well :wink: , and I know what is my will , very well too :wink:

infos are somewhere and so everywhere, and i got already some, very interesting , I did stuff in my live that were well over my skills at the time , so , it's just one more :wink:

my background is mécanical engineer ,I used to design and build vacuum coating machines , and I worked also on racing motorcycles engines .

step by step I build my understanding on electric devices :wink:

Impossible is not French lol

there are not so many good motors as you think :? , and as I said my motors should be integrated at the rotor

 

[Miles]

Why are you reluctant to use an iron core? The effect of parasitic drag on autorotation? If you think you will save weight, you couldn't be more wrong.......

 

[fdracing]

autorotation is not my immediate problem ( the rotor design with an special collective pitch control include that possibility ) but i'll be able to climb first

the design I choose , doesnt include iron coils core, because of the wheight , my overal target is 300 kg including an heavy battey pack ( and an heavy pilot !!) , so each pound is a pound :wink:

i'll may be wrong , as far as you explain to me how much :wink:

in my design the iron is for the magnets , coils are to thin , and air core , for the moment !!

but why not, at the end the target in known , i should have that torque for flying

making an laminated iron core with an axial flux motor , other than TORUS is not easy

 

[Miles]

It will be difficult to even match the specific torque of an iron cored motor, let alone surpassing it.

 

[Miles]

( and an heavy pilot !!) , so each pound is a pound :wink:

So, you know what to concentrate on then...

 

[parabellum]

the design I choose , doesnt include iron coils core, because of the wheight , my overal target is 300 kg including an heavy battey pack ( and an heavy pilot !!) , so each pound is a pound :wink:

Sure, you can lift 300kg with 30KW?

 

[dotrick]

autorotation is not my immediate problem ( the rotor design with an special collective pitch control include that possibility ) but i'll be able to climb first

the design I choose , doesnt include iron coils core, because of the wheight , my overal target is 300 kg including an heavy battey pack ( and an heavy pilot !!) , so each pound is a pound :wink:

It's not a toy? a real helicopter???

 

[jkbrigman]

Not hard to believe:
https://www.youtube.com/watch?v=oD8TfjDMYT0&noredirect=1
and...
http://www.sikorsky.com/Innovation/Technologies/Firefly+Technology+Demonstrator

 

[fdracing]

have you guys see the NorciaVelo 16" motor , it look's like mine , and has all the numbers , +/- that I look for :wink: , which means , it's possible

 

[fdracing]

Sure, you can lift 300kg with 30KW?

nobody can be sure as far as it's already done , but i dont worry , power is important but not all , torque is the point , a perfectly design rotor and blades is also very crucial ,and that parts af my skill :wink:


the NorciaVelo design is a state of art , especially the stator

 

[parabellum]

Sure, you can lift 300kg with 30KW?

nobody can be sure as far as it's already done , but i dont worry , power is important but not all , torque is the point , a perfectly design rotor and blades is also very crucial ,and that parts af my skill :wink:


the NorciaVelo design is a state of art , especially the stator

Sikorsky example in above post is at least 1.5x more force armed and makes 5-15 min. flight, clamed >95% efficiency motor. Bad ass batteries of some kind special chemistry. HK Nano techs? :lol:

 

[fdracing]

today starting to work with FEMM 4.2 , it make some more sens to me now !!!, is there the same tool in 3D , and is it for you a reliable tool

i think i finally chosse my coil shape , it look's like a long thiny drop , i am learning from you guy's :wink:

especialy , Miles , lebowsky and some others :wink:

do you know the software : KOIL 1.1 and if so , what do you think about it

 

[Miles]

today starting to work with FEMM 4.2 , it make some more sens to me now !!!, is there the same tool in 3D , and is it for you a reliable tool

There's no equivalent in 3D, I'm afraid. You can work on linearised circumferential sections in 2D. I did them at: 1/6; 1/2 & 5/6 of the active area.

do you know the software : KOIL 1.1 and if so , what do you think about it

http://www.endless-sphere.com/forums/viewtopic.php?f=30&t=53088 I never got round to trying it. If you do, please report back!

 

[fdracing]

First test , i put my rotor drawing into FEMM , the field strength is not too bad , 12 mm air gap , 3 x round magnets 20 mm x 10 mm per rotors.


I love that software !!! it give's me lots infos :wink:

 

[Miles]

Hi fd,

Have you defined a boundary and added a property for "air"?

 

[fdracing]

i left the property of air as it was , and for the boundary i'll take any advice for it :wink:

here is the all rotor with some mod's on the left side , and as it originaly was on the right side

 

[Miles]

As long as the air is enclosed in a rectangle or circle, so that it doesn't escape, you're fine....

 

[fdracing]

ok , i got it

 

[Miles]

 

[fdracing]

i also try to change air by a diamagnetic gaz , like O2 , it helps a little bit , but hard to do in reality

 

[Miles]

i also try to change air by a diamagnetic gaz , like O2 ........

Try N2O....

 

[Lebowski]

still, in the FEMM simulations shown above the flux path closes through the axle, which I think is not correct.
I imagine in real life it will close through the neighbouring sets of magnets and the axle will be flux free...