# "Magnetic Gears" may provide frictionless CVT



## david85 (Nov 12, 2007)

Certainly an interesting idea. I wonder if this principle really could be applied to a CVT but without the weak, high friction versions that are out there now.

The other solution would be to go to a high efficiency motor/generator method of power transmission. But there aren't many motors or generators out there that are over 98% efficient and thats before losses in the controller(s).


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## PhantomPholly (Aug 20, 2008)

As for "how" to make it into a great CVT, I don't know although I can certainly imagine clutchless shifting. It'll take someone smarter than me to engineer that...

I perceive this as an enhancement to a high efficiency motor/generator, keeping the power/efficiency at the optimal rpm for the job at hand (e.g. best motor rpm for accelleration/regeneration). It will be a very long time before we have motors that are both very efficient AND operate that efficiently over a great range of rpms; thus, some kind of transmission will always improve performance.


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## _GonZo_ (Mar 23, 2009)

Certanly very interesting.
With that high efficiency will let us use very hig revolutions motors 
That will be really good


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## IamIan (Mar 29, 2009)

interesting video as well.

The noise issue during disengagement would need to be fixed as well.

http://www.magnomatics.com/Video.aspx


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## dataman19 (Oct 7, 2009)

Excellent video....
..
Now to apply this to EVs! 
Then to EPs (Electric Planes)..
..
Then we can truly say we are on the road to eliminating dino gunk as a worl fule...
..
Dave M.
Dataman19


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## PhantomPholly (Aug 20, 2008)

IamIan said:


> interesting video as well.
> 
> The noise issue during disengagement would need to be fixed as well.
> 
> http://www.magnomatics.com/Video.aspx


I don't think they mean for that to be a normal mode of operation. Rather, this is similar to the scenario I described earlier (a propeller striking something when the engine is running). The loud "ratcheting" noise you heard was the sound of the motor being disengaged from the load due to excessive torque - it's like a shear pin without anything actually breaking.

As a feature to protect the drive train from overtorque, the noise is actually perfectly acceptable (you should never hear it in "normal" use).


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## PhantomPholly (Aug 20, 2008)

dataman19 said:


> Excellent video....
> ..
> Now to apply this to EVs!
> Then to EPs (Electric Planes)..
> ...


Electric planes are further off than cars, because they need a lot more fuel (a typical "trip" of 3 hours in a small plane would consume between 24-100 gallons of fuel).

But, give us a gear reduction unit not prone to failure and which actually ISOLATES the prop from the engine harmonics, and suddenly we can reliably use automobile engines (around $4-6k) instead of aircraft engines ($24k and up).


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## Duncan (Dec 8, 2008)

Phantom,
Torsional analysis and drive-line design is old engineering
Why must $24K aircraft engines (most of which were designed by Noah's older brother) be used?

Can you not calculate the harmonics and avoid/redesign?


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## PhantomPholly (Aug 20, 2008)

Duncan said:


> Phantom,
> Torsional analysis and drive-line design is old engineering
> Why must $24K aircraft engines (most of which were designed by Noah's older brother) be used?
> 
> Can you not calculate the harmonics and avoid/redesign?


You would think so. Such does not seem to be the case. Note that I'm not a mechanical engineer by trade, so my comments are simply observations that "lots have tried, none have succeeded." In over 40 years of interest in aviation I can't tell you the number of announcements of, "Breakthrough engine for aircraft!" I have seen, yet almost none of them are still around. One rather famous one is Zoche in Germany. They had a demonstration engine decades ago, used to show up with a booth at airshows but haven't for over a decade, keep their web site alive but NOTHING HAPPENS.

Here is a link to the "alternative engine" section of the world's most active forum for experimental aircraft. Some people have success. Some do not. Some who have initial success have failures later, some must go through many failures before they obtain a reasonably reliable setup - and those generally end up with more weight / less power than a conventional aircraft engine.

The P-51 was a wonderful aircraft in WWII, but they NEVER solved the harmonics issues. They never ran for more than a few hundred hours before needing a re-build, and some did not make it until their scheduled engine change-out. The P-49 Aircobra was another innovative design using a drive shaft from the engine (behind the pilot) to the propeller (which had a hollow crankshaft to allow firing a 37mm cannon through the hub). Never worked well, at least not for long.

Theoretically many of these alternatives could have been "better," but for whatever reason it never seems to work in practice. Those that work end up heavier, more expensive, or both - and so like with most of the clever schemes for EVs are generally ignored because there is no real advantage.

I personally know one fellow nicknamed "Subaru Bob" who went through FIVE "unscheduled landings / engine changeouts trying to make a Subaru engine work. He flys with a Lycoming engine now.

But if YOU can make it work, I assure you you will become rich and famous!


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## _GonZo_ (Mar 23, 2009)

Winfield1990 said:


> This makes me remember a transmission idea I have a long time back not really related though.
> 
> But I stopped working on it for no reason just got tired of messing with it.
> 
> Was pretty sure that I was on to something also , I need to note it and go back to it sometime.


I use a paper notebok were I write or draw the "ideas" "inventons" that come out my mind now and then, so I can go back to them if necesary, as well I write or stick things that gave me inspiration, I find it ver usefull, and it is very nice to check all of them...


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## PhantomPholly (Aug 20, 2008)

I don't know - I only saw the article and the web site. They aren't divulging their secrets!


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## _GonZo_ (Mar 23, 2009)

Winfield1990 said:


> The design that the original post is about , Is the gearing adjustable while your driving.
> 
> they do say a very wide range of transmission gearing capabilities but is that based on being adjustable while your driving with no shifting?
> 
> They might have beat me to my design idea , if so .... if not then I still have a chance.


a CVT is that a contious variable transmision so there is no shifts it is like a continous ramp that in one side is low "gearing" and on the other high "gearing"
See picture.

It can work automatical or manually.

The bad thing of most CVT is that have big looses due friction...

I think that may be not dificult do achieve a high efficiency one with their sistem.


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