OEM lightened flywheel review

[keefer]

I had ProTec lighten my 61x style setup many years ago and it has held up fine. I seem to remember that they took off .5 pound. Definitely made a difference, a good mod for the $$.:biggthumpup:

 

[douglee25]

I was curious if the failure of the flywheel was due to machining on the face (front side) or the actual flywheel having an inbalance. I drew up a rough sketch of the flywheel in Solidworks and threw it into the finite element analysis program. I kept the hub as the restrained piece and loaded the flywheel (normal to the outer diameter). This would represent an inbalance to the flywheel while spinning.

Check out the results. The scale on the side goes from red to blue. Red signifies areas of high stress, while blue signifies areas of low stress. Look at where the levels are the highest? The area is right around the hub. That is identical to where the previous picture shows the failure.

Doug

 

[Jr.]

Doug, That is very intresting! Thank you!
It's giving me something to think about!!!!

 

[douglee25]

Doug, That is very intresting! Thank you!
It's giving me something to think about!!!!

Not a problem! :biggrin: What almost appears to me is that an inbalance would cause fatigue (bending back and forth) stress right at the hub causing a failure. I bet someone could simulate it with a flywheel coupled directly to an electric motor. If the flywheel was given an inbalance on purpose and just let go to spin until failure, I'd be curious to see what would happen.

Doug

 

[Flash-FX]

Douglee, That's really cool software!:hail: Can you model in the outside diameter and face taper cut then re-analyze?

I'm glad this doesn't happen to skis...:skull2: http://images.google.com/imgres?img...channel=s&rls=org.mozilla:en-US:official&sa=G

 

[Jr.]

Not a problem! :biggrin: What almost appears to me is that an inbalance would cause fatigue (bending back and forth) stress right at the hub causing a failure. I bet someone could simulate it with a flywheel coupled directly to an electric motor. If the flywheel was given an inbalance on purpose and just let go to spin until failure, I'd be curious to see what would happen.

Doug

In a perfect world, what you are saying is true, but think about what happens in a watercraft motor........
constant throttle change, which relates to constant rpm change. This is coupled to drastic acceleration & de-celeration in high compression, Modified motors.........
Now you also have pump loading & un-loading..............
Are you starting to see the severe service these flywheels are put thru?
So when modifing them, the key is to see how close you can get to the ragged edge, without crossing the line???
I do rebalance the flywheels after they are lightened. But that is only margionaly helpful when the mass strenth is removed. That is because of the differant harmonic frequencies are varied RPM levels.
I would be very intrested if you can do your test under varied conditions as I just stated. Then I would have a better Idea of exactly where the line is?
There use to be a product called the "Fluid Balancer". It was a PTO flywheel for the Rotax motors. Those flywheels had captured ball bearings in a groove running around the outer edges. When the motor was running, the balls would find the balance point at all rpm levels. Thus balancing the flywheel & making the motors last a good long time. It would be cool if it was possible in our motors?

ski ya, Paul

 

[douglee25]

In a perfect world, what you are saying is true, but think about what happens in a watercraft motor........
constant throttle change, which relates to constant rpm change. This is coupled to drastic acceleration & de-celeration in high compression, Modified motors.........
Now you also have pump loading & un-loading..............
Are you starting to see the severe service these flywheels are put thru?
So when modifing them, the key is to see how close you can get to the ragged edge, without crossing the line???
I do rebalance the flywheels after they are lightened. But that is only margionaly helpful when the mass strenth is removed. That is because of the differant harmonic frequencies are varied RPM levels.
I would be very intrested if you can do your test under varied conditions as I just stated. Then I would have a better Idea of exactly where the line is?
There use to be a product called the "Fluid Balancer". It was a PTO flywheel for the Rotax motors. Those flywheels had captured ball bearings in a groove running around the outer edges. When the motor was running, the balls would find the balance point at all rpm levels. Thus balancing the flywheel & making the motors last a good long time. It would be cool if it was possible in our motors?

ski ya, Paul

Good points Paul. This could be modeled one of two ways. Instead of an AC motor, one could use a DC motor with a trim pot. The problem with this is that whomever ran the test would physically have to vary the rpm until failure. Maybe if you set up procedure to do that about 4 times a day during your work hours. Otherwise the second way to do it is use a servo motor. This could be tied into a PLC (programmable logic control) with a program loaded into it. This program could contiue to loop forever. 8000 rpm, stop, 5000, 6000, 7000, etc. You could do anything you wanted. The problem with this setup is cost. Last time I priced out servo motors, each axis ran about $6000. That doesn't take into account software either.


Another thing that just dawned on me is using the DC motor idea with some sort of device to automatically vary the rpm. Maybe they have programmable pots?

Do you have a picture of the "Fluid Balancer"? Maybe something could be fabricated.?

Something to think about. Interesting stuff nontheless. :smile:


Doug

 

[douglee25]

Douglee, That's really cool software!:hail: Can you model in the outside diameter and face taper cut then re-analyze?

I'm glad this doesn't happen to skis...:skull2: http://images.google.com/imgres?img...channel=s&rls=org.mozilla:en-US:official&sa=G

I'm unsure of your explanation? I understand face taper cut, I'm unusure about modeling the outside diameter?

Doug

 

[Flash-FX]

I'm unsure of your explanation? I understand face taper cut, I'm unusure about modeling the outside diameter?

Doug

Ooops..sorry for the typo. What I was thinking was simulating the machined/tapered face and machined/reduced outside diameter of the flywheel.(where most guys remove weight) Just to see where it ends up, compared to stock...stresswise.

 

[Idok]

Lightened stocker here too (Paul) and it made a very nice noticeable difference.

It's roughly a 1/2 pond removed from the outer face/side.

I will never go back but I would go charging alum if they were like 200 new.

hey matt..whatever happeneed with you and Jetinetics?

I cracked the hub of my charging wheel, sent them an email and they said to send it in!

I rmember back awhile ago you were having tons of trouble just getting them on the phone....did you give up?

 

[w/rpm500]

I had an o/e done for the 500 by PROTEC... It had approx 1/2 lb removed ..some off the face,about 1/16th's thickness,thou not all the way to the hub,where the above tread shows its not a good area to cut... some off the outer edge... about 1/8 thick there.. the radius that was once there is gone... about $50.

 

[Exile]

Its a nice improvement,well noticeable.....but a stripped 2 flywheels stock in my freestyle ski that were lightened in a matter of minutes,maybe 7 or so.....dam physics! or just a bad job by the guys that smoked me for some cash!

Now goin with tl......beware the thin line!

 

[skysurfer2010]

i got my oem flywheel lightened by paul this past season. it was one of the best and cheapest mods i ever did! next year the blaster will get one too.

 

[blaster800]

I was curious if the failure of the flywheel was due to machining on the face (front side) or the actual flywheel having an inbalance. I drew up a rough sketch of the flywheel in Solidworks and threw it into the finite element analysis program. I kept the hub as the restrained piece and loaded the flywheel (normal to the outer diameter). This would represent an inbalance to the flywheel while spinning.

Check out the results. The scale on the side goes from red to blue. Red signifies areas of high stress, while blue signifies areas of low stress. Look at where the levels are the highest? The area is right around the hub. That is identical to where the previous picture shows the failure.

Doug

Im not at all qualified to chime in on this, but here goes , what would happen if you drill 2 more holes in the high stress areas ,would this even out the loads since the loads are in the non-hole areas ?? mabe try to run it through the program again with 2 more holes ! !

 

[douglee25]

Im not at all qualified to chime in on this, but here goes , what would happen if you drill 2 more holes in the high stress areas ,would this even out the loads since the loads are in the non-hole areas ?? mabe try to run it through the program again with 2 more holes ! !

I could do as you said, but I arbitrarily picked the load to be about 90 degrees to the holes that are in the face now. In real life, the inbalance could be anywhere on the circumference for that matter. The stress should be highest where inbalance is and 180 degrees around the circumference of the flywheel.

Doug

 

[robertg]

If lightening the stock flywheel makes that big of a difference, I wonder what the Riva flywheel will do? Before it cracks that is, and throws out my timing.

1.5 lb should make a big difference, however I am going to keep my stock lightened flywheel for backup.

 

[michael950]

I was going to have my flywheels lightened over the winter and just pulled the SJ, so I went to the blaster and found this. I take it this is lightened, and about all that should be removed.

 

[MADMAT]

hey matt..whatever happeneed with you and Jetinetics?

I cracked the hub of my charging wheel, sent them an email and they said to send it in!

I rmember back awhile ago you were having tons of trouble just getting them on the phone....did you give up?

I think I ordered one on their site or something and they said it would be a few months and I said thats cool. I called them from month 4 to month 12 (!!!!) before just cancelling the order. They assured me I was first on the list a couple of times but I just lost interest after a while.

I would still like to have some type of steel hubbed alum charger someday but only if it is fairly priced and easily avaliable. Lightened stocker till then.

Hey waterdawg!!! How about a charging 701 flywheel!!!!:woot:

 

[MADMAT]

I was going to have my flywheels lightened over the winter and just pulled the SJ, so I went to the blaster and found this. I take it this is lightened, and about all that should be removed.

I don't know what that is but it doesn't look right at all.:bigeyes:

 

[MADMAT]

If lightening the stock flywheel makes that big of a difference, I wonder what the Riva flywheel will do? Before it cracks that is, and throws out my timing.

1.5 lb should make a big difference, however I am going to keep my stock lightened flywheel for backup.

That thing is gonna hit hard believe me!