066 Poly vs Metal

[Lakeside53]

Buy him a dual port muffer front and then do the test again..

 

[wagonwheeler]

I don't get how the 'spooling up' has anything to do with torque in the cut...does anyone actually measure acceleration time out of the wood?

I mean I know a 346 spools up quicker than a Super Wiz 66, but how much diff does it make on an 066 w/ metal or poly and does it matter?

Holding RPM in the cut I can certainly see as being important.

..

 

[Lakeside53]

I can see it being and advantage in saw that has a narrow(ed) power band... but..

Anyhow.. has anyone actually weighed the two flywheels? The poly has a laminated steel core... The mass being distributed though 360 degrees instead of a pair of major counter balances as in the aluminum design.

 

[RiverRat2]

havin fun

Buy him a dual port muffer front and then do the test again..

I know Lake I was just kidding, with him and setting him upopcorn: , it was just funny cause he was pickin on me about my saw that Dean built out of used parts that really looked rough when I first got it.... but it has a fresh top end,& I installed a dual port muffler, And I ve been tuning and testing for two weeks and sharpening the chain and it really looks like a sleeper but screams. parts of it are still painted black,,, and his saw rides around in his truck all day now he does keep the chain sharp and he runs 87 octane @ 40:1 mix and no telling how old it was,,,,, remember I repeated what Dean said for the sake of stopping argument "assuming All things where equal"

Funny you said that he asked me when I could fix his muffler like that, and I told him l'' do it this winter,,,,, And after I install his muffler I'll finish my Woods port mod on my saw and well do it all over again


LOL

 

[Freakingstang]

Man I love it when Yall use those big words like Trailerhouse and Watermelon :hmm3grin2orange: All kidding aside, so if im understanding this correctly it just comon sense that a lighter /well balanced roatating assembly with a poly flywheel should "Spool up Quicker" thus increasing torque in proportion with the rise of the RPM??????? over a saw with a metal flywheel,,,,,, assuming that all things other wise are equal......

So since my WHS buildup 066 with my dual port muffler Mildly Modded that has a metal fly wheel and mortally stomped a hole in my buds newer ms660 (Poly flywheel) as we cut cookies today off the same 24" fresh pine log... I let him cut with it and he was very impressed as he had bucked out the tree earlier in the day with his saw... I wish I had had my video cam to get his eyes buggin out....
Thanks Dean,,,,,

Im Lovin it :biggrinbounce2:

Dude, too many smilies...


My 660 revs faster than the my 066, but the 066 carries more R's in the cut. The poly flwywheel will allow it to rev quicker, but the aluminum one will keep the revs up instead of dropping like the poly does. The 660 is also easier to bog than the 066 RL was.

 

[Lakeside53]

Dude, too many smilies...


My 660 revs faster than the my 066, but the 066 carries more R's in the cut. The poly flwywheel will allow it to rev quicker, but the aluminum one will keep the revs up instead of dropping like the poly does. The 660 is also easier to bog than the 066 RL was.

You sure it's just the flywheel? The energy stored in the flywheel is dissipated quickly and small in comparision to that required to cut. Remove the finger from the throttle while in a big cut and see how long the flywheel keeps you cutting.

Even better - punch in the decomp (if you have one); then it's only flywheel and no fighting of compression (less anyhow).

 

[RiverRat2]

Are you using the same fuel, wood, bar, and chain and just swapping powerheads to make your comparision????? just wondering cause I have a Poly late model Saw Im building and I will probably mod it similarly

 

[Freakingstang]

Are you using the same fuel, wood, bar, and chain and just swapping powerheads to make your comparision????? just wondering cause I have a Poly late model Saw Im building and I will probably mod it similarly

When they were both stock, yes. I even switch topends because the newer ones are less aggresive (cylinder wise) as the older ones.

Same kinda deal with cars... I tried an aluminum flywheel in my 350 hp motor. On slicks launching at 5K, the same setup as with the steel flywheel, would bog on the launch. The steel made the car launch hard. once the aluminum finally came back into the powerband, it reved quicker, but the iniatial loss of mementum caused the car to slow too much.

Net loss/gain...cost me 500 bucks to figure out that the aluminum flywheel cost me time almost a half of second. No other changes were made.

Fast forward three years. Differant engine, differant car. Same bodystyle, but more HP motor. Launching the car with the steel flywheel, resulted in massive wheelspin on slicks and breaking traction between shifts. Aluminum flywheel made the launch more user friendly and reved quicker between shifts while maintaining traction.

Result this time was in favor of the aluminum flywheel. lost about .2 tenths for just a flywheel change.

in smaller wood the poly should be quicker, but in bigger wood the aluminum should take the cake, at least that has been my experience. Both good saws, though

 

[bwalker]

The flywheel is just like a capacitor in that it is a storage device. Changing flywheel weights will not do squat to the output, but can change the operating charachteristics.

 

[RiverRat2]

I can see it being and advantage in saw that has a narrow(ed) power band... but..

Anyhow.. has anyone actually weighed the two flywheels? The poly has a laminated steel core... The mass being distributed though 360 degrees instead of a pair of major counter balances as in the aluminum design.

have you ever weighed them Lake or do you know off hand if there is much difference???? and with respect to the matter of the larger saw with the broader powerband it should not be as much of an issue, Right???

 

[Kneejerk Bombas]

Spun weight creates a gyroscopic effect that makes it hard to throw around.
It also slows throttle response.
I have to agree with Lake that the momentum of the extra weight is little to nothing compared to the drag of the chain. I suppose if you reved it up and slammed the bar into he wood too hard, it might give you some extra go for a 1/4 of a second. But then it'll take that extra 1/4 of a second to get it back up.

 

[klickitatsacket]

take a 2 066's one with a metal fly wheel and one with out and the put the same top end on both. The metal flywheel will give add an additional 1,400 RPM to the torque band.

For those of you who are speculating... stop and run a test before you start handing out information. As for the weight... great argument that leaves half of the information out of the equation. Where is the weight? is it in the center or out at the ends of the diameter. The distribution of the in the flywheel makes a big difference in how it works.

 

[Lakeside53]

Are you sure the ignition timing is the same?

Another variable is you can't just take the flywheel alone - it's the combination of all the rotating masses, and the two 066 being discussed have different cranks.

 

[timberwolf]

I would think there may be a difference there, just moving the wheel a degree or two could account for the change dean is illuding to. That amounts to a few thousandths of an inch movement in the keyway.

Where the weight is in the fly wheel does make a difference in it's inertia, but that still make no difference in steady state torque or HP.

 

[ShoerFast]

I would think there may be a difference there, just moving the wheel a degree or two could account for the change dean is illuding to. That amounts to a few thousandths of an inch movement in the keyway.

Where the weight is in the fly wheel does make a difference in it's inertia, but that still make no difference in steady state torque or HP.

Were the weight is, or "arm" has as much to do with it as how much weight. Figure-skaters show the characteristics for the best visual.

A saw engine would only need a fly-wheel effect at the low end, some lawnmowers will not start with out a blade, but will continue to run if it sheds a blade running.

To me, it seems that the nature of saw-chain in a cut has more to do with the engine speed then anything, if you have ever put a tach. to an engine while it is in a cut you would See what I mean, it is all over the place, and having a quicker recovery or re-acceleration with a poly flywheel would seem better then trying to reduce de-acceleration with more weight.

 

[timberwolf]

Were the weight is, or "arm" has as much to do with it as how much weight.

Is that not just what I said?

And I have noticed the difference in RPM going between a race chain and stock chain, shaving the weight makes a difference.

However a chain that goes in one direction turns 180 deg and goes in the other more resembles reciprocating motion than circular. For that reason many accelerated forces in a chain are lost as opposed to a fly wheel where the accelerated forces are conserved (centripetial motion)

The outside surface of an 066 flywheel gets going close to 300 mph. how much fin area and the angles of the fins would be a factor to think about as well.

 

[ShoerFast]

Is that not just what I said?

And I have noticed the difference in RPM going between a race chain and stock chain, shaving the weight makes a difference.

However a chain that goes in one direction turns 180 deg and goes in the other more resembles reciprocating motion than circular. For that reason many accelerated forces in a chain are lost as opposed to a fly wheel where the accelerated forces are conserved (centripetial motion)

Yes, that is what you said, I hoped to add the term "arm" for it.

What I think slows a chain the most is that there essentially trying to stop and start or change "bite" constantly. The way a cutter rocks back of it's heel and alternates chip removal gives the advantage in re-acceleration to a lighter chain, at give or take 65MPH and the weight of a chain, there is not much kinetic energy stored in the weight of the chain. Nor is there much stored in a fly-wheel, if you consider that a saw will reach it's slowest speed in the thickest part of the wood, and recoup that speed as it is passing into the thinner wood.

It would be my guess that if you charted the speed of saw in a blocking cut, that the speed fallows more how much wood it is cutting, as it would only take a couple of inches to dissipate the fly-wheel effect. There is a good chance that if you matched the to and bottom speeds of the saw , for a say, say while cutting a 4" path at the top, my bet would be that it's a little faster as it passed cutting 4" at the bottom, as the saw would be running hotter at the bottom.

For me, I like a slightly aggressive chain, as it works better for me to hold a saw slightly out of a cut then force one into a cut, it is easy to get a little too much saw into the cut that way, but I think having recovery is better then inertia.

 

[timberwolf]

Ok, we were on the same page.

From the racing aspect the idea is to keep the saw at the RPM which procuces most power, then hit the wood at the top to use up that flywheel & crank energy, back off on the pressure as the saw comes down into the in the in the wood RPM, then continue to back off as the wood gets bigger. After mid point start to push a bit more. The if it is a change over hit the wood again and do the same thing. On the last cut, the saw can almost be bogged to use up stored energy (very much a timing thing)

That is for round wood, cutting square cants is another story.

Letting the saw load down or rev up would be loosing time as it would be off peak power.

I did do some thinking on the energy loss in the chain just to make it go arround the bar, from what i figgured it could be upwards of .5 hp on 3/8 chain.

 

[hautions11]

Poly Vs metal

Dean,

Would you advise against putting one of the new big bore kits on one of the older metal flywheel saws?

 

[klickitatsacket]

Big bore is fine. It would be less than modifying a stock cylinder. Modifying the big bore on a metal flywheel crank.... we'll just have to see how she holds up. I have an 066 with a metal flywheel and as soon as my prototype big bore gets here I will be putting it through it's paces.