Changing the weigh of the flywheel?

[czar800]

There's a ton of discussions about the top end of any giving saw i.e. Pistons, squish, ports, compression, and so on. Which got me thinking about the flywheel. I did search and found some older Post and debate back-and-forth between reputable members about The effects of flywheel has on any given motor.
My real question is is anyone changing the weight on saws either adding weight or removing weight?

My only experience with flywheel weights are on dirt bikes.

 

[blsnelling]

372XP. I made this but have never tried it. I would consider this for race only use.

 

[Big Block]

interesting

 

[Mastermind]

A lighter flywheel allows the engine to spool up quicker.....a good thing in a cold start race maybe.

A heavier flywheel will help the engine maintain rpm in the cut.

Depending on what you want, determines whether or not you would prefer a lighter, or heavier flywheel.

 

[Trx250r180]

This ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 

[czar800]

A lighter flywheel allows the engine to spool up quicker.....a good thing in a cold start race maybe.



A heavier flywheel will help the engine maintain rpm in the cut.

Depending on what you want, determines whether or not you would prefer a lighter, or heavier flywheel.

I'm very wet behind the ears/newbie when it comes to Modifying a chainsaws. I find flywheel weight very interesting and also how far away from center the weight is located. Question......two flywheels the exact same weight overall. one the weight is moved away from the center the other the weight closer to the center. Wouldn't you think the flywheel with the weight moved away from Center spool slower?

 

[czar800]

Feel free to take me to school!

 

[czar800]

My thought process is finding the right overall weight and weight distribution on the flywheel.

 

[blsnelling]

Saws do their work at WOT. I see little if any gain in a mod like this on a work saw.

 

[czar800]

Saws do their work at WOT. I see little if any gain in a mod like this on a work saw.

I understand so the benefit would be to add weight to a flywheel of a work saw?

 

[maico490]

A heavier flywheel will help the engine maintain rpm in the cut.

In most things I bow to the Masters superior knowledge but in this case a saw with a heavier flywheel will only hold a higher rpm for the fraction of a second that it takes to use up the extra stored energy. After that both saws will be equal.
However in all other respects you are invariably right.

 

[drf255]

A heavier one should give a saw a slight edge from the max rpm piss rev into the cut for the first small period of time. Stored kinetic energy.

Like a heavier flywheel on a car. Better launch.

 

[Mastermind]

In most things I bow to the Masters superior knowledge but in this case a saw with a heavier flywheel will only hold a higher rpm for the fraction of a second that it takes to use up the extra stored energy. After that both saws will be equal.
However in all other respects you are invariably right.

I'd say you are spot on.

I was merely thinking of it as added inertia. More inertia means it's gonna be harder to stop once moving.

 

[HiOctane]

I'm very wet behind the ears/newbie when it comes to Modifying a chainsaws. I find flywheel weight very interesting and also how far away from center the weight is located. Question......two flywheels the exact same weight overall. one the weight is moved away from the center the other the weight closer to the center. Wouldn't you think the flywheel with the weight moved away from Center spool slower?

The closer to center help easier handling the saw side to side .

 

[czar800]

Other than a complete hot saw most leave the flywheel untouched?

 

[czar800]

When I think of flywheels and the weight of a flywheel. I always recall going to the steam shows and seeing relatively low horsepower steam tractors belt pulley outworking modern much higher Hp tractors PTOs.

 

[spencerpaving]

It takes hp to pump cooling air....especially at high rpm....on race saw all or most of the fins are removed

 

[jmssaws]

The fins are still on my 064 flywheel but that's about it, can't recall how much lighter it is but it's a bunch, 034 or 046 clutch will loose some weight also. I didn't notice a power difference but it made it very snappy. I done that years ago and never have done another, I'd like to try a stock flywheel for comparison but I can't find one.

 

[czar800]

I thought this explained flywheel function well.

http://www.w8ji.com/rotating_mass_acceleration.htm


.

 

[czar800]

1. Weight distance from the center line is very important, because it determines the weight's circular velocity (speed)! Stored energy goes up by the SQUARE of the radius change. If we replace a 4-inch diameter hollow driveshaft with an 8-inch diameter tube of exactly the same weight, it is not just double. It is twice the size squared, or four times the stored energy when it weighs the same!
2. The faster we spin the weight, the more energy it stores. If we double RPM, we multiply stored energy four times. Again it is a square of the change, just like weight distance from centerline is a square.