Thread: chain weight

Might be in left field here, but I don't think that chain inertia is very significant in terms of keeping the chain speed constant or to prevent bogging, here is why

the inertia is far greater from of all other parts that are rotating at 12000 rpm (the crank, clutch, sprockets, piston, conecting rod, fly wheel....) Noted: Piston only provides momentary inertia during stroke.

If inertia added performance, they would not be trimming fly wheel weights to bare minimum, and maybe thay would even add tiny lead weights to the chains, or better yet even tungsten.
Is this is why carbide chains are better? LOL

Take a 5 lb brick and tie it to a rope, them swing it above your head in a circle til your tired, then take a 10 lb brick and do the same thing, your tired much quicker as more effort is exerted.

TW

Yeah, you're right Crofter, I just wanted to patronize Gypo, my mentor. Yes, I agree that the radial acceleration of the chain will be a nonzero quantity due to differing radiuses, but I still suspect that it's effect on different mass chains would be a rather weak second order one.

But both of those bricks are gonna hit ya in the head.

Sure, like I suggested earlier, Art Martin only removes mass from his chains to save postage not horsepower! And I am just stirring the pot, Timberwolf started this mess just to see if he could get you squabbling,

Frank

I suspect the flywheel has much more affect than the chain. Rotational inertia once set in motion would be use full, but with all the friction and two turnarounds; I wouldn't think the chain inertia would add or detract significantly. But, the racers ought to already know the answere from experiences.

Where are KD and Dennis on this?

I'm no chainsaw expert, but to me the weight will make very little if any difference, because your still dragging the chain through the wood. Irregardless if the chain is heavy or light the amount of tension (or pull) on the chain from cutting, is far greater than that little bit of weight.
It takes alot of energy to accelerate an object in comparrison to the amount it takes to maintain speed. If you were to go WOT with your saw with either heavy or light chain I bet the WOT RPM would be pretty much the same. That little chain is no match for a 2 stroke of that power. In fact that may be a good way to check the power loss of a heavy chain if you have a tach for your saw. Take the light chain and measure the RPM with a cut and free spinning and quickly swap the chain and measure the RPM again.

Mac tools has a cool little tach that measures rpms 2-stroke/4-stroke, 1cyl up to12 cyl that you just have to put beside the coil.
Pretty cool toy to have, I'm tempted to get one myself, but then I fix cars for a living.

Just my 5 cents worth

Since the introduction of my "synthetic" bar oil, friction is
no longer a factor. The bar also runs so cool that the stellite
becomes superconductive, and with the field generated by the
motion of the flywheel, the chain never actually touches the
bar. It's just another theory I am working on. I am trying to
integrate it into Fish's Unified Field Theory, but am having a
rough time with the math involved, all of this beer has fogged
my thinking.
Walt Galer is whipping out the racing chains for my prototype
model, which shall challenge the giants of the saw world.

Hey Fish, I was wondering how long you planned on holding out about your new MAG-LEV cutting attachments. With the :exclusive rights for distribution" agreement that you have worked out with Poulan, it should put them back in the game. Russ

Poulan, sheesh, they would just paint it Orange and call it
Husqvarna. They also have a group of lawyers that are
concerned about mixing liquid nitrogen and synthetic bar oil,
too much red tape. I will try the Koreans that bought out
McCulloch, they seem a little more receptive to my radical
innovations.

I like the 5# vs 10# brick on a rope theory. Unortunately, there isn't as much difference between two brands of chain as there is between the bricks. At the "ends" of the "rotating" mass, energy still must be sacrificed to change direction of the chain components, but the amounts involved are small, and the differences between them are smaller yet. While the difference might be calculable, would it be measurable?

I believed that the folks who doctor up chains for racing do so to optimize cutting and chip flow. Some racers use 1/2" chisel chain if they can get it, when lighter chain with more and smaller cutters is certainly more available. There must be more advantages than just the added strength of the chain...

wieght and inertia are relative, thats a given thanks to Newton. In racing I would think that to increase cutting performance, you would have to reduce friction on the cutting surface ie. grinding it down as small as possible, that would have greater efect than reducing weight. The boot analgy is the perfect example, weight drives inertia, and inertia maintains relative motion to an extent. The only variable in this total equasion is friction in the cutting surface, because the rest are given, weight, inertia,bar friction, travel, so only cutting friction is left as the only real changeable variable.

Granted the mass of the chain likely only makes a small difference, so does a lot of other aspects like; polishing the ports, filing the gulets, thining the botom side of the top plated, using synthetic oil, filing back the tooth, replacing the choke plate with a primer, upgrading the air filter, various engine tweeks, ect ect ect........ 1% here 2% there. Many of the improvements are cumulative and even coumpouding to each other, and many are win-win with no apparent, relevent or unacceptable draw backs.

Building a winning race car is not just about building the best engine, it is considdering and maximizing all available potentials.
Don't forget many of the best consumer sports cars were developed for the race track. Speaking of race cars, why would they even considder using aluminum and magnesium wheels, drive lines and engine components if there was not an advantage in reducing rotational weight.

As long as the engine and drive components are strong enough and have enough momentum to get the piston/s back up to TDC, enything more is just weight.

Sure it is only 10% more chain weight, but that make the diference between the power head of the saw moving 25 tons and 22.5 tons an hour.

Timberwolf

I think with the amount of contact that the chain has on the bar
and making a full 180 degree turn twice, makes the inertia
thought not realistic. On a circular saw, more like the analogies
introduced earlier, it is an entirely different scenario. Turn a
chainsaw of while at full rpms, then a circular saw, then the stop
times are dramatically different. On a chainsaw, the friction
is a constant drag on the system, even as cutting fibre is
moreso. If a given engine cutting the same fibre, with the
same chain, except for reduced weight on the sidestraps and/or
drivelinks on one, the lighter one would cut faster, as the engine
requires less energy to run the lighter chain. Introducing too
many variables just makes it confusing. But I think inertia is a
tangeant that has little merit.
In everyday cutting, chain weight is not worth thinking about.
In racing, I would suggest that the lighter weight chain, with
the same cutters, would cut faster. Common sense would dictate
that, I would think.

Fun _Chopper
You are slightly confused about what inertia and momentum are. I thought you would see in the ridiculous analogy of the heavy rubber boots that the energy lost to drive the boots up and down has very little to do with their simple inertia and momentum in the linear plane. With any thing as crude as the contours of saw chain drive tangs and the respective sprockets, there is nothing like the effortless exchange of energy in sine wave motion. It doesn't all come back. Look at Timberwolfs original post; look at the number of foot pounds of energy involved. With heavier components it takes proportionately more centripetal force to overcome the added centrifugal force.This must be applied from end to end across the arc of the bar top and bottom in purely sliding friction. The additional weight is not inconsequential!! This is not purely rotary motion like a round flywheel. If this were the case , I would agree with more of what you are saying.

Frank

I am saying that weight has nothing to do with anything..thats my point, and to support that point I sated that a light chain has less inertia, and better acceleration.A heavy chain has more inertia and slower acceleration. The counteracting forces slow the effects of inertia. The bottom line here is what does cain weight have to do with anything, in a car you move the entire machine, therefore weight does matter. On a chainsaw you move the chain, and since all things are relative except for the friction induced by the cut, the only factor left for a chain is the reduction of friction in the wood by reducing the surface area of the cutting surafces. Your analogy was dead on more power was lost during acceleration, but as you approached a constant speed, the momentum you created in the boots caused an energy drop off meaning you expended less energy to keep the boots going at a constant speed, whereas with tennins shoes you wouls have to expend a constant amount of energy to maintain a constant speed. This is inertia..so tell me again what does chain weight have to do with anything?