The torque's non existing influence on cutting speed.

[1wildthing]

The fish real makes a good example:

What would have more fish, a truck filled with a pan-fish caught with the real stuck in high-gear?

Or a truck full on lunkers, taken with the real stuck in low-gear?

Work is work, a conveyor running at 25mph with a bricks placed 1 foot apart, would pass bricks at the same rate as a conveyor running at 50mph with a brick every other foot, or 2 feet apart.

Yes, but it would take more horsepower to run the conveyor at 50mph with a brick every two feet because of the added friction and wind resistance needed to double the speed.

 

[Woodie]

The fish real makes a good example:

What would have more fish, a truck filled with a pan-fish caught with the real stuck in high-gear?

Or a truck full on lunkers, taken with the real stuck in low-gear?

It's like I always say, "Give a man a fish, and he eats for a day. TEACH a man to fish, and he eats for a lifetime. But then he wants a bassboat, and a 175 hp outboard, plus he's gonna need a depth finder, echo locator, GPS, a couple half-dozen rods and reels, a new truck to pull the boat..."

 

[ShoerFast]

Yes, but it would take more horsepower to run the conveyor at 50mph with a brick every two feet because of the added friction and wind resistance needed to double the speed.

Ya think?

How about we turn the bricks sideways on for 25mph conveyor, and run half the conveyor width on the 50mph belt?

Splitting frog-hairs is down the hall, to your left.

 

[PES+]

Rabbits are all cute and cuddly

so..................

 

[bwalker]

When people talk about a saw with alot of torque what they are reffering to is a saw with a nice wide HP curve.

 

[PES+]

oye............

 

[Sprig]

Most are in the ball park.

"Just the facts mam." (Joe Friday, Dragnet)

From the Columbia Electronic Encyclopedia:
Torque, in physics, that which tends to change the rate of rotation of a body; also called the moment moment, in physics and engineering, term designating the product of a quantity and a distance (or some power of the distance) to some point associated with that quantity. The most theoretically useful moments are moments of masses, areas, lines, and forces, including magnetic force.
Moment of force, commonly, a "push" or "pull," more properly defined in physics as a quantity that changes the motion, size, or shape of a body. Force is a vector quantity, having both magnitude and direction. The magnitude of a force is measured in units such as the pound, dyne , and newton , depending upon the system of measurement being used.
. The torque produced by rotating parts of an electric motor or internal-combustion engine is often used as a measure of its ability to do useful work. The magnitude of the torque acting on a body is equal to the product of the force acting on the body and the distance from its point of application to the axis around which the body is free to rotate. Only the component of the force lying in the plane of rotation and perpendicular to the radius from the axis of rotation to the point of application contributes to the torque. This radius is called the moment arm, or lever arm. The net torque acting on a body is always equal to the product of the body's moment of inertia about its axis of rotation and its observed angular acceleration acceleration, change in the velocity of a body with respect to time. Since velocity is a vector quantity, involving both magnitude and direction, acceleration is also a vector. In order to produce an acceleration, a force must be applied to the body. The magnitude of the force. If a body undergoes no angular acceleration, there is no net torque acting on it. Units of torque are units of force multiplied by units of distance, e.g., newton-meters, dyne-centimeters, and foot-pounds (or pound-feet).

For a simpler take on it from 'Howstuffworks.com'>

"Torque is a force that tends to rotate or turn things. You generate a torque any time you apply a force using a wrench. Tightening the lug nuts on your wheels is a good example. When you use a wrench, you apply a force to the handle. This force creates a torque on the lug nut, which tends to turn the lug nut.
English units of torque are pound-inches or pound-feet; the SI unit is the Newton-meter. Notice that the torque units contain a distance and a force. To calculate the torque, you just multiply the force by the distance from the center. In the case of the lug nuts, if the wrench is a foot long, and you put 200 pounds of force on it, you are generating 200 pound-feet of torque. If you use a 2-foot wrench, you only need to put 100 pounds of force on it to generate the same torque. "


So, in this light, a WildThingy will have the potential for more torque with a 32" bar than an 090 with an 16" bar when used to pry a groundies arse from a stump after lunch. :bang:

opcorn:

 

[RaisedByWolves]

When people talk about a saw with alot of torque what they are reffering to is a saw with a nice wide HP curve.

Yeah, that and lots of TORQ down in the bottom!



I think Sap moved to Sweeden!

 

[Luke]

Misc Ramblings

Bore/Stroke

Some of the latest thinking on this is that all things being equal and discounting losses due to friction(pistion speed in particular) Torque is not a function of stroke length, but of displacement. If piston speed and valve area is not is not a limiting factor, you will see alot of modern high perf and racing engines moving back towards smaller bores. Jon Kaase speaks and writes about this. Smaller bore equals shorter flame front, reduces opportunities for detonation, and can remove barries to rpm limitations. This is one of the biggest reasons you don't see true hemispherical combustion champers (entire bore diameter) anymore. Ever wonder why true Chrysler hemis and Boss Fords fell to the wedge motors in Pro Stock? At the end of Bob Glidden's Pro Stock dominance he learned that the Boss's long flame fronts and inefficient combustion were limiting his ability to turn the rpm of the wedge motors. Ford wouldn't adequately fund him to develop the wedge motors. He quit.

Rod Length - Smokey Yunick's writings on rod length dominated engine building for years - maximize piston dwell at TDC,,,,run the longest rod possible. Engine theory has come a long way since then. Modern heads can support the higher initial pistion velocities generated by short rods, and we have learned about the logrithmic effects of mass in motion and the importance of ring pack placements. I think this one will be argued for many more years since there are so many tradeoffs. I will never forget Buddy Morrisons (Reher and Morrison Racing Engines) reply to a question on the power effect of rod length ,,,"I think the connecting rod connects the piston to the crank"

 

[Marco]

you need hp and torque that is balanced to the job at hand, pretty simple really. Saw your breaker bar in half, just move it faster it'll be OK:biggrinbounce2:

 

[Crofter]

It all boils down to fitting the engine characteristis to the job at hand. Horse power per pound of engine increases with rpm. In a traction (bulldozer) engine weight is an assett and speeds are low; torque is king. In a chainsaw weight is a penalty and chain speed to a point an asset so horsepower at higher rpm is king. A stump cutter and a limbing saw can each benefit from a different torque / horsepower character. Ratio adjusters (transmissions) either gear up or gear down, have a cost and weight penalty. Use the engine that gives the most bang for the buck.

 

[Ekka]

Another great irony is that any engine will have equal torque and hp at 5250 rpm.

I just spend a while looking at the graphs and curves and it's true ... has to be coz hp is a calculated derivative of torque.

 

[Butch(OH)]

Wow, you'ens is smart. And to think I thought you was just a bunch of saw thugs, sorry

So let me see,,,if I get this right I need to take the motor out of my 660 and getta high speed diesel saw motor with long rods and short stroke, a low tranny with F-1 suspension anna 8 pin sprocket with 325 chain or I mightas well use an axe?

No darn wonder I can't get no wood cut,,
damn rip off artists at that STEAL dealer anyway

Once i get my new fangled high speed diesel saw goen what oil mix ratio would I use in it and should I change to a different bar oil?

 

[Big feller]

I just have to make a comment on this "torque issue" that I see in many many threads. Torque is a thing invented by car magazines that has totally overtaken peoples minds: Statements like: My car (or chainsaw like we discuss here ) performs so great because it has tons of torque... is totally BS IMO.



I take the point but...

The torque issue must be more important for chainsaws than cars as they have no gearbox. Peaky horsepower is fine whilst taking lots of small chippings with little loss of speed.

As soon as a saw bogs a bit it is the one with more torque that is likely to keep chugging and finish the cut.

Perhaps a few users of old beasts from the 80s might contrast using these against modern saws with similar HP.

Back to the cars - I have a car with an old Plymouth Fury engine. It has the same power to weight ratio as a Volkswagen Golf but weighs twice as much. On the flat they have similar performance, but when a steep hill comes along there is no contest. The bee in a tin is left for dust.

Maybe the torque thing is overused by the marketing Johnnies, but I'm not sure it should be dismissed as BS. Good topic for discussion though.

Big feller

 

[klickitatsacket]

if you have 2 saws with the same 6 HP. The first one turns at 5 RPM and the other at 40,000 RPM. The first one wouldn't hardly turn the chain until you fit it with a 200 pin sprocket and then it would never hold up against the tremendous forces put upon it. The second saw would screem but as soon as it touched the wood it wouuld fall on its' face if it even turned the chain at all.

 

[klickitatsacket]

it's about balance guys. RPM is important but not at the sacrifice of torque. A "torquier" motor will give you more options in tuning outside of the engine itself. You put larger sprockets on or longer bars, more cutters, lower rakers ect. If your engine is more toward RPM then all you have is one choice or smaller.

 

[SmokinDodge]

Wow, from chainsaws to Harleys to diesels and back. I just wanted to interject a thought I heard long ago from a bike builder.

"The only reason we have a transmission is because we don't have a good enough engine." I don't remember who said it but it has stuck with me.

 

[bwalker]

it's about balance guys. RPM is important but not at the sacrifice of torque. A "torquier" motor will give you more options in tuning outside of the engine itself. You put larger sprockets on or longer bars, more cutters, lower rakers ect. If your engine is more toward RPM then all you have is one choice or smaller.

Yep.

 

[chowdozer]

From a real world perspective as pertaining to bikes. A CR125 has pretty close to the same HP as my XR650L and the CR weighs almost 150 pounds less. The XR will spank a CR125 in a drag race from a standing start, and that's starting the XR in second gear. The XR will spank a CR125 from a rolling start, (provided you can keep the wheel on the ground). I have ridden both in tight woods. The CR takes lots of clutch work in tight to keep it in the power. The XR will lug to an idle and tractor through or over anything.

The CR is faster in tight woods, until the rider gets tired and gets caught out of the powerband of the motor. The XR is very forgiving with it's powerband. For rideability and grins per mile, the XR wins hands down. It's very satisfying to crack the throttle in any gear at almost any speed and have hold on tight acceleration. Now if they could do something about that porky 324 pounds.

Same with the saws. If it has a high and flat torque curve, it's going to be an easy saw to run. Like the 056 I got from Dean.

 

[Wes]

Wow. This is interesting. It is important to note that horsepower was NEVER intended to be the abtract concept that it is today. It was invented by a guy who leased steam engines to (I think) coal operations, and the fee was calculated at the number of horses replaced. A horsepower was (and is) the amount of coal a horse could move in a given amount of time.

Since horsepower is the amount of work done in a period of time, we should really be measuring chainsaw power in 'pounds of sawdust per minute' units, or 'inches of foot-across rounds cut per minute' and we would have a much more relevant, and no less 'contrived' unit of measure than the horsepower.

Please, no more comparisons between F1 cars and big trucks...