POLL: Is Torque Important?

[Sled Puller]

Just remember if somethings moving call it horsepower.

So... if a Dana 80 yoke gets twisted off, call it________?



Back to the original question, is torque important?

 

[rbattelle]

Just to be factual...

You cannot express work as torque. Work is horsepower.

Strictly speaking, work is definetly not horsepower. Work is work and horsepower is rate of work. Work is a physical manifestation of energy (energy is defined as a capacity to do work).



Speaking of work, here's an example that will blow your mind. Let's say you pick up a 100 lb block. In the act of picking it up you have applied a force whose action resulted in a displacement: you did work. Now let's say you hold that block level and run a mile at constant speed. On that 1 mile run you did NO WORK ON THE BLOCK. You applied a force to it to overcome gravity, but since your force only countered gravity and resulted in no displacement, you did no work. As long as your speed is constant, you also did no work by moving that block for a mile.



Now at the end of that mile you are tired so you put the block down. Well, the act of putting the block down is negative work, so the net work you've done on that block is ZERO. Yes, you just picked up a 100 lb block, ran a mile with it, and put it back down and you did NO work on it.



Wild, isn't it? For those with a mathematical background, all this is because work is defined as a vector dot product of a force and a displacement. Of course, the Cosine of 90 degrees is 0, hence any displacements perpendicular to the force application result in 0 work. The "constant speed" requirement ensures the person in the example is not applying any parallel force to keep the block moving during the run... technically the person should also be in a vacuum, but that's really nitpicking.



-Ryan

P. S. Yes, I have too much time on my hands.

 

[GIT-R-DONE]

Strictly speaking, work is definetly not horsepower. Work is work and horsepower is rate of work. Work is a physical manifestation of energy (energy is defined as a capacity to do work).



Speaking of work, here's an example that will blow your mind. Let's say you pick up a 100 lb block. In the act of picking it up you have applied a force whose action resulted in a displacement: you did work. Now let's say you hold that block level and run a mile at constant speed. On that 1 mile run you did NO WORK ON THE BLOCK. You applied a force to it to overcome gravity, but since your force only countered gravity and resulted in no displacement, you did no work. As long as your speed is constant, you also did no work by moving that block for a mile.



Now at the end of that mile you are tired so you put the block down. Well, the act of putting the block down is negative work, so the net work you've done on that block is ZERO. Yes, you just picked up a 100 lb block, ran a mile with it, and put it back down and you did NO work on it.



Wild, isn't it? For those with a mathematical background, all this is because work is defined as a vector dot product of a force and a displacement. Of course, the Cosine of 90 degrees is 0, hence any displacements perpendicular to the force application result in 0 work. The "constant speed" requirement ensures the person in the example is not applying any parallel force to keep the block moving during the run... technically the person should also be in a vacuum, but that's really nitpicking.



-Ryan

P. S. Yes, I have too much time on my hands.

You forgot the discclaimer: Pleaase dont try this at home..... :-laf :-laf

 

[KYLE4]

Torque is where it is at think about it formula one cars high reving light weight race cars they redline around 13,000 plus rpm's all horsepower Heavy truck needs torque to get them moving Just a like a heavy 70's muscle car with a 5,000 rpm big block to get them rolling.

 

[Chrisw]

My thoughts on Torque

Torque



And to think all this time I thought it was a feeling I had when something didn’t go my way.



Like when the guy on the cell phone almost run me off the road, That really Torque’s me off.



You know what I saying :-laf

 

[R-N-R]

Must be Torque... . I've never heard anybody say "That really HP's me off!".

 

[Crowhurst]

I'll humbly offer a non-technical illustration of the distinction between torque and horse power:

1. Torque. Two women are arm wrestling on a bar. (Oh, is it just in England..... ?). The women have equal arm lengths, and their arms are vertical and still, and locked together at the hands. The two women try their hardest, and the one whose arm starts to move forward has applied the greater torque. (horizontal force at hand multiplied by arm length)



2. Horse power. Two women, of equal weight, run up a hill, starting side by side. To avoid differing wind resistance because of different clothing, they are naked. (The climate is very mild in England. ) At the end of a time period, let's say one minute, the women stop. The one that is in the lead has been developing the greater horsepower. ( Horsepower= rate of doing work. Work done= weight multiplied by vertical height gain)



My wife and her sister have been of great help in my understanding of the basic concepts of engineering. Nick.

 

[SBall]

Best explanation!

Crowhurst,

In all my years of engineering and mechanics I've never heard a better real-life explanation of torque vs. horsepower. Forget all those dizzy equations! Your examples say it all!

Steve

 

[rbattelle]

My wife and her sister have been of great help in my understanding of the basic concepts of engineering. Nick.

By running uphill naked? :-laf



-Ryan

 

[Kennywould]

Get a ticket for doin that around here!!!!

 

[Big_Daddy_T]

Torque breaks stuff. Horsepower is how fast you were accelerating when you broke it.

 

[Big_Daddy_T]

Thanks for setting me straight rbattelle. The rate of work. Not work. The faster you can do work. Either the more torque you have. Or the more rpms. Is there an equivalent for energy when discussing an engine(notice I didnt say motor). Cause I can convert watts to hp. Or its capacity to do work.

A good friend of mine explained the vectors and tangents to me. When explaining work.



Work harder. Work faster. LOL. Stupid comercial.

 

[jetenginedoctor]

Strictly speaking, work is definetly not horsepower. Work is work and horsepower is rate of work. Work is a physical manifestation of energy (energy is defined as a capacity to do work).

True.

Speaking of work, here's an example that will blow your mind. Let's say you pick up a 100 lb block. In the act of picking it up you have applied a force whose action resulted in a displacement: you did work.

True.

Now let's say you hold that block level and run a mile at constant speed. On that 1 mile run you did NO WORK ON THE BLOCK.

False.



It took force to accelerate the block from a standstill to whatever speed you can run a mile at. That's like saying that an engine that's got to accelerate your truck from a standstill to ???? MPH at the end of a quarter mile doesn't have to do any work, becuse it's not being used to lift the truck off the ground at the same time. Your statement is incorrect.

You applied a force to it to overcome gravity, but since your force only countered gravity and resulted in no displacement, you did no work.

False.



Due to the way your body is 'designed,' you cannot walk or run without doing work, even in a zero-gravity environment. Adding the weight of the block to your body weight means your body has to work that much harder to run that distance. This is also work. . . . muscle fatigue doesn't come from thinking harder.

As long as your speed is constant, you also did no work by moving that block for a mile.

The only way that you could maintain a body in motion without imparting any force/work is if it is moving unimpeded in a total vacuum, completely unimpeded and uninfluenced by gravitational or other natural forces or modes of resistance. Example: If you had a rail car that had zero frictional losses and ran it on a totally flat piece of track with no end, as soon as you quit driving it with a motive force, it will begin to decellerate untill all its inertia is overcome by aerodynamic drag. Though it's tough to measure, you will do work carrying a 100 lb block for a mile, running or otherwise.

Now at the end of that mile you are tired so you put the block down. Well, the act of putting the block down is negative work, so the net work you've done on that block is ZERO.

Wrong.



There is no such thing as negative work. Lowering a 100lb block to the ground requires only slightly less work than picking it up. The difference is in the rate at which you picked it up, and the rate at which you lower it back to the ground.

Yes, you just picked up a 100 lb block, ran a mile with it, and put it back down and you did NO work on it.

Go ask a physics teacher.

Wild, isn't it?

Wild? Sure is! So wild that it's almost completely wrong.

For those with a mathematical background, all this is because work is defined as a vector dot product of a force and a displacement.

Clearly you have no mathmatical background.

Of course, the Cosine of 90 degrees is 0, hence any displacements perpendicular to the force application result in 0 work.

I have a belly button.

The "constant speed" requirement ensures the person in the example is not applying any parallel force to keep the block moving during the run... technically the person should also be in a vacuum, but that's really nitpicking.

It was your example. The fact that your example was completely incorrect and impractical makes me wonder if it was worth you posting, or more importantly, me taking the time to rebut it.

-Ryan

P. S. Yes, I have too much time on my hands.

Then use some of that time to study the physics books that you clearly learned nothing from.

 

[Big_Daddy_T]

Holy smokes. Im usually a little more tactful.

 

[rbattelle]

Jet Engine Doctor-



Ouch. That hurt.



I have only one question: without knowing me, how did you know that I have no math or physics background?



-Ryan

 

[jetenginedoctor]

Holy smokes. Im usually a little more tactful.

And I usually make sure I know what I'm talking about before I post something as an absolute.



Go ahead and ask a physics teacher if you don't believe me, or go grab another engineer and see what he/she will tell you. It's not a matter of having a fancy schmancy engineering degree as somebody earlier suggested, its a matter of a very fundamental undersatnding of the laws of physics.

 

[jetenginedoctor]

Jet Engine Doctor-



Ouch. That hurt.



I have only one question: without knowing me, how did you know that I have no math or physics background?



-Ryan

By reading your explaination of work over time, that's how. It's crystal clear that you THINK you know what you're talking about, but refuse to listen whe people with a legitimate education try to explain how things really work. I wouldn't poke my head into ANY of this except Sleddy keeps talking crap and calling me into things. I realize that I can't MAKE you guys learn something, but this whole misunderstanding you have in the relationship of engine torque versus horsepower is bad enough to make me embarrassed to admit I drive a diesel truck. If you want to debate the issue, lets go. A much faster resolution to the issue is if everyone who doubts what I'm saying to find a UNIVERSITY Physics professor and show them a copy of these threads.

 

[jetenginedoctor]

Hmm interesting discussion. Every dyno I have been around measures TORQUE, and HP is a number that comes from the amount of torque at a given rpm by a mathmatical EQUATION! I will admit that every dyno I have been around is some kind of brake dyno that loads the engine. None of the accelerate like mad for a little while measurement.

Hi Michael,



You're right about load dynos measuring torque. In the case of an engine dyno, it's measuring torque produced by the engine at the crankshaft. In the case of a load bearing chassis dyno, it's torque measured at the roller shaft. That's part of the formula, we can agree. . . . right? The other thing the dyno measures is RPM. RPM gives us both the speed and the time aspects of the HP formula. In the case of the engine dyno, it's measuring crankshaft RPM, which allows us to calculate the engine's crankshaft HP. Still with me? Good! In the case of the load bearing chassis dyno, the speed of the roller is measured, allowing the direct calculation of HP at the rollers. Still with me? HP at the rollers is engine HP minus inertial and frictional losses within the drivetrain, tires, etc. Thus, HP measured at the roller (road HP or wheel HP, etc) is always less than crankshaft HP.

As far as *I* am concerned torque is everything.

Okay. Would it be safe to state that another way??? Consider instead of saying "torque is everything," substitute "tractive effort is everything. " What am I talking about? Okay, consider this. . . . . Tractive effort is the result of the engine's torque, the effective gear ratio as a result of both the transmission and axle gearing, and the diameter of the drive wheel. When you graph torque and tractive effort, you find that they follow the EXACT same shape, as tractive effort is in direct proportion to engine torque.



In a nutshell, tractive effort is what accelerates your truck, pulls a sled, or makes the truck climb a grade with that big camper/backhoe/cabin cruiser in tow. It IS the force that makes the truck move by its own power.

Without it all you have is a bunch of rpms.

RPMs -- If you have RPM, you have something spinning about a centered axis, right? If this something is made of any material with mass, this spinning something is storing some amount of energy. When either an accelerating or decellerating force is applied, you are either adding or subtracting from the energy of that spinning object. Thus, if you use an engine to spin a flywheel from 0 to 3000 RPM, then de-coupled the two, the flywheel would spin without being driven by the engine. . . . agreed? If you applied a braking force to that flywheel, you would release the energy applied to it that was applied by the engine that accelerated it, minus frictional and aerodynamic losses as the flywheel turn. If you measure the change in the flywheel's speed over a period of time both accelerating and decelerating, you can calculate the rate at which energy was applied or removed from that spinning mass. Still with me? Does this sound familiar? Sure it does, I've just described an inertia dynamometer.



Do some looking into the gas turbine engines used in aircraft, armored tanks, ships, etc. You'll find that the engines make a great deal of HP, but little shaft torque. These machines utilize geartrain systems to reduce the shaft RPM and multiply torque to make the power usable. It's the same as how the power company uses transformers to go from the 500kV on those tall high-tension power lines to the 120V and 240V outlets in your home. . . .

The more rpms, the less fuel ecomony.

In the same exact engine, yes. This is due to both friction and the energy that is lost to accelerating and decellerating a very heavy piston and connecting rod in these engines. I agree with you completely.

Torque is what is applied to the transmission that twists the shafts. Work around farm tractors, torque is what is doing everything.

Cool, another farmer! Torque does twist the shafts, this is true. However, if torque is being applied to the axles but the wheels aren't turning, fields aren't getting worked. As soon as the torque is enough to make the tractor and implement move, work is being done, and there is (by definition) HP exerted.

Hp is the number used to sell cars, trucks, engines, tractors.

Yes. So is torque, MPG, warranty length, APR, etc.

As far as the ford, chivvey, and dodge pulling loads, the factor is which truck is working at the right rpm. Hell a huge torque building engine won't pull for crap if it has way too much gear or is working against the governor all day. Pulling the hills is a package deal, get the whole package working together and you can pass everybody.

Yes. An engine with a broad powerband is preferred in a tow vehicle as you don't have to resort to shifting gears all the time to keep the engine at a speed where it produces an adaquate amount of power to keep the load moving, climb a grade, etc.

What everybody forgets when going down the road is aerodynamic losses. The amount of power that is needed to move the truck through the air. A peterbuilt with dual air cleaners, tall stacks, flat top sleeper, stretch frame pulling a tall reefer will take a BUNCH more power to pull through the air. That guy in the T2000 with full fairings, tight to the trailer can keep up with that pretty pete with alot less motor.



Michael-flame suit is on.

Yes again. It takes X-amount of force to overcome the aerodynamic drag, tire rolling resistance, etc for a given speed on a flat road. The less drag, the less force must be applied. The less force needed, the less HP/TQ needed from the engine. The less HP/TQ needed from the engine, the less fuel burned. . . . so on and so forth. We're on the same page here, I think.

 

[rbattelle]

By reading your explaination of work over time, that's how. It's crystal clear that you THINK you know what you're talking about, but refuse to listen whe people with a legitimate education try to explain how things really work.

I must have offended you for you to be so critical, and for that I sincerely apologize. In the interest of everyone else's education, could you please explain why there is no such thing as negative work?



To anyone else I offended, I also apologize. My intent was simply educational.



Jetenginedoctor taught me a valuable lesson today, and for that I am indebted.



-Ryan

P. S. Just for the record, I pulled the example I posted from "Fundamentals of Physics" volume 1 (a textbook), except that in the text it was a cat rather than a "block".

 

[jetenginedoctor]

I must have offended you for you to be so critical, and for that I sincerely apologize. In the interest of everyone else's education, could you please explain why there is no such thing as negative work?

Offend? Nah, not really. Irritate, yes. It's a pet peeve of mine, people spreading their own misunderstanding of how things work on the internet. So forgive me if I in any way offend YOU, but I feel compelled to set things straight.



Now, with regards to negative work. In order for there to be something that could be called negative work, there would have to be something as negative time, negative distance, or negative force, right? To the best of my knowlege, time only goes one way, so scratch negative time. Negative distance? A negative distance is only relative to your point of reference. A negative distance described in one direction is a positive distance when described from the opposite direction, so that won't work either. Negative work? Do you mean work undone? How can you undo work? Can you spin an engine and make air and fuel go back into the atmosphere and fuel tank? Do you mean work done in the opposite direction? All you've changed in that case is the direction, but you're still applying a POSITIVE force. Explain YOUR take on "negative work. "

To anyone else I offended, I also apologize. My intent was simply educational.

Make sure you know what you're talking about before you try to educate people with it.

Jetenginedoctor taught me a valuable lesson today, and for that I am indebted.



-Ryan

Nice adult reply. Not even a hint of sarcasm, very mature.

P. S. Just for the record, I pulled the example I posted from "Fundamentals of Physics" volume 1 (a textbook), except that in the text it was a cat rather than a "block".

So you won't mind scanning and posting the page from which you got this info? I'd be interested in seeing who the author, publisher, and press date of that book is as well.