What is Horsepower?

[peter399]

horsepower is work over time.

I can lift 10,000 pounds a foot off the ground. It takes me about a day.

A 1000 horsepower engine can do that well under a second.

Horsepower can be converted into acceleration. Get a G meter gizmo that plugs into your cigarette lighter, type in the weight, and it can tell you the horsepower of the engine.

Hook up an inertial dyno to a car and it can directly measure horsepower. Hook up the RPM signal and it can COMPUTE torque.

Horsepower causes acceleration, or it can be converted to heat, or it can be converted into changing a solid log into little chips.

The term "torque" in the real world is a parody of the mechanical definition of torque. Torque in the real world really means a wide, flat horsepower curve that is very usable. It isn't finicky.

If you have a 7 pin sprocket, and want to increase your effective torque, just convert to a 6 pin sprocket.

You will cut wood a lot slower, but your "torque" will increase.

Well said. Excellent. Brilliant!

 

[Woodie]

Torque in this discussion is just derived from power and rpm.

To anyone with even the most basic understanding of physics, that sentence is conclusive proof that you don't know what you're talking about.

That being said, anything more on my part is casting pearls before swine.

 

[peter399]

To anyone with even the most basic understanding of physics, that sentence is conclusive proof that you don't know what you're talking about.

That being said, anything more on my part is casting pearls before swine.

Oh Woodie, woodie, woodie ....

Try to see a big black box containing an engine in front of you. You have no idea what it looks like inside (for example if it has gearbox). Out of the box comes a shaft. Now what can you do?

Question one: Can you say anything about the so called torque of the engine by doing any measurements?

Question two: Can you say anything by the power of the engine by doing any measurements?

 

[belgian]

Maybe they did...there are certainly fewer posts, so far, in this thread.

But notice how most of them think you are wrong?

While there are many people in the current thread who have it correct, Chowdozer explains it in terms even you should understand.

With all do respect Woody, imo Chowdozer doesn't understand either.

so it appears we cannot get a unanimous understanding on this topic, I recommend we keep our own individual opinion. Next time you visit your dealer to buy a new saw, you certainly specify you want a torquey one and forget about the hp. Them manufacterers are all wrong you know, they must be using engineers to develop those saws ...

 

[WRW]

Well said. Excellent. Brilliant!

Think so?

"Horsepower can be converted into acceleration. Get a G meter gizmo that plugs into your cigarette lighter, type in the weight, and it can tell you the horsepower of the engine."


Are you sure that is not the HP at the rear wheels?


"Hook up an inertial dyno to a car and it can directly measure horsepower. Hook up the RPM signal and it can COMPUTE torque."


That direct measurement...does it measure some rotational mass and it's rpm?


"Horsepower causes acceleration, or it can be converted to heat, or it can be converted into changing a solid log into little chips.


The term "torque" in the real world is a parody of the mechanical definition of torque. Torque in the real world really means a wide, flat horsepower curve that is very usable. It isn't finicky."


You use a torque wrench to measure head bolt tightness or a horsepower wrench?


"If you have a 7 pin sprocket, and want to increase your effective torque, just convert to a 6 pin sprocket.

You will cut wood a lot slower, but your "torque" will increase."


When you change the "gearing" you change the rpm of the chain...plug that into the equation.

 

[sperho]

I find it interesting that there is so much debate in a thread that deals with a topic that is entirely undebatable. Good troll, Simonizer.

Of course, the fact that some can communicate more effectively than others about technical matters plays a role in the confusion as well. opcorn:

 

[Woodie]

Next time you visit your dealer to buy a new saw, you certainly specify you want a torquey one and forget about the hp.

No, that goes to what one of the other posters was talking about...the misuse of the term torque. I would never say that. I would, however, say something like "Give me a saw that produces a large amount of torque along a wide RPM band."

Nah, I wouldn't even say that...I would probably just say "Give me one a'them new 346s."

Them manufacterers are all wrong you know, they must be using engineers to develop those saws ...

Yup, they sure do. But it's the marketers that are selling it using peak HP numbers.

 

[Woodie]

You use a torque wrench to measure head bolt tightness or a horsepower wrench?

It just don't get any better than that.

 

[peter399]

It just don't get any better than that.

That doesn't have anything to do with what we are discussing. With your wrench you apply a torque to the bolt by a lever and a force. They rotate together with the same speed. Hence the torque applied on the bolt by the wrench is the same as the torque applied on the wrench by the bolt.
This is however not true for combustion engines since you have gearboxes, flywheels etc. There you you can't say anything about the torque applied by the piston on the crank shaft without complete info about the whole system.
An enormous force on the piston won't help you if you don't have rpm's. Small force on piston, high rpm and a gear box will do the same thing - > What we refer to as engine torque" is of less interest.

What matters is what comes out (hp) of your black box.

 

[fuzzle]

That doesn't have anything to do with what we are discussing. With your wrench you apply a torque to the bolt by a lever and a force. They rotate together with the same speed. Hence the torque applied on the bolt by the wrench is the same as the torque applied on the wrench by the bolt.
This is however not true for combustion engines since you have gearboxes, flywheels etc. There you you can't say anything about the torque applied by the piston on the crank shaft without complete info about the whole system.
An enormous force on the piston won't help you if you don't have rpm's. Small force on piston, high rpm and a gear box will do the same thing - > What we refer to as engine torque" is of less interest.

What matters is what comes out (hp) of your black box.

What is the definition of horsepower Peter? The definition as James Watt defined it?

 

[spacemule]

I can't believe you all are still arguing about this.

 

[fuzzle]

I can't believe you all are still arguing about this.

Hahaha! Yes, some people seem to be trying to redefine horsepower. :deadhorse:

 

[WRW]

That doesn't have anything to do with what we are discussing. With your wrench you apply a torque to the bolt by a lever and a force. They rotate together with the same speed. Hence the torque applied on the bolt by the wrench is the same as the torque applied on the wrench by the bolt.
This is however not true for combustion engines since you have gearboxes, flywheels etc. There you you can't say anything about the torque applied by the piston on the crank shaft without complete info about the whole system.
An enormous force on the piston won't help you if you don't have rpm's. Small force on piston, high rpm and a gear box will do the same thing - > What we refer to as engine torque" is of less interest.

What matters is what comes out (hp) of your black box.

Are you saying that the engine's output shaft can not have a measureable torque value? Or a transmission output shaft? Or a gear shaft? Or...nevermind.

 

[WRW]

Oh, what the hey. If there is no torque value for the final drive, then how do they compute the horsepower that you want.

 

[peter399]

Are you saying that the engine's output shaft can not have a measureable torque value? Or a transmission output shaft? Or a gear shaft? Or...nevermind.

No, that's not what I said. And I won't say again what I have already said.
Let's leave everyone with their opinions like you said Belgian and let them live happy

 

[Al Smith]

I can't believe you all are still arguing about this.

Good old Simon has the uncanny abilty to bring out debate in the multitudes.

Whom ever's [plural] is behind this on-line alter ego has studied the subject of human behavior.Most of the info this guy generates is factual but the self proclaimed genius does slip up every now and again.That's where the fun begins.

Rather than take this seriously,sit back and enjoy the amusement value of the whole scenario .

 

[hokiebob1]

This is ridiculous

 

[ShoerFast]

That doesn't have anything to do with what we are discussing. With your wrench you apply a torque to the bolt by a lever and a force. They rotate together with the same speed. Hence the torque applied on the bolt by the wrench is the same as the torque applied on the wrench by the bolt.
This is however not true for combustion engines since you have gearboxes, flywheels etc. There you you can't say anything about the torque applied by the piston on the crank shaft without complete info about the whole system.
An enormous force on the piston won't help you if you don't have rpm's. Small force on piston, high rpm and a gear box will do the same thing - > What we refer to as engine torque" is of less interest.

What matters is what comes out (hp) of your black box.

If taking the TQ-wrench idea out of the discussion helps prove your point, why do we seem to sweat more TQing the last say 1/8 of a turn then say the first 2 inches of a bolt?

The friction of a bolt is measuring the "Brake-horsepower" needed to TQ the bolt. Unless you have actualy ran the TQ on a few dozen "Torque to Yield " bolts, you would not understand the concept.

 

[belgian]

Let's leave everyone with their opinions like you said Belgian and let them live happy

Glad you got the message. I only got upset about the fact that engineers were the ones to blame here

Got a question for ya : If you swedes go bragging about your swedish blonds, do you talk about their power of love or their torque of love ? :hmm3grin2orange: :hmm3grin2orange:

 

[WRW]

Got a question for ya : If you swedes go bragging about your swedish blonds, do you talk about their power of love or their torque of love ? :hmm3grin2orange: :hmm3grin2orange:

LOL! I'd take some of that torque of love, but I got a rusted shaft!