The torque's non existing influence on cutting speed.

[ShoerFast]

Just for a think, what would the VE be of an engine with a perfict "V" stack, and pipe?

 

[Lakeside53]

If I may ask, what is a "non aspirated" engine?

He means Asprin-rated - the operator

 

[Canyon Angler]

Power is a RATE. It is the ability to do a certain amount of work IN A CERTAIN AMOUNT OF TIME. Mathematically, power is measured in [units of work] divided by [units of time] and it is expressed in units such as horsepower, watts, BTUs per hour, tons of ice per hour, etc etc etc. No matter what, time is a necessary element of power.

POWER = WORK/TIME = ENERGY/TIME = [FORCE]x[DISTANCE]/TIME = [TORQUE]x[NUMBER OF REVOLUTIONS]/[TIME]

If you multiply power by time, then, algebraically, the time units "cancel out" and you're left with units of energy or work such as a BTU or a calorie or a kilowatt-hour or [the heat of fusion of a ton of ice.].

Starting at the bottom, we have Force. Force is measured in things like pounds or Newtons. A force is just a "pushing" impulse. Torque is akin to force in the sense that it's a twisting rather than a pushing impulse. A torque of 8 foot-pounds is the FORCE you get when you put 8 pounds on a one-foot-long lever arm, or one pound on an 8-foot-long lever arm. It's a force.

OK, if you apply that force over a DISTANCE, then you have done WORK. If you turned a rusted bolt 10 revolutions against a resistance of 8 foot-pounds, that would be a given amount of WORK or ENERGY...exactly half as much work or energy as you would have done by turning the same rusted bolt 20 revolutions.

OK, if you wanted to talk about POWER, you would need to add the dimension of TIME and say that a particular motor had enough power to turn that rusted bolt X revolutions IN Y MINUTES. A machine that was turning that rusted bolt against that 8 foot-pounds of resistance at a speed of 10 revolutions PER MINUTE would be said to be putting out twice as much POWER as a machine that was turning the same bolt at 5 rpm.

Aren't we done with this thread yet?

:deadhorse: :deadhorse: :deadhorse: :deadhorse: :deadhorse: :deadhorse: :deadhorse:

 

[Canyon Angler]

If I may ask, what is a "non aspirated" engine?

One that has too much CHOKE! :hmm3grin2orange:

 

[klickitatsacket]

Sooner or later, you will reach the highest efficiency RPM. Here's a brain teaser. The rpm of highest VE by definition is also Peak Torque RPM, using the mathematic definition. It probably is also the most efficient for mileage, if you ignore a bunch of stuff like friction.

anyway, now that we have hit peak VE, why spin it higher? becuase horsepower is torque times RPM, and if we can keep our VE somewhat reasonable, and just spin it faster, we get "free" horsepower. So going a little further, the old time engine builders are after VE over a wide rpm range. Which by the way is NOT trivial to do.

Your RPM to gain the best VE for a particular saw is easily set with the H screw and a log. When doing this you usually end up a little rich and is great for cooling the engine down. When set for VE you also will have plenty of room to lean it out and gain RPM (and HP) if smaller wood is a steady diet for your saw.

This is great for cutting big wood, using long bars, more cutters or milling.
What happens if you are limbing then all that torque is meaningless.

You can not have one with out the other but you also need balance.

 

[04ultra]

If I may ask, what is a "non aspirated" engine?

One that is not running .


.

 

[ShoerFast]

One that is not running .


.

Hay, I have a couple of those!

 

[Canyon Angler]

One that is not running .


.

...and non-running engines have notoriously low torque! :jester:

 

[klickitatsacket]

...and non-running engines have notoriously low torque! :jester:

unless it is a steam engine

 

[timberwolf]

Imagine a steam chainsaw with a woodfired boiler. Be beach to run in hot weather but you wouldnt have to pay exttra for hand warmers and carb heat systems.

 

[Tzed250]

pushBANG

Deisels? You want to talk about Deisels? Go check the results of this years running of the Grand Prix of Endurance and Efficiency(otherwise known as the 24 hours of le Mans). The compression ignition engine Audi ruled the day!

 

[Woodie]

interesting thread.

a few fallacies presented. One factoid was that horsepower was a derived measurement, and dynos measure torque and calculate horsepower.
Actually, almost all modern dynos measure horsepower, and calculate torque. As an example, look at ANY of the chassis or wheel dynos where you drive your mustang on and strap it down, and accelerate a drum. they are measuring the acceleration of the drum, which measures horsepower. if they know the rpm of the engine, they then calculate torque. Look it up.

I did:

http://en.wikipedia.org/wiki/Dynamometer

I was right.

 

[Woodie]

Torque by its mathematical definition is pretty much useless to about everything.

You, ummm....you're not serious about that, are you? Honestly? The "mathematical definition" is useless? I wasn't aware of that. I'll forget all my physics training now...since it's useless. All these years I carried it around, too...and for naught.

i used to fight this battle, eventually figured out my mathematics and physics definitions of torque aren't really what the old timers are talking about.

Mighty presumptuous of you, wouldn't you say? If you go back and read most of these replies, you find them pretty much spot-on where it comes to the relationships between force, power, and work.

 

[drmiller100]

You, ummm....you're not serious about that, are you? Honestly? The "mathematical definition" is useless? I wasn't aware of that. I'll forget all my physics training now...since it's useless. All these years I carried it around, too...and for naught.



Mighty presumptuous of you, wouldn't you say? If you go back and read most of these replies, you find them pretty much spot-on where it comes to the relationships between force, power, and work.

yup, pretty much useless. degrees are neat for , well, hmmm.


doug "degrees in math,fizzicks, cs, and business."

 

[Ekka]

HP=TORQUE * RPM / 5252

http://auto.howstuffworks.com/horsepower.htm

http://auto.howstuffworks.com/question622.htm

http://en.wikipedia.org/wiki/Horsepower#Mechanical_horsepower

Dont forget these links

 

[boatermark]

I think "non aspirated" was meant to mean "normally aspirated" or an engine that draws in air by itself opposed to an engine fitted with a turbo unit.

Now, if we want to start at the basics, we should probably start with units of time, mass, and distance. I am pretty sure you can't get calculate power, work, torque, moments, force, acceleration, etc. without starting with these.

This thread seems to be missing something...

 

[ShoerFast]

I think "non aspirated" was meant to mean "normally aspirated" or an engine that draws in air by itself opposed to an engine fitted with a turbo unit.

Now, if we want to start at the basics, we should probably start with units of time, mass, and distance. I am pretty sure you can't get calculate power, work, torque, moments, force, acceleration, etc. without starting with these.

This thread seems to be missing something...

Boatermark

Good post! welcome to the site!

There is a chance that most knew what was meant by the term non-aspirated engines, but all in the name of fun, it is the atmosphere that pushes air into an engine, to fill the void caused by the engine, not the engine drawing it in.

As for the thread missing something, there is a chance that those that still don't understand what HP is, and "T's" effect on it, never will understand it?

 

[Drive_1305]

Suppose an engine has its Tmax (maximum torque) at say 9,000 rpm. Now apply more load and slow the engine to 6,000 rpm, hold things steady, and it produces T6 torque which going by torque curves will be less than Tmax. Why is T6 less than Tmax? Is it because at the higher rpm its drawing in more fuel creating a more powerful power stroke? Or do I need to look at the power strokes over time and say theres more strokes at the higher rpm so it adds up to more torque?

Now decrease the load, let the rpms go to 11,000, and hold things steady. Now the engine produces T11 which will again be less than Tmax. Why is it less? Is it because the engine is turning faster and this leaves the 2 stroke"valve" open a shorter amount of time, therefore less fuel can be drawn in and this creates a weaker power stroke?

Suppose my reasoning is correct for T11. At 6,000 rpm wouldn't the 2 stroke "valve" stay open longer and allow more fuel to be drawn in- creating a more powerful stroke?

Im a little fuzzy on what happens and exactly why.

 

[drmiller100]

Drive,

you've pretty much got it figured out. go too fast, and there isn't enough time for the ports to flow enough air to get a full charge.

go too slow, and the harmonics and inertias of the charge won't quite be perfect, you will get more exhaust dillution, and less torque.

peak torque is somewhat interesting. peak horsepower means more chips flying however.

Want to know an EASY way to increase your torque??? put a smaller drive wheel on.

 

[RiverRat2]

Hey Miller,

interesting thread.

a few fallacies presented. One factoid was that horsepower was a derived measurement, and dynos measure torque and calculate horsepower.
Actually, almost all modern dynos measure horsepower, and calculate torque. As an example, look at ANY of the chassis or wheel dynos where you drive your mustang on and strap it down, and accelerate a drum. they are measuring the acceleration of the drum, which measures horsepower. if they know the rpm of the engine, they then calculate torque. Look it up.

I just want to know one thing Why does it have to be a Mustang???????,,,,,,,,,,,,,,,,,,, Did Freakinstang put you up to this?????????????