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CDMA
06-04-2002, 11:17 PM
Well in school I am actually learning some cool stuff you guys would love and I have to put some posts together about it but for now I got a kick out of one of the less usefull things I learned...

Power is torque multiplied by engine speed to produce a measurement of the engine’s ability to do work over a given period of time. In the 17th century, steam engine inventor James Watt sought a way to equate the work his steam engine could perform to the number of horses required to perform the same task. Watt performed simple tests with a horse as it operated a gear driven mine pump by pulling a lever connected to the pump. He determined that the horse was capable of traveling 181 feet per minute with 180 pounds of pulling force. This multiplied to out to 32,580 pounds-feet per minute which Watt rounded off to 33,000 pounds-feet per minute. Divided by 60 seconds, this yields 550 pounds-feet per second which became the standard for one horsepower. Thus horsepower is a measure of force in pounds against a distance in feet for a time period of one minute.

Chris

Sorry I am approaching 20 hours straight at the desk...this stinks

Formula Jr
06-05-2002, 01:07 AM
The whole HP thingy is a joke. Why do we even still use it? Its just torque, or Watts or Calories. I'll bet Toona has a theory on Calories........ :D

Scott Pearson
06-05-2002, 06:00 AM
Owen,
It still sounds cool as hell....There is nothing like saying..."Yup its pushing 3,000 Horse Power, But I think I can get a little more by twiking it a bit.

(NJ)Scott

AVickers
06-05-2002, 09:58 AM
Why do they say pounds-feet instead of foot-pounds?

Over the years I've noticed a change in this terminology... When James W. and I were in HS Physics together the term was foot-pounds.

BTW: Horsepower is important as a description of the ability to do work over time -- not just to apply a force in an instant. Think of a really tough guy -- lots of strength (torque)-- but no endurance (power). Maybe good at arm wrestling, but can't make it through three plays as a linebacker... The concepts are both useful and complimentary.

Forrest
06-05-2002, 10:03 AM
James Watt? Everyone knows that Big Grizzly invented horsepower.

McGary911
06-05-2002, 06:18 PM
If I remember correctly, HP is basically a function of torque. Something like Torque X RPM / 5250 = HP

Torque is in lb-ft or ft-lbs if you like, and 5250 is a mathmatical constant. It starts to make sense when you plot the 2 curves against each other. I'm certainly a bit foggy on the thing, but I think thats it...If I'm wrong, someone with some education give me some learnin'....

McGary

Rootsy
06-05-2002, 06:19 PM
on the water it's all about torque! horsepower being a rate of torque as stated earlier, and only having merits really in drag and circle track racing where acceleration counts. actually in drag racing mph is determined by HP... in a boating situation the amount of HP you are making matters little, look at the torque curve instead. it takes a certain amount of torque to spin a certain prop a certain rpm at a given slip for a given hull of a given drag. once your torque peak begins to drop off and you reach that torque number you will gain no more rpm. if your hp curve begins to peak or level off as you reach that torque number (your torque peak will generally always peak and begin to fall off before your hp curve due to the increasing rpm) your rpm rate of change will begin to slow down as you approach your max rpm that the motor can develop with your certain combination and you will slowly creep toward that WOT rpm.

ok mr smarty pants chris! you may be able to educate us on all kinds of neato stuff but can you answer me this....

how much wood would a woodchuck chuck if a woodchuck could chuck wood??? huh huh? :D :D :D

GEOO
06-05-2002, 07:50 PM
Chris, I thought it came from large cubic inches, High CR, Big cams, Superchargering and good fuel source. :) GEOO

Formula Jr
06-05-2002, 08:09 PM
If you've ever been on an actual steam engine powered paddle wheeler the HP thingy starts to make no sense. Here you got a 100 foot, heavy wood ship, that takes about 30 seconds to go from dead stop to 7 knots. All on about 50 HP. Increadable torque at ultra low RPM. Put a 50 Merc on the back @ wot, and you would never even know it was there.

But you're right Scott, say'en, "Shes pump'in 16,500,000 foot/lbs per minute." Isn't as cool as 500 Horse Power.... or is it? :D

And Chris you might recheck the history here. Watt based it on a horse's ability to pull up loads of coal. Thats what the Lbs (Stones) figure is in there for....17th century? tisk, tisk, tisk,.what are they teaching you guys.......Every red blooded American Knows Robert Fulton invented the Steam Engine. Don't put any stock in that Limey propaganda.

-----------------
Dividing anything with PI -except PI, is just plain irrational. :D

PaulO
06-06-2002, 08:55 AM
From a practicality point of view torque is key to boat performance because in the real world we cannot experience torque without horsepower or vise-versa. In scientific terms however, torque is meaningless as far as any application concerned with speed. Torque is a measurement of twisting force only without time as a consideration. When you torque a head bolt there is no measurement of the time it takes to reach that level of "tightness". Horsepower includes time to achieve an amount of work as a factor. Speed is always measured in regard to time. Torque can be increased by mechanically altering gear ratios and therfore a less powerful engine can move, lift, carry greater loads as long as you don't mind the increase in time it takes to do it. Increase the length of that breaker bar you are using on those head bolts and you are increasing the torque applied. In applications where time is a factor (such as boat or car speed) horsepower is the real gauge.
PaulO

Steven Cohn
06-06-2002, 02:32 PM
Steven Hawking needs to get on board with this one.

Formula Jr
06-06-2002, 04:44 PM
Mr. Hawking is having trouble with his ISP. Seems they still use 300 baud modems and C-64s in Heaven. :D

I propose we introduce some new scientific nomenclature.

George Desmond's X-18 = 1 Geoo Unit.

This makes things very easy to explain.

My Boat is 1/3 a Geoo Unit. Where as the Space Shuttle is 200,000 Geoo Units. :D