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Leroy

When is a horse a horse?

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Leroy
Is there simple method to determine what they are selling today, is, as rated? The picture i have is 27 beasts each one haveing the ability to pull a car. hooking 26 of them up to the ouput shaft of a 27 horse engine. In a tug of war the horses should loose. while in reality the engine would be torn from it mounting attempting to reel those horses in. Ok maybe thats not the right picture. Torque * RPM /5252 = Horsepower If we can measure a load, not a slipping load because a slipping load will tell up slip not true output. How do you determine how much torque you have? How do you determine how many horses on an engine without a lable telling you?

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Leroy
quote:
Originally posted by JoeJ
Leroy, ;)Try this thread, maybe it has what your looking for. [url]http://machinebuilders.net/wwforum/forum_posts.asp?TID=379&KW=hp+rating&PN=0&TPN=1[/url] Joe
Yep it helped. Now i know im not a lonely boggled mind.

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JoeJ
;)Yup, good info and real nice projects going on. :DLeroy, generally they get me more confused than I already am:D. But then someone will draw me a picture or send a PM to explain it in common terms:D. Joe

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WiscTom
Hitchin up a team of horses is not going to get you there. First off, one horse does not one horsepower make. It is claimed that James Watt used horses and bricks and a coal mine to arrive at his definition of horsepower. But, he did not define the term to match what a real horse could actually do. He could have used house rats in a treadmill for all that matters. It just happened that he had a horse and a coal mine shaft handy at the time. For him, it was merely a reproduceable motive force. Second, since there is a bona fide need for "useable" horsepower for use in comparing engine specs. Several bodies have taken it upon themselves to rate the motors we commonly encounter. A horsepower is still a horsepower. Yet, the definitions for test conditions vary across the industries. Electrical motor horsepower is tested in a very different load state than internal combustion engines, for example. Think that through a bit. An electric motor can put out a huge wallop of horse power under heavy load. Yet if loaded this way it will burn out in ten minutes. Does this mean that the 6hp electic motor in your shop vac will out pull the 6 hp gas engine in your lawn tractor? Not a chance in France. The electric motor will put up a very short fight, start to smell, and go phhht. The same goes with gas engines. You aren't likely to see an engine used twice in a Nascar race. The definately put out the Hp. Yet, they are completely shot in 500 miles. Back to your question. For small engines the folks at SAE test those engines under load in controlled situations, and report back to the manufacturer on what HP it found. This makes it fair for everybody. For larger ag engines, say on tractors. The folks at the Univ of Neb have been testing whole tractors under controlled conditions for decades. Thus tractor Hp is what they can actually do all day long. Again, a fair test for all. They report thier findings back on both drawbar, and PTO Hp to the maufacturer. This partly explains why hitching up a 40 Hp farm tractor to your small pickup truck will always result in the pickup going backwards(the rest has to do with gearing, traction and such.) Horsepower is Horsepower. Your definition is accurate. Bear in mind that for the benefit of the consumer, engine testing is different for different sorts of motors. An outboard motor does not see the same conditions in real use as a vacuum cleaner, nor does a hydraulic motor, a pickup truck, or a big John Deere. As a result, they do not do so in the test lab either. The real issue of confusion is how the nameplate ratings come to be.

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Leroy
quote:
Originally posted by WiscTom
Hitchin up a team of horses is not going to get you there. First off, one horse does not one horsepower make. It is claimed that James Watt used horses and bricks and a coal mine to arrive at his definition of horsepower. But, he did not define the term to match what a real horse could actually do. He could have used house rats in a treadmill for all that matters. It just happened that he had a horse and a coal mine shaft handy at the time. For him, it was merely a reproduceable motive force. Second, since there is a bona fide need for "useable" horsepower for use in comparing engine specs. Several bodies have taken it upon themselves to rate the motors we commonly encounter. A horsepower is still a horsepower. Yet, the definitions for test conditions vary across the industries. Electrical motor horsepower is tested in a very different load state than internal combustion engines, for example. Think that through a bit. An electric motor can put out a huge wallop of horse power under heavy load. Yet if loaded this way it will burn out in ten minutes. Does this mean that the 6hp electic motor in your shop vac will out pull the 6 hp gas engine in your lawn tractor? Not a chance in France. The electric motor will put up a very short fight, start to smell, and go phhht. The same goes with gas engines. You aren't likely to see an engine used twice in a Nascar race. The definately put out the Hp. Yet, they are completely shot in 500 miles. Back to your question. For small engines the folks at SAE test those engines under load in controlled situations, and report back to the manufacturer on what HP it found. This makes it fair for everybody. For larger ag engines, say on tractors. The folks at the Univ of Neb have been testing whole tractors under controlled conditions for decades. Thus tractor Hp is what they can actually do all day long. Again, a fair test for all. They report thier findings back on both drawbar, and PTO Hp to the maufacturer. This partly explains why hitching up a 40 Hp farm tractor to your small pickup truck will always result in the pickup going backwards(the rest has to do with gearing, traction and such.) Horsepower is Horsepower. Your definition is accurate. Bear in mind that for the benefit of the consumer, engine testing is different for different sorts of motors. An outboard motor does not see the same conditions in real use as a vacuum cleaner, nor does a hydraulic motor, a pickup truck, or a big John Deere. As a result, they do not do so in the test lab either. The real issue of confusion is how the nameplate ratings come to be.
WiscTom I had to gasp several times. The statement that one horse does not a horsepower make. <<<< Catching my breath>>>>. Then the one that followed, he did not define the term to match what a real horse could actually do.<<<<Catching my breath again>>>>. I'm learning all the time and im not armed well enough to argue the points. If the tax man hears that One actual Horse is capeable of three horses. Those who raise horses will go broke. Well maybe not. But could you expand on the explaining, of those two comments. Many have said that the Engines built today do not accurately desribe the horse power because their old 16 horse can out work the 18- 20 horse twins all day long. So as you say and i know it to be true, gearing is also a factor. The puzzle is has dirt gotten softer or have loads gotten lighter. The weaker cheaper unit built today with the horse power rating up around automotive powerplants indicated for the engine tells people nothing about what the wheels are going to be capeable of. So the rateing methodologys is/are misleading, as it may have been for years. So Tom, In order to extrapolate the name plate into real usable info Do you have a formula we could tattoo on the hood of our beloved tractors so they make sense? Just yesterday on a 180 mile round trip I was able to put hands on a Legacy XL My local dealer won't carry one. I believe that the Simplicty 9020 or the 4041 would be able to hitch up and move my boat and mow the grass. I also sincerly believe that one horse could also do the task if properly hitched. I'm not so sure that the Legacy XL would be able to do so without overloading an aluminum gearbox or something. The dealer told me the 2w drive model that the Legacy replaced had a two speed rear end and was able to deliver more torque. He said he thought that one may have been able to safely tow the boat but he didn't think the Legacy Xl would do it or he didn't think it would be a good idea. There is a Stiener out there i'm investigating. The 520 model has the same engine manufacture as the Legacy XL But The Diahatsu DM 950DT is in it. That is the turboed brother of the engine in the Legacy XL. My guess is that the components may not have been able to take the extra torque on the Legacy so they opted for the skim milk version. In any event it is a rope walk. Im hopeing to get the formulas understood so i can make a resonable choice that will enable me to only need one tractor for the rest of my days.

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BLT
Webster has three defintions of horsepower. This is the one th pertains to this thread: "a unit of power equal in the U.S. to 746 watts and nearly equivalent to the English gravitational unit of the same name that equals 550 foot-pounds of work per second."

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Leroy
That means my toaster is a 1 1/2 horse @ 1100 watts. Add the spring tension of the toast ejection system and we are possibly bordering on a 2 horsepower unit. Now 550 footpounds would require a lever arm to produce even if we are talking about a 1/4 inch drive, oops, we maybe into sheer at that rate. HELP! One horse would be able to easyily lift 550 lbs. an inch per second. A foot per second i dunno.

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WiscTom
quote:
Originally posted by Leroy
quote:
Originally posted by WiscTom
Hitchin up a team of horses is not going to get you there.
WiscTom I had to gasp several times. The statement that one horse does not a horsepower make. <<<< Catching my breath>>>>. Then the one that followed, he did not define the term to match what a real horse could actually do.<<<<Catching my breath again>>>>. I'm learning all the time and im not armed well enough to argue the points. If the tax man hears that One actual Horse is capeable of three horses. Those who raise horses will go broke. Well maybe not. But could you expand on the explaining, of those two comments.

Well sure. The answer to your first begs the question. Which horse? The thoroughbred at the Derby, the old nag in the back forty, a powerful well trained draft horse in its prime? Clearly the three of them will not put out the same work when hitched up to the wagon. So just on the face of it indicates that one horse does not one horsepower make. However there is more to the story that complicates it some. According to one folktale of how James Watt came to define the term "Horsepower" he did the following. The story goes that Mr. Watt was working on the sales and marketing for his new steam engines. He was trying to sell them to the coal mining industry. Thus he needed a sales pitch to the mine owners with their horses lifting coal up a shaft at a coal mine. He wanted a way to compare the power available from one of his engines to these animals. He experimented some and found that, on average, a mine horse could do 22,000 foot-pounds of work in a minute. (Now this does not mean that he had a 22,000 lb basket of coal that just one mine horse could actually lift a foot, in a minute.) Rather, it was something like a 220 lb basket which was lifted 100ft by one horse in a minute. (In that regard its just math.) He then increased that number by 50 percent and pegged the measurement of horsepower at 33,000 foot-pounds of work in one minute. His motive for derating the available horsepower of a horse? One can only speculate. But, since he was in the business of selling his new steam engines to those horse run mines, it would seem reasonable for him to claim the competitive advantage of being able to state that his 1HP engine will out work any horse in the barn. Another version of the story states that he was experimenting with ponies and somewhat arbitrarily assumed that a horse could do 50 percent more work than his pony. It works out to the same thing. Call it marketing if you will. Regardless, one Horsepower is now 33,000 foot pounds of work per minute.

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WiscTom
quote:
Originally posted by Leroy
That means my toaster is a 1 1/2 horse @ 1100 watts. Add the spring tension of the toast ejection system and we are possibly bordering on a 2 horsepower unit.

Nope. You are heading up the wrong path here. The toaster is not doing any work. Its just heating up bread. No horses involved. However, it will be consuming roughly the same amount of electricity as an 1100 Watt drill press augering wood for the same amount of time. The drill press is appyling a motive force over a distance in a certain time. (It is spinning the drill bit into the wood.) And thus it is doing work.

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WiscTom
Third try. This could go on for weeks. We will be beating a dead horse long before that it seems.
Many have said that the Engines built today do not accurately desribe the horse power because their old 16 horse can out work the 18- 20 horse twins all day long. So as you say and i know it to be true, gearing is also a factor. The puzzle is has dirt gotten softer or have loads gotten lighter. The weaker cheaper unit built today with the horse power rating up around automotive powerplants indicated for the engine tells people nothing about what the wheels are going to be capeable of. So the rateing methodologys is/are misleading, as it may have been for years. So Tom, In order to extrapolate the name plate into real usable info Do you have a formula we could tattoo on the hood of our beloved tractors so they make sense?
You are absolutely right of course. And no, the dirt has not gotten lighter or softer. What has changed is the test conditions under which the engine recieves its nameplate rating. Recall if you will the automotive horsepower wars of the late sixties. Clever, and most disengenous, car makers found the way to trick up thier engines to push the dynomometer harder. They would remove things like water pumps and oil pumps to get that coveted top Hp rating. But for the nameplate, the actual engine sold to the consumer did not change. This backfired on them, but it illustrates the point. The deal you are seeing is that an old iron 16 horse can indeed out perform a modern 18 hp twin any day of the year. They (SAE) simply changed the test conditions leading to nameplate Hp. Not that I know how the old 16 came to be rated, nor the modern twins. But you can assume that something occured which enabled the newer lighter twins to run harder for the dyno. Maybe they pushed up the RPMs on the modern engine for the test. Maybe they ran it in a much colder room. They could have used the better modern lubricants. Better fuels, better bearings, better steel. The list is all but endless. This is not to say that SAE is lying in establishing nameplate ratings. It is only a recognition of the fact that changing consumer demand leads to improvements. But, if at the time your old engine was made the manufacturers, were more concerned with plain old durablility and now they are seeking ever higher Hp ratings you can easily envision the result. That said, some of those changes, like better lubricants, allow your old iron to run stronger than what is stated on the nameplate. Yet, since the old engines are not retested when something better comes along, the 30 yr old nameplate rating is not directly compareable to today's. Yes indeed the methodology is misleading. There will be no simple formula to tattoo anywhere. The only test which seems to be reliable through the decades is that conducted by the Univ of Nebr. They merely hook up a retail version of a farm tractor to thier test sled. And, with the assistance of a big old spring scale, the determine how much it can pull. No tricks, no ploys. Just horsepower.

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Leroy
Thanks Tom, No dead horse beating, intended. The tricks are played on the dealer, the dealer is more or less obligated to play the dumb guy, because infact he will not know more about the hp rating, anymore than, we here do, now. We end up holding a bag of deflated goods and if we believe in our hearts that a 30 HP unit is a 30 hp unit and give it 29 hp job something may give, or it may just sit and spin, making you wish you had gone to the more beef side, of the tractor isle.

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Tom Deutsch
One word missing in all of this horsehockey -- torque! I know there are a bunch of engineers out there who could explain over-square and under-square (talkin bout bore versus stroke measurements) and flywheel weight. Who said "give me a big enough lever..."? I'm an amateur mechanic, but I'd bet torque is most of the reason the old 10 and 16 hp lumps seem to out-perform twins with higher numbers. Also, as a marketing/advertising person, I can tell you for sure it might also seem stronger because you LIKE the the older stuff better (hey, no offense, so do I).8D

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WiscTom
quote:
Originally posted by Tom Deutsch
One word missing in all of this horsehockey -- torque! I know there are a bunch of engineers out there who could explain over-square and under-square (talkin bout bore versus stroke measurements) and flywheel weight. Who said "give me a big enough lever..."? I'm an amateur mechanic, but I'd bet torque is most of the reason the old 10 and 16 hp lumps seem to out-perform twins with higher numbers. Also, as a marketing/advertising person, I can tell you for sure it might also seem stronger because you LIKE the the older stuff better (hey, no offense, so do I).8D
Darn tootin hey. It isn't the whole story, but for what we do with these little brutes it makes up for most of it. Ain't nothin better than reliable low rev torque. Archimedes is the guy with that phrase.

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WITom
I also believe that torque is the key here. The old 1 banger 16 hp will have more torgue than the new twins. A good example is the old John Deere 2 cylinder tractors. If any of you have ever watched one in a tractor pull, you'll know what I mean. Those old buggers will pull right down to where you think they are about to die and end up spinning the tires. You'd swear they are only running at 10 rpm's, but they have so much torque from those big jugs that they just won't die. The old 16 hp one cylinder is producing more torque from that big jug than the smaller jugs on the twins.

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