# Does one horsepower really = the power of one horse? **URL:** \ **Category:** Factual Questions\ **Created:** [September 29, 2004, 3:14pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673 "2004-09-29T15:14:44Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\ **Post date:** [September 29, 2004, 3:14pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/1 "2004-09-29T15:14:44Z")
I was watching the Travel channel yesterday and they had a program about people that build monster trucks for tractor pull competitions. He boasted that he had four engines in his rig that generate 14,000 HP and can drag 60,000 pounds against the ground. That was pretty impressive but I was thinking that if you really had 14,000 live, medium sized horses hooked up together somehow, you could do much, much better than that. Likewise, I don’t _think_ a one horsepower motor would do very well powering a carriage with several people in it or plowing an uneven, rocky field. Horses have, and continue to do all of that. I know the [definition of a horsepower unit of measure.](http://www.google.com/search?hl=en&lr=&ie=UTF-8&oi=defmore&q=define:HORSEPOWER). What I want to know is how that compares to the work that an actual horse can do and why they choose the standard that they did? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [September 29, 2004, 3:26pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/2 "2004-09-29T15:26:27Z")
> [@Shagnasty](#): > > IWhat I want to know is how that compares to the work that an actual horse can do and why they choose the standard that they did? They (they being one James Watt) chose the unit based on actual experimental results with real horses: > [@](#): > > One horsepower was originally defined as the amount of power required to lift a mass of 33 000 pounds through a vertical distance of 1 foot in 1 minute. This is also stated as 550 foot pounds per second (fps). James Watt worked out this figure for the horsepower when he did some experiments on horses hauling coal. He found that horses could haul coal at the average rate of 22 000 foot-pounds per minute. He then applied a correction factor which gave the current value of 33 000 or 550 fps. So, I’d say that, yes, one horse can output about one horsepower, on average. ---
**Author:** ![alterego](https://avatars.discourse-cdn.com/v4/letter/a/6bbea6/32.png) [@alterego](https://boards.straightdope.com/u/alterego)\ **Post date:** [September 29, 2004, 3:52pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/3 "2004-09-29T15:52:43Z")
It would be a great car commercial to strap (or just realistically animate) 300 horses to a chariot and race whatever SUV they are advertising 🙂 Maybe they’ve done it. I haven’t seen it. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [September 29, 2004, 4:09pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/4 "2004-09-29T16:09:50Z")
> [@Shagnasty](#): > > That was pretty impressive but I was thinking that if you really had 14,000 live, medium sized horses hooked up together somehow, you could do much, much better than that. Likewise, I don’t _think_ a one horsepower motor would do very well powering a carriage with several people in it or plowing an uneven, rocky field. Horses have, and continue to do all of that. I think 14,000 horses would have better traction than one monster truck so yeah…I’d expect they’d do better too. That does not mean however that 14,000 horses have more energy output…just better able to focus that output to a given task (assuming of course you could actually get 14,000 horses to pull in unison). ---
**Author:** ![Neurotik](https://avatars.discourse-cdn.com/v4/letter/n/91b2a8/32.png) [@Neurotik](https://boards.straightdope.com/u/Neurotik)\ **Post date:** [September 29, 2004, 4:17pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/5 "2004-09-29T16:17:00Z")
> [@alterego](#): > > It would be a great car commercial to strap (or just realistically animate) 300 horses to a chariot and race whatever SUV they are advertising 🙂 > > Maybe they’ve done it. I haven’t seen it. Well, it would be great advertising since the 300 horses still wouldn’t have a top speed much over 40 mph. ---
**Author:** ![Gunslinger](https://avatars.discourse-cdn.com/v4/letter/g/4491bb/32.png) [@Gunslinger](https://boards.straightdope.com/u/Gunslinger)\ **Post date:** [September 29, 2004, 4:59pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/6 "2004-09-29T16:59:52Z")
> [@Q.E.D.](#): > > They (they being one James Watt) chose the unit based on actual experimental results with real horses: > So, I’d say that, yes, one horse can output about one horsepower, on average. _Why_ did he apply the half-a-horse correction factor? I’ve wondered that ever since I was little and read a trivia bit to the effect that one horsepower is actually 1.5 horses’ worth. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [September 29, 2004, 5:06pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/7 "2004-09-29T17:06:05Z")
> [@Gunslinger](#): > > _Why_ did he apply the half-a-horse correction factor? I’ve wondered that ever since I was little and read a trivia bit to the effect that one horsepower is actually 1.5 horses’ worth. I believe it was to allow for frictional losses. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [September 29, 2004, 5:14pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/8 "2004-09-29T17:14:50Z")
> [@Whack-a-Mole](#): > > I think 14,000 horses would have better traction than one monster truck… Agreed. In the OP, the (claimed) 14,000 hp is said to be capable of dragging 60,000 lbs - just over 4 lb/hp. I think a horse could do a bit better than that. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [September 29, 2004, 5:26pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/9 "2004-09-29T17:26:47Z")
Another way to look at this is by means of the equation: power = force \* speed Using this and assuming a coefficient of friction of 1.0 (that is, it takes one pound of force to drag one pound of weight), we can calculate that a 14,000 hp truck should be capable of dragging 60,000 lbs at a speed of 87 mph - obviously absurd. I think we can conclude that the extreme power is needed to start the weight moving, and that traction is a significant issue. ---
**Author:** ![Omphaloskeptic](https://avatars.discourse-cdn.com/v4/letter/o/bcef8e/32.png) [@Omphaloskeptic](https://boards.straightdope.com/u/Omphaloskeptic)\ **Post date:** [September 29, 2004, 7:00pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/10 "2004-09-29T19:00:05Z")
Was this really a 14,000 horsepower engine? I don’t know much about truck engines but this seems an order of magnitude too big to me. Googling for semi tractors I can find a lot in the 300-500 horsepower range; four of these might make 1400 horsepower, but 14000 seems dubious. ---
**Author:** ![Dag\_Otto](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@Dag\_Otto](https://boards.straightdope.com/u/Dag_Otto)\ **Post date:** [September 29, 2004, 7:59pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/11 "2004-09-29T19:59:22Z")
> [@Omphaloskeptic](#): > > Was this really a 14,000 horsepower engine? I don’t know much about truck engines but this seems an order of magnitude too big to me. Googling for semi tractors I can find a lot in the 300-500 horsepower range; four of these might make 1400 horsepower, but 14000 seems dubious. Well, you need to remember that these are not your run of the mill truck engines. I can’t find any truck specific links right away, but here are[some tidbits from the NHRA](http://www.nhra.com/streetlegal/funfacts.html). With 4 engines, each is putting out 3,500 hp. Doesn’t seem unreasonable. ---
**Author:** ![danceswithcats](https://avatars.discourse-cdn.com/v4/letter/d/9e8a1a/32.png) [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)\ **Post date:** [September 29, 2004, 8:10pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/12 "2004-09-29T20:10:49Z")
Remember that in addition to moving the attached load, the horse has to move the horse, of course. 😉 ---
**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\ **Post date:** [September 29, 2004, 8:36pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/13 "2004-09-29T20:36:41Z")
> [@Omphaloskeptic](#): > > Was this really a 14,000 horsepower engine? I don’t know much about truck engines but this seems an order of magnitude too big to me. Googling for semi tractors I can find a lot in the 300-500 horsepower range; four of these might make 1400 horsepower, but 14000 seems dubious. They were actually modified jet engines from a military helicopter. There were four of them on one rig. That was for the “unlimited” category. In lower classes, some people also used old souped up aircraft engines for less multi-thousand horsepower performance. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [September 29, 2004, 9:09pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/14 "2004-09-29T21:09:10Z")
I seem to remember being taught that the measure of how much a horse could pull was for a particular horse in England. Wasn’t it something like the strongest horse then known? ---
**Author:** ![Omphaloskeptic](https://avatars.discourse-cdn.com/v4/letter/o/bcef8e/32.png) [@Omphaloskeptic](https://boards.straightdope.com/u/Omphaloskeptic)\ **Post date:** [September 29, 2004, 10:09pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/15 "2004-09-29T22:09:05Z")
> [@Shagnasty](#): > > They were actually modified jet engines from a military helicopter. There were four of them on one rig. That was for the “unlimited” category. In lower classes, some people also used old souped up aircraft engines for less multi-thousand horsepower performance. OK. Guess I should have taken the description “monster” at face value… ---
**Author:** ![Gorsnak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gorsnak/32/7587_2.png) [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)\ **Post date:** [September 29, 2004, 11:57pm UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/16 "2004-09-29T23:57:20Z")
At horse pulls the draft horses will pull two to three times their own weight (10000-12000lbs with two horses). The full pull is 14’, and the weight is on a flat-bottomed sledge pulled over sand. I don’t know what that works out to, but I’m pretty sure that’s more than 2hp those guys are putting out. Of course, they certainly couldn’t maintain that effort for any appreciable length of time. ---
**Author:** ![saluki\_fan](https://avatars.discourse-cdn.com/v4/letter/s/b2d939/32.png) [@saluki\_fan](https://boards.straightdope.com/u/saluki_fan)\ **Post date:** [September 30, 2004, 12:07am UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/17 "2004-09-30T00:07:34Z")
doesn’t so many volts or ohms equal one hp? I remember hearing something about it in an intro to electrical circuits class once. ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [September 30, 2004, 12:20am UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/18 "2004-09-30T00:20:27Z")
> [@saluki\_fan](#): > > doesn’t so many volts or ohms equal one hp? I remember hearing something about it in an intro to electrical circuits class once. Watts are a power unit. 1 hp = about 750 watts. I’m too lazy to look up the exact conversion at the moment. Volts measure potential, ohms resistance. A watt is one ampere of current flowing across 1 volt of potential. ---
**Author:** ![RandomLetters](https://avatars.discourse-cdn.com/v4/letter/r/8edcca/32.png) [@RandomLetters](https://boards.straightdope.com/u/RandomLetters)\ **Post date:** [September 30, 2004, 1:59am UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/19 "2004-09-30T01:59:54Z")
1 horsepower = 745.699872 Watts - I love google. ---
**Author:** ![GusNSpot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gusnspot/32/436_2.png) [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)\ **Post date:** [October 1, 2004, 6:27am UTC](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673/20 "2004-10-01T06:27:09Z")
Back in the 1800’s when the old steam tractors were making their appearence, they were rated in _drawbar_ HP. It is figured different today but as I heard it from old timers, they just kept hooking horses to the tractor and when the horses won the pull, they just subtracted one horse and you then had a tractor with 98 drawbar HP. YMMV [Next page](https://boards.straightdope.com/t/does-one-horsepower-really-the-power-of-one-horse/266673.md?page=2)