Measuring Horsepower of Horses

Discussion in 'Prony Brake' started by Jerry Christiansen, Dec 27, 2009.

  1. Jerry Christiansen

    Jerry Christiansen Mega Poster WMSTR Lifetime Member

    During the 2009 WMSTR show we decided we should measure the horsepower of horses. Knowing that the question, “How much horsepower can a horse do?” would be asked; a bit of research was done.
    In the mid 1700’s James Watt improved steam engine technology so that they were economically feasible to operate. To describe what a steam engine could do for a mine owner or a factory owner, he compared the amount of power his engine could do to what a horse could do. A horsepower is defined as 33,000ft-lb of work per minute, which is the same at 550ft-lb/s.
    Two different stories are commonly found that describe how Watt decided to use 550ft-lb/s. One story describes how he studied horses turning a mill wheel and determined that a horse could do 32,572ft-lb/min which he rounded to 33,000ft-lb/min. The other story is that Watt determined that a horse could do 22,000ft-lb/min. He then increased that value by 50% when rating his engine to 33,000ft-lb/min.
    If the second story is correct, a flesh and blood horse should be able to do 2/3 of a James Watt horsepower. Those people that recount the first story usually point out that a living horse can do about 0.6 of a horsepower over a period of time, with higher values for a short burst. Which ever story you chose to believe, we should expect a horse to be able to put out about 2/3 of a horsepower over a period of time.

    Enough of the history lesson, lets hook up some horses!

    We got a shorter belt and put the Blue Brake between the threshing machine in the horse area and the horsepower (this time 'horsepower' means the machine the horses walk around to create rotary motion). The threshing machine can be seen behind the bundle wagon. The horsepower is behind the camera.


    Watching the horses get hooked up was a good show all by itself. Don’t ask me to name all the people. Please don’t ask me to name the horses!


    And another team on the way.


    The horses are all hooked up and ready to go.


    The machine the horses go around (or as Jim and I called it - the roundy-roundy) is the horsepower. A rotating shaft that the horses have to step over lies on the ground and comes to the red, two wheel device on the left. The red device uses a bevel gear set to spin the pulley that powers the flat belt.

    More pictures, maybe a video and data to follow.

    Jerry Christiansen
  2. Jerry Christiansen

    Jerry Christiansen Mega Poster WMSTR Lifetime Member

    Here is a view from the road on the west side of the Horse Area. In this picture the Brake is hooked up, the first team of horses is getting in to position and the others are on the way.


    More horses on the way.

    Video here

    Hooking up horses.

    Jim is doing some narration in the next video. Mark Carr is running the Brake and putting load on the horses. Jim and I have no idea how hard horses can be pulled, so we needed someone that knew horses to run the Brake. Some of the other horse people ‘volunteered' Mark for the job. Mark ran the Brake and watched the horses. Jim and I recorded numbers. Here Mark adjusted the Brake to what “they like to pull”.

    Video here

    Adjusting load.

    About the time Jim read the rpm, Mark changed the load. We didn’t get a pair of numbers recorded for the speed Jim read.

    The next video is from the south side of the horsepower. This really shows how quiet the horses work. Even from this distance Jim’s narration can be heard.

    Video here

    Quiet workers

    More in a bit,

    Jerry Christiansen
    Last edited by a moderator: Mar 23, 2015
  3. Jerry Christiansen

    Jerry Christiansen Mega Poster WMSTR Lifetime Member

    Hi all,

    I realized when I looked at this thread again that I did not report results of how much horsepower the horses produced. Please be kind in any messages about forgetfulness in old age!

    Mark adjusted the load up and down several times and we recorded the following values

    Pounds . . .RPM. . . Horsepower
    13 . . . . . . .381 . . . . . 4.9
    17 . . . . . . .366 . . . . . 6.2
    16 . . . . . . .406 . . . . . 6.5

    19 . . . . . . 387 . . . . . 7.4
    20 . . . . . . 376 . . . . . 7.5
    31 . . . . . . 391 . . . . . 8.2

    18 . . . . . . 418 . . . . . 7.5

    11 . . . . . . 347 . . . . . 3.8
    12 . . . . . . 362 . . . . . 4.3
    17 . . . . . . 355 . . . . . 6.0
    20 . . . . . . 311 . . . . . 6.2
    22 . . . . . . 327 . . . . . 7.2

    Measuring horses is very different from measuring gasoline, diesel or steam engines. When measuring engines the rpm will drop a bit before the governor starts opening up as load is increased. Then as more load is applied the governor opens, the engine gets louder and the rpm will hold fairly steady for several readings. Finally, governor is holding the throttle wide open, the engine is roaring and as more load is applied the rpm drop off. If the operator wants, the load can be adjusted to a previous value and the same, or very similar, rpm will be read giving nearly the same horsepower.

    Horses are different. Horses just keep on pulling. Adding load does not cause them to make more noise. A particular set of numbers is difficult to duplicate because at the same load they may pull faster or slower giving a different power value.

    The folks in the horse area thought the horses could produce more power than what we measured. One of the reasons we didn’t try for higher values is that a couple of the wooden poles the horses were hooked up to are cracked. The cracked poles were bending quite a bit and we didn’t want to break them. Plans are in the works to replace the cracked poles for next year.

    Plan on coming to the horse area Sunday morning when we try this again.

    Jerry Christiansen
  4. Jerry Christiansen

    Jerry Christiansen Mega Poster WMSTR Lifetime Member

  5. vnanosky

    vnanosky Mega Poster Administrator WMSTR Lifetime Member

    I have updated your links on the older posts so they work
    mrnewway likes this.
  6. Jerry Christiansen

    Jerry Christiansen Mega Poster WMSTR Lifetime Member

    Hi Vern,

    Thanks for updating Post #3. Post #3 contained 3 videos, in post #4 there are 5 videos.

    The second video in #4 (last characters in the URL are 19.mp4) and the third video ( 17.mp4) are 'new'. I am not sure why I didn't include them the first time around.

    We haven't measrued horsepower of horses for a couple years. Maybe we need to do this agian this year.

    Jerry Christiansen

  7. Ned

    Ned Mega Poster WMSTR Lifetime Member

    NCM_0100.JPG I've had this picture in my collection for awhile. I've been meaning to ask you Jerry how many oxen does it take to make one horse power?
    A little background on this photo it was taken by Stillwater MN I don't know when but there are 12 oxen hooked to the "roundy round"

    Hopefully the picture works :praying:
  8. Jerry Christiansen

    Jerry Christiansen Mega Poster WMSTR Lifetime Member


    I have no idea what the ox to horse ratio is. We will have to talk to Mark C, Roger E and the rest of the horse people about bringing enough oxen to the show to run the test.

    Jerry Christiansen
  9. Ned

    Ned Mega Poster WMSTR Lifetime Member

    I'm not going to lie I'm a little disappointed I figured you would have come up with take the spots on the right hand side of the ox times that by the number of spots on the lefts side divided by the number of horns add the barometric pressure taking into account the soil the ox are going roundy round in, but all I get is an I don't know.

    Just so very disappointed :sad:
  10. cjmlarson

    cjmlarson Mega Poster WMSTR Lifetime Member

    I am with you on this Ned! :Shrugs: So So So disappointed. That is pretty much a cop-out especially from a teacher:confused:....
  11. M Kerkvliet

    M Kerkvliet WMSTR Past President Administrator WMSTR Lifetime Member

    Back off guys... I am sure the lines (or cellular airwaves) are burning from Casselton to Fertile right now as Jerry and Jim come up with some sort of answer to this query... Just wait! Spring meeting perhaps... :Shrugs:
  12. Ned

    Ned Mega Poster WMSTR Lifetime Member

    I was just trying to help with lack of steam at the MSEA steam up I figure those two wouldn't have much to talk about
  13. Jerry Christiansen

    Jerry Christiansen Mega Poster WMSTR Lifetime Member

    A bit of searching on someone’s part found information that Clayton and Ned should find interesting. The entire article can be seen at:

    Here is a small part of the article.

    Animal Power

    Copyright Tim Lovett Mar 2004, June 2007

    The working speed for most draught animals is about 1 metre/second (3.6 km/h, 2 mph). A Brahman bull consumes about 3.3 Joules for each Joule of work. There are limitations on the performance of animals, such as sensitivity to food supply, getting sick or just having a bad day.

    Screen shot 2015-04-07 at 7.23.45 PM.png

    Note: For animals of different weight the power output and energy output per day may be adjusted proportionately. Source: Tools for Agriculture, 1992

    Screen shot 2015-04-07 at 7.23.57 PM.png

    For a hard day's work the horse reigns supreme, delivering 500W for 10 hours. The ox is known for its compliance and is less fussy about food - a good choice for the less demanding applications. The camel has the highest power output. Forget the donkey

    A couple columns to note in the first table are the pull weight ratio and working hours per day. The pull weight ratios of the horse and ox are close (0.13 and 0.11), but if you do a bit of math the ox’s pull weight ratio is about 15% less than the horse’s ratio. The working hours per day make the ox look like a real slacker.

    For most of us, it is all about POWER. The second table shows the horse producing 0.864hp with the ox producing 0.576hp. The ox’s power is about 33% less than the horse’s power. Another way to say that is: The horse produces 150% as much power as the ox.

    Now that this information has been revealed, Ned and Clayton will not toss and turn all night worrying and wondering. The will be able to get a full night’s sleep.

    I am not certain if the last statement in the article has any political references or not.


    Jerry Christiansen
    M Kerkvliet and s.d. jon like this.
  14. cjmlarson

    cjmlarson Mega Poster WMSTR Lifetime Member

    With you taking a while to respond, I figured you were being the teacher that you are;)....Hope every one knows that these post have been all in fun :p.
    While reading this the OX kinda reminds me of Ned:hide:
    For my sake Jerry, at least you said forget the Donkey:not_worthy:
    s.d. jon likes this.
  15. Ned

    Ned Mega Poster WMSTR Lifetime Member

    Ouch!!! Clayton kinda a low blow
    s.d. jon likes this.
  16. cjmlarson

    cjmlarson Mega Poster WMSTR Lifetime Member

    Hey Ned, Danger boy gave me the idea to use you for that one.:help2:
    s.d. jon likes this.
  17. Jerry Christiansen

    Jerry Christiansen Mega Poster WMSTR Lifetime Member

    Hi Clayton,

    You bet these posts are in fun and are fun. The "Foget the Donkey" isn't my line, that came from the article. A certain fellow from Fertile and I will have to study this information and expound on it.

    Jerry Christiansen
  18. s.d. jon

    s.d. jon Mega Poster WMSTR Lifetime Member

    This is all very interesting. Didn't Festus usually ride a donkey??? :gathering:
  19. Ned

    Ned Mega Poster WMSTR Lifetime Member

    Sure blame poor innocent Danger Boy :eek:...
  20. M Kerkvliet

    M Kerkvliet WMSTR Past President Administrator WMSTR Lifetime Member

    I had to go back and read that sentence twice! For some reason I kept seeing "...forget the Doxey" :Shrugs:

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