Jerry Christiansen
12-27-2009, 07:10 PM
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.
http://i170.photobucket.com/albums/u249/jtchrist/Prony%20Brake/measuringhorses002.jpg
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!
http://i170.photobucket.com/albums/u249/jtchrist/Prony%20Brake/measuringhorses003.jpg
And another team on the way.
http://i170.photobucket.com/albums/u249/jtchrist/Prony%20Brake/measuringhorses004.jpg
The horses are all hooked up and ready to go.
http://i170.photobucket.com/albums/u249/jtchrist/Prony%20Brake/measuringhorses001.jpg
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.
Later,
Jerry Christiansen
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.
http://i170.photobucket.com/albums/u249/jtchrist/Prony%20Brake/measuringhorses002.jpg
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!
http://i170.photobucket.com/albums/u249/jtchrist/Prony%20Brake/measuringhorses003.jpg
And another team on the way.
http://i170.photobucket.com/albums/u249/jtchrist/Prony%20Brake/measuringhorses004.jpg
The horses are all hooked up and ready to go.
http://i170.photobucket.com/albums/u249/jtchrist/Prony%20Brake/measuringhorses001.jpg
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.
Later,
Jerry Christiansen