Thread Tools Display Modes
Old 01-01-2010, 06:54 PM
Join Date: Dec 2006
Location: Puerto Rico
Posts: 6,786
How many horses in a horse? (HP in a mammal)

If I wanted to picture a horse capable of delivering one HP over a work day, what kind of horse am I looking at? A thoroughbred, a draft horse, a glue factory reject, a non-existent superhorse?

The wiki entry states that the current measure might be more than an actual horse can deliver for any useful length of time.

What would be the actual power rating of the common types of modern horses? Wiki also mentions a peak performance of almost 15 HP from a horse but doesn't go into much detail as to what kind of horse, doing what and for how long?

What's the power output of a racing horse during a race distance (which varies, I know)?

In short, tie the mechanical unit to actual animal performance in any way you can.
Old 01-01-2010, 07:12 PM
Join Date: Jul 2001
Location: Arizona
Posts: 27,611
Not sure about the power comparison of the horse types, but here is information mentioning the type of horse used to figure out the original HP, the Draft Horse:
James Watt set to work devising a way of measuring the amount of Work that his engines could do. The obvious benchmark was the horse, or more specifically the Draft Horse that was the ‘industry standard’ of the time.

Using a hoist, he conducted experiments to determine how quickly a Draft Horse could raise a heavy load. He observed that a load of 550 Pounds (nearly ¼ of a ton) could be raised at a rate of 1 foot per second. That’s 550 foot-pounds per second of work done. Multiply by 60 and that is 33,000 foot-pounds per minute of work or 1 Horsepower (1 HP).

So - Horsepower is a measure of the engines rate of work i.e. how much work in a given time. The higher the horsepower the more work it can do or the faster it can do it.
Simple really.
Old 01-01-2010, 07:19 PM
Join Date: Apr 2009
Posts: 4,566
Continued Reading: A few previous threads on horsepower.
Old 01-03-2010, 12:51 PM
Join Date: Dec 2006
Location: Puerto Rico
Posts: 6,786
There you go. I knew this had to be covered ground. Will read and come back with further questions if.

Old 01-03-2010, 01:33 PM
Straight Dope Science Advisory Board
Join Date: Mar 2000
Location: With Candy Darling
Posts: 15,989
Nobody ever remembers...
How did we end up with the “horse” in horsepower? The term was coined by James Watt (1736-1819), the British inventor best known for his improved steam engines, who used the term to relate steam engine performance to that of horses. At the time horses were the primary energy source for applications ranging from pumping water from mines and turning grinding mill wheels to pulling carts and loads. Although sources differ on exactly how Watt arrived at the number, it’s generally thought that in 1782, he noted how quickly a brewery horse could turn a mill wheel of a certain radius, estimated the amount of force the horse needed to exert to turn the wheel, did the math, and came up with a value of 32,400 ft-lbf/min, later rounded to 33,000 ft-lbf/min. Comparing the power output of a steam engine to an equivalent number of horses was an easy way for prospective engine purchasers to compare power ratings, so the term stuck.

What type of horse was a brewery horse? In England at the time a work horse most likely would have been one of the three British "heavy breeds" – the Suffolk punch, the shire horse, and the Clydesdale. The Clydesdale is said to have originated in the latter 1700s, perhaps too late to be a common work horse at the time Watt was doing his horsepower calculations. So it seems likely the horse in question was either a Suffolk punch or a shire horse.

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump

All times are GMT -5. The time now is 07:33 AM.

Send questions for Cecil Adams to: [email protected]

Send comments about this website to:

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Copyright © 2018 STM Reader, LLC.

Copyright © 2017
Best Topics: everclear taste nigger bomb browse hulu dog's anus swollen white grapefruit groundhog killer height advantage hard bruise annapolis pronunciation booger glue dots realistic spaceship german word for glue time between star wars episode 3 and 4 best buy remote start installation double chin exercises do they work jimmy johns vs subway pecked to death by ducks is a phd in philosophy worth it average time to grow a beard dbz abridged drinking game how many feet before turn signal where can you purchase boric acid bowling alley installation cost toast english muffins in the oven we're so sorry uncle albert