doesn’t it have something to do with the breeding of the horses, the way it is measured, and the comparative strength of horses today vs. when they made the measurement?
So that’s an interesting thought and I think we could say that could factor in to a lager discussion of horsepower comparisons- but it’s actually subtler.
Horse power exists because steam engines exist and at a time where horses were dominant used yo move loads or power machines like mine lifts or flywheels- it became necessary to describe to potential customers how many horses a machine replaced. TOTAL.
Confused? Ok. Let’s say you run an old timey mine and you have a shaft with a belt to bring up material from your miners. Let’s say it is powered by a single horse turning a wheel and you have miners working around the clock, four shifts of 6 hours. Well- you can’t work a single horse 24 hours and having a horse do heavy work like that for 6 hours straight no breaks etc. is cruel but also your horse probably won’t last long. So you might have 10+ horses you need to keep and feed so you can work them in shifts.
So if we replaced your horses with a steam powered generator that could run 24/7, we just took over the work of 10 horses! So this is sort of how things started out. Then a bunch of people sort of estimated what they thought the actually capacity of a horse to do labor was, and then a guy actually got a horse and tried it out. So it isn’t like he tested 1,000 horses in super strict settings or anything- he got A horse and did A test and went with it. He made a formula and that sort of became the standard because why not? And anyone that wanted to argue would have to go measure horses and then fight inertia over the whole deal and the calculation didn’t come off as insane to anyone and more or less worked. Of course over time more standards would come out and the horsepower would essentially end up being completely divorced from horses more or less- but there’s more!
So a horse is capable of about 15hp. This was calculated more than half a century after the horsepower was established. Why so much variance…? Actually… it isn’t! Think about it. Most humans can produce around 1.5hp. But for most humans this is your PEAK under ideal circumstances. So imagine the fastest you can run a mile. Now keep that pace for 2 miles. Now 5. Could you? Probably not. The average horsepower you produce is much lower.
Horses are the same. A horse may be able to generate 15ho for brief periods occasionally- but when we talk about using horses for work or transportation we are generally interested in their steady ability to do a job or travel a distance, not a few seconds or minutes of peak output.
And it turns out that when you calculate backwards from that 15 horse power- and you apply the limits of what were the established guidelines for how hard or long or intensely and frequently you could work a horse- when we are talking about a steady and sustainable output- horses end up by those standards producing about 1hp!
So a 1hp plow can’t theoretically compete with a horse that is pushing its limits or even going a bit hard, but it should theoretically be about equal to the work a reasonably cared for horse working on a sustainable pace would do.
Horse power exists because steam engines exist and at a time where horses were dominant used yo move loads or power machines like mine lifts or flywheels- it became necessary to describe to potential customers how many horses a machine replaced. TOTAL.
Confused? Ok. Let’s say you run an old timey mine and you have a shaft with a belt to bring up material from your miners. Let’s say it is powered by a single horse turning a wheel and you have miners working around the clock, four shifts of 6 hours. Well- you can’t work a single horse 24 hours and having a horse do heavy work like that for 6 hours straight no breaks etc. is cruel but also your horse probably won’t last long. So you might have 10+ horses you need to keep and feed so you can work them in shifts.
Horses are the same. A horse may be able to generate 15ho for brief periods occasionally- but when we talk about using horses for work or transportation we are generally interested in their steady ability to do a job or travel a distance, not a few seconds or minutes of peak output.
So a 1hp plow can’t theoretically compete with a horse that is pushing its limits or even going a bit hard, but it should theoretically be about equal to the work a reasonably cared for horse working on a sustainable pace would do.