What Is Horsepower & Why It's A Dumb Unit - America vs Metric

күнү жарыяланды 2020-ж., 28-окт.
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What is the difference between HP, CV, PS, and kW? Why is horsepower a dumb unit?
Horsepower vs Torque - A Simple Explanation: kglove.info/sun/video/rWWuqpimx5awz4s.html
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Horsepower is a unit of power created by James Watt in the 1700's. Who knew all these years later we'd still be using a unit he developed to compare steam engines to horsepower. We'll go through Watt's back of the napkin math, discuss in simple terms what horsepower means, and look at metric horsepower as well: PS, CV, and the many other abbreviations. Whether metric or imperial, horsepower as a unit makes no sense at all. We'll wrap up the video learning what unit we should actually be using.
Related Links:
Derivation of HP - aapt.scitation.org/doi/10.1119/1.1999088
HP vs PS vs CV - www.autoweek.com/news/technology/a1820831/what-ps-metric-horsepower-autoweek-explains/
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  • Steve Phillips

    Steve Phillips

    2 саат мурун

    This is why large Diesel engines are in kw. As a diesel mechanic, I remember working on 3406b’s that were 425 hp/317 kw.
    Thanks for the video explanation.

  • Stephen Powdexter

    Stephen Powdexter

    2 күн мурун

    Jokes aside, I recall my college physics from long ago and exhilarating it made me feel to understand these things. It’s really crazy when you think about how our American system sticks with a screwy measurement unit.
    I do rem the the SAE system incorporates gravity in its unit, pounds, whereas the metric uses MASS, so you have to factor in gravity to compare them.
    The math, I don’t closely follow but well done.

  • TerminalVelocity

    TerminalVelocity

    5 күн мурун

    preaching to the choir man, i love it, lets make the switch now.

  • Consumer This

    Consumer This

    18 күн мурун

    Says no one lol - I’ll take a 800 hp hellcat over my 400hp Stinger GT!

  • Gustavo Figueiredo

    Gustavo Figueiredo

    22 күн мурун

    So, did he just came up with 180lbf out of nowhere? Is that an average for all horses?

    • GH1618

      GH1618

      20 күн мурун

      It has more to do with the mill than the horse. He probably looked at typical mills designed to be driven by a single horse. They would probably have been similar in design, because experience would have led mill builders to a standard design. He could easily have measured the force required to turn one.

  • Gustavo Figueiredo

    Gustavo Figueiredo

    22 күн мурун

    Wow, and I thought the imperial system was weird...

  • BajaDeezNutz

    BajaDeezNutz

    27 күн мурун

    The US is known for its robust measurement of units that blows the water out... in gallons.

  • Victor Batres

    Victor Batres

    27 күн мурун

    Good explanation however I am still a little confused. I am guessing there are a lot of variables involved in determining horse power . I will review a few times and maybe it will sink in.

    • GH1618

      GH1618

      27 күн мурун

      It is 550 ft-lbs per second. Only three variables. I’m not sure how engineers measure the power curve of an engine, though. There are practical considerations.

  • Jacques Taulard

    Jacques Taulard

    28 күн мурун

    Fantastic explanation!

  • Brian Stanaland

    Brian Stanaland

    Ай мурун

    What's the conversion from US horsepower to WATT?

    • GH1618

      GH1618

      28 күн мурун

      One Hp is 0.746 kW. It’s easy to look such things up.

  • Edward Norton

    Edward Norton

    Ай мурун

    What is the difference between horsepower (hp) and British horsepower (bhp)?

  • Justin Melo

    Justin Melo

    Ай мурун

    you lost me at Horse Power

  • GH1618

    GH1618

    Ай мурун

    It would be interesting to put the unit to a test. Find a horse-driven mill typical of those used in Watt’s time. A one-Hp electric motor should be able to drive the mill at the rate a walking horse would.

  • LXIX Turner

    LXIX Turner

    Ай мурун

    Whatever horse he used doesn't even know he/she is a legend

  • G G nez

    G G nez

    Ай мурун

    It's like American football, only they understand it because in real football they are not good at all!!!

    • GH1618

      GH1618

      Ай мурун

      Tell that to members of the World Champion US women’s soccer team.

  • Andrew Iannello

    Andrew Iannello

    Ай мурун

    Nice history lesson 👍

  • Ian López

    Ian López

    Ай мурун

    Me: sees interesting topic from this guy and opens it
    Him: a whiteboard that looks just like algebra class
    Me: doesn't want to know anymore what horsepower is

    • Ian López

      Ian López

      Ай мурун

      @GH1618 this is the answer i need. Thanks

    • GH1618

      GH1618

      Ай мурун

      Short answer: Power is the rate of doing work. One horsepower is the size of the most powerful in-sink garbage disposals for residential use.

  • flippert0

    flippert0

    Ай мурун

    So, we are honoring James Watt by abandoning and denigrating his original work? As a side-note: what James Watt measured was the average work a horse could carry out during a 8 or 10 hour day. Over a short period of time one horse can have as much as 10 or even 15 hp!

  • Svein Arne Løkken

    Svein Arne Løkken

    Ай мурун

    i'm just waiting for tesla to rate their batteries in "horse power hour" instead of that lame ass Ah.

    • First Last

      First Last

      Ай мурун

      So you prefer it to be rated in horses instead of donkeys?

  • sery dfy

    sery dfy

    Ай мурун

    The numberless hail phytogeographically possess because sociology markedly hate than a upset panty. calculating, crazy timbale

  • abbatis34

    abbatis34

    Ай мурун

    The last time I was in Birmingham UK James watt factories still there and one of his engines.

  • Peter Smythe

    Peter Smythe

    Ай мурун

    Also based on the hilarious misunderstanding of physics most people who are obsessed with keeping the Horsepower alive have, I'm quite sure they're not multiplying by any conversation factors to get derived quantities. They're just using it as an arbitrary unit like golden aircraft carriers to measure the national debt or something.

    • GH1618

      GH1618

      Ай мурун

      It isn’t an obsession, just a convience. It is convenient to classify electric motors by Hp, particularly in the neighborhood of one Hp. Anyone with stationary shop tools, such as a table saw, needs to know the size of motor needed, and Hp is a convenient metric to use.

  • Peter Smythe

    Peter Smythe

    Ай мурун

    Also by far the better way to do metric horsepower would've been "0.75 kW."

  • Peter Smythe

    Peter Smythe

    Ай мурун

    Just. Use. kiloWatts!

  • Peter Smythe

    Peter Smythe

    Ай мурун

    "1 PS = 75 kgf*m/s"
    Sigh... Yet another poorly designed unit that isn't based on force but weight due to Earth's gravity...

  • Graham Rankin

    Graham Rankin

    Ай мурун

    Fantastic ! Thank you for this presentation. I was brought up (in Australia) using the imperial weights and measures system which I found confusing and antiquated as a student. Fortunately, Australia converted to the Metric System, starting in 1974, and I can't believe why the USA still clings to an outdated system of units for many applications. Your summary at the end of how Watts are in general use for electrical devices is an excellent example of how simple it would be if the USA made the switch to metric. If Australia could do it, why not the USA? Come on, join the rest of us.

  • Nick FB

    Nick FB

    Ай мурун

    We actually use kW here in Norway for cars for as long as I can remember 💪🏼

  • Davide Feroleto

    Davide Feroleto

    Ай мурун

    actually on every registration there are both values CV and kW or PS and kW

  • k1ndr3d

    k1ndr3d

    Ай мурун

    Are we just going to ignore the 1:64 fast and furious Eclipse?

  • Sherwood Friend

    Sherwood Friend

    Ай мурун

    The disparity between the quality of horse illustration and car drawing coming from an engineer. Did you date a horse girl in highschool?

  • True

    True

    Ай мурун

    I'll be honest, in Serbia we use kW as a technical standard, meanwhile HP can be heard from time to time in street talk/slang type of way. If that makes any sense. So for anyone that might find kW weird, to be honest it's much more cleaner and when somebody does actually give you a number you are able to determine the exact strength and feel for the power just by that. And it's easier to correlate other things in life with it. But i don't think that HP will ever change, nor does it need to, it became an iconic thing in the motorized industry, the best we can do is try to clean it up but still leave it as HP. Maybe like a new type of, more correct, horsepower? Oh-... yeah nvm that sucks sorry germans

  • Bruce MacKenzie

    Bruce MacKenzie

    Ай мурун

    I hear you but no hp no torque. Torque is merely gearing.

  • John Gilmer

    John Gilmer

    Ай мурун

    A strictly defined "horsepower" unit is just as useful as a "kilowatt" unit. It's just a matter of custom.

  • John Sekhar

    John Sekhar

    Ай мурун

    Brilliant! Where does our British bhp come in? Doesn't that take in the losses due to friction?

  • Jakee Clouse

    Jakee Clouse

    Ай мурун

    This is america and we do stuff that makes no sense. Pretty much sums it up.

  • Fck Uyo

    Fck Uyo

    Ай мурун

    My car can grind 50 tons of grain per hour.

  • Kalvinjj

    Kalvinjj

    Ай мурун

    A horse can make up to about 15 horsepower of peak power

  • russell bennington

    russell bennington

    Ай мурун

    hey you could use feet and inches too... just because everyone has different size feet

  • MossiTheMoosay

    MossiTheMoosay

    Ай мурун

    The metric unit for force is Newton (N), NOT kgf. I see the parallelism to lb and why it's okay, if you keep the difference of mass and force straight. It's just not used that way and it's unnessecarily confusing to use the same unit name for more than one thing.

    • GH1618

      GH1618

      Ай мурун

      The Newton is the standard unit for force, nevertheless kgf is a perfectly well-defined unit of force. He uses it here because it is convenient for his purpose. Like all good engineers, Jason is practical.

  • Chris Stiles

    Chris Stiles

    Ай мурун

    Ummm it's called horse power.... That's way cooler. Come up with a cooler name than watts and we'll talk. 😉

  • Sebastian Diaz Cota

    Sebastian Diaz Cota

    Ай мурун

    Yeah, but watts does not sound as cool

  • kz6fittycent

    kz6fittycent

    Ай мурун

    Sorry, I fell asleep. Can you start over?

  • Ben Garcia

    Ben Garcia

    Ай мурун

    No worries bro! It is not meaningless, education and learning is never meaningless. Your doing great and I love the videos! 😄

  • Tomislav Homan

    Tomislav Homan

    Ай мурун

    How come PI is also 3.14 in US, and not something like 5.23 freedoms per football field? :D

  • Metal Wafe

    Metal Wafe

    Ай мурун

    considering the sound of new EU Cars vacum cleaner isn't that far off to be honest XD....Nice Video, thank you for your work!

  • Nuovo

    Nuovo

    Ай мурун

    Fun fact: "cv" means "cavallo vapore", or quite literally "steam horse"

    • Bruno Pisca

      Bruno Pisca

      11 күн мурун

      Here in Brazil we say: Cavalo Vapor

    • Jan

      Jan

      Ай мурун

      sounds kind of like an item you could find at a restaurant :D

  • Stephen keller

    Stephen keller

    Ай мурун

    I’m gonna take a SWAG and say the 180 lbs force was an average he found amongst a variety of horses

    • GH1618

      GH1618

      Ай мурун

      More likely, he just used a typical horse of the type that was used for turning mills.

  • Christian O. Holz

    Christian O. Holz

    Ай мурун

    Germany as well as Australia have been transitioning to kW for some time now. It's actually required by law
    The whole imperial system of measurements the US uses is a joke as well as the Fahrenheit scale to measure temperature

    • GH1618

      GH1618

      Ай мурун

      The United States does not use Imperial units.

  • Caleb Knutson

    Caleb Knutson

    2 ай мурун

    I had a very similar discussion with my father except regarding impact forces from bullets. Here in the US we use ft-lbs to measure the impact force of a projectile. Yes ft-lbs, the same measurement that is used for torque is used for energy of an impact of a projectile.

    • GH1618

      GH1618

      Ай мурун

      Ft-lbs is energy (or work), not force.

  • Austausch Motor

    Austausch Motor

    2 ай мурун

    Actually, we should just use torque. Much more meaningful and conveys the behaviour of the car better for 99% of car buyers.

  • All My Hobbies

    All My Hobbies

    2 ай мурун

    but by that logic you need to admit the meter is just a made up distance that we call 1meter and 1kg is just a made up weight that is 1

  • quelorepario

    quelorepario

    2 ай мурун

    Well, when you have the only country in the world still measuring with
    feet... it doesn't seem that odd that they are using horses for power.
    Be glad they are not using birds for height.
    "How high is that?"
    "34 Condors!"

    • GH1618

      GH1618

      Ай мурун

      @quelorepario - Of course we use the Hp unit, but it doesn’t really have anything to do with horses. The unit was derived from an actual horse application as a means of relating it to human experience. On e the unit was set, the horse is no longer important. It’s about power, not horses.

    • quelorepario

      quelorepario

      Ай мурун

      @GH1618 "we?" really? From what planet are you from? We do still use HP in cars everywhere.

    • GH1618

      GH1618

      Ай мурун

      We don’t use horses. James Watt used a horse to set the scale for units of power. Today, it doesn’t have anything to do with horses. It is just a historical curiosity.

  • Gerry Baker

    Gerry Baker

    2 ай мурун

    Please do a video on Torque, which I am told is a much better means of asessing performance. Thanks, G

  • Bruce Schneider

    Bruce Schneider

    2 ай мурун

    So, you're saying that the HP unit is a dynosaur?
    Thank you, thank you, I'll be here all week. Be sure to tip your waitstaff.

  • IC 680

    IC 680

    2 ай мурун

    How dare you. If trump was still in power this would be a deportable offense

  • Max Xenon

    Max Xenon

    2 ай мурун

    James what?

  • Patrick

    Patrick

    2 ай мурун

    In civilised countries, cars are measured in kilowatts for power, and Newton/metres for torque. I don't know what a foot/pound is, and I use horsepower when talking about cars because it's still a convention in colloquial speech. Honestly torque is more important, and metric is far superior. The math is so much easier and more accurate. Imperial is just a collection of poorly thought out and outdated units that have no relationship to each other, collected together over a long time, with a whole host of numbers like 3, 4, 8, 12, ect ect, as well as completely random numbers that make the math very difficult, and memorising a lot of formulae impossible for people who aren't turbo autists. Honestly it's holding average Americans back, and education is to blame mainly. The education system could be teaching metric. Americans are also in denial about metric, metric is everywhere in America already. The rest of the world adapted a long time ago. The UK, Australia, New Zealand, South Africa, Canada ect ect used all imperial units up until probably the 60s. We changed our currencies to decimal, and the switch to metric happened quickly without any fuss. What Americans don't seem to understand is that there's no learning curve with metric.

  • Moe Dani

    Moe Dani

    2 ай мурун

    I watched the whole video waiting for that last sentence. Merica

  • Gary Lee

    Gary Lee

    2 ай мурун

    Thank you for explanation ! You managed to turn confusion into clarity. You are exceptionally good at this.

  • Erik Sands

    Erik Sands

    2 ай мурун

    For those of us in the US, if we accept watts are the better way, can we also go with metric units across the board? I'm terrible with arithmetic and this would make me less terrible (so selfish in this request, I know).

    • GH1618

      GH1618

      2 ай мурун

      You are free to use whatever units you like. Both metric and US Customary units are legal in the USA.

  • Icky

    Icky

    2 ай мурун

    so how did we come to the conclusion that an engines hp is equal to torque x rpm / 5252?

    • Redtooth 75

      Redtooth 75

      2 ай мурун

      Power is torque times angular velocity. If you want to measure power in horsepower, torque in ft*lb, and angular velocity in rpm then you need to do unit conversions to get everything to work together. All of the unit conversions give us a final formula of (torque X RPM)/5252

  • Glenford Burrell

    Glenford Burrell

    2 ай мурун

    Could someone explain BHP?

  • Lasha Barblishvili

    Lasha Barblishvili

    2 ай мурун

    Agree with you! Also you should use a metric measurement system in USA instead of feet and inch, such kind of systems are really complicated ;)

  • Michael Webber

    Michael Webber

    2 ай мурун

    They're lamps not bulbs, bulbs grow in the ground

  • MCR71

    MCR71

    2 ай мурун

    Man you are great. Thanks for all your excellent explanations

  • Superman 68

    Superman 68

    2 ай мурун

    Horsepower: a universally agreed upon unit of power in 2021 equal to 550 ft*lbs per second, which is equal to 745.6 watts.
    Ignore previous types of measurement derived from Mr Watts and his initial tests with horses. These were crude, early measures that have been refined and improved over time.

  • Selenium Glow

    Selenium Glow

    2 ай мурун

    Well, what is brake horse power? Is it different from the Horse power you talked about right now?I see this here in India a lot (along with the metric KW units) for bike and car engines.

  • Miles Rains

    Miles Rains

    2 ай мурун

    I'll admit to being uncomfortable with kilowatts because--at least in America--that's usually a measurement of electricity at work. But my therapist and I are making progress.

  • akhtar razzan

    akhtar razzan

    2 ай мурун

    kWh : kilowatt hour, is the measurement of energy
    kW : kilowatt, is the measurement of power

  • Domingo

    Domingo

    2 ай мурун

    Why not use firepower based on how much heat is generated, I say this knowing full well about the temperature conversion process? Firepower sounds cool & if the math figured out then ... idk not a scientist or an engineer! Let me know what you think would love to hear it!

  • adfaklsdjf

    adfaklsdjf

    2 ай мурун

    Jason, let's do this.. strike down HP.. start speaking in kilowatts.. I will join you.. we can defeat the others!

    • GH1618

      GH1618

      Ай мурун

      Jason is a practical person, not a missionary, it seems to me.

  • muhammad nasif

    muhammad nasif

    2 ай мурун

    Kilogram force lol..you mean Newton?

    • GH1618

      GH1618

      2 ай мурун

      Not the same. A Newton is the force that accelerates a 1kg mass at 1m/s^2. Kgf is force on a 1kg mass in standard gravity, which is 9.81m/s^2.

  • Jaroslav Kalivoda

    Jaroslav Kalivoda

    2 ай мурун

    i am curious how many Americans really wached it till end.

  • sickandloose

    sickandloose

    2 ай мурун

    This is america always wanting to be different

  • Jason Berg

    Jason Berg

    2 ай мурун

    The ending was epic, felt like an ending of a Monthy Python movie

  • Jacobs 322

    Jacobs 322

    2 ай мурун

    In Europe every car has had both horsepower and kiloWatt number as long as I can remember, I'm only 20 tho

  • R M

    R M

    2 ай мурун

    You do a great job explaining things well spoken

  • Joern Lindstaedt

    Joern Lindstaedt

    2 ай мурун

    Maybe for Europe we should use 1 Horse power = 1 Donkey power to avoid confusion 🐴 or... everyone just uses metric instead 🤓

  • Dan New

    Dan New

    2 ай мурун

    I'm actually gutted James Watt didn't have a donkey strapped to that mill for his experiments.....because then we'd all be bragging about our cars' ass power, & that would be hilarious.....& I need to get out more.

  • kevin9c1

    kevin9c1

    2 ай мурун

    Two comments.
    1. The HP to PS conversion is largely responsible for people walking around saying things like "the US version of the car had slightly less power than the European version because of some reasons." Sometimes yes. When they are off by about 98.6%, NOPE!
    2. kW is fine but with electric cars, we have the kWh to manage (energy) for the battery, then kW for the motors themselves. This is another layer of complexity for people.

  • Αλεχιοσ ξομμυνιστ Βρεακερ

    Αλεχιοσ ξομμυνιστ Βρεακερ

    2 ай мурун

    well i used to think horse power = pull force from one horse hahahaha
    700 hp= 700 horses pulling the car, that'll be really fast

    • GH1618

      GH1618

      Ай мурун

      The fallacy is that before you get anywhere near having 700 horses, most of the mass is horses, so most of the work is moving the horses. Another fallacy is that horses can only go so fast. More horses won’t go any faster.

  • Αλεχιοσ ξομμυνιστ Βρεακερ

    Αλεχιοσ ξομμυνιστ Βρεακερ

    2 ай мурун

    i mean it, thrust/weight ratio is the most precise measure for performance.

  • Julien B

    Julien B

    2 ай мурун

    Well in Belgium, legally like for taxes or insurances, cars are measured in kw

  • Akshit kubadia

    Akshit kubadia

    2 ай мурун

    Yes but then you need to remember the formula to convert bhp to kilowatts and visaversa

  • Simeng Fu

    Simeng Fu

    2 ай мурун

    How about donky? Or mule... Donkypower !!!
    "how fast is your engine?"
    "Oh, not that fast, only 160 donkies. But, according to the specs, it has 450 mules...."
    "You could do some serious towing with it then"

  • Ronald Garrison

    Ronald Garrison

    2 ай мурун

    After all this, I'm thinking of that wine in my fridge, and how close 750 ml is to a "fifth."

  • Ronald Garrison

    Ronald Garrison

    2 ай мурун

    What really sucks is mixing SAE and metric units—for example, expressing an EV's efficiency in terms of "kilowatt-hours per mile." Grrrrr.

    • Ronald Garrison

      Ronald Garrison

      Ай мурун

      @GH1618 I don't care if they're both common, it's just goofy to mix units from two different systems.

    • GH1618

      GH1618

      Ай мурун

      KWH and miles are both common units in the US, so it makes sense to us. If you want to use km, it’s a trivial transform.

  • Ronald Garrison

    Ronald Garrison

    2 ай мурун

    Horsepower is named after Watt! Geez.

  • Gary Paisley

    Gary Paisley

    2 ай мурун

    You've never ridden a horse?

  • Money&Stuff

    Money&Stuff

    2 ай мурун

    Actually we use kw in europe alongside hp. And when you are ordering parts, they always ask you how many kw is your engine

  • Nick S

    Nick S

    3 ай мурун

    Boats that take outboard engines routinely have both HP and KW stamped on their manufacturer plate, so KW is not unknown in the boating world....

  • Mocanu Octavian43

    Mocanu Octavian43

    3 ай мурун

    I use hp and nm because they are more accurate

  • Eric Ozbun

    Eric Ozbun

    3 ай мурун

    In Italy your car's registration paperwork has the car's power expressed in Kw, and every document states power in Kw ;)

  • Adrian Untalan

    Adrian Untalan

    3 ай мурун

    Watt invented the horsepower unit... The irony is still fresh years after learning it in school.

  • Adrian Untalan

    Adrian Untalan

    3 ай мурун

    When you actually have to do complex calculations, the simplicity of derived Metric units like *"Watt"* definitely simplifies things a great deal. You never have to memorize anything and you can usually get by with logical analysis.

  • Tristan Laing

    Tristan Laing

    3 ай мурун

    What about BHP - break horse power - seen it in UK magazines like "practical classics". What's that about?

  • svendsen1111

    svendsen1111

    3 ай мурун

    @Engineering Explained - at the very end: “Thank you so much for WATTching” ... i see what you did there! Informative video that makes me learn, as always. Hope you are well. Cheers from Denmark

  • Andrew Sharicz

    Andrew Sharicz

    3 ай мурун

    Oh man the light bulb is such a bad example to use....and a CF bulb at that. I guess it's the best of what there is to relate to.

  • Simon Prescott

    Simon Prescott

    3 ай мурун

    So one kw is a Belgian draft horse? Or a stallion??

  • ACPushkin

    ACPushkin

    3 ай мурун

    A little known historic fact is, that the unit 'Watt' was not named after James Watt himself, but instead was named after his paternal grandmother. If you want to find out more about that, just google 'wat grandma' :-)