What Does Horsepower Really Mean

[SetterDog]

If I remember correctly ......... Mechanical horsepower is the ability to move 550 pounds one foot in one second. So a 20 horsepower engine would move 11,000 pounds 1 foot in a second.

 

[bcp]

Two horsepower with good traction.

Bruce

 

[Hay Dude]

Brake Hp, PTO Hp, drawbar Hp, horsey Hp, all the same. It's the transmission package that changes.

Yes, but the transmission is a huge part of the tractor package.
Drawbar HP is measured at the end of the drawbar, taking into account losses through the driveline. Brake HP is at the flywheel and does not take transmission into account. So they are not the same.

When buying a tractor, on the back end I want to know:
1. how much it will “drag” across the ground.
2. how much power is available at the PTO to run my baler, or whatever the user is running. (baler, sawmill, snowblower, etc)

IMO, on the back end of a tractor, what is most important is pulling power (drawbar HP) and PTO horsepower.

Here is the “Tests” page

On the front end (if loader equipped) what is most important is the lifting power of the hydraulics and the front axle capacity for carrying a load.

Any tractor buyer should consult Tractor Data and pay special attention to the “tests” page. Here you can compare what your tractors will actually do.

TractorData.com CaseIH MX270 Magnum tractor tests information

www.tractordata.com

****Unknown/unsupported brands aside, I urge all of you to stop buying “brands” and start buying “tests” when you come up with your lists of comparable models.****

 

[bmg88201]

After reading all this I now have a headache and am confused. Gonna have a cup of joe and laugh at today‘s Far Side cartoon.

 

[YanmarFever]

Ok guys, lets cut out all the fat and get down to the facts.

Horsepower is measured by $$$ money yes money.

The more horsepower you buy the more it costs your wallet.

Its really quite simple Horsepower = $$$$$

 

[5030]

It's really quite simple.

Disclaimer: I'm a retired nuclear reactor operator and dealt with thermodynamics and power conversion for 38 years.

You need to have a delineation between the theoretical word and the real word. What I mean by that is, in the link I provided below, there is reference to moving a load over a certain distance over a certain time. This negates any friction or other resistance. In the energy conversion process, you end up with the same energy that you started with before you even started to move the load. It's just spread out with generally 30% of the energy moving the object and the rest to the environment. Google "Conservation of energy".

Ok, maybe it's not so simple. So simply more horsepower, the faster you can move the load.

(don't get turned off that link comes from an auto manufacturer)

What is Horsepower and Why Does it Matter?

Being a retired steel hauler, torque is important, not HP, which is why I like Cat's. Excellent torque rise at low RPM. Hard to beat a mechanical 3406. Far as tractors go, with me it's PTO torque 'cause most times I'm running powered implements and most require lots of power.

 

[5030]

Two horsepower with good traction.

Bruce

Once the tires loose traction, you are done.

 

[sd455dan]

Being a retired steel hauler, torque is important, not HP, which is why I like Cat's. Excellent torque rise at low RPM. Hard to beat a mechanical 3406. Far as tractors go, with me it's PTO torque 'cause most times I'm running powered implements and most require lots of power.

Given equal rated HP engines for a tractor I will chose the one with Lower RPM for the same rated HP.
That means a Higher actual Measured torque.

Which generally is the heavier weight, Larger physical dimension engine which has a heavier crankshaft, pistons, and rods.
IMO these newer CUT tractors have decreased the mass, Increased the RPM of the diesel engine to achieve the rated HP.

 

[5030]

Unlike Hay Dude, all of my hay tools have skid shoes on them (that I keep hard rodded) so frictional losses are minimized. They all pull easily. The power is used to drive the mechanisms, not drag them. I hard rod everything including all my buckets too. Used to SMAW them but now I use Lincoln Innershield flux cored wire. It ain't cheap and requires serious amperage but it's quicker and little spatter. Spray arc only.

 

[edgarrian]

I understand hp is derived from torque, and remember Horsepower = Torque x RPM / 5,252
If you see a hp/torque graph for an engine, from 1 to 10,000 hp the two curves cross at 5,252. At that rpm hp=torque.
You have to be older to remember the great Smokey Yunick (we met him years ago at his shop in Daytona. He said if you look at two motor graphs, I'll take the one with a flatter curve. Motorcycles for example may rev to the moon but hp is "peaky".
I pulled our farrier's Dodge Ram 3500 diesel out of a ditch last winter in the snow with my 140hp F-150 six cyl.4x4 pickup 4 speed farm truck. It's geared low and has a granny 4x4 low 1st gear. Just above idle...probably 4mph.
If you connected my 14hp 1cyl. Economy tractor to my two Cub 24hp 2cyl mowers it would drag them wherever you wanted.
Watch this...probably 100:1 ratio of horsepower difference and 100+ years apart!

weight has a lot to do with this as well. How much does the john deere weight in comparison to that old steamer?