What Does Horsepower Really Mean

[JasperFrank]

I am somewhat suspicious of this since the tug IS pulling the truck off the dock at the beginning of the contest, but then the tug gets a bit sideways: Yet it is a fun Vid.

 

[Hay Dude]

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.

I was semi-interested in a new Deutz-Fahr 140HP tractor last week, but the engine is only 4L and IMO, longevity and torque at low RPM would be questionable.
Although if anyone could figure out a way, it’d be German engineering.

 

[4570Man]

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.

Are we vertically lifting the 550 pounds which seems like the easiest to replicate measurement or dragging it? If it’s dragging it does it have wheels or skids?

 

[4570Man]

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

Weight and traction wins tug of wars. HP doesn’t really matter. Without increasing traction you could increase the hp by 10x without a big difference in the outcome. This is weight and traction at work. Think a pickup with 2x the hp could chain up and drags it?

 

[4570Man]

I am somewhat suspicious of this since the tug IS pulling the truck off the dock at the beginning of the contest, but then the tug gets a bit sideways: Yet it is a fun Vid.

There’s a lot to consider in that video besides just hp. Props aren’t as efficient as wheels for utilizing input power to start with. The truck weighs a lot more than the thrust that the boat can make. As with any tug of war the tow line should be level to really demonstrate anything. With so much elevation gain the boat is pulling the truck downward which increases the friction between the tires and the road. If the line was level the boat probably could have won. Also they obviously didn’t want to pull a million dollar truck in the ocean so the boat never had any chance of “winning”.

 

[BnRidge]

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.

Power transmission (transmitting power) includes far more than gear reduction, or a driveline, or drawbar. Power can be converted from many forms to many other forms - electric, electromechanical, mechanical, fluid, heat, with many different units of measure. In the end energy is conserved, so adding it all together will result in same power regardless. Maybe "transmission package" would be a little vague and misleading, but it has very little to do with shifting gears. How many BTU/hr does it take to pull a plow. I like looking at combines - one power source, so many ways to transmit power, and none of them include a drawbar.

 

[JasperFrank]

Horsepower = Torque x RPM / 5,252. The problem I have always had with this equation is the RPM component and how that is "fit in to" the equation. RPM and the division by 5,252 seems to be entirely unneeded. Torque is the one and only value that needs a measurement. HP can be anything you want it to be if the RPM is just set at any arbitrary value. Friends and I, discussed this for over 20 years on a Speed Boat site. HP just didn't make sense as any meaningful rating of power. A Saturn 5 rocket, on launch is said to have had 32 million horsepower. What does that even mean?

 

[sd455dan]

Horsepower = Torque x RPM / 5,252. The problem I have always had with this equation is the RPM component and how that is "fit in to" the equation. RPM and the division by 5,252 seems to be entirely unneeded. Torque is the one and only value that needs a measurement. HP can be anything you want it to be if the RPM is just set at any arbitrary value. Friends and I, discussed this for over 20 years on a Speed Boat site. HP just didn't make sense as any meaningful rating of power. A Saturn 5 rocket, on launch is said to have had 32 million horsepower. What does that even mean?

Right
HP to me means rate of work that can be done over time. Just a calculation
Torque being the resultant moment of force applied at a distance or basically its measured twisting force.

On the Saturn V 7.6 million lbf seems to convey more meaning than the HP
That said can't wait to see the launch of SpaceX Starship with it's 17 million + lbf.
Being able to lift over 100 tons of payload into space will be a Game changer

 

[bcp]

A Saturn 5 rocket, on launch is said to have had 32 million horsepower. What does that even mean?

Obviously, it means 32 million horses could have pulled it into orbit. And instead of so much pollution, the horses would produce useful fertilizer to grow more hay to fuel the next launch.

Just like two horses on a buggy can pull it twice as fast as one horse.



Bruce

 

[Fuddyduddy1952]

From what I looked up a healthy human is about 1.2 hp, athlete can be 2.5 hp. Next time I'm using my Weedeater I'll think about it has more power than me.