Horse Power for dummies.......

Hey folks,
I'm a littlelot thick headed here.

2 tractors (IHC and Deutz '64 and '65) 1 with 3 cyl Diesel 1.8 liter 26hp and the Deutz has a 2 cyl 1.6 liter air cooled diesel with 29hp. Deutz (actually a Kramer, but the motor is Deutz) is a little smaller than my IHC, not near as heavy, and much weaker.

Guess there's just some things that I ain't sposeta understand...........

Dave

There is HP and then there is torque rise, flat torque or torque drop when lugged below rated rpms.
Torque and HP are something that is often miss understood here and elsewhere.
People talk about torque is what gets a load up a hill........Well the machine with the most HP carries the heaviest load the farthest and fastest.

your relating the size of the engine to horsepower, it is a factor, but engine size is not the deciding factor, compression, valve size, cam profile ect can easily make a smaller engine out hp a larger one, the big question for a tractor is which one has the most tourque, usually its the bigger one

Its easy,torque is what does the work, without torque you cant do anything.hp is how fast the work gets done ,the more hp the faster you work,aint that simple?lol.. this is true whether your working a horse,a tractor,or a aa fuel dragster.your 3cly has more torque,therefore more pulling power.the 2cyl has more hp but less torque so less pulling power.its like putting a 25 hp briggs in your tractor,might run but wont pull,however if you put a 25hp tractor engine in it it works.hp and torque are two totally different things.by the way,ever wonder why most old tractors run at 2000-2500 rpm?thats right in the middle of the torque curve is the answer.this is true of ANY 4 stroke gas powered engine by the way.torque falls off at higher rpms,while hp continues to increase with engine speed.thats just the nature of the beast.

Displacement, compression ratio, and volumetric efficiency are the major design parameters that determine max horepower.

Horsepower is nothing but a calculated number based on torque and RPM, which is a yardstick to measure work performed. Torque actually moves the load. You can have many different HP ratings for the same engine by varying the RPM- which is a way to get around the 50hp mark on compressors & such that is part of the newer regulations- just derate the engine by setting the governor down. John Deere even has nice directions on their website. A 315 and a 350 Cummins are basically the same unit, but the 315 only turns 1800 RPM instead of 2100. A D8 CAT "only" produces around 300hp, but lots of torque- and it turns pretty slow, so the calculated "horsepower" is low

UH what speed do the engines run?

Smaller engine can get higher horsepower by spinning
faster.

Also are they turboed? What the other guys said
also but I am betting the smaller engine runs more
RPM's than the bigger one.

I always remembered when I put a 10' wheel disk behind our "53hp" 4wd Kubota and was quite unimpressed. Thought maybe the soil conditions were being a little unfair to the little guy, so I hooked up my tired 40some hp Farmall M. Obviously the M walked the disk a lot better even being supposedly "10hp" short. A lot more displacement and a lot more torque.

MeanGenel is the closest to the truth of the buch of you. Sorry but the rest of you guys completely failed math and physics class.

1HP electric motor = 1HP water turbine =1HP two stroke gas = 1HP four stroke gas = HP gas turbine = 1HP turbo diesel =1HP Clydesdale.

In your discussions you are comparing apples and oranges.

HP = lb ft torque X rpm /5252

Another example is a Farmall 140 regular horsepower is about 25 HP, but with a different governor installed can put out 40 HP.

At 40 Hp the engine wears out quicker due to the higher rpms.

B&D, you might be right mathmatically speaking, but replace that 1 hp electric motor with a 1 hp Briggs & Stratton engine. Big difference in torque...

But hp is the amount of work being done. More hp does more work.

Out of curiosity,two engines of the same displacement and similar design, the V8 produces more power but the 6 cylinder produces more useable torque.To shift a heavy load the farthest and fastest requires torque not just horsepower.A Formula 1 engine produces a lot of power and torque, but it won't shift a load fast or very far.

The difference comes from the various duty cycles offorded by their design. HP = the power required to lift 33,000 lbs a distance of 1 ft in one minute. Given the right combination of gears and/or pullies , any one horse power unit will do this once. That's only one minute of work. A certain power unit may only be able to do this for 5 min , another 10 hrs , and still another indefinately before mechanical failure. But they all had one hp and that means they only have to be able to do it once to get that rating. Some may have to turn 5000rpm to achieve that 1 hp. Some 500 and some 2200. How long do you think a 1hp model airplane engine running 10,000 rpm will last lifting 33,000 lbs a foot a min for 10 hours? It's actually such a misleading and meaningless measurement of true ability that it should be outlawed as a measurement of comparison between products. Max torque is all that matters. It peaks at an rpm governed by the volumetric efficiency of the engine and /or the design parameters of any power generating unit. You cant just add rpm to get more. Max is max. Any engine / motor should be run at the max torque rpm and use gears/pullies or hyd to achieve the required results. There are a lot of 45 hp JD "D",s still going strong after 65yrs of heavy work. How many 45 hp Kubota,s will even make it half that long?? It ain't about horsepower , and never was.

How are the two machines rated? Engine, PTO or drawbar horsepower? If you're comparing PTO and engine horsepower, you're comparing apples & oranges. Also, I believe engineers in the US and Europe use different standards to rate engine horsepower: SAE versus DIN. And the test protocols have evolved over the years so you really can't compare SAE horsepower from, say 1970 to an SAE rating in 2010..

A heavy tractor with a flat torque curve is going to win out over a light tractor with a peaky torque curve, even though they produce the same PTO horsepower.

You guys are missing the point again with apples and oranges comparisons.
The Briggs is 1HP max no more.The electric motor is 1HP continuous and 2HP peak.
The electric motor will easily make 2-1/2 times rated torque and about 2HP on the shaft when lugged.
Of course the 1HP electric motor will keep turning when the 1HP Briggs stalls with intermittent overloads.
Lets see how long it takes for the smoke to leak out of the windings when running continuous at 1-1/2 to 2HP.

Similar goes for so called "lugging power" which is actually "torque rise" when a reciprocating engine.
When it's lugged from rated HP rpm where the engine is moving the max cfm of air through it per minute. The engine at the point is operating at reduced volumetric efficiency.
Torque rise occurs as engine rpms drop to peak torque rating. When the engine now pumps max cfm per intake stroke.

all engines gain hp as they spin faster,highest rpm, highest hp,torque curve falls off,hp continues to climb.