Is 50 HP really 50 HP?

[Texasmark]

Branson sub compact brand has at least one tractor listed on the Nebraska Test Results sheets. So yes they do include current edition sub contacts. Haven't checked other brands.

 

[Texasmark]

Comparison between a steam turbine and a reciprocating steam engine comes to mind here as an example .

In taking a quick look at US navy aircraft of WWII and later, comparing the radial piston engined Grumman F8F **** cat with 2250 hp, 7650# empty wt, 455 mph max speed and the later Grumman F9F turbojet with 8500 ft-lbs of thrust, 11,866# empty, and 647 max speed it is interesting that they (the planes) are in about the same sized (L x W) package but you get a lot more performance from the turbine. Course variables exist like shaft losses and blade efficiency and all that but assuming designers gave it their best shot at the time, it's an impressive difference.

Course fuel consumption would be an interesting parameter to look at using 100+ octane AV. gas vs JP-4? (Kerosene) and price per gallon. Guess one could look that up if all that interested.

 

[farmer2009]

Example: My 5075E is sold as a 75hp tractor (engine, under who knows what ideal test conditions) , but put that engine in the tractor and it can only deliver about 64 hp to the pto (and I assume the tires too) according to Nebraska tests.

Not necessarily on the drawbar hp. Your specific tractor wasn't tested for drawbar but I have one that I know was. Here's a screen shot.



Massey Ferguson 255 50 pto hp and 42 drawbar hp. Engine wasn't tested. But I believe you will find there is almost as much power loss from drawbar to PTO as there is PTO to engine.

 

[farmer2009]

Another example of drawbar being less than PTO.

Sorry only one picture per post.

 

[Retiredguy2]

Respectfully, I think you might be missing his point. The poster means the pto horsepower rating better represents the horsepower that is available to the Pto, or the pulling wheels, hydro pump, etc..; this is a better measure of the tractor's available power than measuring the engine under ideal conditions on a bench test.

I agree with you on this 100%, reading this thread made me recall when back about 1973 car makers began rating engines at net horsepower. I purchased a 1973 Chevy with a 350 2-V and it was rated at 145 horsepower, the prior year's same engine was rated at about 250 horsepower. To me PTO horsepower is a more accurate way of what a tractor engine is capable of producing.

 

[TSO]

Another frustrating aspect is that most brands also take the same engine, and tweak the fuel delivery amount to add or subtract HP, then charge you more for the higher HP. For example, the 1.8L Turbo'd diesel in the Kioti NX4510, 5010, 5510, & 6010 all use the identical engine, and the HP numbers are changed with fuel & computer settings. The 3.0L diesel in my Massey 1652 is identical for the 1655 & 1660, but these are all naturally aspirated, and is literally adjusted only by a fuel pump setting (very easy to adjust the set screw on these).

Kubota, LS ... They all do this.

 

[Gary Fowler]

Another example of drawbar being less than PTO.

Sorry only one picture per post.

View attachment 449640

Drawbar HP is always much less than PTO or Engine HP. It is the final result of pulling power put to the ground from the engine which takes into account tractor weight and all the power losses from engine to tires on the ground.

Comparing CUT Drawbar HP to Utility farm tractor DB HP would be like comparing the HP of a rail dragster to a tractor. A 2000+ HP dragster couldn't leave the starting gate if attached to a 40 HP CUT, there just isn't enough traction in the light frame of a dragster to put all that HP to use as a pulling machine.

 

[buickanddeere]

In taking a quick look at US navy aircraft of WWII and later, comparing the radial piston engined Grumman F8F **** cat with 2250 hp, 7650# empty wt, 455 mph max speed and the later Grumman F9F turbojet with 8500 ft-lbs of thrust, 11,866# empty, and 647 max speed it is interesting that they (the planes) are in about the same sized (L x W) package but you get a lot more performance from the turbine. Course variables exist like shaft losses and blade efficiency and all that but assuming designers gave it their best shot at the time, it's an impressive difference.

Course fuel consumption would be an interesting parameter to look at using 100+ octane AV. gas vs JP-4? (Kerosene) and price per gallon. Guess one could look that up if all that interested.

Comparing the prop to the jet is apples and oranges. A piston prop engine compared to a turbo prop would be reasonably close. The "small" body PT6 turbo prop replaces the 1340 P&W radial on the Otters. Lbs of fuel per hour is higher but the fuel is cheaper. Maintenance consists of checking the oil level and a general visual . Usually a higher shaft HP turbine is installed. Most reassuring when taking off heavy from a short lake. No worries about the 1340 floating a valve, knocking a cylinder head off and covering the windscreen with oil.

 

[MessickFarmEqu]

running though a Nebraska test costs over 100k for each model, that's why you don't see more listed.

any dealer would own a Dyno and can hookup and test a tractor for you. It would be very unusual to see a machine not meeting or exceeding what its rated for.

its much easier to 'cheat' the spec sheet on loader lift specs because of all the measuring points and weird geometries than it is to mess with HP numbers.

 

[Industrial Toys]

Who could blame one for believing nothing anymore. I once saw a shop Vac with 5 (or was it 6) HP sticker. It had 110 volt 15 amp plug. You can figure about 737 watts per horsepower. You can get about 1700 watts from a normal outlet so how did they get 5 or 6 hp? Maybe it had a free energy collection system.

Anything to fool and fleece the consumer.