Can someone explain this Nebraska test

[Fritz Maurer]

This is test number 1243... the
Ford 9700. Im not understanding why they claim nearly 9 gph at 113 drawbar horsepower... that means it would run less than 5 hours on a full load of fuel. In the field it will run 14-1/2 hours, as read on the tachometer, pulling 6-16s in clay loam. I dont understand what horsepower hours are, maybe they figure into this as well. I also dont understand the gear positions, neither 8 nor 5 are in low range; I cant believe that they can get 113 at the drawbar in any of the upper range gears. Thanks, Fritz

 

[wore out]

What are the horsepower hours per gallon, should be between 13 & 17 for a diesel.

 

[jon f mn]

The Nebraska tests frequently differ significantly from real life.

 

[bjb in TX from Ne]

You need to keep in mind what HP is defined as, especially wrt the Nebraska test. Its Force X Distance / Time (work) (Specifically if I recall on HP is 550# lifted vertically 10 ft in 1.0s).

If we assume for a moment fuel consumption is directly proportional to the amount of work you do with your tractor, in theory you are only using about 1/3 the capacity of your tractor based on your numbers (fuel lasts 3x as long). So to pull 6-16s in your soil, at your preferred speed, you are only using roughly 40hp (3gal per hour) at the speed/depth/setting/etc that you pull your plows. If you could generate enough traction, you could pull 18-16s (again in theory with this highly simplified example) with your tractor. If you look at the 50% power in 11th gear, the power is about half (65hp) and so is the fuel consumption (4.7gal). Because power curves are not linear and bigger tractors have better traction and difference in engine speed and gear ratios, a 40 hp tractor may not be able to pull those plows as efficiently as the larger one running at a partial load.

The important thing with the Nebraska tests is they are standardized, so you can directly compare a Ford to an IH to a JD to a ???, and buy a tractor according to your needs and conditions.

 

[thehickdaddy]

test 1243 says 8.975 gal per hour because that is how much it was drinking under full load. full of weight and ballast on a hard dirt track. or by that year it might have been surfaced. no tractor in the field can run fully loaded all the time. there is always hills, or corners, or anything to cause lack of traction or the implement to decrease in depth.

take test #296 for example for 1938 graham bradley. test B is 100% maximum load for 2 hours. Average fuel use 3.083 gal per hour. My grandpa and family used the identical tractor for decades. I have years of fuel and grease ledger books for the custom farming business. My grandpa never hit 3 gal and hour mark. He never hit 2 gal. He averaged 1 1/2 gal an hour. He said between the headlands and odd shapes of fields with trees and streams, there was always time with implement out of the ground, or simply driving to and from fields. Or field was muddy or slippery causing lack of traction.

Also on the same test, check out test G, drawbar test in each gear. 2nd gear produced more horse power then first gear, and 3rd gear makes more then 2nd due to wheel slip. Horse power is math between work and time.

I was at a tractor show over the week end and as always, i hear the remarks in the crowd, oh look at how much more power the john deere had then the Oliver! and i might interrupt and say, nope, did you see how the john deere took over twice as long to make it down the track? horse power involves time. the tractor pulling a slightly bigger load but takes more then twice the time to accomplish, is the less horse power tractor

check out test #480 for Case LA

draw bar test G again, develops 40 horse power in first gear but with 15.76 percent wheel slippage, it could not hook up and get traction
but develops 46.73 horse power in road gear with only 2.9 percent wheel slippage. lots of math, lots and lots of math
J I Case LA nebraska test 480

 

[thehickdaddy]

graham bradley 1938 nebraska state test
graham bradley nebraska state test 296

 

[ss55]

Figure one PTO-HP equals around .85 drawbar-HP. Check the test to see if the PTO test was around 130 PTO-HP and 15 PTO-HP/gallon of diesel fuel.

Compare this test report to other contemporary tractor tests.

In real life even heavy plowing work ranges between 80 to 100 of maximum capacity and up-time varies between 70 to 90 percent of the time in the field.

Nebraska Tractor tests were run on a circular concrete track.

 

[Traditional Farmer]

X2

 

[560Dennis]

Interesting

 

[MarkB_MI]

In the real world, you're not going to be able to operate continuously at maximum drawbar horsepower. But the Nebraska University testers can do that with specialized equipment. In your real world operation, you're probably running at around 75 percent of that 113 horsepower. And at 75 percent, they saw about 8 gallons per hour.

The reason they rate the maximum drawbar horsepower in a fairly high gear is slippage. There's less wheel slip the higher the gear, because there's less torque on the wheels. In 8th gear, the slippage was only 7 percent, while in 5th gear it's a whopping 15 percent! I assume you pull your six-bottom plow in a fairly low gear, so you're getting a lot of wheel slip. Because of wheel slip, the tractor is not able to get its full horsepower to the drawbar. So it burns less fuel than it would at 100 percent of horsepower. So I'd say wheel slip accounts for most of the different between the Nebraska test results and your real-world experience. Should you do something to reduce slip (e.g. more ballast, wider tires or duals), you'll probably see an increase in fuel consumption.

 

[560Dennis]

Was that engine the Chrysler industrial engine ?

 

[560Dennis]

Is that a Ford engine ? Or a Perkins ?
Were they made in the UK ?
Im getting little off the subject ,but I was told the European engines were way better on fuel than USA .
With check other tests of US mfg. . At the time to see what there test results were to have a bench mark to compare them .

 

[BarnyardEngineering]

75%? I would dare say you are more likely averaging closer to 50%, even plowing.

 

[WNYBill]

My AC6060 is rated at 4 gal per hour in the Neb. test and about 2 gal per hour when I worked it. However, my Kubota (Fiat) 7030 is rated at 4 gal per hour in Neb. test and I use about 3 gals. per hour when I work it. I am using the same equipment. The 6060 was much more efficient, at $6.00 per gal. I can see it. The AC had a turbo, the 7030 does not, I presume that makes the difference.

 

[RodinNS]

The simple answer is that in the field, you're not running at full power, or anything close to it most of the time unless you're running a chopper or something. That test is full power, 2100 rpm for hours and hours. Most of the ford transmissions, and probably most others for that matter have their lowest parasitic losses in the higher gears. That one is probably in 6 low... so they just find the sweet spot where the tractor can get hooked to the ground and make full power. Lower gears you can get a lot more torque but once you start to spin, power transmission declines...
To give you an example... I run a Ford 7710. If I want to rake hay with it... it'll burn 2-3 gph. On a discbine or chopper... 5 is normal. Other utility work, spreaders, even plowing... usually 3-4. However, I've used it on a vertical tillage tool that I was dragging in 6 low which is 6-6.5 mph. That runs right at 7 gph. 6-7 hours flattens both tanks. So in that example, it made a good deal more than rated power, nearly continuously for 7 hours.

Rod

 

[wore out]

(quoted from post at 09:51:56 08/03/22) The simple answer is that in the field, you're not running at full power, or anything close to it most of the time unless you're running a chopper or something. That test is full power, 2100 rpm for hours and hours. Most of the ford transmissions, and probably most others for that matter have their lowest parasitic losses in the higher gears. That one is probably in 6 low... so they just find the sweet spot where the tractor can get hooked to the ground and make full power. Lower gears you can get a lot more torque but once you start to spin, power transmission declines...
To give you an example... I run a Ford 7710. If I want to rake hay with it... it'll burn 2-3 gph. On a discbine or chopper... 5 is normal. Other utility work, spreaders, even plowing... usually 3-4. However, I've used it on a vertical tillage tool that I was dragging in 6 low which is 6-6.5 mph. That runs right at 7 gph. 6-7 hours flattens both tanks. So in that example, it made a good deal more than rated power, nearly continuously for 7 hours.

Rod

EXACTLY, Rod!

To me the horsepower hours per gallon is the most interesting number as it directly relates the fuel burned to the work done.

But no one else in this thread feels that way, apparently! :wink:

 

[Fritz Maurer]

Thats where lm not making the connection... 113 hp in high range, regardless of gear. Maximum at the drawbar is 116... I am typically in 3 hi or low with the plow 9 inches deep...sixth gear is simply out of the question. And they are claiming 113 hp one-and-a-half notches below road gear? The wheel slippage comment I half get.... Ford says not to over-ballast the tractor to eliminate slippage; some slippage is desirable to preserve the life of the tractor.... but I still dont see how wheel slippage improves fuel economy. Kinda like driving your truck around with the clutch slipping... if the engine races without putting the power to the ground, how does that improve economy?

 

[thehickdaddy]

218 cubic inch continental engine, that was used in the graham paige supercharged cars. The supercharged engine was rated at 116 hp i think, and unsupercharged was only 94 hp. So graham detuned the engine down to 30 hp and shoved it in the tractor.
but the tractor is equipped with the supercharged engine due to several distinctions such as,
1. continental 218 has 2 exhaust valves close together creating a hot spot in the head which graham remedied by means of a special waterpump with an extra port that connects to a external brass pipe that plumbs into the cylinder head between the pair of exhaust valves to promote cooling and prevent burn valves.
2. supercharged engine has wristpin and piston squirters for better cooling during hard use and better start up lubrication
3. supercharged engine has a unique waterpump with safety wire that requires removal before disassembly or the waterpump housing is quickly broken


massey harris tractors and combines used both chrysler and continental engines but as far as i know, Graham Paige cars only used the continentals

at the tractor show last weekend, i was asked the same question. so i removed a side panel to show the engine and asked if they knew the simplest way to tell chrysler from continental flathead sixes? they said no, so i replied to look a distributor. Chrysler distributors come out the block at an angle, but continental engines have distributor vertical out the top of the head. Super simple way to remember how to identify

another difference is that continental flathead sixes only had 1 pair of exhaust valves together where as Chrysler had 2 pairs of exhaust valves together

 

[RodinNS]

Put it this way... HP=Tq X RPM /5252 so hp is just a function of torque and speed. In lower gears you can't tie all of the torque to the ground that you can in higher gears. With higher speed (less gear reduction) there is less torque but obviously higher speed... so you're bringing the torque in line with what the chassis can tie to the ground and the higher speed allows for more power to be harnessed. If you look at the details in the Nebraska tests you'll find a variety of gears and engine speeds.. and generally in lower gears you'll see far less power measured. Whatever gear that forms direct drive in a particular transmission should be most efficient, but due to other variances that may not translate to the test data. For most tests I've looked at on Fords, 6L usually correlates to the highest drawbar power readings. In some of the Ford transmissions 7H is direct, but that depends on the model, etc.

Rod

 

[MarkB_MI]

> The wheel slippage comment I half get.... Ford says not to over-ballast the tractor to eliminate slippage; some slippage is desirable to preserve the life of the tractor.... but I still dont see how wheel slippage improves fuel economy.

Wheel slippage does NOT improve fuel economy, which for tractors is called SPECIFIC fuel consumption and is measured in gallons per horsepower-hour. Yes, slippage reduces ACTUAL fuel consumption, measured in gallons per hour, but it is specific fuel consumption that matters. (The Nebraska test gives specific fuel consumption as horsepower-hours per gallon, which is the reciprocal of gallons per horsepower-hour. Sort of like miles per gallon versus gallons per mile; different ways to express the same information.)

When trying to understand a thermodynamics problem, it's sometimes useful to consider an extreme case. So let's consider the case of ONE HUNDRED PERCENT SLIPPAGE: Put the tractor in neutral and open the throttle all the way. Is the fuel consumption high? Of course not; the engine only has to produce enough power to make up for the parasitic losses in the tractor. So actual fuel consumption is low. But since the tractor is doing no useful work, SPECIFIC fuel consumption (in gallons per hp-hr) is INFINITE.

So what does that tell us about slippage? It tells us that as slippage increases, actual fuel consumption DECREASES but specific fuel consumption INCREASES.

 

[Tx Jim]

IIRC any wheel slippage under 15% is acceptable. It takes more fuel to move a tractor that has ""excess weight to eliminate ALL TIRE SLIPPAGE"". No tire slippage makes tractor pulling plow through tough spots in field more difficult to maintain correct engine rpm's