When the tractor testing program began at the University of Nebraska at Lincoln in 1920, about 160 companies were building tractors in the United States. That first year, 69 machines were tested, a figure that hasn't been matched since. The 1920 tests included such names as Allwork, Coleman, Dart, Emerson-Brantingham, Frick, Gray, Heider, LaCrosse (the only "line-drive" tractor ever tested), Monarch, Parrett, Samson, Square Turn, Townsend, Uncle Sam and Wisconsin, as well as more familiar marques of Case, Fordson, Huber, International and Rumely.
Any manufacturer who wanted a tractor tested at Nebraska had to make application, pay a $500 fee, and wait until the test could be scheduled before shipping the machine to the university. Upon arrival of the equipment, a representative of the manufacturer unloaded the tractor, made sure it was running its best and then operated the machine during the "limber-up" run.
A UNL testing engineer then took charge of the tractor and belted it to a dynamometer. After warm-up, several tests were made, including a 100 percent maximum test, an operating maximum test, a rated load test, and a varying load test, all on the belt. In 1959, with the proliferation of PTO-driven implements and the demise of belt-driven machines, the belt tests were discontinued and a series of three PTO tests was implemented. During all these tests, horsepower output, fuel, oil and water consumption, and operating temperatures were closely monitored and recorded.
After the belt or PTO tests were concluded, the tractor was taken to the test track, which was dirt until 1959, when it was paved with concrete. The tractor was hitched to the test car, hitched behind (if necessary) additional heavy tractors to increase the load. The first test was the 100 percent maximum drawbar test, which was made in the rated (or plow) gear. Next was the operating maximum test, which measured the maximum horsepower the tractor developed in each forward gear. Finally, a 10-hour rated load test was run at 75 percent of the maximum load pulled in the earlier test.
After the tests, each tractor was taken apart to make sure every part matched specifications. Cylinder displacement was checked by removing the head and pouring a measured amount of liquid into the cylinder. This was a simple process on a vertical engine, but consider a different scenario: In a 1941 photo of a John Deere Model B with a horizontal engine, the front has been hoisted into the air until the tractor is standing upright on its drawbar, while technicians pour liquid into its cylinders. A later photo shows a Model B lying on its side, while the liquid is poured through the spark plug hole.
Occasionally, an irregularity was discovered during this process. One episode involved a tractor that was found to have polished intake parts. The tractor was rejected and the company had to submit a second tractor and pay an additional test fee.
During the late 1920s, the Adams test car, with an open top and rubber tires on wooden-spoke wheels, replaced the old Illinois tractor test vehicle. The new car had better test equipment and pulled a ground-driven air compressor to provide a load for small tractors. Larger tractors still required the addition of heavy steam or gas tractors to add to the load. In 1940, the test car was again upgraded with a streamlined, closed cab model that was first used to test the new Ford-Ferguson 9N tractor.
Testing was discontinued at the end of 1941, as no new tractor models were made during the war, and wasn't resumed until late 1946, when an Ellinwood Bear Cat garden tractor (which put out 1.33 drawbar horsepower) was tested. A number of garden tractors were tested over the years, but the smallest was a Choremaster "B" in 1950. The little, single-wheeled machine weighed 123 pounds, put out 0.62 drawbar horsepower and pulled 89 pounds.
On the other hand, some huge tractors were tested at Nebraska. Long-time Test Lab Director Lester Larsen tells of the arrival of an Allis-Chalmers HD-19, the heaviest tractor to date. Normally, the tractor being tested was hitched to the front of the test car and the load was hitched to the rear of the car. Larsen estimated they would need a load consisting of a pair of big Cletrac crawlers, followed by a smaller Cletrac and a Massey-Harris 55, and then a 6-cylinder Oliver and a Case D. He figured such a load might pull the test car in two, so they rigged up a lever arrangement that allowed the HD to pull only a percentage of what it was capable of, and then calculated the maximum pull from that percentage.
In 1963, the old test car cab was mounted on the chassis of an 1800 Oliver tractor, making a much stronger and more sophisticated test vehicle. This configuration was used until 2003, when a new mobile test lab was built by Caterpillar in Peoria, Ill. The new test vehicle can handle today's powerful tractors and is loaded with computerized test equipment to accelerate the testing process.
Through 2001, Nebraska has tested a total of 1,797 tractors, including a Dodge Power Wagon, a Land Rover, a Daimler-Benz Unimog, and a couple of Jeeps. Garden tractors are no longer tested, as the minimum for testing is now 40 hp. The lab tests 10 to 20 tractors per year, with each test taking about a week to complete.
Two bills introduced in the Nebraska Legislature in 2003 would have eliminated the UNL tractor testing program. Proponents of the bills contended that the tractor industry had changed dramatically since 1920, and that today's truth-in-advertising laws would keep manufacturers in line. Tractor manufacturers supported the measure, as lab fees are around $24,000 per tractor and the permit costs $50. In addition, the manufacturer must pay the cost of shipping tractors to UNL and pay a company engineer or two to be on site during the tests. However, as of April 15, 2004, after much lobbying on both sides by interested parties, the proposed legislation is dead for the time being and tractor testing will continue as it has for 85 years.
For more information: The Nebraska Tractor Test Laboratory and the Lester F. Larsen Tractor Test & Power Museum are located on the East Campus of the University of Nebraska at Lincoln.
From I-80 East, take exit 409 (Waverly), turn left on Highway 6 (Cornhusker Highway) and go west about 5 miles to 33rd Street. Turn left and go 4-5 blocks south before turning left on East Campus Loop. Enter the second driveway on the right.
From I-80 West, take exit 403 (North 27th St.). Go south on 27th Street about 2.5 miles and turn left on Cornhusker Highway. Go 6 blocks east to 33rd Street and turn right. Go 4-5 blocks south, turn left on East Campus Loop and enter second driveway on the right.