So, the 150 Case is really a fantastic work... The entire machine is of parts that Kory, and all his friends, manufactured, and it's a spectacular thing. Although CASE made some, there aren't any originals still in existance, there's no donors in fencerows, so he had to visit the JI Case archives in Kenosha, and get blueprints.
HOW he manufactured all those things, is just downright cool, check out the video on it:
I don't remember if it was at Forest City, or Mt Pleasant, or Rollag that I met him, I THINK it was Forest City, but he's a super nice guy, and THE ENCYCLOPEDIA of steam traction engines.
For this demonstration, it wasn't a 'tug of war'. As others noted, the physics involved here very clearly favor the Allis, and anyone who's read the Wismer-Luth 1974 paper on predicting agricultural tractive effort will recognize that these machines' designs were not optimized for this type of a scenario, they were designed for two entirely different sets of circumstances, so it's an apples-to-potatos comparison. What they were actually doing here, was showing what the 150 case sounds, looks like, etc., when it's at it's tractive limits.
Yes, having the drawbar higher limits the Case, and the Allis's brute weight and surface contact make it a significantly more powerful piece. The 150 CASE is a single cylinder, double-acting, which means it has the propensity to be 'top' or 'bottom' centered. A twin-cylinder, with crankpins offset 90 degrees (like my little 50hp Flory) will start, and run in either direction, regardless of crank position and load. An engine that will 'top' or 'bottom' center will not be able to develop full operating torque from a standstill, it actually needs to be moving a bit FIRST, and they have no clutch or gears to make that dead-stop pull.
The 150 CASE was designed to pull lots of bottoms, across wheat-land soil, continuously for days on end... and not sink in and get stuck. That means that, although it's BIG, and rather heavy, it's not TOO heavy, and it's got wide enough wheels to prevent sinking into wet spots. Going to narrower wheels would increase surface pressure, thus compaction, and improve tractive effort in cohesive soils, and adding ballast to the wheels would increase it's ability to transfer shaft torque to the ground... but as seen in the pull video, the engine gearing would need to be changed to put those engine revolutions to the wheels. At some point, the limits of tractive effort will be found, but the draft equipment (cable) will need to be horizontal, and the 150 case would need to be ballasted to about same weight as the Allis.
Realize that the 150hp of a steam traction engine isn't about the steam cylinder and crank, or the wheels, or the weight, or the drawbar- it's about the BOILER. A steam engine is never stronger than the firebox area, never stronger than the tubes (fire or water), never stronger than the steam dome... never stronger than the water feeder, the condenser (if it uses one), or the stack. The whole boiler needs to be able to generate enough steam pressure and volume to equate to 150 BOILER horsepower. After that, the steam cylinder(s), mechanisms, etc., all determine wether the BELT will be able to put that boiler to use. After that, the gears, wheels, and machine weight determine what will be put to the ground. IF one were to take the ENGINE, and instead of turning the Case's drive wheels, were to spin a cable capstan at a low enough reduction, it would most certainly pull that Allis, with engine screaming and tracks thrashing, but the capstan would need to be affixed to something serving as a very, very significant anchor point... that's just not the CASE here... (see how I did that?
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So it's not a sham-show, it's just a demonstration. The Allis is simply the best thing they had available to use as an anchor.
Edited by DaveKamp - 24 Sep 2024 at 9:45pm
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