High-speed dozer from R.G. LeTourneau was forerunner of the skid-steer loader
Long before the era of the modern skid-steer loader, earthmoving pioneer R.G. LeTourneau invented a rubber-tired dozer capable of much higher speeds than the crawler tractor. Known as the Tournadozer, it was steered by slowing or locking the drive wheels on either side, a steering method that became known as the "skid-steer" principle.
But unlike today's skid-steer loaders, the Tournadozer was no compact machine. LeTourneau wanted a machine to push-load his big rubber-tired Tournapull scrapers, which he had introduced in 1938. He felt the slow speed of crawler tractors impeded the productivity of his high-speed earthmovers. He wanted a tractor that would not only be more powerful than anything else on the market, but could also match the speed potential of his motor scrapers.
Beginning in 1943 in typical LeTourneau fashion, he developed a line of four large rubber-tired dozers with engines up to 750 horsepower. Factory wartime orders delayed progress, but after prototype testing, all four models were released into production during 1947.
All the Tournadozers were mechanically propelled, utilized the skid-steer principle for steering, and were fitted with electrically operated blade controls with cable winch. The largest was the huge 750-hp Model A powered by a Packard marine engine running on butane fuel. It carried a 16-foot-wide dozer blade and was capable of a top speed of 14 mph. The Model A was exhibited at the 1948 Chicago Road Show as the largest bulldozer ever built, but then proved unreliable in the field. It never progressed beyond the experimental stage. The 300-hp Model B and 143-hp Model D had limited success, but the Model C and its successor, the Super C, sold by the thousands.
The Model C Tournadozer was originally equipped with a Buda 160-hp diesel engine and "Tournamatic" transmission. It was upgraded to the "Super C" in 1949 with engine choices of either General Motors 6–71 at 186 hp or Cummins HRB-600 at 165 hp. Equipped with a dozer blade measuring 11 feet 4 inches wide, the "Super C" tipped the scales at 34,000 pounds and boasted a top speed of 19 miles per hour. It proved the perfect match for pushing scrapers; cleaning up around large shovels; and performing a multitude of tasks with a range of attachments such as side boom, tree stinger, snow plow, root rake and log skidder. Its high speed enabled it to move quickly from job to job on large construction and mining sites.
R.G. LeTourneau sold his earthmoving equipment line to Westinghouse in 1953, and the Super C Tournadozer continued as a LeTourneau-Westinghouse (Wabco) product. Its power was upped to 218 horsepower, and it survived in the Wabco product line until withdrawn in 1972.
You can read more about the evolution of construction equipment in Keith Haddock's illustrated book "The Earthmover Encyclopedia," available in most bookstores. Also, consider a membership in the Historical Construction Equipment Association, www.hcea.net.