Tractor pulling

Truck and tractor pulling, also known as power pulling, is a form of a motorsport competition in which antique or modified tractors pull a heavy drag or sled along an , track, with the winner being the tractor that pulls the drag the farthest. The sport is known as the world's most powerful motorsport, due to the multi-engined modified tractor pullers. All tractors in their respective classes pull a set weight in the drag. When a tractor gets to the end of the 100 meter track, this is known as a "full pull". When more than one tractor completes the course, more weight is added to the drag, and those competitors that moved past will compete in a pull-off; the winner is the one who can pull the drag the farthest. The drag is known as a weight transfer drag. This means that, as it is pulled down the track, the weight is transferred (linked with gears to the drag’s wheels) from over the rear axles and towards the front of the drag. In front of the rear wheels, instead of front wheels, there is a "pan". This is essentially a metal plate, and as the weight moves toward it, the resistance between the pan and the ground builds. The farther the tractor pulls the drag, the more difficult it gets.…

Truck and tractor pulling, also known as power pulling, is a form of a motorsport competition in which antique or modified tractors pull a heavy drag or sled along an , track, with the winner being the tractor that pulls the drag the farthest. The sport is known as the world's most powerful motorsport, due to the multi-engined modified tractor pullers. All tractors in their respective classes pull a set weight in the drag. When a tractor gets to the end of the 100 meter track, this is known as a "full pull". When more than one tractor completes the course, more weight is added to the drag, and those competitors that moved past will compete in a pull-off; the winner is the one who can pull the drag the farthest. The drag is known as a weight transfer drag. This means that, as it is pulled down the track, the weight is transferred (linked with gears to the drag’s wheels) from over the rear axles and towards the front of the drag. In front of the rear wheels, instead of front wheels, there is a "pan". This is essentially a metal plate, and as the weight moves toward it, the resistance between the pan and the ground builds. The farther the tractor pulls the drag, the more difficult it gets. Tractor pulling originated from pre-Industrial Era horse pulling competitions in which farmers would compete with one another to see whose teams of draft horses could pull a heavy load over the longest distance. The first known competitions using motorized tractors were held in 1929 in Missouri and Kentucky. Tractor pulling became popular in rural areas across the Midwestern and Southern United States in the 1950s and 1960s. From there it gradually spread to Canada, Europe, and Australia and New Zealand. ==History in the US== Prior to the invention of the tractor, when farm implements were pulled by horses, farmers would boast about the strength of their teams and seek to compare and contest in teams with one another to see who had the most powerful animals. In some cases, they compared horse teams pulling large loads over distance, such as a fully loaded hay cart or wagon. In other situations, a flat board or skid would have a horse or team of horses then hitched to it; weight would be added, usually in the form of rocks, and the driver would urge his horses to pull the load, with more weight added as competitors were eliminated; the animals pulling the most weight or for the greatest distance were judged the strongest. These events became the formalized sport of horse pulling, which is still carried out today with draft horses, specially bred to have high strength for pulling heavy loads. Today, fixed weights on drags are dragged for a set distance and additional weight is added in successive rounds. While it is said that the term horsepower is derived from this event, the concept was developed earlier, in experiments and measurements performed by James Watt and Mason Worrell. It wasn't until 1929 that motorized vehicles were put to use in the first events at Bowling Green, Missouri, and Vaughansville, Ohio. Although the sport was recognized then, it did not really become popular until the '50s and '60s. It was also realized, at that time, there were no uniform set of rules. The rules varied from state to state, county to county, and competitors never knew what standards to follow. This made the sport difficult for new entrants. In 1969, representatives from eight states congregated to create a uniform book of rules to give the sport much-needed structure, and created the National Tractor Pullers Association (NTPA). The NTPA's early years were events that used standard farm vehicles, with the motto "Pull on Sunday, plow on Monday". Pulling remained basically the same through the '70s, with only stock and modified tractors. Stock tractors were commercially available tractors produced by manufacturers, and modified tractors were the basic tractor chassis with another non-tractor engine mounted on it. Tractors remained single-engined until two Ohio brothers, Carl and Paul Bosse, introduced the crossbox, which could allow multiple engines to be attached to a single driveshaft. Other innovators during this period included Bruce Hutcherson, with his triple-Rodeck-engine–powered "Makin Bacon Special", Dave and Ralph Banter and their Chevrolet-powered tractors, and the "Mission Impossible" tractors of Tim Engler, which at one point had up to seven supercharged methanol-fueled engines. Subsequently, modified tractors with four engines were common, while stock tractors tried to catch up by adding multiple large turbochargers, along with intercoolers, but both retained the appearance of a tractor. Soon tractors became single-use machines that were not used on the farm, making the "Pull on Sunday, plow on Monday" motto obsolete. Throughout the '70s and '80s the modified division continued to thrill crowds by adding more engines, and soon the tractors lost their tractor appearance and turned into high 'spec' dragsters. The limit was reached in 1988 when a tractor with seven engines was built. As well as piston engines, turbine engines (frequently mistakenly called "jet engines") appeared in 1974, with Gardner Stone's "General" Tractor, a four-turboshaft unit hitting the hook in 1989. The growing popularity of the sport caused the creation of a new four-wheel–drive division in 1976, which captured a large fan base. The engine sizes in these vehicles continued to increase, from up to and probably would have continued, but in 1989 the NTPA limited displacement to and required natural aspiration, banning supercharging. Today the four-wheel–drive division is one of the most popular with the success of trucks like the Holman Brothers "4-Play" Chevy and Bob Boden's "Studley Studebaker". ===Two-wheel-drive (2WD) truck class=== The two-wheel–drive (2WD) division was introduced in 1983. The division imposes a weight limit of on each competing truck, a maximum width of , and a maximum distance of from the centerline of the rear axle to the front of the vehicle (including weight racks and tow hook). (The length restriction allows for up to of cosmetic fiberglass, however.) Alcohol methane engines with up to eight cylinders are permitted, but diesel engines are not. Any wheelbase is permitted. The National Tractor Pullers Association restricts engines to and two valves per cylinder. They permit tubular steel frames. The maximum tire size for the 2WD class is , with a maximum circumference of when mounted on an rim and inflated to . The ground patch is not to exceed on original tread. ===Super stock, pro-stock, and mini-modified=== Super Stock tractor Open class uses primarily methanol fuel (some are diesel versions). The Super Stock Open machines can generate over and of torque, with billet or re-cast engine blocks. Super Stock Open and Super Stock Diesel tractors may use up to four turbochargers in three stages. The Diesel super stock tractors generate close to and of torque and are allowed to compete in the Open class, which very rarely occurs anymore. However, a true Open (methanol fuel) tractor is not allowed to compete in the Diesel class. There is light Super Stock class which is and the Heavy Super Stock Classes that are . Diesel Pro Stock Tractors are limited to one turbocharger and diesel fuel is the only allowable source for power, in keeping with the 'spirit' of the original tractors. The maximum engine displacement is . These engines can achieve around and of torque. In recent years, new classes have been created to appeal to different groups of pullers. There is now a class called Limited Pro Stock that is limited to engine and turbocharger. This class typically pulls at and is slightly restricted, as opposed to the Pro Stock class, which can run up to engine and an unrestricted size turbocharger, along with intercoolers. The latest addition to Pro Stocks is the Light Pro Stock Class that typically pulls depending on location. These tractors are limited to engines but can run any size turbo. They are not allowed to run intercoolers, however these tractors are making an average of . The light overall weight makes this a driver's class as significant skill is required to keep the tractor on the track. The mini-modified class is a highly specialized and custom built tractor to be fitted with a naturally aspirated engine, at minimum. NTPA Minis are limited to (always an aftermarket V-8 engine block) and uses up to a 14-71 hi helix supercharger. With the driver, they weigh only . Today's engine is capable of a minimum of on methanol or ethanol. Their reputation is known as the wildest ride in pulling, as naturally it is a very high horsepower to weight ratio. Whereas, their larger counterparts, the Modifieds, will weigh , utilizing the same engine that a Mini has, but, with multiple powerplants per custom built tractor chassis. Usually, a maximum of five engines is all that will make the weight limit. Nitromethane and oxidizers were outlawed in 1976. ==History in Australia== ]] The first Australian Tractor Pull was held at the Elmore Field Days (Victoria) in 1976. The following year saw Tractor Pulling begin in the Victorian rural town of Quambatook. It has developed over the years into a highly competitive and technical sport, where the difference between first and last place may be as small as one or two metres. Often the top tractors are separated by mere centimetres. Down Under Modified Tractor Pulling Association (Down Under MTPA) is a non-profit organisation that governs Modified Tractor Pulling in Australia. Their events (Tractor Pulls) are held in conjunction with a promoter, often a community organisation (for example; Apex, Rotary or Lions clubs) or an agricultural show. Down Under MTPA Tractor Pulls are held in locations throughout Australia, predominantly in Victoria, South Australia and New South Wales. In other regions, events are run by independent clubs and associations, including (South East Queensland) SEQ Pullers, (Central Queensland) CQ Pullers, the Western Australian Tractor Pullers Association (WATPA), and Tasmanian Tractor Pullers. Australian Tractor Pulling classes include Open Modified, Super Modified, Limited Modified, Two Wheel Drive, Pro Stock / Open Pro Stock (Smoker), Open / Outlaw Mini Modified, Super Mini Modified, and Mini Modified. Each class is defined by limits on maximum weight, engine modifications, fuel type, and overall physical size. Down Under MTPA also runs Junior Modified Pulling Mowers, a class for competitors aged 8 to 14. These Modified Mowers pull their own smaller version of the sled. ==Drag pulling== In the early days two main techniques were used. Either a dead weight of fixed mass was dragged, or the step-on method was used, where people stood at fixed positions and stepped aboard as the drag passed. Another rule which has now been dropped was that a speed limit should be observed because of injuries resulting from the increased speed at which they boarded. Today's tractors can achieve theoretical speeds over . Today's drags use a complex system of gears to move weights up to . Upon starting, all the weights are over the drag's rear axles, to give an effective weight of the drag plus zero. As the tractor travels the course, the weights are pushed forward off the drag's axles, pushing the front of the drag into the ground, synthetically creating a gain in weight until the tractor is no longer able to overcome the force of friction. Most drags have grouser bars that act like teeth and dig into the soil to stop the sled. ==See also== Tractor-scraper ==Sources== Origins of horse pulling History of tractor/power pulling and sled technology the rules of tractor/power pulling United Pullers of the Carolinas ==External links==

Text derived from https://en.wikipedia.org/w/index.php?oldid=1353644406 under CC BY-SA 4.0; modifications have been made.