Tractor pulling

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Race-tractor with 3 V8-engines
Race-tractor with 3 V8-engines
John Deere Pulling Tractor
John Deere Pulling Tractor
Sled
Sled

Tractor pulling, also known as power pulling, is a competition using tractors to pull a heavy sled along a 'track' and is very popular in rural areas. Usually the sled offers progressively greater resistance as it is pulled. It can be a great spectacle, and although the vehicle produces a great deal of noise and smoke and throws dirt everywhere, it doesn't actually travel very far. There are many different classes, from 'factory' tractors to custom built vehicles with multiple engines. There are even one tenth scale radio control (R/C) models that pull scale sleds.

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[edit] History

It is said that around the 1860s when farming machines were pulled by horse, farmers would boast about the strength of their horses. They would claim that their horse could tow large loads, such as a fully loaded hay cart or wagon. Farmers would challenge one another to contests to prove who had the strongest horse. A barn door was removed and laid flat on the ground, the horse was then hitched to it and the farmer ushered the horse to drag the barn door along the ground. One by one, people jumped on the door until the horse could no longer drag it; the horse pulling the most people the greatest distance was judged the strongest. This event, called horse pulling, is still carried out today with specially bred horses trained to have high strength and low stamina. Instead of people, fixed weights on sleds are dragged as far as possible. Whilst it is said that the term horsepower is derived from this event, in reality the term was coined by James Watt.

It wasn't until 1929 that motorized vehicles were put to use in the first events at Bowling Green, Missouri and Vaughansville, Ohio. The sport was recognized then, but didn't really become popular until the 50s and 60s, and it was realised that 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 the needed structure, and created the National Tractor Pullers Association. 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 engine until two Ohio brothers introduced the crossbox which could allow multiple engines to be attached to a single driveshaft. Subsequently, modified tractors with four engines were common, while stock tractors tried to catch up by adding intercooled turbochargers, 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, jet engines appeared in 1974, with a four jet engined unit 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 450 cubic inches/7.3 litres up to 700/11.5 and probably would have continued, but the NTPA limited it to 650/10.6 naturally aspirated and no blown engine in 1989. Blown engines were allowed, but only in the new 1986 division of two-wheel drives or "funny cars" as the NTPA called them.

Three other divisions were created. The super stock, pro-stock and the mini-modified, which is a garden lawn mower mounted with a supercharged V8. Super Stock Open class uses primarily methanol fuel (some are diesel versions). The Super Stock Open machines can generate over 5,000 horsepower. Super Stock tractors may use more than one turbocharger. 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.[1]

[edit] Organizations

There are many different organizations with different rules in tractor pulling. [2] Some include:

  1. PPL - LUCAS OIL Pro Pulling League
  2. MSPA - Mid-South Pullers Association
  3. ESP - Empire State Pullers - New York Circuit Pulling
  4. NTPA - National Tractor Pullers Association
  5. ETPC - European Tractor Pulling Committee
  6. ATPA - Australian Tractor Pullers Association Inc.
  7. BTPA - British Tractor Pullers Association
  8. NTTO - Netherlands Truck- and Tractorpulling Organisation
  9. NR/CTPA - National Radio Control Truck Pulling Association
  10. ABTT - Associação Brasileira de Trekker Trek / Brazilian Tractor Pulling Association
  11. BKTV - Belgian Power Tractor Organisation

[edit] The Sled

In the early days two main techniques were used. Either a dead weight of fixed mass was dragged, or the step-on method, where people stood at fixed positions and stepped aboard as the sled 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 125mph.

Today's sleds use a complex system of gears to move weights up to 65 000 pounds/29 000 kilograms. Upon starting all the weights are over the sled's rear axles, to give an effective weight of the sled plus zero. As the tractor travels the course the weights are pushed forward of the sled's axles, pushing the front of the sled into the ground, synthetically creating a gain in weight until the tractor is no longer able to overcome the force of friction.

[edit] Radio Control (R/C) Pulling

Radio Control truck and tractor pulling has been around since the late 1980s. It was started by a group of people interested in R/C pulling, near Pittsburgh, Pennsylvania, USA. The main R/C pulling group is the NR/CTPA. NR/CTPA also has many, smaller, affiliated clubs, such as County Line R/C Puller's Club, club number one in the NR/CTPA.

[edit] References

  1. ^ http://www.ntpapull.com/Gregg's%20Releases/St.%20Hyacinthe%202006.htm
  2. ^ http://www.google.com/Top/Sports/Motorsports/Tractor_and_Truck_Pulling/Organizations/

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[edit] Sources

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