|Caterpillar D11 - General Characteristics|
|Engineering Role:||Heavy bulldozer|
|Engine model:||CAT C32 ACERT|
|Gross power:||936 hp (698 kW)|
|Flywheel power:||850 hp (634 kW)|
|Operating Weight:||230,581 lb (104,589.8 kg)|
|Width:||10.4 ft (track) 22 ft (blade)|
|Height:||14.9 ft (top of stack)|
|Blade capacity:||57 yd³|
The Caterpillar D11 is a large bulldozer, manufactured by Caterpillar Inc. in East Peoria, Illinois, and mainly used in the mining industry. Primarily designed as a bulldozer, it also used for push-loading scrapers, and ripping rock overburden.
The D11N was introduced in February 1986 to replace the D10. The D11N had some major improvements over the D10, it includes a bigger track and blade, a longer track by 21 inches (0.53 m). The U blade was just under 21 feet (6.4 m) long and 7 feet (2.1 m) high. This increased the blade capacity to 45 cu yd (34 m3). The D11Ns weight was 204,517 pounds (92,767 kg). It was powered by a 770 horsepower (570 kW), 2,105 cubic inch 3508 V-8 Diesel engine. The D11Ns improvements made it over 10 percent more productive than the D10. In 1987 a hydraulically powered impact ripper was added to the D11N which raised the weight up to 225,950 lb (102,490 kg). This would become known as the D11N Impact Ripper.
D11R & D11R Carrydozer
The D11R and D11R Carrydozer were introduced at the Las Vegas, Nevada at MINExpo International 1996. Both were 770 hp (570 kW) and that would be increased to 850 hp (630 kW) later in 1997. Other improvements made to the D11R were Fingertip Controls and Electronic Clutch and Brakes. The Finger Tip Controls (FTC) allowed the D11R to be steered with a single lever (joystick) on the left hand side. The D11R now weighed 230,935 lb (104,750 kg). The Carrydozer version has a special blade with a curvature that allowed 57 yards (52 m) to be pushed. The "Carrydozer" had the structure strengthened considerably for the extra weight and much bigger blade that it carried up front. Both D11Rs received a new Caterpillar 3508B EUI diesel engine with electronic controls at 915 gross hp. The Carrydozer versions weight is just over 120 tons at 248,600 pounds. According to Caterpillar by the year 2000 over 3,000 D11s had been produced at their plant in East Peoria.
D11T & D11T CD
The current D11T was introduced in early 2008 and is also 850 hp (630 kW). This comes as a regular bulldozer and a carrydozer like the previous model. As with the D11R, the D11T Carrydozer can push 57.9 yards (52.9 m) while the regular D11T can push 45 yards (41 m) of earth. A new D11T was on display at the Caterpillar display at Minexpo during the 22 to 24 September 2008 in Las Vegas, Nevada.
The D11T and D11T CD are both powered by the CAT C32 engine with ACERT technology. Another difference between the D11R and the D11T is the controls inside the operator's cabin. Several levers have been changed into electronic switches, and several controls have been moved for increased visibility. Another difference is that the D11T has its exhaust mufflers moved back closer to the front of the cab like the D10T. They stand taller than the ones on the D11N/D11R.
These machines are so big that they have to be broken down for shipment to most sites. Some are shipped in the United States by flat railcars, with just blade, push arms and ripper frame removed. Others are broken down into several units for transport by multiple tractor trailers.
The dozer blade on front of the tractor usually comes in three varieties:
- A Straight Blade ("S-Blade"), which is short and has no lateral curve, no side wings, and can be used for fine grading.
- A Universal Blade ("U-Blade"), which is tall and very curved, and has large side wings to carry more material.
- A Semi Universal ( "S-U" Blade ) combination blade, which is shorter, has less curvature, and smaller side wings.
There is also a special "Coal U-Blade", capable of carrying 74.9 cubic metres (98.0 cu yd). These are only attached to bulldozers that work solely on coal.
D11s are primarily used for moving large quantities of material (dirt, rock, aggregate, etc.) short distances in relatively confined places. For example, they are often used in quarries. The D11 is most commonly found in use in large scale forestry, mining, and quarry operations.
D11s can be adapted for agricultural and rock ripping by fitting a ripper, a long claw-like device on the back of the tractor. Rippers can come singly (single shank) or in groups of two or more (multi shank rippers). Usually, a single shank is preferred for heavy ripping.
Ripping rock allows the ground surface rock to be broken into small, easy to handle and transport rubble which can then be removed so that grading can take place.
Agricultural ripping allows rocky or very hard earth to be broken up so that otherwise unarable land can be put to use in agricultural applications. For example, much of the very best land in the California wine country consists of old lava flows. Ripping shatters the lava, allowing practical agriculture for the wine industry. Hard earth can also be ripped and decompacted to allow the planting of orchards which otherwise could not grow on the land.
The nearest direct competitor to the Caterpillar D11 is the Komatsu D475. The Caterpillar D11 can be distinguished from the Komatsu D475 by the elevated drive sprocket, or "High Drive" system, which results in a triangular, rather than oval, shaped track. The updated version of the Komatsu, the D575A, is the world's largest production bulldozer at 168 tons and 1150 hp. A bigger machine was built by Italian firm ACCO, with twin Caterpillar diesel engines giving a combined power of 1,300 hp (970 kW), and weighing 183 tons, in the 1980s, but this was a special model. 
These images are of a Caterpillar D11R III.
- Benjamin Holt
- Civil engineering
- Heavy equipment
- Komatsu Limited
- "CAT Products - D11T/D11T CD Track-Type Tractor". cat.com. Caterpillar Inc. 2011. Retrieved 2011-01-27.
- Orlemann, Eric C., (2006). - Caterpillar. - St.Paul, Minnesota: MBI. - ISBN 0-7603-2553-7
- Orlemann, Eric C., (2002) - Colossal Caterpilar: The Ultimate Earthmover. - St. Paul, Minnesota: MBI. - ISBN 0-7603-0874-8
- Earthmovers Magazine, October 2008, Page 17, - author Keith Haddock ISSN 1743-0372
- Haddock, Keith, (2000). - Colossal Earthmovers. - Osceola, Wisconsin: MBI. - ISBN 0-7603-0771-7
- Orlemann, Eric C.(2006). Caterpillar. - St. Paul, Minnesota :MBI. ISBN 0-7603-2553-7.