Caterpillar D9

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Caterpillar D9 - General Characteristics


Engineering Role:	Heavy bulldozer
Propulsion:	Caterpillar tracks
Engine model:	CAT C18 ACERT (D9T) 3408 HEUI (D9R)
Gross power:	346 kW (464 hp) D9T 354 kW (474 hp) D9R
Flywheel power:	306 kW (410 hp) D9T 306 kW (410 hp) D9R 280 kW (375 hp) D9N 343 kW (460 hp) D9L
Operation Weight:	48,784 kg (107,550 lb)
Length:	8.1 m
Width:	4 m (blade)
Height:	4 m
Speed:	11.9 km/h (forward) 14.7 km/h (reverse)
Blade capacity:	13.5 m³ (17.7 yd³) 9 SU blade 16.4 m³(21.4 yd³) 9 U blade

The Caterpillar D9 is a large track-type tractor designed and manufactured by Caterpillar Inc.

Though it comes in many configurations it is usually sold as a bulldozer equipped with a detachable large blade and a rear ripper attachment.

The D9, with 354 kW (474 hp) of gross power and an operating weight of 49 tons, is in the upper end, but not the heaviest, of Caterpillar's track-type tractors, which range in size from the D3 57 kW (77 hp), 8 tons, to the D11 698 kW (935 hp), 104 tons.

The size, durability, reliability, and low operating costs have made the D9 one of the most popular large track-type tractors in the world, with the Komatsu D275A as one of its most direct competitors. The D9 gained media attention in the new millennium due to its use by the Israeli Defense Forces in the destruction of infrastructure as part of its controversial security operations.

1 Engineering and technical description
2 Military applications
3 See also
4 External links

[edit] Engineering and technical description

D9 early model

CAT D9L, the first D9 model to employ the "high drive" configuration.

The D9 is a series of heavy tracked-type tractors, propelled by Caterpillar tracks and usually used as bulldozers. The D9 has undergone several generations of engineering enhancements. Each new generation is denoted with an English letter added to "D9". Until the introducing of the D10 in the 1980's, the D9 was the largest conventional CAT dozer. The D9L was the first variation of the D9 to employ "High-Drive" design in which the driving wheel is located above the track wheels, and not in the same row. The High-Drive gives the "belly pan" more ground clearance. The current versions are the D9R and the D9T models, but older models such as the D9N and D9L are still common. The L, N, R and T models of the D9 are visually very similar, differing primarily in the design of their internal systems. The D9T main difference from the D9R is the installment of the new Cat C18 ACERT engine. The D9L was probably the most powerful D9 in history, with flywheel power of 460 hp.

The D9's primary working tools are the blade, affixed to the front and controlled by 6 hydraulic arms, and the optional ripper, which can be attached to the back. The blade is mainly intended for earthmoving and bulk material handling: pushing up sand, dirt and rubble. It also can be used to push other heavy equipment such as earthmoving scraper pans, and in military applications, main battle tanks. The dozer blade usually comes in 3 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 "S-U" combination blade which is shorter, has less curvature, and smaller side wings. This blade is typically used for pushing piles of large rocks, such as at a quarry.

Like many other bulldozers, the D9 can be fitted with different blades (such as size-9 SU blade and Universal blade) or other devices such as mineplows.

The rear ripper is intended for use in loosening rocky ground and ripping out larger stones. It can also break frozen ground and excavate small ditches. The ripper can be replaced with a multi-shank ripper, allowing the bulldozer to comb the ground.

The size, power and weight of the larger track-type tractors dictate that they are used primarily for major projects. The D9 is most commonly found in use in construction, forestry, mining, waste, and quarry operations.

An IDF Caterpillar D9N bulldozer, nicknamed "דובי" (teddy bear) in Israel.
Its armor allows it to work under heavy fire.

[edit] Military applications

Caterpillar Inc. does not manufacture a military version of the D9 per se, but the attributes that make the D9 popular for major construction projects make it desirable for military applications as well, and in this role - with Israeli modifications and armor - it has been particularly effective for the Israel Defense Forces (IDF) and later for the United States armed forces (the Marine Corps and the US Army) in Iraq.^{[citation needed]}

See also: Armored bulldozer

The Israeli Engineering Corps used armored versions of the D9L, D9N and D9R to combat terrorism from the Palestinian militants. The dozers clear booby-trapped areas, open routes, rescue stuck armored fighting vehicles and build sand mounds.^{[citation needed]} During the Al Aqsa Intifada D9 bulldozers were used to demolish alleged terrorists' houses under fire, as the dozers withstood massive IEDs (some of 200kg and even 500kg of explosives) and even deflected RPG rounds.^{[citation needed]} The armored D9 bulldozers were cited by experts as one of the key factors for the relatively low casualties of the IDF in urban warfare. [1] However, while Israeli saw the operation of bulldozers as a security necessity, it drawn controversy for the great destruction it caused to the Palestinians, especially in Rafah and in Jenin (during Operation Defensive Shield).

On February 7, 2006, the Synod of the Church of England decided to divest itself of approximately USD$2.2 million in Caterpillar Inc. shares, property of the Church of England. This was seen as a move to distance itself from the Israeli army's use of the Caterpillar bulldozers to destroy Palestinian homes and uproot thousands of olive trees during controversial security operations. Additionally, the death of pro-Palestinian and socialist activist Rachel Corrie, who, while acting as a human shield for a house suspected of being an outlet for an arms-smuggling tunnel^{[citation needed]}, was killed under disputed circumstances by a bulldozer operated by the Israeli army, has brought global attention to their use by Israel.

Both military armored D9s and civilian non-armored D9s are being used by Israel's Ministry of Defense in the building of the Israeli West Bank barrier. The main D9 contributions to the project are earthmoving and soil-leveling, clearing a path for the West Bank barrier, and digging trenches in front of the West Bank barrier.

The US army used D9 bulldozers to clear wood in the Vietnam war but after the war it replaced them with smaller and cheaper Caterpillar D7G bulldozers. D7G dozers are still very common in US combat engineering battalions, but there is a resurgent high demand to replace the lighter D7Gs with the newer and more heavily armored D9s.