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Caterpillar D7

Bulldozer

Caterpillar D7

The Caterpillar D7 bulldozer is a workhorse of the US military since World War II

 
 
Caterpillar D7G
Country of origin United States
Entered service 1974
Crew 1 men
Dimensions and weight
Weight 23 t
Length 6.9 m
Width 3.7 m
Height 3.4 m
Performance
Earth working capacity ?
Towed load 35 ~ 40 t
Mobility
Engine Caterpillar 3306T diesel
Engine power 200 hp
Maximum road speed ~ 15 km/h
Range ?

 

   The Caterpillar D7 bulldozer is a commercial design, which first appeared in 1938. This medium bulldozer was adopted by the US military in 1940, during the World War II. With constant upgrades and improvements these machines are used ever since by all service branches of the US military. Currently Caterpillar military products are offered by a subsidiary Caterpillar Defense & Federal Products company. These machines are designed and built in the United States.

   Main role of the Caterpillar D7 bulldozer is earthmoving. It is the primary US military machine for construction of defensive positions and anti-tank ditches. These dozers can be also used for a number of other engineering tasks, such as construction of obstacles, obstacle clearing, route opening, demolition of structures,  and recovery of stuck combat vehicles. During the Vietnam War the D7 dozers were used to clear forests. Once fitted with an armored cab and special mine flail, the D7 can even clear minefields.

   The Caterpillar does not manufacture any special militarized version of this bulldozer. However this versatile earthmoving machine is employed for military applications. Though some modifications are made to commercial D7 dozers prior to military use. These include transport provisions, blackout lights, military paint, keyless ignition and so on.

   This bulldozer is equipped with a detachable blade. Various blades can be fitted. The most common are short and straight blades without side wings and universal blade with side wings, which allows to carry more material. Also there are angle blades, two-way blades and so on. Some D7 dozer are fitted with a rear-mounted rake attachment.

   The D7 dozer can easily tow armored vehicles, that weight up to 35-40 t.

   Some of these dozers were fitted with armored cabs, mounted on vehicle's frame. Such add-on kit requires no modification to the vehicle structure. The armored cab provides protection from small arms fire, artillery shell splinters and mine blasts. Some dozers even have armored engine compartments. Such protection allows to operate in combat or hostile areas. Additional armor reportedly has no effect on the overall earthworking performance.

   The D7 dozer is operated by a single operator. This machine carries no defensive armament. Even versions with armored cabs are normally unarmed.

   This earthmoving machine is powered by a diesel engine. Various models of the D7 have different power outputs. The D7R Series II dozer is powered by a 240 hp engine. The current production model, the D7E, has an electric drive system. Its engine is used to power a pair of electrical motors. Due to its low mobility the D7 bulldozer must be transported on trailer between mission sites.

   In the US military service a couple of Caterpillar D7 bulldozers are typically assigned to combat engineer companies.

   Current models of the D7 dozer are in the middle of the Caterpillar's bulldozer range. The smallest are D3, while the largest are D11 series dozers.

 

Variants

 

   Caterpillar D7 (7M series) is the original model, produced between 1940-1944. Approximately 10 000 units were produced.

   Caterpillar D7A is an armored bulldozer, produced in 1943. Only 138 of these armored bulldozers were built.

   Caterpillar D7 (3T series). It was produced during 1944-1955. Over 28 000 of these bulldozers were produced.

   Caterpillar D7 (4T series). It was produced during 1944-1945.

   Caterpillar D7 (6T series). It was produced in 1945.

   Caterpillar D7C was produced between 1955 and 1959.

   Caterpillar D7D was produced since 1959.

   Caterpillar D7E, manufactured between 1961 and 1967. It was powered by a 160 hp engine.

   Caterpillar D7F was produced between 1969 and 1974. It was powered by a 180 hp engine. It is estimated that more than 15 700 units were produced. In the mid 1990s these crawlers were upgraded in order to extend their service life. Updated version is compatible with the D7G model.

   Caterpillar D7G, produced since 1974. It has a 200 hp engine. There is an armored and remotely-controlled version of this dozer, used for clearing minefields. In 2009 the US Marine Corps replaced it fleet of D7Gs with John Deere's 850J bulldozers, that are known in service as Medium Crawler Tractors (MTCs).

   Caterpillar D7H. It was the first D7 series bulldozer with an elevated drive sprocket. Due to its elevated nature the operator's station provides excellent observation of the blade and rear of the machine.

   Caterpillar D7R was introduced in 1996. It has an elevated sprocket undercarriage, that is more durable and efficient during earthmoving. Operational weight of the dozer is 27 t.

   Caterpillar D7R (Series 2). It is an improved version produced since the mid 2000s. It is the latest model used by the US military. It is powered by a 240 hp engine and weights around 25 t. Armored versions of this dozer are used by Egypt.

   Caterpillar D7E was first introduced in 2008 and replaced in production the previous D7R Series 2 in 2009. It is a current production version, proposed to commercial operators. This machine has electric drive system. The dozer has a 240 hp engine, which powers a pair electric drive motors. Compared to the previous D7R Series II it is 25% more fuel efficient.

 

 
Caterpillar D7

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Caterpillar D7

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Caterpillar D7

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Caterpillar D7

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Caterpillar D7

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Caterpillar D7

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Caterpillar D7

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Caterpillar D7

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Caterpillar D7

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