The M6 high-speed tractor was an

artillery tractor An artillery tractor, also referred to as a gun tractor, is a specialized heavy-duty form of tractor unit used to tow artillery pieces of varying weights and calibres. It may be wheeled, tracked, or half-tracked. Traction There are two m ...

used by the

US Army The United States Army (USA) is the primary land service branch of the United States Department of Defense. It is designated as the Army of the United States in the United States Constitution.Article II, section 2, clause 1 of the United Stat ...

during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. Manufactured by

Allis-Chalmers Allis-Chalmers was a United States, U.S. manufacturer of machinery for various Industry (economics), industries. Its business lines included list of agricultural machinery, agricultural equipment, heavy equipment, construction equipment, electric ...

, it was used to tow heavy artillery pieces, such as the

8-inch Gun M1 The 8-inch gun M1 was a 203 mm towed heavy gun developed in the United States. At 32,584 m (35,635 yd), it had the longest range of any United States Army, US Army field artillery weapon in World War II. It was also used in small ...

and

240 mm howitzer M1 The 240 mm howitzer M1, popularly nicknamed the "Black Dragon",
, ''T-Patch 36th Infantry Division News ...

. Its G-number was (G-184).

Development

Although in the late 1930s the

lacked a clear mechanization policy, the success of the "

blitzkrieg ''Blitzkrieg'(Lightning/Flash Warfare)'' is a word used to describe a combined arms surprise attack, using a rapid, overwhelming force concentration that may consist of armored and motorized or mechanized infantry formations, together with ...

" in 1939-40 highlighted the need of motorized vehicles for both tactical and strategic maneuver, which meant that

towed artillery Field artillery is a category of mobile artillery used to support armies in the field. These weapons are specialized for mobility, tactical proficiency, short range, long range, and extremely long range target engagement. Until the early 20t ...

would need to move at a speed comparable to that of the

armored fighting vehicles An armoured fighting vehicle (British English) or armored fighting vehicle (American English) (AFV) is an armed combat vehicle protected by armour, generally combining operational mobility with offensive and defensive capabilities. AFVs can b ...

. To achieve this, a series of high-speed tractor was planned, which would tow the different artillery pieces existing (or planned) in the US Army inventory. The "high" speed was considered in comparison with horse-drawn artillery rather than that obtainable with wheeled prime movers or

ballast tractor A ballast tractor is a specially weighted tractor unit of a heavy hauler combination. It is designed to utilize a drawbar to pull or push heavy or exceptionally large trailer loads which are loaded in a hydraulic modular trailer. When feasi ...

s. The models considered in the series included: 7 ton, 13 ton, 18 ton, and 38 ton. Intended to tow heavy artillery pieces such as the

240 mm howitzer M1 The 240 mm howitzer M1, popularly nicknamed the "Black Dragon",
, ''T-Patch 36th Infantry Division News ...

and the

, the M6 tractor was larger and heavier than the M4 tractor, although they had a similar layout. The main differences between both were in the following areas: * Running gear (6 running wheels in the M6, instead of 4 wheels in the M4) * Dimensions * Weight * Towing capacity * Engine It was powered by two six-cylinder, in-line, Waukesha 145GZ

gasoline Gasoline ( North American English) or petrol ( Commonwealth English) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines. When for ...

engines with an

engine displacement Engine displacement is the measure of the cylinder volume swept by all of the pistons of a piston engine, excluding the combustion chambers. It is commonly used as an expression of an engine's size, and by extension as an indicator of the ...

of , each of which gave at 2,100 rev/min. The running gear consisted on six rubber-rimmed wheels per side, with the drive wheel located at the front and a large tensioning wheel at the rear; a layout similar to the one used in the M3 light tank and later in the M4 tractor.

Service history

The M6 tractor was chiefly used in the

European theater The European theatre of World War II was one of the two main Theater (warfare), theatres of combat during World War II, taking place from September 1939 to May 1945. The Allies of World War II, Allied powers (including the United Kingdom, the ...

only in the last months of World War II. Until then large caliber artillery was moved by the

M1 heavy tractor ''M1 heavy tractor'' was a term used by the United States Army during World War II for several different models of "off the shelf" civilian tracked tractors adopted for military use. Under the Ordnance Department, these tractors were meant to t ...

, heavy trucks, or vehicles such as the M33 Prime Mover, M34 Prime Mover or M35 Prime Mover derived from the M3 Medium Tank,

M4 Medium Tank The M4 Sherman, officially medium tank, M4, was the medium tank most widely used by the United States and Western Allies in World War II. The M4 Sherman proved to be reliable, relatively cheap to produce, and available in great numbers. It ...

, and M10 GMC hulls respectively Use of this tractor in the

Pacific theater The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the continen ...

seems to have been limited to training at

Oahu Oahu (, , sometimes written Oahu) is the third-largest and most populated island of the Hawaiian Islands and of the U.S. state of Hawaii. The state capital, Honolulu, is on Oahu's southeast coast. The island of Oahu and the uninhabited Northwe ...

(

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

). Some vehicles were sold to

Israel Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...

after being replaced by

self-propelled artillery Self-propelled artillery (also called locomotive artillery) is artillery equipped with its own propulsion system to move toward its firing position. Within the terminology are the self-propelled gun, self-propelled howitzer, self-propelled mo ...

Users

Surviving vehicles

Overloon War Museum The Overloon War Museum (''Dutch: Oorlogsmuseum Overloon'') in full 'Dutch National War and Resistance Museum Overloon', is a Dutch historical and educational museum located in the North Brabant village of Overloon. It focuses on the history o ...

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

National Military Vehicle Museum, Edinburgh, South Australia

Gallery

File:M6_High_Speed_Tractor_pic3.JPG, M6 tractor, Overloon File: M6 High Speed Tractor pic1.JPG, Side view, M6 tractor, Overloon File:M6 High-Speed Tractor Front.JPG, Front view, M6 Tractor, Overloon File:M6 High Speed Tractor Rear.JPG, Rear view, towing an 8-inch howitzer M1, Overloon

References

Notes

Bibliography

* *

External links

Olive-Drab website, Highspeed M4
''(accessed 2014-03-02)'' {{Allis-Chalmers Allis-Chalmers Manufacturing Company Artillery tractors Military vehicles introduced from 1940 to 1944 World War II military vehicles World War II vehicles of the United States Motor vehicles manufactured in the United States