A tank transporter is a combination of a heavy tractor unit or a ballast tractor and a mating full trailer, hydraulic modular trailer or semi-trailer (typically of the "lowboy" type), used for transporting tanks and other armoured fighting vehicles. Some also function as tank recovery vehicles, the tractors of which may be armoured for protection in combat conditions.
Used on roads, tank transporters reduce the wear and tear on tracks and the other components of the powertrains of tracked vehicles. They also conserve fuel, are less damaging of road surfaces, and reduce tank crew fatigue. Overall, they are more efficient at moving tanks at higher speeds and longer distances than the tanks themselves.
Three chassis designs have been used, generally in this order over time as loads became heavier, although there are exceptions.
The lighter tanks of World War I and the interwar period were carried on simple rigid flatbed lorries.
As the weight of tanks became too great for lorry chassis, separate trailers were developed. These carried the entire weight of the tank on their own wheels, putting no weight onto the tractor unit. They are pulled by a ballast tractor connected to a drawbar.
The simplest trailer designs have only two axles, but heavier loads frequently require more than this. Multiple wheels per axle are common, usually four, sometimes a hydraulic modular trailer is employed which can have eight or more axles which are hydraulically steerable and height adjusted.
One advantage of ballast tractors is that they are capable of double heading, where two tractor units are coupled to pull a hydraulic modular trailer.
Other attempts have been made around 1942 with heavy-trucks, as known for the Dart T13 tank tractor.
Some designs, such as the 1928 Aldershot design, [1] grouped pairs of axles at each end of the trailer.
Others, such as the 70-ton cranes trailer used to carry the Second World War-era Tortoise heavy assault tank, had five axles, spaced along the length of the trailer. [2] The end-wheel designs have the advantages of better ability to cross rough ground and steering more easily. Those with axles throughout their length must have suspension that allows the axles to move and also allowing some steering. This makes them more complicated to manufacture. Placing the wheels at the ends also allows the chassis to dip down into a "well", giving a lower centre of gravity during transport. The Cranes trailer had a frame split into two sections of two and three axles, with a carrying bed above them. The outermost four axles had Ackermann steering for their wheels.
The German Sd.Ah.116 trailer of World War II had a steersman's position on the rear bogie.
The ballast tractor for a drawbar trailer must be comparable in weight to its load if it is to have traction, which means that the total weight of the tractor-trailer combination might be as much as twice the useful load. By using a semi-trailer instead, some of the load's weight is instead carried by the tractor. This avoids the need to ballast the tractor, making a greater proportion of the total weight available for the load.
Semi-trailers cannot be moved on their own, or pushed and pulled by ballast tractors. They are only mobile when connected to the correct tractor unit, which can limit their use in recovery.
The simplest semi-trailer is "half of a trailer", having wheels at the rear only and an articulated connection to the tractor unit. A strong metal post or kingpin on the trailer fits into a socket or 'fifth wheel' on the tractor.
Lowboy semi-trailers are commonly used to keep the load's center of mass low, as they have a low horizontal bed, with a gooseneck that rises up at the front to connect to the tractor unit.
As with drawbar trailers, it is simplest if all the axles of a semi-trailer are concentrated at the rear, away from the tractor unit. However, heavier loads may require more axles, and steering gear may be needed at the front of the semi-trailer.
The simplest means of loading the transporter is with a pair of hinged ramps at the rear. The load then drives up the ramps and onto the trailer under its own power. As tracked vehicles exist for their mobility across obstacles, they usually have no difficulty in doing this (however, see the "Power for loading" section below.)
The Cranes trailer described above uses an entire see-saw tilting bed (and two small ramps). A manual hydraulic pump tilts the empty bed, bringing the loading end close to the ground. The tank drives up, then once past the see-saw fulcrum the bed tilts back under its weight.
Some designs use a demountable axle, where the axle detaches from the bed of the trailer. Access to the load bed is now through low ramps, without needing to climb over the height of the wheels. Again, the intention is to keep centre of gravity low.
Although an operational vehicle can be driven on-board under its own power, this is a delicate operation, particularly with tracked vehicles, as their precise steering is limited. In particular, neutral steering, where one track goes forward and one backward causing the tank to turn on the spot, is likely to either damage the trailer bed or to cause the vehicle to fall off.
A few transporters have been fitted with winches for loading, but this is uncommon. [3] More commonly a disabled vehicle is loaded with the assistance of a recovery tractor, either winching or pushing it on board.
Some tank transports are equipped with winches or cranes to also serve as tank recovery vehicles. Some are armoured recovery vehicles. Tanks are usually deployed in groups, with an equal number of transporters to support them. Recovery vehicles are more complex and more expensive and thus only a limited number are produced.
For similar reasons, tank transporters are rarely armoured to recover tanks under fire, although tracked recovery vehicles frequently are. A rare few have been, such as the M26 "Dragon Wagon" of World War II.
Truck model | Origins | Years in use | Users |
---|---|---|---|
Scammell Pioneer semi-trailer as "Scammell 20-ton semi-trailer recovery tank transporter" and "30-ton semi-trailer recovery tank transporter" | UK | 1930s–1940s | British Army, Indian Army |
Mack EXBX 18-ton tank transporter | USA | 1940s | French Army, [i] British Army |
Diamond T tank transporter | USA | 1940s–1970s | British Army, US Army, Dutch Army, Indian Army |
Scammell Commander | UK | 1986–2002 | British Army |
Sd.Kfz. 9/18-ton heavy tank transporter Sd.Ah.116 | Nazi Germany | 1940s | Nazi German Army – Wehrmacht |
Thorneycroft 'Mighty' Antar with 'FV30011 semi-trailer 50-ton tank transporter' | UK | 1940s–1986 | British Army, Dutch Army, Indian Army |
Floor Truck Factory | Netherlands | 1970s–? | Dutch Army |
Faun SLT 50-3 Elefant and SLT-56 | West Germany | 1970s–? | West Germany Army / German Army, Polish Army (since 2002) |
Faun SLT 56 Franziska with Kässbohrer semi-trailer | West Germany | 1989– | West German Army / German Army |
Oshkosh Corporation Commercial Heavy Equipment Transporter (C-HET)- M746 or M911 tractor with M747 semitrailer | USA | 1970s–1990s | US Army |
Oshkosh Corporation Heavy Equipment Transport System | USA | 1993– | US Army, British Army (since 2002) |
Land Mobility Technologies modified Mercedes-Benz Actros Armored Heavy Support Vehicle Systems | Germany / South Africa | 2000s– | Canadian Forces – on order 2007 (delivery 2008–2009) |
DAF Trucks DAF YTZ95.530 (DAF XF) 95 Tropco tractor and trailer | Netherlands | 2005– | Dutch Army, Canadian Forces – loaded from Dutch (2007–2009) |
Type 82 HET – Hanyang Special Auto Works (Hanyang Special Vehicle Works) HY473 tractor and HY962 semi-trailer | People's Republic of China | 1960s | People's Liberation Army |
MAZ-537G tank transporter | Soviet Union | 1960s | Soviet Army, Russian Army, Indian Army, People's Liberation Army, Korean People's Army and various other Eastern Bloc nations |
KZKT-7428 tank transporter | Soviet Union / Russian Federation | 1980s | Soviet Army, Russian Army |
Volvo N1233 | Sweden | 1977– | Swedish Army |
Scania T144 | Sweden | 1998– | Swedish Army, Belgian Army and French Army |
Mitsubishi Fuso Truck and Bus Corporation JGSDF Type 73/74 heavy tank transport | Japan | 1973– | Japan Ground Self-Defense Force |
A semi-trailer truck is the combination of a tractor unit and one or more semi-trailers to carry freight. A semi-trailer attaches to the tractor with a type of hitch called a fifth wheel.
A tractor is an engineering vehicle specifically designed to deliver a high tractive effort at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most commonly, the term is used to describe a farm vehicle that provides the power and traction to mechanize agricultural tasks, especially tillage, and now many more. Agricultural implements may be towed behind or mounted on the tractor, and the tractor may also provide a source of power if the implement is mechanised.
A trailer is an unpowered vehicle towed by a powered vehicle. It is commonly used for the transport of goods and materials.
A dump truck, known also as a dumping truck, dump trailer, dumper trailer, dump lorry or dumper lorry or a dumper for short, is used for transporting materials for construction as well as coal. A typical dump truck is equipped with an open-box bed, which is hinged at the rear and equipped with hydraulic rams to lift the front, allowing the material in the bed to be deposited ("dumped") on the ground behind the truck at the site of delivery. In the UK, Australia, South Africa and India the term applies to off-road construction plants only and the road vehicle is known as a tip lorry, tipper lorry, tipper truck, tip truck, tip trailer or tipper trailer or simply a tipper.
A tow truck is a truck used to move disabled, improperly parked, impounded, or otherwise indisposed motor vehicles. This may involve recovering a vehicle damaged in an accident, returning one to a drivable surface in a mishap or inclement weather, or towing or transporting one via flatbed to a repair shop or other location.
The Mighty Antar was a heavy-duty 6×4 tractor unit built by Thornycroft from the late 1940s onwards. For some decades it was the standard tank transporter of the British Army and was also used by other nations. It was powered by a shortened V8 land version of the V12 Meteor engine, derived from the Merlin and modified to run on diesel, known as the Rolls-Royce Meteorite.
Scammell Lorries Limited was a British manufacturer of trucks, particularly specialist and military off-road vehicles, between 1921 and 1988. From 1955 Scammell was part of Leyland Motors.
A dolly is an unpowered vehicle designed for connection to a tractor unit, truck or prime mover vehicle with strong traction power.
The M19 tank transporter was a heavy tank transporter system used in World War II and into the 1950s. It consisted of a 12-ton 6×4 M20 Diamond T model 980 truck and companion 12-wheel M9 trailer.
A tractor unit, also known as a truck unit, lorry unit, power unit, prime mover, ten-wheeler, semi-tractor, semi-truck, semi-lorry, tractor cab, truck cab, lorry cab, big rig tractor, big rig truck or big rig lorry or simply a tractor, truck, lorry, semi, big rig or rig, is a characteristically heavy-duty towing engine that provides motive power for hauling a towed or trailered load. These fall into two categories: heavy- and medium-duty military and commercial rear-wheel-drive semi-tractors used for hauling semi-trailers, and very heavy-duty typically off-road-capable, often 6×6, military and commercial tractor units, including ballast tractors.
A semi-trailer is a trailer without a front axle. The combination of a semi-trailer and a tractor truck is called a semi-trailer truck.
A heavy hauler is a very large transporter for moving oversize loads too large for road travel without an escort and special permit.
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 feasible, lowboy-style semi-trailers are used to minimize the height of a load's center of mass. Typical drivetrains are 6×4 and 6×6, but 8×6 and 8×8 are also available. Typical ballast tractor loads include oil rig modules, bridge sections, buildings, ship sections, and industrial machinery such as generators and turbines.
A drawbar is a solid coupling between a hauling vehicle and its hauled load. Drawbars are in common use with rail transport; road trailers, both large and small, industrial and recreational; and agricultural equipment.
Eight-wheel drive, often notated as 8WD or 8×8, is a drivetrain configuration that allows all eight wheels of an eight-wheeled vehicle to be drive wheels simultaneously. Unlike four-wheel drive drivetrains, the configuration is largely confined to heavy-duty off-road and military vehicles, such as armored vehicles, tractor units or all-terrain vehicles such as the Argo Avenger.
A lowboy is a semi-trailer with two drops in deck height: one right after the gooseneck and one right before the wheels. This allows the deck to be extremely low compared with other trailers. It offers the ability to carry legal loads up to 12 ft (3.66 m) tall, which other trailers cannot. Lowboys are used to haul heavy equipment such as bulldozers and large industrial equipment.
The SLT 56 is a heavy duty tractor unit and tank transporter currently in use by the German Army.
The Oshkosh M1070 is a U.S. Army tank transporter tractor unit. The primary purpose of this combination for the U.S. Army is the transport of the M1 Abrams tank.
A hydraulic modular trailer (HMT) is a special platform trailer unit which feature swing axles, hydraulic suspension, independently steerable axles, two or more axle rows, compatible to join two or more units longitudinally and laterally and uses power pack unit (PPU) to steer and adjust height. These trailer units are used to transport oversized load, which are difficult to disassemble and are overweight. These trailers are manufactured using high tensile steel, which makes it possible to bear the weight of the load with the help of one or more ballast tractors which push and pull these units via drawbar or gooseneck this combination of tractor and trailer is also termed as heavy hauler.