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99-634: Work on the SPG begun in 1933, originally intended to mount the 203 mm howitzer M1931 (B-4) on the T-28 chassis, a quite modern design, as the B-4 had just been recently accepted into service. The prototype was built in July 1934, and the first trials took place in August. Gunnery trials were successful, but mobility trials ended in failure. The use of T-28 components on such a heavy vehicle was

198-409: A drive wheel , or drive sprocket , driven by the motor and engaging with holes in the track links or with pegs on them to drive the track. In military vehicles, the drive wheel is typically mounted well above the contact area on the ground, allowing it to be fixed in position. In agricultural crawlers it is normally incorporated as part of the bogie. Placing suspension on the sprocket is possible, but

297-450: A turret on a tracked chassis so they superficially resemble tanks. However, they are generally lightly armoured, which is insufficient to withstand direct-fire combat; nonetheless this protects their crews against shrapnel and small arms and therefore they are usually included as armoured fighting vehicles . Many are equipped with machine guns for defense against enemy infantry. The key advantage of self-propelled over towed artillery

396-413: A "thrown" track). Jammed tracks may become so tight that the track may need to be broken before a repair is possible, which requires either explosives or special tools. Multi-wheeled vehicles, for example, 8 X 8 military vehicles, may often continue driving even after the loss of one or more non-sequential wheels, depending on the base wheel pattern and drive train. Prolonged use places enormous strain on

495-553: A Lombard log hauler shipped out to a western state by people who would later build the Phoenix log hauler in Eau Claire, Wisconsin, under license from Lombard. The Phoenix Centipeed typically had a fancier wood cab, steering wheel tipped forward at a 45 degree angle and vertical instead of horizontal cylinders . In the meantime, a gasoline-powered motor home was built by Lombard for Holman Harry (Flannery) Linn of Old Town, Maine to pull

594-411: A closed chain. The links are jointed by a hinge, which allows the track to be flexible and wrap around a set of wheels to make an endless loop. The chain links are often broad, and can be made of manganese alloy steel for high strength, hardness, and abrasion resistance. Track construction and assembly is dictated by the application. Military vehicles use a track shoe that is integral to the structure of

693-497: A continuous track, which he called a "universal railway" in 1825. Polish mathematician and inventor Józef Maria Hoene-Wroński designed caterpillar vehicles in the 1830s to compete with the railways. In 1837, Russian army captain Dmitry Andreevich Zagryazhsky (1807 – after 1860) designed a "carriage with mobile tracks" which he patented the same year, but due to a lack of funds and interest from manufacturers he

792-455: A farmers' exhibition in 1896. Steam traction engines were used at the end of the 19th century in the Boer Wars . But neither dreadnaught wheels nor continuous tracks were used, rather "roll-out" wooden plank roads were thrown under the wheels as required. In short, whilst the development of the continuous track engaged the attention of a number of inventors in the 18th and 19th centuries,

891-561: A farmers' exhibition in 1896. According to Scientific American , Charles Dinsmoor of Warren, Pennsylvania invented a "vehicle" on endless tracks, patented as No. 351,749 on November 2, 1886. The article gives a detailed description of the endless tracks. Alvin O. Lombard of Waterville, Maine was issued a patent in 1901 for the Lombard Steam Log Hauler that resembles a regular railroad steam locomotive with sled steerage on front and crawlers in rear for hauling logs in

990-603: A few Komsomolets tractor-mounted 57   mm ZiS-2 guns early in the war. By 1943, the series of Samokhodnaya Ustanovka casemate-armored vehicles had started to appear at the front, starting with the SU-85 , and by late 1944 the SU-100 , which mounted powerful guns on modern chassis adopting the full-casemate enclosure of the crew compartment as the Germans had done with the StuG III. These had

1089-846: A memorandum of 1908, Antarctic explorer Robert Falcon Scott presented his view that man-hauling to the South Pole was impossible and that motor traction was needed. Snow vehicles did not yet exist however, and so his engineer Reginald Skelton developed the idea of a caterpillar track for snow surfaces. These tracked motors were built by the Wolseley Tool and Motor Car Company in Birmingham, tested in Switzerland and Norway, and can be seen in action in Herbert Ponting 's 1911 documentary film of Scott's Antarctic Terra Nova Expedition . Scott died during

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1188-549: A merger of the Holt Manufacturing Company and the C. L. Best Tractor Company , an early successful manufacturer of crawler tractors. With the Caterpillar D10 in 1977, Caterpillar resurrected a design by Holt and Best, the high-sprocket-drive, since known as the " High Drive ", which had the advantage of keeping the main drive shaft away from ground shocks and dirt, and is still used in their larger dozers. In

1287-452: A mistake, and so it was decided to use the components of the more robust T-35. A total of 8 changes were made to the running gear, the same number for the transmission, and 10 changes in equipment all using T-35 components. The same year, a decision was made to build a second prototype, using the T-35 chassis from the start, indexed SU-14-1. The SU-14-1 prototype entered trials in 1936, however,

1386-450: A nine-foot steel v-plow and sixteen foot adjustable leveling wings on either side. Once the highway system became paved, snowplowing could be done by four wheel drive trucks equipped by improving tyre designs, and the Linn became an off highway vehicle, for logging , mining , dam construction, arctic exploration , etc. Modern tracks are built from modular chain links which together compose

1485-597: A patent in 1901 and built the first steam-powered log hauler at the Waterville Iron Works in Waterville, Maine, the same year. In all, 83 Lombard steam log haulers are known to have been built up to 1917, when production switched entirely to internal combustion engine powered machines, ending with a Fairbanks diesel-powered unit in 1934. Alvin Lombard may also have been the first commercial manufacturer of

1584-602: A rear sprocket, the idler wheel is placed higher than the road wheels to allow it to climb over obstacles. Some track arrangements use return rollers to keep the top of the track running straight between the drive sprocket and idler. Others, called slack track , allow the track to droop and run along the tops of large road wheels. This was a feature of the Christie suspension , leading to occasional misidentification of other slack track-equipped vehicles. Continuous track vehicles steer by applying more or less drive torque to one side of

1683-582: A score of engines fitted with dreadnaught wheels. In April 1858, the journal The Engineer gave a brief description of a Clayton & Shuttleworth engine fitted with dreadnaught wheels, which was supplied not to the Western Allies, but to the Russian government for heavy artillery haulage in Crimea in the post-war period. Steam tractors fitted with dreadnaught wheels had a number of shortcomings and, notwithstanding

1782-500: A significant role throughout the Cold War era conflicts and in the 1991 Gulf War . Modern SP artillery is highly computerized, with the ability to self-survey firing positions using systems such as GPS and inertial navigation systems . This, in conjunction with digital fire control /ballistic computers and digital communications, allows individual guns to disperse over a wide area and still deliver rounds on target simultaneously with

1881-530: A simple rocket rack on the back, a cheap and crushingly effective weapon, provided area saturation was called for rather than accurate fire. The Axis powers had captured the Katyusha and made their own versions; Germany created the 8 cm Raketen-Vielfachwerfer , while Romania developed the Mareșal tank destroyer , an early prototype of which was armed with a Katyusha. It also had self-propelled howitzer versions. After

1980-520: A single bogie that includes the idler-wheel and sometimes the sprocket. Many World War II German military vehicles, initially (starting in the late 1930s) including all vehicles originally designed to be half-tracks and all later tank designs (after the Panzer IV ), had slack-track systems, usually driven by a front-located drive sprocket, the track returning along the tops of a design of overlapping and sometimes interleaved large diameter road wheels, as on

2079-437: A small number of relatively long 'longitudinal' treads. Further to Fowler's patent of 1858, in 1877, a Russian, Fyodor Blinov , created a tracked vehicle called " wagon moved on endless rails". It lacked self-propulsion and was pulled by horses. Blinov received a patent for his "wagon" in 1878. From 1881 to 1888 he developed a steam-powered caterpillar-tractor. This self-propelled crawler was successfully tested and featured at

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2178-457: A smaller jockey/drive wheel between each pair of wheels, to support the 'track'. Comprising only eight sections, the 'track' sections are essentially 'longitudinal', as in Boydell's initial design. Fowler's arrangement is a precursor to the multi-section caterpillar track in which a relatively large number of short 'transverse' treads are used, as proposed by Sir George Caley in 1825, rather than

2277-513: A system of vehicle propulsion used in tracked vehicles , running on a continuous band of treads or track plates driven by two or more wheels. The large surface area of the tracks distributes the weight of the vehicle better than steel or rubber tyres on an equivalent vehicle, enabling continuous tracked vehicles to traverse soft ground with less likelihood of becoming stuck due to sinking. Modern continuous tracks can be made with soft belts of synthetic rubber , reinforced with steel wires, in

2376-402: A track laying mechanism, although these designs do not generally resemble modern tracked vehicles. In 1877 Russian inventor Fyodor Abramovich Blinov created a horse-drawn tracked vehicle called " wagon moved on endless rails", which received a patent the next year. In 1881–1888 he created a steam-powered caterpillar-tractor. This self-propelled crawler was successfully tested and showed at

2475-402: A vehicle's cross-country traction, in theory they prevent damage to any pavement. Additionally, the loss of a single segment in a track immobilizes the entire vehicle, which can be a disadvantage in situations where high reliability is important. Tracks can also ride off their guide wheels, idlers or sprockets, which can cause them to jam or to come completely off the guide system (this is called

2574-588: A vehicle's cross-country traction, they prevent damage to any pavement. Some pad systems are designed to remove easily for cross-country military combat . Starting from late 1980s, many manufacturers provide rubber tracks instead of steel, especially for agricultural applications. Rather than a track made of linked steel plates, a reinforced rubber belt with chevron treads is used. In comparison to steel tracks, rubber tracks are lighter, waste less power on internal friction, make less noise and do not damage paved roads. However, they impose more ground pressure below

2673-479: 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 mortar , and self-propelled rocket artillery . They are high-mobility vehicles, usually based on continuous tracks carrying either a large field gun , howitzer , mortar , or some form of rocket / missile launcher. They are usually used for long-range indirect bombardment support on

2772-400: Is a 120 mm automatic twin-barrelled, breech-loaded mortar turret. There are also numerous AFVs and even main battle tanks that can be equipped with a mortar, either outside or inside the cabin. The Israeli Merkava main battle tank carried a 60 mm mortar in the small troop compartment in the rear, which fired through an opening in the roof, allowing the crew to remain protected. This

2871-405: Is mechanically more complicated. A non-powered wheel, an idler , is placed at the opposite end of the track, primarily to tension the track, since loose track could be easily thrown (slipped) off the wheels. To prevent throwing, the inner surface of the track links usually have vertical guide horns engaging grooves, or gaps between the doubled road and idler/sprocket wheels. In military vehicles with

2970-457: Is retained by his surviving family. Frank Beamond (1870–1941), a less-commonly known but significant British inventor, designed and built caterpillar tracks, and was granted patents for them in a number of countries, in 1900 and 1907. A first effective continuous track was not only invented but really implemented by Alvin Orlando Lombard for the Lombard Steam Log Hauler . He was granted

3069-537: Is slightly more complex, with each link connected to the next by a bushing which causes the track to bend slightly inward. A length of live track left on the ground will curl upward slightly at each end. Although the drive sprocket must still pull the track around the wheels, the track itself tends to bend inward, slightly assisting the sprocket and somewhat conforming to the wheels. Tracks are often equipped with rubber pads to improve travel on paved surfaces more quickly, smoothly and quietly. While these pads slightly reduce

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3168-414: Is that it can be brought into action much faster. Before the towed artillery can be used, it has to stop, unlimber and set up the guns. To move position, the guns must be limbered up again and brought—usually towed—to the new location. By comparison, self-propelled artillery can stop at a chosen location and begin firing almost immediately, then quickly move on to a new position. This shoot-and-scoot ability

3267-555: Is very useful in a mobile conflict and particularly on the advance in open battlefields. Conversely, towed artillery was and remains cheaper to build and maintain. It is also lighter and can be deployed in areas that self-propelled guns cannot reach. Since the Vietnam War , heavy transport helicopters have also been used for rapid artillery deployment albeit at considerable expense and risk, mitigating one of towed artillery's disadvantages. Both self-propelled and towed artillery remain in

3366-503: The British Army on several occasions between 1905 and 1910, but not adopted. The Hornsby tractors pioneered a track-steer clutch arrangement, which is the basis of the modern crawler operation. The patent was purchased by Holt. The name Caterpillar came from a soldier during the tests on the Hornsby crawler, "trials began at Aldershot in July 1907. The soldiers immediately christened

3465-710: The Brummbär ), leftover chassis from cancelled programs ( Elefant and Sturer Emil ); others were converted from battle-damaged tanks ( Sturmtiger ). The single most-produced armored fighting vehicle design for Germany in WW II, the Sturmgeschütz III (StuG III) assault gun, in 1936–1937 pioneered the later casemate-style fully enclosed armor that would be used on almost all late-war German self-propelled artillery and Jagdpanzer -format tank destroyers. The Soviets experimented with truck- and tank-based self-propelled weapons, producing

3564-614: The Crimean War , waged between October 1853 and February 1856, the Royal Arsenal at Woolwich manufacturing dreadnaught wheels. A letter of recommendation was signed by Sir William Codrington, the General commanding the troops at Sebastopol. Boydell patented improvements to his wheel in 1854 (No. 431) – the year his dreadnaught wheel was first applied to a steam engine – and 1858 (No. 356), the latter an impracticable palliative measure involving

3663-504: The Islamic gunpowder empires , especially those of Iran, especially in the rugged Iranian plateau , where the transportation of heavy cannons is difficult. The British Gun Carrier Mark I was the first example of a self-propelled gun, fielded in 1917 during World War I . It was based on the first tank , the British Mark I and carried a heavy field gun. The gun could either be fired from

3762-533: The M3 half track and M113 APC , to vehicles specifically intended to carry a mortar, such as the 2S31 Vena . The Israeli Makmat is a mortar carrier based on the M4 Sherman tank chassis. The Russian army uses a 2S4 Tyulpan (Tulip) self-propelled 240 mm heavy mortar. Patria Hägglunds , a joint venture between Finnish Patria and Swedish BAE Systems Hägglunds , manufactures AMOS (Advanced Mortar System), which

3861-788: The Marder I , using captured French Lorraine 37L tractors, the Marder II , using the Panzer II light tank chassis, and the Marder III , which was based on the Panzer 38(t) Czech chassis. These led to better-protected assault guns – Sturmgeschütz – with fully enclosed casemates , built on medium tank chassis. In the same way self-propelled anti-tank guns such as the Jagdpanzer IV and Jagdpanther were built. Some designs were based on existing chassis (such as

3960-548: The arsenals of many modern armies. During the Thirty Years' War , early 17th-century experiments were made with early types of horse artillery . Batteries towed light field guns where most or all of the crew rode horses into battle. The gunners were trained to quickly dismount, deploy the guns and provide instant fire support to cavalry, and act as a flexible reserve. The Russian army organized small units of horse artillery that were distributed among their cavalry formations in

4059-448: The 152mm naval gun (B-30) so there was no need to change it. As a result, factory #185 received only one Br-2 gun. Since the SU-14 and SU-14-1 chassis were somewhat different, the conversions were also different. Nevertheless, the overall concept was the same, the vehicles would fire directly from a range of 1500-2000 m, the front armor was increased to 50 mm, the sides were 30 mm thick (60 mm in

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4158-496: The 70bhp No.2 machine the 'caterpillar'." Holt adopted that name for his "crawler" tractors. Holt began moving from steam to gasoline-powered designs, and in 1908 brought out the 40-horsepower (30 kW) "Holt Model 40 Caterpillar". Holt incorporated the Holt Caterpillar Company, in early 1910, later that year trademarked the name "Caterpillar" for his continuous tracks. Caterpillar Tractor Company began in 1925 from

4257-714: The British Sexton (25 pdr) and the German Wespe and Hummel being typical examples. A different route was chosen by the Soviets, who did not develop a specialized indirect-fire vehicle, but following a tradition of dual-purpose towed artillery, built a series of versatile assault guns with indirect-fire capabilities (example ISU-152 ). A related and novel program was the development of the Soviet Katyusha self-propelled multiple rocket launchers , which were unarmored trucks with

4356-701: The Lord Mayor's show in London, and in the following month that engine was shipped to Australia. A steam tractor employing dreadnaught wheels was built at Bach's Birmingham works, and was used between 1856 and 1858 for ploughing in Thetford; and the first generation of Burrell/Boydell engines was built at the St. Nicholas works in 1856, again, after the close of the Crimean War. Between late 1856 and 1862 Burrell manufactured not less than

4455-767: The Northeastern United States and Canada. The haulers allowed pulp to be taken to rivers in the winter. Prior to then, horses could be used only until snow depths made hauling impossible. Lombard began commercial production which lasted until around 1917 when focus switched entirely to gasoline powered machines. A gasoline-powered hauler is on display at the Maine State Museum in Augusta, Maine . After Lombard began operations, Hornsby in England manufactured at least two full length "track steer" machines, and their patent

4554-565: The SU-14 in 1937. However, the SU-14 was only formally cancelled in August 1938. Both SU-14s remained at the Artillery Directorate's Scientific Research Artillery Proving Grounds. In 1940, the Committee of Defense ordered factory #185 to equip the two SU-14s with full armor and the 152 mm M1935 (Br-2) gun, serving as bunker busters in Finland. The requirements changed, as the SU-14 already had

4653-484: The StuG III, and the immense 152 mm howitzer-armed, Soviet ISU-152 , both fully casemated in their design, are examples of this type of self-propelled artillery. All major nations developed self-propelled artillery that would be able to provide indirect support while keeping pace with advancing armoured formations. These were usually lightly armoured vehicles with an open-topped hull; the American M7 Priest ,

4752-507: The War. This mounted an 18-pounder field gun, capable of both the usual artillery trajectories and high-angle anti-aircraft fire , on a Vickers medium tank chassis. It was designed and built for investigations into a general approach to warfare where all arms, infantry and artillery included, would be able to operate over the same terrain as tanks. The Red Army also experimented with truck- and tank-mounted artillery, but produced none in quantity. At

4851-511: The advantage of being relatively cheap to build and mounting a larger gun compared to the conventional tank that they were derived from, but at the expense of flexibility. Heavily armoured assault guns were designed to provide direct-fire support to infantry in the face of enemy defenses. Although often similar to tank destroyers, they carried larger-caliber guns with weaker anti-armor performance but capable of firing powerful HE projectiles. The German 105 mm howitzer-armed StuH 42 based on

4950-590: The battlefield. In the past, self-propelled artillery has included direct-fire vehicles, such as assault guns and tank destroyers , which were typically well-armoured vehicles often based upon the chassis of a tank . In lieu of the standard tank's general-purpose main gun that fired both high-explosive and anti-tank ammunition, direct-fire vehicles had specialized roles, with assault guns providing close fire-support for infantry and tank destroyers mounting an anti-tank gun to take on enemy armour. Modern self-propelled artillery vehicles often mount their main gun in

5049-451: The case of lighter agricultural machinery . The more common classical type is a solid chain track made of steel plates (with or without rubber pads), also called caterpillar tread or tank tread , which is preferred for robust and heavy construction vehicles and military vehicles . The prominent treads of the metal plates are both hard-wearing and damage resistant, especially in comparison to rubber tyres. The aggressive treads of

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5148-433: The chain in order to reduce track weight. Reduced weight allows the vehicle to move faster and decreases overall vehicle weight to ease transportation. Since track weight is completely unsprung , reducing it improves suspension performance at speeds where the track's momentum is significant. In contrast, agricultural and construction vehicles opt for a track with shoes that attach to the chain with bolts and do not form part of

5247-530: The chain's structure. This allows track shoes to break without compromising the ability of the vehicle to move and decrease productivity but increases the overall weight of the track and vehicle. The vehicle's weight is transferred to the bottom length of track by a number of road wheels, or sets of wheels called bogies . While tracked construction equipment typically lacks suspension due to the vehicle only moving at low speeds, in military vehicles road wheels are typically mounted on some form of suspension to cushion

5346-420: The creations of the late 1850s, were never used extensively. In August 1858, more than two years after the end of the Crimean War , John Fowler filed British Patent No. 1948 on another form of "Endless Railway". In his illustration of the invention, Fowler used a pair of wheels of equal diameter on each side of his vehicle, around which pair of toothed wheels ran a 'track' of eight jointed segments, with

5445-567: The damage that their all-steel versions cause to the surface on which they pass: They often cause damage to less firm terrain such as lawns, gravel roads, and farm fields, as the sharp edges of the track easily rout the turf. Accordingly, vehicle laws and local ordinances often require rubberised tracks or track pads. A compromise between all-steel and all-rubber tracks exists: attaching rubber pads to individual track links ensures that continuous track vehicles can travel more smoothly, quickly, and quietly on paved surfaces. While these pads slightly reduce

5544-523: The development of tanks in several countries. The first tanks to go into action, the Mark I , built by Great Britain, were designed from scratch and were inspired by, but not directly based on, the Holt. The slightly later French and German tanks were built on modified Holt running gear. A long line of patents disputes who was the "originator" of continuous tracks. There were a number of designs that attempted to achieve

5643-769: The drive transmission and the mechanics of the tracks, which must be overhauled or replaced regularly. It is common to see tracked vehicles such as bulldozers or tanks transported long distances by a wheeled carrier such as a tank transporter or train , though technological advances have made this practice less common among tracked military vehicles than it once was . The pioneer manufacturers have been replaced mostly by large tractor companies such as AGCO , Liebherr Group , John Deere , Yanmar , New Holland , Kubota , Case , Caterpillar Inc. , CLAAS . Also, there are some crawler tractor companies specialising in niche markets. Examples are Otter Mfg. Co. and Struck Corporation., with many wheeled vehicle conversion kits available from

5742-434: The earlier TOT ( time on target ) concept. The necessary rapid reloading is made possible by an automated ammunition feed system. Rockets have greater ranges and carry much more complex " shells " than guns, since there is less restriction on size (calibre). A multiple launch rocket system (MLRS) can be used to saturate a large area with sub-munitions. Continuous track Continuous track or tracked treads are

5841-649: The early 18th century. While not forming large batteries and employing only lighter 2- and 3-pound guns, they were still effective and inflicted serious losses to Prussian units in the Seven Years' War . This inspired Frederick the Great to organize the first regular horse artillery unit in 1759. Other nations quickly realized the capability of the new arm and by the start of French Revolutionary Wars in 1790s Austria, Hannover, Portugal, Russia, France, Great Britain and Sweden had all formed regular units of horse artillery. The arm

5940-678: The end of World War II , the assault gun fell from use with a general trend towards a single heavy gun-equipped vehicle, the main battle tank , although some wheeled AFVs such as the South African Rooikat , the Maneuver Combat Vehicle of the JGSDF , and the US M1128 MGS , among others, are still developed with large-caliber, direct-fire weapons. Self-propelled indirect-fire artillery remains important and continues to develop alongside

6039-462: The equipment wagon of his dog & pony show, resembling a trolley car only with wheels in front and Lombard crawlers in rear. Linn had experimented with gasoline and steam-powered vehicles and six-wheel drive before this, and at some point entered Lombard's employment as a demonstrator, mechanic and sales agent. This resulted in a question of proprietorship of patent rights after a single rear-tracked gasoline-powered road engine of tricycle arrangement

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6138-592: The expedition in 1912, but expedition member and biographer Apsley Cherry-Garrard credited Scott's "motors" with the inspiration for the British World War I tanks, writing: "Scott never knew their true possibilities; for they were the direct ancestors of the 'tanks' in France." In time, however, a wide array of vehicles were developed for snow and ice, including ski slope grooming machines , snowmobiles , and countless commercial and military vehicles. Continuous track

6237-417: The front section), and the rear was 20 mm thick. There were also several changes for the fighting compartment, which was rearranged, making room for 28 rounds of ammunition, a TK-3 radio set and TPU-2 intercom, while providing ample room for the 6-man crew operating the guns. For defense, 4 DT machine guns were carried inside the vehicles with 5 mounts for them, and one P-40 AA mount on the roof. Due to delays in

6336-480: The general use and exploitation of the continuous track belonged to the 20th century, mainly in the United States and England . A little-known American inventor, Henry Thomas Stith (1839–1916), had developed a continuous track prototype which was, in multiple forms, patented in 1873, 1880, and 1900. The last was for the application of the track to a prototype off-road bicycle built for his son. The 1900 prototype

6435-509: The general-purpose field gun. Many vehicles have used ancillary smoke mortars for local defense, which project one or more smoke grenades in a pattern that allows them to lay down a smoke screen some distance in order to conceal the vehicle from enemy observers. Mortar carriers are vehicles which carry a mortar as a primary weapon. Numerous vehicles have been used to mount mortars, from improvised civilian trucks used by insurgents , to modified infantry fighting vehicles , such as variants of

6534-408: The gun and its crew. Many of the early designs were improvised, and the lessons learned led to better designs later in the war. For example, the first British design, " Bishop ", carried the 25 pdr gun-howitzer on a Valentine tank chassis, but in a mounting that severely limited the gun's performance. It was replaced by the more effective Sexton . The first battery of self-propelled artillery guns

6633-521: The increased firepower provided by modern mobile howitzers is the latest version of the 155 mm G6 howitzer , the G6-52. It can fire up to six rounds in quick succession that will land nearly simultaneously. This is achieved by firing the shells at different trajectories so that the first round has the longest flight time and the last round the shortest. This is an improvement of the concept of multiple-round simultaneous impact (MRSI), itself an enhancement of

6732-427: The lifting one or other of the driving wheels to facilitate turning. A number of manufacturers including Richard Bach, Richard Garrett & Sons , Charles Burrell & Sons and Clayton & Shuttleworth applied the Boydell patent under licence. The British military were interested in Boydell's invention from an early date. One of the objectives was to transport Mallet's Mortar , a giant 36 inch weapon which

6831-438: The load over the track. The choice of overlapping/interleaved road wheels allowed the use of slightly more transverse-orientation torsion bar suspension members, allowing any German tracked military vehicle with such a setup to have a noticeably smoother ride over challenging terrain, leading to reduced wear, ensuring greater traction and more accurate fire. However, on the Russian front, mud and snow would become lodged between

6930-525: The other guns in their battery. These capabilities also increase survivability manyfold as modern SP artillery can displace and avoid counterbattery fire much more quickly and effectively and, if desired, more frequently than previously possible. In conjunction with modern logistic systems (where the SP gun's systems can track and report on ammunition consumption and levels) with similar navigation systems and palletized load dropping / lifting capabilities mean that

7029-545: The outbreak of World War II, virtually all artillery was still being moved around by artillery tractors or horses. While the German Blitzkrieg doctrine called for combined-arms action, which required fire support for armoured units, during the invasion of Poland and France this was provided by the Luftwaffe using Junkers Ju 87 'Stuka' dive-bombers effectively acting as artillery. Conventional towed howitzers followed. As

7128-485: The overlapping wheels, freeze, and immobilize the vehicle. As a tracked vehicle moves, the load of each wheel moves over the track, pushing down and forward that part of the earth or snow underneath it, similarly to a wheeled vehicle but to a lesser extent because the tread helps distribute the load. On some surfaces, this can consume enough energy to slow the vehicle down significantly. Overlapped and interleaved wheels improve performance (including fuel consumption) by loading

7227-422: The production between 1917 and 1952, approximately 2500 units, was sold directly to highway departments and contractors. Steel tracks and payload capacity allowed these machines to work in terrain that would typically cause the poorer quality rubber tyres that existed before the mid-1930s to spin uselessly, or shred completely. Linn was a pioneer in snow removal before the practice was embraced in rural areas, with

7326-452: The rapid displacement can occur without significant disruption to actually firing missions as it is possible for the ammunition to keep up with the guns. A modern battery of six guns, each firing 43 kg projectiles with a burst firing speed of four rounds per minute, can deliver over a tonne of ordnance per minute for up to four minutes. This is an immense weight of fire , which can be delivered with very high accuracy. One example of

7425-568: The ride over rough ground. Suspension design in military vehicles is a major area of development; the very early designs were often completely unsprung. Later-developed road wheel suspension offered only a few inches of travel using springs, whereas modern hydro-pneumatic systems allow several feet of travel and include shock absorbers . Torsion-bar suspension has become the most common type of military vehicle suspension. Construction vehicles have smaller road wheels that are designed primarily to prevent track derailment and they are normally contained in

7524-488: The right to produce vehicles under his patent. At about the same time a British agricultural company, Hornsby in Grantham , developed a continuous track which was patented in 1905. The design differed from modern tracks in that it flexed in only one direction, with the effect that the links locked together to form a solid rail on which the road wheels ran. Hornsby's tracked vehicles were given trials as artillery tractors by

7623-553: The same year. However, in the Red Army's Artillery Directorate wrote in 1936 that the SU-14-1 could not be accepted for military trials, let alone mass production, one of the reasons being the slow rate of fire of only one shot per 5-7 minutes due to issues with the gun. Furthermore, Chief Designer P. N. Siachyntov was arrested on December 31, 1936, due to most of his projects being rejected for mass-production, thus halting further development of

7722-567: The supply of the armor plates to factory #185, both would arrive too late to serve in the Winter War . With the start of Operation Barbarossa , as the German forces approached Moscow and the Kubinka proving grounds, the two SU-14 and T-100Y prototypes were shipped to Kazan in the fall of 1941, where they served as specimens in technical courses, returning to Kubinka in 1943. The first prototype, as SU-14,

7821-474: The suspension systems of the Tiger I and Panther tanks, generically known by the term Schachtellaufwerk (interleaved or overlapping running gear) in German, for both half-track and fully tracked vehicles. There were suspensions with single or sometimes doubled wheels per axle, alternately supporting the inner and outer side of the track, and interleaved suspensions with two or three road wheels per axle, distributing

7920-420: The track more evenly. It also must have extended the life of the tracks and possibly of the wheels. The wheels also better protect the vehicle from enemy fire, and mobility is improved when some wheels are missing. This relatively complicated approach has not been used since World War II ended. This may be related more to maintenance than to original cost. The torsion bars and bearings may stay dry and clean, but

8019-456: The tracks provide good traction in soft surfaces but can damage paved surfaces, so some metal tracks can have rubber pads installed for use on paved surfaces. Other than soft rubber belts, most chain tracks apply a stiff mechanism to distribute the load equally over the entire space between the wheels for minimal deformation, so that even the heaviest vehicles can move easily, just like a train on its straight tracks. The stiff mechanism

8118-517: The tractor crawler. At least one of Lombard's steam-powered machines apparently remains in working order. A gasoline-powered Lombard hauler is on display at the Maine State Museum in Augusta. In addition, there may have been up to twice as many Phoenix Centipeed versions of the steam log hauler built under license from Lombard, with vertical instead of horizontal cylinders. In 1903, the founder of Holt Manufacturing, Benjamin Holt , paid Lombard $ 60,000 for

8217-410: The vehicle than the other, and this can be implemented in a variety of ways. Tracks may be broadly categorized as live or dead track. Dead track is a simple design in which each track plate is connected to the rest with hinge-type pins. These dead tracks will lie flat if placed on the ground; the drive sprocket pulls the track around the wheels with no assistance from the track itself. Live track

8316-568: The vehicle was accepted into service in June 1935, a decision on the result of the trials of the modified SU-14. Trials for the SU-14-1 proved to have unexpected results: a total of 167 various defects were discovered. While the engineer team was ordered to fix the issues of the SU-14-1, a decision was made to install a superior weapon, the 152 mm naval gun B-30 on the original SU-14. This gun was installed in 1937 and gunnery trials were conducted in September of

8415-568: The vehicle, or removed and set up as normal. In effect, the carrier replaced the use of a separate horse team or internal combustion engine-powered artillery tractor , and allowed a new way for the gun to be used. The next major advance can be seen in the Birch gun developed by the British for their motorised warfare experimental brigade (the Experimental Mechanized Force ) after the end of

8514-486: The war progressed, most nations developed self-propelled artillery. Some early attempts were often no more than a field gun or anti-tank gun mounted on a truck—a technique known in the British Army as carrying portee . These were mobile, but lacked protection for the crew. The next step was to mount the guns on a tracked chassis (often that of an obsolete or superseded tank) and provide an armoured superstructure to protect

8613-413: The wheels and tread work in mud, sand, rocks, snow, and other surfaces. In addition, the outer wheels (up to nine of them, some double) had to be removed to access the inner ones. In WWII, vehicles typically had to be maintained for a few months before being destroyed or captured , but in peacetime, vehicles must train several crews over a period of decades. Transfer of power to the track is accomplished by

8712-533: The wheels, as they are not able to equalize pressure as well as the stiff mechanism of track plates, especially the spring loaded live tracks. Another disadvantage is that they are not disassemblable into tracks and therefore cannot be repaired, having to be discarded as whole if once damaged. Previous belt-like systems, such as those used for half-tracks in World War II, were not as strong, and during military actions were easily damaged. The first rubber track

8811-481: Was built to replace the larger motor home in 1909 on account of problems with the old picturesque wooden bridges. This dispute resulted in Linn departing Maine and relocating to Morris, New York, to build an improved, contour following flexible lag tread or crawler with independent suspension of halftrack type, gasoline and later diesel powered. Although several were delivered for military use between 1917 and 1946, Linn never received any large military orders. Most of

8910-544: Was created when Hauptmann Alfred Becker , a mechanical engineer and battery captain in the 227th Infantry Division , mounted his 10.5 cm leFH 16 howitzers on the chassis of captured British Vickers Mk.VI light tanks to mobilize his guns. His 10.5 cm leFH 16 Geschützwagen Mk VI 736 (e) was the forerunner to German tracked field guns such as the Wespe and Hummel . The Germans also mobilized their anti-tank guns, using light, obsolete or captured tracked vehicles. Examples include

9009-457: Was employed throughout the Napoleonic Wars and remained in use throughout the entire 19th century and into the first half of the 20th century, when advances in weapons technology finally made it obsolete. Zamburak was a specialized form of self-propelled artillery from the early modern period . It featured small swivel guns to be mounted and fired from the back of camels. It was used by

9108-415: Was first applied to a military vehicle on the British prototype tank Little Willie . British Army officers, Colonel Ernest Swinton and Colonel Maurice Hankey , became convinced that it was possible to develop a fighting vehicle that could provide protection from machine gun fire. During World War I , Holt tractors were used by the British and Austro-Hungarian armies to tow heavy artillery and stimulated

9207-429: Was first given a physical form by Hornsby & Sons in 1904 and then made popular by Caterpillar Tractor Company , with tanks emerging during World War I . Today, they are commonly used on a variety of vehicles, including snowmobiles , tractors , bulldozers , excavators and tanks . The idea of continuous tracks can be traced back as far as the 1830s, however. The British polymath Sir George Cayley patented

9306-400: Was invented and constructed by Adolphe Kégresse and patented in 1913; in historic context rubber tracks are often called Kégresse tracks . First rubber-tracked agricultural tracked was Oliver Farm Equipment HGR in 1945-1948, which was ahead of its time and only seen small-scale production. The disadvantages of tracks are lower top speed, much greater mechanical complexity, shorter life and

9405-408: Was later purchased by Holt in 1913, allowing Holt to claim to be the "inventor" of the crawler tractor. Since the "tank" was a British concept it is more likely that the Hornsby, which had been built and unsuccessfully pitched to their military, was the inspiration. In a patent dispute involving rival crawler builder Best, testimony was brought in from people including Lombard, that Holt had inspected

9504-669: Was scrapped in 1960. The second prototype, as SU-14-1, is on display together with the T-100Y , since 1945 renamed SU-100Y , at the area #1 of the Patriot Park in Kubinka. CAMD RF 38-11355-10 "The SU-14 is a Massive Soviet SPG from the 1930s" . Tank Historia . December 28, 2022 . Retrieved December 6, 2023 . Pasholok, Yuri (December 31, 2021). "A Second Life for Obsolete Chassis" . Tankarchives.ca . Retrieved July 15, 2024 . Self-Propelled Artillery Self-propelled artillery (also called locomotive artillery )

9603-520: Was unable to build a working prototype, and his patent was voided in 1839. Although not a continuous track in the form encountered today, a dreadnaught wheel or "endless railway wheel" was patented by the British Engineer James Boydell in 1846. In Boydell's design, a series of flat feet are attached to the periphery of the wheel, spreading the weight. A number of horse-drawn wagons, carts and gun carriages were successfully deployed in

9702-502: Was under development, but, by the end of the Crimean War, the mortar was not ready for service. A detailed report of the tests on steam traction, carried out by a select Committee of the Board of Ordnance, was published in June 1856, by which date the Crimean War was over, consequently the mortar and its transportation became irrelevant. In those tests, a Garrett engine was put through its paces on Plumstead Common. The Garrett engine featured in

9801-460: Was useful for fighting nearby infantry, as a mortar is shorter-ranged and cheaper to shoot than the large main gun, as well as being better suited to wounding enemy infantry taking cover behind objects. However, since the mortar is only a secondary weapon in this case, the Merkava is not considered a mortar carrier. Self-propelled artillery remains important in the equipment of many modern armies. It saw

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