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This article is about armoured fighting vehicles. For other meanings, see Tank (disambiguation). A tank is a tracked armoured fighting vehicle, designed to engage enemy forces by the use of direct fire. A tank is characterized by heavy weapons and armour, as well as by a high degree of mobility that allows it to cross rough terrain at relatively high speeds. While tanks are expensive to operate and logistically demanding, they are among the most formidable and versatile weapons of the modern battlefield, both for their ability to engage other ground targets and their shock value against infantry. While tanks are powerful fighting machines, they seldom operate alone, being organised into armoured units in combined arms forces. Without such support, tanks, despite their armour and mobility, are vulnerable to infantry, mines, artillery, and air power. Tanks are also at a disadvantage in wooded terrain and urban environments, which cancel the advantages of the tank's long-range firepower, limit the crew's ability to detect potential threats, and can even limit the turret's ability to traverse. Tanks were first used in the First World War to break the deadlock of the trenches, and they evolved gradually to assume the role of cavalry on the battlefield. The name tank first arose in British factories making the hulls of the first battle tanks: the workmen were given the impression they were constructing tracked water containers for the British Army, hence keeping the production of a fighting vehicle secret. During WW1 two major types of tanks evolved; the "male tank" which is the vehicle associated with the word today, and the female tank. The female tank contained a series of smaller weapons located around the hull as opposed to the single large weapon seen on today's tanks, and was mainly designed as an anti-infantry platform. After WW1 ended this type of vehicle was largely replaced by infantry carriers. Tanks and armour tactics have undergone many generations of evolution over nearly a century. Although weapons systems and armour continue to be developed, many nations have reconsidered the need for such heavy weaponry in a period characterised by unconventional warfare. History Main article: History of the tank World War One: The first tanks
The interwar years: advances in design and tactics With the tank concept now established, several nations designed and built tanks between the two world wars. The British designs were the most advanced, due largely to their interest in an armoured force during the 1920s. France and Germany did not engage in much development during the early inter War years due to the state of their economy, and the Versailles Treaty respectively. The US did little development during this period because the Cavalry branch was senior to the Armoured branch and managed to absorb most of the funding earmarked for tank development. Even George S. Patton, with tank experience during WWI, transferred from the Armoured branch back to the Cavalry branch during this period (because the US Army decided not to fund a tank corps). Throughout this period several classes of tanks were common, most of this development taking place in the United Kingdom. Light tanks, typically weighing ten tons or less, were used primarily for scouting and generally mounted a light gun that was useful only against other light tanks. The medium tanks, or cruiser tanks as they were known in the United Kingdom, were somewhat heavier and focused on long-range high-speed travel. Finally, the heavy or infantry tanks were heavily armoured and generally very slow. The overall idea was to use infantry tanks in close concert with infantry to effect a breakthrough, their heavy armour allowing them to survive enemy anti-tank weapons. Once this combined force broke the enemy lines, groups of cruiser tanks would be sent through the gap, operating far behind the lines to attack supply lines and command units. This one-two punch was the basic combat philosophy of the British tank formations, and was adopted by the Germans as a major component of the blitzkrieg concept. J.F.C. Fuller's doctrine of WWI was the fount for work by all the main pioneers: Hobart in Britain, Guderian in Germany, Chaffee in the U.S., de Gaulle in France, and Tukhachevsky in the USSR. All came to roughly the same conclusions, Tukhachevsky's integration of airborne pathfinders arguably the most sophisticated; only Germany would actually put the theory to practise, and it was their superior tactics, not superior weapons, that made blitzkrieg so formidable. There was thought put into tank-against-tank combat, but the focus was on powerful anti-tank guns and similar weapons, including dedicated anti-tank vehicles. This achieved its fullest expression in the United States, where tanks were expected to avoid enemy armour, and let dedicated tank destroyer units deal with them. Britain took the same path, and both produced light tanks in the hope that with speed, they could avoid being hit, comparing tanks to ducks. In practice these concepts proved dangerous. As the numbers of tanks on the battlefield increased, the chance of meetings grew to the point where all tanks had to be effective anti-tank vehicles as well. However, tanks designed to cope only with other tanks were relatively helpless against other threats, and were not well suited for the infantry support role. Vulnerability to tank and anti-tank fire led to a rapid up-armouring and up-gunning of almost all tank designs. Tank shape, previously guided purely by considerations of obstacle clearance, now became a trade-off, with a low profile desirable for stealth and stability. The tank in World War II World War II saw a series of advances in tank design. Germany, for example, initially fielded lightly armoured and armed tanks, such as the Panzer I, which had been intended for training use only. These fast-moving tanks and other armoured vehicles were a critical element of the Blitzkrieg. However, they fared poorly in direct combat with British tanks and suffered severely against the Soviet T-34, which was superior in armour, weaponry and cross-country performance while being equal in speed. By the end of the war all forces had dramatically increased their tanks' firepower and armour; for instance, the Panzer I had only two machine guns, and the Panzer IV, the "heaviest" early war German design, carried a low-velocity 75mm gun and weighed under twenty tonnes. By the end of the war the standard German medium tank, the Panther, mounted a powerful, high-velocity 75mm gun and weighed forty-five tonnes. Another major wartime advance was the introduction of radically improved suspension systems. The quality of the suspension is the primary determinant of a tank's cross-country performance. Tanks with limited suspension travel subject their crew to massive shaking; this not only limits the speed at which the tank can travel, but also prevents firing while moving. Newer systems like the Christie or torsion bar suspension dramatically improved performance, allowing the late-war Panther to travel cross country at speeds that would have been difficult for earlier designs to reach on pavement. By this time most tanks were equipped with radios (all U.S. and German, some Soviet; British radios were common, but often of indifferent quality), vastly improving the direction of units. Tank chassis were adapted to a wide range of military jobs, including mine-clearing and combat engineering tasks. All major combatant powers also developed specialised self-propelled guns: artillery, tank destroyers, and assault guns (armoured vehicles carrying large-calibre guns). German and Soviet assault guns, simpler and cheaper than tanks, had the heaviest guns in any vehicles of the war, while American and British tank destroyers were scarcely distinguishable (except in doctrine) from tanks. Turrets, which were not previously a universal feature on tanks, were recognised as the most efficient siting of the main gun. In order to engage armoured targets the tank needed a single, powerful gun, unlike many prewar designs, which were often equipped with mulitple turrets featuring low-calibre armament, or else mounted one larger gun in a fixed position. Most tanks retained at least one hull machine gun. The Cold War and beyond After WWII, tank development proceeded largely as it had before, with improvement to both the medium and heavy classes. Light tanks were now limited to the reconnaissance role, and in U.S. use, airborne support as well. However, the weight limitations of air transport made a practical light tank almost impossible to build, and this class gradually disappeared over time. But the seeds for a true transformation had already been working their way into existing designs. A combination of better suspensions and greatly improved engines allowed late-war medium tanks to outperform early-war heavies. With only slightly more armour and somewhat larger engines to compensate, mediums were suddenly protected against almost all anti-tank weapons, even those mounted on heavy tanks, while at the same time having the mobility of a medium tank. Many consider the turning point to be the Panther, which became the inspiration for almost every tank design after it. However, the Panther was not terribly well armoured, and could not really fight the heavy tanks on an equal basis. A highly successful post-war tank was the Soviet T-54, which started production in 1947. This successor to the T-34 of World War II represented a direct evolution of that tank's design principles, improving on its low profile, good armour, high mobility, and adding a 100mm tank gun. Another new tank was the British Centurion tank. Centurion marks built in the late 1950s were able to resist hits from the infamous German 88 mm gun, were armed with the deadly 105 mm Royal Ordnance L7, and could reach 56 km/h due to the excellent 650-hp Rolls-Royce Meteor engine. The Centurion replaced all British medium cruiser tanks and finally led to the demise of the heavy infantry tank class entirely, becoming what the British referred to as the Universal Tank, soon to be known as the main battle tank in most forces, abbreviated MBT. In response to the threat of antitank guided missiles (ATGMs), the focus in development shifted away from armour thickness, to armour technology. Gun technology remained remarkably similar even to WWI-era gun technology, with most tanks in service still being manually loaded, but with big advances in shell effectiveness. Although the basic roles and traits of tanks were almost all developed by the end of WWI, the performance of twenty-first-century counterparts had increased by an order of magnitude. They had been refined dramatically in response to continually changing threats and requirements, especially the threat of other tanks. The advancing capabilities of tanks have been balanced by developments of other tanks and by continuous development of anti-tank weapons. Design The three traditional factors determining a tank's effectiveness are its firepower, mobility and protection. The psychological effect on enemy soldiers of a tank's imposing battlefield presence is called shock action. Firepower is the ability of a tank to defeat a target. This takes into account the maximum distance at which targets can be engaged, the ability to engage moving targets, the speed with which multiple targets can be attacked, and the capability to defeat armoured vehicles or entrenched infantry. Mobility includes the speed and agility of driving cross-country, the types of terrain that can be covered, the dimensions of obstacles, trenches, and water that can be crossed, the ability to cross small bridges, and the distance that can be covered before refuelling is required. "Strategic mobility" also includes the ability to travel at high speed on roads, and the ability to be carried on rail or truck transport. Traditionally AFV mobility is measured by the following metrics: Protection is the amount of armour, the type(s), how it is arranged (i.e., sloped or not), and which areas are given more protection (e.g., the turret and tracks) and which receive less (e.g., the rear of the chassis). It also includes low profile, low noise and thermal signature, active countermeasures and other methods of avoiding enemy fire, and the ability to continue fighting after damage has been sustained. Tank design is traditionally held to be a compromise between these three factors — it is not considered possible to maximise all three. For example, increasing protection by adding armour will increase weight and therefore decrease manoeuvrability; increasing firepower by using a larger gun will decrease both manoeuvrability and protection (due to decreased armour at the front of the turret). How the compromise is achieved is influenced by a combination of factors, including military strategies, budget, geography, political will, and the requirement to sell the tank to other countries. Examples of how different countries are influenced in their decisions are as follows: Weapons
Fire control Historically, tank weapons were aimed through simple optical sights and laid onto target by hand, with windage estimated or assisted with a reticle. Range to the target was estimated with the aid of a reticle (markings in the gun sight which are aligned to frame an object of known size, in this case a tank). Consequently, accuracy was limited at long range and concurrent movement and accurate shooting were largely impossible. Over time these sights were replaced with stereoscopic rangefinders, and later by Laser range-finders. Most modern main battle tanks in the armies of industrialised countries use laser range-finders but optical and reticule range-finders are still in use in older and less sophisticated vehicles. Modern tanks have a variety of sophisticated systems to make them more accurate. Gyroscopes are used to stabilise the main weapon; computers calculate the appropriate elevation and aim-point, taking input from sensors for wind speed, air temperature, humidity, the gun-barrel temperature, warping and wear, the speed of the target (calculated by taking at least two sightings of the target with the range-finder), and the movement of the tank. Infrared, light-amplification, or thermal night vision equipment is also commonly incorporated. Laser target designators may also be used to illuminate targets for guided munitions. As a result modern tanks can fire reasonably accurately while moving. Ammunition There are several types of ammunition designed to defeat armour, including High explosive squash head (HESH, also called high explosive plastic, HEP), High explosive anti-tank (HEAT), and kinetic energy penetrators (KEP, or armour-piercing discarding sabot APDS). For accuracy, shells are spun by gun-barrel rifling, or fin-stabilised (APFSDS, HEAT-FS, etc.). Some tanks, including the M551 Sheridan, T-72, T-64, T-80, T-90, T-84, and PT-91 can fire ATGMs (anti-tank guided missile) through their gun barrel or from externally mounted launchers. This functionality can extend the effective combat range of the tank beyond the range afforded by conventional shells, depending on the capabilities of the ATGM system. It also provides the tank with a useful weapon against slow, low-flying airborne targets like helicopters. The United States has abandoned this concept, phasing the M551 and M60A2 out of their forces in favour of helicopters and aircraft for long range anti-tank roles, but CIS countries continue to employ gun-missile systems in their main battle tanks. Protection
Armour
Grenade launchers, smoke and passive defences Most armoured vehicles carry smoke grenade launchers which can rapidly deploy a smoke screen to visually shield a withdrawal from an enemy ambush or attack. The smoke screen is very rarely used offensively, since attacking through it blocks the attacker's vision and gives the enemy an early indication of impending attack. Modern smoke grenades work in the infrared as well as visible spectrum of light. Some smoke grenades are designed to make a very dense cloud capable of blocking the laser beams of enemy target designators or range finders and of course obscuring vision, reducing probability of a hit from visually aimed weapons, especially low speed weapons, such as anti-tank missiles which require the operator to keep the tank in sight for a relatively long period of time. In many MBTs, such as the French-built Leclerc, the smoke grenade launchers are also meant to launch tear gas grenades and anti-personnel fragmentation grenades. Many Israeli tanks contain small vertical mortar tubes which can be operated from within the tank, enhancing the anti-personnel capabilities and allowing it to engage targets which are behind obstacles. There have been proposals to equip other tanks with dual-purpose smoke/fragmentation grenade launchers that can be reloaded from the interior. Prior to the widespread introduction of thermal imaging the most common smoke grenade in AFV launchers was white phosphorus which created a very rapid smoke screen as well as having a very useful incendiary effect against any infantry in the burst area (e.g., infantry attempting to close with hand placed charges or mines). Since the advent of thermal imagers most tanks carry a smoke grenade that contains a plastic or rubber compound whose tiny burning fragments provide better obscurant qualities against thermal imagers. Some tanks also have smoke generators which can generate smoke continuously, rather than the instantaneous, but short duration of smoke grenades. Generally smoke generators work by injecting fuel into the exhaust, which partially burns the fuel, but leaves sufficient unburned or partially burned particles to create a dense smoke screen. Modern tanks are increasingly being fitted with passive defensive systems such as laser warning devices, which activate an alarm if the tank is "painted" by a laser range-finder or designator. Other passive defences include radio warning devices, which provide warning if the tank is targeted by radar systems that are commonly used to guide antitank weapons such as millimetre and other very short wave radar. Countermeasures Passive countermeasures, like the Russian Shtora system, attempt to jam the guidance systems of incoming guided missiles. Explosive reactive armour, or ERA, is another major type of protection against high explosive antitank weapons, in which sections of armour explode to dissipate the focused explosive force of a shaped charge warhead. Reactive armour is attached to the outside of an MBT in small, replaceable bricks. Active protection systems go one step further than reactive armour. An APS uses radar or other sensing technology to automatically react to incoming projectiles. When the system detects hostile fire, it calculates a firing resolution and directs an explosive-launched counter-projectile to intercept or disrupt the incoming fire a few metres from the target. Exposed crew
Mobility There are essentially three main aspects of mobility to consider, the tank's basic mobility such as its speed across terrain, the ability to climb obstacles and its overall battlefield mobility such as range, what bridges it can cross, and what transport vehicles can move it and turning. Mobility is what tankers and tank designers call 'agility'. Mobility of a tank is categorised as Battlefield Mobility, Tactical Mobility, or Strategic Mobility. The first is a function of its engine performance and capability of its running gear and is determined by aspects such as acceleration, speed, vertical obstacle capability and so on. The second is the ability of the tank to be readily transported within a theatre of operation. The third is its ability to be transported from one theatre of operation to other, dependent on its weight, air portability and so on. A main battle tank is designed to be very mobile and able to tackle most types of terrain. Its wide tracks disperse the heavy weight of the vehicle over a large area, resulting in a specific ground pressure that might be lower than that of a man's foot . The types of terrain that do pose a problem are usually extremely soft ground such as swamps, or rocky terrain scattered with large boulders. In "normal" terrain, a tank can be expected to travel at about 30 to 50 km/h. The road speed may be up to 70 km/h. The logistics of getting from point A to point B are not as simple as they appear. On paper, or during any test drive of a few hours, a single tank offers better off-road performance than any wheeled fighting vehicle. On the road the fastest tank design is not much slower than the average wheeled fighting vehicle design. But in practice, the huge weight of the tank combined with the relative weakness of the track assembly makes the maximum road speed of a tank really a burst speed, which can be kept up for only a short time before there is a mechanical breakdown. Although the maximum off-road speed is lower, it cannot be kept up continuously for a day, given the variety and unpredictability of off-road terrain (with the possible exception of plains and sandy deserts). Since an immobilised tank is an easy target for mortars, artillery, and the specialised tank hunting units of the enemy forces, speed is normally kept to a minimum, and every opportunity is used to move tanks on wheeled tank transporters and by railway instead of under their own power. Tanks invariably end up on railcars in any country with a rail infrastructure, because no army has enough wheeled transporters to carry all its tanks. Planning for railcar loading and unloading is crucial staff work, and railway bridges and yards are prime targets for enemy forces wishing to slow a tank advance. When moving in a country or region with no rail infrastructure and few good roads, or a place with roads riddled by mines or frequent ambushes, the average speed of advance of a tank unit in a day is comparable to that of a man on a horse or bicycle. Frequent halts must be planned for preventive maintenance and verifications in order to avoid breakdowns during combat. This is in addition to the tactical halts needed so that the infantry or the air units can scout ahead for the presence of enemy antitank groups. Another mobility issue is getting the tank to the theatre of operations. Tanks, especially main battle tanks, are extremely heavy, making it very difficult to airlift them. Using sea and ground transportation is slow, making tanks problematic for rapid reaction forces. Some tank-like vehicles use wheels instead of tracks in order to increase road speed and decrease maintenance needs. These vehicles lack the superior off-road mobility of tracked vehicles, but are considered by United States planners as more suited for rapid reaction forces due to increased strategic mobility . Water operations For most tanks water operations are limited to fording. The fording depth is usually limited by the height of the air intake of the engine, and to a lesser extent the driver's position. The typical fording depth for MBTs is 90 to 120 cm. (3-4 Feet.) Deep fording However, with preparation some tanks are able to ford considerably deeper waters. The West German Leopard I and Leopard II tanks can ford to a depth of several metres, when properly prepared and equipped with a snorkel. The Leopard snorkel is in fact a series of rings which can be stacked to create a long tube. This tube is then fitted to the crew commander's hatch and provides air and a possible escape route for the crew. The height of the tube is limited to around three meters. Some Russian/Soviet tanks are also able to perform deep fording operations, however unlike the Leopard, the Russian snorkel is only a few inches round and does not provide a crew escape path. Russian snorkels are also fixed in length, providing only a couple of metres of depth over the turret height. This type of fording requires careful preparation of the tank and the ingress and egress sites on the banks of the water obstacle. Tank crews usually have a negative reaction towards deep fording. This has influenced tactics in those countries where the psychological health of the crews or their capacity for rebellion is taken into account. However, if properly planned and executed this type of operation adds considerable scope for surprise and flexibility in water crossing operations. Amphibious tanks
Power plants
Multi-fuel diesels All modern non-turbine tanks use a diesel engine because diesel fuel is less flammable and more economical than petrol. Some Soviet tanks used the dark smoke of burning diesel as an advantage and could intentionally burn fuel in the exhaust to create smoke for cover. Fuel tanks are commonly placed at the rear of the tank, though in some designs, such as the Israeli Merkava, the diesel fuel tanks are placed around the crew area to provide an additional layer of "armour." Fuel has often been stored in auxiliary tanks externally, or by other means such as in a small trailer towed behind the tank, able to be detached during combat. Modern tank engines are in some cases multi-fuel engines, which can operate on diesel, petrol or similar fuels. Gas turbines Gas turbine engines have been used as an auxiliary power unit (APU) in some tanks, and are the main power plant in the Soviet/Russian T-80 and U.S. M1 Abrams. They are comparatively lighter and smaller than diesel engines; at the same level of sustained power output (the T-80 was dubbed the Flying Tank for its high speed). However they are much less fuel efficient, especially at low RPMs, requiring larger fuel tanks to achieve the same combat range. Different models of the M1Abrams have addressed this problem with battery packs or secondary generators to power the tank's systems while stationary, saving fuel by reducing the need to idle the main turbine. T-80 tanks are commonly seen with large external fuel tanks to extend their range. Russia has replaced T-80 production with the less powerful T-90 (based on the T-72), while Ukraine has developed the diesel-powered T-80UD and T-84 with nearly the power of the gas-turbine tank. Because of their lower efficiency, the thermal signature of a gas turbine is higher than a diesel engine at the same level of power output. On the other hand the acoustic signature of a tank with a muffled gas turbine can be quieter than a piston engine–powered one. The M1A2 was nicknamed Whispering Death for its quiet operation.• A turbine is theoretically more reliable and easier to maintain than a piston-based engine, since it has a simpler construction with fewer moving parts. In practice, however, those parts experience a higher wear due to their higher working speeds. The turbine blades are also very sensitive to dust and fine sand, so that in desert operations special filters have to be carefully fitted and changed several times daily. An improperly fitted filter, or a single bullet or piece of shrapnel can render the filter useless, potentially damaging the engine. Piston engines also need well-maintained filters, but they are more resilient if the filter does fail. Like most modern diesel engines used in tanks, gas turbines are usually multi-fuel engines. Sonic, seismic, and thermal traces
Command, control, and communications Commanding and co-ordinating a tank organisation in the field has always been subject to particular problems. Because of the isolation of small units, individual vehicles, and even the crewmen of a tank, special arrangements have had to be made. Armoured bulkheads, engine noise, intervening terrain, dust, and smoke, and the need to operate "hatches down" (or "buttoned up") comprise severe detriments to communications. Every action of a tank's crew, movement and fire, is ordered by its commander. In some early tanks, the crew commander's task was severely hampered by having to load or fire the main armament, or both. In many small armoured fighting vehicles, even into the late twentieth century, the crew commander would relay movement orders to the driver by kicks to his shoulders and back. Most modern AFVs are equipped with an intercom, allowing all crew members to talk to each other, and to operate the radio equipment. Some tanks have even been equipped with an external intercom on the rear, to allow co-operating infantry to talk to the crew. In the earliest tank operations, communications between the members of an armoured company were accomplished using hand signals or handheld semaphore flags, and in some situations, by crew members dismounting and walking to another tank. In World War One, situation reports were sent back to headquarters by releasing carrier pigeons through vision slits. Signal flares, smoke, movement, and weapons fire are all used by experienced crews to co-ordinate their tactics. From the 1930s to the '50s, most nations' armoured forces became equipped with radios, but visual signals are still used to reduce radio chatter. A modern tank is usually equipped with radio equipment allowing its crew to communicate on a company or battalion radio network, and possibly to monitor a higher-level network, to co-ordinate with other arms of service. Company or battalion commanders' tanks usually have an additional radio. Communications on a busy network are subject to a set of formalised language rules called radio voice procedure. Most armoured forces operate with the crew commander, and possibly other crew members, "hatches up", for best possible situational awareness. When taking fire, or in potential NBC conditions, tank crews "button up" and only view the battlefield through vision slits or periscopes, severely reducing their ability to acquire targets and perceive hazards. Since the 1960s, a tank's commander has had progressively more sophisticated equipment for target acquisition. In a main battle tank, the commander has his own panoramic sights (with night-vision equipment), allowing him to designate one or more new targets, while the gunner engages another. More advanced systems allow the commander to take control of the turret and fire the main armament in an emergency. A recent development in AFV equipment is the increased integration of fire control, the laser range-finder, GPS data, and digital communications. U.S. tanks are fitted with digital computers which are connected into battlefield networks. These integrate known information on enemy targets and friendly units to greatly improve the tank commander's situational awareness. In addition to easing the reporting burden, these systems also allow for orders to be given complete with graphics and overlays, via the network. See also: Vulnerability Despite being a powerful weapon and an impressive sight on the battlefield, the tank is vulnerable. In fact, the tank's superiority has led to massive development of antitank weapons. When the anti-tank helicopter arrived (able to attack the more lightly armoured top of the tank), some claimed that the tank was essentially obsolete. There has not been tank and helicopter combat between evenly matched forces for many years, so this conclusion may be premature. Infantry The tank is still vulnerable to infantry, especially in close country or built up areas. The armour and mobility of tanks also make them large and noisy. This can allow enemy infantry to spot, track and evade tanks until an opportunity presents itself for a counter-attack. Since heavy tank losses in some Second World War arenas, tank tactics have generally included close infantry support. Because tank crews have limited visibility, it is relatively easy for veteran infantry to get close to a tank, especially if the hatch is closed. If a crew member opens the hatch for the better visibility, he can be shot. An infantryman cannot be targeted by a tank's weapons when close, as the main gun and coaxial machine gun cannot depress sufficiently. Where tanks are operating in groups, this is less of a problem, since they can call on nearby tanks to drive off the infantry with light weapons. Whilst many handheld infantry anti-tank rockets, missiles and grenades will not penetrate the front armour of a tank, they may penetrate the less heavily armoured top, rear and perhaps the sides. Damage to the running gear can inflict a mobility kill. Tanks are also vulnerable to hand-placed anti-tank mines. Infantry have even immobilised tanks using a set of plates covered with leaves and dirt as dummy mines (the ruse being augmented by the crew's obscured vision). The infantry can then attack the tank while stopped. This tactic was taught to the British Home Guard during the Second World War since the Home Guard was not often provided with long-range anti-tank weapons. In addition, in built-up areas the tank is very vulnerable to attack from above and sometimes from below, as the top and floor of the tank have the weakest armour. Artillery Conventional artillery shells are not very effective against tank armour, except a direct hit by a sufficiently powerful shell. A non-penetrating shell can still disable a tank through dynamic shock, internal armour shattering or simply overturning the tank. In the last thirty years, however, a variety of artillery projectiles have been developed specifically to attack tanks. These include laser-guided projectiles, such as the US's now cancelled Copperhead CLGP (Cannon Launched Guided Projectile), which virtually guarantees a direct hit. Some of these CLGP's (such as the Copperhead) have HEAT warheads instead of common HE. Guided and unguided scatter munitions and submunitions have also been developed: a single artillery shell containing a number of smaller munitions designed to attack a tank. A six-gun battery might be able to fire several hundred submunitions in a minute or two. In one form, the shell bursts in the air above the tank and a number of shaped charge (HEAT) or HEDP (High Explosive Dual Purpose) bomblets or grenades rain down. Any that hit the tank have a good chance of causing damage, since they are attacking the thin top armour. Another form scatters a number of small anti-tank mines in the tank's path, which probably will not penetrate the armour but can damage a track, leaving the tank immobile and vulnerable. More sophisticated are submunitions with a homing capability. Once again the shell explodes above the tank position and dispenses a number of submunitions. The munitions contain some circuitry to identify tanks, such as IR or millimetre radar; when a tank is identified, a rocket propellant is fired to shoot the projectile at the tank. These munitions will often descend by parachute, to allow time for target acquisition and attack. All of the above but the CLGP can be fired from medium (122/152/155-mm) artillery, both tube and rocket. There has also been development of large calibre (81-mm and larger) guided mortar munitions with both internal (e.g., IR or radar) or external (i.e. laser designator) guidance. Helicopters The single biggest threat to the tank today is the anti-tank helicopter armed with ATGWs (Anti-Tank Guided Weapons) or anti-tank cannons. The helicopter can position itself where it is not easily seen from a tank and then attack from any quarter. The limited visibility from a closed-down tank makes sighting a helicopter harder. Most helicopter-launched ATGWs have sufficient range that they can under the right conditions be fired at a range too long for the tank to retaliate with its own weapons. This may change: it is believed that some countries are developing anti-helicopter weapons that can be fired from a main gun. Some tank gunnery systems are also probably capable of hitting a hovering or slow-moving helicopter at considerable range. Even the light cannon of a helicopter gunship can be effective, as it can target the thinner top armour of the tank. Although putting weapons on helicopters (probably) dates back to the 1955 with the Bell 47; the first specific anti-tank, attack helicopter that went into mass production was the Bell AH-1 Cobra in 1966. Mines Mines have the advantage of attacking the thinnest armour of the tank and can be well concealed. With modern scatterable mines, and in particular artillery scatterable mines, it is actually possible to lay a mine field around a moving tank formation. In addition to the traditional bottom-attack mine, the scatter mine, the artillery-delivered mine and the air-delivered mine, there are a number of side attack or "off-route" mines. These are mines that can be mounted on a vertical surface (such as a wall) or mounted on a stand, and are positioned where a tank is likely to pass. Choke points such as bridges, fords, gates and underpasses are all likely spots. When a tank passes, these mines fire into the side of the tank. The two common warheads for these mines are the ubiquitous HEAT and the less-common platter charge. These mines can be fired by a human operator, simple mechanical actuator (such as a tripwire or pressure plate) or by more sophisticated systems (such as seismic, IR or other electronic fusing systems). Some of the fusing systems are sophisticated enough to discriminate between different classes of target and attack only specified classes of vehicles (e.g., ignore wheeled vehicles). Some infantry anti-tank weapons can also be configured to act as off-route mines. Aircraft Starting in WW2 with the Hawker Hurricane MK. IID, the Hawker Typhoon, the Henschel Hs 129, the Ilyushin Il-2, and the Junkers 87 Stuka G-1 and G-2; many aircraft, including the A-10 Thunderbolt II and SU-25 Frogfoot, have been specifically built for close air support, including tank destruction. They can use weapons similar to helicopters, large caliber anti-tank guns, air-to-surface missiles ( i.e. AGM-65 Maverick), and various bombs -- unguided or laser-guided and with or without submunitions. Logistics Tanks use tremendous amounts of fuel even when standing still, and even on the move, gas consumption of 1 mile per gallon (aprox. 600 litres/100 km.) is typical. As such, the operation of tank divisions requires well planned logistical support. A common tactic when dealing with tanks is to ignore the tanks themselves and to attack the more vulnerable supply lines. This tactic was used effectively by the Chinese Army during the Korean War to force American tank divisions to retreat from the Yalu River. Tanks are also difficult to maintain in the field, particularly in areas of extreme heat, extreme cold or in muddy conditions. These shortcomings came into focus during the German invasion of Poland in 1939. Although German forces faced little adequately armed opposition, one of the most important lessons learned was that the tanks consumed fuel at a far greater rate in actual combat conditions than they did in maneuvers. This proved to be a valuable lesson for the Battle of France the following year. On the Russian Front, the Germans often found that it was nearly impossible to start tanks in the cold of a Russian winter. One common method was to set a fire underneath the tank, but this method was time consuming and left the tank vulnerable to attack. In desert warfare, tanks are often subject to overheating due to their requirements for water as a coolant for their radiators. Tanks are also restricted to operations on certain types of terrain. For example, they are unable to operate well on soft soil such as polder, in mountainous or rocky terrain, or in the woods. As such, tank operations are often limited to well defined roads that are succeptible to mining. The future of tanks through research and development Main article: Tank research and development There has been much speculation as to how tanks will evolve for modern day conflicts. Current research involves making the tank invisible to radar by adapting stealth technologies originally designed for aircraft and a variety of luminosity and colour shaping technologies. Research is also ongoing in armour systems and new propulsion units. One clear trend is the increasing number of electrical and communication systems on a tank, such as thermal scopes and higher powered radios. If tank designs switched to electrical motors like some other heavy construction equipment, rather than a direct drive transmission, or used electromagnetic guns, as is being studied for ships, there would still be a need for a good power-plant. The turbine engine and diesel (or multi-fuel) power plants meet current power needs but it is also possible that other types of power-plants such as fuel cells will provide a viable option, and they have been experimented with. For example, a hybrid electric version of the M113 APC outperformed the conventional one in many areas, but only at the expense of smaller range. Reduction of signatures and multi-fuel capability give the Stirling engine an advantage, and it has been examined. See also Armoured warfare and tactics Armoured fighting vehicles Notes | |||||||||||||||||||||||
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