TankA tank is a tracked armoured fighting vehicle, designed primarily 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 organized 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 and limit the crew's ability to detect potential threats. Tanks were first used in the First World War to break the deadlock of the trenches, and they evolved to gradually 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. 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 been reconsidering the need for such heavy weaponry in a period characterised by unconventional warfare. HistoryWorld War One: The first tanksHaving already seen Rolls Royce armoured cars used by Royal Naval Air Service in 1914, and aware of schemes to create a tracked fighting vehicle, First Lord of the Admiralty Winston Churchill sponsored the Landships Committee to oversee development of this new weapon. The first successful prototype tank, nicknamed Little Willie, was tested for the British Army on September 6, 1915. Although initially termed landships by the Admiralty, the initial vehicles were colloquially referred to as water-carriers, later shortened to tanks, to preserve secrecy. The word tank was used to give the workers the impression they were constructing tracked water containers for the British army in Mesopotamia, and it was made official on December 24, 1915. This German photograph from World War I shows a captured British Mark II tank. The front part of the tracks are high off the ground in order to climb obstacles. The main guns are side-mounted to keep the centre of gravity lowThe first tank became operational when Captain H. W. Mortimore of the Royal Navy took a Mark I into action at Delville Wood during the Battle of the Somme on September 15, 1916. The French developed the Schneider CA1 working from Holt caterpillar tractors, and first used it on April 16, 1917. The first successful use of massed tanks in combat occurred at the Battle of Cambrai on November 20, 1917. The tank would eventually make trench warfare obsolete, and the thousands of tanks fielded during the war by French and British forces made a significant contribution. Initial results with tanks were mixed, with problems in reliability (and impatient high command) causing considerable attrition in combat. Deployment in small groups also lessened their tactical value and impact, which was still formidable during first encounters. German forces suffered from shock and lacked counter-weapons, though they did (accidentally) discover solid anti-tank shot, and the use of wider trenches to limit the British tanks' mobility. Changing battlefield conditions and continued unreliability forced Allied tanks to continue evolving for the duration of the war, producing models such as the very long Mark V, which could navigate large obstacles, especially wide trenches, more easily than many modern armoured fighting vehicles (AFVs). Germany fielded a small number of tanks, mainly captured, during World War I. They only produced approximately twenty of their own design, the A7V. Demands from infantry to have tanks close by during attacks would have pernicious effects on British tank design and tactics well into WW2. |
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 armored force during the 1930s. 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 Armored 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 Armored branch back to the Cavalry branch during this period.
Throughout this period several classes of tanks were common, most of this development taking place in the United Kingom. 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 focussed 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 antitank 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 antitank guns and similar weapons, including dedicated antitank 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 antitank 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.
World War II saw a series of advances in tank design. Germany for example, initially fielded lightly armoured and lightly 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 and weaponry. 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. Although this might not sound important, 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, making operation difficult, limiting speed, and making firing on the move practically impossible. 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 way forward. It was appreciated that if the tank's gun was to be used to engage armoured targets then it needed to be as large and powerful as possible, making having one large gun with an all-round field of fire vital. Multiple-turreted tank designs like the Soviet T-35 were abandoned by World War II. Most tanks retained at least one hull machine gun. Even post-war, the M60 MBT had a smaller secondary turret for the commander's cupola.
After WWII, tank development proceeded largely as it had before, with improvements 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 antitank 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 basis 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 Soviet T-34 tank being examined by curious citizens in the 1956 Hungarian RevolutionThe first tank to 'get it all right' is generally considered to be the British Centurion tank, which (in its later versions) was able to take hits from the infamous German 88 mm gun, was armed with the deadly 105 mm Royal Ordnance L7 that was superior to anything in the field, and could reach 56 km/h due to its excellent 650-hp Rolls-Royce Meteor engine. The Centurion replaced all British medium cruiser tanks and 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 armor thickness, to armor 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 antitank weapons.
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:
Further information: tank classification
The main weapon of any modern tank is a single large gun. Tank guns are among the largest-calibre weapons in use on land, with only a few artillery pieces being larger. Although the calibre has not changed substantially since the end of the Second World War, modern guns are technologically superior. The current common sizes are 120mm calibre for Western tanks and 125mm for Eastern (Soviet and Chinese legacy) tanks. Tank guns have been able to fire many types of rounds, but their current use is commonly limited to kinetic energy (KE) penetrators and high explosive (HE) rounds. Some tanks can fire missiles through the gun. Smoothbore (rather than rifled) guns are the dominant type of gun today. The British Army and the Indian Army are now the only ones to field main battle tanks carrying rifled guns.
Modern tank guns are generally fitted with thermal jackets which reduce the effect of uneven temperature on the barrel. For instance, if it were to rain on a tank barrel the top would cool faster than the bottom, or a breeze on the left might cause the left side to cool faster then the right. This uneven cooling will cause the barrel to bend slightly and will affect long range accuracy.
Usually, tanks carry other armament for short range defence against infantry or targets where the use of the main weapon would be ineffective or wasteful. Typically, this is a small calibre (7.62 to 12.7 mm) machine gun mounted coaxially with the main gun. However, a couple of French tanks such as the AMX-30 and AMX-40 carry a coaxial 20mm cannon that has a high rate of fire and can destroy lightly armoured vehicles. Additionally, many tanks carry a roof-mounted or commander's cupola machine gun for close-in ground or limited air defence. The 12.7-mm and 14.5-mm machine guns commonly carried on US and Russian tanks and the French Leclerc are also capable of destroying lightly-armoured vehicles at close range.
Some tanks have been adapted to specialised roles and have had unusual main armament such as flame-throwers. These specialised weapons are now usually mounted on the chassis of an armoured personnel carrier.
Historically, tank weapons were aimed through simple optical sights and laid onto target by hand, with windage estimated or assisted with a reticule. Range to the target was estimated with the aid of a reticule (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 range-finders. These were eventually replaced 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.
There are several types of ammunition designed to defeat armour, including High explosive squash head (HESH, also called high explosive plastic, HEP), High explosive antitank (HEAT), and kinetic energy penetrators (KEP, or armour-piercing discarding sabot APDS). For accuracy, shells are spun by gun-barrel rifling, or fin-stabilized (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.
The main battle tank is the most heavily armoured vehicle in modern armies. Its armour is designed to protect the vehicle and crew against a wide variety of threats. Commonly, protection against kinetic energy penetrators fired by other tanks is considered the most important. Tanks are also vulnerable to antitank guided missiles; antitank mines, larger bombs, and direct artillery hits, which can disable or destroy them. Tanks are especially vulnerable to airborne threats. Most modern MBTs do offer near complete protection from artillery fragmentation and lighter antitank weapons such as rocket propelled grenades. The amount of armour needed to protect against all conceivable threats from all angles would be far too heavy to be practical, so when designing an MBT much effort goes into finding the right balance between protection and weight.
Challenger 2 tank, fitted with Chobham ArmourMost armoured fighting vehicles are manufactured of hardened steel plate, or in some cases aluminium. The relative effectiveness of armour is expressed by comparison to rolled homogeneous armour.
Most armoured vehicles are best-protected at the front, and their crews always try to keep them pointed toward the likeliest direction of the enemy. The thickest and best-sloped armour is on the glacis plate and the turret front. The sides have less armour and the rear, belly and roof are least protected. World War II American M4 Medium tank crews found the German Tigers to be practically invulnerable from the front, and were forced to employ flank attacks. Today, tanks are vulnerable to specialised top-attack missile weapons and air attack. During WW2, aircraft rockets earned a formidable reputation, especially in France after the Normandy landings (Operation Neptune); post-war analysis revealed many reported kills were near-misses. Aircraft cannon firing armour-piercing ammunition, such as the Hurribomber's 40mm or Stuka's 37mm, could be effective, also. Even a simple Molotov cocktail on the engine deck, however, may disable or destroy most tanks.
Before the Second World War, several tank designers tried sloping the armour on experimental tanks. The most famous and successful example of this approach at the time was the T-34. Angling armour plates greatly increases their effectiveness against projectiles, by increasing the effective perpendicular thickness of the armour, and by increasing the chance of deflection. German tank crews were said to be horrified to find that shots fired at the angled plates of T-34s would sometimes simply ricochet.
Even light infantry antitank weapons can immobilise a tank by damaging its suspension or track. Many tracked military vehicles have side skirts, protecting the suspension.
High explosive antitank weapons (HEAT), such as the bazooka, were a new threat in the Second World War. These weapons carry a warhead with a shaped charge, which focuses the force of an explosion into a narrow penetrating stream. Thin plates of spaced armour, steel mesh "RPG screens", or rubber skirts, were found to cause HEAT rounds to detonate too far from the main armour, greatly reducing their penetrating power.
Some antitank ammunition (HESH or HEP) uses flexible explosive material, which squashes against a vehicle's armour, and causes dangerous spalling of material inside the tank when the charge explodes. This may kill the crew without penetrating the armour, still neutralizing the tank. As a defence, some vehicles have a layer of anti-spall material lining their insides.
Since the 1970s, some tanks have been protected by more complex composite armour, a sandwich of various alloys and ceramics. One of the best types of passive armour is the British-developed Chobham armour, which is comprised of spaced ceramic blocks contained by a resin-fabric matrix between layers of conventional armour. A form of Chobham armour is encased in depleted uranium on the very well-protected M1A1 Abrams MBT.
The Israeli Merkava tank takes the design of protection systems to an extreme, using the engine and fuel tanks as secondary armour (back-up armour).
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 antitank 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.
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 focussed 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.
Paradoxically, a tank is usually in its safest state when the commander is in a personally unsafe position, riding in the open, head out of the turret, with no personal protection save his helmet and a flak jacket. In this rather high position the commander can see around the vehicle with no restrictions, and has the greatest chance of spotting enemy antitank operations or natural and unnatural obstacles which might immobilise or slow down the tank. Tank periscopes and other viewing devices give a sharply inferior field of vision and sense of the countryside, despite constant advances in optics and electronics. Thus, when a tank advances in hostile territory with hatches closed, the commander and the crew might be personally safer, but the tank as a whole is more at risk given the extremely reduced vision. Improvements in onboard optical systems are ongoing, in order to overcome this problem.
There are essentially two main aspects of mobility to consider, the tank's basic mobility such as its speed across terrain and ability to climb obstacles, and its overall battlefield mobility such as range, what bridges it can cross, and what transport vehicles can move it. 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.
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.
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.
Some light tanks such as the PT-76 are amphibious, typically being propelled in the water by hydrojets or by their tracks.
Often a fold down trim vane is erected to stop water washing over the bow of the tank and thus reducing the risk of the vehicle being swamped via the driver's hatch.
In World War II the M4 Medium (Sherman) tank was made amphibious with the addition of a rubberised canvas screen to provide additional buoyancy. It was propelled by propellers driven by the main engine. This was referred to as the Sherman DD (Duplex Drive) and was used on D-Day to provide close fire support on the beaches during the initial landings. The Sherman DD could not fire when afloat as the buoyancy screen was higher than the gun. A number of these DDs sank due to rough weather in the Channel (having been launched too far out). Those that did make it ashore, however, provided essential fire support in the first critical hours, getting off the beaches.
The tank's power-plant supplies power for moving the tank and for other tank systems, such as rotating the turret or electrical power for a radio. Tanks fielded in WWI mostly used petrol (gasoline) engines as power-plants, unlike the American Holt Gas-Electric tank which was powered by a petrol (gasoline) engine and an electric engine. In the Second World War there was a mix of power-plant types used; a lot of tank engines were adapted aircraft engines. As the Cold War started, tanks had almost all switched over to using diesel, improved multi-fuel versions of which are still common. Starting in the late 1970s, turbine engines began to appear.
The weight and type of power-plant (influenced by its transmission and drive train) largely determines how fast and mobile the tank is, but the terrain effectively limits the maximum speed of all tanks through the stress it puts on the suspension and the crew.
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.
The Chinese type 99 main battle tankGas 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. Newer models of the M1 have a small secondary turbine engine as an APU 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.[1]
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.
Stationary tanks can be well camouflaged in woodland and forested areas where there is natural cover, making detection and attack from the air more difficult. By contrast, in the open it is very hard to hide a tank. In both cases, however, once a tank starts its engine or begins to move it can be detected much more easily due to the heat and noise generated by its engine. The tank tracks across lands can be spotted from the air, and in the desert movement can stir up vast dust clouds several times the size of the tanks.
A recently stopped stationary tank has a considerable heat signature. Indeed even if the tank itself is hidden, for example behind a hill, it is still possible for a skilled operator to detect the tank from the column of warmer air above the tank. This risk can be reduced somewhat by the use or thermal blankets which reduce the radiation of heat while the engine and tracks cool. Some camouflage nets are manufactured from unevenly distributed mix of materials with differing thermal properties, which are designed to "randomise" or at least reduce the regularity of the thermal signature of a tank.
Tanks are powered by a diesel or turbine engine of a power comparable to a diesel locomotive. From the outside a diesel powered tank smells, sounds, and feels quite like a diesel locomotive. The deep rumble of even a single tank can be heard a great distance on a quiet day, and the sharp diesel smell can be carried far downwind. When a tank stands still with engine running the land trembles around it. When moving, the vibrations are greater. The acoustic and seismic signatures of multi-fuel engines are comparable. The acoustic signature of a turbine engine is much greater: its high-pitched whine can be much more easily distinguished from other sounds, near or far.
The very large power output of modern tank engines (typically in excess of 750kW or 1,000hp) ensure that they produce a distinct thermal signature. The unusually compact mass of metal of the tank hull dissipates heat in a fashion which marks it off sharply from other objects in the countryside. A moving tank is thus relatively easy to spot by good land-based or aerial infrared scanners. One of the reasons for the one-sided fighting during the Gulf War was that tanks like M1 Abrams had almost four times the night-time infrared scanning range of T-72s used by the Iraqi army. Another factor in the Gulf War was that, even when camouflaged and not moving, Iraqi tanks at night would cool at a different rate from their surroundings, making thermal detection easier.
Getting a tank to move proved to be important in the Kosovo conflict in 1999. During the initial few weeks of the conflict NATO air sorties were rather ineffective in destroying Serbian tanks. This changed in the final week of the conflict, when the Kosovo Liberation Army began to engage tanks. Although the KLA had little chance of destroying the tanks, their purpose was to get the tanks to move whereupon they could be more easily identified and destroyed by NATO air power.
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:
Whilst being a tremendously powerful weapon and the undoubted king of the land battlefield, the tank is not invulnerable. In fact it is the tank's superiority which has focused so much effort on improving antitank weapons.
The tank is still vulnerable to infantry, especially in close country or built up areas. The armour and mobility of tanks, while usually notable assets, also makes them large and noisy. This can give enemy infantry the initiative, allowing them to spot, track and evade tanks until an opportunity presents itself for a stealthy counter-attack. This is why modern tactics insist on tanks being closely supported by friendly infantry.
For veteran troops, it is relatively easy for an infantry man to get close to a tank, especially if it is fully closed down (that is, the commander is fully inside the turret) as tanks have very poor visibility close in and especially to the sides and rear, unless the turret is pointing in that direction. If the crew commander is not closed down, that is, has exposed his head and perhaps upper body for the better view it affords him, then he can of course be shot.
In theory, it is easy for an infantry man to lie prone, wait behind a tree or other handy cover or inside a building and to quickly dash out as a tank passes. However, the tank is a fearsome war machine; it takes confidence, discipline and training to carry this out.
Once an infantry man is close to a tank he cannot be targeted by its main weaponry unless the crew expose themselves to attack him, as the main gun and coaxial machine gun can not depress sufficiently to engage the close-in infantry man. Where tanks are operating in groups this is less of a problem, since they can call on nearby tanks to fire on themselves with machine guns and other light weapons which are unlikely to damage a tank but which will drive off infantry.
Whilst many handheld infantry antitank rockets, missiles and grenades will not penetrate the front armour of a tank, they will, generally speaking, penetrate the weaker, rear, top and perhaps sides, as well as being able to easily damage the running gear to inflict an "M" (mobility) kill. Tanks are also vulnerable to hand placed antitank mines.
In addition in built up areas the tank is very vulnerable to attack from above—the roof and floor of the tank being traditionally the thinnest and weakest armoured surfaces.
Traditionally, conventional artillery has not been very effective against tanks as the tank's armour could withstand any artillery round except a direct hit. Even though a shell may not penetrate a tank's armour, it can still disable it through dynamic shock, internal armor shattering, or simply overturning the tank.
In the last thirty years however, a variety of artillery projectiles have been developed with attacking tanks in mind. These include laser guided projectiles, such as the US Copperhead CLGP (Cannon Launched Guided Projectile) which virtually guarantees a direct hit on the thin top armour. In addition some of these CLGP's such as the Copperhead have HEAT warheads instead of common HE.
In addition to achieving a direct hit with guided projectiles, guided and unguided scatter munitions and submunitions have been developed: a single artillery shell containing a number of smaller munitions designed to attack a tank. At its simplest the shell bursts in the air and a number of shaped charged (HEAT) or HEDP (High Explosive Dual Purpose) bomblets or grenades rain down, with luck hitting the tank. If they do hit it will likely cause damage, despite their small size, since they are attacking the thin top armour.
A variation on this theme is replacing the top attack munitions with small antitank mines, which probably won't penetrate the armour but will blow off a track, leaving the tank vulnerable for destruction by other means.
A six-gun battery might be able to fire several hundred submunitions into an area in a minute or two.
More sophisticated are submunitions with a homing capability. Once again the shell explodes above the tank position and dispenses a (usually smaller) number of submunitions. The munitions contain some circuitry to identify tanks, such as IR or millimetre radar. In order to allow the munitions time to use its sensor the munitions will often be deployed under a parachute. When a tank is identified a rocket is fired to direct the projectile at the tank.
All of the above bar the CLGP can be fired from medium (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 for attacking tanks.
The single biggest threat to the tank today is the antitank helicopter armed with ATGWs (Anti-Tank Guided Weapons) or cannon. The helicopter can typically fire from behind cover, using its greater mobility to attack from an unexpected quarter.
In addition most helicopter launched ATGWs have sufficient range that they can under the right conditions fire from ranges where the tank itself can not easily retaliate with its own weapons (though it is believed that some countries are developing anti-helicopter weapons that can be fired from a main gun and some tank gunnery systems are probably capable of hitting a hovering or slow moving helicopter at considerable range). In addition even the light cannon of the helicopter gunship can be effective as they can attack the thin top armour of the tank.
The tank is still vulnerable to mines. Mines have the advantage of attacking the thinnest armour of the tank and can be well concealed.
In addition with modern scatterable mines, and in particular artillery scatterable mines, it is actually possible to lay a mine field around a moving tank formation.
As well as the traditional bottom attack mine, the scatter mine, the artillery delivered mine, or air delivered mine, there are also a number of side attack or "off route" mines available. These are mines that can be mounted on a vertical surface such as a wall, or tree, or mounted on a stand and are intended to be aimed at a road, track to other point a tank is likely to pass. Choke points such as bridges, fords, gates, underpasses, etc. are all likely spots. When the tank passes they fire into the side of the tank. The two common warheads for these mines are the ubiquitous HEAT and less commonly a 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 be able to discriminate between different classes of target and only attack specified classes of vehicles, e.g., ignore wheeled vehicles. Obviously a well placed off route mine will attempt to attack the rear or at worst the side of the tank, if at all possible. Some infantry antitank weapons can also be configured to act as off-route mines.
Many aircraft, including the A-10 Thunderbolt II and SU-25 Frogfoot, have been specifically built for close air support, which in many cases include destroying tanks.
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.
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Reduction of signatures and multi-fuel capability give the Stirling engine an advantage, and it has been examined. Other names for tourmalines:. 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. Ironically the rarest variety, colourless achroite, is not appreciated and is the least expensive of the transparent tourmalines. 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. In jewellery, blue indicolite is the most expensive, followed by green verdelite and pink rubellite. 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. Tourmaline is used in jewelry, pressure gauges, and specialist microphones. One clear trend is the increasing number of electrical and communication systems on a tank, such as thermal scopes and higher powered radios. Also, tourmaline is a durable mineral and can be found in minor amounts as grains in sandstone and conglomerate. Research is also ongoing in armour systems and new propulsion units. Magnesium-rich tourmalines, dravites, are generally restricted to schists and marble. 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. Schorl and lithium-rich tourmalines are usually found in granite and granite pegmatite. There has been much speculation as to how tanks will evolve for modern day conflicts. Igneous rocks, in particular granite and granite pegmatite and in metamorphic rocks such as schist and marble. Many aircraft, including the A-10 Thunderbolt II and SU-25 Frogfoot, have been specifically built for close air support, which in many cases include destroying tanks. Tourmaline is found in two main geological occurrences. Some infantry antitank weapons can also be configured to act as off-route mines. The meaning of the word "schorl" is a mystery, but it may be a Scandinavian word. Obviously a well placed off route mine will attempt to attack the rear or at worst the side of the tank, if at all possible. The word tourmaline is a corruption of the Sinhalese word turamali, meaning "stone attracting ash" (a reference to its pyroelectric properties). Some of the fusing systems are sophisticated enough to be able to discriminate between different classes of target and only attack specified classes of vehicles, e.g., ignore wheeled vehicles. It may account for 95% or more of all tourmaline in nature. 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. The most common variety of tourmaline is schorl, first described by Mathesius in 1524. The two common warheads for these mines are the ubiquitous HEAT and less commonly a platter charge. Some forms of tourmaline are dichroic, in that they appear to change color when viewed from different directions. When the tank passes they fire into the side of the tank. Crystals may be green at one end and pink at the other, or green on the outside and pink inside: this type is called watermelon tourmaline. are all likely spots. Bi-colored and multicoloured crystals are relatively common, reflecting variations of fluid chemistry during crystalisation. Choke points such as bridges, fords, gates, underpasses, etc. Rarely, it is colourless. These are mines that can be mounted on a vertical surface such as a wall, or tree, or mounted on a stand and are intended to be aimed at a road, track to other point a tank is likely to pass. Usually, iron-rich tourmalines are black to bluish-black to deep brown, while magnesium-rich varieties are brown to yellow, and lithium-rich tourmalines are practically any color: blue, green, red, yellow, pink etc. As well as the traditional bottom attack mine, the scatter mine, the artillery delivered mine, or air delivered mine, there are also a number of side attack or "off route" mines available. Tourmaline has a wide variety of colors. In addition with modern scatterable mines, and in particular artillery scatterable mines, it is actually possible to lay a mine field around a moving tank formation. At the time it was not realised that schorl and tourmaline were the same mineral. Mines have the advantage of attacking the thinnest armour of the tank and can be well concealed. Brightly coloured Sri Lankan gem tourmalines were brought to Europe in great quantities by the Dutch East India Company to satisfy demand as curios and gems. The tank is still vulnerable to mines. Tourmaline's unusual electrical properties made it famous in the early 18th century. In addition even the light cannon of the helicopter gunship can be effective as they can attack the thin top armour of the tank. Due to this effect, tourmaline crystals in collections may attract unsightly coatings of dust when displayed under hot spotlights. In addition most helicopter launched ATGWs have sufficient range that they can under the right conditions fire from ranges where the tank itself can not easily retaliate with its own weapons (though it is believed that some countries are developing anti-helicopter weapons that can be fired from a main gun and some tank gunnery systems are probably capable of hitting a hovering or slow moving helicopter at considerable range). Tourmaline crystals when warmed become positively charged at one end and negatively charged at the other. The helicopter can typically fire from behind cover, using its greater mobility to attack from an unexpected quarter. All hemimorphic crystals are piezoelectric, and are often pyroelectric as well. The single biggest threat to the tank today is the antitank helicopter armed with ATGWs (Anti-Tank Guided Weapons) or cannon. The deposit was discovered in the 1970s, but is now exhausted. laser designator) guidance for attacking tanks. An exception was the fine dravite tourmalines of Yinnietharra, in western Australia. 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. Tourmaline is rarely perfectly euhedral. All of the above bar the CLGP can be fired from medium (152/155-mm) artillery, both tube and rocket. Prisms faces often have heavy vertical striations that produce a rounded triangular effect. When a tank is identified a rocket is fired to direct the projectile at the tank. Tourmaline is distinguished by its three-sided prisms; no other common mineral has three sides. In order to allow the munitions time to use its sensor the munitions will often be deployed under a parachute. Small slender prismatic crystals are common in a fine-grained granite called aplite, often forming radial daisy-like patterns. The munitions contain some circuitry to identify tanks, such as IR or millimetre radar. Interestingly, the style of termination at the ends of crystals is asymmetrical, called hemimorphism. Once again the shell explodes above the tank position and dispenses a (usually smaller) number of submunitions. Tourmaline belongs to the trigonal crystal system and occurs as long, slender to thick prismatic and columnar crystals that are usually triangular in cross-section. More sophisticated are submunitions with a homing capability. It is a complex silicate of aluminium and boron, but because of isomorphous replacement (solid solution), its composition varies widely with sodium, calcium, iron, magnesium, lithium and other elements entering into the structure. A six-gun battery might be able to fire several hundred submunitions into an area in a minute or two. The tourmaline mineral group is chemically one of the most complicated groups of silicate minerals. A variation on this theme is replacing the top attack munitions with small antitank mines, which probably won't penetrate the armour but will blow off a track, leaving the tank vulnerable for destruction by other means. Mineral galleries Accessed 9/12/2005. If they do hit it will likely cause damage, despite their small size, since they are attacking the thin top armour. Mindat tourmaline group Accessed 9/12/2005. At its simplest the shell bursts in the air and a number of shaped charged (HEAT) or HEDP (High Explosive Dual Purpose) bomblets or grenades rain down, with luck hitting the tank. Tourmaline classification Accessed 9/12/2005. In addition to achieving a direct hit with guided projectiles, guided and unguided scatter munitions and submunitions have been developed: a single artillery shell containing a number of smaller munitions designed to attack a tank. Colorless - achroite (from the Greek for "colorless"). In addition some of these CLGP's such as the Copperhead have HEAT warheads instead of common HE. Green - verdelite or Brazilian emerald. These include laser guided projectiles, such as the US Copperhead CLGP (Cannon Launched Guided Projectile) which virtually guarantees a direct hit on the thin top armour. Light blue - Brazilian sapphire. In the last thirty years however, a variety of artillery projectiles have been developed with attacking tanks in mind. Dark blue - indicolite (from indigo). Even though a shell may not penetrate a tank's armour, it can still disable it through dynamic shock, internal armor shattering, or simply overturning the tank. Rose or pink - rubellite (from ruby). Traditionally, conventional artillery has not been very effective against tanks as the tank's armour could withstand any artillery round except a direct hit. Elbaite subgroup: named after the island of Elba, Italy
In addition in built up areas the tank is very vulnerable to attack from above—the roof and floor of the tank being traditionally the thinnest and weakest armoured surfaces. Black - schorl. Tanks are also vulnerable to hand placed antitank mines. Schorl subgroup:
Once an infantry man is close to a tank he cannot be targeted by its main weaponry unless the crew expose themselves to attack him, as the main gun and coaxial machine gun can not depress sufficiently to engage the close-in infantry man. However, the tank is a fearsome war machine; it takes confidence, discipline and training to carry this out. In theory, it is easy for an infantry man to lie prone, wait behind a tree or other handy cover or inside a building and to quickly dash out as a tank passes. If the crew commander is not closed down, that is, has exposed his head and perhaps upper body for the better view it affords him, then he can of course be shot. For veteran troops, it is relatively easy for an infantry man to get close to a tank, especially if it is fully closed down (that is, the commander is fully inside the turret) as tanks have very poor visibility close in and especially to the sides and rear, unless the turret is pointing in that direction. This is why modern tactics insist on tanks being closely supported by friendly infantry. This can give enemy infantry the initiative, allowing them to spot, track and evade tanks until an opportunity presents itself for a stealthy counter-attack. The armour and mobility of tanks, while usually notable assets, also makes them large and noisy. The tank is still vulnerable to infantry, especially in close country or built up areas. In fact it is the tank's superiority which has focused so much effort on improving antitank weapons. Whilst being a tremendously powerful weapon and the undoubted king of the land battlefield, the tank is not invulnerable. See also:. In addition to easing the reporting burden, these systems also allow for orders to be given complete with graphics and overlays, via the network. These integrate known information on enemy targets and friendly units to greatly improve the tank commander's situational awareness. tanks are fitted with digital computers which are connected into battlefield networks. U.S. A recent development in AFV equipment is the increased integration of fire control, the laser range-finder, GPS data, and digital communications. More advanced systems allow the commander to take control of the turret and fire the main armament in an emergency. 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. Since the 1960s, a tank's commander has had progressively more sophisticated equipment for target acquisition. 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. Most armoured forces operate with the crew commander, and possibly other crew members, "hatches up", for best possible situational awareness. Communications on a busy network are subject to a set of formalised language rules called radio voice procedure. Company or battalion commanders' tanks usually have an additional radio. 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. From the 1930s to the '50s, most nations' armoured forces became equipped with radios, but visual signals are still used to reduce radio chatter. Signal flares, smoke, movement, and weapons fire are all used by experienced crews to co-ordinate their tactics. In World War One, situation reports were sent back to headquarters by releasing carrier pigeons through vision slits. 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. Some tanks have even been equipped with an external intercom on the rear, to allow co-operating infantry to talk to the crew. Most modern AFVs are equipped with an intercom, allowing all crew members to talk to each other, and to operate the radio equipment. 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. In some early tanks, the crew commander's task was severely hampered by having to load or fire the main armament, or both. Every action of a tank's crew, movement and fire, is ordered by its commander. Armoured bulkheads, engine noise, intervening terrain, dust, and smoke, and the need to operate "hatches down" (or "buttoned up") comprise severe detriments to communications. Because of the isolation of small units, individual vehicles, and even the crewmen of a tank, special arrangements have had to be made. Commanding and co-ordinating a tank organisation in the field has always been subject to particular problems. Although the KLA had little chance of destroying the tanks, their purpose was to get the tanks to move whereupon they could be more easily identified and destroyed by NATO air power. This changed in the final week of the conflict, when the Kosovo Liberation Army began to engage tanks. During the initial few weeks of the conflict NATO air sorties were rather ineffective in destroying Serbian tanks. Getting a tank to move proved to be important in the Kosovo conflict in 1999. Another factor in the Gulf War was that, even when camouflaged and not moving, Iraqi tanks at night would cool at a different rate from their surroundings, making thermal detection easier. One of the reasons for the one-sided fighting during the Gulf War was that tanks like M1 Abrams had almost four times the night-time infrared scanning range of T-72s used by the Iraqi army. A moving tank is thus relatively easy to spot by good land-based or aerial infrared scanners. The unusually compact mass of metal of the tank hull dissipates heat in a fashion which marks it off sharply from other objects in the countryside. The very large power output of modern tank engines (typically in excess of 750kW or 1,000hp) ensure that they produce a distinct thermal signature. The acoustic signature of a turbine engine is much greater: its high-pitched whine can be much more easily distinguished from other sounds, near or far. The acoustic and seismic signatures of multi-fuel engines are comparable. When moving, the vibrations are greater. When a tank stands still with engine running the land trembles around it. The deep rumble of even a single tank can be heard a great distance on a quiet day, and the sharp diesel smell can be carried far downwind. From the outside a diesel powered tank smells, sounds, and feels quite like a diesel locomotive. Tanks are powered by a diesel or turbine engine of a power comparable to a diesel locomotive. Some camouflage nets are manufactured from unevenly distributed mix of materials with differing thermal properties, which are designed to "randomise" or at least reduce the regularity of the thermal signature of a tank. This risk can be reduced somewhat by the use or thermal blankets which reduce the radiation of heat while the engine and tracks cool. Indeed even if the tank itself is hidden, for example behind a hill, it is still possible for a skilled operator to detect the tank from the column of warmer air above the tank. A recently stopped stationary tank has a considerable heat signature. The tank tracks across lands can be spotted from the air, and in the desert movement can stir up vast dust clouds several times the size of the tanks. In both cases, however, once a tank starts its engine or begins to move it can be detected much more easily due to the heat and noise generated by its engine. By contrast, in the open it is very hard to hide a tank. Stationary tanks can be well camouflaged in woodland and forested areas where there is natural cover, making detection and attack from the air more difficult. Like most modern diesel engines used in tanks, gas turbines are usually multi-fuel engines. Piston engines also need well-maintained filters, but they are more resilient if the filter does fail. An improperly fitted filter, or a single bullet or piece of shrapnel can render the filter useless, potentially damaging the engine. 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. In practice, however, those parts experience a higher wear due to their higher working speeds. 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. The M1A2 was nicknamed Whispering Death for its quiet operation.[1]. On the other hand the acoustic signature of a tank with a muffled gas turbine can be quieter than a piston engine–powered one. 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. 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. T-80 tanks are commonly seen with large external fuel tanks to extend their range. Newer models of the M1 have a small secondary turbine engine as an APU to power the tank's systems while stationary, saving fuel by reducing the need to idle the main turbine. However they are much less fuel efficient, especially at low RPMs, requiring larger fuel tanks to achieve the same combat range. 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). M1 Abrams. 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. Modern tank engines are in some cases multi-fuel engines, which can operate on diesel, petrol or similar fuels. 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. 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. All modern non-turbine tanks use a diesel engine because diesel fuel is less flammable and more economical than petrol. The weight and type of power-plant (influenced by its transmission and drive train) largely determines how fast and mobile the tank is, but the terrain effectively limits the maximum speed of all tanks through the stress it puts on the suspension and the crew. Starting in the late 1970s, turbine engines began to appear. As the Cold War started, tanks had almost all switched over to using diesel, improved multi-fuel versions of which are still common. In the Second World War there was a mix of power-plant types used; a lot of tank engines were adapted aircraft engines. Tanks fielded in WWI mostly used petrol (gasoline) engines as power-plants, unlike the American Holt Gas-Electric tank which was powered by a petrol (gasoline) engine and an electric engine. The tank's power-plant supplies power for moving the tank and for other tank systems, such as rotating the turret or electrical power for a radio. Those that did make it ashore, however, provided essential fire support in the first critical hours, getting off the beaches. A number of these DDs sank due to rough weather in the Channel (having been launched too far out). The Sherman DD could not fire when afloat as the buoyancy screen was higher than the gun. This was referred to as the Sherman DD (Duplex Drive) and was used on D-Day to provide close fire support on the beaches during the initial landings. It was propelled by propellers driven by the main engine. In World War II the M4 Medium (Sherman) tank was made amphibious with the addition of a rubberised canvas screen to provide additional buoyancy. Often a fold down trim vane is erected to stop water washing over the bow of the tank and thus reducing the risk of the vehicle being swamped via the driver's hatch. Some light tanks such as the PT-76 are amphibious, typically being propelled in the water by hydrojets or by their tracks. However if properly planned and executed this type of operation adds considerable scope for surprise and flexibility in water crossing operations. This has influenced tactics in those countries where the psychological health of the crews or their capacity for rebellion is taken into account. Tank crews usually have a negative reaction towards deep fording. This type of fording requires careful preparation of the tank and the ingress and egress sites on the banks of the water obstacle. Russian snorkels are also fixed in length, providing only a couple of metres of depth over the turret height. 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. The height of the tube is limited to around three meters. This tube is then fitted to the crew commander's hatch and provides air and a possible escape route for the crew. The Leopard snorkel is in fact a series of rings which can be stacked to create a long tube. 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. However, with preparation some tanks are able to ford considerably deeper waters. The typical fording depth for MBTs is 90 to 120 cm. 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. For most tanks water operations are limited to fording. 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. Some tank-like vehicles use wheels instead of tracks in order to increase road speed and decrease maintenance needs. Using sea and ground transportation is slow, making tanks problematic for rapid reaction forces. Tanks, especially main battle tanks, are extremely heavy, making it very difficult to airlift them. Another mobility issue is getting the tank to the theatre of operations. 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. Frequent halts must be planned for preventive maintenance and verifications in order to avoid breakdowns during combat. 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. 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. 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. 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. 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). 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. On the road the fastest tank design is not much slower than the average wheeled fighting vehicle design. On paper, or during any test drive of a few hours, a single tank offers better off-road performance than any wheeled fighting vehicle. The logistics of getting from point A to point B are not as simple as they appear. The road speed may be up to 70 km/h. In "normal" terrain, a tank can be expected to travel at about 30 to 50 km/h. The types of terrain that do pose a problem are usually extremely soft ground such as swamps, or rocky terrain scattered with large boulders. 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. A main battle tank is designed to be very mobile and able to tackle most types of terrain. The third is its ability to be transported from one theatre of operation to other, dependent on its weight, air portability and so on. The second is the ability of the tank to be readily transported within a theatre of operation. 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. Mobility of a tank is categorised as Battlefield Mobility, Tactical Mobility, or Strategic Mobility. There are essentially two main aspects of mobility to consider, the tank's basic mobility such as its speed across terrain and ability to climb obstacles, and its overall battlefield mobility such as range, what bridges it can cross, and what transport vehicles can move it. Improvements in onboard optical systems are ongoing, in order to overcome this problem. Thus, when a tank advances in hostile territory with hatches closed, the commander and the crew might be personally safer, but the tank as a whole is more at risk given the extremely reduced vision. Tank periscopes and other viewing devices give a sharply inferior field of vision and sense of the countryside, despite constant advances in optics and electronics. In this rather high position the commander can see around the vehicle with no restrictions, and has the greatest chance of spotting enemy antitank operations or natural and unnatural obstacles which might immobilise or slow down the tank. Paradoxically, a tank is usually in its safest state when the commander is in a personally unsafe position, riding in the open, head out of the turret, with no personal protection save his helmet and a flak jacket. 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. An APS uses radar or other sensing technology to automatically react to incoming projectiles. Active protection systems go one step further than reactive armour. Reactive armour is attached to the outside of an MBT in small, replaceable bricks. 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 focussed explosive force of a shaped charge warhead. Passive countermeasures, like the Russian Shtora system, attempt to jam the guidance systems of incoming guided missiles. 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. 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. 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. Some tanks also have smoke generators which can generate smoke continuously, rather than the instantaneous, but short duration of smoke grenades. 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. 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). There have been proposals to equip other tanks with dual-purpose smoke/fragmentation grenade launchers that can be reloaded from the interior. 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. 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. 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 antitank missiles which require the operator to keep the tank in sight for a relatively long period of time. Modern smoke grenades work in the infrared as well as visible spectrum of light. 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. 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 Israeli Merkava tank takes the design of protection systems to an extreme, using the engine and fuel tanks as secondary armour (back-up armour). A form of Chobham armour is encased in depleted uranium on the very well-protected M1A1 Abrams MBT. One of the best types of passive armour is the British-developed Chobham armour, which is comprised of spaced ceramic blocks contained by a resin-fabric matrix between layers of conventional armour. Since the 1970s, some tanks have been protected by more complex composite armour, a sandwich of various alloys and ceramics. As a defence, some vehicles have a layer of anti-spall material lining their insides. This may kill the crew without penetrating the armour, still neutralizing the tank. Some antitank ammunition (HESH or HEP) uses flexible explosive material, which squashes against a vehicle's armour, and causes dangerous spalling of material inside the tank when the charge explodes. Thin plates of spaced armour, steel mesh "RPG screens", or rubber skirts, were found to cause HEAT rounds to detonate too far from the main armour, greatly reducing their penetrating power. These weapons carry a warhead with a shaped charge, which focuses the force of an explosion into a narrow penetrating stream. High explosive antitank weapons (HEAT), such as the bazooka, were a new threat in the Second World War. Many tracked military vehicles have side skirts, protecting the suspension. Even light infantry antitank weapons can immobilise a tank by damaging its suspension or track. German tank crews were said to be horrified to find that shots fired at the angled plates of T-34s would sometimes simply ricochet. Angling armour plates greatly increases their effectiveness against projectiles, by increasing the effective perpendicular thickness of the armour, and by increasing the chance of deflection. The most famous and successful example of this approach at the time was the T-34. Before the Second World War, several tank designers tried sloping the armour on experimental tanks. Even a simple Molotov cocktail on the engine deck, however, may disable or destroy most tanks. Aircraft cannon firing armour-piercing ammunition, such as the Hurribomber's 40mm or Stuka's 37mm, could be effective, also. During WW2, aircraft rockets earned a formidable reputation, especially in France after the Normandy landings (Operation Neptune); post-war analysis revealed many reported kills were near-misses. Today, tanks are vulnerable to specialised top-attack missile weapons and air attack. World War II American M4 Medium tank crews found the German Tigers to be practically invulnerable from the front, and were forced to employ flank attacks. The sides have less armour and the rear, belly and roof are least protected. The thickest and best-sloped armour is on the glacis plate and the turret front. Most armoured vehicles are best-protected at the front, and their crews always try to keep them pointed toward the likeliest direction of the enemy. The relative effectiveness of armour is expressed by comparison to rolled homogeneous armour. Most armoured fighting vehicles are manufactured of hardened steel plate, or in some cases aluminium. The amount of armour needed to protect against all conceivable threats from all angles would be far too heavy to be practical, so when designing an MBT much effort goes into finding the right balance between protection and weight. Most modern MBTs do offer near complete protection from artillery fragmentation and lighter antitank weapons such as rocket propelled grenades. Tanks are especially vulnerable to airborne threats. Tanks are also vulnerable to antitank guided missiles; antitank mines, larger bombs, and direct artillery hits, which can disable or destroy them. Commonly, protection against kinetic energy penetrators fired by other tanks is considered the most important. Its armour is designed to protect the vehicle and crew against a wide variety of threats. The main battle tank is the most heavily armoured vehicle in modern armies. 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. It also provides the tank with a useful weapon against slow, low-flying airborne targets like helicopters. 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. 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. For accuracy, shells are spun by gun-barrel rifling, or fin-stabilized (APFSDS, HEAT-FS, etc.). There are several types of ammunition designed to defeat armour, including High explosive squash head (HESH, also called high explosive plastic, HEP), High explosive antitank (HEAT), and kinetic energy penetrators (KEP, or armour-piercing discarding sabot APDS). As a result modern tanks can fire reasonably accurately while moving. Laser target designators may also be used to illuminate targets for guided munitions. Infrared, light-amplification, or thermal night vision equipment is also commonly incorporated. 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. Modern tanks have a variety of sophisticated systems to make them more accurate. 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. These were eventually replaced by Laser range-finders. Over time these sights were replaced with stereoscopic range-finders. Consequently, accuracy was limited at long range and concurrent movement and accurate shooting were largely impossible. Range to the target was estimated with the aid of a reticule (markings in the gun sight which are aligned to frame an object of known size, in this case a tank). Historically, tank weapons were aimed through simple optical sights and laid onto target by hand, with windage estimated or assisted with a reticule. These specialised weapons are now usually mounted on the chassis of an armoured personnel carrier. Some tanks have been adapted to specialised roles and have had unusual main armament such as flame-throwers. The 12.7-mm and 14.5-mm machine guns commonly carried on US and Russian tanks and the French Leclerc are also capable of destroying lightly-armoured vehicles at close range. Additionally, many tanks carry a roof-mounted or commander's cupola machine gun for close-in ground or limited air defence. However, a couple of French tanks such as the AMX-30 and AMX-40 carry a coaxial 20mm cannon that has a high rate of fire and can destroy lightly armoured vehicles. Typically, this is a small calibre (7.62 to 12.7 mm) machine gun mounted coaxially with the main gun. Usually, tanks carry other armament for short range defence against infantry or targets where the use of the main weapon would be ineffective or wasteful. This uneven cooling will cause the barrel to bend slightly and will affect long range accuracy. For instance, if it were to rain on a tank barrel the top would cool faster than the bottom, or a breeze on the left might cause the left side to cool faster then the right. Modern tank guns are generally fitted with thermal jackets which reduce the effect of uneven temperature on the barrel. The British Army and the Indian Army are now the only ones to field main battle tanks carrying rifled guns. Smoothbore (rather than rifled) guns are the dominant type of gun today. Some tanks can fire missiles through the gun. Tank guns have been able to fire many types of rounds, but their current use is commonly limited to kinetic energy (KE) penetrators and high explosive (HE) rounds. The current common sizes are 120mm calibre for Western tanks and 125mm for Eastern (Soviet and Chinese legacy) tanks. Although the calibre has not changed substantially since the end of the Second World War, modern guns are technologically superior. Tank guns are among the largest-calibre weapons in use on land, with only a few artillery pieces being larger. The main weapon of any modern tank is a single large gun. Examples of how different countries are influenced in their decisions are as follows:. 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. 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). Tank design is traditionally held to be a compromise between these three factors—it is not considered possible to maximise all three. 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. 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). Traditionally AFV mobility is measured by the following metrics:. "Strategic mobility" also includes the ability to travel at high speed on roads, and the ability to be carried on rail or truck transport. 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. 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. Firepower is the ability of a tank to defeat a target. The psychological effect on enemy soldiers of a tank's imposing battlefield presence is called shock action. The three traditional factors determining a tank's effectiveness are its firepower, mobility and protection. The advancing capabilities of tanks have been balanced by developments of other tanks and by continuous development of antitank weapons. They had been refined dramatically in response to continually changing threats and requirements, especially the threat of other tanks. 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. 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. In response to the threat of antitank guided missiles (ATGMs), the focus in development shifted away from armor thickness, to armor technology. The Centurion replaced all British medium cruiser tanks and 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. The first tank to 'get it all right' is generally considered to be the British Centurion tank, which (in its later versions) was able to take hits from the infamous German 88 mm gun, was armed with the deadly 105 mm Royal Ordnance L7 that was superior to anything in the field, and could reach 56 km/h due to its excellent 650-hp Rolls-Royce Meteor engine. However the Panther was not terribly well armoured, and could not really fight the heavy tanks on an equal basis. Many consider the turning point to be the Panther, which became the basis for almost every tank design after it. With only slightly more armour and somewhat larger engines to compensate, mediums were suddenly protected against almost all antitank weapons, even those mounted on heavy tanks, while at the same time having the mobility of a medium tank. A combination of better suspensions and greatly improved engines allowed late-war medium tanks to outperform early-war heavies. But the seeds for a true transformation had already been working their way into existing designs. However, the weight limitations of air transport made a practical light tank almost impossible to build, and this class gradually disappeared over time. use, airborne support as well. Light tanks were now limited to the reconnaissance role, and in U.S. After WWII, tank development proceeded largely as it had before, with improvements to both the medium and heavy classes. Even post-war, the M60 MBT had a smaller secondary turret for the commander's cupola. Most tanks retained at least one hull machine gun. Multiple-turreted tank designs like the Soviet T-35 were abandoned by World War II. It was appreciated that if the tank's gun was to be used to engage armoured targets then it needed to be as large and powerful as possible, making having one large gun with an all-round field of fire vital. Turrets, which were not previously a universal feature on tanks, were recognised as the way forward. 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. All major combatant powers also developed specialised self-propelled guns: artillery, tank destroyers, and assault guns (armoured vehicles carrying large-calibre guns). Tank chassis were adapted to a wide range of military jobs, including mine-clearing and combat engineering tasks. and German, some Soviet; British radios were common, but often of indifferent quality), vastly improving the direction of units. By this time most tanks were equipped with radios (all U.S. 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. Tanks with limited suspension travel subject their crew to massive shaking, making operation difficult, limiting speed, and making firing on the move practically impossible. Although this might not sound important, the quality of the suspension is the primary determinant of a tank's cross-country performance. Another major wartime advance was the introduction of radically improved suspension systems. 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. 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. However, they fared poorly in direct combat with British tanks and suffered severely against the Soviet T-34, which was superior in armour and weaponry. These fast-moving tanks and other armoured vehicles were a critical element of the Blitzkrieg. Germany for example, initially fielded lightly armoured and lightly armed tanks, such as the Panzer I, which had been intended for training use only. World War II saw a series of advances in tank design. Tank shape, previously guided purely by considerations of obstacle clearance, now became a trade-off, with a low profile desirable for stealth and stability. Vulnerability to tank and anti-tank fire led to a rapid up-armouring and up-gunning of almost all tank designs. 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. As the numbers of tanks on the battlefield increased, the chance of meetings grew to the point where all tanks had to be effective antitank vehicles as well. In practice these concepts proved dangerous. 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. 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. There was thought put into tank-against-tank combat, but the focus was on powerful antitank guns and similar weapons, including dedicated antitank vehicles. 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. 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. J.F.C. 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. 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. 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 antitank weapons. Finally, the heavy or infantry tanks were heavily armoured and generally very slow. The medium tanks, or cruiser tanks as they were known in the United Kingdom, were somewhat heavier and focussed on long-range high-speed travel. 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. Throughout this period several classes of tanks were common, most of this development taking place in the United Kingom. Patton, with tank experience during WWI, transferred from the Armored branch back to the Cavalry branch during this period. Even George S. The US did little development during this period because the Cavalry branch was senior to the Armored branch and managed to absorb most of the funding earmarked for tank development. 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 British designs were the most advanced, due largely to their interest in an armored force during the 1930s. With the tank concept now established, several nations designed and built tanks between the two world wars.
Germany fielded a small number of tanks, mainly captured, during World War I. Changing battlefield conditions and continued unreliability forced Allied tanks to continue evolving for the duration of the war, producing models such as the very long Mark V, which could navigate large obstacles, especially wide trenches, more easily than many modern armoured fighting vehicles (AFVs). German forces suffered from shock and lacked counter-weapons, though they did (accidentally) discover solid anti-tank shot, and the use of wider trenches to limit the British tanks' mobility. Deployment in small groups also lessened their tactical value and impact, which was still formidable during first encounters. Initial results with tanks were mixed, with problems in reliability (and impatient high command) causing considerable attrition in combat. The tank would eventually make trench warfare obsolete, and the thousands of tanks fielded during the war by French and British forces made a significant contribution. The first successful use of massed tanks in combat occurred at the Battle of Cambrai on November 20, 1917. The French developed the Schneider CA1 working from Holt caterpillar tractors, and first used it on April 16, 1917. Mortimore of the Royal Navy took a Mark I into action at Delville Wood during the Battle of the Somme on September 15, 1916. W. The first tank became operational when Captain H. The word tank was used to give the workers the impression they were constructing tracked water containers for the British army in Mesopotamia, and it was made official on December 24, 1915. Although initially termed landships by the Admiralty, the initial vehicles were colloquially referred to as water-carriers, later shortened to tanks, to preserve secrecy. The first successful prototype tank, nicknamed Little Willie, was tested for the British Army on September 6, 1915. Having already seen Rolls Royce armoured cars used by Royal Naval Air Service in 1914, and aware of schemes to create a tracked fighting vehicle, First Lord of the Admiralty Winston Churchill sponsored the Landships Committee to oversee development of this new weapon. . Although weapons systems and armour continue to be developed, many nations have been reconsidering the need for such heavy weaponry in a period characterised by unconventional warfare. Tanks and armour tactics have undergone many generations of evolution over nearly a century. 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. Tanks were first used in the First World War to break the deadlock of the trenches, and they evolved to gradually assume the role of cavalry on the battlefield. Tanks are also at a disadvantage in wooded terrain and urban environments, which cancel the advantages of the tank's long-range firepower and limit the crew's ability to detect potential threats. Without such support, tanks, despite their armour and mobility, are vulnerable to infantry, mines, artillery, and air power. While tanks are powerful fighting machines, they seldom operate alone, being organized into armoured units in combined arms forces. 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. 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. A tank is a tracked armoured fighting vehicle, designed primarily to engage enemy forces by the use of direct fire. C4ISTAR. Command, control, and communications (C3I). Military communications. To this end it is the only nation to have produced a main battle tank with the engine placed at the front and fuel surrounding the crew, to increase protection. Its primary concern is therefore crew survivability. Israel is a small, but relatively rich, nation, with limited manpower in a hostile political environment. Extensive maintenance is expected to be done in specialized depots. State-controlled design development proceeds in incremental changes. Soviet tanks are traditionally rugged, simple for production and maintenance ("quantity turns into quality"), as exemplified by the T-34. Enhanced reliability and lower maintenance requirements have also been important design goals. As a result, German tanks since have been designed to be very manoeuvrable, with a resulting decrease in protection. It lost more of its insufficiently-developed Tiger and Panther tanks due to mechanical breakdowns than enemy action. Germany's tanks were completely outmatched by the Soviet T-34 on the WWII Eastern front. As their tanks are expected to rarely be away from support and repair units, less emphasis is placed on the crew's ability to maintain the tank themselves or to continue fighting with it once damage has been sustained. The USA has a large army with sophisticated weaponry and a complex array of mobile support services. As limited resources may be available, the crew needs to be able to maintain their tanks in the field. Britain maintains a small, highly trained professional army, and so tank crew survivability is important. Britain has historically opted for better firepower and increased protection at the expense of some manoeuvrability. prepared fording depth (if different). unprepared fording depth. ground clearance. angle of side slope that can be negotiated. angle of slope that can be climbed. vertical step climbed. width of trench crossed. ground pressure. weight (bridge classification). off-road range. road range. off-road speed (a somewhat nebulous figure given the possible variation). road speed. power-to-weight ratio. engine torque. engine power. |