A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and battlefield mobility provided by tracks and a powerful engine; their main armament is often mounted within a turret. They are a mainstay of modern 20th and 21st century ground forces and a key part of combined arms combat.
Modern tanks are versatile mobile land weapons platforms whose main armament is a large-calibre tank gun mounted in a rotating gun turret, supplemented by machine guns or other ranged weapons such as anti-tank guided missiles or rocket launchers. They have heavy vehicle armour which provides protection for the crew, the vehicle's munition storage, fuel tank and propulsion systems. The use of tracks rather than wheels provides improved operational mobility which allows the tank to overcome rugged terrain and adverse conditions such as mud and ice/snow better than wheeled vehicles, and thus be more flexibly positioned at advantageous locations on the battlefield. These features enable the tank to perform in a variety of intense combat situations, simultaneously both offensively (with direct fire from their powerful main gun) and defensively (as fire support and defilade for friendly troops due to the near invulnerability to common infantry small arms and good resistance against heavier weapons, although anti-tank weapons used in 2022, some of them man-portable, have demonstrated the ability to destroy older generations of tanks with single shots), all while maintaining the mobility needed to exploit changing tactical situations. Fully integrating tanks into modern military forces spawned a new era of combat called armoured warfare.
Until the invention of the main battle tank, tanks were typically categorized either by weight class (ultralight, light, medium, heavy or super-heavy tanks) or doctrinal purpose (breakthrough, cavalry, infantry, cruiser, antinfantry, antitank, operational, qualitative reinforcement, combined arms, special operations, or reconnaissance tanks). Some are larger and more thickly armoured and with large guns, while others are smaller, lightly armoured, and equipped with a smaller calibre and lighter gun. These smaller tanks move over terrain with speed and agility and can perform a reconnaissance role in addition to engaging hostile targets. The smaller, faster tank would not normally engage in battle with a larger, heavily armoured tank, except during a surprise flanking manoeuvre.
Contents
Etymology
The word tank was first applied in a military context to British "landships" in 1915 to keep their nature secret before they entered service.
Origins
On 24 December 1915, a meeting took place at the Inter-Departmental Conference (including representatives of the Director of Naval Construction's Committee, the Admiralty, the Ministry of Munitions, and the War Office). Its purpose was to discuss the progress of the plans for what were described as "Caterpillar Machine Gun Destroyers or Land Cruisers." In his autobiography, Albert Gerald Stern (Secretary to the Landship Committee, later head of the Mechanical Warfare Supply Department) says that at that meeting:
Mr. (Thomas J.) Macnamara (M.P., and Parliamentary and Financial Secretary to the Admiralty) then suggested, for secrecy's sake, to change the title of the Landship Committee. Mr. d'Eyncourt agreed that it was very desirable to retain secrecy by all means, and proposed to refer to the vessel as a "Water Carrier". In Government offices, committees and departments are always known by their initials. For this reason I, as Secretary, considered the proposed title totally unsuitable. In our search for a synonymous term, we changed the word "Water Carrier" to "Tank," and became the "Tank Supply" or "T.S." Committee. That is how these weapons came to be called Tanks.
He incorrectly added, "and the name has now been adopted by all countries in the world."
Lieutenant-Colonel Ernest Swinton, who was secretary to the meeting, says that he was instructed to find a non-committal word when writing his report of the proceedings. In the evening he discussed it with a fellow officer, Lt-Col Walter Dally Jones, and they chose the word "tank". "That night, in the draft report of the conference, the word 'tank' was employed in its new sense for the first time." Swinton's Notes on the Employment of Tanks, in which he uses the word throughout, was published in January 1916.
In July 1918, Popular Science Monthly reported:
Because a fellow of the Royal Historical Society* has unintentionally misled the British public as to the origin of the famous "tanks", Sir William Tritton, who designed and built them, has published the real story of their name ... Since it was obviously inadvisable to herald "Little Willie's" reason for existence to the world he was known as the "Instructional Demonstration Unit." "Little Willie's" hull was called in the shop orders a "water carrier for Mesopotamia"; no one knew that the hull was intended to be mounted on a truck. Naturally, the water carrier began to be called a "tank". So the name came to be used by managers and foremen of the shop, until now it has a place in the army vocabulary and will probably be so known in history for all time.
International
The term "tank" is used throughout the English-speaking world, but other countries use different terminology. In France, the second country to use tanks in battle, the word tank or tanque was adopted initially, but was then, largely at the insistence of Colonel J.B.E. Estienne, rejected in favour of char d'assaut ("assault vehicle") or simply char ("vehicle"). During World War I, German sources tended to refer to British tanks as tanks and to their own as Kampfwagen. Later, tanks became referred to as "Panzer" (lit. 'armour'), a shortened form of the full term "Panzerkampfwagen", literally "armoured fighting vehicle". In Arabic, tanks are called Dabbāba. The same word is used in Turoyo (a western dialect of Aramaic), but Swadaya, an eastern dialect, uses rashupta instead. In Italian, a tank is a "carro armato" (lit. 'armed wagon'). Norway uses the term stridsvogn and Sweden the similar stridsvagn (lit. 'battle wagon', also used for chariots), whereas Denmark uses kampvogn (lit. 'fight wagon'). Finland uses panssarivaunu (armoured wagon), although tankki is also used colloquially. The Polish name czołg, derived from verb czołgać się ("to crawl"), is used, depicting the vehicle's movement and its speed. In Hungarian, the tank is called harckocsi (combat wagon), albeit tank is also common. In Japanese, the term sensha (戦車, lit. "battle vehicle") is taken from Chinese and used, and this term is likewise borrowed into Korean as jeoncha (전차/戰車); more recent Chinese literature uses the English-derived 坦克 tǎnkè (tank) as opposed to 戰車 zhànchē (battle vehicle) used in earlier days.
Development overview
The modern tank is the result of a century of development from the first primitive armoured vehicles, due to improvements in technology such as the internal combustion engine, which allowed the rapid movement of heavy armoured vehicles. As a result of these advances, tanks underwent tremendous shifts in capability in the years since their first appearance. Tanks in World War I were developed separately and simultaneously by Great Britain and France as a means to break the deadlock of trench warfare on the Western Front. The first British prototype, nicknamed Little Willie, was constructed at William Foster & Co. in Lincoln, England in 1915, with leading roles played by Major Walter Gordon Wilson who designed the gearbox and hull, and by William Tritton of William Foster and Co., who designed the track plates. This was a prototype of a new design that would become the British Army's Mark I tank, the first tank used in combat in September 1916 during the Battle of the Somme. The name "tank" was adopted by the British during the early stages of their development, as a security measure to conceal their purpose (see etymology). While the British and French built thousands of tanks in World War I, Germany was unconvinced of the tank's potential, and did not have enough resources, thus it built only twenty.
Tanks of the interwar period evolved into the much larger and more powerful designs of World War II. Important new concepts of armoured warfare were developed; the Soviet Union launched the first mass tank/air attack at Khalkhin Gol (Nomonhan) in August 1939 against the Japanese forces based there, and later developed the T-34, one of the predecessors of the main battle tank. Less than two weeks later, Germany began their large-scale armoured campaigns that would become known as blitzkrieg ("lightning war") – massed concentrations of tanks combined with motorised and mechanised infantry, artillery and air power designed to break through the enemy front and collapse enemy resistance.
The widespread introduction of high-explosive anti-tank warheads during the second half of World War II led to lightweight infantry-carried anti-tank weapons such as the Panzerfaust, which could destroy some types of tanks. Tanks in the Cold War were designed with these weapons in mind, and led to greatly improved armour types during the 1960s, especially composite armour. Improved engines, transmissions and suspensions allowed tanks of this period to grow larger. Aspects of gun technology changed significantly as well, with advances in shell design and aiming technology.
History
20th-century
The tank is the 20th-century realisation of an ancient concept: that of providing troops with mobile protection and firepower. The internal combustion engine, armour plate, and continuous track were key innovations leading to the invention of the modern tank.
During the 119 BC Battle of Mobei of the Han–Xiongnu War, the Han general Wei Qing led his army through a fatiguing expeditionary march across the Gobi desert only to find Yizhixie chanyu's main force waiting to encircle them on the other side. Using armoured heavy wagons known as "Wu Gang Wagon" (Chinese: 武剛車) in ring formations that provided Chinese archers, crossbowmen and infantry protection from the Xiongnu's powerful cavalry charges, and allowed Han troops to utilise their ranged weapons' advantages of precision. This forced a stalemate and allowed time for his troops to recover strength, before using the cover of a sandstorm to launch a counteroffensive which overran the nomads.
In the 15th century, Jan Žižka built armoured wagons known as 'Wagenburg' containing cannons and used them effectively in several battles during the Hussite-wars.
While some sources claim or imply that Leonardo da Vinci invented the tank, his late-15th-century drawings of armoured vehicles were never built and would have been impractical. These human-powered, wheeled vehicles with cannons would have been difficult for humans to move by themselves and use of animals inside the their hulls would have been problematic.
Continuous track, rather than conventional wheels, arose from attempts to improve the mobility of wheeled vehicles by spreading their weight, reducing ground pressure, and increasing their traction. Experiments can be traced back as far as the 17th century, and by the late nineteenth they existed in various recognisable and practical forms in several countries.
It is frequently claimed that Richard Lovell Edgeworth created a caterpillar track. It is true that in 1770 he patented a "machine, that should carry and lay down its own road", but this was Edgeworth's choice of words. His own account in his autobiography is of a horse-drawn wooden carriage on eight retractable legs, capable of lifting itself over high walls. The description bears no similarity to a caterpillar track. Armoured trains appeared in the mid-19th century, and various armoured steam and petrol-engined vehicles were also proposed.
21st century
The role of tank vs. tank combat is becoming diminished. Tanks work in concert with infantry in urban warfare by deploying them ahead of the platoon. When engaging enemy infantry, tanks can provide covering fire on the battlefield. Conversely, tanks can spearhead attacks when infantry are deployed in personnel carriers.
Tanks were used to spearhead the initial US invasion of Iraq in 2003. As of 2005, there were 1,100 M1 Abrams used by the United States Army in the course of the Iraq War, and they have proven to have an unexpectedly high level of vulnerability to roadside bombs. A relatively new type of remotely detonated mine, the explosively formed penetrator has been used with some success against American armoured vehicles (particularly the Bradley fighting vehicle). However, with upgrades to their armour in the rear, M1s have proven invaluable in fighting insurgents in urban combat, particularly at the Battle of Fallujah, where the US Marines brought in two extra brigades. Israeli Merkava tanks contain features that enable them to support infantry in low intensity conflicts (LIC) and counter-terrorism operations. Such features are the rear door and rear corridor, enabling the tank to carry infantry and embark safely; the IMI APAM-MP-T multi-purpose ammunition round, advanced C4IS systems and recently: TROPHY active protection system which protects the tank from shoulder-launched anti-tank weapons. During the Second Intifada further modifications were made, designated as "Merkava Mk. 3d Baz LIC".
In terms of firepower, the focus of 2010s-era R&D was increased detection capability such as thermal imagers, automated fire control systems for the guns and increased muzzle energy from the gun to improve range, accuracy and armour penetration. The most mature future gun technology is the electrothermal-chemical gun. The XM291 electrothermal-chemical tank gun has gone through successful multiple firing sequences on a modified American M8 Armored Gun System chassis. To improve tank protection, one field of research involves making the tank invisible to radar by adapting stealth technologies originally designed for aircraft. Improvements to camouflage or and attempts to render it invisible through active camouflage, which changes according to where the tank is located, are being pursued. Research is also ongoing in electromagnetic armour systems to disperse or deflect incoming shaped charges, as well as various forms of active protection systems to prevent incoming projectiles (RPGs, missiles, etc.) from striking the tank.
Mobility may be enhanced in future tanks by the use of diesel–electric or turbine–electric series hybrid drives—first used in a primitive, gasoline-engined form with Porsche's Elefant German tank destroyer of 1943—improving fuel efficiency while reducing the size and weight of the power plant. Furthermore, advances in gas turbine technology, including the use of advanced recuperators, have allowed for reduction in engine volume and mass to less than 1 m3 and 1 metric ton, respectively, while maintaining fuel efficiency similar to that of a diesel engine. In line with the new doctrine of network-centric warfare, the 2010s-era modern battle tank shows increasing sophistication in its electronics and communication systems. The future of tanks has been challenged by the proliferation of relatively inexpensive anti tank guided missiles and rockets during the Russo-Ukrainian War.
Design
The three traditional factors determining a tank's capability effectiveness are its firepower, protection, and mobility. Firepower is the ability of a tank's crew to identify, engage, and destroy enemy tanks and other targets using its large-calibre cannon. Protection is the degree to which the tank's armour, profile and camouflage enables the tank crew to evade detection, protect themselves from enemy fire, and retain vehicle functionality during and after combat. Mobility includes how well the tank can be transported by rail, sea, or air to the operational staging area; from the staging area by road or over terrain towards the enemy; and tactical movement by the tank over the battlefield during combat, including traversing of obstacles and rough terrain. The variations of tank designs have been determined by the way these three fundamental features are blended. For instance, in 1937, the French doctrine focused on firepower and protection more than mobility because tanks worked in intimate liaison with the infantry. There was also the case of the development of a heavy cruiser tank, which focused on armour and firepower to challenge Germany's Tiger and Panther tanks.
Classification
Tanks have been classified by weight, role, or other criteria, that has changed over time and place. Classification is determined by the prevailing theories of armoured warfare, which have been altered in turn by rapid advances in technology. No one classification system works across all periods or all nations; in particular, weight-based classification is inconsistent between countries and eras.
In World War I, the first tank designs focused on crossing wide trenches, requiring very long and large vehicles, such as the British Mark I; these became classified as heavy tanks. Tanks that fulfilled other combat roles were smaller, like the French Renault FT; these were classified as light tanks or tankettes. Many late-war and inter-war tank designs diverged from these according to new, though mostly untried, concepts for future tank roles and tactics. Tank classifications varied considerably according to each nation's own tank development, such as "cavalry tanks", "fast tanks", and "breakthrough tanks".
During World War II, many tank concepts were found unsatisfactory and discarded, mostly leaving the more multi-role tanks; these became easier to classify. Tank classes based on weight (and the corresponding transport and logistical needs) led to new definitions of heavy and light tank classes, with medium tanks covering the balance of those between. The British maintained cruiser tanks, focused on speed, and infantry tanks that traded speed for more armour. Tank destroyers are tanks or other armoured fighting vehicles specifically designed to defeat enemy tanks. Assault guns are armoured fighting vehicles that could combine the roles of infantry tanks and tank destroyers. Some tanks were converted to flame tanks, specialising on close-in attacks on enemy strongholds with flamethrowers. As the war went on, tanks tended to become larger and more powerful, shifting some tank classifications and leading to super-heavy tanks.
Experience and technology advances during the Cold War continued to consolidate tank roles. With the worldwide adoption of the modern main battle tank designs, which favour a modular universal design, most other classifications are dropped from modern terminology. All main battle tanks tend to have a good balance of speed, armour, and firepower, even while technology continues to improve all three. Being fairly large, main battle tanks can be complemented with light tanks, armoured personnel carriers, infantry fighting vehicles or similar relatively lighter armoured fighting vehicles, typically in the roles of armoured reconnaissance, amphibious or air assault operations, or against enemies lacking main battle tanks.
Offensive capabilities
The main weapon of modern tanks is typically a single, large-calibre cannon mounted in a fully traversing (rotating) gun turret. The typical modern tank gun is a smoothbore weapon capable of firing a variety of ammunition, including armour-piercing kinetic energy penetrators (KEP), also known as armour-piercing discarding sabot (APDS), and/or armour-piercing fin-stabilised discarding sabot (APFSDS) and high-explosive anti-tank (HEAT) shells, and/or high-explosive squash head (HESH) and/or anti-tank guided missiles (ATGM) to destroy armoured targets, as well as high-explosive (HE) shells for shooting at "soft" targets (unarmoured vehicles or troops) or fortifications. Canister shot may be used in close or urban combat situations where the risk of hitting friendly forces with shrapnel from HE rounds is unacceptably high.
A gyroscope is used to stabilise the main gun, allowing it to be effectively aimed and fired at the "short halt" or on the move. Modern tank guns are also commonly fitted with insulating thermal sleeves to reduce gun-barrel warping caused by uneven thermal expansion, bore evacuators to minimise gun firing fumes entering the crew compartment and sometimes muzzle brakes to minimise the effect of recoil on accuracy and rate of fire.
Traditionally, target detection relied on visual identification. This was accomplished from within the tank through telescopic periscopes; often, however, tank commanders would open up the hatch to view the outside surroundings, which improved situational awareness but incurred the penalty of vulnerability to sniper fire. Though several developments in target detection have taken place, these methods are still common practice. In the 2010s, more electronic target detection methods are available.
In some cases spotting rifles were used to confirm proper trajectory and range to a target. These spotting rifles were mounted co-axially to the main gun, and fired tracer ammunition ballistically matched to the gun itself. The gunner would track the movement of the tracer round in flight, and upon impact with a hard surface, it would give off a flash and a puff of smoke, after which the main gun was immediately fired. However this slow method has been mostly superseded by laser rangefinding equipment.
Modern tanks also use sophisticated light intensification and thermal imaging equipment to improve fighting capability at night, in poor weather and in smoke. The accuracy of modern tank guns is pushed to the mechanical limit by computerised fire-control systems. A fire-control system uses a laser rangefinder to determine the range to the target, a thermocouple, anemometer and wind vane to correct for weather effects and a muzzle referencing system to correct for gun-barrel temperature, warping and wear. Two sightings of a target with the range-finder enable calculation of the target movement vector. This information is combined with the known movement of the tank and the principles of ballistics to calculate the elevation and aim point that maximises the probability of hitting the target.
Protection and countermeasures
The measure of a tank's protection is the combination of its ability to avoid detection (due to having a low profile and through the use of camouflage), to avoid being hit by enemy fire, its resistance to the effects of enemy fire, and its capacity to sustain damage whilst still completing its objective, or at least protecting its crew. This is done by a variety of countermeasures, such as armour plating and reactive defences, as well as more complex ones such as heat-emissions reduction.
In common with most unit types, tanks are subject to additional hazards in dense wooded and urban combat environments which largely negate the advantages of the tank's long-range firepower and mobility, limit the crew's detection capabilities and can restrict turret traverse. Despite these disadvantages, tanks retain high survivability against previous-generation rocket-propelled grenades aimed at the most-armoured sections.
However, as effective and advanced as armour plating has become, tank survivability against newer-generation tandem-warhead anti-tank missiles is a concern for military planners. Tandem-warhead RPGs use two warheads to fool active protection systems; a first dummy warhead is fired first, to trigger the active defences, with the real warhead following it. For example, the RPG-29 from the 1980s is able to penetrate the frontal hull armour of the Challenger II and also managed to damage a M1 Abrams. As well, even tanks with advanced armour plating can have their tracks or gear cogs damaged by RPGs, which may render them immobile or hinder their mobility. Despite all of the advances in armour plating, a tank with its hatches open remains vulnerable to Molotov cocktail (gasoline bombs) and grenades. Even a "buttoned up" tank may have components which are vulnerable to Molotov cocktails, such as optics, extra gas cans and extra ammunition stored on the outside of the tank.
A tank avoids detection using the doctrine of countermeasures known as CCD: camouflage (looks the same as the surroundings), concealment (cannot be seen) and deception (looks like something else).
Camouflage can include disruptive painted shapes on the tank to break up the distinctive appearance and silhouette of a tank. Netting or actual branches from the surrounding landscape are also used. Prior to development of infrared technology, tanks were often given a coating of camouflage paint that, depending on environmental region or season, would allow it to blend in with the rest of its environment. A tank operating in wooded areas would typically get a green and brown paintjob; a tank in a winter environment would get white paint (often mixed with some darker colours); tanks in the desert often get khaki paintjobs.
Mobility
The mobility of a tank is described by its battlefield or tactical mobility, its operational mobility, and its strategic mobility.
Tactical mobility is the tank's ability to move through the battle area. This could include acceleration, braking, speed and rate of turn on varying terrain, and obstacle clearance: the tank's ability to travel over or through obstacles like walls, trenches, and water.
Operational mobility is the ability to move tanks hundreds of kilometres from a staging area to the battle area, for example, by using transport helicopters.
Strategic mobility is the ability of the tanks to be transported over long distances, usually by air or sea. For tanks to be transported efficiently by air, weight and volume must be kept within the transport aircraft's capabilities.
Tanks have high tactical mobility and can travel over most types of terrain due to their continuous tracks and advanced suspension. The tracks disperse the weight of the vehicle over a large area, resulting in less ground pressure. A tank can travel at approximately 40 kilometres per hour (25 mph) across flat terrain and up to 70 kilometres per hour (43 mph) on roads, but due to the mechanical strain this places on the vehicle and the logistical strain on fuel delivery and tank maintenance, these must be considered exceptional "burst" speeds.
Tanks are susceptible to mechanical failure of engine and transmission systems, particularly at maximum burst speeds. Consequently, wheeled tank transporters and rail transport are used wherever possible for non-combat tank transport. Tank mobility is very restricted compared to wheeled armoured fighting vehicles. Most operational mobility in blitzkrieg tank operations was conducted at the pedestrian pace of 5 kilometres per hour (3.1 mph), and that was only achieved on the roads of France.
Suspension and running gear
Tank agility is a function of the weight of the tank due to its inertia while manoeuvring and its ground pressure, the power output of the installed power plant and the tank transmission and track design. In addition, rough terrain effectively limits the tank's speed through the stress it puts on the suspension and the crew. A breakthrough in this area was achieved during World War II when improved suspension systems were developed that allowed better cross-country performance and limited firing on the move. Systems like the earlier Christie or later torsion-bar suspension developed by Ferdinand Porsche dramatically improved the tank's cross-country performance and overall mobility.
Engine
The tank's power plant supplies kinetic energy to move the tank, and electric power via a generator to components such as the turret rotation motors and the tank's electronic systems.
The tank power plant evolved from predominantly petrol and adapted large-displacement aeronautical or automotive engines to diesel engines. Japan was the first to begin transitioning to this engine type beginning with the Type 89B in 1934. The main advantage of diesel is their higher fuel economy, which allows for greater operating ranges. Diesel engines can also run on a variety of fuels, such as aviation kerosene and even gasoline. Advanced multi-fuel diesel engines have been adopted. Gas turbines are powerful per unit weight but fuel-hungry; they have been used in a few tanks, including the Soviet T-80 and American M1 Abrams.
Fording
In the absence of combat engineers, most tanks can only ford small rivers. The typical fording depth for MBTs is approximately 1 m (3.3 ft), being limited by the height of the engine air intake and driver's position. Modern tanks such as the Russian T-90 and the German Leopard 1 and Leopard 2 tanks can ford to a depth of 3 to 4 m (9.8 to 13.1 ft) when properly prepared and equipped with a snorkel to supply air for the crew and engine. Tank crews usually strongly dislike deep fording, but it adds considerable scope for surprise and tactical flexibility in water-crossing operations by opening new and unexpected avenues of attack.
Amphibious tanks are specially designed or adapted for water operations, such as by including snorkels and skirts, but they are rare in modern armies. Purpose-built amphibious assault vehicles or armoured personnel carriers are used, without tanks, in amphibious assaults. Advances such as the EFA mobile bridge and armoured vehicle-launched scissors bridges have also reduced the impediment to tank advance that rivers posed in World War II.
Crew
Most modern tanks most often have four crew members, or three if an auto-loader is installed. These are the:
Commander – The commander is responsible for commanding the tank, with all-round vision devices rather than the limited vision of the driver and gunner. He guides the gunner roughly onto target and guides the driver around turns and obstacles.
Gunner – The gunner is responsible for laying (aiming) the gun. It may be laying for direct fire, where the gun is aimed similarly to a rifle, or indirect fire, where firing data is calculated and applied to the sights. The term includes automated aiming using, for example, radar-derived target data and computer-controlled guns. Gun laying involves moving the axis of the bore of the barrel in two planes, horizontal and vertical. A gun is "traversed" (rotated in a horizontal plane) to align it with the target, and "elevated" (moved in the vertical plane) to range it to the target.
Loader – The loader loads the gun, with a round appropriate to the target (HEAT, smoke, etc.) as ordered by either the commander or the gunner. The loader is usually the lowest-ranked member of the crew. In tanks with auto-loaders this position is omitted.
Driver – The driver drives the tank, and also performs routine maintenance on the automotive features.
Operating a tank is a team effort. For example, the loader is assisted by the rest of the crew in stowing ammunition. The driver is assisted in maintaining the automotive features.
Historically, crews have varied from two to twelve members. First World War tanks carried the crew needed to man the multiple guns and machine guns, and up to four crewmen to drive the tank: the commander drove the tank and manned the brakes, steering via orders to his gears-men; a co-driver operated the gearbox and throttle; and two gears-men, one for each track, steered by setting their side to idle, allowing the track on the other side to slew the tank to one side. Pre-World War II French tanks were noted for having a two-man crew, in which the overworked commander had to load and fire the gun in addition to commanding the tank.
Engineering constraints
A noted author on the subject of tank design engineering, Richard Ogorkiewicz, outlined the following basic engineering sub-systems that are commonly incorporated into a tank's technological development:
Mobility (through chassis design)
Engines
Transmissions
Suspensions and running gear
Soil-vehicle mechanics
Guns and ammunition
Ballistics and mechanics of guns
Vision and sighting systems
Illuminating and night vision systems
Fire control systems for main and auxiliary weapons
Gun control systems
Guided weapons
Armour protection
Configuration
To the above can be added unit communication systems and electronic anti-tank countermeasures, crew ergonomic and survival systems (including flame suppression), and provision for technological upgrading.
Few tank designs have survived their entire service lives without some upgrading or modernisation, particularly during wartime, including some that have changed almost beyond recognition, such as the latest Israeli Magach versions.
The characteristics of a tank are determined by the performance criteria required for the tank. The obstacles that must be traversed affect the vehicle's front and rear profiles. The types of terrain specified to be traversed determine the maximum permissible track ground pressure.
Command, control, and communications
Commanding and coordinating tanks in the field has always been subject to particular problems, particularly in the area of communications, but in modern armies these problems have been partially alleviated by networked, integrated systems that enable communications and contribute to enhanced situational awareness.
20th century
Armoured bulkheads, engine noise, intervening terrain, dust and smoke, and the need to operate with hatches closed are severe detriments to communication and lead to a sense of isolation for small tank units, individual vehicles, and tank crew. Radios were not portable or robust enough to be mounted in a tank, although Morse code transmitters were installed in some Mark IVs at Cambrai as messaging vehicles. The mounting of a field telephone to the rear was not a practice. During World War I when these failed or were unavailable, situation reports were sent back to headquarters by some crews releasing carrier pigeons through loopholes or hatches and communications between vehicles was accomplished using hand signals, handheld semaphore flags which continued in use in the Red Army/Soviet Army through the Second and Cold wars, or by foot or horse-mounted messengers.
From the beginning, the German military stressed wireless communications, equipping their combat vehicles with radios, and drilled all units to rely on disciplined radio use as a basic element of tactics. This allowed them to respond to developing threats and opportunities during battles, giving the Germans a notable tactical advantage early in the war; even where Allied tanks initially had better firepower and armour, they generally lacked individual radios. By mid-war, Western Allied tanks adopted full use of radios, although Russian use of radios remained relatively limited.
On the modern battlefield an intercom mounted in the crew helmet provides internal communications and a link to the radio network, and on some tanks an external intercom on the rear of the tank provides communication with co-operating infantry. Radio networks employ radio voice procedure to minimize confusion and "chatter".
A recent development in AFV equipment and doctrine is integration of information from the fire control system, laser rangefinder, Global Positioning System and terrain information via hardened military specification electronics and a battlefield network to display information on enemy targets and friendly units on a monitor in the tank. The sensor data can be sourced from nearby tanks, planes, UAVs or, in the future infantry (such as the US Future Force Warrior project). This improves the tank commander's situational awareness and ability to navigate the battlefield and select and engage targets. In addition to easing the reporting burden by automatically logging all orders and actions, orders are sent via the network with text and graphical overlays. This is known as Network-centric warfare by the US, Network Enabled Capability (UK) or Digital Army Battle Management System צי"ד (Israel). Advanced battle tanks, including the K-2 Black Panther, have taken up the first major step forward in adopting a fully radar integrated Fire Control System which allows it to detect tanks from a further distance and identify it as a friend-or-foe as well as increasing the tank's accuracy as well as its capability to lock onto tanks.



