Tanks are vehicles that are designed for soldiers to fight from and they have armour for protection. Armoured cars were in use from 1914 and used by the Royal Navy in Belgium. The tank first saw action in 1916. The current designation for a 'tank' is MBT (Main Battle Tank) although there are others.

A Short History of the Use of Tanks

In 1915 the British were in trouble on the Western Front. The pre-war trained soldier was no more and the attrition rate of infantry in particular was too high. A committee was set up to look into ways to overcome the stalemate of the trenches by mechanical means and the project was top secret. The prototype was called Tank to disguise its true purpose. Workers were told these things were 'watercarriers for Mesopotamia' – hence tank. The official name was Landship. After a poor debut, they were used successfully to break the German Line on several occasions.

The next major development was Blitzkrieg ('lightning war') developed by the Germans and put to deadly effect in 1939 (Poland) and 1940 (NW Europe). This used tanks to break through enemy lines, cause havoc in rear areas and outflank major forces. Infantry accompanied tanks in Armoured Personnel Carriers (APCs), but the bulk of the infantry marched in their wake.

This method was also used in the attack on Russia (Operation Barbarossa) and only narrowly failed to reach its objective, Moscow, before winter put a stop to offensive action. The Allies successfully adapted Blitzkrieg and paid back the Germans in kind. It is the basis of all armoured warfare to this day. The Israelis showed their grasp of armoured warfare to their Arab neighbours three times (1956, 1967 and, after initial Arab victories, 1973). Operation Desert Storm also used similar techniques.

Limitations

Armoured warfare needs wide open spaces, but is not the best way of combating guerrilla forces as the US discovered in Vietnam and as the USSR discovered in Afghanistan. Nor is it useful against civil populations (Hungary 1956, Czechoslovakia 1968 and Tianamen Square 1989). In these cases it was found that, once closed down (hatches closed), lone tanks were relatively easy to approach. This allowed the use of Molotov Cocktails (home-made petrol bombs) or light anti-tank weapons (grenades, rockets, etc). However, tanks still maintain their domination of any scene provided they appear in large numbers and support each other.

Some Background on Design

The design of AFVs revolves around

• Protection
• Firepower
• Mobility

Different nations adopt different priorities, For example:

• British - Firepower, Protection, Mobility (Chieftain MBT)
• Israel – Protection, Firepower Mobility (Merkava MBT)
• USSR – Mobility, Firepower, Protection (T62 MBT)

These priorities change over the years so they cannot be taken as being typical of those countries today.

Firepower

This is usually taken as a gun (cannon) but can also include missiles. The 'standard' MBT gun is of 120 - 125mm calibre. Most are now smooth-bore to enable the firing of tube-launched missiles, but the British have stuck with a 120mm rifled gun. All have stabilisation – the ability to stay locked on to a target no matter what the vehicle does, electronic ranging by laser and thermal imaging sights. Most guarantee a first round hit at 1500 metres.

Ammunition used is APFSDS (Armour-Piercing, Fin Stabilised, Discarding Sabot) or sabot. This is either Tungsten steel (TS) or, controversially, Depleted Uranium (DU). This is a sub-calibre Kinetic Energy (KE) dart (no explosive). It is smaller than the barrel calibre and is held centrally in the barrel by a plastic case or sabot. On firing, the light weight produces a high velocity and the sabot is removed by air pressure after leaving the muzzle. It penetrates armour plate by hardness/density and high velocity generating heat and pressure. This melts the steel and produces a shower of molten metal, which can cause explosions in fuel and ammunition. It has a similar effect on the crew. In Desert Storm, one US M1A1 Abrams dispatched two T72s with one DU round. The longest range for a confirmed kill in Desert Storm was a Challenger 1 engaging a tank at 5.1km using a DU sabot round.

There is also HESH (High Explosive, Squash Head) in use by the British which flattens itself on the armour plate before exploding and 'blisters' the inside which sends shards throughout the tank, killing the crew. It has a longer range than the sabot round.

Protection

Protection is the physical protection from anti-tank ammunition by armour or the organisation of the layout of the vehicle. The whole concept of protection goes hand-in-hand with the development of armour-defeating ammunition.

The armour on the original tank was just bullet-proof, a protection against machine gun fire. The Germans quickly found out that a 13mm rifle could defeat it as well as conventional artillery. Armour meant armour plate steel which was defined by its thickness. Thick armour plate meant increased weight, which affected mobility. Small calibre, high velocity, solid projectiles worked well, but increasing thickness meant larger calibre, more powerful rounds until anti-tank guns resembled field artillery. The USSR developed the concept of sloped armour to increase the ricochet effect and the apparent thickness of the plate.

The Germans developed the shaped charge as an anti-tank weapon. This was a charge of high explosive with a conical indent in it. When ignited, it formed a narrow jet of super hot gases, which melted its way through the armour plate and showered the inside with molten metal. The answer here was spaced armour, which set the charge off before it could do any real damage to the amour plate. The Allies called these HEAT (High Explosive, Anti Tank) rounds.

Modern composite armour is a sandwich of ceramic plates and armour plate. The ceramic plate dissipates the effect of HEAT rounds and can have a similar effect on KE rounds, but to a far lesser degree. The main advantage of composite armour is its light weight.

Reactive armour is the Russian solution to HEAT ammunition. This is explosives attached to the outer hull which explode with the HEAT round and dissipate the jet. The effect on the crew is not recorded.

Most MBTs have the engine at the rear for more protection The Israeli Merkava is unique among modern MBTs in that the engine is at the front. This was primarily to protect the crew from head-on shots, which defeated many Israeli tanks in earlier actions.

Mobility

The Germans, once again showed that speed was a vital factor in Blitzkrieg warfare. The USSR copied this and expected its tanks to be as speedy as the German ones. As a comparison, in 1940, the Panzer III had a speed of 25mph, the British Cruiser Tanks (thin armour) had a speed of 25mph but the Infantry Tank (Matilda – thick armour) had a speed of 5mph. The USSR's Christie Tanks (BT) had a road speed of 50mph and a cross country speed of 30mph.

Modern tanks are powered by diesels (Challenger, T72) or gas turbine (M1A1, T80). All have automatic or semi-automatic transmission. All are designed for economy of fuel and to support a speed of 30mph. Diesel and turbine fuel are also less likely to catch fire.

Tracks are now rubber-bushed, which means that instead of a simple pin to join each link in the track, these pins are placed in a rubber bushing in each track link. This has the effect of reducing wear, lessening noise and making the track easier on the transmission. Most tracks now also have rubber blocks on each link to reduce noise, road damage and lengthen the life of the track.

The End?

Technology has improved the Tank out of all recognition in the past twenty years. It has also increased the cost. Chieftain (1975) cost around £1M, Challenger 2 is £4M ($6M). The M1A1 Abrams is $4.3M. MBTs are essential to modern defence, but the cost of development and procurement is spiraling out of control. Where it will end? Probably when there is no foreseeable use for MBTs.