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Battle-tanks: makes a 3rd generation?

Battle-Tanks: Makes a 3rd Generation?

The Battle between Offence and Defence Goes on

In spite of anticipated defence cuts in East and West aimed at arriving at a balance in the number of battle-tanks on both sides, there will be continuing efforts towards achieving technical improvements.

What deeply influenced post-war developments was the sheer efficiency of shaped-charge munitions. Since armour-plating no longer afforded any protection the decisive factor in combat became mobility. As for the main criterion in combat, fire-power, it was further improved by an increase in first-round hit probability at long range. Effective combat ranges, which were a mere 100 metres in the First World War, rising to 500 or 800 metres in the Second, have now attained up to 2000 metres. We are of course talking of hit probability. However, this enhanced performance is not so much due to the progress in ordnance technology as to the improvement of the sighting and aiming systems. Electronic sensors and computers now make it become possible to measure and process a number of internal and external ballistic factors, while laser rangefinders determine distances with an accuracy of [+ or -] 10 metres. With present-day muzzle velocities, the only unpredictable factor is the effect of crosswinds along the trajectory of the shell. In terms of first-round hit probability the fire-power of modern battle tanks, whether by day or by night, on the move or stationary, has attained values that 15 years ago were theoretically unattainable.

Armour protection, which at first lagged behind for lack of the right materials, has seen a revival in the last 15 years. The whole picture has changed drastically, and a switch in combat parameter priorities has occurred. Armour protection has now cancelled out the previous tank generation's firepower and is now causing armies to revise their opinions about the combat effectiveness of their tank fleets. Combat effectiveness is now determined by spaced, multi-layer, composite, depleted uranium and reactive armour. Armour technology has indeed become of paramount importance.

In the same timespan as the criterion regarding protection shifted from mobility to reactive armour, the aim became to adapt the penetration power of guns and ammunition to the improved armour by improving their performances. As a first step came the increase in calibre from 90, then 105 to 120 or even 125 mm. Next there followed the development of the KE round into the sub-calibre APDS round. At present armour protection and penetration power are about even.

Improvement of the armour protection has made the sort of progress which would have been unimaginable 20 years ago. The penetration power of the 120 mm calibre has reached its limits. When this weapon was introduced no one could have foreseen that its potential for upgrading would so soon come to an end. A quantum jump in performance may be expected with the development of an electromagnetic gun but not before the year 2005: it could in any case not be retrofitted to existing tanks. In present circumstances only an enlargement of the calibre of the conventional weapon would pay off, provided it became standard throughout NATO.

The Leclerc

France chose to ignore the true significance of the East bloc's superiority in armour during the last 25 years and contented herself at first with the AMX-30, to which only minor improvements have been made. Quite apart from its inadequate ammunition (only shaped-charge) its other components are technically outdated. Subsequent developments, the AMX-32 and AMX-40, incorporated partial improvements, but these did not lead to their being put into service in France. The launching of an attempt at a joint France-German project, the Leopard 3, provided the basis, following its abandonment, for a new development which led in turn to the EPC (Engin Principal de Combat), then the Char Futur, and finally the Leclerc. The latter can be summed up in a few words as a Leopard 2 with a shortened engine compartment and a low-profile turret cum autoloader. The shorter engine compartment was made possible by the SACM hyperbar 1 100 kW (1 500 HP) diesel (like the MTU 880 series), economising nearly one metre and eliminating one road wheel. With a combat weight of nearly 53 tonnes the volume-to-weight ratio is about 0.96 t/[m.sup.3], which, as an indication of its degree of armour protection, is higher than the Leopard 2's or the Merkava's.

The second important feature of the Leclerc is its 120 mm gun. This purely French development's chamber is matched to the German model's (essential in case of war), but the barrel is approximately one metre longer. This means that with KE ammunition a muzzle velocity of just about 1 800 m/sec is attainable. The heavy NATO treble-thickness target is said to be able to be penetrated at up to 4 000 metres' range. This standard of comparison accords with what can be judged from the weapon's performance but says nothing about penetration power against the sort of modern types of armour already being used in East and West. According to an American estimate, even the fullest exploitation of the potential of the 120 mm gun will not render this calibre adequate in the years to come. Other types in East and West are fitted with 130 to 150 mm calibres. The introduction of the 120 mm Leclerc at this juncture would only be justified if its upgunning to a higher calibre were possible without posing any technical problems, i.e. if the turret's design already takes into account a heavier gun.

The adoption of a low-profile turret means a reduction in the frontal silhouette and hence increased survivability. But the mounting of an autoloader means doing away with the fourth crew member. There has been a lot of dispute about this. According to the Israelis, who have the widest and most recent experience, the fourth man is needed in combat, as reflected in their most recent development, the Merkava 3. Worth mentioning are improvements to the turret sub-system, even though these are only slight enhancements. For instance, the gun can be depressed to - 10 [degrees], which is one degree more than the M1 and the Leopard 2, and five more than the T64, T72 and T80. Seating the tank commander alongside the gun on the same level as the gunner gives him a better forward view but does not improve all-round visibility. The integration of a thermal viewer in the commander's periscope is an improvement over the Leopard 2 and M1. The two latter are only due to receive this sort of device during their next upgrading, thus giving the commander an independent day/night sight, which will be an advantage. The independent stabilized commander's sight with target handoff facility to the gunner (first introduced on the Leopard 2) has, with the fitting of a thermal imager to the aiming sight and observation system, been dispensed with for night operations. At night the commander is linked to the aiming sight by means of a <<light-pipe>>, in other words he can only see the target through the same <<window>> as the gunner. On the M1 this design applies to day sighting as well.

Equipping the Leclerc with an electrically powered turret and gun-laying system instead of an electro-hydraulic drive reduces weight and volume and is less costly, but above all eliminates the risk of fire, which is one of the reasons why the Israel Merkava 3 is all-electric.

The 24-round loader and rammer fitted in the turret rear allow for the selection of two types of munition. The two operations - selection and alignment of the rounds on the one hand and the loading of the gun on the other - are independent of one another, so that the first step can already be undertaken during the loading procedure, thus reducing the loading time. The above-mentioned system is also electrically powered. Manual loading is said to be possible but the time and effort required are not known.

Naturally, and as expected from a modern development, all the relevant electrical and electronic systems of the turret are linked to a digital data-bus. The cabling has thus been simplified and reduced.

What is quite new is the introduction of an integrated battlefield management system which displays to every member of the crew the status of his own systems and instruments, and shows the tank's position in relation to own troop dispositions as well as its geographical location. However, this presupposes that the accompanying units are similarly equipped.

The Leclerc's high cost has become difficult to squeeze into the French defence budget. In view of the similarly rising cost of the joint PAH-2 helicopter project, there is now talk of considerably reducing the numbers to be produced. Whereas the original aim was a total of 1 400 units, the number mentioned now is only 1 100, or even 825.

The Challenger 2

The British Chieftain was descended from the first of the post-World War II generation tanks like the Leopard 1, AMX-30, etc. The transition to the second generation - the Challenger (now called Challenger 1) was determined by the necessity to convert the Shir 1 and 2 tanks, which were under construction for the Shah of Iran, for British Army use. Owing to overthrow of the Shah the order was cancelled by the new government, with the result that the originally planned MBT 80 never saw the light of day. The most important feature of the Challenger 1 vehicle was the adoption for the first time of Chobham armour. The fire-control system together with the main armament (the rifled L 1105 gun) were not up to the performances of the NATO partners', with the result that a second-generation main battletank had to be hurriedly provided for the British army. Vickers obtained the contract to produce nine prototypes of the Challenger 2 by the end of 1990. Should these not measure up to army requirements, it will once more come down to a choice between the M1 and the Leopard 2.

The main features of the Vickers development will be a new high-pressure 120 mm gun which, if successful, is due to be fitted also to the Challenger 1. Chassis and engine will be borrowed from the Challenger 1, the transmission will be upgraded and hydropneumatic suspension is foreseen for the running gear. A considerable effort will be devoted to the turret system. An electric drive is planned for the turret and main armament, and the fire-control computer is to be an improved version of the M1's. The commander's periscope will be derived from the Leclere's and the gunner's sighting system will be a combination of SAGEM and Barr & Stroud developments. An overall weight of 62 tonnes is spoken of, which would reduce the original top speed of 67 to 55 km/h. This, however, is less serious than the reduced rate of acceleration which, when breaking cover, can be a decisive factor in battle.

The M1 Abrams

It would be inappropriate here to describe in detail the best known representatives of the second-generation main battle tank, the Leopard 2 and M1, since the aim is rather to illustrate current trends towards the enhancement of combat efficiency by existing or future modifications designed to adapt the tank to the changing threat.

The adoption by the USSR of the Israeli type of reactive armour, in particular on the T 80, made it necessary to improve the M1A1's armour protection by the use of depleted uranium for the turret and chassis plating. The consequent increase in weight was deemed acceptable, while the low level of radiation was considered harmless. At all events armour got a big boost, and according to an American publication (Armed Forces Journal International of February 1989) ought to be able to defeat the East bloc's 125 mm weapons as well as the Improved TOW II. It looks as though the US have made a big leap forwards. A further improvement is expected with the introduction of an independent commander's periscope with its own laser scope and integrated thermal imager. In addition, a [CO.sub.2] laser rangefinder and integrated battlefield management system are foreseen, although the same problem will arise here as with the Leclerc. This version, known as the M1 A2, is due to go into production as from 1992.

It is difficult to predict what further developments may take place in the USA, although experiments are under way with a Tank Test-Bed (TTB). This consists of an M1 chassis with an unmanned "mini-turret". The problems are similar to those encoutered with an externally mounted gun: the crew is safely seated inside the body of the vehicle but observation has to be conducted by means of optronic scanning devices and transmission systems. Experienced armour experts reject this type of system as surveillance is not adequate. However, no decision has yet been taken. What is known is that development is in progress on a bigger calibre gun necessitating an autoloader.

The Leopard 2

The West German Leopard 2 is being produced in seven batches. Apart from the usual structural modifications incorporated at the production stage, only two significant combat enhancement modifications have so far been made: the substitution of a digital computer for the analog computer and the adaptation of the armour to the latest techniques. Many upgrades are under discussion and the following could be given a priority. * Turret and chassis armouring * Commander's periscope with independent thermal imager * Initial assembly phase of battlefield management system * Fitting of a remote-controlled 7.62 mm machine-gun. * Reduction of IR signature * Minor modifications to various systems and devices.

Whether all the above upgrades can be carried out at one fell swoop has for budgetary reasons not yet been decided. There is a strong lobby within the Bundeswehr which would rather see an entirely new development instead of upgrading the Leopard 2. The total cost of the former is estimated at a minimum of DM 1.4 billion ($0.71 billion).

The Merkava Mk. 3

In accordance with the philosophy of the father of the Merkava project, General Tal, the Mk. I's armour protection was already extremely efficient. The latest improvement, in modular form, is that armour plates are bolted on the outside of the hull, thus permitting onsite replacement of the modules in the field and facilitating later upgrading. The mounting of a 120 mm gun was long overdue. Having failed to obtain a production licence, Israel went ahead and developed its own gun, including the ammunition. However, the chamber does allow it to fire German, French or US-produced ammunition. For greater safety the ammunition is now stowed in the rear of the hull in fire-proof baskets. The tank is fitted with a central NBC filtering system and an electromagnetic alert system to warn against approaching missiles. An internally manned 60 mm mortar serves for the engagement at close range of tank-killer units. The modern computerized fire-control system has been improved by the addition of a night vision system and primary stabilisation of the optics, complemented by an electrically powered aiming and tracking system.

The output of the Continental Motors engine has been increased to 1 200 HP and the running gear suspension adapted to this increase in power. In spite of the improved armour protection the weight has been reduced by one tonne to 62 tonnes.

Extremely close cooperation between user and industry, which incidentally produces all the tank parts except for the powerpack, resulted in a very short space of time in a highly efficient combat vehicle. The Merkawa's survivability has been considerably increased by its low silhouette, the removal of all flammable materials from the fighting compartment, the fire-proof ammunition stowage and its additional external armour plating. The alleged production cost of DM 2.3 million ($1.17 million) appears fairly implausible compared to other Western tanks.

The C-1 Ariete

Following its successful licence manufacture of the Leopard 1, Italy decided to embark on its own developments, not least so as to gain a foothold in the world defence market. The first of these, the OF 40, followed the same design as the Leopard 1, the only difference being that the strength of the armour was different in various places. The fire-control system was adapted to customer requirements, and for the first batch ordered by the United Arab Emirates corresponded to the technology of the seventies, a fact confirmed in competitive trials carried out in Saudi Arabia against newer developments.

Advances in armouring made the development of a new vehicle necessary. Apart from the arrival of composite armour, the new 120 mm gun was a determining factor. The powerpack consists of a new Iveco engine and ZF LSG 3000 transmission. Available optionally are the GIAT 120 mm gun, a Rheinmetall copy or the Italian OTO-Melara 120 mm. All other parts are said to be of Italian origin. The commander's periscope affords him an independent all-round view by day and by night, with an elevation of - 9 [degrees] to + 60 [degrees]. This permits aerial observation and in combination with the right ammunition gives an anti-helicopter capability. The aiming sight incorporates a laser rangefinder and is coupled to the main computer. The latter not only calculates the ballistic corrections but provides information about the system's status, its position, etc. Despite comprehensive trials the Ariete has still not been put into service.

The Osorio

After the cancellation of the delivery to Saudi Arabia of the Leopard 2, Engesa, taking the latter as its model, developed a very similar vehicle. Borrowing technology from a variety of countries, a young team without any experience of tanks married German, French and British components and sub-systems to its own concepts and, in contrast to the long drawn-out European development backed by comprehensive trialling in Saudi Arabia, brought off a very respectable technical achievement at the first attempt.

The chassis consists of an all-welded armour steel hull the front of which is in indigenous (or somehow acquired) composite armour. The lower hull sides slope inwards to support the torsion bar bearings. Steel skirts protect the tracks. The track suspension is of the Dunlop hydropneumatic type. The running gear is made of six rubber-tyred steel road wheels, idler at the front, idler sprocket at the rear and three track return rollers. The ZF final drive is similar to that of the Leopard 2. The idler suspension is fitted with a spindle take-up. The rear-mounted MWM engine develops 1 040 HP and is fitted with a paper cartridge and dust chamber air filter and with a flat radiator. The ZF LSG 3000 gearbox has an integrated retarder and a two fan drives. The Messier service brake acts on the final drive, the latter being linked to the gearbox by a splined shaft. Ground clearance is 460 mm at a specific ground pressure of 0.80 kg/[cm.sup.2]. Handled by the ZF transmission, the 1 040 HP of the improved MWM marine engine or, as alternative, of the future MTU engine, give the vehicle a high cross-country speed and a respectable acceleration of 0-30 km/h in 8 sec.

The all-welded turret is not of Engesa design but is produced by Vickers. It is similar to that of the Vickers Mk. 7, which is itself a joint development by Krauss-Maffei (Leopard 2 chassis) and Vickers (turret).

The armour steel turret is spaced on front and sides and comprises composite armour as well. The left half of the turret rear is used for ammunition stowage. The right-hand part houses the electronics and NBC installation. Turret traverse and weapon elevation are electric, while the smooth-bore 120 mm gun is a GIAT product, the barrel being longer and lighter than on the Leopard 2. Secondary armament consists of a coaxial 7.62 machinegun, a 7.62 mm anti-aircraft machinegun roof-mounted by the gun-layer's hatch and a bank of six Wegmann smoke dischargers on either side of the turret. The Marconi fire-control system is offered in two versions: an integrated one consisting of a day/night gunner's periscope with laser range-finder and of a day/night commander's scope to which is slaved the gun, or an automatically stabilized periscope and night vision system for commander and gunner with monitors. A radar/laser alert system coupled to the smoke dischargers completes the installation. For additional safety there is a Deugra fire-suppression system.

The STC (Type 88) Tank

This Japanese tank is of the third post-war generation and broadly follows Western designs. The weight of the 120 mm round is said to have dictated an autoloader because of the small stature of the Japanese soldier. This is open to doubt as "small" by no means signifies weak. No doubt its choice was due to the trend towards reducing the size of the crew and replacing Man by Machine. The 120 mm gun could be of local design or possibly the fruit of a licence agreement, but no firm decision has been made to date. The design of the autoloader in the turret rear is very akin to the Leclere's. Of interest are the side-by-side seating and parallel controls of commander and gunner in the turret. The fire-control system is from Mitsubishi Electric Co. Mitsubishi Heavy Industries for its part developed the 10-cylinder two-stroke diesel developing 1 100 kW. The suspension has been simplified by the use of torsion bars, as opposed to the hydropneumatic dampers of its predecessors. Protection consists of a combination of composite armour and ceramic plates. The increase in size due to this design is reflected in the weight (45-52 tonnes), although it does not attain that of Western types. The level of protection is not comparable either. The specific power-to-weight ratio of 22-24 kW/t permits high speeds. Because of the ban on the export of Japanese defense equipment, development costs and overheads can only be recouped on the vehicles sold in Japan, which increases the unit cost.

Arjun and Rokit

Both these Asian developments; from India and South Korea respectively, are in fact vehicles assembled out of a mixture of parts. Foreign components have been put together by local and American constructors and the completed systems produced by state enteprises in prototype form. In both cases the design follows Western practice. Their entry into service has been postponed several times and no firm performance data are available. At all events neither country can any longer be considered as a potential importer of main battle tanks, and after having overcome their teething problems both will in future figure as competitors on the international market.

The T 80

The Soviet T 80 is derived from the T64 series and not the T72. The most important features are an improved running gear and powerpack, enhanced armour protection and its ability to fire either standard 125 mm ammunition or guided missiles. In this respect the development comes closer to Western designs as regards complexity and cost, and is a departure from the simpler types of yore.

The effectiveness of its armour protection can only be guessed at, but the reactive armour packs visible on the outside convey a good impression. The choice of a turbine appears to have been a pis aller for want of an available diesel.

Western MBT developments are naturally determined by the capabilities of the most up-to-date potential adversary, in which armour protection seems to have reached the highest level. Added to which, the T 80's increased speed enhances its survivability. Concepts in East and West are in fact drawing together, with a resulting disproportionate escalation in cost. In the West this has led to the need to reduce numbers. This has only widened the gap between East and West since the former still maintains the same level of production.

A Final Word

The determining factors in the current East-West balance on the armour front are the M1, Leopard 2, the Leclerc and the T80. Only a treaty on mutually agreed ceilings accompanied by subsequent reductions to a level guaranteeing the inability to launch a surprise attack can preserve the military equilibrium. Owing to the introduction of the Leclerc and Challenger 2 in the near future, any intended synchronisation of armour development within the Western alliances in the next century is not to be expected. Due to the current inadequacy of their armour both France and Great Britain will have to do something soon to bring it up to the technological level of NATO. Should there be an East-West agreement on troop levels and a freeze on the numbers of tanks, perhaps even on technical developments, France and Great Britain will have to hurry. However, this means that as far as these two nations are concerned any synchronization of new tank developments at the beginning of the next century is out of the question. With the reduction in the number of production units (if the outcome of the Vienna talks is successful), and in spite of all attempts at cooperation, unit costs are of course bound to rise.

PHOTO : The General Dynamics M1A1's depleted uranium armour is said to be proof against the

PHOTO : Eastbloc 125 mm round and the ITOW II.

PHOTO : How much is too much? The FF29.5 million unit cost of the Leclerc is the price to pay if

PHOTO : the huge generation gap left behind the AMX-30 is to be bridged.

PHOTO : The long-awaited Leclerc is much needed in France where armoured forces still have to rely

PHOTO : on totally obsolete, antiquated post-war AMX-30-based tanks.

PHOTO : In addition to its new armour, the Abrams is now expected to receive an independent

PHOTO : commander's periscope with its own laserscope and integrated thermal imager.

PHOTO : Although the Leopard 2 is still in production, the number of planned upgrades is such that

PHOTO : a number of officials in the Bundeswehr favour an entirely new tank.

PHOTO : The Israeli Merkava departs from "conventional" designs in a number of ways, but it is the

PHOTO : direct result of relatively recent, real-life combat experience.

PHOTO : One of Italy's latest developments is the C-1 Ariete which features a composite armour.

PHOTO : The tank is available with a choice of three 120 mm main guns.

PHOTO : Ironically, Engesa could be said to have developed the first European tank: German design,

PHOTO : Vickers turret and Giat gun.
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Title Annotation:making improvements
Author:Krapke, Paul-Werner
Publication:Armada International
Date:Oct 1, 1989
Words:4363
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