Picard
Regular Member
- Joined
- Mar 8, 2013
- Messages
- 332
- Likes
- 757
Design and Development
The Main Battle Tank – Kampfpanzer 70
Development of Leopard 2 began in 1963., when the Federal Republic of Germany and the United States of America signed an agreement to develop a common tank, designated Main Battle Tank / Kampfpanzer 70. The MBT/KPz-70 was jointly developed by US General Motors and German Deutsche Entwicklungs-Gesselschaft mbH (DEG) consortium. DEG included companies such as MaK, Rheinstahl-Henschel, Lutherwerke and Kraus-Maffei. Major drive behind development was new intelligence which stated that the Soviets, who already had 115 mm armed T-62, were about to start building 125 mm armed T-64. In response to this, Rheinmetall started work on development of 120 mm L44 gun which provided the basis of the new tank.
The MBT/KPz-70 was intended to replace the M48A2G in German service. Tank was to have combat weight of around 50 tons, with hydro-pneumatic suspension and an automatic loader for its 152 mm XM150E5 main gun. This gun was to have the ability to fire the Shillelagh anti-tank missile as well as the conventional ammunition. Ammunition complement was 50 rounds, of which 26 were carried in the autoloader. The fire control system was to include a laser rangefinder and an infrared observation system. The tank was to be operated by a crew of three, all of whom – including the driver – were to be seated in the turret. The German version of tank was to have a 7,62 mm MG 3 machine gun coaxial to the main gun, and a 20 mm retractable automatic cannon in a cupola to the left of the turret roof, primarily for anti-aircraft purposes. US-built test chassis was ready in June 1966., and the German chassis in September 1966. First bilateral tests were carried out in October 1966., and showed the superiority of German hydro-pneumatic suspension system.
In February 1967., the 1500 PS liquid-cooled MTU MB 873 Ka 500 engine was ready, with its competitor being 1475 PS air-cooled Teledyne-Continental engine built in the US. In May 1967 construction drawings of the nationally developed components were exchanged, and in early 1968 it was agreed that only six prototypes would be built by each country instead of originally planned eight. By 1968., one MBT/KPz-70 cost twice as much as a Leopard 1, and by 1969. the project was already five times as expensive as the original estimate.
In 1969., three component trial vehicles, four Continental engine vehicles and three MTU engine vehicles were avilable for trials. It became obvious that the tank had become too heavy, and weight had to be reduced, but no agreement could be reached between the USA and Germany. Tank also faced issues regarding its use of caseless ammunition, auto-loaders and engine turbines. Biggest issue was the fact that the driver was seated in the turret and thus faced serious disorientation whenever the turret was turned. The programme finally ceased in January 1970 after 830 million DM had been spent and both nations went on to develop their own main battle tanks. USA continued with an austere version of MBT 70, designated as XM803, and subsequently developed the M1 Abrams. Germany used components developed for KPz-70 to develop a new main battle tank which would become Leopard 2.
The Keiler and the Eber
While Germany and United States were developing MBT/KPz-70 their agreement forbade any parallel national tank development programme. Still, when Leopard 1 was introduced into service in 1965, Porsche was awarded a contract to develop improved components to increase its combat effectiveness to the standard demanded of the MBT/KPz-70. This programme lasted until 1967, and became known as “Vergoldeter Leopard” (Gilded Leopard).
When German/American cooperation for development of MBT/KPz-70 started to break up in 1967., the German Ministry of Defense decided to increase the development programme for “Vergoldeter Leopard”, which later became known as “Keiler” (Wild Boar). Kraus-Maffei in Munich was chosen as the main contractor, with Porsche developing the chassis and Wegmann the turret. An agreement between MoD and Kraus-Maffei was finalized on 7 November 1968. Chassis development of the Experimentalentwicklung began in October 1968. Two prototypes (ET 01 and ET 02) were built in 1969 and 1970 for further evaluation, both powered by the 10-cylinder MB872 engine rated for 1250 PS.
In late 1969, with the end of the American-German tank development, the German Office for Defence Technology and Procurement (BWB) initiated a study to save the majority of the MBT/KPz-70 programme. This project, designated “Eber” (“Boar”), would combine parts of abandoned MBT/KPz-70 programme with components of the experimental tank, but it never reached the prototype status.
Leopard 2 prototypes 01 to 17
In early 1970, Helmut Schmidt, then German Defense Minister, recommended continued development of the “Vergoldeter Leopard”, with the adoption of the MTU engine developed for the MBT/KPz-70. Seven vehicles were ordered in addition to ten already planned prototypes, with Kraus-Maffei again chosen as the main contractor. In total, 16 prototype chassis (PT 1 to PT 11 and PT 13 to PT 17) and 17 turrets were built between 1972 and 1974. The prototypes were externally similar to Leopard 1A4 but had a wedge-shaped bow and an exhaust grille moved to the rear plate. The road wheels and tracks were taken from the MBT/KPz-70, and the return rollers from the Leopard 1. The prototypes varied in certain components. PT 11 and PT 17 had a hydro-pneumatic suspension invented for the MBT/KPz programme – only for it to become clear that the torsion bar suspension with integrated friction dampers was the better solution. PT 11 also had a remote-controlled 20 mm automatic cannon mounted on the turret roof. While PT 07, 09, 15 and 17 had a slightly modified engine, most prototypes had the 12 cylinder MTU MB-873 Ka-500 water-cooled multi-fuel four-stroke engine. This engine, together with its 20 kW generator, gearbox, air filters and cooling and braking systems, formed a compact power plant which could be easily replaced within 15 minutes.
The engine had two superchargers operated by the exhaust fumes. This gave it an output of 1500 PS at 2600 rpm. The Renk HSWL-354/3 gearbox had four speeds forward and reverse each. It also allowed a change of direction (left and right) in the two lower gears without reducing engine speed. Ten of the 17 turrets built were fitted with a 105 mm smoothbore gun, while the remaining seven had a 120 mm smoothbore gun, both guns designed and produced by Rheinmetall. These prototypes were known as Leopard 2 K (K = Kanone, that is, cannon or gun) as in 1970s the German Ministry of Defence and the BWB were still trying to save some major components of the MBT/KPz-70, particularly the 152 mm main gun and the Shillelagh missile. This led to initiation of the study Leopard 2 FK (FK = Flugkorper, missile), and military demands called for a common chassis to accept both turrets. The Leopard 2 FK programme was cancelled in 1971 for practical and economic reasons, with focus shifted to Leopard 2 K, which was later redesignated as simply Leopard 2.
Further military requirements demanded the weight of Leopard 2 to be in MLC 50 (Military Loading Class 50), and the fire control system in development was to be compatible with the turret of Leopard 1. The engineering tests of the prototypes were carried out at various localities between 1972 and 1974, and were followed by troop tests. Four tanks were sent to Shilo in Canada to carry out cold weather trials between 14 February and 19 March 1975 at temperatures down to -30 degrees. These were followed by high-temperature tests at up to +45 degrees in Yuma, Arizona, in April and May 1975. Weight of the prototypes was 1,5 tonnes above the required MLC 50, leading to a new lighter turret to be designed. This turret, designed by Wegmann, would become known as “Spitzmas-Turm” (Shrew-turret), and could be fitted with an EMES-13 optronic corelation rangefinder. This rangefinder, developed by Leitz and AEG-Telefunken, had a small base length of only 350 mm, allowing it to be installed into turret front. At the same time analysis of 1973 Yom Kippur war made it clear that increased armor protection would be a decisive factor in the future. For this reason decision was made to accept MLC 60 for Leopard 2, allowing increased armor. One of the turrets would also be modified with new multi-layer type of armor. This turret, turret number 14 mod. (T 14 mod.) was the first step towards Leopard 2 AV.
Leopard 2 AV
During 1973., negotiations began between USA and Germany to standardize certain components of both nations’ main battle tank for the eighties. This led to signing of the Memorandum of Understanding (MoU) on 11 December 1974., with an amendment signed in July 1976. One chassis, prototype PT 07, had been sold and delivered to the USA in February 1973., and was tested by the US Army at Aberdeen Proving Ground. Part of the MoU was a comparative test between a Leopard 2 prototype and the competing XM1 prototypes built by Chrysler and General Motors in the United States. It ws agreed to study how Leopard 2 could be modified with minimum change to meet US performance and cost characteristics, and Kraus-Maffei were given the requested performance characteristics of the XM1, including ballistic protection.
All these specifications were the result of the trials carried out by the US Army in the United States with Leopard 2 prototype PT 07. By this time however, 15 out of 17 prototypes had already been built with the remaining two nearing completion. Based on the altered German and the US military demands, Porsche, Kraus-Maffei and Wegmann designed and built Leopard 2AV (Austere Version). Leopard 2AV had new spaced armor on the hull and new turret based on experience with turret T 14 (mod). Modifications also included simplified fire control system, reviewed ammunition stowage, mine protection on the underside, replacement of the auxilliary generator with eight batteries, and the accomodation of the entire electronics and hydraulics in the turret rear. Two chassis – PT 19 and PT 20 – were built, as well as three turrets – T 19, T 20 and T 21. All were ready in 1976.
Leopard 2AV PT 19 mounted turret T 19 with a fire control system built by Hughes, which included the gunner’s sight and controls. For the tests in the USA PT 19 / T 19 was armed with the L7A3 105 mm main gun, as this same gun was also mounted on the XM1, though 120 mm gun could be quickly mounted if demanded. Turret T 20 had a German fire control system including the EMES 13 and was to be used for the German test programme. Turret T 21 was equipped like the turret T 20, but had the Rheinmetall 120 mm smooth bore gun installed from the beginning.
The Leopard 2 AV was originally intended to be tested at the same time as the XM1, but the German modification programme took longer than expected. The US Army thus proceeded with evaluation of prototypes built by Chrysler and General Motors, and requested full-scale development of the Chrysler XM1 design without waiting for the Leopard 2 AV. Nevertheless, at the end of August 1976, PT 19 and PT 20 with extra weight to simulate the turret, plus one hull and one turret for live firing tests, were transported to the United States by a C-5A Galaxy.
The comparative tests, known as Development Test (DT) and Operational Test (OT) were carried out at Aberdeen Proving Ground. They followed the same programme as XM1 prototypes and lasted until December 1976. US Army reported that the Leopard 2AV and XM1 were comparable in firepower and field mobility but that XM1 was superior in armor protection. Following the selection, it became obvious that the Leopard 2 prototype PT 07 had served as a source of technology in development of XM1 prototypes. It is also questionable how decision was made that XM1 was superior in armored protection. In reality, Leopard 2AV did not have any material in its armored cavities as the intention was for the US to fill in the cavities with whatever they felt was appropriate. As a result, Leopard 2AVs armored protection was not representative of an operational vehicle.
Following the comparative tests, PT 19 and PT 20 returned to Germany for further evaluation, but turret T 19 remained in the US until early 1977 and was adapted to the PT 07 chassis while main gun was changed from 105 mm to 120 mm which would be used in serial production. US Army also proposed to incorporate this gun into later batches of XM1. Following the live fire tests carried out by US personnel, turret T 19 was brought back to Germany and modified to same standard as turret T 21 before being mounted on the PT 19 chassis to be used in the evaluation programme for series production. PT 20, T 20 and T 14 (mod.) which was brought up to standard of the T 20 turret were also available for the evaluation. In September 1977. the German Ministry of Defense formally decided to go ahead with production of 1 800 Leopard 2s in five batches. Kraus-Maffei was chosen as the main contractor and systems manager with 55% production allocated to it, while Maschinenfabrik Kiel (MaK) was chosen as sub-contractor and would receive 45% of production. Wegmann was turret integrator and also received responsibility for coordinating the integration of EMES 15 fire control system which was developed by Hughes in cooperation with Krupp Atlas Elektronik. 120 mm smoothbore gun was supplied by Rheinmetall with the turret.
REST OF THE POST ON THE BLOG
