The tests of the 1st generation group A prototype, (Porsche Model 734), began in January 1961. This prototype was a bit longer and heavier reaching 32.5 tons of weight. It had better protection but it had the same engine, the Daimler MB837 of 660 hp.During tests, problems with suspension and engine were detected, which forced modifications to improve its reliability and performance. However, the 1st generation group A prototype was considered superior and the construction of 26 vehicles was started to continue development.Tests of the 1st generation group B prototype were carried out in September 1961, and it soon became clear that it was a more advanced design. It was a bit lighter and smaller and mounted the same Daimler MB837 660 hp engine but a different gearbox than group A prototype.First generation group B prototype had an hydro-pneumatic suspension that combined shock absorbers with springs and could be raised and lowered by controlling the oil level in the cylinders. The transmission was also very advanced, but despite these advantages, this prototype did not go ahead. It was considered that its manufacture would be very complex producing delays in production.The development continued with the “2nd Generation prototypes” or “Prototype II A tanks”. The problems found in the previous tests were solved and the work was focused on converting the requirements into reality. These prototypes began to be known as Standarised Tank or Standard MBT.In these 2nd generation prototypes, modifications were included that greatly improved their mobility. New suspension and a new 10 cylinders and 830 hp diesel engine coupled to a new gearbox were installed. Definitively, It was also decided not to install the hydro-pneumatic suspension.The protection and the armament were improved in the Prototype II A. The armour thickness was increased, the fire control system was improved and the British 105mm L7A3 gun was installed. In addition, a basic coincidence rangefinder was installed to improve aiming.France left the project after differences with Germany in the main armament’s choice and the program’s completion deadline. France preferred to install its own 105mm gun instead the British model despite only having one type of tank-killing ammunition, instead of three types offered by the L7 gun.The L7 gun’s range of ammunition included three types of anti-tank rounds, such as the APDS (armor-piercing, discarding-sabot), HESH (high-explosive, squash-head) and the American HEAT (high-explosive, anti-tank).Twenty-six Prototype II A tanks were built, which were sent at the end of 1962 to the “Panzerlehrbataillon 93”. This is a special trials unit attached to the Münster Lager Panzertruppenschule, (school for armored troops in Münster), site in Heidekreis, Lower Saxony.While twenty-six Prototype II A tanks were tested in Münster, fifty tanks designated as “Pre-Series Production” or “0-Series” were requested. Here we see a tank that has installed a turret from the Proto II A type in a hull from the Pre-Series model.This kind of “hybrid tank”, usually emerged from the long stages of development.Original requirements demanded a weight not exceeding 30 tons and a 105mm gun capable of penetrating 150mm Rolled Homogenous Armor (RHA) at 2,500 meters combat range. In addition, immunity against 20mm rounds, a power-to-weight ratio of 30 hp per tonne, a road speed of 65km/h, an off road speed of 40 km/h. Finally, a high range and NBC protection were essential requests. It can be said that all were achieved with the Pre-Series vehicles, (like the one in the picture), except the weight, which was an unreal pretension for a tank of these characteristics.These Pre-Series tanks had a new cast turret that was completed with a new optical range-finding system and new triangulation optics that significantly improved the long range gunnery. In addition, the engine compartment had to be modified to give more room for the engine.Pre-Series tanks incorporated many improved components that did not carry the previous prototypes. They were practically the Leopard tanks that would later leave the assembly lines. In July 1963, a first order of 1,500 Leopard tanks was made by the German Defense Ministry. These tanks must be delivered in the period 1965-70.Another highlight of Leopard was the possibility of fording rivers up to 5 meters deep with adequate equipment or up to 1.20 meters without preparation. The Pre-Series tanks were able to demonstrate these capabilities in summer 1964. Then, they crossed the Rhine River and were lent to different NATO countries so they could evaluate their capacities for future acquisitions.The successful combination of lightweight, great acceleration and excellent off-road mobility, along with a powerful gun, finally made it one of the World’s most successful tanks. Its design made it clear that sometimes agility is better than armour.
