The VK 45.01 was the official designation for an unsuccessful heavy tank prototype produced by Porsche in Germany in 1942. It was not selected for production and the Henschel design to the same specification was produced as the Tiger I. Most of the already produced chassis were instead rebuilt as Elefanttank destroyers.
Development
On 21 May 1942, Henschel and Porsche were asked to submit designs for a 45-ton heavy tank capable of mounting the high velocity 8.8 cm Kwk 36 L/56 gun which was derived from the German 88 mm Flak 37 antiaircraft gun. Both the Henschel and Porsche tanks were to be fitted with the same turret supplied by Krupp. The Porsche company worked on updating the VK 30.01 medium tank, Porsche's medium tank prototype, and adapted parts used on it for the new tank. The new Porsche tank, designated the VK 45.01 was to be powered by twin V-10air cooledgasoline Porsche Type 101 engines which were mounted to the rear of the tank. Each of the twin engines would then drive a separate generator, one for either side of the tank, which would then power each of two electric motors, one powering each track from the rear drive sprocket. But the engines and drive train were generally new and unorthodox designs for a tank, and due to being underdeveloped were prone to break down or require frequent maintenance. It was also difficult for the Third Reich to obtain additional amounts of quality copper to build whole new fleets of vehicles with electric drives in addition to the increasing demands of the U-boat fleet ; while it was easy enough to obtain quality copper to build a single prototype, once series production began, this became more difficult. These problems, and the fact that trials proved the tank to be less maneuverable than its competitor, were the reason why Henschel's identically-armed and more conventional VK 45.01 H1 prototype, which became the Tiger I, was adopted for production instead. The VK 45.01 chassis was later chosen to be the basis of a new heavy Jagdpanzer which would eventually be called the Ferdinand and mount the new, longer, 88 mm Pak 43/2. Only one tank went into service as a command tank in the Ferdinand unit, and served in Panzerjäger Abteilung 653. It was deployed in April 1944 and lost that subsequent July. The VK 45.01 's chassis and many of the Elefant's components were later used in developing the VK 45.02 prototype heavy tank.
Design
Ferdinand Porsche developed the spring rod roller carriage; there were 6 road wheels, each road wheel formed of an inner and outer paired wheel per axle. The six paired road wheels were divided into three 2-axle bogies per side, for a total of 12 individual wheels, 6 road wheels/axles, in 3 bogies. The wheels were not 'interleaved' like those of the Tiger I. The 57 to 59 tons combat weight in combination with 640 mm wide "slack-tracks" using no return rollers, produced a ground pressure of about 1.06 kg / cm2. The petrol-electric drive specially developed by Ferdinand Porsche entered "uncharted territory" for road vehicles; this led to numerous development issues with the drive system. The two air-cooled V-10 engines designated Porsche Type 101, which were merged respectively with a Siemens-Schuckert 500 kVA generator, generated the necessary electric power to operate each of the two Siemens 230 kW individual-output electric motors. In this drive system, a mechanical power transmission system and gearbox could be omitted, since now a 3-step speed switch took over the work. The electric motors transferred their power to a final drive with a ratio of 15: 1 directly to the drive wheels located at the rear. The fuel tanks carried 520 litres of petrol and allowed a driving range of 105 kilometers. Two compressed air tanks in the front crew compartment area assisted the driver during braking maneuvers. Unlike the Henschel design's mid-hull mounting for the turret, the VK 45.01 had its Krupp-designed turret mounted at the front. The turret, which mounted the 8.8 cm KwK 36 and a 7.92 mm MG 34coaxial machine gun, was essentially the same Krupp design also used for Henschel's contract-winning VK45.01 prototype design. The first eight turrets produced had lower sides and a flat roof with raised centre section to allow the gun to be depressed through a larger arc.
