VK 20.01(III) Daimler Benz was awarded a contract to develop a 20-ton replacement for the Panzer III. Unlike the Z.W. 40, the VK 20.01(III) was a complete departure from previous designs. It was one of the first tanks designed to use an overlapping/interleaved road wheel suspension system (known as the
Schachtellaufwerk), which had been in use with German military half-tracks like the
Sd.Kfz. 11 as early as 1934; and had an advantage of having a shorter ground contact length for improved steering with the tank's weight distributed over larger-diameter road wheels, which lasted longer and provided a smoother ride over rough terrain. By 14 December 1938, Daimler Benz completed a design project using the HL 116, which developed 300 metric hp.
VK 20.01(D) Daimler Benz having been forced to accept untested components in their
Panzer III Ausf E, gained permission to pursue their design without interference from Wa Pruef 6. This allowed them to adopt leaf springs as torsion bars held the following key disadvantages: wasted space inside vehicle, poor access to repair and replace torsion bars, instability as a weapons platform due to the individual sprung wheels and the lack of a satisfactory shock absorber design addressing the instability. The Panzer III Ausf E's hydraulic steering, which did not function as planned, was also dispensed with. It was to be replaced with a system using mechanical levers as long as no better alternative was available. The tank design was to be completed by December 1940 and if the MB 809 diesel engine could be delivered by February 1941, a complete experimental chassis was to follow. The MB 809 had a continuous power rating of 350 metric hp, increasing to up to 400 metric hp without fuel injection. With fuel injection, its power could be increased to 450 metric hp. Design of a diesel motor was deemed necessary to utilize strategic fuel specifically demanded by Hitler. The design of the MB 809 was completed in June 1940 with the first motor running on the test stand in February 1941 followed by its acceptance test on 12 March 1941. The motor arrived in Berlin-Marienfelde to be installed in an experimental chassis. On 22 December 1941, a report to the directors of Daimler-Benz stated: "Based on experience in the Russian campaign, the new tank just developed by Daimler-Benz was now obsolete. Utilizing the already developed tank, studies were being conducted on a new design with thicker armour and heavier armament." ==Krupp==