Under the Versailles Treaty, Germany was not allowed to build tanks. After the Nazis broke free of that treaty in 1933, Germany began engaging in tank design. By 1939, it had a somewhat decent light tank design in deployment. By 1940, it had added a moderate number of medium tanks to its unit mix. (Its quest for a good tank design was aided by the acquisition of Czechoslovakia in 1938.) But in 1941, it became clear that none of Germany’s tanks were the equal of the T-34.
In response, Germany hastily designed new, heavier tanks; such as the Panther and Tiger. Like many other German tank designs, these were overly complicated and difficult to build. Assuming the ability to reverse engineer the T-34 in the first place, Germany should have used that as its stopgap tank design until it could put better tank designs into production.
These better tank designs were already in the works.
The Entwicklung series, more commonly known as the E-series, was a late-World War II attempt by Germany to produce a standardised series of tank designs. There were to be standard designs in six different weight classes, from which several specialised variants were to be developed. This was necessitated by the extremely complex tank designs that had resulted in poor production rates and mechanical unreliability.
The E-series designs were simpler, cheaper to produce and more efficient than their predecessors. . . .
The E-50 Standardpanzer was intended as a standard medium tank, replacing the Panther and Tiger I and the conversions based on these tanks. . . . Compared to these earlier designs however, the amount of drilling and machining involved in producing these standardpanzers was reduced drastically, which would have made them quicker, easier and cheaper to produce, as would the proposed conical spring system, replacing their predecessors’ complex and costly dual torsion bar system. . . .
The E-75 was the intended replacement for the Tiger II. E-75s would have had 185 mm armor in the thickest places; and 85 mm armor where it was thinnest. This compares to 100 mm armor on the front of a T-55; and 60 mm armor in the rear. The E-75 would have used infrared lighting and sights; and a high velocity 105 mm gun.
However, the war ended before Germany’s E-Series tanks were put into production.