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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 intended to revert the trend of 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, however their design involved only modest improvements in armour and firepower over the designs they were intended to replace, such as the Jagdpanzer 38(t), Panther G or Tiger II; and would have represented the final standardisation of German armoured vehicle design. Indeed, most of the lighter E-series vehicles were intended to use what were essentially the Tiger II's steel-rimmed road wheels for their suspension, meant to overlap each other (as on the later production Tiger I-E and Panther designs that also used them).
The E-5 was supposed to be 5-10 tonnes in weight and form the basis of a family of light tanks, reconnaissance vehicles, casemate-form turretless Jagdpanzer-style tank destroyers and armored personnel carriers.
Said to have been designed by the Klockner-Humboldt-Deutz Magirus AG firm in Ulm, the E-10 project was developed as a replacement of the Panzer 38(t) and the designs based on it. The 38(t) chassis was enlarged and redesigned. This new design was to be called PzKpfw 38 (d), d standing for deutsch ("German") as opposed to (t) for tschechisch ("Czech"). The designs based on this new chassis would all be in the 10 to 25 tonnes weight class, and using only four Tiger II-style but larger all-steel road wheels per side in an overlapping layout for its main "slack-track" suspension with no return rollers and a rear drive sprocket.
The E-25 designs, in the 25-50 tonnes weight class, were to be the replacements of all Panzer III and Panzer IV based designs, with Alkett, Argus and Adler, with involvement of the Porsche firm. This family would include medium reconnaissance vehicles, medium Jagdpanzer and heavy Waffenträger, using five Tiger II style road wheels but larger per side in a similar overlapping layout to the lighter E-10 suspension, also with "slack-track" design and a rear drive sprocket.
The E-50 Standardpanzer was intended as a standard medium tank, replacing the Panther and Tiger I and the conversions based on these tanks. The E-50 hull was to be longer than the Panther, in fact it was practically identical to the King Tiger in overall dimensions except for the glacis plate layout. Compared to these earlier designs however, the amount of drilling and machining involved in producing these Standardpanzer was reduced drastically, which would have made them quicker, easier and cheaper to produce, as would the proposed conical spring system, replacing their predecessors' torsion bar system which required a special steel alloy.
Other sources show that a variant of the narrow fronted 'Schmalturm' turret designed for the Panther Ausf. F would have been used, coupled with a variant of the 88 mm L/71 gun.
As indicated by its name, the weight of the E-50 would fall between 50 and 75 tonnes. The engine was an improved Maybach HL234 which had 900 hp. Maximum speed was supposed to be 60 km/h.
The E-75 Standardpanzer was intended to be the standard heavy tank to be used as a replacement of the Tiger II and Jagdtiger. The E-75 would have been built on the same production lines as the E-50 for ease of manufacture, and the two vehicles were to share many components, including the same Maybach HL 234 engine. The E-75 would have had much thicker armour however, and in fact compared to the Tiger II the E-75 had improved hull armour all round. As its name indicates, the resulting vehicle would have weighed in at over 75 tonnes, reducing its speed to around 40 km/h. To offset the increased weight, the bogies were spaced differently from on the E-50, with an extra pair added on each side, giving the E-75 a slightly improved track to ground contact length.
According to some sources, the similarities between the E-50 and the E-75 went further; they were to be equipped with the same turret and 88mm L/71 or L/100 gun, along with an optical rangefinder for increased long range accuracy. German scientists and engineers had successfully designed a Schmalturm, narrow-front turret and infra-red lighting and sights for use on the prototypes of the Panther Ausf. F as the war drew to a close. Other sources however, indicate that the E-75 was to be fitted with the much larger Tiger II turret, which could be adapted to accommodate an even more powerful high velocity 10.5 cm gun.
The original complex suspension by torsion bars was simplified with bogies. The standard Tiger II turret was equipped with 8.8cm KwK 44 L71 gun. The engine was an improved Maybach HL234 which had 900 hp.
The earliest ancestor of the E-100 was the Tiger-Maus. The Tiger-Maus was never built, but it was to use components from the Tiger II and the turret from the Maus.
The E-100 was to be a superheavy combat tank designed to be the replacement for the prototype-only, Porsche-designed Maus. Development and building of a prototype E-100 started in 1944 but was largely abandoned after Adolf Hitler ordered an end to the development of the Maus.
Only the chassis was finished. It was taken to the United Kingdom for evaluation purposes and eventually scrapped.
The E-100's turret would have been that of the Maus II, the proposed upgrade to the Maus. It would have housed 128 mm KwK 44 L/55 (75 rounds). Armor was 240mm-40mm.
After the war, The French designed and built the AMX-50 series of armoured fighting vehicles, which used a 1000HP Maybach engine with rear drive, as had been intended for the E-50 and E-75, whilst the idea of external Belleville washer suspension - which was also developed with the Entwicklung series in mind - resurfaced on the Swiss Panzer 61.
- "Achtung Panzer — Entwicklung Series — Jagdpanzer E-10". achtungpanzer.com. Achtung Panzer. Retrieved April 5, 2014.
- "Achtung Panzer — Entwicklung Series — Jagdpanzer E-25". achtungpanzer.com. Achtung Panzer. Retrieved April 5, 2014.
- Information about the E-100 at Panzerworld
- German Tanks of World War II: The Complete Illustrated history of German Armoured Fighting Vehicles 1926-1945, F. M. von Senger und Etterlin, translated by J. Lucas, Galahad Books, New York, 1969, ISBN 0-88365-051-7
- Special Panzer Variants: Development . Production . Operations, Walter J. Spielberger and Hilary L. Doyle, Schiffer Publishing, Atglen PA, 2007, ISBN 978-0-7643-2622-6