The German E-series tanks (Entwicklung, "project") are especially renowned among German vehicle enthusiasts. The most famous of those is the heaviest of the proposals, the E-100. Alongside the Maus, this tank is often called a wonder weapon which would give the Third Reich a way to change the tide of war. In reality, the abilities of the tank are grossly overestimated. Additionally, the "canonical" history of its creation is omissions and mistakes. Even the external view of the tank, composed by Walther Spielberger, is not the same as what would have been in reality.
In June of 1942, Porsche proposed its superheavy Maus tank. The draft was drastically different from what would eventually end up in metal. Outside, the tank was reminiscent of a larger Lowe, developed by Krupp. The initial design weighed 120 tons and had a 149 mm gun, 37 calibers in length. In June, on Hitler's orders, the armour was thickened, and a secondary turret with a 75 mm gun was added. It was decided that the proposed tank, already at 140 tons, would have to be redesigned. Effectively, it was going to be a whole new tank, with little of the original Tiger-Maus.
Porsche's brainchild had to be altered, but this change of course sealed the fate of Krupp's design. The Lowe, a project in development since 1941, was cancelled in July of 1942. However, Krupp did not lose everything: they were still developing the turret and gun, and the hull production was going to start in Hessen anyway. The company still had hope that they could have their revenge and regain lost profits.
The new round of competition between Krupp and Porsche started on September 11th, 1942. At a meeting between representatives of the 6th Weapons Department and Krupp representatives, the Maus turret was discussed. Lieutenant Colonel Fritz Holzhauer was worried about the many completely new components in Porsche's tank, including the engine. Lieutenant Colonel Felfert, responsible for Krupp's tank building branch, took full advantage of this fear. An alternative to Porsche's design was proposed, a tank that would weigh 150 tons and use as many components from the Tiger as possible. Holzhauer supported the idea and proposed that it be reviewed in a month.
This was not the first time that Krupp made such a move. Six years before these events, Krupp, initially chosen as the producer of a turret for the BW medium tank (future PzIV) managed to get permission to produce two prototypes of an entire tank, and as a result beat out the Rheinmetall design. And now, under the excuse of simplification, Krupp was about to make a tank out of a turret. It is worth noting that the "Tiger" here is the Tiger II. This is clearly indicated by the mass of the "donor" vehicle in question: 65 tons.
By mid-November, the alternative superheavy tank was ready. Unofficially, it was named "Tiger-Maus", but in NARA documents, it's called Krupp-Maus. Unlike Porsche, Krupp's engineers did not cover up the suspension with the hull. A unique solution allowed making the tank both wider than the railroad gauge and narrow enough to fit on a train. Like the Tiger and Tiger II, the tank had special transport tracks. Additionally, the sides were protected by armour plates, which could be removed for transport. The equipment to mount and demount the plates was attached to the turret. There were two versions of this project: blueprint W1671 proposed moving the turret back. This is about the same time as when Porsche's turret was moved (blueprint K3385, November 14th, 1942).
Krupp's revenge did not work out from the beginning. Calculations showed that for a 150 ton Tiger-Maus, even an engine turbo-charged to 1000 hp would not give it a maximum speed over 20 kph. With a stock Maybach 230, the result was even more sad: an effective hp/ton of 4.51. To compare, the British Infantry Tank MkI had an effective power of 5.98 hp/ton, and could go no faster than 13 kph. A similar speed was predicted for the Tiger-Maus with Tiger II components. To summarize, the commission (which, by the way, included Ferdinand Porsche) saw more drawbacks than advantages in Krupp's proposal.
A feverish search for a new engine began. Engines that were planned for the Maus worked, but they were not in mass production, and took away the major feature of the Tiger-Maus, the speed at which it could be put into production. Similar issues arose with the transmission and other components. The problem was compounded by the fact that the tank's mass grew month after month, reaching 170 tons in November.
On November 30th, 1942, a draft of the 170 ton Tiger-Maus was made (blueprint W1674). The mass of the chassis was 122 tons, 82 of which were for the hull. The proposed engine was the MB.507, the same as on the Maus. The removable side armour concept remained. The road wheels were planned to be 650 mm in diameter, less than on the Tiger II.
The result of the project review on December 1st, 1942, led by a key figure of the 6th Weapons Department, Heinrich Kniepkamp, was not promising. This Tiger-Maus was simply unnecessary, as it could not be rapidly put into production. With a mass of 170 tons, one could forget about using the engine, turning mechanism, transmission, or any other elements of the Tiger II. Only the reduction of mass by reducing side armour thickness was met with approval.
One week later, on December 7th, Krupp proposed a new version of the project (blueprint W1677). The mass of the Tiger-Maus dropped to 130 tons, the wheels were increased to the same 800 mm diameter as on the Tiger II. According to calculations, the top speed of the tank would be 23 kph, but considering the effective power of 5.4 hp/ton, this was overly optimistic. At the same time, an alternative variant (W1681) was prepared with a rear turret.
The commission that reviewed the project on December 8th immediately rejected the rear turret. The main variant was met with approval, as it reused many Tiger II components. The tank's suspension was to be torsion bar based, and a prototype was expected for fall of 1943.
Kniepkamp and Krupp's joy was not meant to last. On December 15th, Holzhauer decided to keep only one Maus after consultation with the OKH. Hitler himself decided that Porsche's tank was more promising, and the Tiger-Maus was forgotten, only to later return under a different name.
In early March of 1944, Adlerwerke company from Frankfurt auf Main submitted blueprint 021A38300 for a super-heavy tank called E-100. This project would be the heaviest tank of the E-series, the idea of which was proposed by Kniepkamp in April of 1943 (in other sources, the E-100 project was started in June of 1943). The concept was for a series of vehicles with external suspension elements. The Adlerwerke team, headed by Karl Jenschke, would only work for the suspension, not only of the E-100, but of the E-75 and E-50. This is worth noting, as Adlerwerke is often credited with the E-50, E-75, and E-100 entirely, which is not correct.
According to the blueprints, the 140 ton tank would be armed with a 149 mm gun and a 75 mm gun. Two types of engines were proposed: one was a 700 hp Maybach 230, with a transmission and turning mechanism borrowed from the Tiger II. The estimated top speed was 23 kph. The second variant would have a new 1200 hp Maybach engine. Nothing specific was said about its transmission or turning mechanism. The top speed of 40 kph, at 8.57 hp/ton, was also very optimistic. The tank's main feature was the already familiar removable side armour and transport tracks to reduce width.
A maximum speed of 23 kph, removable armour, engine, transmission, and turning mechanism from the Tiger II? This seems very familiar. No, there was no mistake, this is almost an identical copy of the Tiger-Maus with a suspension from Adlerwerke. Instead of a torsion bar suspension, springs were proposed, and new 900 mm road wheels. The blueprint's authors did not even design a new turret: the Maus had an identical one on blueprint K3387, dated January 1st, 1943. The turret lasted for two weeks, after which it was replaced with a nearly year-old design: a 15 cm L/37 gun, one that was rejected in March of 1943.
Kniepkamp did not try very hard conceal the fact that his "new" tank was a year-old project pulled out of the dusty closet. Initially, he tried to convince Holzhauer that this was a new tank developed by a new company. In reality, Krupp was behind this project, and the Tiger-Maus was resurrected due to the restart of the Maus program. Kniepkamp's logic was sound: the E-100 was a simpler and lighter superheavy tank.
The tank would certainly not have received the same turret as in blueprint 021A38300. The 149 mm gun was rejected in March of 1943, and the turret itself changed significantly since then. In March of 1944, Krupp started work on a new turret, known as Maus II. The curved front was removed, the turret became easier to produce, and the guns (128 mm KwK L/55 and 75 mm KwK L/36) were placed on top of each other. Another important addition was a rangefinder. The E-100 was supposed to receive the same turret, but with a reduced mass to 35 tons. This was achieved by reducing the thickness of the side armour to 80 mm.
Despite Kniepkamp and Krupp's enthusiasm, the E-100 was not seen as a magic solution to all problems. By spring of 1944, an experimental Maus prototype was driving around Boeblingen, and work on the second prototype already started. All components for Porsche's tank were more or less finalized. The idea of rapidly building a competitive tank based on Tiger II components became impossible. The difference in mass between 140 and 189 tons was not that much, as in either case, specialized train platforms would have to be used. Finally, the armour of the Maus, especially on the sides, was greater than that of its competitor. There was little necessity in the E-100.
All that E-100 lobbyists managed was to receive permission to build one prototype with a dummy turret. This permission was given based on the potential use of the E-100 as a tank destroyer with either a 15 cm StuK L/63 or 17 cm StuK L/53 gun. It's evident that the first proposal was to install these guns in a rotating turret, but that trick would not fly. The Maus was not suitable as a chassis, as its hull was too tall. As a result, it was approved as a chassis for the StuG E-100. This was the purpose for which the chassis was being built, but Kniepkamp and Krupp retained hope that they could still push their tank through to replace the Maus.
On July 10th, 1944, Hitler gave an order to stop work on all superheavy tanks and SPGs. The orders were followed, partially. Changes were still made to the Maus, to the point of replacing the gasoline engine with a diesel one. These changes only stopped when both prototypes were moved to Kummersdorf, where Porsche could no longer tinker with his "children". The situation with the E-100 was even more comical: while Porsche was secretly tuning his creation, its competitor was still secretly being assembled.
The site of assembly was a Henschel proving ground in Haustenbeck, not far from Paderborn. This choice was not a coincidence: the project used Tiger II components, so Henschel was an interested party. Due to the critical situation on the front and overloaded production, assembly went slowly. By January 1945, the hull and engine compartment were mostly ready. The suspension was also partially assembled, but since Adlerwerke could only spare three men, and the springs were lost in the mail, it was not ready. Judging by the state of the tank after the war, the springs were never found.
In May of 1945, the unfinished chassis fell into the hands of the Allies. The Americans limited themselves to examining the vehicles at Haustenbeck. The British had other plans. By the time the E-100 was captured, it was partially disassembled by Germans. It seems that the British managed to find the missing springs, since in the summer of 1945, the suspension was completed and the tank was pulled out of its garage.
All available E-100 parts were loaded on a superheavy trailer, and the tank began its journey towards the home islands, along with many other vehicles from the test site. Tracks were not installed on the vehicle until it reached England. There are rumours that the tank underwent trials, but they are unwarranted. The tank remained at the Bovington school until the 1950s when it was sold for scrap metal, along with most vehicles that arrived from Haustenbeck.
You may note that this story differs from the "canonial" one. Turns out, the perfect wonder-weapon was a rejected design that lobbyists tried to push through a second time. It had no advantages over the Maus. The E-100, as with the whole E-series, is one big question mark. As of March 1945, not a single E-series tank was listed in a production proposal, which speaks volumes.
Original article by Yuri Pasholok.