Germany's E-Series Tanks

The Wikipedia article about Germany’s Entwicklung Series (E-Series) tanks currently includes the following sentence. “. . .  their design involved only modest improvements in armour and firepower over the designs they were intended to replace, such as the Hetzer, Panther G or Tiger II, and as such represent the eclipse of German armoured vehicle design by such tanks as the American M46 Patton, the British Centurion Mk 5/2 and Soviet T-54 tanks, which would have been the Entwicklung Series’ contemporaries and likely opponents.” I examined the talk page, but found no information about either the author of this sentence, his reasons for adding it, or whatever sources (if any) he may have relied on when formulating it.

The first thing which jumps out at me about that sentence is that the referenced Allied tanks did not go into production until long after the war was over. For example, while the British began manufacturing Centurion tanks in 1945, the Mk 5/2 version did not go into production until 1955. To compare preliminary German tank designs from 1945 with Allied tanks that were not mass produced until a full decade later seems a questionable comparison at best.

Of the three Allied tanks the E-Series article referenced, my impression is that the Centurion is the best design, the Patton the second-best, and the T-54 a distant third. One of the factors I took into account was the the success British and American tanks generally had against their Soviet counterparts in the postwar era. For example, the Israelis’ Centurions did extremely well against the T54s/T55s of their enemies.

The E-Series article noted that each tank in the E-Series was intended to be an upgrade over the tanks it replaced. The E-25 was intended to be an upgrade over the Panzer IV, the E-50 an upgrade over the Panther and Tiger I, and the E-75 an upgrade over the Tiger II. I decided to compare the statistics of the Tiger I against those of the Centurion. The Centurion Mk 2 was put into mass production not too long after WWII ended; and its weight was similar to that of the Tiger I. The Centurion Mk 3 appeared in 1948, and was basically an up-gunned Mk 2.

The Centurion Mk 2 had side and rear armor of 51 mm, as compared to 80 mm for the rear and upper side armor of the Tiger I, and 60 mm for its lower side armor. The Centurion had 118 mm frontal hull armor, compared to 100 mm frontal armor for the Tiger I. The Centurion also had the better frontal turret armor (152 mm compared to 120 mm for later models of the Tiger I). My impression is that the Tiger I’s side and rear armor were better than the early postwar Centurion’s, while the Centurion had better frontal armor. The E-50 was intended to be an upgraded version of the Tiger I and Panther, with better defensive and offensive capabilities.

In 1948, the British introduced a 20 pounder tank gun which could penetrate 287 mm of armor at a range of 1000 meters. The comparable German gun from 1944 could penetrate “only” 193 mm from that range. Upgrading a tank’s gun is typically much easier than upgrading its basic design. Dramatic improvements to both tank guns and the ammunition for those guns had been made between 1944 - '48. German engineers had developed the best tank guns and the best optics for those guns during WWII. It is unrealistic to suppose (as the author of the above-mentioned sentence seems to) that German engineers would have spent 1944 - ‘48 doing little or nothing to upgrade their tanks’ guns and ammunition. Upgrades to German tank guns and ammunition were in the works very late in the war. Additionally, the Germans had developed infrared night vision equipment, and had put it into limited deployment by the war’s end.

The E-Series did not represent the “eclipse” of German tanks by their Allied counterparts. E-Series tanks would likely have been as good as, or better than, the best of the Allies’ tanks. However, the margin of superiority would have been reduced, in large part because the Allied tanks of 1943 - '44 had so much more room for improvement than did their German counterparts. On the other hand, as tanks developed the ability to kill each other at longer and longer ranges, an increasing premium would have been placed on optics. This was an area in which the Germans had maintained a significant advantage over their Allied counterparts throughout the war.

A German general once said to the Americans, “One of our tanks is worth ten of yours. Unfortunately, you always have eleven.” The E-Series tanks were intended to dramatically reduce the production gap that statement implied. E-series tanks would have been much simpler and easier to produce, and more mechanically reliable, than the tanks they replaced.

Later in the war, Germany’s tank advances often bogged down for three reasons: 1) lack of numbers, 2) too many tanks breaking down due to mechanical complexity and unreliability, and 3) lack of fuel. The E-Series tanks would have allowed Germany to overcome the first two of those obstacles to major tank offensives.

@Gargantua:

I’ve had the privelidge of sitting in a Konig’s Tiger.  It’a almost 9 ft tall,  and something like 70 tons.

A total MONSTROSITY!

The fuel consumption was a LITRE of Diesel per Kilometer….

Even with the new designs, of which I’m quite familiar… without proper fuel/energy resources available, you might aswell cancel the war effort all together.

The König’s Tiger (a.k.a King Tiger) was hands down the best tank of the war. I envy you your chance to sit in one! :)

You bring up a very good point about fuel consumption. Later in the war, Germany lost many more tanks due to lack of fuel/mechanical failure than to the action of enemy tanks. While the E-Series tanks would have been more mechanically reliable than their predecessors, that wouldn’t have solved the problem of lack of fuel! As the war drew on, Germany’s options for winning–or even for escaping hostile foreign occupation–grew less and less. By the autumn of '44 at the very latest there was nothing Germany could possibly have done to avoid total and catastrophic defeat.

@Gargantua:

They should have gone straight for the BOMB, that would have sorted the Russians out!

Wow imagine a sci-fi movie, with Germans coming out of helicopters, and attacking with E-Series tanks LOL.  Awesome….  reminds me of Return to Castle Wolfenstien, close to the end, when you’re at a V2 facility, and you get attacked by elite paratroopers…  one of the best electronic memories I remember…

What we should discuss Kurt, is how DOCTORINE determined German armored success, much more so, than just the armor itself.   Hence Blitzkrieg, Tank Terror, and the fall of france.

Your comment about doctrine speaks to the heart of the issue. In the Battle of France, the Allies had roughly as many tanks as did Germany. In 1939, Germany had nothing but obsolete light tanks. By 1940 a reasonable number of medium tanks had been added to its force. But even German medium tanks were no match for tanks like the French Char B1. One Char B1 survived with little damage, despite having taken 140 hits from medium German tanks!

As you hinted at, Germany made up for this with better doctrine. The first step of blitzkrieg was to concentrate overwhelming land and air power on a small point of the enemy lines to achieve a breakthrough. The second step was to use tanks and mechanized infantry to create a breakout advance. Stuka dive bombers would soften up the armies immediately in front of the breakout force, and would also be employed against surrounded pockets of enemy soldiers. Twin engined bombers would destroy vital bridges and rail lines, thereby crippling the enemy’s ability to respond to the rapid advance. This kind of lightning war was based on strategy and speed. The tank force Germany used was well-suited to this doctrine in several respects. The tanks were reasonably mechanically reliable and fast. Also they were not fuel hogs, at least not by the gas guzzling standards of tanks! Each tank had its own radio, which made it easier for tank commanders to coordinate their forces.

Similar tactics were used to achieve the overwhelming initial success of Operation Barbarossa. Germany experienced less than 300,000 soldiers killed or captured, as opposed to 4.1 million for the Soviet Union. Even though the Soviets had an overwhelming numerical advantage, they could not sustain an exchange ratio like that!

However, blitzkrieg tactics would later prove less effective against the Soviets, for the following reasons.

1. The T-34 was much better than any German tank of 1941. Unlike the French Char B1s, the T-34s were highly mobile.

2. After the Soviet leadership saw how well the T-34s did in combat against the Germans, production efforts were centered on producing those tanks, instead of the far less effective light tanks which had constituted so large a portion of the Soviets’ pre-Barbarossa tank production.

3. The Soviets learned the importance of using layered defense and of mobile reserves. If the Germans achieved a breakthrough, a force of T-34s would be on hand to counter German tanks.

4. In the year 1942, the Soviets produced four times as many tanks as did Germany.

5. The German supply situation was wholly inadequate to sustain operations that far from Germany. These supply limitations meant that the German Army did not receive the food, fuel, ammunition, medical supplies, or winter uniforms it required. This was especially true during and immediately after major advances.

6. Germany’s inadequate supply situation meant that large numbers of German soldiers died from cold, hunger, and disease. During Operation Barbarossa, Germany lost more soldiers to those causes than to enemy action.

7. Just because a Soviet force was encircled on paper, does not necessarily imply airtight encirclement in fact. Soviet soldiers often found a way to leak through German encirclements. While encircling and capturing or destroying Soviet forces was still a useful activity, the rewards for doing so were far more limited than they would have been had encirclement been airtight.

One of the reasons Germany had adopted blitzkrieg tactics in the first place was because Hitler had adopted Guderian’s plan for invading France. This went against the advice of the majority of his generals, who were far more conventional in thinking than Guderian. (Though they were still less conventional and more able than all but the very best Allied generals.) There were other times when Hitler sided with the conventional thinkers. The Battle of Kursk is a clear example. Von Mannstein strongly argued against launching the attack precisely because it was so predictable. Instead he recommended launching an attack to the south, in a place where the Soviets would not expect it. Instead, Hitler listened to the advice of the majority of his generals, and threw an attacking force into the teeth of Soviet defenses six layers thick. That decision represented conventional military thinking, not the kind of outside-the-box, innovative thinking Germany absolutely had to employ if it was to overcome the Soviets’ overwhelming advantages in manpower and industrial strength.

By 1943, Germany had solved some of the tank-related problems described earlier. Its Panther and Tiger tanks were individually superior to T-34s. Its medium tank models had received upgrades to help close or eliminate the gap with T-34s. However, Panthers and Tigers were complex, difficult to manufacture, and prone to mechanical breakdowns. This proved very serious during the Battle of Kursk. Within a few days of the start of the battle, most of the Panthers and Tigers allocated to achieving the initial breakthrough were out of action–not because they had been destroyed by the enemy, but because they’d broken down.

If Germany had had the manpower, industrial capacity, and natural resources to continue competing with its enemies, the E-Series tanks could have allowed it to resume its use of blitzkrieg tactics. My sense is that E-50s and E-75s would have been qualitatively superior to the T-44s and T-54s the Soviets would build in the late '40s and early '50s. As tanks gained the ability to kill each other from farther and farther away, an increasing premium would have been placed on optics, range finding technology, and infrared night vision. These were areas in which Germany had a decisive edge over the Allies.

The simplicity of the E-series designs would have allowed them to be produced in large numbers, and would have solved the mechanical reliability issues associated with early model Panthers and Tigers. Additionally, the E-50 was intended to be significantly faster than its Panther forebears (60 km/hr, compared to 43 km/hr for late model Panthers). Germany’s tank force would have been numerically comparable to its Soviet counterpart, its tanks would have been individually superior, they would not have been plagued by mechanical breakdowns, and they would have had the speed necessary to exploit initial breakthroughs.

@221B:

Blitzkreig depended on having air superiority more than having superior tanks.  Germany had this in 1939 to 1942.  Germany did not have this in 1943 to 1945.  Therefore Germany was able to conduct large-scale offensive actions early in the war, but could only be defensive late in the war.

While the tanks are very important (especially when poor weather grounds the planes), the tanks and troops do not move when being attacked from the air.  They also do not move without fuel which may be cut off by airpower.  They also do not move when they do not have sufficient replacement parts as the factories have been destroyed by bombing.  Consider carefully the battle of the bulge…it was good weather more than anything else which stopped the Germans and saved the allied holdout at Bastogne since the allies were then able to resume aerial attacks.

To regain the initiative, yes Germany needed superior tanks, but also needed large numbers of the ME-262 planes and trained pilots for them, which it was unable to produce in sufficient quantities to alter the air war.

You are absolutely right about the importance of air superiority to blitzkrieg. Germany produced 41,000 military aircraft in 1944–a huge step up from the 15,000 military aircraft it had produced in '42. But unfortunately for the Axis, the U.S. produced 96,000 military aircraft in '44, the Soviet Union produced 40,000, and the British produced 26,000. While some of those aircraft were required to deal with the 28,000 military aircraft the Japanese had produced that year, most of them were sent against Germany.

Germany produced 1,400 Me 262s during WWII. However, “As few as 200 Me 262s made it to combat units due to fuel shortages, pilot shortages, and the lack of airfields that could support the Me 262.” Me 262s achieved a 5:1 exchange ratio against enemy planes.

The construction of jet engines required rare metals which Germany obtained from Spain. After the Allies conquered France, Germany’s Spanish rare metals supply was cut off. Due to Germany’s shortage of required materials, the jet engines it produced later in the war tended to wear out very quickly. The obvious solution to that (and many other) problems would have been to stop the D-Day invasion. Had Germany achieved air superiority, the probability of a successful Allied D-Day invasion would have been greatly reduced, or eliminated outright.

Back in 1940, Goering dramatically reduced the number of engineers allocated to the development of the Me 262. Suppose Goering hadn’t been quite so shortsighted, and had increased (rather than slashed) funding for the Me 262 development program. Had this occurred, it’s possible to imagine Germany shifting the majority of its aircraft production capacity to Me 262s by late '43 or early '44.

Given that Germany produced 41,000 military aircraft in '44, one could reasonably ask what might have happened had 30,000 of those aircraft been Me 262s. With the aforementioned 5:1 exchange ratio, those 30,000 aircraft could have balanced out 150,000 enemy aircraft. The Allies produced 164,000 military aircraft in 1944, a portion of which were needed for use against Japan. Massive production of the Me 262 would have allowed the Germans to achieve air supremacy on their eastern front and air parity or superiority in the west. Once the R4M rocket was introduced, the equation would change still further in Germany’s favor, and the possibility of daylight Allied bombing raids against German cities would end. This would allow for further increases in the production of Me 262s.

This improved aerial situation would help Germany’s land war both directly (by preventing the D-Day invasion and by letting it use airplanes to shoot Soviet solders) and indirectly (by allowing it to divert forces away from France and into the eastern front). Together, these two factors might be enough to stabilize the eastern front, or at least to significantly slow the pace of the Soviet advance. I do not think that the Me 262 alone would necessarily have prevented Soviet conquest of Germany. But if one other major factor could have been added to the mix–such as E-Series tanks, or widespread deployment of the assault rifle–the combination of that new land weapon and Germany’s jet power would probably have been enough to push the Soviets back.

Had Germany ultimately succeeded in conquering the Soviet Union, it would have received a massive increase to its labor force, industrial capacity, and access to natural resources such as oil. If Britain and the U.S. subsequently achieved technological parity with Germany, Germany’s access to these things would still make conquest a very difficult proposition indeed. The Western democracies might be forced to abandon their demand for unconditional surrender, and to agree to a peace which would preserve the existence of both Germany and the Western democracies.

@Lazarus:

Even if all this fantasy scenario was true (and it was not) then all it would do was swap the words ‘Berlin’ and ‘Hiroshima’.
Either way the superior Allied technology triumphs.

Let’s start by pretending that, in 1940, Goering had increased funding for Germany’s jet program. (The historical Goering had slashed funding for the German jet program in 1940.) Suppose that funding increase had allowed Germany to switch most of its military aircraft production to jet aircraft by '44. (Thereby preventing D-Day and improving its fortunes on its eastern front.) Would the United States still have been able to drop an atomic bomb in late 1945?

The U.S. did not have, and was not close to developing, ICBM technology during WWII. This meant that any American atomic bomb had to be delivered via a bomber. Bombers which could be shot down by German jets. A daylight atomic bombing raid would have been nearly impossible under the scenario I outlined earlier. A nighttime raid would be more likely to succeed. However, both sides improved their radar technology as the war went on, thereby partially negating the invisibility conferred by the night. An attempt to deliver a nuclear payload to Berlin at night may or may not have succeeded.

If it had, Germany might have retaliated. You could point out that Germany had not made the massive investment in the development of nuclear technology that the United States had made; and therefore lacked nuclear weapons with which to retaliate. What Germany did have was nerve gas technology that was years ahead of any other nation’s. It also had the ability to deliver this gas to England, either via its jet aircraft or V2 rockets. A series of V2s, each carrying a nerve gas payload, could have caused as many deaths in London as an atom bomb would have caused in Berlin.

In addition, Germany’s engineers were in the process of developing its  Aggregate Series rockets. After the war, Werner von Braun and his team of German rocket scientists moved to the United States. The German rocket scientists became the core of America’s rocket science effort, and the Saturn V rockets they designed were based on the Aggregate Series rockets Germany had developed during the war. The A4 (a.k.a. the V2) is the most famous of the Aggregate Series rockets. But the Aggregate Series also included the A10, which was a much larger rocket than the A4, and would have had the range to hit the United States. The A10’s projected first flight had been scheduled for 1946. Also under development was the A12, a rocket capable of putting 10 tons of cargo into Low Earth Orbit.

Had the United States attempted to end the war with nuclear weapons, it would have faced three obstacles. 1) German ability to use jet aircraft to shoot down piston-driven American bombers. 2) The United States’ extremely limited ability to produce nuclear weapons. 3) Germany’s ability to retaliate against nuclear attacks, first against Britain, and in subsequent years against the United States as well. Far from forcing an end to the war, the use of nuclear weapons under the circumstances I’ve described would instead have made the war more destructive, and the civilian death toll much higher. At that point, the war would have become a contest to see which side was willing to pay the higher price for victory. I believe that Germany would have been willing to pay a higher price to avoid hostile foreign occupation than the Allies would have been willing to pay to impose a hostile foreign occupation on Germany. Also, the voters in Western democracies had the option of voting in peace candidates, whereas the voters in Germany did not.

@Lazarus:

Whatever scenario I come up with you change the  conditions  to give Germany the advantage.
In other words you are going to rig every possible outcome to make sure your ‘side’ wins.

The only chance Germany had would have been if she developed a nuclear powered horse for her infantry Divisions.

Your post is inaccurate. I was the one who had initially formulated a scenario. I wrote:

I do not think that the Me 262 alone would necessarily have prevented Soviet conquest of Germany. But if one other major factor could have been added to the mix–such as E-Series tanks, or widespread deployment of the assault rifle–the combination of that new land weapon and Germany’s jet power would probably have been enough to push the Soviets back.

Had Germany ultimately succeeded in conquering the Soviet Union, it would have . . .

You responded to that scenario by claiming that the U.S. would have won the war anyway through the use of nuclear weapons. I responded by pointing out that this was not necessarily the case. I did not “change the conditions of the scenario” as you have falsely claimed. Nor is there any truth to your assertion that I would “rig every possible outcome to make sure [my] ‘side’ wins.” This is not the first, second, or fifth time you have misrepresented something I’ve written. You’ve done this often enough I must assume you’ve adopted misrepresentation as a deliberate strategy. What do you hope to gain by your use of that strategy?

@Gargantua:

Don’t ruin it Laz, I’m enjoying the mental picture.

Thanks for helping move this discussion back to one of military history or alternative history. (As opposed to a petty personal squabble.) I think a lot more people came here for the former than the latter!

Is there some aspect of the E-Series program or the other subjects which have come up in this thread you’d like me to discuss in more detail?

@Gargantua:

How would the Allies have countered?  I mean… there is always a counter…

A good question.

If Germany had begun mass producing E-Series tanks in 1944, there would have been no need for an Allied counter. By that point, Germany’s military situation was bad enough that large numbers of E-Series tanks, alone, would not have been able to salvage it. But the E-Series tanks might have slowed the pace of the Allied invasion, and there are several things the Allies could have done to have sped that process back up.

1. Go after Germany’s fuel supply even more strongly than they did. In the real war, German tanks were often lost to lack of fuel, as opposed to the action of enemy tanks. One of the intended advantages of the E-Series program was the massive increase in German tank production it would have allowed. One of the effects of all those extra tanks would be to worsen Germany’s fuel situation.

If fuel was going to be a bad problem for Germany anyway, it would have been logical for the Allies to make it even worse. During the months immediately before and after D-Day, the Western democracies suspended extermination bombings targeted against German cities in order to focus Anglo-American air power against German targets in France. After the Allied invasion of France was well underway, Britain and France resumed their policy of destroying German cities.

If the E-Series tanks had been considered a major problem, Britain and the U.S. could have abandoned their policy of anti-civilian bombings in favor of using that air power even more strongly against German oil refineries, as well as the trains and trucks necessary to transport fuel to Germany’s tanks. This is not to say the Allies weren’t aggressive against such targets in the historical war, because they clearly were. But they could have been even more aggressive by eschewing anti-civilian bombing raids.

2. Destroy Germany’s tanks from the air. The P-47 Thunderbolt and Il Shturmovik were excellent in the ground attack role. The Western Allies had outright air supremacy against the Luftwaffe, and the Red Air Force did increasingly well against the Luftwaffe as the war went on. Germany tried to have tanks move only at night, and conceal themselves during the day. But that strategy was only partially effective at preventing destruction from the air.

3. The Allies could have moved forward with their own more advanced tank designs. Small numbers of Pershing tanks began appearing in Europe toward the end of the war, even despite internal resistance to the idea of a heavier tank. The British Centurion tank was a good design for a heavier tank. Also, my opinion of the Soviets’ T44/T-54 has improved after having done more research. Had Germany begun producing large numbers of E-50s and E-75s, it would have caused the Allies to (if possible) accelerate the deployment of their own tanks in the 50 ton range.

A 1944 introduction of the E-Series tanks would not have been enough to stem the tide of the Soviet advance, or of the Anglo-American invasion of Italy. They probably would not have been enough to throw the Normandy invasion back into the sea. But even if the E-Series tanks had caused the D-Day invasion to fail, the Allies would continue to have gradually gained ground at Germany’s expense, while killing or capturing German soldiers of military age at a much faster pace than it could replace them.

But if Germany had begun producing large numbers of E-Series tanks in 1942, they would have exerted significantly more influence on the course of the war than a 1944 release date would have implied.

In 1940, Germany’s strategic position was bleak. The concern was that over the long run, Germany would be unable to match the military aircraft production of Britain + the American aircraft being sent to Britain. The invasion of the Soviet Union was an attempt to change that strategic equation in Germany’s favor by providing it with the manpower, industrial capacity, and raw materials necessary to compete with Anglo-American air production. However, the Soviet Union’s prewar population was 169 million, as compared to 69 million for Germany. The gains Germany achieved in 1941 were important, but not enough in themselves to achieve victory over the Soviets.

The E-Series, if deployed in 1942, would have given Germany three things. 1) A manyfold increase in the number of tanks it could build. 2) Tanks which were much more mechanically reliable and less likely to break down. 3) Tanks which were qualitatively superior to anything the Soviets had. These three factors would probably have been enough to allow Germany to achieve large gains in 1942. These gains would have been important for three reasons: 1) The Soviet soldiers captured and army groups destroyed, 2) the increase in Germany’s war-making potential brought about by the Caucasus oil fields and other natural resources captured, and 3) Reduction in the Soviet Union’s population and industrial base.

It’s possible that, with the E-Series tanks, Germany would have gained half as much land in the summer of '42 as it had in the summer of '41. (In the historical war, the Soviet Union experienced significant local defeats in the Caucasus area in the summer of '42, but lost only a small fraction of the land it had lost in '41.) Once the Caucasus oilfields were in German hands, oil would no longer have been a problem for Germany. (And might have become a problem for the Soviet Union.)

After a summer offensive such as this, one of two outcomes would have been possible. 1) Germany and the Soviet Union might have signed a peace treaty. 2) The two sides might have decided to continue fighting until one had been fully destroyed.

Stalin’s rationale for choosing the first option would have been because of his ongoing diplomatic policy. He regarded Germany and the Western democracies as equally enemies, and wanted to see the two sides kill as many of each other’s soldiers and civilians as possible in a war which did not involve the Soviet Union. A peace treaty would have let him sit on the sidelines, instead of bleeding away the Red Army’s strength to do something (destroy the German Army) that he wanted the Western democracies to do instead. Hitler’s rationale for agreeing to peace would have been to allow himself to focus on getting out of the war against the Western democracies, without also being further subjected to the meat grinder of an anti-Soviet campaign. The peace treaty with the Soviets would allow him to use his Caucasus force to invade Persia, sweep south and east, and ultimately unite with Rommel in Libya. Hitler could continue this land war until the British had also lost India and sub-Saharan Africa. While the loss of so much of their empire may or may not have been enough to convince the British to agree to peace, it might have helped get Churchill out of office. (Which would definitely have been a step toward a peace treaty.) Also, Britain’s ability to wage war would have been significantly weakened by the loss of the bulk of its empire.

If the war between Germany and the Soviet Union had continued into 1943, then under the E-Series scenario it’s likely that Germany would have continued gaining Soviet territory. It is very unlikely that Germany would have suffered a Stalingrad-like defeat if it had had E-Series tanks, primarily because the overall military situation would have been considerably more favorable. The Soviet Union would have had a much greater ability to recruit and replace troops than Germany. But at least during '43, that strategic advantage would have been balanced out by a series of German tactical victories, and one-sided exchange ratios as Germany used its tanks to encircle and capture large groups of Soviet soldiers.

On the other hand, the British and American armies would have become an increasingly large problem for Germany. This would be even more true in 1944 than 1943. Therefore, Germany would need to capture Moscow and other key Soviet cities in '43 or early '44, before the weight of the Anglo-American armies could be fully brought to bear. If a Normandy-style invasion was successful–as it very well could be because of American air power–and if Germany was still engaged in a land war against a powerful Red Army, it could spell defeat for Germany. To avoid this fate, Germany would have to conquer as much Soviet territory as possible, as quickly as possible, in '42 and '43. Then, it would have made sense for Hitler to have sought a peace treaty with the Soviets at the end of '43, contenting himself with whatever Soviet land Germany had been able to conquer during the three year war between the two nations. That peace treaty would free up the bulk of German military strength for use against whichever British and American forces had been sent to destroy the Reich.

These actions would secure Germany against the short-to-intermediate term threats of a land invasion from any direction. Germany would also have the industrial capacity necessary to stay within shouting distance of Anglo-American aircraft production, and would have the oil necessary to get its planes into the air. The pace of the war would then slow down (except for fighting in Africa and the Middle East). This slowdown in combat would allow Germany to take benefit from the technological edge it had started to build late in WWII. Late in the war, Germany had the world’s best jets, rockets, air-to-air and air-to-surface missiles, and best poison gas. (The last being a possible tool with which to retaliate against any nuclear bombs dropped on Germany.) In a struggle like this, Hitler would probably have continued to try to get the Western democracies to agree to cease fighting, while keeping the borders as they were. What would have happened if (when?) the Western democratic leaders ignored or refused these offers for peace, is not fully clear.

Just to add to this thread, here is a YouTube video about the E-Series tanks.