Panzer IV/70(E)

German Reich (1944)
Self-Propelled Anti-Tank Gun – 1 Incomplete Prototype

During the Second World War, the German Army officials wanted to improve the overall performance of their Panzer IIIs and IVs. One such project involved combining a number of elements from both tanks into a new design. In addition, new elements, such as an improved suspension and superstructure with angled armor were also to be added. The project was simply designated as Panzer III/IV, on which a self-propelled anti-tank variant was also developed, named Panzer IV/70(E).

The Panzer III/IV project

Incorporating components from the Panzer III and IV into a single-vehicle was something that the Germans tried doing even before the start of the war. Early during the Panzer development, Wa Pruef 6 (the office of the German Army’s Ordnance Department responsible for designing tanks and other motorized vehicles) wanted to redesign the Panzer IV Ausf.C in order to be equipped with the newly developed Panzer III torsion bar suspension. For this reason, at the start of June 1937, Krupp, at that time, the sole Panzer IV manufacturer, was asked to cease any further work on the Panzer IV chassis. However, with the development of the Panzer III Ausf.E chassis was running at a slow pace due to the introduction of a new torsion bar suspension and a new transmission It was estimated that the first experimental chassis could not be built prior to April 1938. As there was a large demand for Panzer IV support tanks, in October 1937, Krupp was informed to continue working and producing Panzer IVs in their current form, which would remain basically the same until the end of the war.

The consolidation of the two different designs into a single-vehicle offered many advantages: reducing the cost of production, increasing the availability of spare parts, etc. But, as these two vehicles were becoming obsolete and the focus moved to more advanced tanks, such as the Tiger and Panther, the development of a Panzer III/IV hybrid was seen as redundant at that point.

But this was not the end of the story. In 1943, using components from both tanks, a new chassis, designated as Geschutzwagen III/IV, was developed. This was used for numerous projects, but the best known and which were actually produced and used in combat were the Hummel self-propelled artillery and Nashorn self-propelled anti-tank vehicles.

The idea of building a Panzer III/IV vehicle, while initially discarded, was not completely abandoned. In January of 1944, a Panzerkomission (tank commission) was formed to once again determine how the Panzer III/IV hybrid should be further developed. This vehicle was to be designated as Panzerkampfwagen auf Einheitsfahrgestell III/IV Ausf.A, or more simply known as Panzer III/IV. It was agreed by the tank commission, that this new vehicle would use the modified chassis and the engine of a Panzer IV, with the steering gear, transmission, and final drives from the Panzer III. In addition, a new suspension and upper superstructure with sloped armor were also to be implemented. Work on the first few trial vehicles was to commence from March 1944, while the production would start in early 1945. In the end, by July 1944, the whole Panzer III/IV project was terminated. This vehicle simply did not offer that much of an improvement over a standard Panzer IV to warrant the introduction of a new vehicle.

The Anti-Tank Version Based on the Panzer III/IV

Interestingly, when the same tank commission met at the start of 1944, besides the talks about the Panzer III/IV, another project based on it was also proposed. This was to be an anti-tank version based on the Panzer III/IV chassis, designated at that simply as Jagdpanzer III/IV. This particular vehicle was heavily influenced by an earlier project based on the Panzer IV chassis. This project consisted of a Panzer IV chassis that was equipped with a new and well-sloped armor superstructure (known as Jagdpanzer IV). Initially, the Jagdpanzer IV was to be armed with the 7.5 cm L/70 gun. As this gun could not be produced in sufficient numbers, as a temporary solution, the shorter 7.5 cm L/48 gun had to be used instead until the production of the longer version could match up with the demand.

The Jagdpanzer III/IV project would incorporate many components that were already in production. This included the sloped superstructure, 7.5 cm L/70 tank gun, engine, etc. As these components were already available, the overall development time and costs could be greatly reduced. The only major modification was a completely redesigned suspension. Thus, the prospect of producing this vehicle did not seem a far-fetched idea. Given the German plans to cancel the overall Panzer IV production and instead focus on the anti-tank version based on it, great interest in this project arose. In addition, the Jagdpanzer IV’s general combat performance was deemed satisfactory, having excellent armor, low silhouette, and possessing sufficient firepower to deal with any Allied tank, further encouraging the Germans that another such vehicle was desirable.

In March 1944, Alkett received orders to prepare for the production of the first few trial vehicles meant to be used for testing. The German Army officials went to such an extent that, two months later, they informed Alkett and MIAG (Maschinenfabrik und Mühlenbau) that the StuG III production would cease in favor of the new Jagdpanzer III/IV project. The companies were to make the necessary preparations for the production of this vehicle, which was to commence in November 1944. During the first few months of 1945, three additional manufacturers, Krupp, Vomag, and Nibelungenwerke were also to be included in the Jagdpanzer III/IV production.

Name

Initially, the project was designated as Jagdpanzer III/IV. During the war, it was quite common for the Germans to change the designation for their vehicles, and the Jagdpanzer III/IV was no exception. In July 1944, Adolf Hitler insisted that the name of all Jagdpanzer IV should be changed to the much simpler Panzer IV lang (long). In addition, the capital letter of the manufacturer was also added to them, such as (A) for Alkett and (V) for Vomag. In the case of the now Panzer IV lang (E), the E stood for Einheitsfahrgestell (which could be translated as standard chassis). The name would eventually further be changed to the even simpler Panzer IV/70(E). This article will refer to it as such.

Design

Despite the Panzer IV/70(E) never being fully completed (no surviving photograph of its components exist), thanks to the fact that it would share most components with the Panzer IV/70(V), a somewhat clear picture of how its overall design may have looked can be considered.

The Hull

The Panzer IV/70(E) hull was likely quite similar to that of a Panzer IV. Given the introduction of new parts, for example, the transmission, there would be some changes made to incorporate them.

The front hull was redesigned and had a more sharply angled shape, with the glacis being placed at 60° and the lower hull at 45°. The transmission and steering brake inspection hatches appear to have been removed based on a few drawings of Panzer IV/70(E). The upper part of the hull, where the two steering brake inspection hatches were originally positioned, was slightly raised.

The Superstructure 

The Panzer IV/70(E) more or less had a superstructure directly copied from the Panzer IV/70(V). It was designed to provide the best possible protection with its angled and thick armor. The angled shape of the superstructure provided thicker effective armor and also increased the chance of deflecting enemy shots. Also, by using larger one-piece plates, it was much stronger and also easier to produce.

On the front angled plate, slightly to the right, was the gun with its mantlet. Next to it, on the right side, was a small round-shaped machine gun port. It was protected by a movable hemispherical-shaped armored cover. To the left of the gun was a small visor for the driver.

On the top part of the superstructure were two escape hatches. The right round-shaped one was for the loader. Left of it, the commander’s hatch had a small rotating periscope in the middle. The commander had a small additional hatch for the use of a retractable telescope. In front of the loader and commander hatches was a sliding armored cover for the gunsight. Additional periscopes with armored covers would likely have been added on the Panzer IV/70(E) superstructure’s roof.

Suspension

During the Panzer IV/70(E)’s development phase, it appears that a few different ideas for the suspension were proposed, though sources do not mention which precisely. In the end, German engineers decided to go with six 660 mm diameter road wheels. As rubber became a rare commodity in Germany in late 1944, these were instead steel-tired and internally sprung. It is not completely clear, but, according to T.L. Jentz and H.L. Doyle (Panzer Tracts No.20-1 Paper Panzers), these were suspended using simple leaf spring units. Author J. Ledwoch (Panzer IV/70), on the other hand, mentions that the leaf springs were replaced with horizontal volute springs.

The front-drive sprocket was taken from a Panzer III, and was modified to have center guides. The rear idler was taken from a Panzer IV, but provided with a strengthened and improved tensioning mechanism. The number of return rollers would likely have been reduced to three, as was common at that time. The Panzer IV track was replaced with completely new 540 mm wide tracks. This suspension was actually built and tested on some Nashorn vehicles, possibly during 1944.

The Engine and Transmission

The engine used on the Panzer IV/70(E) was the standard Maybach HL 120 TRM engine producing 265 hp@2,600 rpm. In the engine compartment, an additional 300 liters fuel tanks were to be placed. These would have greatly increased the vehicle’s operational combat range. Components such as the SSG 77 transmission, reinforced steering gear, and final drive was taken from the Panzer III Ausf.M. As no operational prototype was ever constructed and there is no information about the estimated weight, it is difficult to predict how the  Panzer IV/70(E) would have performed mobility-wise.

Armor Protection

The Panzer IV/70(E) glacis armor plate was 60 mm thick and placed at a 60° angle. The lower hull had the same thickness but was placed at a 45° angle. The upper superstructure frontal armor was 80 mm at a 50° angle. The sides were much weaker, being only 30 mm of armor placed at a 36° angle. The armor thickness of the remaining components of the Panzer IV/70(E) is not listed in the sources. Additional 5 mm thick armor plates were also provided for extra protection of the engine compartment sides.

The Panzer IV/70(E) could probably also be equipped with additional 5 mm thick armor skirts (Schürzen) covering the sides of the vehicle. These may have been replaced with the later developed stiff wire mesh panels (Thoma Schürzen).

Armament 

The main armament chosen for the Panzer IV/70(E) was the effective 7.5 cm StuK 42 L/70 gun. This gun was, more or less, the same one as used on the Panther tanks. While there is no information about its characteristics when mounted on the Panzer IV/70(E), these may have been close if not the same as on the Panzer IV/70(V). In that case, the elevation of the main gun would be –5° to +15° and the traverse 20°.  While not present on existing drawings, the use of a travel lock would be required due to the long and heavy gun. The muzzle brake would not be added to the gun, as it would create a lot of dust during firing.

As this gun required a large amount of room and the use of large one-piece ammunition, the Panzer IV/70(E) interior would have been very cramped and the ammunition capacity probably consisted of between 55 to 60 rounds.

The  7.5 cm StuK 42 L/70 could fire a few different types of rounds, including armor-piercing (PzGr 39/42 or 40/42), high-explosive (SpGr 42), and armor-piercing tungsten rounds. While the latter had a superb anti-armor penetration power, due to scarcity of tungsten, these rounds were rarely employed. Its cousin, the Panzer IV/70(V), usually carried 34 anti-armor rounds, while the remaining 21 were high-explosive rounds, so it is plausible that a similar ammunition load would also be employed on this vehicle.

When firing a standard armor-piercing round at a distance of some 500 m, it could penetrate 124 mm of armor placed at an angle of 30°. At 1 km and at the same angle, the armor penetration was 111 mm, and at 2 km it was 89 mm. Using the rare tungsten rounds, the armor penetration at 500 m at an angle of 30° was 174 mm. At ranges of up to 1 km, it could penetrate 149 mm of armor Thanks to this firepower this gun could effectively engage most Allied tanks up to the war’s end.

The secondary weapons would have consisted of an MG 42 machine gun, the crew’s personal weapons, and probably a Nahverteidigungswaffe (close defense weapon).

Crew

Four crew members would have been needed to effectively operate the  Panzer IV/70(E). These included the commander, gunner, loader/radio operator, and driver. The driver’s position was on the vehicle’s left front side, but his view of the surroundings was limited, as he only had a front-mounted periscope and a small periscope pointing to the right to see out of. Behind him was the gunner’s position, and behind him was the position of the commander. The last crew member was the loader, who was positioned on the vehicle’s right side. He operated the radio and he also doubled as the MG 42 machine gun operator.

The Fate of the Panzer IV/70(E) Project

In July 1944, Adolf Hitler insisted that production of the Panzer IV was to be terminated in February 1945 at the latest. Instead, the companies that were initially involved in the Panzer IV production were to focus on the Panzer IV/70 tank hunter. This included the (A), (V), and the newer (E) version.

In anticipation of the Panzer IV/70(E)’s production, work on its components was carried out during 1944. Due to the worsening economic situation, there were delays. Deutsche Edelstahl, which was responsible for the production of the armored components, reported that one superstructure was completed by September 1944. Some components that were to be used for this project were installed on a Nashorn for testing and evaluation.

The following month, in the hope of reducing the number of many different tank chassis, prioritizing mainly the Panther, Tiger, and the Panzer 38(t) chassis, this project came to an end. In contrast to the Panzer III/IV, some components for the Panzer IV/70(E) were built, but they were never assembled into a complete vehicle.

Conclusion

The Panzer IV/70(E), if ever produced, would have had good anti-tank firepower and protection. On the other hand, the introduction of one more design would have caused additional strain on the already stretched-to-the-breaking-point German industrial production capabilities. Its performance would likely have been quite similar to the Jagdpanzer IV, except for some improved mobility and a slight increase in ease of production, so there was really little reason to introduce it to service. While initially quite interested in the Panzer IV/70(E), this fact became quite obvious to the German military circles, who simply terminated the whole project even before a single prototype could be made.

Specifications
Crew	4 (Commander, Gunner, Loader/Radio Operator, and Driver)
Propulsion	Maybach HL 120 TRM 265 hp @ 2,600 rpm
Primary Armament	7.5 cm StuK 42 L/70
Secondary Armament	7.92 mm MG 42
Superstructure armor	80 mm, side 30 mm
Front hull armor	60 mm
Number built	One incomplete prototype

 

Sources

• K. Hjermstad (2000), Panzer IV Squadron/Signal Publication.
• T.L. Jentz and H.L. Doyle (2001)  Panzer Tracts No.20-1 Paper Panzers
• P. Chamberlain and H. Doyle (1978) Encyclopedia of German Tanks of World War Two – Revised Edition, Arms and Armor press.
• Walter J. Spielberger (1993). Panzer IV and its Variants, Schiffer Publishing Ltd.
• J. ledwoch (2002) Panzer IV/70, Militaria