The German workhorse: Panzer IV

A quick question: which tanks do you think are most iconic of the various combatant nations in World War II? America's best-known tank is clearly the Sherman, and the Soviet Union is well-represented by the T-34. But what about Germany? Most people would probably think of the mighty Tiger or the advanced Panther, but the humble Panzer IV is arguably more representative of Germany's tank forces in the war. The Panzer IV was the most highly produced German tank with around 8,500 made, and the only German tank in continuous production from before the war to its very end.
The Versailles Treaty that ended World War I forbade Germany from establishing a tank force. Once Hitler came to power in 1934 (Read our earlier article – Becoming Führer), he embarked on an aggressive development campaign, initially in secret but later in the open, to remedy Germany's lack of armor.

English sources usually refer to German tanks from the era as Panzer, but that word needs some explanation. It literally means "armor," but it's actually an abbreviation of Panzerkampfwagen, literally "armored combat vehicle," the German word for a tank. Early in their development cycle, when the tank project was still a secret, various tank designs also received names designed to mislead other nations, such as "Neubaufahrzeug," "new construction vehicle," or the Panzer IV's codename, "Begleitwagen," "escort vehicle." Additionally, they could also be referred to as "Sd.Kfz." and a three-digit number, which was the ordnance directory designation. The letters stood for "Sonderkraftfahrzeug," "special purpose vehicle," and the numbers identified the specific design, which could be anything from a half-track through a tank, a tank destroyer, a self-propelled artillery piece, a recon vehicle, a truck, a mine-clearing vehicle or something else.
 
Nazi Germany's first two tanks were really more of a learning effort than viable war machines for World War II. The Panzer I light tank had no cannon at all, and was only armed with a pair of machine guns. The Panzer II had a 20 mm autocannon and a machine gun. The next two tanks, the Panzer III and IV medium tanks, were meant to be the real deal, and were designed to operate together, each focused on a different goal. The Panzer III, at least its first version, had a 3.7 cm gun as its main armament, and was intended to destroy enemy tanks. The Panzer IV had a short-barreled, howitzer-like 7.5 cm gun, the Kwk 37, designed to primarily fire high explosive shells against soft targets, anti-tank positions and fortified infantry.

The two tanks and their predecessor models were meant to be used as a team. Panzer Is, IIs and IIIs would form a wedge with the Panzer IIIs at its tip and the older models on the sides. On the attack, they would take out tanks and light targets, and would mark anything they couldn't tackle with tracer rounds or smoke grenades. The Panzer IVs would then roll up behind the wedge and destroy those targets.
 
One noteworthy innovation of the Panzer III and IV, not unique but quite rare at the time, was the use of a 5-man crew. Most tanks before World War II had smaller crews, who had to divide their attention between various tasks; the commander, for example, also had to aim and load the gun, which distracted him from observing the tactical situation. The larger German crew allowed everyone to focus on a single task, greatly increasing the tank's effectiveness in combat.

Another design feature that improved crew efficiency was the commander's cupola, a cylindrical protrusion on top of the turret. It had vision slits in its side, giving the commander 360° vision around the tank by simply sticking his head up there. In contrast, the commander's periscope in the Sherman only allowed the commander to see in one direction at a time. If he wanted a better overview of his tactical surroundings, he had to open the hatch and pop outside, exposing himself to enemy fire.

The two medium Panzers had their debut in September 1939 with the invasion of Poland, the event that started World War II. Their first taste of combat gave the Germans two surprises, one pleasant, the other not so much. They found that while the Panzer IV was not designed to engage armored targets, its gun was still powerful enough to do so with reasonably good effect. The unpleasant surprise was that the armor on these early German tanks (8 to 16 mm [0.3 to 0.6 in] on the Panzer IV) might as well have been made of paper. It was sufficient against small arms fire or shrapnel from artillery shells, but practically any anti-armor weapon could punch through it easily.

The invasion of France in May 1940 reinforced the lesson about the thin armor, but also provided a new one about guns. While the Panzer III and IV had enough firepower against Polish vehicles, their guns were inefficient against the heavier types of French and British tanks.
 
The panzer IV underwent small, gradual improvements over several steps as the war progressed. From Ausf. A through Ausf. B, C, D, E and F, it got more powerful engines, more and more armor (up to 50 mm [2 in] on some surfaces of the Ausf. F), and a range of other small changes. ("Ausf." is short for "Ausführung," "version.")

As mentioned before, the insufficiency of both the Panzer III's and IV's guns against heavily armored enemies was noted in France. A more powerful gun was necessarily a larger gun, and the Panzer III just wasn't large enough to fit one. The Panzer IV had a wider turret ring and a larger turret, big enough for a heavier cannon. It was decided that the tank would discard its original purpose as a support weapon and take over the Panzer III's role as a tank fighting other tanks.
 
In May 1941, a few weeks before Operation Barbarossa, the invasion of the Soviet Union, Hitler gave the order to upgrade the Panzer IV with better armament. The first gun of choice was the 5cm Pak 38 anti-tank gun which had already entered service the previous year. Barbarossa, however, quickly overruled that idea. The first few months of combat shocked the Germans: not only was the Soviet KV-1 heavy tank safe from the Panzer IV's original gun, but so was the T-34 medium tank, which the Panzer IV was supposed to be at parity with. It was clear that the Pak 38 was not going to be enough; something much stronger was required.

That stronger gun ended up being the KwK 40. It had the same 75 mm muzzle caliber as the old gun, but its longer barrel allowed it to fire shells at much higher velocities, increasing penetrating power. At first, the gun was mounted on already existing Ausf. F-s, but the next upgrade of the Panzer IV, the Ausf. G, came with the new gun as default. The Ausf. G also had even more additional armor, with 80 mm (3.15 in) of steel in the front, comparable to the frontal armor on most versions of the Sherman. When it first appeared on the battlefields in 1942, the Ausf. G could reasonably expect to penetrate the armor of any Soviet or Western Allied tank from a range of roughly 1,000 m (1090 yd).

With new versions of the Panzer IV being heavier due to more armor and a larger cannon, the relatively narrow tracks of the vehicle became more and more liable to sink into soft terrain, a problem the Sherman also had. The tracks of the Ausf. F were slightly widened for a better weight distribution, and "ice sprags" not unlike the Sherman's duckbill extension could be added for even more contact surface.

In 1943, a new modification started appearing on Panzer IVs: the Schürzen (“aprons”) skirts. These were thin metal plates protecting the sides of the hull and the turret, with some empty space between them and the "real" armor. Popular culture often claims that these skirts were developed as a defense against the bazooka (Read our earlier article – The Bazooka) and other shaped-charge warheads, but this is not actually true. The skirts were invented as protection against light anti-tank weapons, more specifically Soviet anti-tank rifles. The idea behind the invention was not to stop the incoming projectile cold, but to destabilize it. The round would punch through the skirt with no problems, but it would then cross the empty space behind the skirt tumbling, rather than flying straight – and the tumbling shot would not go through the actual armor. This was, in fact, an early application of the principle of spaced armor, which still sees heavy use in present-day tank designs. The Schürzen also served well against some other anti-tank weapons, such as the British PIAT, but not against the bazooka. The fighting in the hedgerows of Normandy after D-Day also showed that heavy vegetation could pull the side skirts off the tank, as they were not attached securely enough.

The next Panzer IV upgrade, the Ausf. H, included further gradual refinements, and the addition of the Zimmerit coating. Zimmerit was a paste that could be applied to a tank's outside surfaces either in the factory or in the field, and given a distinctive notched texture with a trowel or whatever was at hand. Its purpose was to protect tanks against magnetic mines, which the Germans considered to be a serious threat. A sufficiently thick layer of pretty much any non-ferromagnetic substance would prevent such a mine from sticking to the tank, and the ridged surface of the coating made it even harder to stick a mine there. As a welcome side effect, the coating also served as a good base for camouflage paintjobs. Zimmerit was applied to a variety of German tanks, but it's one of the distinguishing features of the Ausf. H.

The Ausf. G and H represented the height of the Panzer IV's career, but they also hallmarked its design limitations: all the extra armor and the heavier gun was putting a lot of stress on the tank's suspension system and impacted its mobility. This was as far as the design could be taken.

After its long series of upgrades, the Panzer IV became a very good tank, but good tanks alone don't win wars. By 1944, Germany was clearly on the back foot and fighting a losing battle. A late-version Panzer IV was a serious threat to the ubiquitous Sherman, but the German war industry, heavily damaged by Allied heavy bombers and starved for resources, just couldn't manufacture as many tanks or spare parts as the Allied war machine. The last version of the Panzer IV, the Ausf. J, was introduced in late 1944 in an attempt to simplify the design and make it cheaper and quicker to produce.
 
The Ausf. J was cheaper and quicker to build, but it was also a step backward in terms of quality. Many Ausf. J-s came without the Zimmerit coating, and the original solid Schürzen side skirts were replaced with a wire mesh version. The biggest step backward was the removal of the electric generator that powered the turret's traverse, forcing crews to rotate the turret manually and at a much slower speed. As with other German attempts at producing extremely cheap weapons late in the war, this too was a desperate and unsuccessful attempt to stave off the Nazi regime's inevitable defeat.

Unlike the regime, the Panzer survived the war, at least in some countries. Spain continued to use the tank into the 50s, and sold 17 of them to Syria in 1967. Syria also acquired another roughly 60 Panzer IVs from other European countries, and used them in its armed conflicts with Israel. Interestingly, some of these tanks participated in the Six-Day War in 1967, where they met their old enemy, the Sherman, upgraded versions of which were used by Israel.

Like the Sherman, the Panzer IV was also used as the base for a variety of modifications and new vehicles. The Sturmgeschütz (StuG) IV was an assault gun closely related to the famous StuG III: it was the StuG III's casemate and gun mounted atop a Panzer IV body. The Jagdpanzer IV was another turretless vehicle, a self-propelled anti-tank gun, also based on the Panzer IV, and arguably the best German weapon of its type.

The Panzerbefehlswagen IV ("armored command vehicle") was a command version of the tank, equipped with powerful radios and related electrical equipment, capable of coordinating artillery support, infantry and air strikes. The Sturmpanzer IV, nicknamed "Brummbär" by Allied intelligence, was an infantry support weapon with a short but massive 105 mm (5.91 in) gun. The Panzer IV also served as the base for several anti-aircraft vehicles, including the Wirbelwind ("whirlwind") armed with quadruple anti-aircraft guns, and the Ostwind ("east wind") with a single 37 mm anti-aircraft cannon.

Other Panzer IV modifications include artillery and anti-tank vehicles, the Bergepanzer IV recovery vehicle, and bridgelayers. The Munitionsschlepper für Karlgerät ("munitions carrier for Karl-device") was, as the name suggests, an ammunition carrier for the giant Karl-Gerät siege mortar, also based on the Panzer IV. What makes carrying ammunition impressive is that each shell weighed 2 tons, and the carrier vehicle could carry five of these simultaneously: one at the end of a crane and another four in a special compartment.
 
If you want to see a real Panzer IV, join us on our tours which either visit the Bovington Tank Museum in the United Kingdom or Bastogne Barracks in Belgium.