Panzer III Nazi Tank.

Panzerkampfwagen III - PzKpfw III Ausf L

Panzer III is the common name of a medium tank that was developed in the 1930s by Nazi Germany and used extensively in World War II. The official German designation was Panzerkampfwagen III (abbreviated PzKpfw III). It was intended to fight other armoured fighting vehicles and serve alongside the infantry-support Panzer IV. However, it soon became obsolete in this role and for most purposes was supplanted by up-gunned Panzer IVs, though some Panzer IIIs would continue to be used for infantry support until late in the war.

Development history

On January 11, 1934, following specifications laid down by Heinz Guderian, the Army Weapons Department drew up plans for a medium tank with a maximum weight of 24,000 kg and a top speed of 35 km/h. It was intended as the main tank of the German Panzer divisions, capable of engaging and destroying opposing tank forces.

Daimler-Benz, Krupp, MAN, and Rheinmetall all produced prototypes. Testing of the prototypes took place in 1936 and 1937, leading to the Daimler-Benz design being chosen for production. The first Panzer III A came off the assembly line in May of 1937, and a total of ten, two of which were unarmed, were produced in 1937. Mass production of the tank, then in model III F, began in 1939.

Between 1937 and 1940, attempts were made to standardize parts between Krupp's Panzer IV and Daimler-Benz's Panzer III.

Much of the early development work on the Panzer III was a quest for a suitable suspension. Several varieties of leaf-spring suspensions were tried on Ausf A through D before the torsion-bar suspension of the Ausf E was standardized. The Panzer III, along with the Soviet KV heavy tank, was one of the first tanks to use this suspension design.

The Panzer III was intended as the main battle tank of the German forces. It outclassed most of the tanks of the time However, when it initially met the Soviet KV and T-34 tank designs it proved to be inferior. To meet the growing need to counter the T-34 the Panzer III was upgunned with the 50mm KwK 39 L/60 and received more armor which made it a very formidable opponent for the T-34. This still failed to address the problem caused by the KV tanks though, so in 1942, several self propelled guns as well as the longer barreled 75mm Kwk 40 L/43 Panzer IV Ausf F2 and the Panzer IV Ausf G were developed and produced.

In 1942, the Ausf N model of the Panzer III was created with an L/24 75 mm gun, a low-velocity gun designed for anti-infantry and close-support work. For defensive purposes however, it did carry a few rounds of hollow charge ammunition which could penetrate 70-100mm of armor depending on the round's variant but these were strictly used for self-defensive purposes.

Armor

The Panzer III A through C had 15 mm of slightly sloped homogeneous steel armor on all sides, with 10 mm on the top and 5 mm on the bottom. This was quickly determined to be insufficient, and was upgraded to 30 mm in the D, E, F, and G models, with the H model having a second 30 mm layer of face-hardened steel applied to the front and rear hull. The J model had a solid 50 mm plate on the front and rear, while the late J, L, M, models had an additional layer of 20 mm of armor on the front hull. This additional frontal armor meant the Panzer III during 1941 and 1942 was impervious to most British and Russian anti-tank guns at all but close ranges when shot at from the front. The sides were still vulnerable to many enemy weapons including anti-tank rifles.

The unusually heavy rear armor of the Panzer III was a weight penalty that was not commensurate with its combat value. Although several tanks of the early war period had heavy rear armor, in general the design trend during the war was to thin the side and rear armor as much as possible, concentrating heavy armor in the frontal quadrant. For example, the Panther tank had very heavy frontal armor but thin side and rear armor.

Armament

A Panzer III during the North African campaign of World War II.

The Panzer III was intended to fight other tanks and a high-velocity 5 cm gun was initially called for. But the infantry were being equipped with the 3.7 cm anti-tank gun, and it was felt that in the interest of standardisation the tanks should carry the same. As a compromise, the turret ring was made large enough to accommodate a 50 mm gun should a future upgrade be required. This single decision would later assure the Panzer III a much prolonged life in the German army.

The early models (Ausf A to Ausf E, and a few Ausf F) were equipped with a short barrelled 3.7 cm KwK 36 L/46.5 which proved somewhat satisfactory during the campaigns of 1939 and 1940 but later models (Ausf F to Ausf M) were upgraded with the heavier 5 cm KwK 38 L/42 and 5 cm KwK 39 L/60 guns in response to increasingly better armed and armoured opponents.

By 1942, it was decided to change the Panzer IV into Germany's main medium tank because of its impressive fire power and its stablemate the Panzer III was to continue production as a support vehicle. The Ausf N model mounted a low-velocity 7.5 cm KwK 37 L/24 gun - the same gun used by the early models of the Panzer IV. This tank was used for infantry support as a replacement for the StuG III assault gun, which was by then mainly used as tank destroyer.

All early models up to and including the Ausf F had two 7.92 mm Maschinengewehr 34 machine guns mounted coaxially with the main gun, and a 7.92 mm MG34 in the hull. Models from the ausf G and later had a single coaxial MG34 and the hull MG34.

Mobility

The Panzer III models A through C were powered by a 230 hp, 12-cylinder Maybach HL 108 TR engine, giving a top speed of 32 km/h (20 mph) and a range of 150 km (95 mi). All later models were powered by the 320 hp, 12-cylinder Maybach HL 120 TRM engine. Top speed varied among models, depending on the transmission, armor, and gun, but was around 40 km/h (25 mph). The range was generally around 150 km (95 mi).

Combat usage

The Panzer III was used in the campaigns against Poland, France, the Soviet Union and in North Africa. Some were still in use in Normandy and Arnhem in 1944.

In the Polish and French campaigns, the Panzer III formed a small part of the German armored forces. Only a few hundred ausf A through F were available in these campaigns, most armed with the 37 mm gun. They were the best medium tank available to the Germans and outclassed most of their opponents such as the Polish 7TP, French R-35 and H-35 light tanks.

By the time of the German invasion of the Soviet Union (Operation Barbarossa), the Panzer III was numerically the most important German tank. By this time the majority of the available tanks (including re-armed ausf E and F, plus new ausf G and H models) had the L/42 50 mm gun. The tanks used in North Africa also had the 50 mm L/42. The Panzer III was initially outclassed by the Soviet T-34 and KV tanks in 1941 before the upgrade to the longer 50mm gun. However, most of the Soviet tank units were mainly composed of the much lighter-armed and armored such as the T-26 and BT tanks. This, along with superior German tactical skill, crew training, and the good ergonomics of the Panzer III all contributed to a rough 6:1 favorable kill ratio for German tanks of all types in 1941.

With the appearance of the T-34, rearming the Panzer III with a more powerful L/60 50 mm gun was prioritized. The ausf J and L versions had this longer gun, thicker armor, and some simplified features. These versions were available throughout 1942 and into 1943. In addition, to counter Soviet antitank rifles as well as Hollow charge attacks, in 1943 the ausf M version began the use of spaced armor skirts ("schurzen") around the turret and on the hull sides. By then, however, the Panzer III was beginning to be relegated to secondary roles, and it was replaced as the main German medium tank by the Panzer IV and Panther. The final version, ausf N, mounted a short 75 mm howitzer for use in Infantry support.

The Panzer III was well-designed in that it had a three-man turret crew (gunner, loader and commander), leaving the commander free to concentrate on commanding the tank and maintaining situational awareness. Although other medium tanks of the time also had this feature, most tanks of the late 1930s had fewer than three men in the turret crew. These other tanks, which may look impressive on paper, lacked this key element of "fightability". The French Somua S-35 was a classic example of a tank that appeared to be the equal of the Panzer III on paper, with a good gun and strong armor, but with its one-man turret crew it was hopelessly outclassed by the Panzer III.

The Panzer III chassis was the basis for the Sturmgeschutz III assault gun, probably the most important German self-propelled gun of the war.

Variants

• Panzer III Ausf A, B, C, D - pre-production models in 1937-1938. 75 produced.
• Panzer III Ausf E, F - Production models 1939-1940. Armed with 3.7 cm KwK 36 L/46.5 (later 5 cm KwK 38 L/42) guns. 531 produced.
• Panzer III Ausf G - More armour on gun mantlet. Armed with 5 cm KwK 38 L/42 gun. 600 produced in 1940-1941.
• Panzer III Ausf H - Minor modifications. Bolt-on armor added to front hull (30 mm + 30 mm plates). 308 produced in 1940-1941.
• Panzer III Ausf J - The hull was lengthened. Front armor modified again (50 mm single plate). 482 produced in 1941
• Panzer III Ausf J/1 - longer/more effective 5 cm KwK 39 L/60 gun. 1067 produced in late 1941 to mid 1942.
• Panzer III Ausf L - Uparmored to 50 mm + 20 mm plates. 653 produced in 1942.
• Panzer III Ausf M - Minor modifications such as deep-wading exhaust and schurzen; 250 produced in 1942-1943.
• Panzer III Ausf N - Armed with a 7.5 cm KwK 37 L/24 gun. 700 re-equipped J/L/M models in 1942-1943.

Designs based on chassis

• Tauchpanzer III - Some tanks were converted to "diving tanks" for Operation Sealion.
• Panzerbefehlswagen III - Command tank. Heavier armor, dummy gun, and long-range radios.
• Artillerie-Panzerbeobachtungswagen III - Forward artillery observer tank. 262 produced.
• Flammpanzer III Ausf M/Panzer III (F1) - Flamethrower tank. 100 converted from existing Panzer III M.
• Bergepanzer III - In 1944 some Panzer IIIs were converted to armoured recovery vehicles.
• Sturmgeschütz III - Assault gun with 75 mm StuK.

The Soviet SU-76i self-propelled gun was based on captured German Pz Kpfw III and StuG III chassis. About 1,200 of these vehicles were converted for Red Army service by adding an enclosed superstructure and ZiS-5 76.2 mm gun.