Development of Hitler's Panzers was key to his early overwhelming victories in the East and West. The Panzer I light tank became Germany's first tank development after World War 1 and, though it was limited as a "true" tank in combat, set the foundation for things to come. The Panzer II light tank was developed as a stopgap measurement to help tie the existence of the Panzer Is to the upcoming Panzer III and Panzer IV. The Panzer III was designed to be capable of tangling with any known enemy tank head-on while the Panzer IV was initially developed as an infantry support vehicle. While dominating the field of play for some time, the Panzer III (like the Panzer I and II before it) suffered from being inadequately armed and armored and was eventually replaced by more modern and potent systems in the German arsenal - namely the improved forms of the Panzer IV, the Panther series and the Tiger series. The Panzer III saw service in the Polish, Czech, French and Low Countries campaigns as well as along the Eastern Front in Russia. After its inherent battlefield usefulness was past, the Panzer III chassis served in a handful of conversions, most notably, the StuG III assault gun.
Note: To help the reader along, it is important to note the German designation convention for its military vehicles. The abbreviation Pz.Kpf.W. covers "Panzerkampfwagen" and translates to "armored fighting vehicle". Likewise, the abbreviation Sd.Kfz. covers "Sonderkraftfahrzeug" and translates to "special motor vehicle". Ausf is the general term used to cover "model" or "mark" in showcasing a variant of note. Taking all this into account, the Panzer III can also be known by the designation of Pz.KpfW. III as well as Sd.Kfz. 141 while any model variants are covered in the convention of Ausf. A, Ausf. B, Ausf. C and so on. "Ausf." is the abbreviated form of the word "Ausfuhrung meaning simply "model" or "design".
In early 1934, the German Army Ordnance Department came to the agreement on the future of their armored corps. It was envisioned that the army would be made up of three companies composed of a light-class of medium tanks backed up by a fourth company composed of a dedicated class of medium tanks with better armor and firepower. The idea then was to develop two such medium tanks tasked with two distinct battlefield roles but were still complementary to the entire German process of waging a mobile land battle. The two tanks became the Pz.Kpf.W. III (Sd.Kfz. 141) and the heavier Pz.Kpf.W. IV medium tanks respectively. The Panzer III would be called to take on the role of tank killer - that is, square off against enemy armor at range - while the Panzer IV would be mainly an infantry support tank. German General Heinz Guderian laid down the specifications for the desired light-medium tank.
1935 saw prototype development contracts issued by the Weapons Department to Daimler-Benz, Krupp, MAN and Rheinmetall-Borsig. The new "light" medium tank would be armed with a more potent 37mm high-velocity main gun armament than her predecessors and supplemented by machine guns - two in the turret as co-axial mounts and a third in a flexible bow mount. The selection of the 37mm armament was a logistical one at this point for German infantry were already using the 37mm anti-tank gun (as the 3.7-cm PaK) in some number by this point. However, the decision to go with the 37mm main gun armament ran into some opposition from senior German officers (including Guderian) who believed that the new tank should be armed with a 50mm/5-cm main gun. As such, the compromise became the fitting of the 37mm gun for the time being, with a special turret ring made to accept a 50mm main gun in the future. The prototype vehicles were evaluated in 1936 with a 15-ton Daimler-Benz submission declared the winner.
The First Gun
The initial Panzer III armament centered around the high-velocity 3.7-cm Kw.K. L/45 main gun. The weapon was capable of firing armor-piercing (AP) and high-explosive (HE) rounds and proved most effective at close ranges where armor thickness of up to 70mm could be pierced. This value, however, dropped off dramatically at increased ranges. Projectile torque was accomplished through the internal rifling of the gun barrel - a standard practice of all German World War 2 tanks.
The Panzer III Ausf. A, Ausf. B, Ausf. C and Ausf. D
Daimler-Benz advanced its design and produced the Pz.Kpf.W. III Ausf. A. Power was supplied by a Maybach liquid-cooled gasoline engine of 250 horsepower output. The system featured five large-diameter road wheels to each track side with coil spring suspension. This suspension system was deemed inadequate by the German Army and, as such, further developmental models soon appeared in the Ausf. B, Ausf. C and Ausf. D, each fitting various suspension solutions (Ausf. D also fitted a revised cupola and thicker armor). These three further developments brought about use of eight small road wheels with leaf spring suspension. The hunt for the perfect suspension delayed all full-scale production of the Panzer III. Nevertheless, the German invasion of Poland began on Hitler's schedule, this being September 1st, 1939, with whatever Panzer Is, IIs and limited-quantity IIIs were on hand. A total of 75 Pz.Kpf.W. Ausf. A, Ausf B., Ausf. C and Ausf. D tanks were produced in whole.
Combat actions in Poland quickly showed the Panzer III Ausf. B, Ausf. C and Ausf. D to be insufficiently armored for the task at hand. Polish anti-tank guns could penetrate the 15mm-thick steel armor of these early Panzers with relative ease. Coupled with the suspension troubles, these Panzer IIIs faced early retirement and were eventually withdrawn from service before the Invasion of France in May of 1940. By that time, some 349 new Panzer IIIs would be made available to the Wehrmacht.
The Panzer III Ausf. E
The Pz.Kpf.W. III Ausf. E was developed around a new torsion bar suspension system for its new six road wheel layout (doubled on each track side for an actual total of 24 road wheels). After-action evaluation from engagements during the Polish campaign brought about an increase in armor protection to 30mm thickness along all major structural facings. While this worked well to increase crew and system protection, the added cost in weight increased to 21 tons. The increase led to the selection of a newer and more powerful Maybach powerplant now outputting 300 horsepower. The gun of choice was the 3.7-cm Kw.K. 36 L/46.5 series main gun (though later retrofitted with the 5-cm Kw.K. 38 L/42 series). The German Army Ordnance Office liked what it had and officially cleared the Pz.Kpf.W. Ausf. E for mass production. Ninety-six such vehicles were produced from 1938 through 1939.
The Panzer III Ausf. F
The Pz.Kpf.W. III Ausf. F was a slightly modified - though similar - version of the Ausf. E with six road wheels to a track side. Ausf. F featured the implementation of cast steel brake ventilation ducts and repositioned final drives along the front hull plate. The main gun was the 3.7cm Kw.K. 36 L/46.5 and (later) the 5-cm Kw.K. 38 L/42 series. The Pz.Kpf.W. III Ausf. F was produced in 435 examples from late 1939 through the mid-way point of 1940. Upon their inception into service, both the Ausf. E and the Ausf. F were the Panzer IIIs of choice for the Invasion of France.
The 5-cm Kw.K. L/42 (50mm) Main Gun
The original 37mm main gun armament proved inferior from the start, much to the chagrin on the part of senior German Army officials convinced of the type's inadequate power on the modern battlefield as it was. As such, the move to a more powerful 50mm gun was finally enacted with the selection and installation of the 5-cm Kw.K. 39 L/42. The 50mm gun was immediately a more capable component and could fire a broader range of projectiles over the 37mm system it replaced.
Despite its upgrade over the original 37mm guns, this 50mm system wasn't Hitler's first choice as the main armament for the new-model Pz.Kpf.W. IIIs (Hitler played a greater role in weapons development as the war progressed, often times to the detriment of the projects). In February of 1941, he explicitly stated that the Pz.Kpf.W. III be armed with the 5-cm Kw.K. 39 L/60, a gun barrel of higher velocity and longer length. The major problem with this requirement was that the Kw.K. 39 L/60 was in the short supply. Additionally, the Ordnance Department believed that their selection of the shorter-barrel 50mm was the right (and better) choice.
However, after the opening rounds that was the invasion of the Soviet Union (through Operation Barbarossa), Hitler was actually proven correct. 1,440 Panzer IIIs were fielded in the offensive and the 50mm-armed systems - though excellent against the light fast tanks of the Red Army -proved ineffective against the thickly-armored Soviet T-34 and KV-1 tanks, with reports of 50mm projectiles seemingly bouncing off Soviet turrets and hulls. Shortly thereafter, the longer higher-velocity 50mm gun barrel - the one originally endorsed by Hitler - became standard through the middle of production for the Pz.Kpf.W. III Ausf. J models. All other earlier Pz.Kpf.W. IIIs in circulation also had their main guns retrofitted as such. Conversions to the more lethal gun took place from the end of 1941 through 1943, producing some 2,000 more-capable Pz.Kpf.W. IIIs. By 1942, the old original 37mm main guns were all but non-existent across the war's ever-expanding fronts.
The Panzer III Ausf. G
The Ausf. G emerged from the Ausf. E and Ausf. F developments. Pz.Kpf.W. III Ausf. G fitted an all-new commander's cupola and a revised driver's vision block. Steel plates of 30mm thickness were added to the existing 30mm structure for vastly improved frontal armor protection and a more powerful engine was introduced to compensate for the added weight. The new steel plate additions proved so effective that they were retrofitted onto preceding Ausf. E and Ausf. F models. The main gun was the 5-cm Kw.K. 38 L/42 series while the second 7.92mm co-axial machine gun was dropped from the turret design. The Ausf. G was produced in 600 examples from early 1940 into 1941. The Ausf. G fought in limited quantity in the invasion of France.
The Panzer III Ausf. H
The Pz.Kpf.W. III Ausf. H was produced in 308 examples with the 5-cm Kw.K 38 L/42 main gun. Production began in October of 1940 and lasted into April of 1941. Bolt-on armor brought total frontal armor thickness to 60mm (30mm inherent + 30mm bolt-on) and wider tracks helped its ground control.
The Panzer III Ausf. J
The Ausf. J began service in March of 1942 and came from various factories with base 50mm armor thickness. To this, the Germans used add-on armor of an additional 20mm thickness across the major forward-facing surfaces (including the gun mantlet). Power was derived from a single Maybach HL 120 TRM V-12 gasoline-powered, water-cooled engine of 300 horsepower. Maximum road speed was 25 miles per hour though this decreased substantially to 12 miles per hour when off-road. Range was listed at 85 miles on road and decreased to 55 miles off-road. The hull was further lengthened and 482 examples were produced in 1941. A second batch of Pz.Kpf.W. III Ausf. J models later appeared in 1,067 examples from late 1941 into the middle of 1942, now with the longer and more powerful 5-cm Kw.K. 39 L/60 main gun. Likewise, the Ausf. G, Ausf. E and Ausf. F models were also retrofitted with the newer 50mm main gun when possible.
The Panzer III Ausf. K
The Ausf. K was the Panzerbefehlswagen command tank. This version sported a new modified turret though it retained its full combat armament.
The Panzer III Ausf. L
The Ausf. L was similar to the Ausf. J production model. The Ausf. L featured the long-barrel 50mm main gun and was produced in 653 examples during the middle and latter half of 1942. Additional armor came in the form of 20mm bolt-on armor plating on top of the pre-existing 50mm armor. Operating weight hovered around 24.2 tons, nearly twice the weight of the initial Panzer III. Production was once again spread out to a variety of German firms to help facilitate the numbers needed to wage Hitler's war. Ausf. L models were also the first Panzer IIIs to make use of spaced armor skirts to improve protection of the hull and turret sides. Ausf. L models were fielded by Rommel across his North Africa campaigns. These African Panzer IIIs proved highly effective against the early armor of the British. They were modified with tropical kits to extend their capabilities in the hot dry desert climates, outclassing the lighter Allied tanks through sheer firepower and were able to outmaneuver the larger (and heavier) Allied infantry tanks through speed.
The Panzer III Ausf. M
The Pz.Kpf.W. III Ausf. M became the final true Panzer III production model. These systems grossed over 22 tons and were also armed with the long-barrel 50mm main gun. Other changes included the implementation of a deep-wading exhaust stack for some amphibious capability. Production was undertaken from late 1942 into the beginning of 1943 to which some 250 examples were rolled out.
The Ausf. M was powered by a single Maybach HL 120 TRM 12-cylinder gasoline engine developing 300 horsepower. Top speed was 25 miles per hour while range was limited to 110 miles. Fording was possible up to 2 feet, 8 inches and gradients of up to 60 percent fell under the Panzer IIIs treads. The tank could scale a vertical obstacle of up to 2 feet and cross over trenches 8 feet, 6 inches deep.
End of the Line: The Panzer III Ausf. N
The Pz.Kpf.W. III Ausf. N appeared when the combat usefulness of the Panzer III had met it last days. The idea was to fit a larger main gun to give the system greater firepower against the new classes of armor, particularly along the East Front in Russia. While attempts to fit a long-barrel 75mm gun and an all-new turret came to naught (the chassis simply wasn't up to the task), the low-velocity 7.5-cm Kw.K. L/24 gun seemed to fit the bill. This 75mm main gun was the same type as fitted on the Panzer IV medium tanks and proved effective enough, but in actuality, was inferior to the 50mm L/60 it replaced. Panzer IIIs with this new gun armament were designated as the Ausf. N and production began in June of 1942. When production ended in August of 1943, some 700 Ausf. N models were in circulation with the German Army. Previous Panzer III models - namely the more-capable Ausf. J, Ausf. L and Ausf. M models - were retrofitted with the 75mm main gun and placed back into circulation when possible.
From then on, the Panzer III served to support the larger and more powerful Tiger series. The end of the line for the Panzer III had officially come, but not before securing a solid legacy in service with the German Army. Production of the Panzer III lasted into August of 1943, by which time the writing for the tank as a frontline combat system were on the wall. By late 1943, nearly all frontline Panzer IIIs had been replaced by Panzer IVs. Some Panzer IIIs were still in service at Normandy and Arnhem during 1944. The Panzer IIIs frontline duty ended after combat actions in the Battle of Kursk.
Some 15,000 Panzer III chassis were produced and used as both tanks and a line of alternative battlefield vehicles.
Like the Panzer II, the Panzer III was envisioned as an amphibious tank to take part in beach landings during Operation Sea Lion - the inevitable invasion of the British mainland. Though the invasion was ultimately (and indefinitely) postponed by Hitler after the Battle of Britain, the design was completed and used in a limited role along the East Front in 1941.
The Gepanzerte Selbstahrlafette fur Sturmgeschutz 7.5-cm Kanone (Sd.Kfz. 142 and also known simply and more commonly as "Sturmgeschutz III" or "StuG III") became a 75mm mobile turretless assault gun utilizing the chassis of the Panzer III. The StuG III became Germany's most-produced armored fighting vehicle and tank destroyer of the war. Some were made available for the invasion of France in May of 1940 and many saw service through to the end of the war.
The Panzerbeobachtungswagen became an armored observation vehicle while the Panzerbefehlswagen III was a command vehicle. The Panzer III was converted into a flamethrowing tank, these systems known collectively as "Flammpanzers". Some Panzer III turrets found their way as static gun emplacements along the Atlantic Wall to protect against an Allied land invasion from the West and, in some case, as protective insurance across Italy from an Allied invasion to the South.
The Russians, desperate to make anything out of something, used captured Panzer IIIs and converted them into their 76mm turretless Su-76i assault guns - these used to good effect against their former masters.
Panzer III Walk-Around
For this particular example, it is assumed one is observing a Pz.Kpf.W. III Ausf. F model of 1939. The tank maintained a rather modern look when compared to the earlier Panzer types. Six small road wheels were fitted to a track side with applicable suspension. Three track return rollers were situated along the upper part of the tread while the drive sprocket was located at the front and the idler at the rear. The hull featured sloped and straight-facing armor as did the superstructure. The turret was fitted in the forward center of the superstructure and sported the initial main gun armament of 37mm. The crew compartment was separated from the liquid-cooled gasoline engine via a bulkhead and both hull side panels (within the track area) sported crew escape hatches.
Crew accommodations were somewhat conventional and featured a driver, radioman, gunner, loader and commander. The driver sat in the forward hull offset to left while the radioman sat to his right. Driver controls were a series of levers as well as foot pedals with vision through a forward vision port protected by laminated glass. When the tank was "buttoned" down, driving would be accomplished via an episcope that was moved into place. Off to his left shoulder was another vision port with a removable glass block. The radio operator manned the wireless radio control station as well as a 7.92mm bow-mounted machine gun (a common armament practice among World War 2 tank designs since dropped in the Cold War). Aiming was through a telescopic eyepiece and ball mounting with limited traverse. The radioman merely moved his head about the connected headrest to train the machine gun on a target. A pistol port was located to his immediate right in an attempt to handle close-range infantry trying to rush the tank with grenades. Entry and exit for the driver and radioman was via two separate forward hinged hatches along the top of the glacis plate.
The gunner, loader and commander were located in the traversing turret with the main armament. The commander had easy access to the cupola and top-mounted turret hatch as well as vision blocks at all angles. The turret cupola hatch was fitted to the aft portion of the turret and was made up of two semi-circle steel panels hinged to the sides. The turret featured no floor and, as such, the commander and gunner were suspended while the loader would remaining standing, having to adjust his stance with every turn of the turret (a turret "basket" was later introduced). The loader took a position to the right-hand side of the gun and had access to a vision block and turret entry/exit hatch as well as an auxiliary turret traverse hand wheel (which, when used in conjunction with the primary handle operated by the gunner, could help the turret react in a quicker fashion). The gunner manned a position forward and to the left in the turret, left of the main gun. He aimed and fired the main gun as well as operated a pair of 7.92mm co-axially-mounted machine guns. The main gun was electrically-fired while the machine guns activated through a foot-actuated switch. The turret was manually-traversed via a hand wheel by the gunner.
To that end, the Panzer III did much in those early invasions of Europe and fell well into the German army philosophy built on speed and overwhelming tactics. Each new Panzer development seemed to ratchet up the stakes and the Panzer III was no exception. Its sheer production volume ensured that it would maintain a face on the battlefields of World War 2 for years and its adaptability proved this correct. Some 5,774 Panzer III tanks were ultimately produced.