Panzer III

The Panzer III (Panzerkampfwagen III) was originally intended to serve in a companion role with Panzer IV, it dealing with enemy armour while the Panzer IV served as an infantry support tank. Wartime experience totally inverted this scheme.

The Panzer III was the most numerous German tank in the early months of the Soviet campaign and its inadequacies quickly became apparent. Upgrading its armament to the 50mm L/60 in early 1942 gave it some usefulness against the T-34 at close ranges but the Panzer IV, which was bigger and had a larger turret ring, proved more adaptable to upgrading and better fitted to take over the role of Germany's main battle tank. The final version of Panzer III had a low-velocity 75mm gun and was intended to serve the infantry support role that had originally been cast for the Panzer IV. Production of all types ended in 1943 but its chassis was the basis for the StuG III assault gun, one of the most successful of all German designs and the most numerous. The Panzer III marked several key innovations. It was the first German design to use a 3-man turret, a critical improvement eventually copied by all combatants, and the first to use an intercom.

Development
The Panzerkampfwagen III medium tank, or the Panzer III was developed in the 1930s. Starting in early 1934, Heinz Guderian set down some specifications for a new tank, which Army Weapons Department took up to design the tank to weigh no more than 24,000 kilograms with a top speed of 35 km per hour. This tank's role was to be the main tank of the German army and was expected to destroy opposing tanks, as opposed as a tank made to destroy anti-tank guns and opposing infantrymen, which the Panzer IV took up in.

Damlier-Benz, Krupp, MAN, and Rheinmetall produced prototypes meeting the specifications and the Damlier-Benz model was chosen after testing in 1936-1937. The Panzer III model used a leaf-spring suspension in its early models (Ausf. A - Ausf. D) before utilizing a six-wheeled torsion-bar suspension in the Ausf. E and beyond. The Panzer III had a crew of five people, the commander, gunner, loader, driver, and assistant driver. The best feature of the Panzer III during its introduction that is the most overlooked was the three-man turret, which was not as common at the time. This frees the commander to be able to effectively command the tank while maintaining situational awareness rather than be burdened by the role of a loader or gunner, improving combat effectiveness of the tank. Despite this rather advance design, the turret did not have a turret basket for the crew. It was a proven design and production began in May 1937. The total number of Panzer IIIs tanks constructed in its production life was 5,774 units (excluding StuG III variant).

Combat Usage
During the intial stages of World War II, the Panzer III was only a fraction of the total German armored forces, with only about a hundred Ausf. A to F available in the Polish and French campaigns. Despite that, they were the best tanks at the time an outclassed the tanks fielded by these country, which were mostly light tanks. Although trouble with some French medium and heavy tanks prompted to upgun the Panzer III from 37 mm to a 50 mm cannon, but the battles ended before the programs were implemented. By Operation Barbarossa, the Panzer III was the numerical superior tank in German forces. Though capable against the Soviet light tanks T-26 and BT series, it found itself outgunned by the Soviet T-34 and KV-1 tanks.

The appearance of better and more heavily armored tanks showed that the Panzer III needed an upgrade, and so the Panzer III was mounted with a 50 mm KwK 38 cannon, the first to be mounted with said gun was designated the Panzer III Ausf. F.

The Panzer III Ausf. F was first prompted by the German army concerns of their tank-killing tank being undergunned during the French campaign, where the appearance of the French Char B1 and British Matilda tanks proved that their current arsenal was inadequate to counter these threats. Though it was initiated during the campaign, it was over before it could be fully implemented among the armored forces. It wasn't until Operation Barbarossa, where the appearance of the Soviet T-34 and KV-1 tanks forced the Germans to take up better weapons for their anti-tank inventory. The solution was the 50 mm KwK 38, which helped the Panzer III be able to destroy these Soviet tanks with APCR rounds. Even though the newer Soviet tanks may put the Panzer III out of frontline duties, it still stayed as the more common Soviet T-26 and BT series light tanks were more easily destroyed by the Panzer III.

The German army continued to upgrade their Panzer III to keep them in service as long as possible. The Panzer III Ausf. H featured another 30 mm of armor applied to the original 30 mm of armor on the hull. The next significant upgrade was to the Panzer III Ausf. J, which featured a solid 50 mm of frontal and rear armor plating.

The Panzer III Ausf. J gave the German army better armor for their Panzer III and with a better gun. However, it was still considered undergunned to the Soviet contemporary T-34 and KV-1 tanks as the 50 mm KwK 38 was not powerful enough to penetrate these tanks frontally with normal ammo. This requires the use of APCR, which was in low supply. The Soviet T-26 and BT series light tanks were still easily taken care of and were still in larger quantities than the T-34s and KVs, but T-34 production was kicking off and it won't be long before the T-34 becomes the main tank of the Red Army.

The Panzer III still needed improvements if it ever was to go up against the more modern tanks and Germany needed it to stay in service as long as possible as their new tanks are being developed. The next variant featured additional armor and a better 50 mm cannon, the 50 mm KwK 39, on the Panzer III Ausf. J1. The armor had an additional 20 mm offset armor in the front hull and turret, plus the 50 mm KwK 39 featured a longer barrel than the 50 mm KwK 38, increasing its penetration values.

The Panzer III J1 was only a stopgap design to integrate the 50 mm KwK 39 into service as fast as possible. The final designs in its later models were later redesignated the Panzer III Ausf. L.

The Panzer III at this time was given one more upgrade in its armor into the variant Panzer III Ausf. M, which featured the new Schürzen armor skirts.

Despite its newer aspects compared to older Panzer IIIs, the prevalence of newer German tanks such as the Tiger I and Panther tanks, plus the establishment upgunned Panzer IVs made these more able to take on Allied tanks than the Panzer III. The Panzer III began slowly to be relegated to secondary roles such as training or anti-partisan activities. Nevertheless, the Panzer IIIs proved a versatile armored platform in German service, as even though it was obsolete in late 1941, it was constantly upgraded with better guns, better protection, or modified completely to fit a different role more efficiently than its original. Even when phased out of service, its chassis was used as the basis of Germany's most lethal tank destroyer, the StuG III.

The Panzer III, after being relegated as secondary roles, was made into an infantry support tank with the Panzer III Ausf. N variant, which featured the 75 mm KwK 37 howitzer originally equipped in the first few Panzer IV models.

Pz. Kpfw. III Aus. A, B, C, D, E (Sd. Kfz. 141)
Reports on the early development of the Pz. Kw. III do not agree. The following summary conforms to the best information available.

Model A: Weighed about 20 tons. Its suspension arrangement consisted of eight small bogie wheels each side on semi-elliptical, laminated springs, with three return rollers. Motivating power was generated by a Maybach V-12 gasoline engine rated 300 hp. Armament consisted of a 3.7 cm Kw. K., two light machine guns in the turret, and one light machine gun in the front plate of the superstructure. Armor consisted of 30 mm plate all around.

Model B: Same as Model A except for suspension which consisted of five medium size bogie wheels and two return rollers.

Model C: Principal change was the new type suspension which incorporated six bogie wheels and three return rollers, which became standard for the Pz. Kw. III tank. It is believed that torsion bar suspension evolved in this model.

Model D1: At this point in the development the previous models were given the nomenclature D1. Commander’s tanks are known to have been produced serially from this period on.

Model E: Represents the first model in which the definite Pz. Kw. III type has been crystallized. It embodies the improvements made in previous models. It carried the same armament (3.7 cm Kw. K.) and had a suspension arrangement of six bogie wheels sprung on torsion bars and three return rollers.

A self-propelled equipment known as the Sturmgeschütz has been developed from the Pz. Kw. III. It consists of the Pz. Kw. III chassis mounting a short-barreled 7.5 cm Kw. K. The chassis was later used to mount the 7.5 cm Kw. K. 40, long-barreled gun, and the 10.5 cm howitzer.

Pz. Kpfw. III Aus. F, G, H (Sd. Kfz. 141)
Model F: This is the first tank of the series to mount a 5.0 cm Kw. K. electrically fired tank gun in place of the 3.7 cm Kw. K. and also the first to have a new type mantlet. This mantlet has a thick shield on the front which moves with the gun. A single machine gun is mounted coaxially on the right of the 5.0 cm gun and the hull machine gun is retained.

The hull consists of three separate subassemblies: (1) lower hull, (2) front superstructure carrying turret, and (3) rear superstructure covering the engine compartment. All units are of single skin welded construction.

The turret forms the roof of a spacious fighting compartment, being mounted over the middle part of the hull. It has no rotating platform, the commander and the gunner having seats suspended from and rotating with the turret. The loader apparently stands on the floor of the fighting compartment. The commander’s cupola is bolted to the roof of the turret on the center-line to the rear.

The suspension is the same as that used in Model E.

The engine is the Maybach V-12, gasoline, rated 320 hp. Its transmission is the synchromesh type with 10 speeds forward and 4 reverse. Its steering is of the epicyclic, clutch brake type with hydraulic control.

Model G: Identical in armament, mantlet, and mechanical components to Model F, the only difference being in the cupola, which is more squat and has all-around vision.

Model H: This model has additional 32 mm plates bolted on the front of the superstructure, on the upper and lower nose plates and on the tail plate. The outstanding recognition features of this model are its front sprocket which has six spokes, and its rear idler which is more open than the earlier type, though it has eight spokes. Wider tracks and narrower bogie wheels are also used.

Pz. Kpfw. III Aus. J, K (Sd. Kfz. 141)
Model J—The principal differences between Model J and earlier models are:

1. Increased thickness of basic armor plate on certain front and rear plates from 30 mm to 50 mm and the addition of spaced armor on the front of the gun mantlet and the front plate of the superstructure.

2. Hydraulically operated steering in the earlier models has been replaced by mechanical steering. As previously reported, the complicated Maybach Variorex ten-speed gear was abandoned in Model H in favor of a manual six-speed and reverse gear box.

3. Wider tracks—15 inches instead of 14 1/8 inches. The heavier track necessitated a change in the spacing of the return rollers. Front and rear rollers are now mounted directly over the Luvax shock absorbers and prevent the track fouling the latter.

4. The tail plate has been modified to give better protection to the rear air outlet; it also allows the smoke device to be mounted inside the plate.

5. One or two mild steel bars, welded at each end, are fixed across the middle of the nose plate. The track shoes are placed behind the bars and are held in position by the bridge of the shoe.

6. The mounting of the 5.0 cm Kw. K. 39 (long gun) was incorporated in the latest of the Model J tanks.

The most prominent recognition points of this model are: the mounting of the hull machine gun is of prominent ball type; the driver’s visor consists of a single hinged piece of armor instead of two separate plates; the front sprocket and rear idler are similar to those in Model H; particularly squat turret, pear-shaped with circular cupola well set to the rear.

Model K—Same as Model J. This model mounted the 5.0 cm long gun (Kw. K. 39).

Pz. Kpfw. III Aus. L, M, N, O (Sd. Kfz. 141)
Model L: In this model the loader’s visor in the right of the gun mantlet has been omitted as well as the vision openings on each side of the turret in front of the access doors. Spaced armor is always fitted on the front of the superstructure and fittings for spaced armor are provided on the gun mantlet, but the curved spaced plate is not always fitted in the latter position. The long 5.0 cm Kw.K. 39 is balanced by a torsion bar. The torsion bar compensator is mounted on the roof of the turret and connected to the gun by means of a link. On the cupola of this model a metal framework is attached, probably to serve as a rest for the gun. In other respects Model L is identical to Model J. German markings on this tank indicate that it was prepared for tropical or desert use. Preparation consisted of slight changes in the air-cooling system and addition of deflectors on the rear of the tank to prevent the exhaust gases and cooling air from striking the ground.

Model M: This model is similar to Model L with the exception that it has no loading doors fitted on the side of the hull.

Models N, O: Reports indicate the existence of these models but no details are available.

A few Model L tanks and many Model M and N tanks now mount the 7.5 cm Kw.K., which is the short gun formerly fitted in the Pz. Kpfw. IV. Recent models of the Pz. Kpfw. III now in service mount, therefore, either the 5 cm long gun or the 7.5 cm short gun. When the latter gun is mounted, the spaced armor plate on the gun mantlet and the fittings for it are omitted altogether. The mantlet is one of the Pz. Kpfw. III type without loader’s visor, but the recoil gear casing and armored protecting sleeve in front of the mantlet are of the type provided on the Pz. Kpfw. IV. In a captured Model N mounting a short 7.5 cm Kw.K., the sighting telescope was a T.Z.F. 5b, which is the type used with this gun in the older Pz. Kpfw. IV’s, Stu. G. 7.5 cm K.

Pz. Kpfw. III (Fl. W. 41): Flamethrower Tank
The flamethrowing tank, put into service in 1942, consists of the standard Pz. Kpfw. III tank equipped with a flame projector instead of the usual tank gun. A machine gun is mounted coaxially in the turret and another is ball mounted in the front plate of the hull. Its road performance will approximate that of the Pz. Kpfw. III tank.

The flame tube, which looks like an ordinary cannon, contains 3 jets. The barrel behind the curved position of the armored shield is 134 cm long and at the flame end is 12 cm in diameter. Movement of the gun horizontally and vertically is controlled by two handwheels within reach of and to the left front of the tank commander. Propulsion of the liquid fuel for the flame thrower is achieved by means of a centrifugal pump driven by a small two-cylinder gasoline engine which is located in the engine compartment to the left of the tank motor. The fuel tanks are located beside the tank commander to the inside right and left side of the tank chassis.