The first vehicle to be produced in any numbers for the Panzerwaffe was, of course, the tiny Panzer I, which at the time was known as the MG Panzerwagen. Delivery of 318 of these had been made by August 1935, along with 15 of the Zugfuhrerwagen, which was later to become the Panzer III. One aspect of tank design which the Germans got absolutely right from the very outset was to identify the importance of radio communications. Although initially only the command tanks were fitted with radios that could both transmit and receive, the other vehicles were at last equipped with receiving radio sets, and this was a major advance upon the thinking of many of the countries which would come to oppose Germany. Throughout 1934 exercises continued with the experimental tank units and a number of other valuable lessons quickly became apparent, particularly the need for close co-operation between the air forces and the tanks on the ground. At this point the first serious tank tactics which were to bring so much success during the Second World War began to appear. It was soon obvious that the tanks needed to be employed on a relatively narrow front. A divisional front was estimated at about three kilometres, a great change from the wide fronts of the Great War. It was still obvious to the German High Command that the decisions which were being made, were based on theory, rather than practice. Germany - and indeed every other nation of the time - had no practical experience to draw upon, therefore a number of educated guesses were made.
In January 1936 General Beck reported to the High Command, his findings being based on a study of a French organisation. He was also very critical of the slow rise in production capacity which was hampering the development of the tank force. Interestingly, the debate about which tasks tanks were suitable for, and whether specialist machines had to be developed for each task, was already beginning to take shape. Beck’s report clearly stated that the three main tasks of the Panzers were supporting infantry, operating in units with other mobile weapons and, finally, combating other tanks. Beck himself was unable to come to a decision about whether a single tank should be developed with the capability to take on each of these purposes or whether a specialist vehicle should he designed for each purpose.
Ultimately the decision was that the light tanks would be used in a scouting role and that an infantry support tank would be developed which was ultimately to come to fruition in the form of the Panzer IV. This decision cast the Panzer III in the role of main battle tank. Amazingly the decision was taken that the 3.7cm gun which initially equipped the Panzer III would be sufficient for the battle conditions. The various types of German tank design were to cater for most eventualities on the battlefield. The Panzer I and II were earmarked for the reconnaissance role. The Panzer III was essentially designed for break-through and anti-tank operations and the Panzer IV was designed to provide close support for the infantry battling their way forward against dug-In positions. Almost from the outset the limitations of the design for the Panzer I were obvious. The armament in the form of two machine guns, was inadequate for most purposes on the battlefield. In addition the very thin armor gave protection only against rifle bullets: almost any battlefield weapon could penetrate the armor. More significant was the fact that the crew was comprised of only two men.
In October 1935 General Liese, head of the Heeres Waffenamt issued a report which gave the limitations of the tanks. He noted that the MG Panzerwagen (Panzer I), although fitted out only with two 7.9mm machine guns, could be adapted to attack armored cars and other light tanks if it was issued with special S.M.P. steel core ammunition. In the case of the MG Panzer II, it was noted that the muzzle velocity of the 2cm gun could penetrate up to 10mm of armored plate at a range of up to 700 metres. It was therefore decided that the Panzer II could engage armored cars with success, and was also fully functional for combat against tanks with approximately the same armor as itself. Liese noted that the tanks most likely to be encountered in large numbers in a war against the French were the light Renault Ml7 and Ml8 tanks, of which there were about three thousand operational in the French forces at the time. It was also thought that the Panzer II would be the equal of the Renault NC37 and NC31 tanks. Against the heavier French tanks, including the Char B, it was noted that the Panzer II was practically worthless. Despite these reservations large-scale delivery of the Panzer II was already in train and was expected to commence from 1st April 1937. As regards the new Panzer III, which was designed to be the main battle tank, it was obvious that, even in 1935, Liese was already beginning to have reservations about the effectiveness of the 37mm gun. Originally the 37mm L/45 had been planned for this vehicle, but it was urged that the experimental tanks be upgraded to include the L/65 version, which gave a much higher muzzle velocity and some real prospect of penetrating the 40mm thick armored plate of the new French medium tanks. With this in mind it was obvious at this stage that a 50mm gun would be a better proposition for the Panzer III; however the addition of the larger gun would demand a significant increase in the diameter of the turret which would in turn mean radical redevelopment of the chassis. Given the pressures of time and the need to equip the formations quickly Liese came to the conclusion that the 37mm L/65 was the favoured route, although it is interesting that the limitations of its design had already been noted.
The PzKpfw III (Panzerkampfwagen III Sd.Kfz.141)was therefore designed to be the Wehrmacht’s main combat machine and was developed by Daimler-Benz in the mid 1930s under the pseudonym Zugfuhrerwagen, which means platoon commanders’ truck. The first prototype of the PzKpfw III was produced by Daimler-Benz in Berlin 1936.
Following numerous modifications, the Ausf. A (1-Serie) appeared in May 1937 and : by the end of 1937, 15 were produced. Only 8 of the Ausf. As were fully armed and the unarmed machines were used for further testing and modification.
Daimler-Benz produced 15 Ausf. Bs (2-Serie) in 1937, 15 Ausf. Cs (3a-Serie) by the beginning of 1938; it continued by introducing the next variant the Ausf. D (3b-Serie), 55 of which were produced in 1939. Of the entire Ausf. Ds production run, only 30 were armed.
All early models of the Panzer III, including the Ausf A/B/C/D were pre-prototypes of the whole series and were unsuitable for large scale production. Every new prototype was a marginal improvement on the last. Each model featured a different type of suspension, a variation on the Maybach DSO, such as the HL 108 TR engine. Only a relatively few vehicles saw combat in the early stages of the war; the Ausf. D saw service during fighting in Denmark and Norway in May 1940 and in Finland in 1941/42. In February 1940, the remaining Panzer Ills Ausf D were handed over to NSKK for training purposes.
The first Panzer III model to go into anything like full-scale production was the Ausf E of which 96 were produced. With a thicker 30mm frontal armor, a Maybach HL 120TR engine and new suspension and gearbox raising its weight up to 19.5 tonnes, the Ausf. E was the best machine so far.
By 1940, and during the ‘E’ model production, it was decided to fit all models with a 50mm gun as standard. The L/42 gun was fitted on Ausf. E, F, G and H. In an ill-considered deal which would come back to haunt them, the Germans actually sold Two PzKpfw III tanks to the Soviet Union in the Summer of 1940 under the Ribbentrop-Molotov treaty. They were tested by the Soviets alongside the early T-34/76 tanks. The German PzKpfw III proved to be faster than Soviet T-34/76 and BT-7, reaching a maximum speed of 69km/h. However it was obvious that the Soviet T-34 was far superior in armor protection and armament even if lacking in esthetics and overall mechanical reliability, when compared to German PzKpfw III tanks. The PzKpfw III was also found to be far less less noisy than Soviet T-34. It was discovered that the T-34 could easily be heard from a distance of 450m, while PzKpfw III could only be heard when it approached to within 150-200m.
From 1941, Hitler insisted that the more powerful L/60 (50mm) gun was fitted on Ausf J-1. In 1942, 104 Ausf J’s were converted to Panzerbefehlswagen III (Command Tanks) and in April 1943, 100 Ausf. M’s were converted by Wegmann into the Flammpanzer (Flamethrower Tanks); designed to fight in urban areas such as Stalingrad. Although the models produced never actually reached Stalingrad, they did see service on the Eastern Front. Additionally, many Ausf. Ms were converted into the Sturmgeschütz III or the Ausf. N.
The Panzer III provided the main battle tank for the Panzer Divisions in the early years of the war, yet its production was slow and stopped altogether in August 1943, in 1943/44, the Panzer III prototypes were fitted with dozers and were used to clean up the streets of war-torn cities.