Panzer I - Development History

Development History

The post-World War I Treaty of Versailles of 1919 prohibited the design, manufacture and deployment of tanks within the Reichswehr. Paragraph Twenty-four of the treaty provided for a 100,000-mark fine and imprisonment of up to six months for anybody who " armoured vehicles, tanks or similar machines, which may be turned to military use".

Despite the manpower and technical limitations imposed upon the German Army by the Treaty of Versailles, several Reichswehr officers established a clandestine General Staff to study World War I and develop future strategies and tactics. Although at first the concept of the tank as a mobile weapon of war met with apathy, German industry was silently encouraged to look into tank design, while quiet cooperation was undertaken with the Soviet Union. There was also minor military cooperation with Sweden, including the extraction of technical data that proved invaluable to early German tank design. As early as 1926 various German companies, including Rheinmetall and Daimler-Benz, produced a single prototype armed with a large 75-millimeter cannon (the Großtraktor, "large tractor", was so codenamed to veil the true purpose of the vehicle). Only two years later prototypes of the new Leichttraktor ("light tractor"), were produced by German companies, armed with 37-millimeter KwK L/45 guns. The Großtraktor was later put into service for a brief period with the 1 Panzer Division; the Leichttraktor remained in testing until 1935.

In the late 1920s and early 1930s German tank theory was pioneered by two figures: General Oswald Lutz and his chief of staff, Lieutenant Colonel Heinz Guderian. Guderian became the more influential of the two and his ideas were widely publicized. Like his contemporary Sir Percy Hobart, Guderian initially envisioned an armored corps (panzerkorps) composed of several types of tanks. This included a slow infantry tank, armed with a small-caliber cannon and several machine guns. The infantry tank, according to Guderian, was to be heavily armored to defend against enemy anti-tank guns and artillery. He also envisioned a fast breakthrough tank, similar to the British cruiser tank, which was to be armored against enemy anti-tank weapons and have a large 75-millimeter (2.95 in) main gun. Lastly, Germany would need a heavy tank, armed with a massive 150-millimeter (5.9 in) cannon to defeat enemy fortifications, and even stronger armor. Such a tank would require a weight of 70 to 100 tonnes and was completely impractical given the manufacturing capabilities of the day.

Soon after rising to power in Germany, Adolf Hitler approved the creation of Germany's first panzer divisions. Simplifying his earlier proposal, Guderian suggested the design of a main combat vehicle which would be developed into the Panzer III, and a breakthrough tank, the Panzer IV. No existing design appealed to Guderian. As a stopgap, the German Army ordered a preliminary vehicle to train German tank crews. This became the Panzer I.

The Panzer I's design history can be traced to 1932's Landwirtschaftlicher Schlepper (La S) (Agricultural Tractor) armored fighting vehicle. The La S was intended not just to train Germany's panzer troops, but to prepare Germany's industry for the mass production of tanks in the near future: a difficult engineering feat for the time. In July 1932, Krupp revealed a prototype of the Landswerk Krupp A, or LKA, with a sloped front glacis plate and large central casemate, a design heavily influenced by the British Carden Loyd tankette. The tank was armed with two obsolescent 7.92-millimeter (.312 in) MG-13 Dreyse machine guns. Machine guns were known to be largely useless against even the lightest tank armor of the time, restricting the Panzer I to a training and anti-infantry role by design.

A mass-produced version of the LKA was designed by a collaborative team from Daimler-Benz, Henschel, Krupp, MAN, and Rheinmetall, exchanging the casemate for a rotating turret. This version was accepted into service after testing in 1934. Although these tanks were referred to as the La S and LKA well beyond the start of production, its official designation, assigned in 1938, was Panzerkampfwagen I Ausführung. A ('model A' or, more accurately, 'batch A'). The first fifteen tanks, produced between February and March 1934, did not include the rotating turret and were used for crew training. Following these, production was switched to the combat version of the tank. The Ausf. A was under-armored, with steel plate of only 13 millimeters (0.51 in) at its thickest. The tank had several design flaws, including suspension problems which made the vehicle pitch at high velocities, and engine overheating. The driver was positioned inside the chassis and used conventional steering levers to control the tank, while the commander was positioned in the turret where he also acted as gunner. The two crewmen could communicate by means of voice tube. Machine gun ammunition was stowed in five bins, containing various numbers of 25-round magazines. Author Lucas Molina Franco suggests that 833 Panzerkampfwagen I Ausf. A tanks were built in total, while authors Bryan Perrett offers the number of 300 and Terry Gander 818 units.

Many of the problems in the Ausf. A were corrected with the introduction of the Ausf. B. The engine was replaced by the water-cooled, six-cylinder Maybach NL 38 TR, developing 98 horsepower (73 kW), and the gearbox was changed to a more reliable model. The larger engine required the extension of the vehicle's chassis by 40 cm (16 in), and this allowed the improvement of the tank's suspension, adding an additional bogie wheel and raising the tensioner. The tank's weight increased by 0.4 tons. Production of the Ausf. B began in August 1935 and finished in early 1937—Franco writes 840 were constructed, but notes that only 675 of these were combat models, while Perrett suggests a total number of 1,500 (offsetting the low number of Ausf. A he proposes) and Gander a total of 675.