A7V German Heavy Tank

The A7V was a tank introduced by Germany in 1918, during World War I. One hundred chassis were ordered in early 1918, ten to be finished as fighting vehicles with armoured bodies and the remainder as cargo carriers. The number to be armoured was later increased to 20. They were used in action from March to October of that year, and were the only tanks produced by Germany in World War I to be used in operations.

History
Following the appearance of the first British tanks on the Western Front, the Allgemeines Kriegsdepartement, 7. Abteilung, Verkehrswesen ("General War Department, 7th Branch, Transportation"), was formed in September 1916.

The project to design and build the first German tank was placed under the direction of Joseph Vollmer, a reserve captain and engineer. It was to have a mass of around 30 tons, be capable of crossing ditches up to 1.5 metres wide, have armament including cannon at front and rear as well as several machine-guns, and reach a top speed of at least 12 km/h. The running gear was based on the Holt tractor, copied from examples loaned by the Austrian Army. After initial plans were shared with the Army in December 1916 the design was extended to be a universal chassis which could be used as a base for both a tank and unarmoured Überlandwagen ("over-land vehicle") cargo carriers.

The first prototype was completed by Daimler-Motoren-Gesellschaft at Berlin-Marienfelde and tested on 30 April 1917. A wooden mockup of a final version was completed in May 1917 and demonstrated in Mainz with 10 tons of ballast to simulate armour. During final design the rear-facing cannon was removed and the number of machine-guns was increased to six. The first pre-production A7V was produced in September 1917, followed by the first production model in October 1917. The tanks were given to Assault Tank Units 1 and 2, founded on 20 September 1917, each with five officers and 109 NCOs and soldiers.

A7V/U
The A7V/U was an attempt to make a tank that could match the British Heavy tanks. So they practically copied the British tank outing "all round tracks" on an A7V chassis. It was given two 57mm gun in gun supinations. 30 were ordered but none were completed before the end of the war.