Sturmpanzerwagen :

The Sturmpanzerwagen A7V was an early AFV (armored fighting vehicle) or tank that was introduced by Germany in 1918, near the end of World War I. One hundred vehicles were ordered in early 1918, but only 20 were delivered. 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.

Sturmpanzerwagen History :

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 meters 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 1917 the design was extended to be a universal chassis which could be used as a base for both a tank and unarmored  (“Überlandwagen“) Over-land vehiclecargo carriers.

The first Sturmpanzerwagen prototype was completed by Daimler-Motoren-Gesellschaft at Berlin-Marienfelde and tested on 30 April 1917. A wooden mock-up of a final version was completed in May 1917 and demonstrated in Mainz with 10 tons of ballast to simulate armor. During final design the rear-facing cannon was removed and the number of machine-guns was increased to six. The first pre-production Sturmpanzerwagen A7V was produced in September 1917, followed by the first production model in October 1917.

Sturmpanzerwagen Design :

The Sturmpanzerwagen A7V was 7.34 meters (24.1 ft) long, 3 meters (9.8 ft) wide, and the maximum height was 3.3 metres (11 ft). The tank had 20 mm of steel plate at the sides, 30 mm at the front and 10 mm for the roof; however the steel was not hardened armour plate, which reduced its effectiveness. It was thick enough to stop machine-gun and rifle fire, but not larger calibers. This offered protection comparable to the thinner armor of other tanks of the period, which used hardened steel. The crew normally consisted of up to seventeen soldiers and one officer: commander (officer, typically a lieutenant), driver, mechanic, mechanic/signaler, twelve infantrymen (six machine gunners, six loaders), and two artillerymen (main gunner and loader).

Sturmpanzerwagen Propulsion :

Power came from two centrally mounted Daimler 4-cylinder petrol engines delivering 100 horsepower (75 kW) each; the Sturmpanzerwagen A7V carried 500 liters (110 imp gal) of fuel. The top speed was about 15 kilometers per hour (9.3 mph) on roads and 5 kilometers per hour (3.1 mph) across country. The 24 wheel suspension was individually sprung – an advantage over the unstrung British tanks. Compared to other World War I tanks the road speed was quite high, but the tank had very poor off-road capability and was prone to getting stuck. The large overhang at the front and the low ground clearance meant trenches or very muddy areas were impassable. This was worsened by the fact that the driver could not see the terrain directly in front of the tank, due to a blind spot of about 10 meters. However, on open terrain it could be used to some success and offered more firepower than the armoured cars that were available. Power-to-weight ratio was 6.8 hp/ton (5.1 kW/ton), trench crossing: 7 feet (2.1 m), ground clearance: 7.5 to 15.75 inches (190 to 400 mm).

Sturmpanzerwagen Variant :

A7V-U: An attempt to reproduce the all-terrain capability of the British tanks, the A7V-U was still based on the Holt chassis but had a rhomboidal hull and all-round tracks. The cab was similar to, but bigger than, that on the A7V and was mounted on top of the forward part of the hull. Two 57mm guns were carried in sponsons similar to the British type. The prototype was built in June 1918, and trials showed that it was nose-heavy and had a high center of gravity, and the 40-ton weight caused maneuverability problems. On the assumption that the problems could be rectified, twenty were ordered in September 1918, the same month work on the design was halted. Drawings for two improved designs were prepared, but the war ended before any were produced. Thirty chassis were assigned for completion as Überlandwagen supply carriers, but not all were completed before the end of the war.

Sturmpanzerwagen Specifications :

General characteristics

• Crew: 11 ( up to 18)
• Length: 25.85 meters (84.8 ft)
• Weight: 33 t (32 long tons; 36 short tons) battle weight
• Armour: 30 mm Front / 15 mm Sides / 20 mm Rear
• Main Armament: 57 mm gun (500 rounds)
• Secondary Armament: 6 × 7.9 mm machine guns (36,000 rounds)
• Power plant: 2 × Daimler-Benz 4-cylinder
• Power Output:  200 hp (149 kW)
• Maximum speed: 15 km/h (9 mph) road / 4 mph field
• Operational Range:  30–80 km (20–50 miles)