Staff Writer (Updated: 4/1/2016):
Ultimately, the A7V proved itself a limited endeavor for it was a cumbersome, tactically restricted beast with little to recommend itself when compared to the British heavies in play. It was acquired in just 20 examples by the end of the conflict. It did, however, take part in history's first-ever "tank-versus-tank" duel, this outside of Villers-Bretonneux in April 1918. As with other German armored vehicle designs of the war, Joseph Vollmer's name was tied to the development of the A7V.
The A7V was born through a boxy, armored hull superstructure fitted atop the modified tracked components of a Holt tractor. The result was a vehicle that appeared to have no true front end - the only telltale sign being its 57mm field gun fitted at the bow. Various captured British, Belgian, and Russian 57mm field guns were uses during production of the twenty vehicles. To this was added 6 x Maxim MG08 machine guns - two at ports along each hull side and a pairing at the rear hull face. The field gun required at least two personnel to operate effectively as did each machine gun. In addition to the driving/steering crew and onboard engineers, the total crew numbered 18 or more. About 30,000 rounds of machine gun ammunition were carried to go along with 500 x 57mm projectiles.
Externally, the A7V mimicked the design approach seen in the period's armored train cars. Its armor plating was near-vertical along all of the available faces and there was a centrally-mounted cupola-type assembly fitted on the roof - this area reserved for the driving compartment. Unlike an armored train car the A7V carried its own powerpack and running gear as well as fuel which did not restrict the vehicle to a railway network. Hinged rectangular doors offered the needed entry/exit for the crew. Armor protection ranged from 30mm at the front facing to 20mm at the rear and 15mm protecting the sides. Combat weight was listed at 36 tons (short).
The vehicle sat atop a rather shallow track system (ground clearance was measured in mere inches) which utilized some fifteen roadwheels to a hull side. Power was through 2 x Daimler-Benz 4-cylinder gasoline engines developing 200 horsepower and mated to Adler gearboxes and differentials while being exhausted through a stack set along the lower hull sides. The suspension system was of vertical springs, retained from the Holt tractor design. All told, the vehicle managed a ponderous 9 miles per hour on roads and 4 miles per hour when attempting cross-country travel. Ranges were limited to 50 miles maximum if the vehicle did not suffer a mechanical breakdown or get bogged down in the terrain.
As with all early tank forms, the Sturmpanzerwagen held a crew compartment that was cramped, smelly, and noisy - very industrial. The engine was installed at center with the main running gear components resting under the rear section of the hull. Two drivers sat in the upper center bridge area operating steering wheel and lever controls. The crew had access to ropes strewn over their heads to help stabilize themselves during rough-terrain travel.