As the PzKpfw IV Ausf F1 was rolling off production lines, the T-34 was encountered on the Russian front. Hitler ordered the PaK 40 antitank gun fitted into all new PzKpfw IVs.
On November 18, 1941 the Ordnance Department issued Order #917/41 gKdos Wa. Pruef. 4 to Friedrich Krupp AG of Essen and Rheinmetall-Borsig AG to design a replacement for the short barrel 75 mm gun being used.
The turret of the PzKpfw IV Ausf F2 was welded and there were seats for the commander, gunner, and loader.
The commander had a cupola that was towards the rear of the roof that had five observation ports. The front port was lined up with the main armament would fire.
In front of the side hatches was an observation port. On each side of the mantlet were observation ports. Some of the turrets were produced without the right side port.
The turret roof had a signal port. At the rear of the turret were two pistol ports.
To extract the fumes after firing, there was a fan in the roof of the turret.
There was a DKW two cylinder two cycle 10 HP 500 cc gasoline engine that provided power for the turret traverse.
The joints were austenitic steel welds and the plates were made of chromium-molybdenum steel. The hull was separated by 2 bulkheads into the driving, fighting, and engine compartment.
The transmission and the final drive assemblies were housed in the driving compartment. The driver and hull gunner / radio operator had their seats located in the front.
Under the fighting compartment was 105 gallons of fuel in tanks.
There were two hinged and one bolted maintenance hatches in the front glacis plate.
At the right front of the hull was the machine gun that was operated by the radio operator.
The welded superstructure was bolted to the top of the hull. The superstructure extended out over the sides of the hull to make room for a large turret.
Hatches for the driver and hull gunner were in the roof.
The 75 mm Kampfwagenkanone 44 (later KwK 40) L/43 was mounted on a trunnion axis. Extending through the mantlet was the recoil mechanism that added more protection.
Early models had single baffle, but later models had double baffle muzzle brake.
||89 mm @ 30°
Ammunition storage was altered to allow for the larger rounds. The gunner's and commander's seat was altered to allow more room. There was an auxiliary hand crank for traverse for the loader.
The Maybach HL 120 TRM was built under license by Norddeutsche Motorenbau GmbH of Berlin-Niederschoeneweide.
The engine could output 300 HP at 3,000 rpm but was restricted to 265 HP at 2,600 rpm.
Air entered the engine compartment on the left. The air then went through two radiators and then was drawn over the engine by two 10 bladed fans. There was a large air filter for the engine. A propeller shaft transmitted the power to the Zahnradfabrik Friedrichshafen AG gearbox.