The Origins of the Panzer IV
The Panzer IV was the brainchild of German general and innovative armored warfare theorist General Heinz Guderian. In concept, it was intended to be a support tank firing mainly high explosive for use against enemy anti-tank guns and fortifications. Ideally, the tank battalions of a panzer division were each to have three medium companies of Panzer IIIs and one heavy company of Panzer IVs.
On 11 January 1934, the German army wrote the specifications for a "medium tractor", and issued them to a number of defense companies. To support the Panzer III, which would be armed with a 37-millimetre (1.46 in) anti-tank gun, the new vehicle would have a short-barrelled 75-millimetre (2.95 in) howitzer as its main gun, and was allotted a weight limit of 24 tonnes (26.46 short tons). Development was carried out under the name Begleitwagen ("accompanying vehicle") or BW, to disguise its actual purpose, given that Germany was still theoretically bound by the Treaty of Versailles. MAN, Krupp, and Rheinmetall-Borsig each developed prototypes with Krupp's being selected for further development.
The chassis had originally been designed with a six-wheeled interleaved suspension, but the German Army amended this to a torsion bar system. Permitting greater vertical deflection of the roadwheels, this was intended to improve performance and crew comfort both on- and off-road. However, due to the urgent requirement for the new tank, neither proposal was adopted, and Krupp instead equipped it with a simple leaf spring double-bogie suspension.
A Panzer Ausf.A rolls into the Sudetenland 1938.
The prototype required a crew of five men; the hull contained the engine bay to the rear, with the driver and radio operator, who doubled as the hull machine gunner, seated at the front-left and front-right, respectively. In the turret, the tank commander sat beneath his roof hatch, while the gunner was situated to the left of the gun breech and the loader to the right. The turret was offset 66.5 mm (2.62 in) to the left of the chassis center line, while the engine was moved 152.4 mm (6.00 in) to the right. This allowed the torque shaft to clear the rotary base junction, which provided electrical power to turn the turret, while connecting to the transmission box mounted in the hull between the driver and radio operator. Due to the asymmetric layout, the right side of the tank contained the bulk of its stowage volume, which was taken up by ready-use ammunition lockers.
Accepted into service as the Versuchskraftfahrzeug 622 (Vs.Kfz. 622), production began in 1936 at Krupp-Grusonwerke AG's factory at Magdeburg.
Ausf. A to Ausf. F1
Panzer IV Ausf. C
The first mass-produced version of the Panzer IV was the Ausführung A (abbreviated to Ausf. A, meaning "Variant A"), in 1936. It was powered by Maybach's HL 108TR, producing 250 PS (183.87 kW), and used the SGR 75 transmission with five forward gears and one reverse, achieving a maximum road speed of 31 kilometres per hour (19.26 mph). As main armament, the vehicle mounted the Kampfwagenkanone 37 L/24 (KwK 37 L/24) 75 mm (2.95 in) tank gun, which was a low-velocity gun designed to mainly fire high-explosive shells. Against armored targets, firing the Panzergranate (armor-piercing shell) at 430 metres per second (1,410 ft/s) the KwK 37 could penetrate 43 millimetres (1.69 in), inclined at 30 degrees, at ranges of up to 700 metres (2,300 ft). A 7.92 mm (0.31 in) MG 34 machine gun was mounted coaxially with the main gun in the turret, while a second machine gun of the same type was mounted in the front plate of the hull. The Ausf. A was protected by 14.5 mm (0.57 in) of steel armor on the front plate of the chassis, and 20 mm (0.79 in) on the turret. This was capable only of stopping artillery fragments, small-arms fire, and light anti-tank projectiles.
The 300 horsepower Maybach HL 120TRM engine used in most Panzer IV production models.
After manufacturing 35 tanks of the A version, in 1937 production moved to the Ausf. B. Improvements included the replacement of the original engine with the more powerful 300 PS (220.65 kW) Maybach HL 120TR, and the transmission with the new SSG 75 transmission, with six forward gears and one reverse gear. Despite a weight increase to 16 t (18 short tons), this improved the tank's speed to 39 kilometres per hour (24 mph). The glacis plate was augmented to a maximum thickness of 30 millimetres (1.18 in), and the hull-mounted machine gun was replaced by a covered pistol port.
Forty-two Panzer IV Ausf. Bs were manufactured before the introduction of the Ausf. C in 1938. This saw the turret armor increased to 30 mm (1.18 in), which brought the tank's weight to 18.14 t (20.00 short tons).[ After assembling 40 Ausf. Cs, starting with chassis number 80341 the engine was replaced with the improved HL 120TRM. The last of the 140 Ausf. Cs was produced in August 1939, and production changed to the Ausf. D; this variant, of which 248 vehicles were produced, reintroduced the hull machine gun and changed the turret's internal gun mantlet to an external one. Again protection was upgraded, this time by increasing side armor to 20 mm (0.79 in). As the German invasion of Poland in September 1939 came to an end, it was decided to scale up production of the Panzer IV, which was adopted for general use on 27 September 1939 as the Sonderkraftfahrzeug 161 (Sd.Kfz. 161).
In response to the difficulty of penetrating British Matilda Infantry tanks during the Battle of France, the Germans had tested a 50 mm (1.97 in) gun—based on the 5 cm PaK 38 L/60 anti-tank gun—on a Panzer IV Ausf. D. However, with the rapid German victory in France, the original order of 80 tanks was canceled before they entered production.
In September 1940 the Ausf. E was introduced. This had 50 millimetres (1.97 in) of armor on the bow plate, while a 30-millimetre (1.18 in) appliqué steel plate was added to the glacis as an interim measure. Finally, the commander's cupola was moved forward into the turret. Older model Panzer IV tanks were retrofitted with these features when returned to the manufacturer for servicing. Two hundred and eighty Ausf. Es were produced between December 1939 and April 1941.
The short-barreled Panzer IV Ausf. F1.
In April 1941 production of the Panzer IV Ausf. F started. It featured 50 mm (1.97 in) single-plate armor on the turret and hull, as opposed to the appliqué armor added to the Ausf. E, and a further increase in side armor to 30 mm (1.18 in). The weight of the vehicle was now 22.3 tonnes (24.6 short tons), which required a corresponding modification of track width from 380 to 400 mm (14.96 to 15.75 in) to reduce ground pressure. The wider tracks also facilitated the fitting of ice sprags, and the rear idler wheel and front sprocket were modified.
The designation Ausf. F was changed in the meantime to Ausf. F1, after the distinct new model, the Ausf. F2, appeared. A total of 464 Ausf. F (later F1) tanks were produced from April 1941 to March 1942, of which 25 were converted to the F2 on the production line.
A good study of the main armament of the Panzer IV Ausf .F taken in 1942 in the Army Group Centre sector.
Ausf. F2 to Ausf. J
On May 26, 1941, mere weeks before Operation Barbarossa, during a conference with Hitler, it was decided to improve the Panzer IV's main armament. Krupp was awarded the contract to integrate again the same 50 mm (1.97 in) Pak 38 L/60 gun into the turret. The first prototype was to be delivered by November 15, 1941. Within months, the shock of encountering the Soviet T-34 medium and KV-1 heavy tanks necessitated a new, much more powerful tank gun.
In November 1941, the decision to up-gun the Panzer IV to the 50-millimetre (1.97 in) gun was dropped, and instead Krupp was contracted in a joint development to modify Rheinmetall's pending 75 mm (2.95 in) anti-tank gun design, later known as 7.5 cm PaK 40 L/46. Because the recoil length was too long for the tank's turret, the recoil mechanism and chamber were shortened. This resulted in the 75-millimetre (2.95 in) KwK 40 L/43. When firing an armor-piercing shot, the gun's muzzle velocity was increased from 430 m/s (1,410 ft/s) to 990 m/s (3,250 ft/s). Initially, the gun was mounted with a single-chamber, ball-shaped muzzle brake, which provided just under 50% of the recoil system's braking ability. Firing the Panzergranate 39, the KwK 40 L/43 could penetrate 77 mm (3.03 in) of steel armor at a range of 1,830 m (6,000 ft).
Grenadiers crowd aboard a Panzer IV Ausf.J, Russia 1944.
The 1942 Panzer IV Ausf. F2 was an upgrade of the Ausf. F, fitted with the KwK 40 L/43 anti-tank gun to counter Soviet T-34 and KV tanks.
The Ausf. F tanks that received the new, longer, KwK 40 L/43 gun were named Ausf. F2 (with the designation Sd.Kfz. 161/1). The tank increased in weight to 23.6 tonnes (26.0 short tons). One hundred and seventy-five Ausf. F2s were produced from March 1942 to July 1942. Three months after beginning production, the Panzer IV. Ausf. F2 was renamed Ausf. G.There was little to no difference between the F2 and early G models.
NEW ARMAMENT OF GERMAN PZ.KW. 4
Tactical and Technical Trends, No. 20, March 11th, 1943
As previously reported in Tactical and Technical Trends (No. 4, p. 15) recent models of two German tanks, the Pz.Kw. 3 and 4, have been fitted with more powerful armament, as shown in the accompanying sketches. These sketches are based on photographs of German tanks captured by the British in North Africa.
PZ.Kw. IV
The principal armament of this tank is a long-barrelled 75-mm gun, the 7.5-cm Kraftwagenkanone 40 (7.5-cm Kw.K. 40). It is reported that the muzzle velocity is 2,400 feet per second (also reported at 2,620 feet per second), and that 2.44 inches of armor plate can be penetrated at 2,000 yards at an angle of impact of 30 degrees. The long barrel, terminating in a muzzle brake, extends beyond the nose of the tank, and an equilibrator was provided, in the particular tank examined, to balance the consequent muzzle preponderance.
The equilibrator is fixed to the floor of the turret and extends vertically to an attachment near the rear of the piece; it is 6 inches in diameter and 21 1/2 inches long. The gun is also provided with a traveling lock inside the turret. The traveling lock consisted of two steel bars about 1/2 inch by 2 inches and 15 inches in length. There were hardened semi-hemispherical surfaces about 1 1/2 inches in diameter projecting from each end of the steel bars, and these fitted into corresponding indentations on either side of lugs attached to the gun and to the turret roof. The steel bars were connected by two bolts; tightening the bolts provided a very positive lock.
Panzer IV of the 4th Panzer Division (Panzerregiment 35)
Three types of ammunition were found with this tank: nose-fuzed HE; hollow-charge HE; and armor-piercing HE, this being an armor-piercing shell with a ballistic nose and an HE charge.
The Ausf.G
During its production run from May 1942 to June 1943, the Panzer IV Ausf. G went through further modifications, including another armor upgrade. Given that the tank was reaching its viable limit, to avoid a corresponding weight increase, the appliqué 20-millimetre (0.79 in) steel plates were removed from its side armor, which instead had its base thickness increased to 30 millimetres (1.18 in). The weight saved was transferred to the front, which had a 30-millimetre (1.18 in) face-hardened appliqué steel plate welded (later bolted) to the glacis—in total, frontal armor was now 80 mm (3.15 in) thick. This decision to increase frontal armor was favorably received according to troop reports on November 8, 1942, despite technical problems of the driving system due to added weight. At this point, it was decided that 50% of Panzer IV productions would be fitted with 30 mm thick additional armor plates.
