INCREASED PROTECTION ON PzKw 3 AND 4
Tactical and Technical Trends, No. 25, May 20th, 1943
The history of the changes in the light medium PzKw 3 and 4 demonstrates how fortunate the Germans were in having a basic tank design that could be improved as battle experience indicated, for a basic design can be improved and still remain familiar to the users. Furthermore, the problems of maintenance and supply of parts are greatly reduced--and these problems are a major factor in keeping tanks ready for operational use.
PzKw 4
(1) Early Models
The PzKw 4, a slightly heavier tank than the 3, has passed through much the same line of development. Little is known about the models A, B, and C of this tank, but Model D was in use during the greater part of the period 1940-43. Specimens of armour cut from Model D have been examined. Of these, only the front plate of the hull appears to be face-hardened; this plate is carburized. All of the plates were high-quality, chromium-molybdenum steel, apparently made by the electric-furnace process.
A Panzer IV Ausf.C still in service with the GrossDeutchsland Division in Novemeber 1943.
The first increase in the armour of this tank was reported in 1941, when it was observed that additional plates had been bolted over the basic front and side armour. The additional plates on the front were 1.18 inches thick, making a total of 2.36 inches, and those on the sides were .79 inches thick, making a total of 1.57 inches. In its early stages, this addition was probably only an improvised measure for increasing the armour protection of existing PzKw 4 models in which the thickest armour was only 1.18 inches.
(2) Model E
In Model E, which had 1.96 inches of single-thickness nose plate, the fitting of additional armor on the front of the superstructure and on the sides of the fighting compartment was continued. Although the arrangement of the additional side armor on this model appears to have been standardized, that on the front superstructure was by no means uniform.
An excellent study of a group of Panzer IV Ausf.E gathered together on exercise in France during 1943. Bringing together this number of vehicles in such close proximity would not have been permitted in Russia.
Three PzKw 4 tanks have recently been examined. In each case, extra armor had been fitted to the vertical front plate carrying the hull machine gun and driver's visor. It had also been added to the sides of the fighting compartment both above and below the track level. The extra protection above the track level extended from the front vertical plate to the end of the engine-compartment bulkhead. It was thus 110 inches long and 15 inches deep. The pieces below the track level were shaped in such a way as to clear the suspension brackets. They were 90 inches long and 30 inches deep. All this extra side protection was .97 inch in thickness.
The vertical front plate was reinforced in three different ways. On one tank, two plates were used; one over the plate carrying the hull machine gun, this additional plate being cut away to suit the gun mounting, and the other plate over the driver's front plate, cut to shape to clear his visor. On the second tank, the arrangement around the hull gun was the same, but the extra protection around the driver's visor consisted of two rectangular plates, one on each side of the visor, there being no extra plate immediately above the visor. On the third tank, the only additional front armor was the plate around the hull machine gun. No additions had been made to the driver's front plate. In all cases, the extra frontal plating was 1.18 inches thick; the nose plate was unreinforced, but it was 1.97 inches thick, and the glacis plate was .97 inch thick. The final drive casings of PzKw 4 tanks of this period were also sometimes reinforced by .79-inch protecting rings. The additional plates on the front were face-hardened.
Women machining tank parts in the Krupp factory.
It is probable that the reinforced armor on the front superstructure of this model will compare closely with that on the corresponding parts of the PzKw 3 of 1941 and that the 1.96-inch nose plates will not differ substantially from those on the more recent PzKw 3's of June 1942, known as "Model J."
The reinforced (.79 inch plus .79 inch) side armor has, however, no counterpart in any PzKw 3 model. The additional plates are of homogeneous quality and have a Brinell hardness of about 370 on the front surface.
(3) Model F
Towards the end of 1941 the Germans introduced a PzKw 4, Model F, having 1.96-inch frontal armor (gun mantlet, front superstructure and hull nose-plates) and 1.18-inch side armor. In this and many other respects, the Model F conforms more closely than its predecessors to the corresponding model of the PzKw 3 (in this case PzKw 3 Model J). So far, the armor of the PzKw 4 Model F has not been examined to ascertain its chemical and ballistic properties, but there is a strong probability that these do not differ greatly from those of the PzKw 3, Model J.
The Panzer IV Aus.F, seen here in the Army Group North sector during the summer of 1942, was the last of the short barrelled tanks to see action.
(4) Model G
This model which mounts the long 75-mm gun, Kw.K 40, was first encountered in June 1942. It is reported from the Middle East that its armour is the same as that of Model F; namely 1.96 inches on the front, and 30 mm (1.18 inches) on the sides.
In addition to the increase in armor it was necessary to up-gun the tank by introducing a high velocity main armament which gave the Panzer IV its tank killing power. Not surprisingly the Allies were soon aware of this development and the intelligence was quickly spread through the regular channels.