Second Fiddle

Even though the German Pz.Kpfw.IV tank was originally created as a support vehicle (Begleitwagen) and fell short of its counterpart the Pz.Kpfw.III in many ways, it was still the heaviest tank in the German arsenal and mounted the largest caliber gun. Issues with Pz.Kpfw.III production also made it the most numerous German medium tank at the start of WWII. Despite its “secondary” designation, the Pz.Kpfw.IV did not evade the attention of the British. Intelligence agents and tankers alike strived to uncover its secrets.

As with the Pz.Kpfw.III, the British only knew about the Pz.Kpfw.IV from rumours. There was little verified information, but one of the few things known for sure was that the tank was heavier than the Pz.Kpfw.III. Intelligence summaries referred to it as a medium tank, whereas the Pz.Kpfw.III was called a “medium-light tank”. Naturally, the British encountered the Pz.Kpfw.IV in France in 1940, but a sample could not be obtained for study due to the rapid defeat of the British Expeditionary Force. Even though there was no precise data about the armour or armament of the tank, an identification poster was still composed and distributed on December 16th, 1940.

As active combat against the Germans ceased, no information was received about the new German tank for some time. In March of 1941 a “reliable source” reported on the appearance of the “type IVa” tank. British intelligence decided that this was a commander’s tank on the Pz.Kpfw.IV chassis, but there was no additional data to confirm or deny this theory. The lack of information about one of the enemy’s newest tanks was worrying, as British tankers would no doubt run into a foe that they knew nothing about.

The Pz.Kpfw.IV showed up again in North Africa. The Afrika Korps had two divisions with this type of tank in their ranks: the 5th Light Division and 15th Tank Division. These divisions went into battle towards the end of March of 1941 with 49 Pz.Kpfw.IV tanks among others. There were fewer of them than Pz.Kpfw.III.

It didn’t take long for the British to obtain their first trophies. A disabled Pz.Kpfw.IV tank was inspected in early May. The tank had 30 mm thick armour in the front of the hull and turret. The sides and commander’s cupola were 20 mm thick. The rear and roof were 10 mm thick. The front of the hull had a 30 mm thick applique plate attached and the sides were partially protected by 20 mm thick applique armour. The turret had no applique armour attached.

The armament consisted of one 75 mm gun and two “7.91 mm Spandau machine guns”. The tank carried 83 rounds for its main gun. British specialists evaluated the quality of the armour as poor, even worse than that of Czech tanks. Intelligence noted that the Germans might be withholding higher quality armour to build heavier tanks. A Boys rifle was capable of penetrating 25 mm of armour of this quality from 450 yards (410 m), which meant that the tank was vulnerable to this weapon from the side. Quality of weld seams was also poor, it was noted that they could crack even under rifle fire.

The British estimated the tank’s top speed at 37 kph. According to their calculations, the tank would be able to cross a 3.2 meter wide anti-tank ditch or climb a 68 cm tall wall. The cruising range was estimated at 120 km, although the report does admit that this could be an overestimation.

A 2-pounder gun mounted on a Cruiser Tank Mk.IVA was tested against another captured Pz.Kpfw.IV in mid-June. Armour piercing shot punched through the side armour and came out of the opposite side of the tank at ranges of 500-700 yards (460-640 meters). From 1100 yards (1000 meters) the shot penetrated the tank’s side but was unable to penetrate the opposite side. The front armour was tougher; when firing on the section with applique armour from 500 yards only five shots out of six penetrated. At this range the 2-pounder easily penetrated the front of the turret that was not protected by additional armour. Three projectiles broke up inside the tank and two more penetrated the front of the turret and came out of the back. At 700 yards the front was penetrated and the shot left 10-15 mm deep gouges in the rear wall. The front armour could still be penetrated at a range of 1100 yards.

The report also covered the use of No.74 grenades (sticky bombs) against the tank in combat. Such a grenade would not disable the tank when thrown, but the tank could be destroyed with one if it was well placed. For instance, British scouts managed to find a lone Pz.Kpfw.IV in the desert, take its crew prisoner, and demolish the tank by placing sticky bombs on the engine deck.

The British theorized that applique armour was added to the Pz.Kpfw.IV after the Germans studied captured 2-pounder guns in France. The applique armour may have protected the tanks against early 2-pounder shells, but the new type of solid shot left the Germans no chance. The same report also gave a revised speed of the Pz.Kpfw.IV as 25 kph (this limit was marked on the speedometer) when driving on its own and 15 kph as a part of a column of vehicles.

It wasn’t long before the British got their hands on a running Pz.Kpfw.IV. The tank was delivered to the Experimental Wing of the School of Tank Technology on November 3rd, 1941. It was in quite good condition when it was captured during the Battle of Tobruk, but the ship carrying the tank to Britain was hit by the Luftwaffe en route. As a result, the tank was delivered not only with battle damage, but with damage from fire, sea water, and fire extinguisher fluid. Mobility trials were out of the question. Only measurements and inspections were possible.

Weighing the tank gave a mass of 22 tons, which was close to intelligence estimates. Specialists composed a detailed description of the hull, transmission, engine, armament, and especially the suspension. The description also mentioned that up to 30 spare track links and two road wheels were carried on the fenders of these tanks. The British made special note of the conical bulletproof bolts.

The description was largely neutral and did not classify most aspects of the tank as good or bad, but there were some exceptions. The inspector noted that the turret traverse motor only had one speed and was very bulky. The fighting compartment was also very small, just 1.3 meters in height. The commander’s cupola design was criticized, among the other vision facilities. The tank had a total of 13 observation devices, but quantity did not equal quality. They were so badly placed that the tank’s crew was blind in three directions when buttoned up. Only the driver and radio operator had decent visibility forward, but they could not see anything on their flanks. The commander could use his cupola to look around, but it had considerable blind spots.

The 64-inch (162 cm) wide turret ring received praise. This was wider than any British tank. Inspectors also noted that the tank was assembled exclusively by welding. The tank had no applique armour. The thickness of its front armour was estimated at 35 mm.

The captured Pz.Kpfw.IV tank was sent to the Leyland Motors factory after the study was finished, where it underwent lengthy repairs. According to documents, this tank was eventually restored. It was given a Department of Tank Design registration number (3010) and retained by the School of Tank Technology. On July 9th, 1942, it took part in a captured vehicle parade. The tank remained in running order until at least May 1st, 1945.

A quiet period followed. Inspection of captured German vehicles revealed no new information. Front line troops noted that these tanks burned easily, even compared to other German tanks. Penetration of the fighting compartment was guaranteed to result in a forceful detonation of the tank’s ammunition. Six destroyed tanks were inspected in January of 1942. As they were severely damaged, British inspectors could climb inside and take measurements of internal components.

Inspection showed that the fuel tanks were located underneath the fighting compartment and protected with 5 mm thick armour. The floor was 10 mm thick and the sides were 22 mm thick. 20 mm thick plates were welded on the side of one of the tanks to protect the final drives. Another tank had the same modification, the only one of the six with 30 mm thick applique plates. The plates were cut much rougher than seen on earlier vehicles. The same report stated that according to captured German documents the Pz.Kpfw.IV was more reliable than the Pz.Kpfw.III.

A few weeks later the Pz.Kpfw.IV was once again a topic in intelligence summaries. A new variant of this tank was discovered. The front and side of the superstructure still had applique armour, but the front hull was now made out of a single 50 mm thick plate. One captured tank was retained for study, two more were sent to the US.

A driver’s observation device (presumably from one of these three tanks) was also described in the report. It received a very poor evaluation. According to the British, the 10.5 kg binocular sight was very awkward to use, complex, and expensive. Despite the complexity of the design it could not be tilted up and down to improve the range of vision like British observation devices.

The new tank was sent to Farnborough where it was inspected by British specialists. A report on this tank was published in November of 1942. The tank can clearly be identified as a Pz.Kpfw.IV Ausf.E from the description, although it is still called just “Pz.Kw.4”. The tank arrived in rather poor condition. The hull had many holes and one track was severed. The vehicle was initially immobilized by three shots to the rear, presumably from 2-pounders. The machine guns, telescopic sight, ammunition, and other components were missing. The tank weighed 19.3 tons. British inspectors estimated that with the missing equipment it would weigh 22 tons, the same as the other Pz.Kpfw.IV.

The armament was the same as on the previous variants. The 7.5 cm KwK gun had a maximum elevation angle of 21 degrees and depression of -11 degrees. The full range of elevation could be covered with 15 turns of the elevation flywheel. The British once again noted that the turret was assembled exclusively with welding. The turret roof was made out of one plate that was bent in the middle in order to avoid an unnecessary joint. An electric exhaust fan was installed on the right side of the roof and a signal hatch was located on the left. A commander’s cupola was installed in the center rear on a 48 cm wide base. It seemed that the Germans experienced high casualties among commanders, as the cupola armour increased from just 20 mm to 50-95 mm. The glass in the observation slits was missing, so no conclusions could be made about it.

The turret could be turned by hand (180 turns of the flywheel were required to traverse it fully) or using an electric motor powered by a secondary gasoline engine with a separate 9.5 L fuel tank. The turret was 180 cm wide. Inspectors noted that the turret ring and the fighting compartment were made as wide as possible. This made the tank roomy, but had a side effect: it was impossible to protect the turret ring from splash.

The tank’s ammunition racks were destroyed, and so it was impossible to establish the exact number of rounds carried on board. The British estimated that the tank carried about 105 75 mm rounds.

This report also covered the applique armour. The armour on the front of the superstructure was installed with a slight gap, although this was likely built this way for ease of manufacture rather than for ballistic reasons. The applique armour was held on with hexagonal bulletproof bolts. The bolts were quite brittle and after 2-3 hits the applique armour fell off. The armour hardness of the tank ranged between 270 and 350 BNH. None of the armour was surface hardened. The 50 mm plate had several gouges on it from 2-pounder fire. It seemed that the Germans welded a patch over one of the gouges, but it later fell off. According to British inspectors, this was due to the poor quality of welding. Other evidence of repairs was found, including a hinge transplanted from a Pz.Kpfw.III tank.

Descriptions of the engine and suspension were brief, as there were no new features to be found here. The tank was indeed more reliable than the Pz.Kpfw.III, as the odometer read 4465 km, more than any Pz.Kpfw.III tank was expected to travel.

Information that allowed the British to figure out the different models of the Pz.Kpfw.IV was obtained only by late 1942. The various letter indexes finally became known. There was no information about the old Ausf.A, B, and C. The British assumed that these tanks had the same armour as the Ausf.D, the first Pz.Kpfw.IV tank that they had a chance to inspect.

The tank was modernized in 1941. 30 mm of armour was added to the front and 20 mm to the sides. The Ausf.E variant had 50 mm thick hull armour, but the armour of the superstructure varied. There were tanks with just one piece of applique armour around the machine gun port, two pieces (one around the machine gun and one around the driver’s vision port) or even three (the armour around the driver’s port was composed of two pieces). There were vehicles of this type with no applique armour at all.

The applique armour was surface hardened. Unlike the various types of armour discovered on the front of the superstructure, the side applique plates were always the same. They were made from homogeneous armour with a hardness of about 370 BNH. The Pz.Kpfw.IV did not have spaced armour like the type used on the Pz.Kpfw.III tanks. In turn, the Pz.Kpfw.III had no additional armour on the sides. The two tanks were similar but developed in unique ways.

The British also found out about the Pz.Kpfw.IV Ausf.F. This tank was similar to the Pz.Kpfw.III with 50 mm thick front armour (turret, hull, and superstructure) and 30 mm thick sides. No visually distinguishing features are listed in the report. This tank was not studied in detail, but it was assumed that the composition of the armour was no different than a Pz.Kpfw.III Ausf.J.

The tank’s gun was called “7.5 cm KwK” in British documents, or “7.5 cm KwK (short)” after long 75 mm guns were discovered. Four types of shells were known: APCBC, HE, HEAT, and smoke. The 6.7 kg APCBC shell with a muzzle velocity of just 386 m/s penetrated 45 mm of armour at normal from 500 yards (460 meters). This was enough to combat only the lightest British vehicles. The HEAT shell penetrated up to 55 mm of armour, but it was very rare. Pz.Kpfw.IV tanks inspected on the battlefield chiefly carried HE ammunition. This ammunition was incapable of breaking through the armour of a Valentine tank, but a direct hit could disable the running gear and immobilize it.

The gun was aimed with a 2.4x T.Z.F.5b monocular sight. The sight had markings for the cannon up to 2000 m and for the machine gun up to 800 m. The field of view was 23.5 degrees wide, but the picture became blurrier the further it was away from the center. British inspectors estimated that the usable view angle was only 8 degrees. The picture was also very dim, as the sight transmitted only 20% of incoming light.

Trials of the turret traverse motor were held on July 26th, 1943, presumably using the repaired Pz.Kpfw.IV Ausf.D tank. According to the testers, the traverse motor did not allow the gun to be aimed precisely and trying to track a target led to “exhaustion and pain” for the gunner. The traverse mechanism handle was considered unsatisfactory. The switch to between the manual and electric traverse was difficult to use. There was a noticeable jerk at the beginning of the traversing process. The top traverse speed was low, but the acceleration was better than on British tanks with electric turret traverse.

It was difficult to switch the direction of traverse, plus the turret jumped even harder after a switch than when traversing in one direction. This operation could also be fatal for the mechanism. When the turret traverse direction was changed while the tank was standing on an 8 degree slope the traverse motor clutch broke and trials had to end prematurely.

The hand traverse was very heavy, but allowed for more precise aiming than British equivalents. This advantage was meaningless when the tank was standing on a slope, as at just a 7.5 degree tilt the gunner no longer had enough strength to traverse the turret.

Overall, the design of the electrically powered traverse was considered worse than the British hydraulic type, but better than the electric type in some respects. Because of the extreme difficulty in traversing the turret at even a slight incline, British testers doubted that the tank could turn its turret on the move. Nevertheless, the design had potential, and the testers even recommended that it should be tested with a British style handle.

The British were not very impressed with the Pz.Kpfw.IV. This was the largest and heavier known German tank, but its armour was very weak, especially compared to other vehicles in its class. Even the applique armour was not enough to save it from 2-pounder guns, let alone more powerful weapons. The armament was not particularly impressive either. The short 7.5 cm KwK was inferior to the American 75 mm M2 in every way.

British specialists noted that the design of the tank did not change radically over the course of nearly two years and even predicted that it would be removed from production and replaced with the superior (according to them) StuG III assault gun. This lack of interest is reflected in the lists of recovered German tanks. As of May 1st, 1945, there were only four Pz.Kpfw.IV tanks delivered to the Department of Tank Design and only one of them was in running condition, compared to eleven Pz.Kpfw.III (with six running) which doesn’t even include StuGs and other vehicles on the Pz.Kpfw.III’s chassis. However, the Germans were not sitting idle. The modernization reserve of the Pz.Kpfw.IV was not fully exhausted and the tank continued to evolve.

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This article was originally published on Warspot.net.