Tuesday, August 11, 2015

Cutaway - Pz.III

The Panzer III crew consisted of five men with two in the front of the hull including a driver at the left and a radio operator/hull machine gunner at the right. Up in the turret, the gunner sat to the left of the main weapon in typical German style, a loader worked the gun on the right side, and the commander sat elevated at the rear with the use of a cupola over his head for battlefield observation. Both the gunner and commander sat in padded seats suspended from the turret ring, rotating with the gun. But the loader had the use of a small fold down seat attached to the back firewall and typically worked standing up on the hull floor with his seat stowed. Most of these Ausf. E and F panzers were manufactured between 1938 and 1940 by Daimler-Benz, Maschinenfabrik-Augsburg-Nuernberg (MAN), and Henschel & Sohn, and together these firms produced 96 Ausf. E and 435 Ausf. F vehicles. The basic interior layout of the Pz. III would remain unchanged throughout the remainder of the production run but most of the major components would continue to improve, particularly up in the turret, as experience was gained in combat.

Unlike the early 3.7cm gun, the 5cm weapon and coax were protected behind an external mantlet. But in these models there were two viewing flaps in the mantlet, one on each end, and both of them are visible here. The additional right flap allowed the loader the same unrestricted view out the front of the tank as the gunner had. Notice the lead weight attached to the rear of the recoil guard to help balance the barrel heavy weapon.

The 5cm gun fired three ammo types. The high explosive (HE) was known as Sprenggranate 38 (Sprgr. 38), which was nose fused for impact detonation. The second type was an armor piercing capped shell of the typical German penetrating and bursting type called Panzergranate 39 (Pzgr. 39). The piercing cap on the end of the projectile helped reduce shattering upon contact with the target. The third type was Panzergranate 40 (Pzgr. 40) and this was a light weight projectile with a very heavy tungsten carbide core. Sometimes known as armor piercing composite rigid (APCR), this projectile reached a very high muzzle velocity at close ranges due to its light weight, but its velocity decreased rapidly at distance for the same reason. Because tungsten was at a premium in Germany, this shell was never offered to tankers in abundant quantity, but when battling at close quarters the Pzgr. 40 was a powerful armor piercing shot.

The Pzgr. 39 was one of a number of German bursting AP shells (called "Supercharged" by the Allies) which were particularly effective against Allied tanks where ammo was often stored unprotected inside the hull or turret. This was because the Pzgr. bursting charge detonated just after penetration, causing extensive internal fires and ammunition explosions with subsequent serious injury or death to the crew. On the other hand, Panzer III ammo rounds were stored in armored cabinets (4 to 6mm thick) below the turret ring, and Allied AP rounds that managed to penetrate the external armor skin were less likely to set them off. This was because the damage caused by most allied solid AP shells was restricted to the kinetic energy left in the round after penetration.

The next major changes in the evolution of the Pz. III centered on yet another increase in armor thickness to 30mm, requiring a new driver's visor 30 and an improved KFF2 periscope in the new Ausf. G tanks. With an improvement in the turret wall design to provide more room inside, an improved cupola was also added, the same cupola that was also mounted on later Pz. IV tanks. As with the mid production cupola mentioned earlier, the late style cupola required only one lever to open and close the upper and lower shutters that protected each of the cupola's five viewing blocks. But now the shutters were smaller, only the width of the view opening, and the operating lever inside was made to fit into détentes that fixed the shutters fully opened, half opened, and fully closed. Although the first batches of these new Ausf. G and J tanks were originally built with the 3.7cm guns, all later vehicles of these types were fitted with the KwK38 L/42 5cm weapons. By the end of 1942, most of the earlier Panzer III tanks that were still in service had been updated with the 5.0cm gun and very few photos show vehicles with the smaller caliber weapon from then on.

The short barreled 5.0cm L/42 was not powerful enough to penetrate many of the Soviet tanks they encountered during their Blitz into Russia and the longer KwK39 L/60 gun was substituted for the shorter weapon at the factories during the Ausf. J production run. Although the gun breech of both the L/42 and L/60 guns is identical from inside the vehicle, the longer ammo rounds of the later gun required some rearranging of storage in the hull and a reduction of numbers. Those vehicles with hull side escape hatches could store around 84 of these longer rounds while later Ausfs., with the hatches deleted, had room for 98.