Panther Tank

Panther is the common name of a medium tank fielded by Nazi Germany in World War II that served from mid-1943 to the end of the European war in 1945. It was intended as a counter to the T-34, and to replace the Panzer III and Panzer IV; while never replacing the latter, it served alongside it as well as the heavier Tiger tanks until the end of the war. The Panther's excellent combination of firepower, mobility, and protection served as a benchmark for other nations' late war and immediate post-war tank designs, and it is frequently regarded as one of the best tank designs of World War II.

Until 1944, it was designated as the Panzerkampfwagen V Panther and had the ordnance inventory designation of Sd.Kfz. 171. On 27 February 1944, Hitler ordered that the Roman numeral V be deleted from the designation.

The Panther tank was a compromise of various requirements. While sharing essentially the same engine as the Tiger I tank, it had better frontal armor, better gun penetration, was lighter overall and thus faster, and could handle rough terrain better than the Tigers. The tradeoff was weaker side armor; the Panther proved to be deadly in open country and shooting from long range, but vulnerable to close-quarters combat. Also, the 75 mm gun fired a slightly smaller shell than the Tiger's 88 mm gun, providing less high explosive firepower against infantry, though it was still quite effective.

The Panther was also far cheaper to produce than the Tiger tanks, and only slightly more expensive than the Panzer IV, as its design came to fruition at the same time that the Reich Ministry of Armament and War Production was making great efforts to increase war production. Key elements of the Panther design, such as its armor, transmission and final drive, were compromises made specifically to improve production rates and address Germany's war shortages, whereas other elements such as its highly compact engine and its complex suspension system remained with their elegant but complicated engineering. The result was that Panther tank production was far higher than was possible for the Tiger tanks, but not much higher than had been accomplished with the Panzer IV. At the same time, the simplified final drive became the single major cause of breakdowns of the Panther tank, and was a problem that was never corrected.

The Panther tank arrived in 1943 at a crucial phase in World War II for Germany. Rushed into combat at the Battle of Kursk before its teething problems were corrected, the Panther tank thereafter fought outnumbered in Germany's steady retreat before the Allies for the remainder of World War II. Its success as a battlefield weapon was thus hampered by Germany's generally declining position in the war, with the loss of airpower protection by the Luftwaffe, the loss of fuel and training space, and the declining quality of tank crews. Nevertheless, the Panther tank was respected by the Allies, and its combat capabilities led directly to the introduction of heavier Allied tanks such as the Soviet IS-2 and the American M26 Pershing into the war.

Panther
Type	Medium tank
Place of origin	Nazi Germany
Service history
In service	1943–1945 (Nazi Germany)
Used by	Nazi Germany (main user) France (a few captured) Soviet Union (a few captured) Romania (~21 post war) Bulgaria (a few captured) Hungary (a few captured)
Wars	World War II
Production history
Designer	MAN AG
Designed	1942
Manufacturer	initially to be built by MAN in Nürnberg, Daimler-Benz in Berlin-Marienfelde, Maschinenfabrik Niedersachsen Hannover (MNH) in Hannover, and Henschel & Sohn in Kassel.
Unit cost	Ausf. D initial contract unit cost RM 117,100 (excluding armament)
Produced	1942–1945
Number built	about 6,000
Specifications
Weight	44.8 tonnes (44.1 long tons; 49.4 short tons)
Length	6.87 metres (22 ft 6 in) 8.66 metres (28 ft 5 in) gun forward
Width	3.27 metres (10 ft 9 in) 3.42 metres (11 ft 3 in) with skirts
Height	2.99 metres (9 ft 10 in)
Crew	5 (Driver, radio-operator/hull machine gunner, commander, gunner, loader)
Armor	15–120 mm (0.59–4.7 in)
Main armament	1 × 7.5 cm KwK 42 L/70 79 rounds
Secondary armament	2 × 7.92 mm Maschinengewehr 34 5,100 rounds
Engine	V-12 petrol Maybach HL230 P30 700 PS (690 hp, 515 kW)
Power/weight	15.39 PS/tonne (13.77 hp/ton)
Transmission	ZF AK 7-200. 7 forward 1 reverse
Suspension	double torsion bar, interleaved road wheels
Operational range	250 km (160 mi)
Speed	55 km/h (34 mph) (first models), 46 km/h (29 mph) (later models)

The weight of the production model was increased to 45 metric tons from the original plans for a 35 ton tank. Hitler had personally reviewed the final designs and insisted on an increase in the thickness of the frontal armor - the front glacis plate was increased from 60 mm (2.4 in) to 80 mm (3.1 in) and the turret front plate was increased from 80mm to 100 mm (3.9 in).

The Panther was rushed into combat before all of its teething problems were corrected. Reliability was considerably improved over time, and the Panther did prove to be a very effective fighting vehicle; however, some design flaws, such as its weak final drive units, were never corrected due to various shortages in German war production.

The crew was made up of five members: driver, radio operator (who also fired the bow machine gun), gunner, loader, and commander.

Engine

The first 250 Panthers were powered by a Maybach HL 210 P30 engine, V-12 gasoline engine which delivered 650 metric hp at 3,000 rpm and had three simple air filters. Starting in May 1943, the Panthers were built using the 700 PS (690 hp, 515 kW)/3000 rpm, 23.1 litre Maybach HL 230 P30 V-12 gasoline engine. The light alloy block used in the HL 210 was replaced by a cast iron block to save aluminum. Two multistage "cyclone" air filters were used to automate some of the dust removal process. In practice the engine power output was reduced due to the use of low quality gasoline. With a capacity of 190 US gallons of fuel, a Panther could operate 60–80 mi (97–130 km) on roads and 40–50 mi (64–80 km) cross country

The HL 230 P30 engine was a very compact design, which kept the space between the cylinder walls to a minimum. The crankshaft was composed of seven discs, each with an outer race of roller bearings, and a crankshaft pin between each disc. To reduce the length of the engine further, by one half a cylinder diameter, the two banks of 6 cylinders of the V-12 were not offset - the center points of the connecting rods of each cylinder pair in the "V" where they joined the crankshaft pin were thus at the same spot rather than offset; to accommodate this arrangement, one connecting rod in the pair of cylinders was forked and fit around the other "solid" connecting rod at the crankshaft pin. (A more typical "V" engine would have had offset cylinder banks and each pair of connecting rods would have fit simply side by side on the crankshaft pin). This compact arrangement with the connecting rods was the source of considerable teething problems early on. Blown head gaskets were another problem, which was corrected with improved seals in September 1943. Improved bearings were introduced in November 1943 to replace the faulty ones that had failed frequently. An engine governor was also added in November 1943 that reduced the maximum engine speed to 2500 rpm. An eighth crankshaft bearing was added beginning in January 1944 to help reduce motor failures.

The engine compartment space was designed to be watertight so that the Panther could be submerged and cross waterways. The result was that the engine compartment was poorly ventilated and prone to overheating. The fuel connectors in the early models were non-insulated, leading to leakage of fuel fumes into the engine compartment. This led to many engine fires in the early Panthers. Additional ventilation was added to draw off these gasses, which mitigated but did not completely solve the problem of engine fires. Other measures taken to reduce this problem included improving the coolant circulation inside the motor and adding a reinforced membrane spring to the fuel pump. The Panther had a solid firewall separating the engine compartment and the fighting compartment to keep engine fires from spreading.

The engine became more reliable over time. A French assessment of their stock of captured Panthers in 1947 concluded that the engine had an average life of 1,000 km (620 mi) and maximum life of 1,500 km (930 mi).

Suspension

The suspension consisted of front drive sprockets, rear idlers and eight double-interleaved rubber-rimmed steel road wheels on each side, suspended on a dual torsion bar suspension. The dual torsion bar system, designed by Professor Ernst Lehr, allowed for a wide travel stroke and rapid oscillations with high reliability, thus allowing for relatively high speed travel by this heavy tank over undulating terrain. However, the extra space required for the bars running across the length of the bottom of the hull, below the turret basket, increased the overall height of the tank and also prevented an escape hatch in the hull bottom. When damaged by mines, the torsion bars often required a welding torch for removal.

The Panther's suspension was complicated to manufacture and the interleaved system made replacing inner road wheels time consuming. The interleaved wheels also had a tendency to become clogged with mud, rocks and ice, and could freeze solid overnight in the harsh winter weather of the Eastern Front. Shell damage could also cause the road wheels to jam together and become extremely difficult to separate. Interleaved wheels had long been standard on all German half-tracks. The extra wheels did provide better flotation and stability, and also provided more armor protection for the thin hull sides than smaller wheels or non-interleaved wheel systems, but the complexity meant that no other country ever adopted this design for their tanks. In September 1944, and again in March/April 1945, M.A.N. built a limited number of Panther tanks with steel roadwheels originally designed for the Tiger II and late series Tiger I tanks. Steel roadwheels were introduced from chassis number 121052 due to raw material constraints.

From November 1944 through February 1945, a conversion process began to use sleeve bearings in the Panther tank, as there was a shortage of ball bearings. The sleeve bearings were primarily used in the running gear; plans were made also to convert the transmission to sleeve bearings, but were not carried out as production of Panther tanks came to an end.

Steering and transmission

Steering was accomplished through a seven-speed AK 7-200 synchromesh gearbox, designed by Zahnradfabrik Friedrichshafen, and a MAN single radius steering system, operated by steering levers. Each gear had a fixed radius of turning, ranging from five meters for 1st gear up to 80 meters for 7th gear. The driver was expected to judge the sharpness of a turn ahead of time and shift into the appropriate gear to turn the tank. The driver could also engage the brakes on one side to force a sharper turn. This manual steering was a much simplified design, compared to the more sophisticated dual-radius hydraulically controlled steering system of the Tiger tanks.

The AK 7-200 transmission was also capable of pivot turns, but this method of turning could accelerate failures of the final drive.

Throughout its career, the weakest parts were its final drive units. The problems were from a combination of factors. The original MAN proposal had called for the Panther to have an epicyclic gearing (hollow spur) system in the final drive, similar to that used in the Tiger I. However, Germany at the time suffered from a shortage of gear-cutting machine tools and, unlike the Tiger tanks, the Panther was intended to be produced in large numbers. To achieve the goal of higher production rates, numerous simplifications were made to the design and its manufacture. This process was aggressively pushed forward, sometimes against the wishes of designers and army officers, by the Chief Director of Armament and War Production, Karl-Otto Saur (who worked under, and later succeeded, Reichminister Speer). Consequently, the final drive was changed to a double spur system. Although much simpler to produce, the double spur gears had inherently higher internal impact and stress loads, making them prone to failure under the high torque requirements of the heavy Panther tank. Furthermore, high quality steel intended for double spur system was not available for mass production, and was replaced by 37MnSi5 tempered steel, which was unsuitable for high-stress gear. In contrast, both the Tiger II and the US M4 Sherman tank had double helical (herringbone gears) in their final drives, a system that reduced internal stress loads and was less complex than epicyclic gears.

Compounding these problems was the fact that the final drive's housing and gear mountings were too weak because of the type of steel used and/or the tight space allotted for the final drive. The final gear mountings deformed easily under the high torque and stress loads, pushing the gears out of alignment and resulting in failure. Due to the weakness of the final drives their average fatigue life was only 150 km. In Normandy, about half of the abandoned Panthers were found by the French to have broken final drives. However, at least the final gear housing was eventually replaced with stronger one, while final gear problem was never solved.

Plans were made to replace the final drive, either with a version of the original epicyclic gears planned by MAN, or with the final drive of the Tiger II. These plans were intertwined with the planning for the Panther II, which never came to fruition because Panzer Commission deemed that temporary drop in production of Panther due to merger of Tiger II and Panther II was unacceptable. It was estimated that building the epicyclic gear final drive would have required 2.2 times more machining work than double spur gears, and this would have affected manufacturing output.

Most of the shortcomings were considered acceptable once design flaws were rectified. Due to the mechanical unreliability of final gear Panther must be driven with care, a characteristic shared with the Tiger tanks as well as Jagdtigers. Long road marches would result in a significant number of losses due to breakdowns, and so the German Army had to ship the tanks by rail as close to the battlefield as possible.

Armor

Initial production Panthers had a face-hardened glacis plate (the main front hull armor piece), but as armor-piercing capped rounds became the standard in all armies (thus defeating the benefits of face-hardening, which caused uncapped rounds to shatter), this requirement was deleted on March 30, 1943. By August 1943, Panthers were being built only with a homogeneous steel glacis plate. The front hull had 80 mm of armor sloped back at 55 degrees from the vertical, welded but also interlocked for strength. The combination of a steep slope and thick armor meant that few Allied or Soviet weapons could penetrate this part of the tank.

The armor for the side hull and superstructure (the side sponsons) was much thinner (40–50 mm). The thinner side armor was necessary to keep the overall weight within reasonable bounds, but it made the Panther vulnerable to attacks from the side by most Allied and Soviet tank and anti-tank guns. German tactical doctrine for the use of the Panther thus emphasized the importance of flank protection. Five millimeter thick skirt armor, known as Schürzen, intended to provide protection for the lower side hull from Soviet anti-tank rifle fire was fitted on the hull side. Zimmerit coating against magnetic mines started to be applied at the factory on late Ausf D models beginning in September 1943; an order for field units to apply Zimmerit to older versions of the Panther was issued in November 1943. In September 1944, orders to stop all application of Zimmerit were issued, based on rumors that hits on the Zimmerit had caused vehicle fires.

Panther crews were aware of the weak side armor and made unauthorized augmentations by hanging track links or spare roadwheels onto the turret and/or the hull sides. The rear hull top armor was only 16 mm thick, and had two radiator fans and four air intake louvres over the engine compartment that were vulnerable to strafing by aircraft.

As the war progressed, Germany was forced to reduce or no longer use certain critical alloy materials in the production of armor plate, such as nickel, tungsten, molybdenum, and manganese; this did result in lower impact resistance levels compared to earlier armor. Manganese from mines in the Ukraine ceased when the German Army lost control of this territory in February 1944. Allied bombers struck the Knabe mine in Norway and stopped a key source of molybdenum; other supplies from Finland and Japan were also cut off. The loss of molybdenum, and its replacement with other substitutes to maintain hardness, as well as a general loss of quality control resulted in an increased brittleness in German armor plate, which developed a tendency to fracture when struck with a shell. Testing by U.S. Army officers in August 1944 in Isigny, France showed catastrophic cracking of the armor plate on two out of three Panthers examined.

Armament

The main gun was a 7.5 cm Rheinmetall-Borsig KwK 42 (L/70) with semi-automatic shell ejection and a supply of 79 rounds (82 on Ausf. G). The main gun used three different types of ammunition: APCBC-HE (Pzgr. 39/42), HE (Sprgr. 42) and APCR (Pzgr. 40/42), the last of which was usually in short supply. While it was of only average caliber for its time, the Panther's gun was one of the most powerful tank guns of World War II, due to the large propellant charge and the long barrel, which gave it a very high muzzle velocity and excellent armor-piercing qualities. The flat trajectory also made hitting targets much easier, since accuracy was less sensitive to range. The Panther's 75 mm gun had more penetrating power than the main gun of the Tiger I heavy tank, the 8.8 cm KwK 36 L/56, although the larger 88 mm projectile might inflict more damage if it did penetrate.

The tank typically had two MG 34 machine guns of a specific version designed for use in armored combat vehicles featuring an armored barrel sleeve. An MG 34 machine gun was located co-axially with the main gun on the gun mantlet; an identical MG 34 was located on the glacis plate and fired by the radio operator. Initial Ausf. D and early Ausf. A models used a "letterbox" flap opening, through which the machine gun was fired. In later Ausf A and all Ausf G models (starting in late November-early December 1943), a ball mount in the glacis plate with a K.Z.F.2 machine gun sight was installed for the hull machine gun.

Turret

The front of the turret was a curved 100 mm thick cast armor mantlet. Its transverse-cylindrical shape meant that it was more likely to deflect shells, but the lower section created a shot trap. If a non-penetrating hit bounced downwards off its lower section, it could penetrate the thin forward hull roof armor, and plunge down into the front hull compartment. Penetrations of this nature could have catastrophic results, since the compartment housed the driver and radio operator sitting along both sides of the massive gearbox and steering unit; more importantly, four magazines containing main gun ammunition were located between the driver/radio operator seats and the turret, directly underneath the gun mantlet when the turret was facing forward.

From September 1944, a slightly redesigned mantlet with a flattened and much thicker lower "chin" design started to be fitted to Panther Ausf G models, the chin being intended to prevent such deflections. Conversion to the "chin" design was gradual, and Panthers continued to be produced to the end of the war with the rounded gun mantlet.

In most cases the Panther's gun mantlet could not be penetrated by the M4s 75 mm gun, the T-34s 76.2 mm gun, or the T-34-85s 85 mm gun. But it could be penetrated by well-aimed shots at 100 m by the 76mm M1A1 gun used on certain models of the M4, at 500 m by the Soviet A-19 122 mm gun on the IS-2 and at over 2500 yards (2286 m) by the British Ordnance QF 17 pounder using APDS ammunition. The side turret armor of 45 mm (1.8 in) was vulnerable to penetration at long range by almost all Allied tank guns, including the M4's 75 mm gun which could penetrate it at 1,500 m (0.93 mi). These were the main reasons for continued work on a redesigned Panther turret, the Schmalturm.

The Ausf A model introduced a new cast armor commander's cupola, replacing the more difficult to manufacture forged cupola. It featured a steel hoop to which a third MG 34 or either the coaxial or the bow machine gun could be mounted for use in the anti-aircraft role, though it was rare for this to be used in actual combat situations.

The first Panthers (Ausf D) had a hydraulic motor that could traverse the turret at a maximum rate of one complete revolution in one minute, independent of engine speed. This slow speed was improved in the Ausf A model with a hydraulic traverse that varied with engine speed; one full turn taking 46 seconds at an engine speed of 1,000 rpm but only 15 seconds if the engine was running at 3,000 rpm. This arrangement was a slight weakness, as traversing the Panther's turret rapidly onto a target required close coordination between the gunner and driver who had to run the engine to maximum speed. By comparison, the turret of the M4 Sherman turret traversed at up to 360 degrees in 15 seconds and was independent of engine speed, which gave it an advantage over the Panther in close-quarters combat. As usual for tanks of the period, a hand traverse wheel was provided for the Panther gunner to make fine adjustment of his aim.

Ammunition storage

Ammunition storage for the main gun was a weak point. All the ammunition for the main armament was stored in the hull, with a significant amount stored in the sponsons. In the Ausf D and A models, 18 rounds were stored next to the turret on each side, for a total of 36 rounds. In the Ausf G, which had deeper sponsons, 24 rounds were stored on each side of the turret, for a total of 48 rounds. In all models, 4 rounds were also stored in the left sponson between the driver and the turret. An additional 36 rounds were stored inside the hull of the Ausf D and A models - 27 in the forward hull compartment directly underneath the mantlet. In the Ausf G, the hull ammunition storage was reduced to 27 rounds total, with 18 rounds in the forward hull compartment. For all models, 3 rounds were kept under the turntable of the turret. The thin side armor could be penetrated at combat ranges by many Allied tank guns, and this meant that the Panther was vulnerable to catastrophic ammunition fires ("brewing up") if hit from the sides.

The loader was stationed in the right side of the turret. With the turret facing forward, he had access only to the right sponson and hull ammunition, and so these served as the main ready-ammunition bins.