- CHAPTER 9 -
The cost of a Panther tank was 117,100 Reichmarks (RM). This compared favourably with 82,500 RM for the StuG III, 96,163 RM for the Panzer III, 103,462 RM for the Panzer IV, and 250,800 RM for the Tiger I. These figures did not include the cost of the armament and radio. Expressed in terms of Reichmarks per ton the Panther tank was arguably one of the most cost-effective German tanks of World War II. However, these cost figures should be understood in the context of the time period in which the various tanks were first designed, as the Germans armaments industry increasingly strove for designs and production methods that would allow for higher production rates, and thereby steadily reduced the cost of their tanks.
The process of streamlining the production of German tanks first began after Speer became Reichminister in early 1942, and steadily accelerated through 1943 reaching a peak in 1944; production of the Panther tank therefore coincided with this period of increased manufacturing efficiency.
In the pre-war era German tank manufacturers relied heavily on a large pool of skilled and willing workers. Even after the outbreak of World War II the armaments industry continued to utilize heavily labour-intensive and costly manufacturing methods unsuited to mass production. Under the influence of Albert Speer the increasing use of forced labour and increased production efficiencies led to a jump in output; although it should be noted that, even with streamlined production methods and slave labour, Germany could not hope to approach the efficiency of Allied manufacturing during World War II
Initial production Panthers had a face-hardened frontal armour which formed the glacis plate the benefits of face-hardening was that it caused uncapped rounds to shatter, but as capped armour-piercing capped rounds became the standard in all armies this expensive and difficult process was no longer relevant and the requirement was deleted on 30th March1943. By August 1943, Panthers were being built only with a homogeneous steel glacis plate which helped to bring down costs and speed up production.
Although the front hull of the panther boasted only 80 mm of armour as opposed to the 100m of the Tiger I, the fact that the armour sloped back at 55 degrees from the vertical, gave it additional advantages and effectively produced the same benefits as the thicker Tiger armour. In addition the front glacis plates were welded and interlocked for additional strength. The combination of a steep slope and thick armour meant that few Allied or Soviet weapons could hope to penetrate the Panther frontally other than at very close ranges.
It was an altogether different matter with regard to the side armour. In order to acheive the weight savings which allowed the Panther to function at all the armour for the side hull and superstructure however was much thinner at just 40–50 mm. The thinner side armour was essential to keep the overall weight within reasonable bounds, but it made the Panther extremely vulnerable to attacks from the side at relatively long ranges 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 millimetre thick skirt armour, known as Schürzen, was fitted to the sides of the Panthers. This flimsy addition was intended to provide protection for the lower side hull from Soviet anti-tank rifle fire and was fixed on the hull side by means of a series of brackets. In the rough conditions encountered in the field these plates were constantly being torn off and many surviving pictures show Panthers missing these side panels.
Panther with track segments hung on the turret sides to augment the armour, 1944.
Zimmerit coating against Soviet magnetic mines was applied at the factory on late Ausf D models commening in September 1943; an order for field units to apply Zimmerit to older versions of the Panther was issued in November 1943. However in September 1944, these orders were countermanded and a new to stop all application of Zimmerit were issued. This new order was based on combat reports that hits on the Zimmerit had caused vehicle fires.
Panther crews were aware of the weak side armour and made unauthorized augmentations by hanging track links or spare road wheels onto the turret and the hull sides. The rear hull top armour was soon recognised as the extreme weak point of the Panther it was only 16 mm thick, and housed two radiator fans and four air intake louvres over the engine compartment. This made the Panther highly vulnerable to strafing attacks by aircraft. With such thin armour even those aircraft armed with just machine guns were potentially dangerous opponents. The Panther was also highly vulnerable to shrapnel damage from airbursts.
As the war progressed, Germany was forced to curtail the use of certain critical alloy materials in the production of armour plate, such as nickel, tungsten, molybdenum, and manganese. The loss of these alloys resulted in substantially reduced impact resistance levels compared to earlier armour. 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 armour 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 armour plate on two out of three Panthers examined.
PANTHER TURRETS AS FORTIFICATIONS
Pantherturm fortification under inspection in Italy in June 1944.
From 1943, Panther turrets were mounted in fixed fortifications, some were normal production models, but most were made specifically for the task, with additional roof armour to withstand artillery. Two types of turret emplacements were used; (Pantherturm III - Betonsockel - concrete base) and (Pantherturm I - Stahluntersatz - steel sub-base). They housed ammunition storage and fighting compartment along with crew quarters. A total of 182 of these were installed in the fortifications of the Atlantic Wall and West Wall, 48 in the Gothic Line and Hitler Line, 36 on the Eastern Front, and 2 for training and experimentation, for a total of 268 installations by March 1945. They proved to be costly to attack, and difficult to destroy.
PANTHER BATALLION ORGANIZATION
From September 1943, one Panzer battalion with 96 Panthers comprised the Panzer regiment of a Panzer-Division 43.
Battalion Command (composed of Communication and Reconnaissance platoons)
Communication Platoon - 3 × Befehlswagen Panther SdKfz.267/268
Reconnaissance Platoon - 5 × Panther
1st Company - 22 × Panther
Company Command - 2 × Panther
1st Platoon - 5 × Panther
2nd Platoon - 5 × Panther
3rd Platoon - 5 × Panther
4th Platoon - 5 × Panther
2nd Company - 22 × Panther (composed as 1st Company)
3rd Company - 22 × Panther (composed as 1st Company)
4th Company - 22 × Panther (composed as 1st Company)
Service Platoon - 2 × Bergepanther SdKfz.179
From 3rd August 1944, the new Panzer-Division 44 organisation called for a Panzer division to consist of one Panzer regiment with two Panzer battalions – one of 96 Panzer IVs and one of 96 Panthers. Actual strengths tended to differ, and in reality were far lower after combat losses were taken into account.
Panzerbefehlswagen Panther Ausf. A (Sd.Kfz. 267) of the Panzergrenadier-Division Großdeutschland photographed in southern Ukraine in 1944.
THE SOVIET RESPONSE
The importance of the tank on the Eastern Front led to an arms race between the Germans and Soviets to produce tanks with ever greater armour and firepower. The Tiger I and Panther tanks were German responses to encountering the T-34 in 1941. Soviet firing tests against a captured Tiger in April 1943 showed that the T-34’s 76 mm gun could not penetrate the front of the Tiger I at all, and the side only at very close range. An existing Soviet 85 mm antiaircraft gun, the 52-K, was found to be very effective against the frontal armour of the Tiger I, and so a derivative of the 52-K 85 mm gun (F-34 tank gun) was developed for the T-34. The Soviets thus had already embarked on the 85 mm gun upgrade path before encountering the Panther tank at the Battle of Kursk.
After much development work, the first T-34-85 tanks entered combat in March 1944. When tested by Wehrmacht, the production version of the T-34’s new 85 mm F-34 gun proved to be ineffective against the Panther’s frontal armour at the standard Panzerwaffe engagement range of 2,000m, meaning the Soviet tanks were out-ranged in open country, while the Panther’s main gun could penetrate the T-34 frontal armour at this range from any angle. Although the T-34-85 tank was not quite the equal of the Panther, it was much better than the 76.2 mm-armed versions and made up for its quality shortcomings by being produced in greater quantities than the Panther. New self-propelled anti-tank vehicles based on the T-34 hull, such as the SU-85 and SU-100, were also developed. A German Army study dated October 5, 1944 showed that from a 30 degree side angle the Panther’s gun could easily penetrate the turret of the T-34-85 from the front at ranges up to 2000 m, and the frontal hull armour at 300 m, whereas from the front, the T-34-85 could only penetrate the non-mantlet part of the Panther turret by closing to a range of 500 m. From the side, the two were nearly equivalent as both tanks could penetrate the other from long range. T-34-85 production was soon varied to allow for the introduction of two replacement guns, the D-5T and ZiS-S-53, the later becoming a production standard for the rest of the war.
The Battle of Kursk convinced the Soviets of the need for even greater firepower. A Soviet analysis of the battle in August 1943 showed that a Corps artillery piece, the A-19 122 mm gun, had performed well against the German tanks in that battle, and so development work on the 122 mm equipped IS-2 began in late 1943. Soviet tests of the IS-2 versus the Panther included a claim of one shot that could penetrate the Panther from the front armour through the back armour. However, German testing showed that the 122 mm gun could not penetrate the glacis plate of the Panther at all, but it could penetrate the front turret/mantlet of the Panther at ranges up to 1500 m. At a 30 degree side angle the Panther’s 75 mm gun could penetrate the front of the IS-2s turret at 800 m and the hull nose at 1000 m. From the side, the Panther was more vulnerable than the IS-2. Thus the two tanks, while nearly identical in weight, had quite different combat strengths and weaknesses. The Panther carried much more ammunition and had a faster firing cycle than the IS-2, which was a lower and more compact design; the IS-2s A-19 122 mm gun used a two piece ammunition which slowed its firing cycle.
THE AMERICAN AND BRITISH RESPONSE
The Western Allies’ response was inconsistent between the Americans and the British. Although the western Allies were aware of the Panther and had access to technical details through the Soviets, the Panther was not employed against the western Allies until early 1944 at Anzio in Italy, where Panthers were employed in small numbers. Until shortly before D-Day, the Panther was thought to be another heavy tank that would not be built in large numbers. However, just before D-Day, Allied intelligence investigated Panther production, and using a statistical analysis of the road wheels on two captured tanks, estimated that Panther production for February 1944 was 270, thus indicating that it would be found in much larger numbers than had previously been anticipated. In the planning for the Battle of Normandy, the US Army expected to face a handful of German heavy tanks alongside large numbers of Panzer IVs, and thus had little time to prepare to face the Panther. Instead, 38% of the German tanks in Normandy were Panthers, whose frontal armour could not be penetrated by the 75 mm guns of the US M4 Sherman.
M4 Shermans in combat.
The British were more astute in their recognition of the increasing armour strength of German tanks, and by the time of the Normandy invasion their program that mounted the excellent 17-pounder anti-tank gun on some of their M4 Shermans had provided more than 300 of these Sherman Fireflies. The British lobbied during the war to use American production lines for building many Fireflies but these demands were ignored due to suspicion of British tank designs after they had done poorly in North Africa. There were also 200 interim Challenger tanks with the 17 pounder and improved tank designs under development. British and Commonwealth tank units in Normandy were initially equipped at the rate of one Firefly in a troop with three Shermans or Cromwells. This ratio increased until, by the end of the war, half of the British Shermans were Fireflies. The Comet with a similar gun to the 17 pdr had also replaced the 75 mm gun Sherman in some British units. The 17-pounder with APCBC shot was more or less equivalent in performance to the Panther’s 75 mm gun, but superior with APDS shot.
British Firefly in Namur, 1944.
The US armour doctrine at the time was dominated by the head of Army Ground Forces, Gen. Lesley McNair, an artilleryman by trade, who believed that tanks should concentrate on infantry support and exploitation roles, and avoid enemy tanks, leaving them to be dealt with by the tank destroyer force, which were a mix of towed anti-tank guns and lightly armoured tanks with open top turrets with 3-inch (M-10 tank destroyer), 76 mm (M18 Hellcat) or later, 90 mm (M36 tank destroyer) guns. This doctrine led to a lack of urgency in the US Army to upgrade the armour and firepower of the M4 Sherman tank, which had previously performed well against the most common German tanks, the Panzer III and Panzer IV, encountered in Africa and Italy. As with the Soviets, the German adoption of thicker armour and the 7.5 cm KwK 40 in their standard tanks prompted the U.S. Army to develop the more powerful 76 mm version of the M4 Sherman tank in April 1944. Development of a heavier tank, the M26 Pershing, was delayed mainly by McNair’s insistence on “battle need” and emphasis on producing only reliable, well-tested weapons, a reflection of America’s 3,000 mile supply line to Europe.
An AGF (Armored Ground Forces) policy statement of November 1943 concluded the following:
“The recommendation of a limited proportion of tanks carrying a 90mm gun is not concurred in for the following reasons: The M4 tank has been hailed widely as the best tank of the battlefield today... There appears to be no fear on the part of our forces of the German Mark VI (Tiger) tank. There can be no basis for the T26 tank other than the conception of a tank-vs-tank duel-which is believed to be unsound and unnecessary. Both British and American battle experience has demonstrated that the antitank gun in suitable numbers is the master of the tank... There has been no indication that the 76mm antitank gun is inadequate against German Mark VI tank.”
U.S. awareness of the inadequacies of their M4 tanks grew only slowly. All U.S. M4 Shermans that landed in Normandy in June 1944 had the 75 mm gun. The 75 mm M4 gun could not penetrate the Panther from the front at all, although it could penetrate various parts of the Panther from the side at ranges from 400 to 2,600 m (440 to 2,800 yd). The 76 mm gun could also not penetrate the front hull armour of the Panther, but could penetrate the Panther turret mantlet at very close range. In August 1944, the HVAP (high velocity armour-piercing) 76 mm round was introduced to improve the performance of the 76 mm M4 Shermans. With a tungsten core, this round could still not penetrate the Panther glacis plate, but could punch through the Panther mantlet at 730 to 910 m, instead of the usual 90 meteres for the normal 76 mm round. However, tungsten production shortages meant that this round was always in short supply, with only a few rounds available per tank, and some M4 Sherman units were not issued with any ammunition of this type.
A Panther tank is passing anti-tank obstacles of the Westwall near Weissenburg/Bergzabern, January 1945.
Sherman tank shells used a high flash powder, making it easier for German crews to spot their opponents. German tanks conversely used a low flash powder making it harder for Allied crews to spot them. Due to the narrowness of their tracks which did little to spread the weight the Sherman also possessed an inferior cross country mobility in relation to the Panthers. This proved to be the case on all adverse surfaces from mud through to sheet ice. Meanwhile it is important to note that the Panther is around 15 tons heavier than the M4. Brig. Gen. J.H. Collier noted:
“I saw where some Mark V tanks crossed a muddy field without sinking the tracks over five inches, where we in the M4 started across the same field the same day and bogged down.”
The 90 mm M36 tank destroyer was finally introduced in September 1944; the 90 mm round also proved to have difficulty penetrating the Panther’s glacis plate, and it was not until an HVAP version of the round was developed that it could effectively penetrate it from combat range. It was very effective against the Panther’s front turret and from the side, however.
The high U.S. tank losses in the Battle of the Bulge against a force composed largely of Panther tanks brought about a clamour for better armour and firepower. At General Eisenhower’s request, only 76 mm gun-armed M4 Shermans were shipped to Europe for the remainder of the war. Small numbers of the M26 Pershing were also rushed into combat in late February 1945. A dramatic newsreel film was recorded by a U.S. Signal Corps cameraman of an M26 successfully stalking and then knocking out a Panther in the city of Cologne, however only after the Panther had already knocked out two M4 Shermans.
Production of Panther tanks and other German tanks dropped off sharply after January 1945, and eight of the Panther regiments still on the Western Front were transferred to the Eastern Front in February 1945. The result was that for the rest of the war during 1945, the greatest threats to the tanks of the Western Allies were no longer German tanks, but infantry anti-tank weapons such as the 88 mm calibre Panzerschreck (the German bazooka) and Panzerfaust anti-tank grenade launcher, and infantry anti-tank guns such as the ubiquitous 7.5 cm Pak 40, and mobile anti-tank guns such as the Marder, StuG III, StuG IV, and Jagdpanzer. A German Army status report dated March 15, 1945 showed 117 Panthers left in the entire Western Front, of which only 49 were operational.
A knocked out Panther tank lies redundant in the river at Houffalize, 1945.
According to US Army Ground Forces statistics, destruction of a single Panther was achieved after destruction of 5 M4 Shermans or some 9 T-34s.
Hitler personally reviewed the final designs for the Panther and it was he who insisted on an increase in the thickness of the frontal armour. Under his orders the front glacis plate was increased from 60 mm to 80 mm and the turret front plate was increased from 80mm to 100 mm.
As a result of Hitler’s intervention the weight of the production model was increased to 45 metric tons an increased by 10 tons from the original plans for a 35 ton tank. To exacerbate matters 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 MAYBACH ENGINE
The first 250 Panthers were powered by a Maybach HL 210 P30 engine, a V-12 petrol engine which delivered 650 horse power at 3,000 rpm and was protected by three simple air filters. Starting in May 1943, the next run of Panthers were built using the 700 PS (690 horse power, 515 kW)/3000 rpm, 23.1 litre Maybach HL 230 P30 V-12 petrol engine. The designs of both engines were excellent and gave a remarkably high output for such a compact device. Two multistage “cyclone” air filters were used to automate some of the dust removal process. Once more however the increasingly difficult supply system encroached and the British control of aluminium supplies from Turkey dictated that the light alloy block used in the HL 210 was soon replaced by a less effective cast iron block. This was done to preserve the limited aluminium supply which was desperately needed elsewhere particularly in the production of jet engines. In practice the engine power output of the engines employed in the Panther was reduced due to the use of low grade petrol. With a full tank of fuel, a Panther could in theory cover 130 km on surfaced roads and 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 comprised of seven discs, each with an outer race of roller bearings, and a connecting crankshaft pin between each disc. To reduce the length of the engine further, by one half a cylinder diameter, the usual practice was abandoned and the two banks of 6 cylinders of the V-12 were not offset. The centre 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 fitted 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 unusual arrangement with the connecting rods was the source of considerable teething problems.
The importance of engine coolants was strongly emphasised in the Pantherfibel.
The cylinder head gaskets were another major problem and the combination of poor fuel and lubricants led to a large instance of blown head gaskets. This was one problem which could be corrected with the introduction of improved seals from September 1943. Another advance lay in the improved bearings which were introduced in November 1943. In common with the Tiger I it was soon discovered that allowing the engine speed to rise to 3000 rpm led to catastrophic failures. The obvious solution was to incorporate an engine governor which was added in November 1943. This essential device reduced the maximum engine speed to 2500 rpm. The situation was further improved by the addition of an eighth crankshaft bearing which was added to the production process beginning in January 1944. This too helped to reduce the previously high rate of motor engine failures.
The importance of keeping the engine revs in a band between 1500 and 2500 is graphically demonstrated in the Pantherfibel.
The weight of the Panther posed major problems for bridge crossings. Like the Tiger I the engine compartment space of the Panther was therefore designed to be watertight so that the Panther could be submerged and cross waterways. The consequence of this was that the engine compartment was poorly ventilated and prone to overheating. In addition the fuel connectors in the early models were non-insulated, leading to leakage of fuel fumes into the engine compartment. This unfortunate combination was the source of many engine fires which blighted the deployment of the early Panthers. The solution was to add additional ventilation venting through the engine deck which was designed to draw off these gasses. To an extent this reduced the instance of engine fires but it did not completely solve the problem and engine fires continued to claim precious Panther tanks. 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. As far as the crews were concerned it was fortunate that the Panther had a solid firewall separating the engine compartment and the fighting compartment in order to keep engine fires from spreading.
The engines fitted into the Panther undoubtedly became more reliable over time, but as events demonstrated there was simply not enough time. In the aftermath of World War II a French assessment of their stock of captured Panthers conducted in 1947 concluded that the engine had an average life of 1,000 km and maximum life of 1,500 km.
The simple gearing for the final drive system of the Panther was easy to manufacture but was far less robust than the relatively complex gearing system on the Tiger.
The suspension system of the Panther closely resembled that of the Tiger I and consisted of two front drive sprockets, two rear idlers and eight double-interleaved rubber-rimmed steel road wheels on each side. The road wheels were suspended on a dual torsion bar suspension. The dual torsion bar system was designed by Professor Ernst Lehr and was purpose designed to allow for a wide travel stroke and rapid oscillations with high reliability. The result of the innovative dual torsion bar system was meant that it was possible for the Panther to attain a relatively high cross country speed and the impressive ability to travel at high speed cross country was a defining feature of this remarkable heavy tank. The high speed of the Panther could be maintained over undulating terrain. However, the speed of the Panther came at a very high price. The extra space required for the bars running across the length of the bottom of the hull, below the turret basket significantly increased the overall height of the tank and also prevented the incorporation of an escape hatch in the hull bottom. When damaged by mines, the finely engineered torsion bars were easily bent out of shape required a welding torch for removal.
The importance of maintain the running gear in good condition from the Pantherfibel.
The Panther’s suspension was complicated to manufacture and in common with the Tiger I incorporated the interleaved system which required the outer wheels to be removed in order to access the rear wheels and made replacing inner road wheels time consuming. The crews of the Panther would no doubt have been relieved to discover that the road wheels on their vehicle were arranged in just two rows as opposed to the three of the Tiger I.
Taken in Northen France in October 1943, this photograph clearly shows the interleaved wheels of the Panther.
One tiresome feature of the interleaved wheels was that they exhibited a tendency to become clogged with mud, snow and ice, and could easily 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 armour protection for the thin hull sides than smaller wheels or non-interleaved wheel systems, but the complexity and the tedious processes involved in maintenance meant that no other country ever adopted this cumbersome design for their tanks.
The road wheels of the Panther were rubber rimmed but in September 1944, and again in March/April 1945, M.A.N. the shortages of this vital substance led to the building of a limited number of Panther tanks with steel road wheels which were originally designed for the Tiger II and late series Tiger I tanks. Steel road wheels were introduced from chassis number 121052.
Once the Allied air forces began targeting Schweinfurt the resultant shortage of ball bearings was another major issue and in consequence, from November 1944 through February 1945, an emergency conversion process began which revolved around the use of sleeve bearings as an alternative to ball bearings. The sleeve bearings were primarily used in the running gear although contingency plans were made should the need arise to convert the transmission to sleeve bearings, but these were not carried out as production of Panther tanks came to an end.
STEERING AND TRANSMISSION
Repair of the transmission of a Panther, Russia, May 1944.
In the Panther, steering was accomplished through a seven-speed AK 7-200 synchromesh gearbox. It was designed by Zahnradfabrik Friedrichshafen, and incorporated a MAN single radius steering system which, unlike the Tiger I with its steering wheel operation, the Panther utilised the traditional arrangement of steering levers.
On the Panther 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 anticipate the sharpness of a turn and shift into the appropriate gear to turn the tank. The driver also had the option of engaging 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 I and ease of manufacturing compared to the Tiger I was therefore much enhanced. The AK 7-200 transmission was also capable of pivot turns, but this method of turning placed a great deal of additional strain which could accelerate failures of the final drive.
The seven forward and one reverse gear of the Panther from the Pantherfibel.
Throughout its career, the weakest part of the Panther was its final drive unit. The problems arose 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 more simple 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 such a high stress gearing arrangement. 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 poor type of steel available and 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.
The turning radius of each of the Panther’s forward gears from the Pantherfibel.
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 the Panther had to be driven by experienced drivers with extreme care, a characteristic shared with the Tiger tanks as well as Jagdtigers. Long road marches would inevitably 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. This theoreticaly convenient and sensible arrangement was not always achievable in practice and the Panthers continued to face unfeasibly long road marches which led to numerous breakdowns.
THE PANTHER II
The early impetus for upgrading the Panther came from the concern of Hitler and others that it lacked sufficient armour. Hitler had already insisted on an increase in its armour once so far and further discussions involving Hitler, in January 1943, resulted in a call for further increased armour; initially referred to by an Arabic numeral as the Panther 2, it was redesignated with the Roman numeral becoming the Panther II after April 1943. This upgrade increased the glacis plate to 100 mm, the side armour to 60 mm , and the top armour to 30 mm. Production of the Panther 2 was slated to begin in September 1943.
In a meeting on February 10, 1943, further design changes were proposed - including changes to the steering gears and final drives. Another meeting on February 17, 1943 focused on sharing and standardizing parts between the Tiger II tank and the Panther 2, such as the transmission, all-steel roadwheels, and running gear. Additional meetings in February began to outline the various components, including use of the 88 mm L/71 KwK 43 gun. In March 1943, MAN indicated that the first prototype would be completed by August 1943. A number of engines were under consideration, among them the new Maybach HL 234 fuel-injected engine (900 hp operated by an 8-speed hydraulic transmission).
It was a sign of the rapid pace of events that the up-grade path to replace the original Panther design with the Panther II were already underway even before the first Panther had even seen combat. However from May to June 1943, work on the Panther II ceased as the focus shifted to expanding production of the original Panther tank. It is not clear if there was ever an official cancellation - this may have been because the Panther II upgrade pathway was originally started at Hitler’s insistence. The direction that the design was headed would not have been consistent with Germany’s need for a mass-produced tank, which was the goal of the Reich Ministry of Armament and War Production.
One Panther II chassis was completed and eventually captured by the U.S.; it is now on display at the Patton Museum in Fort Knox. An Ausf G turret is mounted on this chassis.
PANTHER AUSF. F
After the Panther II project was abandoned, a more limited upgrade of the Panther was planned, centered around a re-designed turret. The Ausf F variant was slated for production in April 1945, but the war ended these plans.
The earliest known redesign of the turret was dated November 7, 1943 and featured a narrow gun mantlet behind a 120 mm (4.7 in) thick turret front plate. Another design drawing by Rheinmettall dated March 1, 1944 reduced the width of the turret front even further; this was the Turm-Panther (Schmale Blende) (Panther with narrow gun mantlet). Several experimental Schmalturm (literally: “narrow turret”) were built in 1944 with modified versions of the 75 mm KwK 42 L/70, which were given the designation of KwK 44/1. A few were captured and shipped back to the U.S. and Britain. One is on display at the Bovington tank Museum.
The Schmalturm had a much narrower front face of 120 mm (4.7 in) armour sloped at 20 degrees; side turret armour was increased to 60 mm (2.4 in) from 45 mm (1.8 in); roof turret armour increased to 40 mm (1.6 in) from 16 mm (0.63 in); and a bell shaped gun mantlet similar to that of the Tiger II was used. This increased armour protection also had a slight weight saving due to the overall smaller size of the turret.
The Panther Ausf F would have had the Schmalturm, with its better ballistic protection, and an extended front hull roof which was slightly thicker. The Ausf F’s Schmalturm was to have a built-in stereoscopic rangefinder and lower weight than the original turrets. A number of Ausf F hulls were built at Daimler-Benz and Ruhrstahl-Hattingen steelworks; however there is no evidence that any completed Ausf F saw service before the end of the war.
Proposals to equip the Schmalturm with the 88mm KwK 43 L/71 were made from January through March 1945. These would have likely equipped future German tanks but none were built, as the war ended.