Drawing by H. L. Doyle from Panther and Its Variants
Drawing by H. L. Doyle from Panther and Its Variants
The following article comes courtesy of Bruce Crosby
THE PANTHER THAT WASN'T
THE NEED FOR RATIONALISATION
The Heereswaffenamt (Army Weapons Department) of
the German Army became increasingly aware of the need to
conserve materials and manpower as the war progressed. A
development (Entwicklung, or E) program was started to
investigate certain aspects of tank design, but using the
design offices of engineering companies which had no previous
experience of tanks.
The basic ideas were to save internal space, save
time and effort, standardize parts and carry out research into
gun stabilization. Why maximize internal space? A larger gun
needs larger ammunition and related systems, and there was no
room for further expansion in the current range of vehicles.
Gun stabilization would give a degree of fire on the move
capability and also alleviate trunnion loads as the tank
travelled cross country. The designs were to not use torsion
bars as these took up an inordinate amount of room, but have
bolt on external suspension units, and preferably have the
gearbox and final drive at the rear of the hull. These latter
items were to be simplified where possible to minimize
machining and gear cutting operations. This layout would have
been somewhat of a compromise as tests by the Germans had shown
that tractive effort was far greater with front drive, but the
components were less vulnerable to anti-tank fire mounted at
the rear and also gave greater internal space in the fighting
compartment (this is directly opposite to the latest Israeli
thinking which puts crew safety as the prime consideration,
hence the Merkava has the engine and transmission at the front
to act as armour). If possible plain bearings were to be used
in place of ball and roller bearings.
Despite round the clock bombing by the Allies,
production of tanks was actually at a very high level.
However, the armed forces were scraping the barrel for
manpower. Redundant Kriegsmarine sailors were being used
as line infantry and the simplified production requirements
of the E-series would have freed up a lot more men from the
factories. It must be remembered that for ideological reasons
the Germans did not use women in their factories except for
some secretarial tasks, unlike their opponents Britain, America
and the USSR who used female labour in tank, aircraft and
munitions factories, releasing men to fight. In the Nazi
scheme of things women were to be dedicated to Kirche, Kuche,
Kinder, which means "church, kitchen and children". Instead
Germany used inducted foreign labour from the occupied
countries and slave labour from P.O.W. and concentration
camps. None of these groups were exactly pleased to be working
for their captors and the quality of the work suffered as a
Direction of the program was by Waffenprufamt 6
(WaPruAmt 6) under General H.E. Kniepkamp, a capable and
prolific engineer and good administrator. A direct translation
of this organisation is "Weapon test establishment, section
6". By the end of the war Kniepkamp had patented about 50
individual designs concerning track laying vehicles. The firms
involved in the E series were Klockner-Humbolt- Deutz of Ulm,
makers of the Diesel powered RSO/03, Argus of Karlsruhe, Adler
of Frankfurt, and Weserhuette of Bad Oeyenhausen. They were
all mainly component manufacturers, making things like engines,
gearboxes and brakes for the larger concerns such as MAN and
Daimler-Benz. They were to design respectively tanks in the
10, 25, 50, and 75 ton weight brackets. Adler were also
directed to design a super heavy tank in the 100 ton class,
which was actually built. The E-100 was to have had a turret
practically the same as the Maus and was brought back to
England at the end of the war, partially assembled, only to be
scrapped later. (Military Modelling featured the E-100 in the
June 1991 issue, written by Jonathan Roberts)
Adler was primarily a car builder but also
supplied parts for half tracks, and designed the "A" and HK300
series of one tonne half tracks to be developed in parallel to
the Demag series. These remained prototypes, no series
production was undertaken. Later Adler was involved in the
proposed replacement for the one tonne half tracked tractors,
the leWS (leichte Wehrmacht Schlepper or light army tractor),
which was usurped by the R.S.O. fully tracked tractor.
THE NEED FOR A NEW PANTHER
Construction of the existing Panther was a major
problem. Although a fine tank it took an extraordinary amount
of manpower, time and resources to build, even to the detriment
of the fighter aircraft program which was priority one. In
retrospect, at the design competition stage the Germans had
picked the wrong vehicle. The Army wanted a direct copy of
the Soviet T-34 but this was not possible as it used materials
that were rare in Germany, such as an aluminium alloy engine.
It was also politically impossible because Hitler and the
leaders of the Reich would not contemplate a copy of a Soviet
design for ideological reasons.
The firms of Daimler-Benz of Stuttgart and MAN
(Maschinenfabrik Augsburg- Nurnburg) were chosen to design
tanks which were then tested against each other. The
Daimler-Benz offering had a fuel saving diesel engine, rear
gearbox, simple external leaf spring suspension and practically
the same armour disposition as the vehicle it was meant to
defeat, the T-34. It would have been cheap and easy to
manufacture and relatively simple to up gun, even though it
had quite a small turret. The MAN designed tank that reached
production was big, fuel guzzling and so complicated it was
unreliable. The turret was a redesign of an earlier attempt
at a 7.5 cm armed turret by Rheinmetal-Borsig for the Henschel
Tiger. There were plenty of teething troubles, mainly due to
Panther being underpowered and far too heavy: in service the
gearboxes were not strong enough to take the engine power, the
engines themselves over heated causing fires and the wheels
were too weak, resulting in the rims breaking under load.
Although they lost the original design contract, Daimler-Benz were eventually brought into the Panther production group and became heavily involved in later development of the series. Panther was refined on later models but still gave lots of problems right up to the end of the war. By then it was undergunned as well when compared to its Soviet counterpart the IS-2, taking into account size and weight. (I suppose the mail box will be full of letters to the Editor with the usual stuff about "Panther was finest medium tank , etc, etc", but I stand by my statement) Compared to contemporary Soviet and American designs the Panther was just too large and far too complicated for the gun it
There is always a lot of confusion about Panther wheel types so perhaps a quick run down on them would be in order here. Late Panther Ausf G would have been identical to the standard G except for 860 mm steel tyred (Gummisparende or "rubber saving") wheels. Ausf F would have had the G hull and 860mm steel wheels, with the Schmalturm armed with the 7.5 cm gun. Early and late 860mm Panther wheels were interchangeable on the vehicle and in fact the steel ones were meant to be a direct replacement as the rubber tyred ones wore
German industry tried to make an improved and simplified version in the Panther II, fitted with the Schmalturm armed with the 8.8 cm gun, but the revised chassis was still too complicated for the Heereswaffenamt, even though the number of torsion bars in the chassis had been halved by using the single bar layout of the Tiger II. It was to have 800mm steel wheels and would have used many components from the Tiger II such as gearbox and final drive as well. The Panther at Aberdeen Proving Ground in Maryland is the prototype chassis for the Panther II but it is fitted with a standard G turret armed with the 7.5 cm
Note the difference in wheel size between the late Panther Ausf G/Panther Ausf F and the Panther II/Tiger pattern: they look just about the same but were 60 mm different in diameter, made from different parts, bearings, etc, and thus were not interchangeable between Panther and Tiger.
Schmalturm had been developed as a joint effort by Daimler-Benz and Skoda for the late Panther F and Panther II, to be armed with the new KwK 44/7.5 cm gun developed by Krupp and Skoda. Panther F and Panther II would probably never have reached production because of the work on the E series, but it was decided to keep the Schmalturm as, during tests, it was found to have excellent armour protection, could be fitted with either the 7.5 cm or 8.8 cm gun and was cheaper, taking 30% less time to manufacture than the original turret. Frontal armour was raised from 80 to 120 mm with corresponding increases in the sides and roof armour as well. Note that the turret roof was flat, whereas Panther, Tiger I and Tiger II all had sloping front roof sections to allow the commander to have better forward vision. It had a good stereoscopic range finder made by Zeiss and incorporated a gyrostabilizer, copied from (or at least based on) the stabilizer mounted on the American Lee/Grant and Sherman tanks.
There were even plans to mount Schmalturm on the hull of the Panzer IV, using the 7.5 cm KwK 44 L/70 gun (Spielberger vol 5: Der PzKfw IV und sein Abarten, pp 78/79). For the E-50/E-75 series the 7.5 cm was dropped and replaced with a development of the 8.8 cm KwK 43 L/71, the 8.8 cm KwK 44 L/71. The breech was redesigned to take new ammunition which used a shorter, fatter cartridge to ease handling in the reduced space. Ammunition stowage was all in the hull, unlike the Tiger II where some was stored in the large turret bustle. The gun was mounted forward so the breech did not protrude into the turret too much.
There are references to a semi-automatic loading system designed and built by Skoda and trialed in Schmalturm. The 7.5 cm KwK 44/2 gun may have been fitted with a recoil operated automatic loader/rammer operating with a four round cassette, which the crew just had to top up. It was expected to produce a firing rate of 40 rounds per minute, but it is doubtful if the poor loader would be able to keep up! There was probably not enough room in the 8.8 cm armed turret for this apparatus.
A large circular hatch was fitted at the rear of the turret for crew access and ammunition supply. Adjacent to it was a port for firing weapons, probably the MP43/StG44 Sturmgewehr which was possibly fitted with the Krummerlauf attachment, a bent barrel which allowed the gun to fire around corners. Another anti-personnel weapon fitted as standard was the Nahverteidigungswaffe (close defense weapon), mounted in the turret roof on the right hand side. This was basically a breach loaded gun similar to a signal pistol. It threw a small grenade about ten feet into the air where it exploded, scattering lethal ball bearings and shrapnel. It was very effective at clearing the decks of enemy infantry.
The commanders' cupola was fitted on the left hand side of the turret roof and was a low profile design quite similar to the one on the King Tiger, except that the hatch was set to hinge up and out, rather than be pushed up on a pillar and swung sideways. The production vehicle cupola would probably have been fitted with a skate rail for an anti-aircraft machine gun as well.
By modern standards the turret is very small, but it still housed the best gun of the era. Head on it was very narrow and would have made a difficult target to hit. Schmal does not actually mean small in English but narrow or thin, refering to the small front compared to the original Panther. Coupled with the new Saukopf (pig's head shaped) mantlet, this eliminated the shot trap formed by the original Panther turret's wide curved mantlet and the top of the driver's compartment. An example of the turret was brought back to England post war only to have pieces cut out of the sides and then end up as a hard target on the ranges. At the time of writing it can be seen in its current shape on the grass in the corner of the car park at the Tank Museum, but it is of little use to the modeller as there isn't much of it left.
It was decided that torsion bars were difficult and costly to make, and as the larger factories were getting bombed round the clock something was needed that could be simple enough to hand to small engineering concerns to fabricate under sub- contract. The new bogie carried 800mm steel rimmed "rubber saving" wheels from the Tiger II. This type of wheel is often refered to as "silent bloc". (A similar design was also seen on the late Jagdpanzer IV chassis, albeit a much smaller size. Also Spielberger vol 9: Der PzKfw Panther und sein Abarten pp 71 has a photo of a new Panther G at a showing for the top brass. In the background is a Hummel munitions carrier with six medium size silent bloc wheels, designed by Krupp. To the best of my knowledge this design did not enter service, nor have I seen any other photos of it) The wheels were mounted on geared swing arms suspended against springs made of simple Belleville washers held in tubes, with a hydraulic shock absorber down the centre of each. The suspension unit was designed by MAN of Augsburg, and was small, due to the high loading it could take, and easy to produce. The washers could be churned out on most stamping machines. The axles for the swing arms still needed machining on a lathe, but they were nowhere near the size of torsion bars. The complete bogie was refered to as "Einheitslaufwerk", or standardized running gear. A lesson learned from the American Sherman suspension was that none of the components was handed. The wheels straddled the track guide teeth, but the same length axles were used: the wheels had a bearing spacer on one side which could be reversed, setting one wheel in and one wheel out. An escape hatch could be fitted in the hull floor now, almost impossible with torsion bars. Mine damage would be much easier to fix as the complete unit could be unbolted and replaced, where as mine damaged and buckled torsion bars often had to be removed with a cutting torch, after the interleaved wheels had been removed first of course.
The standard Panther had eight axles per side, requiring eight precise holes in each side of the hull. These had to be cut and machined with the hull in a huge special rig. Add sixteen chrome steel torsion bars (in reality 32 as each bar crossed the hull then was geared to cross back over the hull again), complete with machined bearings, specialist heat treatment, etc. Compare that with six small housings filled with plain steel washers and a couple of shock absorbers, fixed by bolts. I don't have a cost breakdown but a similar exercise was carried out by Porsche on the Jagdtiger and the savings were 50% in material costs and tooling, a 40% weight reduction and 60% on labour time (again, the Porsche suspended Jagdtiger can be seen at Bovington). Another way of saving money was to have only one wheel on each axle - the normal interleaving was two per axle - two axles per bogie and three bogies per side. This arrangement gave the E-50 twelve road wheels as opposed to 32 on the original Panther, alone a massive saving of time and effort.
The E-50 hull was to be longer than the Panther, in fact it was practically identical to the King Tiger in overall dimensions except for the glacis plate layout. This large hull combined with the Schmalturm gives the completed vehicle a somewhat pin headed appearance. As mentioned above the amount of drilling and machining was reduced drastically. The plates would have been interlocked and welded as on other German vehicles, giving great strength and rigidity. Like the Panther and King Tiger hulls, lifting and shackle points were all cut into the flat plates rather than bolt on items like the earlier Panzer IV.
The hull of the replacement for the King Tiger, the E-75, was going to be almost identical to the E-50, except the armour would have been thicker. Two extra bogies, one each side, would have been fitted to compensate for the extra weight. The bogies were re-spaced as well giving the E-75 a track to ground contact length of 4095mm, compared to 3850mm for the E-50. The whole drive train would have been the same for E-50 and E-75. As they were both to be armed with the same gun, ammunition stowage and overall internal layout was to be identical.
German scientists and engineers were working on infra-red lighting and sights for the Panther as the war drew to a close. An assembly of infra-red sight and 200 Watt lamp could be fitted into the commanders cupola opening to be used by the vehicle commander with his head out. This could certainly have been fitted to E-50 with minor modification only. It was to be used in conjunction with UHU and FALKE. UHU was a large 60 cm 6 kW infrared searchlight mounted in a Sd.Kfz. 251 half track (conversions are now available from Verlinden and MB Models). FALKE was a standard Sd.Kfz. 251 APC with infra-red drivers' scope and lamp and a roof mounted MG 42 with infra-red scope and lamp (see Sturm und Drang 3 for good photos). The individual infantrymen were to be armed with the MP43/StG44 Sturmgewehr which was fitted with a smaller infra-red sight; the batteries and electronics were carried in a large back pack. Nowadays all fighting vehicles have some form of night fighting equipment, but it must be remembered that it is all derived from these early attempts by the Germans.
The engine chosen was an improved version of the Maybach HL230 as fitted to the Panther and the Tiger II. Called the HL234, it developed 900 HP using fuel injection, and was expected to produce up to 1200 HP with supercharging. The improvements included sodium filled valves to withstand the higher exhaust gas temperatures. The location of fuel tanks, radiators and fans was similar to the Tiger II. Maximum speed was to be 60 KPH for the E-50 and 40 KPH for the E-75. The idea was to assemble both types on the same production line, using identical production machinery and brought in sub assemblies.
As mentioned earlier the final drive for the whole series was meant to be at the rear of the vehicle. However none of the drawings of E-50/75 make any space allowance at all for a rear gearbox and final drive except for adding teeth to what was the idler. For instance the turret would probably have to be a couple of feet further forward on the hull top. Also they all show the standard Tiger II sprocket at the front of the vehicle as well! I think that the E-50 probably had the gearbox at the front: the E- 100 certainly did. I believe the projected rear drive motor was to have been the Maybach HL233P with ZF gearbox but my German isn't that good!
E-50 and E-75 were to have been the backbone of the German army, with most other fighting vehicles such as self propelled guns, etc, on either Waffentrager or Panzer 38D chassis. The E-25 was quietly dropped in favour of the 38D, a wholly German, greatly simplified and enlarged development of the Czech Panzer 38(t). Panzer IV chassis production was to be phased out completely as all the weapons it carried in its various guises could be taken by the 38D which was two thirds the weight and size. With that sort of rationalisation of the ground forces in equipment, logistics and training combined with new automatic personal weaponry such as the MP43/Sturmgewehr 44 and the traditional tenacity of the German soldier, the Wehrmacht would have been an even harder enemy if the war had gone on into 1946/47. The Army would have been complemented by an all jet Luftwaffe and strategic forces using long range ballistic missiles, such as developed versions of the V-2!
As a point of interest a vehicle with all the requirements of the German Army was about to appear as the war came to a close: external suspension, rear gearbox, big gun, heavy armour, lots of room for expansion, etc. It wasn't German however, but the British A41 "Centurion", which is another story altogether.
The engineering behind the E-50 did not die with the end of the Third Reich. Development of some of the features of the E series was carried on elsewhere. The idea of external Belleville washer suspension resurfaced on the Swiss Panzer 61, where it was put to good use as the tank was quite small and needed all the interior space it could get. Kniepkamp, now head of his own design bureau, made a significant contribution to this programme, and later to the Standardpanzer Leopard as well.
The French designed and built the AMX-50 series which used a lot of the Panther/E- 50 ideas. It still used torsion bar suspension and overlapping roadwheels like the King Tiger, swivel hatches like the Panther A and a 1000HP Maybach engine with rear drive, just like the E-50 was meant to have! The engine deck layout was practically identical to the Panther/Tiger II type, but the rear hull was longer and re- shaped to allow for the gearbox and final drive. From the photos I have seen the drive sprocket was from the Panther, or very similar, as was the track. This was not too surprising as the French Army used a couple of regiments of captured Panthers well into the late forties. The AMX 50 turret was an oscillating design like a rather large AMX 13 turret, mounting either a 100 or 120 mm cannon. Later developments look like they had Tiger II track, needed to reduce ground pressure as the armament and armour size and weight rose. The AMX-50 was not developed past the prototype stage as the new generation of Main Battle Tanks was appearing, France's being the smaller and lighter AMX-30. If anyone has more info on the AMX-50 series, especially photos and drawings, I would be very pleased to hear from them.
© Bruce Crosby All rights reserved, though all feedback/comments welcome
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