King Tiger in the SMM Full-Reuenthal
Development of King Tiger
The King Tiger as the successor of the Tiger I was the culmination of the german heavy tank development in world war II. The Jagdtiger surpassed him in terms of weight by some tons but was not the better tank in an entire view of movability (weight and motor power), fire power and armor.
The roots of the heavy tank Tiger II date back in 1937 when first concepts were developed for a tank in the range of 30 tos. The initial concepts later split into Panther and Tiger development.
Aspects for the choice of suitable tank engines:
The availability of suitable engines is an important precondition for the development of heavy tanks. A common high performance engine back in 1937 was the Maybach HL 120 TRM of the Panzer IV, a V 12 which generated 280 HP from 12 l cc. A vehicle weight resulted in a power to weight ratio of 10 hp/l, which was generally considered as being insufficient. Targeted was a ratio of ca. 20 hp/l which required a 600, preferably 700 hp engine for a 30 to. tank.
Some engine manufacturers expressed doubts as to whether such an engine could be realized with 12 cylinders, a 16 cylinder construction might be needed instead. Since back in these times the power of an engine went more or less in line with its dimensions, the space to house a 16 cylinder engine would have considerably narrowed the fighting compartment of a tank.
Plane engines were considered as alternatives. Such motors provide their maximum torque at low revs which in turn meant the requirement of appropriate dimensioning of drivetrain components such as reduction gears. This would have added to the total weight and gone at the expense of maneuverability. The plan for plane engines was dropped.
No hints were found as to why the germans generally opted for gasoline engines. The reason was probably the better ration of power to space demand compared to diesel engines
Development stages to the King Tiger:
The Heereswaffenamt resp. the sub-organisation Waffenprüfamt 6 (Waprü 6) / Panzer und Motorisierung, Tanks and Motoring usually splitted development orders and awarded partial contracts to multiple companies. Orders for the manufacturing of the armor hulls, the turret hulls and the guns usually were awarded to Krupp. Wegmann did the assembly of the turrets from its components while Henschel performed the fine processing of e.g. raw armor hulls and the final assembly of the tanks with all components of subcontractors.
In 1937 the companies Henschel, Daimler-Benz and MAN were awarded contracts for the development of a 30 to. Tank. Ferdinand Porsche AG entered the game at a later stage.
The concepts of Daimler Benz / MAN later lead to the mid-weight Panther types while the Henschel concepts resulted in the heavy-weight Tiger tanks.
D.W. / Durchbruchwagen Breach car
Following an order of Waprü 6 of january 1937 for the development of a 30 to. chassis, Henschel designed an armor hull of soft steel with a wall thickness of 50 mm all around and 20 mm for hull bottom and roof. The sidewalls were a bolted two-piece unit because at that time rolling of a single armor wall was not yet possible.
Separate driving and steering gears were used. Track width was 20 cm and a Maybach HL 120 engine with 280 HP was installed. The name referred to the new role in combat envisioned for the vehicles.
Already in April 1937 Henschel presented an improved concept, DW 2. This was very similar to DW 1 but featured some motoring improvements.
Source: T. Jentz, H. Doyle: Germany’s Tiger tanks: D.W. to Tiger I
Already in november 1936 Krupp was awarded a contract for the construction of a turret for a 30 to. vehicle. A 7,5 cm gun was planned to be mounted. Since Krupp delivered only a design concept test runs with the chassis were conducted with concrete plates on the hull to simulate the turret weight.
VK 30.01 (H) und (P)
The development of the VK 3001 (H) at Henschel was based on the experiences from the D.W.-project. In line with the order specifications Henschel constructed a chassis with 50 mm armor around, 25 mm top and 20 mm hull bottom thickness. The hull side walls were made in one piece. Its suspension featured torsion bars with interleaved 70 cm-roadwheels, return rollers and a track width of 52 cm. The installed Maybach HL 116 with 6 cylinders and appr. 300 hp provided a maximum speed of ca. 35 km/h.
Some months earlier Krupp was awarded a contract for the design of a turret with the 7,5 cm KwK L/24 and two machine guns, one pointing to the front and one to the rear.
Source: T. Jentz, H. Doyle: Germany’s Tiger tanks: D.W. to Tiger I
Three chassis were produced between march and may 1940, two of which were later converted to self-propelled guns ‚Sturer Emil‘ (stubborn Emil) with an 12,8 cm gun. One chassis remained as a test vehicle. Later four more chassis were built for tank driver education.The chassis were never completed with the 7,5 cm KwK L/24 turrets designed for them. The turrets were later used as fixed turret emplacements at the Atlantikwall.
Towards the end of 1939 also Porsche entered the game of constructing a 30 to. tank chassis with its type 100 which was built in the new Nibelungenwerke in Austria near Linz.
While the drivetrain concept of Henschel was conservative with a gasoline engine and a mechanical transmission, Porsche acted independently and designed a gasoline-electrical drivetrain with two parallel mounted air-cooled engines with 10 l displacement, 10 cylinders and 210 hp, each directly driving the central axle of a generator for the sprockets.
VK 3001 (P) / Porsche-Typ 100 Source: T. Jentz, H. Doyle: Germany’s Tiger tanks: D.W. to Tiger I
On the drivetrain Porsche realized another Porsche-own feature: the wheel car with two wheels offset to each other, and a torsion bar linked by 90°, so being arranged in driving direction. As with the gasoline-electric drivetrain this concept was maintained for all Porsche designs for Tiger tanks during the war.
The air-cooled engines of this vehicle named ‚Leopard’ proved to be very sensitive and required excessive maintenance. The drivetrain concept was innovative but too unreliable and complicated for the desired utilization. Only one chassis was built.
VK 3601 (H)
By mid 1940 Henschel was awarded a contract for the construction of a chassis which was based on the VK 3001 (H) but should be equipped with a turret with a 105 mm gun. In addition it was to have a front armor of 100 mm. The wider turret ring and the consecutively necessary modifications of the armor hull increased the total weight.
The design featured a hull armor of 80 mm in front, 50 mm on the sides and rear and 25 mm on bottom and hull top. The Maybach HL 174, a 12 cylinder engine with 450 hp, the 8-gear-OLVAR 40 12 16-transmission and the Henschel L 600C steering gear was installed. The diameter of the metal roadwheel discs was 800 mm and the maximum speed was 50 km/h.
VK 3601 Source: T. Jentz, H. Doyle: Germany’s Tiger tanks: From VK 4501 to Tiger II
When Waprü 6 stopped the plan of installing a 10,5 cm gun, the tapered bore gun 0725 was considered as an option. However, since the amount of tungsten necessary for the ammunition of this gun was not available in Germany, also this concept was skipped.
Finally the VK 3601 (H) was planned to be equipped with the same turret with the 8,8 cm KwK L/56 which Krupp developed in cooperation with Porsche for the chassis VK 4501 (P).
Besides the prototype four more chassis were built which were later used as towing vehicles.
VK 4501 (H) and (P)
Krupp received the order for the developent of a turret for the VK 3001 series and contacted Porsche with the proposal to use the 8,8 cm KwK L/56. The necessary modifications, e.g. to enhance the Kranzdurchmesser to 1850 mm, increased the weight to over 40 to. The project VK 4501 (P) resulted from the decision to increase front armor to 100 mm.
Furthermore both 10 l-engines were replaced by 15 l cc and 310 hp each, which drive two Siemens generators of 275 KW each. On the suspension Porsche switched from rubber-lined wheels to rubber-saving wheels with a rubber-cushion between the two discs of a wheel.
VK 4501 (P) Quelle: T. Jentz, H. Doyle: Germany’s Tiger tanks: D.W. to Tiger I
Several vehicles were built but only one was put in service.
Ultimately, HWA pursued only two concepts for the project which meanwhile was officially called ‘Tiger project’: The VK 3601 from Henschel and the Porsche type VK 4501 (P). An order for the production of six chassis each within a year went to both companies. After all considered gun options for the VK 3601 turret were dropped, the 8,8 cm turret designed for the Porsche chassis was to be used on the Henschel chassis as well. The necessary modifications to fit the turret resulted in a
VK 3601 Source: T. Jentz, H. Doyle: Germany’s Tiger tanks: D.W. to Tiger I
concept above 40 to., the VK 4501 (H). The most striking feature of the modified Henschel chassis were the side walls which now reached to the outer track rims and were appr. 30 cm further to the center on the VK 3601.
Already at this stage the development was called ‘Projekt Tiger’.
During the campaign against Russia german troops encountered the Russian types T 34 and KW 1 and 2 which proved superior to the german tanks in many respects. This particularly boosted the development of heavier german tanks. Testimony to the urgency is the fact that developments were put in service more or less without considerable testing.
In this sense Krupp received an order for the production of 100 armor hulls VK 4501 (P) even though the final decision for that concept has not yet been made.
Both manufacturers, Henschel and Porsche, were ordered to finish a demonstration vehicle until april 20th, 1942. Both were able to comply on the last moment, without having tested the vehicles.
During the test runs the Porsche car could not prove its suitability for a large series production and ultimately the Henschel design was accepted.
Panzerkampfwagen Tiger, Ausführung E / Tiger I
The official order for serial production of the Tiger I was awarded to Henschel in october 1942, production already started in august 1942. A total of 1350 tanks were built until august 1944.
The Tiger I was built in only one version even though multiple modifications were realised during the production. This was the case particularly in the beginning when the vehicles which were produced literally from the drawing board suffered from many teething problems.
The most visible modification was the switch from rubber-lined wheels to rubber saving wheels starting in February 1944.
Tiger I, Fgst-Nr. 250570, October 1943 Source: T. Jentz, H. Doyle: Germany’s Tiger tanks: D.W. to Tiger I
VK 4502 (H), VK 4502 (P) Porsche-Typ 180, / VK 4503 (H)
Even though the worst problems of the Tiger I were solved after a while and it basically stood the test, order was given to soon replace it by an improved version.
A central goal was the installation of a gun with an improved penetration power. Apart from this a standardization to the largest extend possible of assembly parts with the to-come Panther II which was developed simultaneously was targeted. Furthermore the new Tiger was to get sloped armor for better protection.
Though being rejected twice Porsche stuck to his innovative concepts and kept optimizing them. His VK 4502 (P) / Porsche-type 180 emerged as an improved version of VK 4501 (P) immediately after he failed to get the award of contract for the Tiger I. It came with the same suspension and drivetrain features, … and the same drivetrain problems.
Porsche didn’t introduce a single vehicle but a concept with combination options for turret position (front and rear), drivetrain (hydraulic and electrical transmission) and four different engine types. Nonetheless, engine unreliabilities again led to a rejection of his concept.
Porsche-Typ 180 mit Turm hinten
In april 1942 Henschel started work on a chassis for a turret with the long gun 8,8 cm KwK L/71. Construction of a transitional project vehicle VK 4502 (H), as proposed by Henschel due to the huge changes to standardize the Tiger with the Panther II, was turned down by Waprü 6, and the concept VK 4503 (H) became the basis for the later King Tiger.
Its first version resembled VK 4501 (H) to a large extend. Later the design was modified to resemble the Panther with its sloped side and front armour plates. Krupp designed one turret for both concepts, the difference being an electric traverse drive for the Porsche and a hydraulic drive for the Henschel vehicle.
From October 1942 to march 1945 a total of ca. 492 Tiger II were built (sources are inconsistent on the total number). After the first 50 turrets, often referred to as ‘Porsche turrets’, production switched to the regular production turrets or ‘Henschel turrets’ from june 1944.
Königstiger mit Serienturm Source: T. Jentz, H. Doyle: Germany’s Tiger tanks: From VK 4501 to Tiger II