The VK4501 (Tiger P)
|Place of origin||Nazi Germany|
|Number built||1 Served as Command Tank|
|Weight||59 tonnes (65 short tons; 58 long tons)|
|Length||9.34 m (30 ft 8 in)|
|Width||3.38 m (11 ft 1 in)|
|Height||2.80 m (9 ft 2 in)|
|Armor||80–200 millimetres (3.1–7.9 in)|
|8.8 cm KwK 36 L/56|
|2 x 7.92 mm MG 34|
|Engine||10 Cylinder Porsche 101/1
|80 km (50 mi) (road)|
|Speed||40 km/h (25 mph)|
The VK4501 (P), also known as the Tiger (P), was an unsuccessful heavy tank prototype produced by Porsche in Germany in 1942. It was not selected for production and the Henschel design to the same specification was produced as the Tiger I. Most of the already produced chassis were instead rebuilt as self-propelled guns.
On the 21st May 1942, Henschel and Porsche at a meeting in Germany were asked to submit designs for a 45 ton heavy tank capable of mounting the high velocity 88 mm KwK L/56 gun which was derived from the German 88 mm flak gun. Both the Henschel and Porsche tanks were to be fitted with the same turret supplied by Krupp. The Porsche company worked on updating the VK3001P medium tank, Porsche's medium tank prototype, and adapted parts used on it for the new tank.
The new Porsche tank, designated the VK4501(P) was to be powered by twin air cooled gasoline Porsche Type 101/1 engines which were mounted to the rear of the tank. The twin engines would then drive two generators, one either side of the tank, which would then power two motors which would drive the tracks. But the engine along with its drive system were very prone to break down and needed almost constant maintenance to keep the tank running. This, and the tank being less maneuverable than its competitor, was the reason why Henschel's prototype, the Tiger I, was adopted for production instead. 
Ferdinand Porsche developed the spring rod roller carriage, the 12 double steel rollers on each side of the vehicle were joined in pairs. The 57 to 59 tons combat weight in combination with 640 mm wide tracks (KGS 62/640/130) produced a ground pressure of about 1.06 kg / cm.
The petrol-electric drive specially developed by Ferdinand Porsche entered "uncharted territory". It was this reason that defects were produced in the drive system. The two air-cooled 10-cylinder engines designated Porsche 101/1, which were merged respectively with a Siemens-Schuckert 500 VA generator, generated the necessary electric energy to operate the two Siemens 230 KW electric motors. In this drive system, a transmission system could be omitted, since now a 3-step speed switch took over the work. The electric motors transferred their power with a drive ratio of 15: 1 directly to the drive wheels located at the rear. The tank carried 520 liters of petrol and allowed a driving range of 80 kilometers. Two compressed air tanks in the front crew compartment area supported the tank driver during braking maneuvers.
The VK4501 (P) had its turret mounted at the front. The turret, which mounted the 8.8 cm KwK 36 and a 7.92 mm MG 34 on the same axis, was developed by Krupp, it was later modified and used by Henschel’s VK4501(H). The first eight turrets produced had lower sides and a flat roof with raised centre section to allow the gun to be depressed through larger arc.
- VK4501 (P) Test prototype
- VK4501 chassis fitted with a concrete turret to simulate the weight of the Krupp turret for testing purposes. Only 100 chassis were built.
- VK4501 (P) (Porsche Tiger)
- 5 VK4501 tanks with the Krupp turrets and 8.8 cm KwK 36 guns were produced. Only one completed Tiger(P) with chassis number 150013 saw combat service as a command tank.
- Panzerjäger Tiger (P) "Ferdinand"
- 91 existing VK4501 chassis were converted into Ferdinand tank destroyers. The work was completed in just a few months from March to May 1943.
- Panzerjäger Tiger (P) "Elefant"
- In September 1943 all surviving Ferdinands were recalled to be modified. 48 of the 50 surviving vehicles were modified with additional armour, a new commanders cupola (from StuG III) and a new ball mounted machine gun.
- Bergepanzer Tiger(P)
- A conversion of the VK4501 (P) chassis into recovery vehicles designated Bergepanzer Tiger (P). Only 3 were built.
- VK4501 "RammTiger"
- A proposed conversion of the VK4501 (P) chassis in a heavily armoured ramming vehicle armed with machine guns. 3 superstructures were completed but their fate is unkown as the project was cancelled in 1943.