WW2 Panzer construction history ep.1 - from begleitwagen to 56-ton armored vehicle - story of the Tiger tank (part.1)
The history of the Tiger tank begins in 1935 from the beginning of the development of a specialized tank engine when Maybach was asked to produce a tank engine, so that the German army could avoid using modified aircraft engines.The aim was to produce 600-700hp engines, but they wouldn't arrive in time for the DW prototypes, which were powered by the 300hp Maybach HL 120 of 1936.
Maybach HL 100 TR used on experimental Begleitwagen tanks.
In November 1936, Krupp was asked to produce a design for a turret armed with a 7.5cm gun, suitable for use on a 30 ton tank.In January 1937, when the tank design office of the ordnance department (Wa Prw 6), asked Henschel to design the chassis for a 30 ton tank.The order was issued to Henschel und Suhn, which chose not to design a new panzer from scratch, but to use ready-made developments. The heaviest German serial tank PzKpfw IV Ausf A was chosen as the initial sample, which had a mass of 17300 kg and had good reserves for modernization.At this stage the new tank was named the Begleitwagen (verstaerkt) or 'escort tank, (strengthened), suggesting that it was seen as having a similar role as the Panzer IV, the original Begleitwagen.
Begleitwagen prototype experimental chassis, summer of 1938. The spaced armour covering the idler and the muffler on the fender are visible
On 12 March 1937 the name was changed to Infanteriewagen, suggesting an infantry support role, but already 27 April 1937 the name was changed once again, this time to Durchbruchswagen (D.W.), or break-through tank.In 1939, after the adoption of the VK designation system, the D.W. became the VK 30.01 alte Konstrucktion (old design), an acknowledgement that was the precursor of the VK 30.01.D.W 1 & 2 had more similar details, a simple boxy hull and superstructure. The superstructure was the same width as the hull, so didn't overlap the tracks. The front of the superstructure was over the front road wheel. The D.W.I had cast steel road wheels with solid rubber double tires, and a 300mm track pitch. It used torsion bar suspension with cushioning to make the ride smoother. It probably had five road wheels on each side, and three return rollers.
Wooden model of the Rheinmetall B.W. This is how the tank was supposed to enter production.
The hull was built in two sections (at this point the available steel mills couldn't produce a long enough piece of rolled steel to allow for a single piece) and bolted together just to the rear of the fighting compartment. A vertical stiffener was added to strengthen the join. The turret ring had a diameter of 1500mm.The sole example was built from soft steel, 50mm thick on the front, sides and rear and 20mm thick on above and below.Steering was provided by Cletrac three stage steering gears arranged in series. Each Cletrac stage contained an idler that slowed down the track it was connected to by a fixed amount, produced a different fixed turning circle.
The front of the improved Begleitwagen. The large transmission access hatches are visible. This solution made the transmission easier to service, but was not the greatest for shell resistance.
The D.W.2 have had one piece sides, or they might have been introduced on the VK 30.01 (H). There were five road wheels on each side, constructed from steel, with solid rubber double tire, supported on torsion bars.The D.W.2 used a new steering system. The D.W.1 had used three Cletrac steering gears, arranged in series, on each track. The D.W.2 retained the first Cletrac stage, which produced one fixed turning circle without losing engine power to brakes (using an idler that could be turned on or off to alter the output speed of the transmission).This was connected to a standard three stage differential, presumably with further steering control provided by brakes applied to the tracks, as in simple differential steering systems.The new system rotated in the opposite direction to the system used in the D.W.1, so the final drive, brakes, gear box and even the torsion bars needed to be modified. The final drive was modified, reducing the gear reduction from 1-21.5 to 1 to 12. The torsion bars had the soft springs used on the D.W.1 removed, and were made stronger. The track was reduced in pitch from 300mm to 260mm, and the ride was said to have been much smoother.
Externally, the first B.W. looks very similar to the PzIV Ausf. A. The similarity is misleading. The tank underwent significant changes, both on the inside and the outside, before it entered production.
The Durchbruchswagens chassis was tested during 1938.9 September 1938 Henschel was ordered to produce an improved 30 ton tank. This new design had three different names. VK 30.01 indicated that it was the first design in the 30 ton tank rank. It was also known as the D.W. neue Knostruktion (new design), and by 31 October 1940 as the Panzerkampfwagen VI (7.5cm).
B.W. II Kp converted into a bridgelayer, 1939.
The VK 30.01 (H) was the first to use interleaved road wheels.The basic layout of the tank was similar to the earlier D.W.1 and D.W.2. It had a boxy hull, with a superstructure the same width as the hull (thus not overlapping the top of the tracks). The front of the superstructure was over the front road wheel. The un-lubricated tracks were 520mm wide, and with a pitch of 160mm (shorter than on either of the D.W. models).The VK 30.01 was to be armed with the same 7.5cm Kw.K L/24 gun as used on the Panzer IV, and was to have the same crew space as the lighter tank.The main difference would be in armour, VK 30.01 was to have 50mm front and side armour, which was expected to be effective against uncapped armour piercing shells as fired by the standard German anti tank gun of the time, the 3.7cm PaK L/45.Krupp had the task of producing the turret, just as on the D.W. series. The sides of the D.W. had been made in two pieces, joined just behind the fighting compartment. The VK 30.01 had single piece sides.The VK 30.01 introduced the interleaved road wheels used on the Tiger. There were seven pairs of wheels on each side, with the second, fourth and sixth on the outside and first, third, fifth and seventh on the inside.
Heinrich Ernst Kniepkamp - the developer of the scheme of staggered placement of rollers on suspensions of German tanks.
This resulted in four rows of narrow wheels (from outside to inside in a three-four-four-three arrangement. This arrangement allowed more road wheels to fit in the same space than a non-overlapped system, and thus helped support the increased weight of the tank.However this system would also prove to be one of the weaknesses of the Tiger, as the narrow gaps between the road wheels could easily get clogged with snow and mud, and freeze solid, while any damage to an inner wheel required all of the rows of outer wheels to be removed and then replaced, a time consuming job. Suspension was provided by simple torsion bars. There were three return rollers, mounted at the top of the hull.
A VK 30.01 made from mild steel, captured at the Sennelager proving grounds near Paderborn in the spring of 1945. The vehicle was being used to test engineering equipment.
The VK 30.01 was powered by a 300hp Maybach HL 116 motor which drove a Maybach-Motorenwerk Variorex gearbox.The VK 30.01 used a new Henschel L.320 C steering gear which used epicyclic double differential steering. This had three steering speeds, and took both its steering drive (to the sun wheels) and main drive (to the annulus) from the output of the main gearbox. It gave the tank three turning radii.This was the precursor of the L.600 C and L.801 transmissions used in the Tiger, but these were more flexible systems, which took the steering drive from the input of the main gears, and the main power from the output, producing sixteen possible turning circles (two steering speeds times eight speeds).
The armour layout of the VK 30.01 as of January 1940. Later, the floor armour was reinforced.
Krupp had produced one example of the D.W. turret, although it was never mounted on either prototype. They then redesigned the turret for the VK 30.01 and the heavier VK 65.01.The two turrets were to be identical apart from side armour thickness - 50mm on the VK 30.01 and 80mm on the VK 65.01. The turret was to carry the 7.5cm gun, a coaxial machine gun, and have a gun port for a second rear-firing machine gun.
The first tank of the zeroth batch, captured by the British in the spring og 1945. This was the only tank from the D.W./VK 30.01 family to receive a turret.
Towards the end of 1939 Krupp was given an order to build four hulls - one based on the D.W. layout, as the VK 3001 alte Konstrucktion for use in armour penetration tests, and three VK 30.01 neue Konsturktion (new design) hulls with armoured superstructures, for driving trials. By the time the target hull was complete in September 1940 it had been modified to the new standard, and it was used to test the armour against 3.7cm anti-tank gun. The three new design hulls were completed by 1940.