The Double Barrelled VT Tanks
In the 1970s Germany investigated a novel approach to tank design when attempting to replace its Leopard 1. This vehicle was small, extremely mobile and, most importantly, carried two 120 mm guns.
It was named the Versuchsträger, meaning "test-bed", but was known simply as the VT tank. The motivation behind the VT tank was to increase first hit probability by increasing the number of guns on the vehicle — more guns equals a higher chance of hitting something, right?
Like the Swedish S-tank, the VT completely ignored the conventional tank design philosophy of a hull and rotating turret.
Also, like the S-tank, the VT was the main battle tank (MBT), not a tank destroyer, even though it followed many design principles of older tank destroyers.
However, despite taking a radical approach to addressing the requirements of MBTs, the VT tank offered too few advantages over normal designs to justify its adoption into service.
Background
Today, the generally accepted layout of a tank is a hull, two tracks and a turret. This is popular because it enables a tank to perform well in many areas.
However, because this is the "standard" layout, it is imperfect. Many other less conventional, more specialised approaches have been attempted.
For example, oscillating turrets enable a small tank to carry a large caliber gun. Casemate-type vehicles lack a turret but are much lighter and can also carry a large gun.
The Swedish S-tank omitted a turret and independent gun movement entirely, instead locking the gun to the hull and using the hull itself to aim.
Similarly, the VT double barrelled tank broke many design traditions. It was a turretless, twin-gun design developed in West Germany in the 1970s.
At this time, the Leopard 1 was due for a replacement and the VT tank was seen as a novel design, but one with potential. The VT tank was all about efficiency.
It was well established that in tank-on-tank engagements, whoever fired first would likely win. First hit probability (the likelihood of your first shot actually hitting the target) is crucial in this situation.
Stabilisers and fire control systems had greatly improved first-hit probability since WWII, but they needed to do even better for a suitable replacement for the Leopard 1.
The VT aimed to increase first hit probability by literally having more guns. The idea behind this was that you have a higher chance of hitting the target with two shots than you do with one.
Mobility was also extremely important to the project. Instead of a turret, the VT housed its guns in a casemate style hull, similar to the WWII-era Jagdpanzers. This reduced both the tank’s size and weight, greatly improving mobility and survivability.
VT Tank Design
The VT double barrelled tank was built upon the chassis of the recently cancelled MBT-70, albeit slightly shortened.
By removing the turret, the VT could save considerable weight and better facilitate mounting two large calibre main guns.
Two test vehicles were built, VT 1–1 and VT 1–2.
The VT 1–1 was built by the German company Maschinenbau Kiel (MaK) in 1974 and was armed with two 105 mm guns. To operate the vehicle, the VT 1–1 contained four crew, loading each gun manually.
The following year MaK built an even beefier double barrelled tank; the VT 1–2. The VT 1–2 was equipped with two 120 mm Rh120 smoothbore guns, the same type used on Leopard 2.These cannons were tremendously powerful, so carrying two would have made the VT 1–2 a deadly force on the battlefield. The guns were fed by 6-round autoloaders, eliminating the need for a loader and increasing the guns’ rate of fire.
With this change, the crew was reduced to three — a driver, commander and gunner. All three sat side-by-side at the front of the hull. The small number of crew increased the chances of survival in the case of a penetrating hit.