IS-1 / JS-1 (Josef Stalin)

History

The IS-1 stemmed from the Soviet Army's need for a more powerful tracked weapon system to counter increasingly powerful German tanks - especially the new Panther and Tiger I series released in late 1942. The KV-1- and KV-2 series had limited responses, but these ultimately proved too unwieldy in the heat of battle, and were generally not highly regarded by their crews - especially the top-flying KV-2. Both lacked the necessary mobility required by the changing fronts of modern WWII warfare and proved costly in the mass production required at the time.

Therefore, Soviet engineers started designing the "KV-85" tank as an interim solution, and at the same time a new initiative called "KV-13" was launched.

The KV-13 program produced the "IS-85" prototype (Object 233) with heavier armor, enhanced all-around protection, and heavier main gun armament. The armor was specially designed to counter German 50mm anti-tank guns. Their weight limitations were limited to those of the original KV-1 model to keep the design under control. The primary armament is an 85mm D-5T series main gun mounted on a movable turret system on a low tracked landing gear.

Six wheels with twin tires are provided on each side of the track. The drive sprocket is at the rear and the chain idler is at the front. Three track return rollers support the upper part of the track. The external fuel tank bracket is mounted on the rear side of the vehicle body.

The turret is kept very forward in design (like the T-34 medium tank) and has thick, curved armor and some sloping. A commander's cupola is mounted on the top left rear of the turret. A 7.62mm DT coaxial machine gun was mounted next to the main gun, and a defensive rear-facing DT machine gun was mounted on the rear wall of the turret, offset to the left of the turret. Another DT machine gun was mounted on a bow bracket. The entire vehicle stores 59 rounds of 85mm shells and is loaded with 2,520 rounds of 7.62mm machine gun ammunition.

Power is provided by a V2 IS 12-cylinder engine with 520 hp. Top speed is 23 mph, while range is limited to 93 milesboth numbers taking into account ideal conditions. The IS-1 is flown by a crew of four, including a driver, a tank commander, a gunner and a loader/machine gunner.

After hasty trials, the IS-85 system entered mass production as the "IS-1" in 1943. It also marked the beginning of a long line of successful and powerful "Joseph Stalin" heavy tanks that proved crucial in the final years of the war and even in the Cold War.

Such was the Soviet need for powerful heavy tanks, the KV-1, KV-2 and KV-85 tanks fought until the end of the war, and the IS-1 line itself developed as the war progressed.

The IS-1 was inevitably (and soon) replaced by the more familiar IS-2 series and its A-19 series 122mm guns. The IS-3 appeared in late 1944 as an improved IS-2. Only 200 IS-4 examples followed, and there were no IS-5 designs. Instead, the IS-6, like the IS-7, started an abandoned design project. The line culminated in the Cold War-era IS-10 model, Joseph Stalin's last heavy tank line, at a time when the world was transitioning to main battle tanks - making the heavy tank concept somewhat obsolete.

However, much of the lessons learned from fighting the IS series in WWII were put into practice in the development of a new generation of Soviet tanks.

In addition to the Russians, IS-1 operators include Slovakia, Ukraine and Belarus.

Specification

Basic

Roles

Dimensions

Performance

Performance

for everyone else in our database)

Armor

59 x 85mm bullet

2,520x7.62mm ammo

Changes