The KV-1 Heavy Tank of the World War 2 period (1939-1945) proved as important as any other tank product for the Soviet Union. Engineers consistently worked on the design to extract any amount of improvement as desperation during the war set in. Heavy armor protection was a hallmark of the series in the early-going but reliability and cost led to a production total of 5,219 units before the end - the T-34 Medium Tank proving a much viable alternative.
One of the KV-1 project offshoots became the "KV-9". The project was spurred by the German invasion of the Soviet Union in June of 1941 (Operation Barbarossa) which cost the Red Army much in armor and man power and Germany steam-rolled through the Soviet countryside en route to Moscow. That fall, Soviet Army authorities looked at the prospect of a heavy-class, assault-minded tracked vehicle to demolish enemy bunkers and other battlefield fortifications at range.
Kirov Works (Factory No.100) of Chelyabinsk took the framework of the KV-1 and mated it with a revised turret form housing a modified version of the 122mm D-30 towed field howitzer - this becoming the 122mm "U-11" of short-barreled form. The turret sported frontal protection of 135mm thickness, making it highly impervious to most any German field or tank gun (the famous "88" FlaK gun was of chief concern).
The prototype, designated internally as "Object 229" - was unveiled during April of 1942 and evaluations of the mating soon followed as the war continued to rage on. Plans were laid down for a pre-series batch of ten tanks, to be designated as "KV-9", but this endeavor eventually fell to naught - just the sole prototype being completed as the Army held reservations about accuracy-at-range of the main gun (mainly due to its inherently low muzzle velocity) and quickly lost interest amidst other growing needs.
The KV-9's turret and gun were later reconstituted in a KV-13 Medium Tank project (known as "Object 233") in which the component was mated to the established running gear and hull of the KV-13 to produce the "IS Model 2". Again, a single prototype was evaluated with success in 1943 but this proposed form eventually lost out to the competing "IS Model 1" offering.
As completed, the KV-9 was to house a crew of four and featured the 122mm U-11 howitzer as its primary weapon with up to 3 x 7.62mm DT machine guns for self-defense and anti-infantry work. Its weight reached 47 tons and the vehicle sported a running length of 6.76 meters, a width of 3.3 meters, and a height of 2.8 meters. Power was from a single W-2K 12-cylinder diesel-fueled engine of 600 horsepower driving a standard track-and-wheel arrangement featuring six double-tired road wheels to a hull side. The drive sprocket was positioned to the rear with the track idler at front. Three large track-return rollers were used to each hull side.
Performance included a top road speed of 30 kmh, an offroad speed of 19 kmh, and an operational range out to 230 kilometers on road. Fording depth reached 1.5 meters.
On the whole, the vehicle retained the form and function of the original KV-1 complete with its rear turret overhang, rear-mounted engine compartment, and workmanlike appearance.