Prior to, and during, World War 2 (1939-1945) there were a flurry of light tank designs emerging from the Soviet Union. The Army sought to modernize its tank fleet during the 1930s and this produced such types as the classic T-26 Light Tank and BT Fast Tank series of combat vehicles - both of which went on to see combat service in the conflict. Even into the early stages of the war, before the famous T-34 Medium Tank had officially planted itself as the mainstay of the Soviet Army, there was progress being made on newer, more modern light tank systems - such was the need for any and all tracked-and-armored war machines to stave off defeat at the hands of the Germans.
From 1941 to 1942 design work was had on what would become the "T-70" light tank (detailed elsewhere on this site). The type entered service in 1942 and over 8,200 were produced for fighting in World War 2. The vehicle sported a 45mm main gun with 7.62mm coaxial armament and was driving by paired GAZ-202 gasoline-fueled engines offering a combined output of 140 horsepower (2x70hp). The vehicles were relatively fast with road speeds reaching 45 kmh, had a range out to about 360 kilometers, and housed a crew of two - the driver in the hull and the commander/gunner in a one-man traversing turret set over the hull superstructure.
An attempt was made to streamline the function of this vehicle by addressing several of its inherent limitations - namely in the development of a new two-man turret. However, this installation required the hull superstructure to be complete reworked and the added weight, in turn, called for additional drive power. On top of all this, Army authorities required the main gun to now be able to engage targets at higher elevations better aid urban fighting as well as counter the threat posed by low-flying aircraft.
The existing framework of the T-70 simply could not support these changes so "Object 080" was drawn up to cover a new light tank design - the "T-80". The hull was appropriately widened to better accept the turret and turret ring and the main gun's elevation span was accordingly addressed to fulfill the stated Army requirement. The new tank was unveiled in December of 1942.
The T-80 more or less existed as an advanced form of the earlier T-70 for it did not widely depart in its form-and-function, nor battlefield role, all that much. The hull superstructure continued use of angled facings for basic ballistics protection and the engine was fitted to the rear of the hull proper - leaving the middle and forward sections cleared for the fighting compartment. The turret was set over midships with a clear 360-degree traversal possible over the entire hull of the tank. There were five road wheels to a hull side with the drive sprocket at front and the track idler at rear. Three track-return rollers were in play to help guide the upper span of track links.
The greatest deviation from the T-70 was the introduction of the two-man turret which offered greater tactical advantages on the battlefield as well as reduced workloads for the commander (he was no longer required to command the vehicle and train/fire/reload the main armament). Armor protection reached up to 45mm thickness at the most crucial facings, namely the front and sides of the hull, but this only provided safety from small arms fire and artillery spray. As finalized, the vehicle sported an overall length of 4.29 meters, a beam of 2.5 meters and a height of 2.2 meters. Weight reached 11,600 kilograms.
The installed GAZ-203F gasoline-fueled engine was nothing more than a pairing of 2 x GAZ 80 Otto 6-cylinder units resulting in a combined output of 170 horsepower to drive the track-and-wheel arrangement. Road speeds could reach 42 kmh (slightly slower than the T-70) and range was out to 350 kilometers (10 km less than the T-70) on prepared roads.
Reliability of the paired engine sets ultimately delayed large-scale serial production of the T-80 heading into 1943 for useful numbers were only finally being seen in July of that year. By this time, the T-34 was proving itself a war-winner and the Army quickly moved away from its commitment to the T-80 and other light tanks for that matter. The war would be fought, and won, by the Red Army through grit, battlefield heroics, and a reliance on medium and heavy tank types offering exceptional armor protection and ever-larger main gun calibers.
About eighty or so T-80 Light Tanks were built before the end of 1943.