Experienced heavy tank "Object 277" was designed in Leningrad, in the design bureau under the leadership of Zh. Ya. Kotina in 1957. Its design used some of the technical solutions implemented in the IS-7 and T-10 tanks.
The 55-ton tank had a classic layout. The hull had a cast frontal part and curved side plates. An optical rangefinder sight was installed in the extended front part of the cast turret, and a mechanized stacking of shots for the gun was installed in the elongated aft part. The tank's crew consisted of 4 people.
The technical design of the 130-mm gun M-65 was carried out by the design bureau of plant No. 172 under the direction of M. Yu. Tsirulnikov in the spring of 1956, and in June 1956, testing of prototypes of guns began.
The barrel of the M-65 gun consisted of a monoblock tube, a casing, a breech, an ejector and a target muzzle brake. The gun is loaded separately-sleeve, charge weight 12, 2 kg, mechanical feed, electromechanical rammer. Since the gun was not put into service, its official rate of fire is absent, but the option of supplying a permissible rate of fire of 10-15 rds / min was being worked out. The gun was equipped with a two-plane stabilizer "Groza", a TDPS rangefinder sight and a TPN-1 night sight.
It should be noted that, in fact, the design of new heavy tanks began in January 1955, even before the publication of Decree No. 1498 837. The tank was developed in two versions: ob. 277 and ob. 278 with a gas turbine unit (GTU). Both options differed only in engine compartments. … In rev. 277, it was supposed to use a modernized version of the V-2 diesel with a capacity of 1000 hp as the engine. or the M-850 marine diesel engine, serially produced by the Leningrad plant. Voroshilov. Kotin preferred a tit in his hands and was not mistaken - a modernized sample of the V-2 engine designed by I. Ya. Trashutina was released only in 1958, and then in prototypes. And ob. 277 received an excellent twelve-cylinder diesel engine, which developed a power of 1090 hp. at 1850 rpm.
Diesel M-850 was located along the axis of the tank, and on the sides were located the ejectors of the cooling system, under them - oil and fuel tanks. An air cleaner was installed in the front of the engine compartment. In the stern, between the final drives, an eight-speed planetary gearbox with ZK-type steering mechanisms and a hydraulic control system were placed.
The road wheels of small diameter with internal shock absorption were structurally similar to the rollers of the first samples of KB tanks and gave savings in machine weight. This made it possible to increase the length of the torsion bars due to the extension of the heads inside the support beams to the outer edge of the rollers. On the extreme supports, telescopic hydraulic shock absorbers were provided. Long torsion bars in combination with hydraulic shock absorbers provided the heavy tank with sufficient smoothness and made it possible to count on high speeds when driving over rough terrain and uneven ground.
The armor ob. 277 withstood almost point-blank shots from the 122-mm D-25T cannon. The 76 - 122-mm cumulative shells and rocket-propelled grenade launchers, which were in service by 1957, did not penetrate it either.
For the first time, anti-nuclear protection elements were installed on ob. 277. For the first time in domestic practice, the TPD-2S rangefinder sight was adopted, which combined a sight stabilized in two planes with an optical rangefinder with a base tube, located outside across the tower. The creation of the TPD-2S was preceded by lengthy tests carried out jointly by the Kirov plant with the Krasnogorsk mechanical plant on an experimental tank ob. 269 in 1953-1954.
Object 277 was equipped with a semi-automatic cassette loading mechanism. The shells were placed vertically in a closed chain conveyor located at the rear of the fighting compartment on a rotating floor beyond the recoil of the gun, and the shells were laid horizontally on a special conveyor installed in the turret recess. The projectile was automatically turned to a horizontal position and fed to the ramming line. Further, the projectile on the tray was connected to the sleeve, after which the entire shot in one stroke of the rammer was fed into the chamber of the gun.
