On May 20, 1952, a special meeting of chief designers of tank and diesel plants was held at the Ministry of Transport Engineering with the participation of the commander of the BT and MB SA Marshal of the Armored Forces S. I. Bogdanov, which discussed the prospects for the further development and improvement of domestic armored weapons and equipment, as well as the development of new types of tanks with more powerful weapons, enhanced armor protection, high dynamic and operational performance.
And already on June 18, 1952, the chairman of the NTK GBTU, Lieutenant General V. V. Orlovsky sent ON to the Deputy Minister of Transport Engineering. Makhonin and the head of the Glavtank N. A. Kucherenko brief TTT on the design of a new medium tank. Simultaneously, copies of the TTT project were sent to the design bureaus of factories # 75, # 174, # 183 and to VNII-100.
These requirements provided for the creation of a medium tank with sharply increased tactical and technical indicators in comparison with the T-54 (in terms of armor protection, movement speed, maneuverability, armament, rate of fire, firing accuracy and reliability). According to TTT, the combat weight of the vehicle was 34 tons. The crew consisted of four people. Overall dimensions: width - no more than 3300 mm, height - no more than the height of existing medium tanks, ground clearance - no less than 425 mm. Travel speeds: maximum on the highway - at least 55 km / h, average on a dry dirt road - 35-40 km / h. Average ground pressure - 0, 65 kgf / cm². Overcoming obstacles: ascent and descent - not less than 40 °, roll - not less than 30 °. The vehicle's cruising range was supposed to be at least 350 km (using fuel in additional tanks, and the fuel stored inside the tank should be at least 75% of its total amount).
The main weapon was the installation of a 100-mm rifled tank gun D-54 (D-46TA), equipped with a stabilizer and having an initial velocity of an armor-piercing projectile of 1015 m / s. The secondary weapon included a course one (in the front of the tank hull) and 7.62 mm machine guns paired with a cannon. To protect against enemy aircraft, an anti-aircraft machine gun KPVT of 14.5 mm caliber was provided as an auxiliary weapon. The ammunition consisted of 50 unitary rounds for the cannon, at least 3000 cartridges of 7.62 mm caliber and at least 500 cartridges of 14.5 mm caliber.
The armor protection of the frontal and side parts of the hull and turret, in comparison with the armor protection of the T-54 tank, had to be increased by 20-30%.
To ensure continuous all-round visibility, a commander's cupola with a viewing device with a stabilized field of view was mounted above the tank commander's workplace. A sight of the TSh-20 type served for aiming the gun at the target. In addition, it was envisaged to use a rangefinder or a rangefinder sight (if a rangefinder was placed with a tank commander, the commander's device was not installed in the tank).
The power plant was supposed to have a diesel or a blade-type engine (GTE. - Author's note). At the same time, the value of the specific power should have been at least 14.7 kW / t (20 hp / t), and the transmission of the machine should ensure a continuous change in gear ratios in a wide range, good agility, the most complete use of engine power and ease of control. …In addition, the possibility of using a muffler to reduce the noise (if necessary) created in the process of exhausting engine exhaust gases was not excluded. Mandatory was the requirement to be able to overcome water obstacles up to 5 m deep along the bottom.
For external communication, it was envisaged to install a radio station of the RTU type, the installation of which was carried out in the dimensions of a 10RT radio station.
The serviceability of the tank was to be ensured in various climatic conditions in the ambient temperature range from -40 to + 40 ° C and strong dustiness within the warranty period of at least 3000 km.
In connection with the great complexity of the tasks set, the Ministry of Transport Engineering decided to conduct a design bureau of plants and VNII-100 of a preliminary constructive study of layout schemes for a new tank to identify the possibility of meeting the requirements of GBTU. The main hopes connected with the fulfillment of the assigned tasks were pinned on the design bureau of plant No. 75, headed by A. A. Morozov. According to his recollections, already in December 1952 the Kharkov project of a new medium tank received the code "Object 430". Despite the involvement in the preliminary study of the layout of the new medium tank KB factory # 174, this task was subsequently removed from it due to its workload with the creation of the previously mentioned ACS "Object 500" and "Object 600", as well as other samples of armored vehicles and weapons on their base.
In accordance with the requirements of the design bureau of plants No. 75, No. 183 and VNII-100 during 1952 - early 1953. completed the preliminary studies of a new medium tank, in the design of the armor protection of which the recommendations of the TsNII-48 were taken into account, obtained during the development of the armor protection schemes of the preliminary design of the T-22sr medium tank and the results of shelling the hull and turret of the A-22 model.
Consideration of projects of a new medium tank took place at the Ministry of Transport Engineering on March 8-10, 1953.
The report on the project of a medium tank of the VNII-100 design, which later received the name "Object 907" (project manager - K. I. Buganov), was made by the director of the institute P. K. Voroshilov. In this project, the hull of the tank was made cast and provided a larger booked volume than that of the T-54 medium tank and the experimental heavy Object 730 (T-10). It was supposed to install a longitudinally located shortened V12-5 diesel engine with a power of 551 kW (750 hp) with an ejection cooling system and use the components and assemblies of the T-54 and T-10 tanks on the machine.
The main weapon used was the 100-mm D-10T tank gun, but the option of installing the 122-mm M-62 tank gun was also envisaged. The armor protection of the turret with large angles of inclination was equivalent to the armor protection of the T-10 tank. In general, the armor protection of the vehicle was increased by 30% compared to the armor protection of the T-54 tank. At the same time, the driver was located in the hull under the turret shoulder strap.
The vehicle's transmission was offered in two versions - hydromechanical and mechanical (similar to the T-54 and T-34 tanks). In the undercarriage (in relation to one side), a six-roller scheme was used.
The estimated combat weight of the tank was 35.7 tons.
The project of a medium tank, developed by the design bureau of plant No. 183, was reported by the project manager - deputy chief designer Ya. I. Ram. The layout of the machine was based on a combined version, which combined the front part of the T-54 tank hull and the rear part of the T-34 with a longitudinal arrangement of a 449 kW (610 hp) diesel engine and extensive use of T-54 units and assemblies. It should be noted that in the process of working on the project in the design bureau, various layout options were considered: with the landing of the driver in the turret and body of the machine; with front and rear turrets. However, all of them did not provide a significant reduction in the mass of the car in comparison with the accepted option.
experimental tank diagrams object 907
The installation of the 100-mm D-54 tank gun as the main weapon made it possible to reduce the height of the tower by 83 mm. Due to the use of a new engine with a lower height than that of the B-54 diesel, it was possible to reduce the height of the body by 57 mm and to place an ejection cooling system above the engine. Due to the increase in the temperature of the coolant to 120 ° C, the dimensions of the radiators of the cooling system were reduced by 1.5 times. These measures allowed on both sides of the engine to carry out the stowage of ammunition for the gun. A further decrease in the height of the hull limited only the position of the driver in the control compartment.
The increased power of the engine ensured that the specified travel speeds were obtained. The undercarriage used support and support rollers of a smaller diameter with external shock absorption. Suspension elements were removed from the hull due to the use of plate torsion bars, which ensured its satisfactory performance.
The estimated combat weight of the vehicle compared to the T-54 tank was reduced by 3635 kg (of which: for the hull - by 1650 kg, the tower - by 630 kg, for the engine installation - by 152 kg), and the frontal armor was increased by 19%, sides of the tower - by 25%.
In the process of discussing the project, the chief designer of ChKZ for engine building I. Ya. Trashutin expressed great doubts about the possibility of creating a B-2 engine with a capacity of 449 kW (610 hp) without the use of supercharging. In his opinion, one could really count on 427 kW (580 hp) naturally aspirated and 625 kW (850 hp) supercharged. However, at present, ChKZ could not deal with new engines due to the heavy load of mass production. As an alternative, it was proposed to abandon water cooling and switch to air cooling. Use engine exhaust gases for ejection.
According to E. A. Kulchitsky, in terms of armament, armor protection and dynamics, things seemed to be safe from the point of view of the TTTs being asked. However, they were obtained on the basis of an unreal engine with a short stroke and high temperatures. In addition, the air-cooled engine overheated in summer and difficult to start in winter. The proposed design of the undercarriage could not provide the tank with a speed of 35 km / h on a country road: the external rubber shock absorption of the rollers would not have withstood, since the expected increase in speed was achieved only by increasing the speed of the roller. Therefore, there was no reason to reduce the diameter and width of the rollers. A fundamentally new chassis was needed.
Due to the fact that in the presented projects of new tanks (in addition to VNII-100, factories No. 183 and 75 put forward their projects), the tactical and technical requirements of the GBTU were not fully worked out, the Ministry of Transport Engineering decided to continue the work. In addition, in March 1953 the Ministry of Heavy and Transport Engineering (since March 28, 1953, according to the decree of the Council of Ministers of the USSR No. 928-398, the Ministry of Transport Engineering became part of the Ministry of Heavy and Transport Engineering (headed by V. A.) in accordance with the requirements of the GBTU for a new medium tank, he issued an assignment to diesel plants to develop an engine for it.
Based on the consideration of projects of preliminary layouts of the new medium tank TTT, in May 1953, they were clarified and finalized in the NTK GBTU, agreed with the Ministry of Heavy and Transport Engineering and in September of the same year they were sent to factories No. 183 (plant director - I. V. Okunev, chief designer - L. N. Kartsev), # 75 (plant director - K. D. Petukhov, chief designer - A. A. Morozov) and VNII-100 (director - P. K. Voroshilov) to present pre-draft designs by January 1, 1954
The revised "Indicative brief tactical and technical requirements for the design of a new medium tank", in particular, noted:
1. Combat weight - 36 tons (estimated weight according to the technical design no more than 35.5 tons).
2. Crew - 4 people.
3. Overall dimensions: width along the tracks - 3300 mm (it is desirable to have the width of the hull no more than 3150 mm), height - no more than the height of the T-54 tank, the height of the fighting compartment along the loader in the light - not less than 1500 mm (to ensure the convenience of the loader), height hulls in the driver's seat (in the light) - 900 mm (while maintaining the landing height in the driver's seat not less than in T-54), ground clearance - not less than 425 mm.
4. Armament:
a) cannon type D-54 stabilized, with ejection blowing of the bore, caliber 100mm, initial velocity of an armor-piercing projectile - 1015 m / s.
b) machine guns - coaxial with a cannon - SGM caliber 7, 62 mm;
- course - SGM caliber 7, 62 mm;
- anti-aircraft - KPVT caliber 14, 5 mm.
5. Ammunition: rounds for the gun - at least 40 pcs., Cartridges 14, 5-mm - 500 pcs., Cartridges 7, 62-mm - 3000 pcs.
6. Armor protection:
a) the forehead of the hull - 120 mm with an angle of inclination of 60 °, the side - 90 mm (exceeding the speed protection by 10%);
b) the forehead of the tower - 230 mm, normalized.
7. Running performance and cross-country ability:
a) specific power - not less than 16 hp / t;
b) specific pressure without immersion - 0.75 kg / cm²;
c) travel speed: maximum on a highway - 50 km / h, average on a dry dirt road - 35 km / h;
d) ascent and descent - 35 °;
e) roll (without turning) - 30 °;
f) cruising range on the highway - 350 km;
g) fuel supply: total - 900 liters, reserved - 650 liters;
h) overcoming water obstacles with a depth of 4 m.
8. Engine:
a) the main option - a shortened one based on V-2 or horizontal with a capacity of 580 hp;
b) a promising option - a new engine with a capacity of 600-650 hp. with reduced dimensions and a warranty period of 400 hours.
9. Transmission - the simplest to manufacture, easy to operate, reliable in operation.
10. Chassis:
a) suspension - any individual, providing maximum average speeds;
b) rollers - preferably without external rubber, but with minimal noise when driving;
c) caterpillar - cast fine-link;
d) shock absorbers - providing the ability to move at predetermined speeds and fire the descent.
11. Aiming and observation devices:
install a turret with an all-round view at the tank commander; install a command observation device with a stabilized field of view in the hatch cover;
install a TSh-2 type sight or a TP-47 type periscope sight at the gun commander;
the tank must be equipped with a rangefinder or a rangefinder sight (if a rangefinder is installed, the command device is not installed in the tank).
12. Radio station - tank type RTU - in the dimensions of a radio station 10RT.
13. The tank must be reliable and trouble-free in operation in various climatic conditions at ambient temperatures from -45 ° C to + 40 ° C, as well as in dusty conditions.
14. Warranty tank service life - 3000 km. Note. The service life before repair should be 5000 km."
On the basis of these short TTTs, the NTK GBTU compiled and agreed with the Ministry of Heavy and Transport Engineering thematic cards for the ROC on the creation of a new medium tank, which in November 1953 were sent out by the design bureaus of factories No. 183, No. 75 and VNII-100. approximate short TTT, in these thematic cards the ammunition for the main weapon was increased to 45 shots, the penetration rates and course angles of shelling of the armor plates of the hull and turret were clarified, the maximum speed of movement on the highway was increased to 55 km / h and the engine of the B-2 s type was determined generator with a power of 5 kW.
It was allowed to clarify the tactical and technical characteristics of the tank after reviewing the draft designs.
The approximate cost of the work was set at 1 million rubles, of which 600 thousand rubles were allocated for 1954, and 400 thousand rubles for 1955. The activities of factories # 75 and # 183 were financed by the USSR Ministry of Defense. The customer from this ministry was NTK GBTU. VNII-100 conducted its development at the expense of funds allocated by the Ministry of Heavy and Transport Engineering on the topic of determining the possibility of creating a cast hull of a medium tank.
The chief designer and, accordingly, the design bureau and the subsequent manufacturing plant were determined on a competitive basis after considering the draft designs.
Further work on the creation of a new medium tank was carried out on the basis of the decree of the Council of Ministers of the USSR No. 598-265 of April 2, 1954. The ROC plan for 1954 on weapons and military equipment opened a new topic - the development of a medium tank with increased tactical and technical indicators in compared with the T-54 (in terms of armor protection, movement speed, maneuverability, armament, accuracy and reliability). Plants No. 75, No. 183 and VNII-100 were identified as the main executors of this R&D project.
The developed pre-sketch projects of a new medium tank designed by the design bureau of plant No. 75 ("Object 430"), No. 183 and VNII-100 ("Object 907") were considered twice during 1954 (February 22 - March 10 and July 17-21). ministry and STC GBTU. As a result, NTK GBTU put forward a number of additional requirements and comments to the project of a new medium tank, sent on September 6, 1954 to the design bureaus of factories and VNII-100.
As for the further participation of VNII-100 in the creation of a new medium tank, then during 1954-1956. he, together with TsNII-48 and his Moscow branch, carried out a number of experimental studies on the development of armor protection for the Object 907 tank. Along with this, prototypes of the hull (in the mass of the hull of the T-54 tank) and the turret were made. Conducted in April 1955 at the NIIBT proving ground, shelling tests of the experimental armored hulls of the Object 907 tank, made both in one-piece and in a welded version - from large cast units (the upper part is rolled, the lower frontal and aft parts are cast, with this cast armor had curvilinear shapes of variable cross-section with large design angles of inclination of parts), showed a significant increase in anti-projectile resistance compared to the body of the T-54 tank, especially in protection against damage by cumulative projectiles of 76, 2 and 85 mm caliber, as well as PG- 2 and PG-82 of the RPG-2 hand-held anti-tank grenade launcher and the SG-82 heavy grenade launcher.
The joint work of TsBL-1 and TsNII-48 to study the feasibility of manufacturing cast armored hulls for a new medium tank began in 1953. During 1954, research was carried out for optimal forms of armor protection in relation to the layout of the Object 907 medium tank, working drawings were issued towers and hulls in three versions: one-piece and two welded. Moreover, the first version of the welded hull was assembled mainly from cast armor parts (with the exception of the upper frontal sheet, roof and bottom), and the second had sides made of shaped rolled products of variable thickness. At the same time, technological processes of welding and assembly of housings were developed, laboratory studies were carried out on the technology of armored rolling of sheets of variable thickness, and model equipment for a one-piece hull was manufactured. However, at the end of 1954, only the tower and the hull, manufactured according to the third version, were manufactured and submitted to the NIIBT test site for testing by shelling.
With an equal weight of the armored hulls of the T-54 tank and the Object 907 tank, the latter showed an advantage in tests in protection against armor-piercing shells when firing at the front and sides. The heading angle of non-penetration by an armor-piercing projectile for the sides of the Object 907 tank was ± 40 °, and for the T-54 tank - ± 20 °. In the joint decisions of the Academic Council of TsNII-48 and VNII-100 of July 28, 1955, as well as in the decision of the Ministry of Transport Engineering of July 16, 1956, it was pointed out the significant advantages of the new type of booking and the need for its implementation in tank building. However, due to the possibility of performing the TTTs that were in force at that time to protect tanks from being hit by conventional armor-piercing shells by the old constructive types of booking and the lack of TTTs to protect tanks from cumulative ammunition, tank design bureaus of factories refrained from the widespread use of fundamentally new constructive forms of armor protection for the hull and turret of a tank. associated with the need to use large castings of a complex profile.
Object 907 did not go into production: it was let down by its excessive "advancement". During consideration at the plenum of the scientific and technical committee of the GBTU, it was indicated that the project of object 907 with a hydromechanical transmission, a new hull and an improved turret meets the tactical and technical requirements and surpasses the T-54 tank in basic parameters, but due to the complexity and incompleteness of the design of a number nodes and mechanisms cannot be accepted. The plenum recommended to send a draft design of the object 907
"… to factories No. 75 and 183 for use in the development of technical projects for a new medium tank."
The only thing that was proposed to continue was testing the armor-piercing and cumulative shells of the armored hull, since this was of great importance for objects 140 and 430. By the summer of 1954, VNII-100, using the project of object 907, had already developed a draft of an armored hull in relation to the layout of the Tagil tank.
Object 907 was planned to be made mainly of armor casting. The direct developers of the design and technology were the Moscow branch of VNII-100 (in the recent past, the Central Armor Laboratory) and TsNII-48, which is in the Ministry of the Shipbuilding Industry, but continues to cooperate with tank builders.
The advantages of casting technologies in the manufacture of armored structures have long been known and widely used. Their main advantage in the joint report of VNII-100 and TsNII-48 for 1955 was presented as follows:
"Cast armor expands design capabilities in the creation of armor protection structures of any shape and provides the necessary anti-projectile resistance of individual areas of the structure, depending on the tactical and technical requirements."
The main disadvantage of cast armor, namely: lower durability compared to katana, at large angles of encounter with shells, from 45 degrees or more, practically did not affect.
In the USSR, the joint work of two institutes to study the feasibility and feasibility of manufacturing cast armored hulls or their assemblies for a new medium tank began in 1953. In 1954, research was continued in the form of a broader topic "Development of armor protection for a promising medium tank." During the year, research was carried out jointly for the optimal forms of armor protection in relation to the layout of a medium tank, working drawings of the turret and hull of a medium tank object 907 were issued in three versions: one-piece and two welded, and if the first was assembled mainly from cast parts (with the exception of the upper front plate, roof and bottom), then the second also had a board made of profile rolled products of variable thickness. At the same time, technological processes of welding and assembly of hulls were developed, laboratory studies were carried out on the technology of rolled armor with variable thickness, and model equipment for a one-piece hull was manufactured. However, only the body of the last third type was able to manufacture and submit to the Cuban firing range in 1954.
At the beginning of 1955, tests were carried out on a body welded from cast parts. On the whole, it met the requirements for new medium tanks and significantly surpassed the T-54 in anti-cannon resistance. After that, a shortened one-piece hull was made and fired upon, which is a closed loop of natural elements of the bow, side and stern parts. It turned out that the developed technological process ensures the production of high-quality casting with the planned projectile resistance. By the end of the year, it was planned to cast a full-size hull with changes based on the results of the first tests; its shelling was scheduled for the beginning of 1956.
At the same time, it became obvious that modern cumulative ammunition, for example, 85-mm non-rotating projectiles, quite confidently penetrates the frontal protection of object 907, regardless of the manufacturing technology. The tower, for example, was struck at any course angles. More or less, only the frontal parts of the hull held the blow, but only in those parts that had the maximum angle of inclination to the vertical.
TTX tank object 907 (design data)
