In case the enemy sets up mine-explosive obstacles, the troops need various means to make passages for equipment and infantry. To date, a large number of different mine-sweeping systems have been created, using a variety of methods to combat obstacles. One of the most interesting methods of removing mines from the path of the advancing troops was proposed to be used in the project of the turbojet minesweeper "Object 604".
In the early sixties, the Soviet army wished to receive new specialized equipment capable of making large passages in enemy minefields. Existing roller trawls, etc. the systems did not fully meet the updated requirements, which is why it was decided to create a completely new model of armored vehicles. On October 25, 1961, the requirements of the military department were enshrined in a new decree of the Council of Ministers of the USSR. In accordance with it, in the foreseeable future, the industry was supposed to present a self-propelled minesweeper vehicle built on the chassis of a serial medium tank.
Turbojet minesweeper "Object 604"
The development of a promising project was entrusted to the Omsk design bureau OKB-174. A. A. was appointed chief designer. Morov, leading designer - A. A. Lyakhov. In accordance with the existing designation system for new projects, the prospective minesweeper received the working name "Object 604". In addition, an additional name was proposed, indicating the purpose of the machine - "Turbojet mine minesweeper" or TMT.
A promising engineering vehicle was to be built on the chassis of the T-55 medium tank, by that time well mastered by the army of the Soviet Union and distinguished by fairly high characteristics. All unnecessary units should be removed from the existing chassis, after which it should have received two turbojet engines of the R11F-300 type. It was planned to equip the engines with a special nozzle device that provides trawling and ejection of soil together with mines outside the passage being made.
The supposed operating principle of the TMT / Object 604 machine was quite simple. Moving through a minefield with turbojet engines turned on, she was supposed to direct jet streams to the ground and literally blow it off along with the installed mines. The power of the engines used, according to calculations, made it possible to get rid of both light anti-personnel and heavier anti-tank mines. Unlike the existing track trawls, the new engineering vehicle was supposed to create continuous passages up to several meters wide, suitable for use by people and equipment.
Retrofitting an existing tank using additional jet engines was not in itself a difficult task. More difficult was the issue of creating a nozzle device capable of trawling across the entire width of the vehicle body and beyond. As far as is known, for this, at an early stage of the Object 604 project, a prototype with an experimental set of equipment was designed and built.
As the surviving photographs show, already at this stage, some features of the layout of the future minesweeper were identified. So, turbojet engines were placed on the stern of the fenders, for which the corresponding holding devices appeared on them and on the hull. In front of the engines, installed with the nozzle forward, were placed metal boxes necessary to distribute the flow of reactive gases. The experimental project proposed the use of two rectangular pipes extending from the boxes to the front of the machine. There was a bell at the front end of each pipe. In addition, an additional round-section pipe ran along the left side of the hull. Its front part was located with a slope, because of which the gases escaping from it had to blow the soil to the side.
An experimental sample, with the help of which the composition of special equipment was tested
A similar prototype was tested and confirmed the fundamental possibility of trawling mines using jets of reactive gases. At the same time, the existing pipes and nozzle devices did not show the required operating efficiency. Taking into account the test results, a new version of the project was created. It provided for a significant processing of the systems for the issuance of incandescent gases. In addition, this time "Object 604" was supposed to receive protection for all new components and assemblies.
The T-55 serial medium tank was to be used as the basis for the TMT vehicle. Special requirements for the new project led to the need for a serious rework of the existing equipment. First of all, OKB-174 employees changed the design of the armored corps. The tank was to be deprived of the turret and the upper part of the hull. Instead of them, the new project proposed the installation of a higher superstructure capable of accommodating all the necessary units. With this alteration, the appearance of the car was seriously changed.
"Object 604" received new frontal plates of a changed shape and a different thickness. Rolled armor plates 80 mm thick (top) and 60 mm (bottom) were placed at an angle of 55 ° to the vertical. The bottom sheet was distinguished by an increased width and cutouts for mounting trawling system aggregates. The upper one was noticeably narrower and served as the front wall of the habitable compartment. The sides with a thickness of 45 mm were connected to the frontal part. The main part of the superstructure occupied about half of the total length of the hull. Behind her, the hull height was reduced to its original values.
The most serious changes were made to the layout of the armored vehicle. The front compartment was now given over to accommodate the control compartment. The side and stern walls of the habitable volume were made of armored steel and equipped with thermal insulation. Large tanks for transporting aviation fuel were located under the control compartment and behind it. Two containers with a total volume of 1500 liters were used. In addition, next to them were fuel tanks intended for a tank engine. The aft compartment of the hull still housed the engine compartment.
It was proposed to place special equipment on the sides of the manned cabin. On each side, it was planned to install special polygonal armored casings required for the installation of turbojet engines. The casings consisted of sheets with a thickness of 20 to 60 mm. For some reason, the side casings were divided into two parts. The feed units of the casings were distinguished by an inclined rear cut, covered with a protective mesh. There was a small empty space between the engines and their protection.
The experimental machine is trawling
As a modification of the serial medium tank, the turbojet mine-sweeper was supposed to use the same power plant. The aft compartment of the hull housed a V-54 diesel engine with a power of 520 hp. With the help of a mechanical transmission, the engine torque was transmitted to the drive wheels of the aft position. Due to the relocation of the driver's control station, the transmission controls had to be modified.
The chassis of the "Object 604" was based on existing products, but had some characteristic features. Each side housed five large-diameter road wheels with individual torsion bar suspension. Due to the change in the loads on the chassis, the position of the rollers has been adjusted. Now the extended interval was present in front of the fifth roller, and not before the second, like in the base tank. In the front of the hull there were sloths with tensioning mechanisms, in the stern there were drive wheels.
Under large side casings, the minesweeper was supposed to carry two R11F-300 turbojet engines. This product was created in the mid-fifties to equip the latest MiG-21 fighter. Subsequently, the engines of this family were installed on some other domestic and foreign aircraft. The engine had a length of 4.61 m and a maximum diameter of 825 mm. The dry weight of the product is 1120 kg. The maximum thrust of the engine reached 3880 kgf, when using the afterburner - 6120 kgf.
The aircraft engine was proposed to be mounted on the side of the manned cabin "back to front". Its compressor was supposed to be inside the rear side casing, while the front one contained the combustion chamber, turbine and afterburner. This way of installing the engine has led to the need for thermal insulation in the control compartment. A nozzle device of an original design was mated with the standard engine nozzle. Coming out of the engine, the gases fell into a tunnel-pipe close to a rectangular cross-section. Such a pipe emerged from the bottom of the casing and laid on the fenders. Above the wing of the caterpillar, the pipe bent, and its front cut was above the ground.
To ensure the operation of jet engines, the TMT machine had on board two tanks for 1500 liters of aviation fuel. In the same compartment with them were tanks for diesel fuel consumed by the main engine. Due to the existing risks on the battlefield, it was decided to equip the armored vehicle with two fire extinguishing systems at once. The first was borrowed from the T-55 tank and was responsible for the safety of the engine compartment. The second task was to combat fires in the fuel compartment. Interestingly, in the development of this system, the components of aviation fire extinguishing equipment were most actively used.
Full-fledged prototype of TMT
The turbojet minesweeper Object 604 was to be operated by a crew of two: a driver-mechanic and an operator-commander. The crew was in the manned cabin of the hull. The driver's seat was at the left side of the compartment, the commander's seat was at the right. Both crew members had their own hatches in the roof of the hull. Observation devices were mounted on the hatches. The commander's hatch, in addition, was equipped with a searchlight. When trawling, practically excluding observation of the terrain, the driver had to maintain a given direction using the GPK-48 gyrocompass. The crew had two radio stations at their disposal.
A promising engineering vehicle was not supposed to carry its own weapon. At the same time, the crew had some means of self-defense. In case of engaging in battle, it was proposed to store two AK assault rifles with several magazines, 12 hand grenades and a signal pistol with ammunition in the stowage of the habitable compartment.
A device for marking the passage was placed in the aft part of the hull. While the car was moving through the minefield, it had to drop pyrotechnic signs on the ground. By observing the fire and smoke from the dropped products, the advancing troops could determine the direction of movement and the safe zone, cleared of explosive devices.
Despite a significant change in the design of the hull, the abandonment of the tower and the installation of new units, the minesweeper in its dimensions should not have significantly differed from the T-55 tank. At the same time, however, it was noticeably longer due to the front nozzle devices and the aft parts of the engine casings. The combat weight of the vehicle was determined at the level of 37 tons. Some reduction in specific power should not have a negative effect on mobility. "Object 604" could reach speeds of up to 45-50 km / h on the highway; on rough terrain, the speed was halved. The fuel range did not exceed 190 km.
By the middle of 1963, OKB-174 completed the creation of a new project, after which the construction of an experienced minesweeper began. This car was sent for testing in the fourth quarter of the same year. Soon the driving performance of the turbojet minesweeper was tested, after which the tests of new special equipment began. Sea trials showed that the mobility of the engineering armored vehicle remained at the level of the basic medium tank. In all conditions, she could work in the same battle formations with other armored vehicles.
View to the port side, noticeable improvements to the chassis
The principle of trawling with the new equipment was quite simple. Approaching the minefield, the crew had to establish a "combat course", turn on the turbojet engines, and also put the marking equipment into working condition. After that, it was possible to advance into the minefield and make a passage.
Two engines created thrust up to 6120 kgf each. The flow of reactive gases with the help of nozzle devices was directed to the ground with mines installed in it. The speed and volume of the gas flow had the most serious impact on the ground in front of the minesweeper. The gases literally ripped apart and blew away the topsoil. When working on soddy soils, a trench up to 500 mm deep was made. Trawling in the snow made it possible to deepen by 600 mm. Two nozzle devices mounted on the sides of the hull were developed and removed to the sides the soil in an area not less than 4 m wide. Under the influence of reactive gases, soil particles were scattered forward and to the sides. Together with them, the stream removed from the ground and threw out mines of any type. When making a passage in a minefield, "Object 604" had to move at a speed of about 3-4 km / h.
Obviously, after successful tests of the prototype TMT / "Object 604", which confirmed the viability of the original principle of trawling, it was decided to develop another similar machine. This time, OKB-174 specialists created a turbojet mine-sweeper based on the ISU-152K self-propelled artillery mount. The vehicle with the working designation "Object 606" received an updated body with a reduced thickness of the frontal armor. On the sides of the manned cabin there were engines and other special equipment borrowed from the Object 604 project. The new version of the minesweeper weighed 47 tons and, in terms of its mobility characteristics, hardly differed from the base ACS.
There is no information about the construction and testing of the Object 606 minesweeper. It cannot be ruled out that this project remained on paper, not even reaching the stage of construction of a prototype.
The prototype of the turbojet minesweeper TMT / Object 604 was tested and proved its capabilities, confirming the ability to make large passages in any mine-explosive obstacles. However, the car was not recommended for adoption. Apparently, the main reason for the refusal of the military from an interesting model was not the best economic indicators. With all its advantages, the original minesweeper had limited combat characteristics, and in addition, it turned out to be quite expensive to operate.
Engineering vehicle in the process of trawling
The main problems of TMT were associated with the chosen method of trawling. On board the vehicle were two R11F-300 turbojet engines, each of which had a specific fuel consumption of 0.94 kg / kgf ∙ h in cruise mode and 2.35 kg / kgf ∙ h in afterburner. Thus, for an hour of operation in cruising mode, each engine had to consume more than 3.6 tons of fuel. When switching to afterburner, the hourly fuel consumption exceeded 15 tons for each of the two engines. Nevertheless, about 1150 kg of kerosene could be poured into two fuel tanks with a total capacity of 1500 liters.
It is not difficult to calculate that the available stock of aviation fuel would be sufficient for a trawling for about 10 minutes with the cruising operation of the engines, and the inclusion of the afterburner would reduce this period several times. Thus, even with fuel economy, "Object 604" could make a passage no more than 600-700 m long at one gas station, after which it needed to be refueled. It is unlikely that an armored vehicle with such capabilities could provide a full-fledged offensive by troops in a dangerous area.
The problem of insufficient "cruising range" during trawling could be solved in two ways: using a more economical engine or increasing the capacity of the kerosene tanks. Apparently, there were no opportunities to use other aircraft engines. The increase in the fuel supply, in turn, was associated with the need for a serious re-arrangement of the internal volumes of the hull. Thus, there was simply no real opportunity to improve the characteristics of the "Object 604" to acceptable values.
Insufficient performance and the impossibility of increasing them led to a natural result. No later than 1964-65, the TMT / Object 604 project was closed. The same fate befell a similar development based on the ISU-152K self-propelled gun. The use of a different chassis did not in any way affect the basic characteristics of the vehicle, and it was impossible to correct the main shortcomings. After the project was closed, the built prototypes of the turbojet minesweeper were dismantled as unnecessary. This technique could be used in certain new projects as experimental machines.
An interesting engineering vehicle could not show the required characteristics and therefore did not enter service. In addition, she demonstrated that with the current level of technology development, turbojet minesweepers cannot find practical use. The original idea was abandoned and not returned to it for the next several decades. The unusual method of trawling was remembered only during the war in Afghanistan. Then, on the basis of serial equipment and using common components, the so-called. gas-dynamic minesweeper "Progrev-T". However, this car did not succeed in becoming a mass one.
