In 1932, Soviet industry developed and put into series the TDP-3 tank smoke device. This device could be installed on various platforms and solved the problem of contamination, degassing and setting smoke screens. Tanks of different models became the carriers of devices, incl. heavy T-35. However, in his case, it was not possible to do only with a serial product, which led to the start of a new interesting project.
Smoke device TDP-3 appeared almost simultaneously with the launch of serial production of T-35 tanks. As a result, all new machines received such equipment, which gave them new opportunities. With the help of the TDP-3 device, the tank could put a smoke screen, covering itself or friendly troops. At that time, it was believed that smoke exhaust equipment was necessary for most tanks of all classes.
For installation on the T-35, the smoke device had to be slightly modified in terms of the layout of the units. On the sides of the turret box of the tank there were two armored boxes, which housed two tanks from the TDP-3 – 40 liters each. Next to them were the means of creating pressure to eject the liquid.
The liquid from the tanks was supplied under pressure to the pipelines laid under the fenders. The tube passed through the trailing edge of the shelf and ended with a nozzle. The aerosol was ejected into the rear hemisphere.
Stern view. Small nozzles are visible on the edges of the fenders. Photo Military.wikireading.ru
To control the smoke outlet in the fighting compartment, hatches were provided to give access to the devices. Inside the tank, a simple console was placed in the form of a sector with a lever, similar to that used in other equipment projects with the TDP-3. The crew could turn on and off the device, as well as control the intensity of the launch.
Smoke screens were installed using S-IV special fluid. 80 liters of such a mixture provided a smoke outlet for 5-12 minutes. The launch was carried out both from a place and in motion, with one device or two. One tank could create a curtain hundreds of meters long and up to 25-30 m high. The use of toxic substances by T-35 tanks was not provided – in contrast to specialized chemical tanks with the same device.
Tank smoke device mod. 1932 was quickly adapted for use on the T-35 and was soon included in its standard equipment. TDP-3s were mounted on all serial heavy tanks, giving them the required capabilities. Thanks to such devices, the tank unit could independently cover itself and protect itself from observation or shelling.
The TDP-3 device met the original technical requirements, but was not devoid of shortcomings. One of the main complaints related to the relatively small capacity of the tanks, which limited the duration of the smoke outlet and the size of the resulting curtain. In addition, the tanks and pipelines were not heated – this excluded the installation of the curtain in the cold season.
TDP-3 device of open installation on a BT series tank. Photo from the book Kolomiets M.V. “Light tanks BT.” Flying tank “of the 1930s”
In 1936, all this led to the start of the development of a new tank smoke device specifically for the T-35. The new TDP-4 product was supposed to get rid of the shortcomings of its predecessor, and also more fully correspond to the specifics of the design of the heavy carrier tank. Due to the use of the TDP-4 device, the tank could turn into a full-fledged curtain producer, retaining all the basic combat qualities.
The TDP-4 device was developed by the Kompressor plant, the main creator of chemical equipment for the army. Various army units were involved in the work. An experienced T-35 tank with new equipment went for testing in the same 1936.
The main innovation of the project was the enlarged tanks for special fluids. Compressed gas cylinders were removed from the armored boxes near the turret platform, thereby freeing up space for tanks with a capacity of 90 liters. The compressed air cylinders were moved to the fighting compartment. They had a capacity of 5 liters and held a pressure of 150 kgf / cm 2. With the help of reducers, the pressure was reduced to 5 kgf / cm 2, after which the compressed gas entered the tanks with liquid.
Along the roof of the housings, as before, there were pipelines for supplying liquid to the nozzles. However, this time they were laid next to the exhaust manifolds of the engine, which ensured the heating of both the pipe and the liquid in it. This made it possible to use the smoke release devices at any time of the year and in all weather conditions. The design of the nozzles as a whole has not changed.
T-35 fires smoke. Photo from the book Solyankin A.G., Pavlov M.V., Pavlov I.V., Zheltov I.G. “Domestic armored vehicles. XX century”, Vol. 1
The increased capacity of the tanks gave obvious advantages. T-35 with TDP-4 could carry out the setting of the curtain for a longer time or with greater intensity. The maximum flow rate of S-IV liquid reached 15 l / min. The tank could install a dense and imperceptible curtain up to 25-30 m high and up to 1600 m long.
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In 1936, one of the serial T-35 tanks lost the standard TDP-3 device, instead of which a new TDP-4 was installed. In this configuration, it was tested at the test site and the strengths and weaknesses of the new development were determined. The test results turned out to be unambiguous, but did not lead to a massive re-equipment of equipment.
The TDP-4 compares favorably with its predecessor, and the re-equipped T-35 had clear advantages over the serial one. However, the new tank smoke device was not developed. Already built T-35 tanks retained the standard devices of the previous model, and they were also installed on new production vehicles. The reasons for this development of events are not entirely clear, but some assumptions can be made.
The Compressor plant has produced about 1500 TDP-3 devices in just a few years. Such products were enough to equip new tanks of several types, incl. heavy T-35. The loss of a serial device in terms of characteristics could be considered insignificant. Despite the limited smoke release time and a smaller curtain, the TDP-3 coped with the assigned tasks and provided proper camouflage.
Museum T-35 in Kubinka. Smoke appliances are removed, only windows for nozzles remind of them. Photo Wikimedia Commons
With all its advantages, TDP-4 had a characteristic drawback in the form of large dimensions and weight. In this respect, it was inferior to the previous TDP-3 – and therefore was not compatible with all existing tanks. Without prejudice to mobility, only medium and heavy armored vehicles could carry it, which should have led to de-uniformity.
The specific ratio of the strengths and weaknesses of the device, as well as the peculiarities of the use of such devices, led to a natural ending. TDP-4 was not accepted into service and put into series. The existing device of the previous model remained in the army. However, not all tanks had such equipment. Some of the machines did not receive the TDP-3 at all, while such equipment was removed from others during operation.
After the failure with the new device, the TDP-3 retained the place of the main model of its class in the Red Army. It was actively used on armored vehicles of various types until the early forties. Later, with the outbreak of World War II, tanks with such equipment provided cover for the troops and confirmed their capabilities. In practice, it has been shown that even a limited amount of special fluid can be sufficient to solve the assigned task and hide troops from the enemy.