Obviously, the troops must be able to operate at any time of the day. Nevertheless, until a certain time, until the appearance of the appropriate technical means, the work of the army in the absence of natural light was associated with certain difficulties. Later, high-power lighting and night vision devices appeared. One of the most interesting domestic means of ensuring the work of troops at night was the Object 117 self-propelled searchlight installation.
By the end of the fifties, the first mass night vision devices were spread in our country and abroad. These devices belonged to the so-called. active class and therefore needed infrared illumination. In general, solving the assigned tasks, such equipment had some negative features. The fact is that the enemy, with his own night vision equipment, could easily detect the included illumination spotlights. Thus, early generations of night vision devices made it possible to see the terrain, but at the same time they unmasked their carrier with understandable risks and consequences. In the future, we managed to get rid of this problem, but before that, several interesting ideas had appeared.
In the late fifties, Soviet specialists proposed a new option for ensuring the work of troops in the dark. In accordance with this proposal, tanks and other armored vehicles during movement and fighting should not have used their own infrared searchlights. The terrain illumination they needed was to be carried out using a separate powerful searchlight mounted on a self-propelled chassis. The high power of such a searchlight could also be used to suppress enemy optical means.
"Object 117" in the museum
Even before the start of the design work, two options for using the searchlight installation were proposed and studied. The first meant direct illumination of the area in front of a self-propelled vehicle. This technique was relatively simple, but it was associated with increased risks, since an openly located armored vehicle could become a priority target for enemy artillery or aviation. The second technique proposed illuminating enemy positions with reflected light. At the same time, it was proposed to direct the searchlight to the clouds, which were supposed to work as reflectors. This allowed the self-propelled installation to solve problems, being behind natural shelters and without risking anything.
In 1959, the defense industry received a new assignment. She was required to create a promising self-propelled searchlight installation. The development of a new project was entrusted to OKB-3 "Uralmashzavod" (Sverdlovsk) and plant No. 686 of the Council of National Economy of the Moscow City Economic Region. As follows from the available data, Sverdlovsk engineers were responsible for the chassis and some on-board systems, and plant # 686 was supposed to create all the special electrical equipment of the machine. The project received the working designation "Object 117".
In order to simplify and accelerate the development of the project, it was decided to use the existing tracked chassis as the basis for the new self-propelled gun. Back in the late forties, Sverdlovsk engineers were creating promising self-propelled guns based on a unified chassis. Such a tracked vehicle was distinguished by some original features and could show high performance, but the process of its fine-tuning was noticeably delayed. One or another work to improve the existing sample, including those necessary to improve the main characteristics, continued until the very end of the fifties.
In the "Object 117" project, it was planned to use the basic version of the unified chassis, which was originally created as part of the "Object 105" / SU-100P self-propelled artillery mount project. For use in the new project, the chassis had to undergo minimal changes. All equipment associated with the artillery unit should have been removed from it. In addition, the installation of several new electrical and auxiliary devices of one purpose or another was required. First of all, it was necessary to equip the car with a searchlight installation.
The proposed appearance of the self-propelled searchlight installation made it possible to do without major reworking of the main chassis elements. So, it was proposed to use a slightly modified case. As before, it had to be assembled from armor plates no more than 18 mm thick and have the most powerful protection in the frontal projection. Other parts were made of armor with a thickness of 8 mm. All main sheets were joined by welding. The layout of the hull, in general, has not changed, but some of the existing volumes have changed their purpose. The front hull compartment still housed the transmission, while behind it was the control compartment and engine volume. All other volumes were required for the installation of special equipment.
The front of the hull consisted of several inclined armor plates, the upper one of which served as a transmission cover and could be lifted to service it. Behind him there was an inclined part that covered the engine compartment and the control compartment. The chassis had vertical sides, the central and stern parts of which formed small fenders. In the original configuration, the rear of the sides was made in the form of folding flaps. The searchlight self-propelled gun received rigidly fixed sides along the entire length of the hull. The stern leaf was placed vertically. Behind the engine, on the port side, there was a large open volume intended for a searchlight installation. To the left of it was a narrow section of the roof. A box-shaped casing was located behind the searchlight.
From the basic artillery self-propelled gun "Object 117" received a diesel engine V-105 with a capacity of 400 hp. In the front of the body and in front of the engine, there were the main dry friction clutch, a two-flow gear and swing mechanism, two single-stage final drives. As part of the SU-100P project, a highly efficient compact liquid cooling system and a small-sized transmission were previously developed. Some changes had to be made to the design of the power plant. So, an additional power take-off shaft was added, connected to a separate electric generator. A special generator of the PG-22/115 type with a power of 22 kW was intended for the power supply of the searchlight installation.
The searchlight and auxiliary systems were comparable in weight to the artillery mount of the basic SU-100P, which made it possible to use the existing chassis. Each side of the hull had space for the installation of six torsion bars with balancers, on which double rubberized road wheels were placed. The front and rear pairs of rollers were equipped with additional hydraulic shock absorbers. Three pairs of supporting rollers were placed above the rollers. The driving wheels were installed in the front of the hull, the guides were in the stern.
Behind the engine compartment in the body there was an open volume for a TP-15-1 type floodlight installation. There was a rotary device with a U-shaped support. Mechanical drives of the installation, controlled from the operator's console, provided circular guidance of the searchlight horizontally. Mechanized drives were duplicated by manual ones. Also, the searchlight in operating mode could swing from -15 ° to + 90 ° in the vertical plane. From the available data, it follows that when transferred to the transport position, the searchlight turned down by 90 °, however, after increasing the angle of descent to more than 15 °, it could no longer be effectively used for its intended purpose. There is reason to believe that the support of the searchlight installation had a bulletproof booking.
Self-propelled floodlight unit under test
The cylindrical body of the searchlight was fixed on the U-shaped support using a vertical aiming mechanism. The lamp and other devices were protected from external influences by a cylindrical body and a bottom curved outward. Almost the entire front end, with the exception of a small edge around the perimeter, was covered with glass. The characteristics of the light source used led to the need for cooling means. Warm air was removed through special pipes on the body.
As part of the TP-15-1 searchlight, an arc lamp and an incandescent lamp were used. The electric arc was distinguished by a high arc intensity: a current of 150 A was applied to its electrodes. Behind the lamp, in the rear part of the body, there was a paraboloid reflector with a diameter of 1.5 m. Such a searchlight had very high characteristics. The axial luminous intensity was provided at the level of 700 mega-candels. Also included in the spotlight was a high power incandescent lamp. The searchlight received a controllable light filter required to change the operating mode. Depending on the task at hand, the illuminator could work in the visible range or use an additional infrared filter.
The "combat" characteristics of the self-propelled artillery unit depended on the operating mode and the lamp used. An arc lamp without a light filter could with sufficient efficiency illuminate a strip of terrain 600 m wide at a distance of 3500 m. The use of an incandescent lamp reduced the effective range to 2800 m, and the strip width to 300 m. When using infrared filters, the Object 117 could ensure the operation of existing tank sights at distances up to 800 m.
A crew of three was supposed to drive a promising machine of an unusual type. The driver was placed in his regular place in the front of the hull, at the left side. Above it there was a private hatch with a pair of periscopic instruments. Behind it were the places of the commander and operator of the searchlight installation. These crew members had their own hatches, and in their workplaces there were the necessary control devices. While moving and working on the battlefield, the crew could remain under the protection of bulletproof armor.
The Object 117 self-propelled searchlight installation did not differ much from the basic ACS in terms of its dimensions. The maximum length reached 6.5 m, width - 3.1 m. Due to the searchlight on the support, the total height of the vehicle could reach 3 m. Combat weight - 20 tons. Specific power at the level of 20 hp. per ton, it allowed to reach speeds of up to 60-65 km / h and cover up to 300 km of track at one refueling. The mobility of the chassis, in theory, allowed the searchlight installation to work in the same battle formations with tanks and other armored vehicles.
The development of the Object 117 project continued until 1961. Until the end of 1961, two prototypes were built by the efforts of the development enterprises, which were to take part in the tests. Inspections of two cars started at the end of the same year and took several months. In the course of field tests, carried out with the participation of representatives of the Ministry of Defense, it was found that, in its current form, the presented equipment has a number of serious shortcomings.
Despite the long work on fine-tuning and improving the chassis, the self-propelled searchlight installation still could not show acceptable mobility characteristics. As a result, the self-propelled gun could not accompany the tank units on the march. It was also found that the mountings of the floodlight were not strong enough. As a result, while driving, the searchlight installation was exposed to increased risks, and in order to avoid negative consequences, it was necessary to limit the speed of movement, which could further reduce the practical effect of operating new equipment.
The TP-15-1 floodlight showed high technical characteristics, but its operational parameters were criticized. The high illumination range was obtained at the cost of the rapid burnout of the arc lamp electrodes. The result was an unacceptable reduction in the continuous operation time of the floodlight, and in addition, the operator of the floodlight had to leave the protected volume to replace the electrodes.
Also, during the tests, it was found that the axis of the searchlight is at an insufficient height. When using a spotlight on "direct fire", relatively tall objects left behind them long, clear shadows. The presence of the latter significantly hampered the orientation on the terrain, distorted the landscape and interfered with normal observation. Thus, in the existing configuration, "Object 117" could not perform the assigned tasks correctly.
Searchlight installation moved to stowed position
According to some reports, some unusual results were obtained during the tests, which quickly became part of folklore. For example, a powerful arc lamp of a searchlight easily burned grass within a radius of several meters. There is also a known bike, according to which it was possible to cook food with the help of a TP-15-1 searchlight: it took no more than 15-20 minutes to fry a chicken placed next to the glass.
The not very successful design of the floodlight installation and the chassis, which still had certain problems, led to the completion of the tests with a negative result. In its current form, "Object 117" could not accompany troops or highlight enemy positions for the required time. A special armored vehicle with such characteristics and capabilities was not of interest to the army, and therefore it was decided to abandon the project. The self-propelled searchlight installation was not accepted for service and was not recommended for mass production. Further development of the project was also considered unnecessary and meaningless.
Later, one of the experimental "Objects 117" was transferred to the Kubinka Armored Museum, where it is located to this day. The exact fate of the second car is unknown. Apparently, the no longer needed prototype was disassembled and sent to be smelted.
By the end of the fifties, the domestic defense industry managed to launch the production of night vision devices of several types, which found application in the troops and increased their combat potential. However, the performance of existing systems was still inadequate. The main solution to this problem was the further development of technologies and equipment. In addition, it was proposed to create a special machine capable of helping other equipment with only active night vision devices.
The Object 117 project led to the construction of two prototypes, but never progressed beyond their testing. In the proposed form, a promising armored vehicle had a lot of technical and operational shortcomings. Getting rid of them required significant processing of certain structural elements or was impossible due to limitations in the field of technology. As a result, further development and improvement of the project was considered inappropriate. However, it should be noted that already at the beginning of the sixties, the need for separate searchlight installations disappeared. By this time, new results were obtained in the field of night vision devices, and soon the first such systems of the passive type entered service, which no longer needed special sources of infrared radiation. Thanks to this, the army no longer needed separate lighting means, including those based on self-propelled chassis.
