Loitering ammunition for APU ST-35 Silent Thunder
ST-35 loitering ammunition in launch configuration. Photo Factmil.com
In recent years, the Ukrainian army and military industry have focused on the development of unmanned aviation and related technologies. Attempts have been made to develop various systems of this class with certain features. For example, several years ago the ST-35 loitering ammunition began to be demonstrated at exhibitions. It was developed using foreign ideas and unusual but interesting solutions.
Exhibit for exhibitions
The ST-35 loitering munition (AM), also called “Grim”, Silent Thunder and “Silent Thunder”, was developed on its own initiative by the Ukrainian company Atlon-Avia. This project was first talked about in 2019, and by this time the development company had managed to complete some of the necessary work and produce a model of the equipment for demonstration at the exhibition. Subsequently, the ST-35 was repeatedly shown at Ukrainian and foreign events.
In 2019-20 The new type of BB has passed factory tests. Allegedly, it confirmed the calculated characteristics and met expectations. In particular, the unusual way of starting and ensuring work proved to be good. The ability to fly under operator control and along a predetermined route, as well as a number of other modes and functions, was demonstrated.
In parallel with the testing of BB / UAVs, the process of developing auxiliary ground assets was underway. Thus, in 2020, they showed the concept of a self-propelled vehicle carrying loitering ammunition. Due to the specific launch method, it was possible to do without complex units and structures. However, as far as we know, such ideas have not reached the point of being implemented “in metal” or used at least on a test site.
During the exhibitions, the ST-35 product attracted attention and received high marks from Ukrainian experts and commentators. It was expected that it would be of interest to the military department, go into production and enter service. However, apparently this did not happen.
Pairing the BB and hexacopter. Photo: Defense-ua.com
Reliable information about the availability of orders for the Grim BB and the appearance of such products at the disposal of Ukrainian armed forces has not yet been received. There is also no data on the use of these products in the combat zone. However, it cannot be ruled out that the production of such UAVs was carried out, but in small volumes, due to which they did not leave a noticeable trace.
Unmanned complex
From a technical point of view, the ST-35 Silent Thunder is an unmanned aircraft system for reconnaissance and strike purposes. Its main element is a UAV with optics and a warhead, capable of reaching a given area, finding a target and hitting it with a direct hit. In this respect, the ST-35 is no different from other modern BBs. At the same time, this complex uses an interesting idea aimed at increasing some operational and combat characteristics.
The “Silent Thunder” complex has an unusual composition. It includes the BB itself with a characteristic appearance, a hexacopter with a launcher function, a support device, control panels, containers for transportation, etc. In the portable version, the complex is divided into three backpacks weighing approx. 15 kg for transportation by calculation or transportation by any transport. The self-propelled version of the complex can transport a large number of warheads and several auxiliary UAVs.
The ST-35 loitering ammunition is similar in appearance and design to the Hero products of the Israeli company UVision and to the Russian Lancet. Apparently, they were the "source of inspiration" during development. The device has an elongated fuselage of small cross-section, to which two sets of X-shaped planes are attached - a pair of wings and a pair of stabilizers. The UAV is transported disassembled and assembled immediately before launch. Inside the fuselage, an optical-electronic station, communication control equipment, a warhead and a propulsion system with batteries are successively placed.
The on-board systems of the UAV provide flight according to operator commands or independent execution of the programmed program. The use of inertial navigation has been reported to reduce vulnerability to electronic warfare. While in flight, the ST-35 communicates with the operator's console and transmits a video signal from the nose camera and other information to it.
BB optical means. Photo: Defense-ua.com
The propulsion system is completely electric. With the help of an electric motor with a pushing propeller, the BB reaches a speed of no more than 120-130 km/h. Battery charging lasts for 60 minutes. flight. Range of action – up to 30-40 km. The UAV spends approx. 15 minutes, after which it can patrol and search for a target.
With a take-off weight of up to 10 kg, the ST-35 carries a warhead weighing 3,5 kg. The development company mentioned the possibility of installing a high-explosive fragmentation, thermobaric or shaped charge.
The complex also includes a hexacopter drone. Its characteristic feature is a body with a round hole in the middle and mechanisms for docking with the BB. On board the copter there are control devices and a radio signal repeater.
Principle of operation
The developers of ST-35 proposed an interesting version of the launch system, which allows you to launch a UAV from a place and without searching for a large site. Thus, when the complex is deployed, a launch support of the simplest design is placed at the position or inside the carrier vehicle. Loitering ammunition is placed vertically on it. The hexacopter is literally placed on its nose and the locks are activated. In this form, the complex is ready for use.
At the operator’s command, the hexacopter rises into the air along with the BB. At an altitude of 500 m, it is proposed to drop the ammunition, after which it should stabilize and go into horizontal controlled flight. After the reset, the BB is sent to the target area, and the copter rises to a height of approx. 1 km and hovers, providing relay of radio signals.
Layout of the self-propelled version of the ST-35. Graphics "Athlone-Avia"
Otherwise, the use of the ST-35 seems to be the same as in the case of other modern loitering ammunition. After hitting the target or missing, the carrier copter and repeater must return to the ground and ensure the takeoff of the next AP, until the battery runs out or the available ammunition is used up.
Advantages and disadvantages
It is easy to notice that the Ukrainian loitering ammunition ST-35 / Silent Thunder / “Grim” is as similar as possible to a number of other modern systems of this class and has similar characteristics. The only noticeable difference was the special launch system, which was supposed to give it some advantages.
In general, the idea of launching an aircraft-type BB using a special drone-helicopter is of interest. It eliminates the need for a bulky launch catapult and reduces the requirements for the launch position. In addition, the presence of a radio repeater on board the UAV should increase the reliability of communications and the complex as a whole.
However, replacing a catapult with a copter seriously complicates the complex and increases its cost. In addition, practice and extensive experience in the use of modern warheads show that a launcher in the form of a long beam, despite all its shortcomings, generally does not complicate the operation of equipment.
The ST-35 has flight performance and combat capabilities at the level of some other modern UAVs, and there is no need to talk about superiority over such equipment. At the same time, “Silent Thunder” received all the characteristic disadvantages of such UAVs, and some of them are more pronounced.
Demonstration of the complex to a potential customer. Photo "Athlone-Avia"
First of all, the weak point of the complex is the radio channels through which video signals and commands are transmitted. They can be detected and suppressed by electronic warfare systems, after which the effectiveness of the ST-35, at a minimum, will drop sharply. At the same time, in the Grom complex, radio communication is carried out through a repeater drone, which can increase vulnerability to interference.
There is no reason to believe that ST-35 ammunition is a difficult target for modern air defense systems. During the attack, he will have to enter the zone of destruction of anti-aircraft weapons, and a breakthrough to the target is not guaranteed. Only the hexacopter remains in relative safety, but by itself it will not solve the combat mission.
No real prospects
It seems that the ST-35 complex could not interest the Ukrainian command, and therefore did not enter service or was not produced in large series. Later, at the beginning of 2022, the Kiev regime wanted to obtain loitering ammunition, but it had to fill this niche at the expense of foreign models. However, foreign assistance on a significant scale did not help the Ukrainian formations.
Thus, the ST-35 project shows that combining proven solutions and new ideas does not always give the desired result. The basic concept must be accompanied by the required level of characteristics and production capacity. Otherwise, any project has no real prospects.
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