New S-71K and S-71M UAVs for the Russian Aerospace Forces: features and prospects

The carrier of the S-71 UAV is the 5th generation Su—57 fighter

The Russian industry is actively engaged in the development of munitions for front-line aviation and regularly offers the most interesting solutions. For example, recently it became known about a new line of strike items under the general designation S-71. They are positioned as air-launched unmanned aerial vehicles and at the same time have the characteristic features of cruise missiles.

On August 1, 2023, the United Aircraft Corporation (PAO “OAK”) filed a patent application for the registration of the invention “Air-Launched Unmanned Aerial Vehicle with a Warhead and Method of Its Use.” In March 2024, the organization received a patent numbered RU2816326C1.

The document described an original UAV capable of performing the functions of a loitering munition or a cruise missile. General features of its design, principles of operation, etc., were provided. Schemes of the intended combat use were also disclosed. Interestingly, the Su-57 fighter was depicted as the conditional carrier of the UAVs in the illustrations.

This patent attracted the attention of specialists and the public, but it did not cause a particular stir. The fact is that domestic defense organizations regularly patent various concepts and ideas, but not all of them reach full implementation.

Later, in the summer of 2024, a book by P. Plunsky titled “Sukhoi Experimental Design Bureau” was published, dedicated to the 85th anniversary of the organization. It describes the history of the leading OKB and its developments from the very beginning and up to the present day. Naturally, the modern history of the organization is of particular interest.

An entire paragraph of this book was devoted to the previously unknown UAV designated S-71. For the first time, information about this development, its history, goals, and achievements was provided. Moreover, for the first time, images of experimental UAVs taken during tests were published.

Unlike the patent, the information from the book attracted attention both in our country and abroad. Various assessments and attempts at analysis based on available data began. In addition, information from unofficial sources emerged, supplementing the overall picture but raising questions.

According to open publications, in 2019, the Sukhoi company began working on the design of a promising UAV with strike and other functions. To simplify operation and application, it was proposed to execute it in the form-factor of a cruise missile and use it on front-line aviation aircraft, including the latest Su-57 fighter.

The future UAV was named a “guided low-observable weapon module.” It was also assigned the working designation S-71. Over the first few years, an optimal design was formed, the composition of aggregates was determined, and other tasks were resolved. In 2022, work on the S-71 project accelerated—the developing organization wanted to complete the design more quickly and bring the UAV into service.

In 2023–2024, the project successfully reached flight tests. For example, last year, a series of test flights were conducted, with the Su-57 fighter serving as the UAV carrier. This aircraft is also present in the published photographs of the UAVs.

No new information about the progress of the S-71 project has been received so far. How it has developed over the past year and what achievements have been made is still unknown. Considering the results of previous work, it can be expected that in the coming months, the new UAV will reach experimental operation in the troops and combat use. Moreover, it may be adopted by the Aerospace Forces.

According to published data, within the framework of the S-71 project, an unmanned aerial platform was developed, and two aircraft were created based on it. These UAVs have a maximally similar design but differ in equipment composition, functions, and capabilities.

One of the aircraft received the designation S-71K and the name “Kovyr.” It is intended for striking remote ground or surface targets with pre-known coordinates. In essence, it is a direct analogue of a traditional air-launched cruise missile.

The second UAV is designated as S-71M and carries the code name “Monokhrom.” This is an air-launched loitering munition capable of autonomous operation. It is designed to patrol a given area on its own, search for and recognize targets. Then the UAV independently makes a decision on conducting an attack and homes in on the selected object.

Both new UAVs have a common glider and are built according to a normal aerodynamic scheme. The design is formed with the consideration of reducing detectability and minimizing dimensions in the transport position. The exact sizes and weight of the items are unknown, but it seems that they do not differ from a number of existing cruise missiles.

It should be noted that an experimental prototype of a different design is present in the photo materials. Judging by its appearance and color, it was an experimental mock-up for early tests. The design of the UAV was changed later.

The S-71 has an elongated fuselage with a pointed nose and a hexagonal cross-section of the main part. Folding wings are installed on the sides. The tail unit is folding, V-shaped. The UAV is suspended on the carrier upside down, with the necessary attachments provided for this purpose. In addition, there is a hatch in the nose part, through which access to the connectors of the device is provided.

“Kovyr” and “Monokhrom” are equipped with a turbojet engine TRDD-50 or a similar type. With its help, the UAV develops a high subsonic speed. The range and duration of the flight are unknown. However, it is clear that the performance characteristics are sufficient for loitering in the target area.

The air-launched cruise missile UAV S-71K should have a simple control system that ensures flight to the given coordinates. For the S-71M, a more complex set of devices and instruments should have been developed. Such a UAV needs observation means, optical or radar, a computer for data analysis, an autopilot, etc. A radio station is also needed for communication with the carrier aircraft to transmit data on the target and to obtain permission to attack. The exact composition of the electronics of the new UAV and the principles of its operation are still unknown.

Both S-71 items are aviation strike means, but information about their combat capabilities is missing. According to some data, the “Kovyr” item could be equipped with a cassette warhead, while the “Monokhrom” should carry a monoblock fragmentation-high-explosive one. Whether these assessments are correct is unknown.

In the published materials, only one carrier of the S-71 UAV is shown—the fifth-generation fighter Su-57. The UAVs are suspended using a beam holder of one of the latest models. Whether the new UAVs are compatible with other domestic aircraft is unknown.

Thus, one of the leading aircraft manufacturing organizations in Russia has decided to use its experience to create aviation strike means. The result of this was the emergence of two strike UAVs, similar to cruise missiles and capable of solving different tasks related to the destruction of ground targets.

Last year, both variants of the S-71 UAV passed tests and confirmed the calculated characteristics. Likely, the development of the two projects continued after that and new successes were achieved. The current state of this program is unknown, but there are reasons for the most optimistic assessments and forecasts.