Currently, preparations are underway for serial production of promising Su-57 fighters. As in the case of prototypes, the serial equipment will be equipped with engines of two models. The first production samples will receive the existing AL-41F1 engines (they are also "first stage engines"), and then newer "Products 30" will replace them in the series. Since the end of 2017 promising turbojet engines "Product 30" have been tested in the air, and in the future it is expected to master their production in the interests of serial production of aircraft.
TRDDF type "Product 30", or "second stage engine", is one of the main topics in the context of the PAK FA / T-50 / Su-57 project. Moreover, this topic is one of the most closed.
However, to date, the developer represented by NPO Saturn, as well as officials from the Ministry of Defense and other structures have managed to disclose some of the data and draw up a rough picture. It is expected that new information will continue to flow in the future, and the industry will reveal new details of an interesting project.
Fifth generation engine
The Su-57 fighter belongs to the conditional fifth generation, which indicates the presence of a number of characteristic requirements. One of the main such requirements is to ensure cruising supersonic speed, including without the use of afterburners. Existing serial engines do not allow such characteristics to be obtained, and therefore a completely new power plant is required. A promising engine designed for the Su-57, like the aircraft itself, is attributed to the conditional fifth generation - however, already in the field of engine building.
Su-57 aircraft with "first stage" engines - AL-41F1. Photo UAC / uacrussia.ru
It is believed that the difference between generations of turbojet engines is manifested in the change in basic parameters. A sharp increase in specific thrust or a reduction in specific fuel consumption achieved in the new project make it possible to refer it to the next generation. The newest TRDDF "Product 30" by these indicators compares favorably with the existing systems, which allows its developers to talk about creating an engine of the "5" or "5+" generation.
The high performance of the new engine is achieved primarily through the use of the most modern technologies, materials and solutions. In this case, ideas that have already been mastered are also used. Thus, "Product 30" continues the line of domestic engines with a standard nozzle with thrust vector controls.
However, some modern solutions had to be abandoned. For example, in 2013 NPO Saturn showed a promising design of a high-pressure compressor blade made of titanium aluminide. There have been reports of the possible introduction of such a material into the design of the turbine. However, later on, titanium aluminide in the composition of "Product 30" was abandoned. The weight savings turned out to be negligible, and the resistance to the increased mechanical and thermal loads typical of military engines was insufficient.
Technical details
According to known data, "Product 30" is a by-pass turbojet engine with an afterburner. At the level of some basic ideas, it resembles the older engines of the AL-31 and AL-41 families, but all of its units were developed anew and using modern developments. The result of this was a noticeable increase in all the main characteristics, allowing the "Product 30" to be attributed to the next generation of TRDDF.
The engine has a typical architecture for its class with multistage high and low pressure compressors, a combustion chamber and multistage turbines. Behind the turbines are the afterburner and the nozzle with the UHT. Necessary units for one purpose or another are placed on the outer surface of the engine. The developers of "Product 30" are in no hurry to disclose all the details of the design, but some of the features of the new project are already known.
The compressor provides compression of the incoming air with a degree of 6, 7, providing an air flow rate of up to 20-23 kg / s. The combustion chamber is equipped with a plasma ignition system installed directly on the injectors. Such means ensure that the fuel is ignited immediately after it enters the combustion chamber. Thanks to this, the optimal combustion mode is maintained, and the so-called. torch - improper combustion of fuel accumulated in the engine. The temperature of the gases in front of the turbine ranges from 1950 to 2100 ° K. For comparison, for a serial AL-31F engine, this parameter does not exceed 1700 ° K.
Experienced Su-57 with the "Product 30" engine. Photo Nickolay Krasnov / russianplanes.net
The "30" engine is equipped with a new nozzle with thrust vector control functions. This unit is noticeably smaller than those previously used and has different contours. In particular, the trailing edge of the nozzle, formed by the individual flaps, becomes uneven.
An important design feature that provides new opportunities is the change in the degree of bypass. The project also took into account the need to reduce the visibility of the engine and the aircraft as a whole for radar and infrared surveillance systems. Such problems were solved by creating optimal designs of the air intake and nozzle.
An original electronic digital control system with full responsibility has been created for the new engine. It receives data from many different sensors and monitors the operation of all engine components. Receiving commands from the pilot, the control system executes them taking into account the current parameters and various factors. Automatic engine control simplifies the work of the pilot, and also facilitates the tuning of the power plant for work in certain conditions.
All new ideas and solutions are intended to improve the basic characteristics of the engine. According to open data, the maximum thrust of the "Product 30" engine reaches 11000 kgf, afterburner - 18000 kgf. For comparison, the AL-41F1 first stage engine has a thrust of 9500 and 15000 kgf, respectively. Thus, the Su-57, even with a maximum take-off weight exceeding 35 tons, will have a thrust-to-weight ratio of more than one. With a normal takeoff weight, this parameter will reach 1, 15-1, 2.
The specific parameters of the new engine either improved or remained at the level of previous products. Thus, the management of NPO Saturn indicates that the specific fuel consumption of the Product 30 remained at the level of the AL-31F engine - about 0.67 kg • kgf / h. At the same time, the specific thrust increased, but the exact value of this parameter is not named. With such parameters, in terms of its dimensions and weight, the "30" engine hardly differs from the serial domestic turbojet engines.
Optimization of the main parameters leads to an increase in the aircraft performance characteristics. According to various estimates, the cruising supersonic speed of the Su-57 without afterburner, provided by two engines with a thrust of 11,000 kgf each, can reach M = 1, 5. The presence of a nozzle with UHT significantly improves maneuverability in all modes.
Plans for the future
So far, the promising product 30 turbojet engine remains at the stage of flight tests and is being tested on prototype T-50 / Su-57 aircraft. To date, about two dozen experimental engines have been manufactured for testing on the ground and in the air. Flight tests of the engines have been going on for over a year and will take more time. So, at the beginning of last year it was reported that the entire flight test cycle could take three years.
Engine "30" in the assembly shop (presumably). Photo Militaryrussia.ru
According to current plans, in the coming years, the Russian aerospace forces will receive several of the first production Su-57 fighters. The first vehicles of this type will be equipped with the so-called. engines of the first stage - TRDDF AL-41F1. In 2020, a second contract for the supply of serial equipment should appear. This time we are talking about the introduction of new engines. Part of the fighters of the second series will be equipped with "Products 30". The serial production of such engines will be mastered by the UEC-Ufa Engine-Building Production Association. In the future, approximately in the mid-twenties, the new engine will become standard for all serial Su-57s.
In parallel with testing and fine-tuning "Product 30" in its existing version, work is underway to create new units for such an engine. The development of a flat nozzle capable of reducing the aircraft's signature in different spectra is underway. Instead of the standard nozzle, it is planned to place a curved channel behind the engine, on which two movable flat flaps should be installed.
The S-shaped channel shields the turbine blades from radar radiation, and the rectangular section of the nozzle reduces infrared radiation from reactive gases. At the same time, such units create additional resistance to the movement of gases, which leads to a slight reduction in the technical characteristics of the engine. The new nozzle is still in its early stages, and it is not yet known whether it will be implemented in future upgrades of the Su-57. However, with the help of such a project, Russian engine builders are gaining important experience.
It is also reported about the elaboration of the issues of creating the "sixth generation" engine. To further improve the basic and specific characteristics, it is proposed to add a third circuit in addition to the two existing ones. However, such ideas still remain at the stages of the earliest research, and therefore they can hardly be considered in the context of further refinement of the Su-57 fighters.
So far, the main task of engine builders within the PAK FA program is to fine-tune "Product 30" with the subsequent launch of its production and introduction into serial production of Su-57 fighters. Apparently, the engine will go into production in its current configuration - with a number of special technical solutions that increase the overall performance. At the same time, cardinal overhauls, such as the installation of a new nozzle, are not yet planned.
The main result of the project under the working designation "30" is the creation of a high performance turbojet engine for the newest Russian fighter. At the same time, do not forget about other important points. After completing work on "Product 30" and bringing it to service in the army, the Russian engine building will once again show its potential and confirm its leading position.
