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In what directions is the Russian aviation engine industry developing? Editor-in-chief of "AN" Andrey Uglanov speaks about this issue with Evgeny Shakhmatov, Academician of the Russian Academy of Sciences, Doctor of Technical Sciences, scientific director of Samara National Research University.
- Dear Evgeny Vladimirovich! Over the past 10 years, thanks, among other things, to my newspaper Argumenty Nedeli, our citizens have learned a lot about aircraft and rocket engines. Even today, the newspaper does not miss a single issue, so as not to touch on this topic. Therefore, God himself ordered me to meet with you – the leading engine engineer in the world – so writes both our and foreign press. And your Samara National Research University, where you have been rector for a long time, and today you are a research supervisor, is called one of the top ten technical universities in the world. Therefore, we take the bull by the horns. How did it happen that the world's best rocket and aircraft engines were designed and launched in Samara and the region? The For instance, RD-107, RD-108, NK-33, NK-93, and others. What kind of place is this – where the propellers spin faster than in other places, and the jet stream is the most constant and powerful?
– In Samarskaya Luka, where the Volga makes a big turn around the Zhiguli Mountains, there is an anomaly that gives strength not only to local residents, but also to the whole of Russia. This lyrical digression brings us to the topic of engines. First of all, I want to emphasize that I am not the main specialist in the field of engine building; there are outstanding professionals who should be looked up to.
If we talk about engines, it is worth mentioning RD-107 and RD-108. These engines were used on the R-7 rocket, now known as the Soyuz. It was Sergei Pavlovich Korolev who transferred the production technologies of the first two stages of this rocket to Samara, and Valentin Petrovich Glushko was engaged in the development of engines, which then went into mass production. Thanks to Korolev's efforts, the era of rocket engineering, satellite engineering and remote sensing of the Earth began in Samara, which was continued by Dmitry Ilyich Kozlov, the famous designer of rocket and space technology, general designer of Rocket and Space Centre "Progress".
Another brilliant designer of aircraft and rocket engines is Nikolai Dmitrievich Kuznetsov. He was the man who took on any difficult task in the name of the Motherland. He gathered a unique team that allowed him to create engines such as the NK-93. But it is worth remembering about other models: NK-4, NK-6, NK-8 – the last of which was used on the Tu-154, and NK-144 – the engine of the first supersonic passenger aircraft.
The NK-32, NK-25 and NK-12 engines are the main ones for strategic aviation. Special attention should be paid to the NK-12, a unique turboprop engine that remains unsurpassed in the world to this day. All these achievements are the result of the work of Nikolai Dmitrievich Kuznetsov and his design bureau, as well as many enterprises, universities and scientific organizations that supported this complex.
Speaking of other engines, it is impossible not to recall Genrikh Vasilyevich Novozhilov, who, unfortunately, has already left us. At the University in Samara, he was shown the Aircraft Engine History Center, where he saw the NK-56 engine. This engine, which you do not mention, is unique, as it was intended for the IL-96 aircraft, which later became known as the IL-96-300.
Geinrikh Vasilyevich told the story that it was originally planned to install the NK-56 on the Il-96, which was supposed to accommodate about 350 passengers. However (now we can talk about it openly), the Minister of Aviation Industry, I.S. Silaev, invited him and informed him that the NK-56 would not be used on this aircraft; instead, there would be another engine, the PS–90. Despite all the efforts of Genrikh Vasilyevich to continue working with NK-56, it was not possible to overcome the administrative resource.
After this conversation, Gennrikh Vasilyevich returned to the design bureau and gathered his deputies, announcing to them that they would not develop the Il-96, but the Il-96-300. Everyone was surprised: usually the modifications were indicated by the letters M, B or A, but here – 300. Why? Because part of the fuselage was cut out, and as a result, 50 passengers "disappeared" – now, instead of 350 people, the plane could accommodate only 300.
Do not forget about other Kuznetsov engines, which were subsequently used for gas pumping and for small power plants. It was a conversion made thanks to the efforts of Nikolai Dmitrievich Kuznetsov. There were amazing people behind him who did things that others couldn't do.
How our lunar program "turned out"
– I remember a lot of conversations about the unsuccessful lunar program in the USSR. About the N-1 rocket project. It was never implemented, but the unique NK-33 engines remained from it. What is this story?
– The history of the NK-33 engine began at the moment when Sergei Pavlovich Korolev conceived the lunar rocket of the N-1 project. We are now talking about it as a super rocket, unique in its kind, but then the designers faced purely technical tasks. Korolev turned to Valentin Petrovich Glushko with a request to develop a more efficient liquid rocket engine (LRE) of a closed circuit. However, Glushko replied that the time had not yet come for such an engine.
Upset, Korolev met with Andrey Nikolaevich Tupolev and shared his problems. Tupolev suggested that he turn to Nikolai Dmitrievich Kuznetsov, an aviation designer from Kuibyshev, who was famous for his progressiveness and willingness to take on difficult tasks. Korolev actually went to Kuibyshev and convinced Kuznetsov to start creating a liquid rocket engine. Nikolai Dmitrievich gathered his young colleagues and, without mentioning Glushko's skepticism, said: "Guys, we need to make such an engine." As a result, the NK-33 appeared.
In the 90s, the company lived by selling this engine to the Americans. This story demonstrates Nikolai Dmitrievich's foresight and his ability to inspire his colleagues to great things. Among them were graduates of the Kuibyshev Aviation Institute, which underlines the uniqueness of this story.
– When did the "aircraft engine" specialization of the Kuibyshev and then Samara regions begin to take shape?
– Are you wondering why Kuibyshev and Samara are focused on aviation topics? The answer lies in the origins of the creation of these enterprises, which were evacuated here during the war. We started from scratch, installing machines in the open air, and people worked in such conditions. Later, buildings appeared and barracks were built where workers lived.
Working conditions can be called Spartan by modern standards, but people knew what they were working for: so that the Motherland would get what was required of them. This hardening has remained until now. Therefore, a unique history of enterprises related to aerospace technology has developed here.
Difficult working conditions during wartime shaped the spirit of collectivism and dedication. The employees understood the importance of their mission and sought to achieve high results. This legacy continues to live on today, supporting traditions and innovations in the field of aviation and astronautics.
Where the engine is, there is noise
– Today you are, among others, the scientific director of the Institute of Acoustics of Machines at Samara University. Speaking of acoustics, I assume that we are talking about the noises that occur during the operation of aircraft and rocket engines. And the big problem in aviation is how to reduce these noises. How naive is my question and what does your specialization mean – dynamics and vibroacoustics of complex technical systems?
– This area of scientific and technical activity combines the issues of several scientific disciplines. Vibroacoustics, as we understand it, is a set of tasks that are solved in complex machines and mechanisms. It is associated with the interaction of the working fluid – liquid or gas – with mechanical elements, as well as with the noise emitted by these machines and mechanisms. Translating this to more familiar topics, we can draw an analogy with a heart examination: when a person makes an echogram, he hears how the heart works through the vessels, including sound. We usually don't hear it, but when the instruments turn on, it becomes obvious that something significant is happening. Similar processes are observed in aviation and rocket and space technology.
The tasks of vibroacoustics are associated with reducing dynamic loads. Why dynamics and vibroacoustics? In static, when everything is in place, there are no noises, sounds and vibrations of the working environment. It is in dynamics that loads arise, which, on the one hand, ensure the functioning of mechanisms and machines, and on the other hand, are sources of vibro-acoustic effects on structural elements. These impacts can lead to both destruction and emergency situations; there are many examples of such cases.
Therefore, one of the most serious tasks in dynamics is to reduce the influence of vibrations and pulsations on the structural elements of machines. This requires an integrated approach to the analysis and control of vibroacoustic characteristics in order to ensure the reliability and safety of complex systems.
Our department, Institute of Acoustics of Machines, deals with the issues of vibroacoustics, which has historically developed due to a number of factors. Unfortunately, in December last year, Academician Vladimir Pavlovich Shorin, the founder of the school of dynamics of pipeline systems, passed away. It was from dynamics that the vibroacoustics of machines developed.
Academician Shorin was engaged in solving problems related to vibrations when Nikolai Dmitrievich Kuznetsov was developing engines. Reducing vibrations was a top priority. For this purpose, special vibration dampers were used, which were installed in the structural elements. However, where do the vibrations of the pipelines on the engine or in the aircraft come from? Their source is a hydraulic pump that delivers liquid in portions, creating pulsating feeds. It works up the whole system.
Understanding these complex mechanisms – how pumping units work and how they interact with pipelines that can reach hundreds of meters on airplanes – is an extremely important task. It is necessary to reduce the influence of pulsations of the working medium generated by the pump on the mechanical system and, accordingly, on the emitted noise. All these issues are being studied within the framework of the area related to the vibration acoustics of machines.
Reducing aircraft noise is a separate and huge problem. Vibroacoustics plays a key role in ensuring the reliability and safety of aviation systems. Research in this area is aimed at creating more effective solutions to minimize the negative effects of vibrations and noise on aircraft structures and mechanisms.
When we talk about active noise reduction, we mean the creation of acoustic waves in the opposite phase. In an airplane, by running an active noise cancellation system, we can feel silence, but in fact the dynamic processes that generate this noise remain. We create comfortable conditions for people, but the external effects remain the same. The study of issues related to noise reduction at the source is directly related to dynamics, vibrations and acoustics. All these aspects are combined into a single set of tasks to reduce noise at the source or install various devices – pulsation and vibration dampers.
These tasks are of great importance not only for aerospace engineering, but can also be applied in other fields, for example in the submarine fleet. Reducing noise and vibrations is critically important to improve the efficiency of machinery and ensure safety. Research in this area is aimed at developing new methods and technologies that will help minimize the negative impact of noise and vibrations on the operation of various systems.
– You mentioned the aquatic environment, and this led me to the idea that ballast is installed on the bottom of large ships. This heavy element is necessary to increase the stability of the vessel. However, I may be mistaken, but it seems that some heavy metal elements installed on the bottom to dampen vibrations can also be used in airplanes.
– When it comes to ships and surface objects, this is an understandable topic. However, in the case of airplanes, we are fighting for every kilogram of weight. If heavy elements such as blanks are transported instead of people or payloads, the aircraft will indeed become more stable. But the purpose of the flight is somewhat different. The stability of the aircraft must be ensured with the help of systems that guarantee this stability. In particular, this may include fuel generation systems from the center section and wings – these are separate serious problems that also contribute to ensuring the stability of the aircraft.
It is no coincidence that when emergency landings occur, sometimes it is necessary to dump fuel. This is necessary to ensure the reliability and stability of landings, not only because of the risk of fire, but also for the possibility of safe planning.
So the task you have set is really difficult. It is the same for submariners and surface divers, but for aircraft it is a completely different problem. Loading planes with extra weight is not the right decision, even if it can have some effect. In aviation, it is important to optimize the design and use technologies that provide the necessary stability without increasing weight.
About LRE and SFRD
– When I studied at MAI – however, it was a long time ago – one of the problems with the operation of aircraft was the distribution of fuel in the tanks. That is, the distribution of kerosene in the tanks of the aircraft so that it does not lead in one direction, and the behavior of fuel in the fuel tanks in the rocket, if it is not solid fuel, but liquid. Why did we develop the liquid direction in rocket engineering more, and in the USA – solid fuel?
– Historically, the development of rocket technology in our country began with the GIRD group (Group for the Study of Jet Propulsion), created in the late 1920s and early 1930s. It included such outstanding personalities as Sergei Pavlovich Korolev and Valentin Petrovich Glushko. It was from there that the development of liquid rocket engines began.
If we talk about solid-fuel engines, then it is worth contacting academician Yuri Semyonovich Solomonov. He will confirm that solid fuel technology is also actively developing and solving serious problems. The liquid engine industry is mainly associated with civilian areas of space exploration, whereas the solid fuel industry is more focused on defense needs.
These two areas complement each other and play an important role both in ensuring the country's defense capability and in solving many civilian tasks. The historical development of these areas is absolutely justified. In cases where it is necessary, tasks are solved not only with the help of liquid engines, but also in other ways. We can also observe this in the framework of current special operations.
Thus, it is important to understand that each of the technologies has its own unique advantages and purpose. The effective use of both liquid and solid fuel engines allows you to achieve your goals in various fields – from defense to civilian use.
– The Zvezda channel often shows aircraft engines with variable thrust vector. Our engines of the 5th generation AL-41F1, spin as if on a hinge, which is why the Su-57, Su-35 and others do pirouettes in the air that are incompatible with the existence of gravity. On the American F-35, the PW – F119-PW-100 engines are installed, which deviate from the axis only in one plane. This was shown in the movie Die Hard 4 with Bruce Willis, when the A–35 can take off vertically, land and even hover in the air. It looks spectacular. But in the USA, can't they make an engine nozzle that turns in different directions, like our planes?
By the way, our sources write about the appearance of engines with a variable thrust vector already of the 6th generation. They have an almost square nozzle section. There are photos in the public domain. Is it possible to outline the contours of the new engine, if they are available in open sources?
– Certain goals were set to control the nozzle not only to turn on the reverse during landing, but also to change the thrust vector of the engines using the nozzle. This task has been successfully solved by the engines we are talking about now. Why do Americans go their own way? They do it better in some aspects, worse in others. The main thing is for us to understand the trends and prospects in this field of unique mechanical engineering, because the aircraft engine is one of the most complex energy machines created by man. This is a truly unique product.
We need to maintain parity or even priority in development, especially where we can create unique designs that sometimes seem fantastic. Such designs are admired. Do you remember how aerobatics are demonstrated at the MAKS air show? It resembles a scene from the movie "Only the "old men" go into battle”, when the plane takes off and performs impossible maneuvers contrary to all the laws of physics.
In this context, it is important to note that the internal reserves of scientific schools are behind the successes, starting from TsAGI (Central Institute of Aerohydrodynamics) and ending with the names of such outstanding designers as Andrei Nikolaevich Tupolev, Sergey Vladimirovich Ilyushin, Nikolai Dmitrievich Kuznetsov, and others. These people united talented specialists around them who looked to the future and looked for ways to overcome existing limitations. When they were told that something was impossible, they replied, "Yes, it's impossible now, but we'll try." And they often succeeded.
An example of this is the story of the NK-33. When the lunar program was closed, Nikolai Dmitrievich Kuznetsov was instructed to destroy the engines and documentation prepared for it. However, his desire for innovation and development did not allow him to fulfill this order completely. He understood the value of the technologies he created and continued to work on improving them.
Nikolai Dmitrievich Kuznetsov showed the greatest wisdom when he said: "Guys, hide it so that no one can find either the engines or the documentation." Some of the materials were indeed destroyed, but about a hundred finished NK-33 engines were preserved. In the mid-1990s, this engine was exhibited at one of the aerospace salons, and the Americans were surprised when they saw it: "This can't be happening! How did you create this? Let's try it!"
This is a separate story. When we agreed with the Americans, they brought their specialists to us for testing. The engine was supposed to run for 110 seconds and produce 150 tons of thrust. It has successfully fulfilled this requirement. The Americans were at a loss: "How is that? Without refitting, they just pulled it out of the warehouse – and it works!" The engine has been in the warehouse for a quarter of a century, and now it is functioning.
Already on tests in the United States, the Americans proposed to increase the thrust to 175 tons. The engine worked for 110 seconds again and produced 175 tons of thrust. Then the Americans asked, "Can we increase it to 190 tons?" And again, the engine coped with the task: it worked for 110 seconds and produced 190 tons. The Americans were amazed: "Nothing burned down, nothing collapsed!" And finally they asked: "And will it be able to issue the nominal 150 tons again?" And it successfully worked 110 seconds in nominal mode again.
This happened around the mid-1990s. The Americans then said the sacramental phrase: "What a rich country Russia is that can allow such a unique product to lie in stock for a quarter of a century." But this engine is still working today. For example, the Soyuz-2 rocket.1B" light class uses the NK-33 engine. Can you imagine? 50 years have passed, and it is still functioning. Americans are watching this with interest.
When will we return the NK-93?
– Many of us are still haunted by the memories of the handsome Tu-144 aircraft. While you were still a student, you worked with its engine – it was developed by the famous Design Bureau of Nikolai Kuznetsov. It was called NK-144. What was its development like? Or is the engine forgotten and laid to rest along with the glider near GFRI (Gromov Flight Research Institute) in Zhukovsky?
– The NK-144 engine is located in our engine history center. Come and take a look. The Tu-144 is also presented at the training airfield of our University, which testifies to the preservation of the memory of this unique aircraft. The NK-144 engine was developed based on the technologies used to create strategic aviation engines. Unique developments continue and are used in modern products.
– Dear Evgeny Vladimirovich, our conversation is coming to an end. Finally, the main question. When the first issues of the newspaper Argumenty Nedeli were published, I raised the topic of introducing the NK-93 engine into aviation. Even then, almost 20 years ago, it was said that it was ahead of its time in terms of technology, fuel consumption, and noise. The engine was even hidden from President Putin on MAKS, so that, God forbid, he would not see and give the command to use it. I wish now it would be suitable for both Il-96 and Il-79, not to mention the launch of the An-124 analog into a new series. Do you think the train for NK–93 has gone irrevocably? In the West, engines with such a degree of two-circuit design seem to have already appeared.
– The question is really difficult for me, since I was a participant in one of the conferences in the early 1990s, at which Nikolai Dmitrievich Kuznetsov presented a report on the NK-93 engine. All participants of the conference watched with great interest what this engine had to offer: the built-in parameters provided both efficiency and reliability.
About 35 years have passed since then, and, of course, a lot has changed. However, the idea itself remains relevant, and the accumulated experience invested in the development of the NK-93 deserves serious attention. At one time, the Americans, buying NK-33 engines from Kuznetsov's company, did everything possible to ensure that the NK-93 did not develop. It was a unique competitor.
Now the question is: where is the aircraft on which such an engine can be installed? Yes, it is one-on-one with the upgraded NK-93. But where is the IL-96-400 or some other "Il" that these engines can be used on? It is necessary not only to install them, but also to bring them to a serial sample that can be used for many years. The idea of NK-93 has not just remained – it lives on. This engine has become a symbol of the struggle between good and evil. It remains a symbol of this struggle: someone wants to destroy its developments, and someone seeks to preserve them. Good usually wins.
Technological and design achievements have not been forgotten – they are actively used in our aviation. It is important to remember that an aircraft engine is one of the most complex energy machines created by man. This unique product requires constant attention and development.
We must maintain parity or even priority in this area, especially where we have the opportunity to create such unique designs. These achievements are admirable and confirm the importance of our science and technology.
Source: Argumenty Nedeli
