A typical passenger plane flies at a speed of about 900 km/h. A military fighter jet can develop approximately three times higher speed. However, modern engineers from the Russian Federation and other countries of the world are actively developing even faster machines - hypersonic aircraft. What are the specifics of the relevant concepts?
Criteria for a hypersonic aircraft
What is a hypersonic aircraft? This is usually understood as a device capable of flying at a speed many times higher than that of sound. Researchers' approaches to determining its specific indicator vary. A common methodology is that an aircraft should be considered hypersonic if it is a multiple of the speed indicators of the fastest modern supersonic vehicles. Which are about 3-4 thousand km/h. That is, a hypersonic aircraft, if you adhere to this methodology, must reach a speed of 6 thousand km/h.
Unmanned and controlled vehicles
The approaches of researchers may also differ in terms of determining the criteria for classifying a particular device as an aircraft. There is a version that only those machines that are controlled by a person can be classified as such. There is a point of view according to which an unmanned vehicle can also be considered an aircraft. Therefore, some analysts classify machines of the type in question into those that are subject to human control and those that function autonomously. Such a division can be justified because unmanned vehicles may have much more impressive technical characteristics, for example, in terms of overload and speed.
At the same time, many researchers consider hypersonic aircraft as a single concept, for which the key indicator is speed. It doesn’t matter whether a person sits at the helm of the device or the machine is controlled by a robot - the main thing is that the plane is fast enough.
Take off - independently or with assistance?
There is a widespread classification of hypersonic aircraft, which is based on classifying them into the category of those that are capable of taking off on their own, or those that require placement on a more powerful carrier - a rocket or a cargo plane. There is a point of view according to which it is right to include mainly those that are capable of taking off independently or with minimal involvement of other types of equipment as devices of the type under consideration. However, those researchers who believe that the main criterion characterizing a hypersonic aircraft, speed, should be paramount in any classification. Whether the device is classified as unmanned, controlled, capable of taking off on its own or with the help of other machines - if the corresponding indicator reaches the above values, it means we're talking about about hypersonic aircraft.
Main problems of hypersonic solutions
The concepts of hypersonic solutions are many decades old. Throughout the years of development of the corresponding type of devices, world engineers have been solving a number of significant problems that objectively prevent the production of “hypersonics” from being put into production - similar to organizing the production of turboprop aircraft.
The main difficulty in designing hypersonic aircraft is creating an engine that can be sufficiently energy efficient. Another problem is lining up the necessary apparatus. The fact is that the speed of a hypersonic aircraft in the values that we discussed above implies strong heating of the body due to friction with the atmosphere.
Today we will look at several examples of successful prototypes of aircraft of the corresponding type, the developers of which were able to make significant progress in successfully solving the noted problems. Let us now study the most famous world developments in terms of creating hypersonic aircraft of the type in question.
from Boeing
The fastest hypersonic aircraft in the world, according to some experts, is the American Boeing X-43A. Thus, during testing of this device, it was recorded that it reached speeds exceeding 11 thousand km/h. That is approximately 9.6 times faster
What is especially remarkable about the X-43A hypersonic aircraft? The characteristics of this aircraft are as follows:
The maximum speed recorded in tests is 11,230 km/h;
Wingspan - 1.5 m;
Body length - 3.6 m;
Engine - direct-flow, Supersonic Combustion Ramjet;
Fuel - atmospheric oxygen, hydrogen.
It can be noted that the device in question is one of the most environmentally friendly. The fact is that the fuel used practically does not emit harmful combustion products.
The X-43A hypersonic aircraft was developed jointly by NASA engineers, as well as Orbical Science Corporation and Minocraft. was created about 10 years ago. About $250 million was invested in its development. The conceptual novelty of the aircraft in question is that it was conceived with the aim of testing the latest technology for providing propulsion.
Development from Orbital Science
The Orbital Science company, which, as we noted above, took part in the creation of the X-43A, also managed to create its own hypersonic aircraft - the X-34.
Its top speed is more than 12 thousand km/h. True, during practical tests it was not achieved - moreover, it was not possible to achieve the indicator shown by the X43-A aircraft. The aircraft in question is accelerated when the Pegasus rocket, which operates on solid fuel, is activated. The X-34 was first tested in 2001. The aircraft in question is significantly larger than the Boeing aircraft - its length is 17.78 m, its wingspan is 8.85 m. The maximum flight altitude of the hypersonic vehicle from Orbical Science is 75 kilometers.
Aircraft from North American
Another famous hypersonic aircraft is the X-15, produced by North American. Analysts classify this apparatus as experimental.
It is equipped, which gives some experts a reason not to classify it, in fact, as an aircraft. However, the presence of rocket engines allows the device, in particular, to perform So, during one of the tests in this mode, it was tested by pilots. The purpose of the X-15 device is to study the specifics of hypersonic flights, evaluate certain design solutions, new materials, and control features of such machines in various layers of the atmosphere. It is noteworthy that it was approved back in 1954. The X-15 flies at a speed of more than 7 thousand km/hour. Its flight range is more than 500 km, its altitude exceeds 100 km.
The fastest production aircraft
The hypersonic vehicles we studied above actually belong to the research category. It will be useful to consider some production models of aircraft that are close in characteristics to hypersonic ones or are (according to one methodology or another) hypersonic ones.
Among such machines is the American development of the SR-71. Some researchers are not inclined to classify this aircraft as hypersonic, since its maximum speed is about 3.7 thousand km/h. Among its most notable characteristics is its take-off weight, which exceeds 77 tons. The length of the device is more than 23 m, the wingspan is more than 13 m.
The Russian MiG-25 is considered one of the fastest military aircraft. The device can reach speeds of more than 3.3 thousand km/h. Maximum take-off weight Russian plane- 41 tons.
Thus, in the market for serial solutions with characteristics close to hypersonic ones, the Russian Federation is among the leaders. But what can be said about Russian developments regarding “classic” hypersonic aircraft? Are engineers from the Russian Federation capable of creating a solution that is competitive with machines from Boeing and Orbital Scence?
Russian hypersonic vehicles
At the moment, the Russian hypersonic aircraft is under development. But it is going quite actively. We are talking about the Yu-71 aircraft. Its first tests, judging by media reports, were carried out in February 2015 near Orenburg.
It is assumed that the aircraft will be used for military purposes. Thus, a hypersonic vehicle will be able, if necessary, to deliver destructive weapons over considerable distances, monitor the territory, and also be used as an element of attack aircraft. Some researchers believe that in 2020-2025. The Strategic Missile Forces will receive about 20 aircraft of the corresponding type.
There is information in the media that the Russian hypersonic aircraft in question will be mounted on the Sarmat ballistic missile, which is also at the design stage. Some analysts believe that the Yu-71 hypersonic vehicle being developed is nothing more than a warhead that will have to be separated from the ballistic missile at the final stage of flight and then, thanks to the high maneuverability characteristic of the aircraft, overcome missile defense systems.
Project "Ajax"
Among the most notable projects related to the development of hypersonic aircraft is Ajax. Let's study it in more detail. The Ajax hypersonic aircraft is a conceptual development of Soviet engineers. In the scientific community, conversations about it began back in the 80s. Among the most notable characteristics is the presence of a thermal protection system, which is designed to protect the case from overheating. Thus, the developers of the Ajax apparatus proposed a solution to one of the “hypersonic” problems we identified above.
The traditional thermal protection scheme for aircraft involves placing special materials on the body. The Ajax developers proposed a different concept, according to which it was supposed not to protect the device from external heat, but to let heat inside the machine, while simultaneously increasing its energy resource. The main competitor of the Soviet aircraft was considered the hypersonic aircraft “Aurora”, created in the USA. However, due to the fact that designers from the USSR significantly expanded the capabilities of the concept, new development was assigned a wide range of tasks, in particular research ones. We can say that the Ajax is a hypersonic multi-purpose aircraft.
Let's take a closer look at the technological innovations proposed by engineers from the USSR.
So, the Soviet developers of Ajax proposed using the heat generated as a result of friction of the aircraft body with the atmosphere and converting it into useful energy. Technically, this could be realized by placing additional shells on the device. As a result, something like a second corps was formed. Its cavity was supposed to be filled with some kind of catalyst, for example, a mixture of flammable material and water. Thermal insulating layer made of hard material, in Ajax it was supposed to be replaced with a liquid one, which, on the one hand, was supposed to protect the engine, on the other, it would promote a catalytic reaction, which, meanwhile, could be accompanied by an endothermic effect - the movement of heat from the outside of the body to the inside. Theoretically, the cooling of the external parts of the device could be anything. The excess heat, in turn, was supposed to be used to increase the efficiency of the aircraft engine. At the same time, this technology would make it possible to generate free hydrogen as a result of the reaction of the fuel.
At the moment, there is no information available to the general public about the continuation of the development of Ajax, however, researchers consider the introduction of Soviet concepts into practice to be very promising.
Chinese hypersonic vehicles
China is becoming a competitor to Russia and the United States in the hypersonic solutions market. Among the most famous developments of engineers from China is the WU-14 aircraft. It is a hypersonic controlled glider mounted on a ballistic missile.
An ICBM launches an aircraft into space, from where the vehicle sharply dives down, developing hypersonic speed. The Chinese device can be mounted on various ICBMs with a range from 2 to 12 thousand km. It was found that during tests, the WU-14 was able to reach a speed exceeding 12 thousand km/h, thus becoming the fastest hypersonic aircraft according to some analysts.
At the same time, many researchers believe that it is not entirely legitimate to classify the Chinese development as an aircraft. Thus, there is a widespread version according to which the device should be classified specifically as a warhead. And very effective. When flying downward at the specified speed, even the most modern missile defense systems will not be able to guarantee interception of the corresponding target.
It can be noted that Russia and the United States are also developing hypersonic vehicles used for military purposes. At the same time, the Russian concept, according to which it is supposed to create machines of the appropriate type, differs significantly, as evidenced by data in some media, from the technological principles implemented by the Americans and the Chinese. Thus, developers from the Russian Federation are concentrating their efforts in the field of creating aircraft equipped with a ramjet engine that can be launched from the ground. Russia plans to cooperate in this direction with India. Hypersonic vehicles created by Russian concept, according to some analysts, are characterized by lower cost and wider scope.
At the same time, the Russian hypersonic aircraft, which we mentioned above (Yu-71), suggests, as some analysts believe, deployment on ICBMs. If this thesis turns out to be correct, then we can say that engineers from the Russian Federation are working simultaneously in two popular conceptual directions in the construction of hypersonic aircraft.
Summary
So, probably the fastest hypersonic aircraft in the world, if we talk about aircraft regardless of their classification, is still the Chinese WU-14. Although you need to understand that real information about it, including those related to tests, may be classified. This is quite consistent with the principles of Chinese developers, who often strive to keep their military technologies secret at all costs. The speed of the fastest hypersonic aircraft is more than 12 thousand km/h. The American development of the X-43A is “catching up” with it - many experts consider it to be the fastest. Theoretically, the hypersonic aircraft X-43A, as well as the Chinese WU-14, can catch up with the development from Orbical Science, designed for a speed of more than 12 thousand km/h.
The characteristics of the Russian Yu-71 aircraft are not yet known to the general public. It is quite possible that they will be close to the parameters of the Chinese aircraft. Russian engineers are also developing a hypersonic aircraft capable of taking off independently, rather than based on an ICBM.
Current projects of researchers from Russia, China and the United States are in one way or another related to the military sphere. Hypersonic aircraft, regardless of their possible classification, are considered primarily as carriers of weapons, most likely nuclear. However, in the works of researchers from various countries Around the world, there are theses that “hypersound,” like nuclear technology, may well be peaceful.
The issue is the emergence of affordable and reliable solutions that make it possible to organize mass production of machines of the appropriate type. The use of such devices is possible in the widest range of sectors of economic development. Hypersonic aircraft are likely to find greatest demand in the space and research industries.
As production technologies for the corresponding machines become cheaper, people may begin to show interest in investing in such projects. transport businesses. Industrial corporations and providers of various services may begin to consider “hypersonic” as a tool for increasing business competitiveness in terms of organizing international communications.
First, of course, you should decide, how much is hypersound? It is generally accepted that hypersonic speed is a speed above 5 Mach, that is, more than five, and to put it simply, it is a speed five times the speed of sound.
Are you wondering how much is this in kilometers per hour? From 5380 km/h to 6120 km/h depending on the parameters of the environment (for an airplane - air), that is, on the density of the air, which is different at different flight altitudes. So, for ease of perception, it is still better to use Mach numbers. If the aircraft speed exceeds 5 Mach, this is hypersonic speed.
Actually, why exactly 5 M? The value 5 was chosen because at this speed ionization of the gas flow and other physical changes begin to be observed, which of course affects its properties.
These changes are especially noticeable for the engine, conventional turbojet engines simply cannot operate at such a speed, a fundamentally different engine is needed, rocket or ramjet (although in fact it is not so different, it just lacks a compressor and turbine, and it performs its function in the same way: it compresses the air at the inlet, mixes it with fuel, burns it in the combustion chamber, and receives a jet stream at the outlet).
In fact, a ramjet engine is a pipe with a combustion chamber, very simple and efficient at high speed. But such an engine has a huge drawback: it needs a certain initial speed to work (it doesn’t have its own compressor, there’s nothing to compress the air at low speed with).
History of speed
In the 50s there was a struggle to achieve the speed of sound. When engineers and scientists understood how an airplane behaves at speeds above the speed of sound and learned how to create aircraft designed for such flights, it was time to move on. Make planes fly even faster.
In 1967, the American experimental aircraft X-15 reached a speed of 6.72 Mach (7274 km/h). It was equipped with a rocket engine and flew at altitudes from 81 to 107 km (100 km is the Karman line, the conventional boundary of the atmosphere and space). Therefore, it is more correct to call the X-15 not an airplane, but a rocket plane. He could not take off on his own; he needed a booster plane. But still, it was a hypersonic flight. Moreover, the X-15 flew from 1962 to 1968, and 7 flights on the X-15 were made by the same Neil Armstrong.
It is worth understanding that flights outside the atmosphere, no matter how fast they are, cannot be correctly considered hypersonic, because the density of the medium in which the aircraft moves is very low. The effects inherent in supersonic or hypersonic flight simply will not exist.
In 1965, the YF-12 (prototype of the famous SR-71) reached a speed of 3,331.5 km/h, and in 1976 the production SR-71 itself reached 3,529.6 km/h. This is “only” 3.2–3.3 M. Far from hypersonic, but for flights at this speed in the atmosphere it was necessary to develop special engines that operated in normal mode at low speeds, and in ramjet mode at high speeds, and for pilots - special life support systems (suits and cooling systems), since the plane was heating up too much. Later, these spacesuits were used for the Shuttle project. Very for a long time The SR-71 was the fastest aircraft in the world (it stopped flying in 1999).
The Soviet Mig-25R could theoretically reach a speed of 3.2 Mach, but the operational speed was limited to 2.83 Mach.
In the same 60s, in the USA and USSR there were space projects X-20 “Dyna Soar” and “Spiral”, respectively. For Spiral, it was initially planned to use a hypersonic booster aircraft, then a supersonic one, and then the project was completely closed. The American project suffered the same fate.
In general, the projects of hypersonic aircraft of that time were connected with flights outside the atmosphere. It cannot be otherwise; at “low” altitudes the density and, accordingly, the resistance are too high, which leads to many negative factors that could not be overcome at that time.
Present tense
The military, as usual, is behind all promising research. In the case of hypersonic speeds, this also occurs. Currently, research is being conducted mainly in the direction of spacecraft, hypersonic cruise missiles and so-called hypersonic warheads. Now we are talking about “real” hypersound, flights in the atmosphere. Please note that work on hypersonic speeds was in an active phase in the 60-70s, then all projects were closed. They returned to speeds above 5 M only at the turn of the 2000s. When technology made it possible to create efficient ramjet engines for hypersonic flights.
In 2001, an unmanned aerial vehicle with a ramjet engine made its first flight.
Boeing X-43. Already in 2014, it accelerated to a speed of 9.6 M (11,200 km/h). Although the X-43 was designed for speeds 7 times the speed of sound. Moreover, the record was not set in space, but at an altitude of only 33,500 meters.
The X-43 in the photo looks like a small black triangle attached to a booster rocket.
In 2009, testing began on a ramjet engine for the Boeing X-51A Waverider cruise missile. In 2013, the X-51A accelerated to hypersonic speed - 5.1 M at an altitude of 21,000 meters.
Similar projects are being carried out at various stages by other countries: Germany (SHEFEX), Great Britain (Skylon), Russia (Cold and Needle), China (WU-14) and even India (Brahmos), Australia (ScramSpace) and Brazil (14-X).
GLL-31 project "Cold"
Interesting project aircraft for flying at hypersonic speeds in the atmosphere, the American Falcon HTV-2, is considered a failure. Presumably, Falcon was able to accelerate to a speed that was enormous for the atmosphere - 23 Mach. But only presumably, since all the experimental devices simply burned out.
All of the listed aircraft (except Skylon) cannot independently reach the speed necessary for the operation of a ramjet engine and use different accelerators. But Skylon is still only a project that has not yet made a single test flight.
The distant future of hypersound
There are also civilian projects of hypersonic aircraft for transporting passengers. These are the European SpaceLiner with one type of engine and the ZEHST which should use as many as 3 types of engine in different flight modes. Other countries are also working on their projects.
Such liners will presumably be able to transport passengers from London to New York in just an hour. We will be able to fly such aircraft no earlier than the 40s and 50s of the 21st century. In the meantime, hypersonic speeds remain the domain of military or spacecraft.
Honorable CEO and honorary general designer of JSC VPK NPO Mashinostroeniya, professor at Bauman Moscow State Technical University - on the creation and development of hypersonic aircraftThe creation and development of combat hypersonic aircraft is one of the biggest secrets not only in Russia, but also in the USA, China and other countries of the world. Information about them belongs to the “top secret” category. In an exclusive interview with Izvestia, the legendary designer of rocket and space technology, Herbert Efremov, who devoted more than 30 years to the creation of hypersonic technology, explained what hypersonic vehicles are and what difficulties are encountered in their development.
— Herbert Aleksandrovich, there is a lot of talk now about the creation of hypersonic aircraft, but most of the information about them is closed to the general public...
— Let's start with the fact that products that develop hypersonic speed have been created a long time ago. For example, these are ordinary heads of intercontinental ballistic missiles. Entering the Earth's atmosphere, they develop hypersonic speed. But they are uncontrollable and fly along a certain trajectory. And their interceptions by missile defense (BMD) systems have been demonstrated more than once.
As another example, I will give our strategic cruise missile “Meteorite”, which once flew at an insane speed of Mach 3 - about 1000 m/s. Literally on the verge of hypersound (hypersonic speeds start at Mach 4.5 - Izvestia). But the main task of modern hypersonic aircraft (HZLA) is not just to fly somewhere quickly, but to carry out a combat mission with high efficiency in the face of strong enemy opposition. For example, the Americans alone have 65 Arleigh Burke-class destroyers with anti-missile defenses at sea. There are also 22 Ticonderoga-class anti-missile cruisers, 11 aircraft carriers - each of which is based on up to a hundred aircraft capable of creating an almost impenetrable missile defense system.
— Are you saying that speed in itself does not solve anything?
— Roughly speaking, hypersonic speed is 2 km/s. To cover 30 km, you need to fly for 15 seconds. At the final part of the trajectory, when the hypersonic aircraft approaches the target, the enemy’s anti-missile and air defense systems will definitely be deployed, which the GZV will detect. And to get ready modern systems Air defense and missile defense, if they are deployed in positions, require a matter of seconds. Therefore, for the effective combat use of GZLA, speed alone will not be enough if you have not ensured electronic stealth and invincibility for air defense/missile defense systems during the final phase of the flight. Both speed and the capabilities of radio engineering protection of the device with its own radio jamming stations will play a role here. Everything is in a complex.
— You say that there must be not only speed, but the product must be controllable in order to achieve the goal. Tell us about the possibility of controlling a vehicle in a hypersonic flow.
— All hypersonic vehicles fly in plasma. And nuclear combat heads fly in plasma, and everything that exceeds speeds of Mach 4, especially 6. An ionized cloud is formed around, and not just a flow with turbulence: the molecules are still broken into charged particles. Ionization affects communication and the passage of radio waves. It is necessary for the control and navigation systems of the GZV to penetrate this plasma at these flight speeds.
On the "Meteorite" we had to be sure to see the earth's surface with radar. Navigation was provided by comparing location images from on board the rocket with a video standard embedded in the system. It was impossible otherwise. “Caliber” and other cruise missiles can fly like this: I used a radio altimeter to reconnaissance the terrain - here is a hill, here is a river, here is a valley. But this is possible when you fly at an altitude of hundreds of meters. And when you rise to a height of 25 km, you cannot distinguish any hillocks with a radio altimeter. Therefore, we found certain areas on the ground, compared them with what was recorded in the video reference, and determined the displacement of the rocket to the left or right, forward, backward and by how much.
— In many textbooks for dummies, hypersonic flight in the atmosphere is compared to sliding on sandpaper due to very high resistance. How true is this statement?
- A little inaccurate. At hypersound, all sorts of turbulent flows, vortices and shaking of the device begin. Thermal intensity regimes change depending on whether the flow on the surface is laminar (smooth) or with disruptions. There are a lot of difficulties. For example, the heat load increases sharply. If you fly at a speed of Mach 3, the heating of the GZLA skin is about 150 degrees in the atmosphere, depending on the altitude. The higher the flight altitude, the less heating. But at the same time, if you fly at twice the speed, the heating will be much greater. Therefore, new materials need to be used.
— What can be given as an example of such materials?
— Various carbon materials. Even fiberglass is used on nuclear warheads that sit on intercontinental “hundreds” (UR-100 ballistic missiles developed by NPO Mashinostroyenia). With hypersound, the temperature is many thousands of degrees. But steel holds only 1200 degrees Celsius. These are crumbs.
Hypersonic temperatures carry away the so-called “sacrificial layer” (the coating layer that is consumed during the flight of the aircraft. - Izvestia). Therefore, the shell of nuclear warheads is designed so that most of it will be “eaten” by hypersound, while the internal filling will be preserved. But GZLA cannot have a “sacrificial layer.” If you fly on a controlled product, you must maintain an aerodynamic shape. You cannot “blunt” the product so that the toe and edges of the wings, etc., burn. This, by the way, was done on the American Shuttles and on our Buran. There, graphite materials were used as thermal protection.
— Is it correct when they write in popular science literature that a hypersonic atmospheric vehicle should have a design as a single monolithic solid body?
- Not necessary. They can consist of compartments and different elements.
- That is, it is possible classic scheme rocket structure?
- Certainly. Select materials, order new developments, if necessary, check, work on benches, in flight, correct if something goes wrong. You also need to be able to measure this with hundreds of telemetric sensors of incredible complexity.
— Which engine is better - solid fuel or liquid for a hypersonic vehicle?
— Solid fuel is not suitable here at all, because it can accelerate, but it is impossible to fly for a long time with it. Such engines are used in ballistic missiles such as “Bulava” and “Topol”. In the case of GZLA, this is unacceptable. On our Yakhont missile (an anti-ship cruise missile, part of the Bastion complex. - Izvestia), only the starting accelerator is solid fuel. Then it flies on a liquid ramjet engine.
There are attempts to make a ramjet engine with an internal content of solid fuel, which is spread throughout the combustion chamber. But it is also not enough for long ranges.
For liquid fuel, you can make the tank smaller, of any shape. One of the "Meteorites" flew with tanks in the wings. It was tested because we had to achieve a range of 4-4.5 thousand km. And he flew on an air-breathing engine running on liquid fuel.
— What is the difference between an air-breathing engine and a liquid-propellant jet engine?
— A liquid jet engine contains an oxidizer and a fuel in separate tanks, which are mixed in the combustion chamber. An air-jet engine is powered by a single fuel: kerosene, decilin or bicilin. The oxidizing agent is the incoming air oxygen. Bicilin (fuel produced from vacuum gas oil using hydrogenation processes - Izvestia) was precisely developed according to our order for Meteorit. This liquid fuel has a very high density, which makes it possible to make a smaller tank.
— There are known photographs of hypersonic aircraft precisely from jet engine. They all have an interesting shape: not streamlined, but rather angular and square. Why?
— You are probably talking about the X-90, or, as it is called in the West, AS-X-21 Koala (the first Soviet experimental GZLA. — Izvestia). Well, yes, this is a clumsy bear. In front are the so-called “boards” and “wedges” (structural elements with sharp corners and protrusions. - Izvestia). Everything is done to make the air flow entering the engine acceptable for combustion and normal combustion of the fuel. To do this, we create so-called shock waves (a sharp increase in pressure, density, temperature of a gas and a decrease in its speed when a supersonic flow encounters any obstacle. - Izvestia). Jumps are formed precisely on “boards” and “wedges” - those structural elements that dampen air speed.
On the way to the engine there may be a second shock wave, or a third. The whole nuance is that air should not enter the combustion chamber at the same speed as the GZLA flies. It definitely needs to be reduced. And very much so. Preferably to subsonic values, for which everything has been worked out, checked and tested. But this is precisely the problem that the creators of the GZLA are trying to solve and have not solved in 65 years.
As soon as you jump beyond Mach 4.5, in such high-speed movement air particles quickly slip into the engines. And you must “bring together” the atomized fuel and the oxidizer - atmospheric oxygen. This interaction must be with high combustion efficiency. Interaction should not be disrupted by some kind of hesitation or extra breath inside. No one has yet figured out how to do this.
— Is it possible to create a GZLA for civilian needs, for transporting passengers and cargo?
- Maybe. At one of the Paris air shows, an aircraft developed by the French together with the British was shown. A turbojet engine lifts it to altitude, and then the car accelerates to approximately Mach 2. The ramjet engines then open, propelling the aircraft to Mach 3.5 or Mach 4. And then he flies at an altitude of about 30 kilometers somewhere from New York to Japan. Before landing, the reverse mode is activated: the machine descends, switches to a turbojet engine, like a regular airplane, enters the atmosphere and lands. Hydrogen is considered as a fuel as the most high-calorie substance.
— Currently, Russia and the United States are most actively developing hypersonic aircraft. Can you evaluate the success of our opponents?
- As for grades, I can say - let the guys work. For 65 years, they haven’t really done anything. At speeds from Mach 4.5 to 6, there is not a single actually made GZLA.
First, of course, you should decide, how much is hypersound? It is generally accepted that hypersonic speed is a speed above 5 Mach, that is, more than five Mach numbers, and, quite simply, it is a speed five times the speed of sound.
Are you wondering how much is this in kilometers per hour? From 5380 km/h to 6120 km/h depending on the parameters of the environment (for an airplane - air), that is, on the density of the air, which is different at different flight altitudes. So, for ease of perception, it is still better to use Mach numbers. If the aircraft speed exceeds 5 Mach, this is hypersonic speed.
Actually, why exactly 5 M? The value 5 was chosen because at this speed ionization of the gas flow and other physical changes begin to be observed, which of course affects its properties. These changes are especially noticeable for the engine, conventional turbojet engines simply cannot operate at such a speed, a fundamentally different engine is needed, rocket or ramjet (although in fact it is not so different, it just lacks a compressor and turbine, and it performs its function in the same way: it compresses the air at the inlet, mixes it with fuel, burns it in the combustion chamber, and receives a jet stream at the outlet).
In fact, a ramjet engine is a pipe with a combustion chamber, very simple and efficient at high speed. But such an engine has a huge drawback: it needs a certain initial speed to work (it doesn’t have its own compressor, there’s nothing to compress the air at low speed with).
History of speed
In the 50s there was a struggle to achieve the speed of sound. When engineers and scientists understood how an airplane behaves at speeds above the speed of sound and learned how to create aircraft designed for such flights, it was time to move on. Make planes fly even faster.
In 1967, the American experimental aircraft X-15 reached a speed of 6.72 Mach (7274 km/h). It was equipped with a rocket engine and flew at altitudes from 81 to 107 km (100 km is the Karman line, the conventional boundary of the atmosphere and space). Therefore, it is more correct to call the X-15 not an airplane, but a rocket plane. He could not take off on his own; he needed a booster plane. But still, it was a hypersonic flight. Moreover, the X-15 flew from 1962 to 1968, and 7 flights on the X-15 were made by the same Neil Armstrong.
It is worth understanding that flights outside the atmosphere, no matter how fast they are, cannot be correctly considered hypersonic, because the density of the medium in which the aircraft moves is very low. The effects inherent in supersonic or hypersonic flight simply will not exist.
In 1965, the YF-12 (prototype of the famous SR-71) reached a speed of 3,331.5 km/h, and in 1976 the production SR-71 itself reached 3,529.6 km/h. This is “only” 3.2-3.3 M. Far from being hypersonic, but for flights at this speed in the atmosphere it was necessary to develop special engines that operated in normal mode at low speeds, and in ramjet mode at high speeds, and for pilots - special life support systems (suits and cooling systems), since the plane was heating up too much. Later, these spacesuits were used for the Shuttle project. For a very long time, the SR-71 was the fastest aircraft in the world (it stopped flying in 1999).
The Soviet Mig-25R could theoretically reach a speed of 3.2 Mach, but the operational speed was limited to 2.83 Mach.
In the same 60s, in the USA and USSR there were space projects X-20 “Dyna Soar” and “Spiral”, respectively. For Spiral, it was initially planned to use a hypersonic booster aircraft, then a supersonic one, and then the project was completely closed. The American project suffered the same fate.
In general, the projects of hypersonic aircraft of that time were connected with flights outside the atmosphere. It cannot be otherwise; at “low” altitudes the density and, accordingly, the resistance are too high, which leads to many negative factors that could not be overcome at that time.
Present tense
The military, as usual, is behind all promising research. In the case of hypersonic speeds, this also occurs. Currently, research is being conducted mainly in the direction of spacecraft, hypersonic cruise missiles and so-called hypersonic warheads. Now we are talking about “real” hypersound, flights in the atmosphere.
Please note that work on hypersonic speeds was in an active phase in the 60-70s, then all projects were closed. They returned to speeds above 5 M only at the turn of the 2000s. When technology made it possible to create efficient ramjet engines for hypersonic flights.
In 2001, an unmanned aerial vehicle with a ramjet engine made its first flight.
Boeing X-43. Already in 2014, it accelerated to a speed of 9.6 M (11,200 km/h). Although the X-43 was designed for speeds 7 times the speed of sound. Moreover, the record was not set in space, but at an altitude of only 33,500 meters.
In 2009, testing began on a ramjet engine for the Boeing X-51A Waverider cruise missile. In 2013, the X-51A accelerated to hypersonic speed - 5.1 M at an altitude of 21,000 meters.
Similar projects are being carried out at various stages by other countries: Germany (SHEFEX), Great Britain (Skylon), Russia (Cold and Needle), China (WU-14) and even India (Brahmos), Australia (ScramSpace) and Brazil (14-X).
An interesting project of an aircraft for flying at hypersonic speeds in the atmosphere, the American Falcon HTV-2, is considered a failure. Presumably, Falcon was able to accelerate to an enormous speed for the atmosphere - 23 Mach. But only presumably, since all the experimental devices simply burned out.
All of the listed aircraft (except Skylon) cannot independently reach the speed necessary for the operation of a ramjet engine and use different accelerators. But Skylon is still only a project that has not yet made a single test flight.The distant future of hypersound
There are also civilian projects of hypersonic aircraft for transporting passengers. These are the European SpaceLiner with one type of engine and the ZEHST which should use as many as 3 types of engine in different flight modes. Other countries are also working on their projects.
Such liners will presumably be able to transport passengers from London to New York in just an hour. We will be able to fly such aircraft no earlier than the 40s and 50s of the 21st century. In the meantime, hypersonic speeds remain the domain of military or spacecraft.
Promising Russian bomber - a response to the concept of a rapid global strike?
The competition for aviation to master hypersonic speeds began during the Cold War. In those years, designers and engineers of the USSR, USA and other developed countries designed new aircraft capable of flying 2-3 times faster speed sound. The race for speed gave rise to many discoveries in the field of aerodynamics of flight in the atmosphere and quickly reached the limits of the physical capabilities of pilots and the cost of manufacturing an aircraft.
As a result, rocket design bureaus were the first to master hypersound in their creations - intercontinental ballistic missiles (ICBMs) and launch vehicles. When launching satellites into near-Earth orbits, the rockets reached speeds of 18,000 – 25,000 km/h. This far exceeded the maximum parameters of the fastest supersonic aircraft, both civilian (Concord = 2150 km/h, Tu-144 = 2300 km/h) and military (SR-71 = 3540 km/h, MiG-31 = 3000 km/h) hour).
Separately, I would like to note that when designing the supersonic interceptor MiG-31, aircraft designer G.E. Lozino-Lozinsky used advanced materials (titanium, molybdenum, etc.) in the airframe design, which allowed the aircraft to reach a record altitude for manned flight (MiG-31D) and a maximum speed of 7000 km/h in the upper atmosphere. In 1977, test pilot Alexander Fedotov set an absolute world flight altitude record of 37,650 meters on its predecessor, the MiG-25 (for comparison, the SR-71’s maximum flight altitude was 25,929 meters). Unfortunately, engines for flights at high altitudes in conditions of a highly rarefied atmosphere had not yet been created, since these technologies were only being developed in the bowels of Soviet research institutes and design bureaus as part of numerous experimental works.
A new stage in the development of hypersound technologies has become research projects to create aerospace systems that combined the capabilities of aviation (aerobatics and maneuvers, landing on runways) and spacecraft (entry into orbit, orbital flight, descent from orbit). In the USSR and the USA, these programs were partially worked out, revealing to the world the space orbital planes “Buran” and “Space Shuttle”.
Why partially? The fact is that the launch of the aircraft into orbit was carried out using a launch vehicle. The cost of the launch was enormous, about 450 million dollars (according to the Space Shuttle program), which was several times higher than the cost of the most expensive civil and military aircraft, and did not allow making the orbital aircraft a mass product. The need to invest enormous amounts of money in creating infrastructure that would ensure ultra-fast intercontinental flights (cosmodromes, flight control centers, fuel and refueling complexes) finally buried the prospect of passenger transportation.
The only customer that is at least somehow interested in hypersonic vehicles is the military. True, this interest was episodic. The military programs of the USSR and the USA to create aerospace aircraft followed different paths. They were most consistently implemented in the USSR: from the project to create a PKA (planning spacecraft) before MAKS (multi-purpose aviation space system) and Buran, a consistent and continuous chain of scientific and technical foundations was built, on the basis of which the foundation for future experimental flights of hypersonic aircraft prototypes was created.
Missile design bureaus continued to improve their ICBMs. With the advent of modern air defense and missile defense systems capable of shooting down ICBM warheads at great distances, new requirements began to be placed on the striking elements of ballistic missiles. The warheads of the new ICBMs were supposed to overcome enemy air and missile defenses. This is how combat units appeared that were capable of overcoming air defense at hypersonic speeds (M=5-6).
The development of hypersonic technologies for the warheads of ICBMs made it possible to launch several projects to create defensive and offensive hypersonic weapons - kinetic (railgun), dynamic (cruise missiles) and space (strike from orbit).
The intensification of the US geopolitical rivalry with Russia and China has revived the topic of hypersound as a promising tool capable of providing an advantage in the field of space and missile weapons. The increased interest in these technologies is also due to the concept of inflicting maximum damage on the enemy using conventional (non-nuclear) weapons, which is actually being implemented by NATO countries led by the United States.
Indeed, if the military command has at least a hundred non-nuclear hypersonic vehicles at its disposal that can easily overcome existing air defense and missile defense systems, then this “last argument of kings” will directly affect the strategic balance between nuclear powers. Moreover, a hypersonic missile in the future can destroy elements of strategic nuclear forces both from the air and from space in a period of no more than an hour from the moment the decision is made to the moment it hits the target. This is precisely the ideology embedded in the American military program Prompt Global Strike (prompt global strike).
Is such a program feasible in practice? The arguments “for” and “against” were divided approximately equally. Let's figure it out.
American Prompt Global Strike program
The Prompt Global Strike (PGS) concept was adopted in the 2000s at the initiative of the US Armed Forces command. Its key element is the ability to launch a non-nuclear strike anywhere on the globe within 60 minutes after a decision is made. Work within the framework of this concept is being carried out simultaneously in several directions.
The first direction of PGS, and the most realistic from a technical point of view has become the use of ICBMs with high-precision non-nuclear warheads, including cluster warheads, which are equipped with a set of homing submunitions. To test this area, the sea-based Trident II D5 ICBM was chosen, delivering destructive elements to a maximum range of 11,300 kilometers. Currently, work is underway to reduce the warheads' CEP to values of 60-90 meters.
The second direction of PGS strategic hypersonic cruise missiles (SGKR) have been selected. Within the framework of the adopted concept, the X-51A Waverider (SED-WR) subprogram is implemented. At the initiative of the US Air Force and the support of DARPA, the development of a hypersonic missile has been carried out by Pratt & Whitney and Boeing since 2001.
The first result of the ongoing work should be the appearance by 2020 of a technology demonstrator with an installed hypersonic ramjet engine (scramjet engine). According to experts, the SGKR with this engine can have the following parameters: flight speed M = 7–8, maximum flight range 1300-1800 km, flight altitude 10-30 km.
In May 2007, after a detailed review of the progress of work on the X-51A "WaveRider", military customers approved the missile project. The experimental Boeing X-51A WaveRider is a classic cruise missile with a ventral scramjet and a four-cantilever tail. The materials and thickness of passive thermal protection were selected in accordance with calculated estimates of heat flows. The rocket's nose module is made of tungsten with a silicon coating, which can withstand kinetic heating up to 1500°C. Ceramic tiles developed by Boeing for the Space Shuttle program are used on the bottom surface of the rocket, where temperatures of up to 830°C are expected. The X-51A missile must meet high requirements for stealth (ESR no more than 0.01 m 2). To accelerate the product to a speed corresponding to M = 5, it is planned to install a tandem rocket accelerator using solid fuel.
It is planned to use US strategic aviation aircraft as the main carrier of the SGKR. There is no information yet about how these missiles will be placed - under the wing or inside the fuselage of the “strategist”.
The third direction of PGS are programs to create kinetic weapon systems that hit targets from Earth orbit. The Americans calculated in detail the results of the combat use of a tungsten rod about 6 meters long and 30 cm in diameter, dropped from orbit and striking a ground object at a speed of about 3500 m/s. According to calculations, at the meeting point, energy equivalent to the explosion of 12 tons of trinitrotoluene (TNT) will be released.
The theoretical justification gave rise to the projects of two hypersonic vehicles (Falcon HTV-2 and AHW), which will be launched into orbit by launch vehicles and in combat mode will be able to glide in the atmosphere with an increase in speed when approaching the target. Currently, these developments are at the stage of preliminary design and experimental launches. The main problematic issues so far remain systems based in space (space groups and combat platforms), high-precision target guidance systems and ensuring secrecy of launch into orbit (any launch and orbital objects are opened Russian systems warnings about missile attack and space control). The Americans hope to solve the problem of secrecy after 2019, with the launch of a reusable aviation space system, which will launch a payload into orbit “by airplane”, through two stages - a carrier aircraft (based on a Boeing 747) and an unmanned one. space plane(based on the X-37B prototype).
The fourth direction of PGS is a program to create an unmanned hypersonic reconnaissance aircraft based on the famous Lockheed Martin SR-71 Blackbird.
Lockheed's Skunk Works is currently developing a promising UAV called the SR-72, which should have twice the maximum speed SR-71, reaching values around M = 6.
The development of a hypersonic reconnaissance aircraft is entirely justified. Firstly, the SR-72, due to its colossal speed, will be highly vulnerable to air defense systems. Secondly, it will fill the “gaps” in the operation of satellites, quickly obtaining strategic information and detecting mobile ICBM systems, formations of ships, and groupings of enemy forces in the theater of operations.
Two versions of the SR-72 aircraft are being considered - manned and unmanned, and its use as a attack bomber, a carrier of precision weapons. Most likely, lightweight missiles without a propulsion engine can be used as weapons, since it is not needed when launched at a speed of 6 M. The released weight will likely be used to increase the power of the warhead. Lockheed Martin plans to show a flight prototype of the aircraft in 2023.
Chinese project of a hypersonic aircraft DF-ZF
On April 27, 2016, the American publication Washington Free Beacon, citing sources in the Pentagon, informed the world about the seventh test of the Chinese hypersonic aircraft DZ-ZF. The aircraft was launched from the Taiyuan Satellite Launch Center (Shanxi Province). According to the newspaper, the plane performed maneuvers at speeds from 6,400 to 11,200 km/h, and crashed at a training ground in Western China.
“According to United States intelligence assessments, China plans to use a hypersonic aircraft as a means of delivering nuclear warheads capable of overcoming missile defense systems,” the publication noted. “The DZ-ZF can also be used as a weapon capable of destroying a target anywhere in the world within an hour.”
According to an analysis conducted by US intelligence of the entire series of tests, the hypersonic aircraft were launched with short-range ballistic missiles DF-15 and DF-16 (range up to 1000 km), as well as medium-range DF-21 (range 1800 km). Further testing of launches using the DF-31A ICBM (range 11,200 km) was not ruled out. According to the test program, the following is known: separating from the carrier in the upper layers of the atmosphere, the cone-shaped device accelerated downward and maneuvered along the trajectory of reaching the target.
Despite numerous foreign media publications that the Chinese hypersonic aircraft (HLA) is designed to destroy American aircraft carriers, Chinese military experts were skeptical about such statements. They pointed to the well-known fact that the supersonic speed of the GLA creates a cloud of plasma around the device, which interferes with the operation of the on-board radar when adjusting the course and aiming at such a moving target as an aircraft carrier.
As Colonel Shao Yongling, a professor at the PLA Missile Forces Command College, said in an interview with China Daily: “The ultra-high speed and range make it (the GLA) an excellent means of destroying ground targets. In the future, it can replace intercontinental ballistic missiles.”
According to the report of the relevant commission of the US Congress, the DZ-ZF can be adopted by the PLA in 2020, and its improved long-range version by 2025.
Scientific and technical backlog of Russia - hypersonic aircraft
Hypersonic Tu-2000
In the USSR, work on a hypersonic aircraft began at the Tupolev Design Bureau in the mid-1970s, based on the Tu-144 serial passenger aircraft. Research and design was carried out on an aircraft capable of speeds up to M=6 (TU-260) and a flight range of up to 12,000 km, as well as a hypersonic intercontinental aircraft TU-360. Its flight range was supposed to reach 16,000 km. A project was even prepared for the Tu-244 passenger hypersonic aircraft, designed to fly at an altitude of 28-32 km at a speed of M = 4.5-5.
In February 1986, R&D began in the United States to create the X-30 spaceplane with an air-jet power plant, capable of entering orbit in a single-stage version. The National Aerospace Plane (NASP) project was distinguished by an abundance of new technologies, the key of which was a dual-mode hypersonic ramjet engine, allowing flight at speeds of M=25. According to information received by USSR intelligence, NASP was being developed for civilian and military purposes.
The response to the development of the transatmospheric X-30 (NASP) was the USSR government decrees of January 27 and July 19, 1986 on the creation of an equivalent to the American aerospace aircraft (VKS). On September 1, 1986, the Department of Defense issued technical task for a single-stage reusable aerospace aircraft (MSA). According to this technical assignment, the MVKS was to ensure efficient and economical delivery of cargo into low-Earth orbit, high-speed transatmospheric intercontinental transportation, and the solution of military problems, both in the atmosphere and in near outer space. Of the works submitted to the competition by Tupolev Design Bureau, Yakovlev Design Bureau and NPO Energia, the Tu-2000 project received approval.
As a result of preliminary research under the MVKS program, the power plant was selected based on proven and proven solutions. Existing air-breathing engines (WRE) that used atmospheric air, had temperature restrictions, they were used on aircraft whose speed did not exceed M=3, and rocket engines had to carry large stock fuel on board and were not suitable for long flights in the atmosphere. Therefore, an important decision was made - in order for the aircraft to fly at supersonic speeds and at all altitudes, its engines must have features of both aviation and space technology.
It turned out that the most rational for a hypersonic aircraft is a ramjet engine (ramjet), which has no rotating parts, in combination with a turbojet engine (TRE) for acceleration. It was assumed that liquid hydrogen ramjet engines were most suitable for flights at hypersonic speeds. And the booster engine is a turbojet engine running on either kerosene or liquid hydrogen.
As a result, a combination of an economical turbojet engine operating in the speed range M = 0-2.5, a second engine - a ramjet, accelerating the aircraft to M = 20, and a liquid propellant engine for entering orbit (acceleration to the first escape velocity of 7. 9 km/s) and support for orbital maneuvers.
Due to the complexity of solving a complex of scientific, technical and technological problems for the creation of a single-stage MVKS, the program was divided into two stages: the creation of an experimental hypersonic aircraft with a flight speed of up to M = 5-6, and the development of a prototype of an orbital MVKS, ensuring the conduct of a flight experiment in the entire range flights, up to spacewalk. In addition, at the second stage of the MVKS work, it was planned to create versions of the Tu-2000B space bomber, which was designed as a two-seater aircraft with a flight range of 10,000 km and a take-off weight of 350 tons. Six engines powered by liquid hydrogen were supposed to provide a speed of M=6-8 at an altitude of 30-35 km.
According to specialists from OKB im. A.N. Tupolev, the cost of building one videoconferencing system should have been about 480 million dollars, in 1995 prices (with R&D costs of 5.29 billion dollars). The estimated cost of the launch was to be 13.6 million dollars, with 20 launches per year.
The first time the model of the Tu-2000 aircraft was shown at the Mosaeroshow-92 exhibition. Before work was stopped in 1992, the following were manufactured for the Tu-2000: a wing caisson made of nickel alloy, fuselage elements, cryogenic fuel tanks and composite fuel lines.
Atomic M-19
A long-time “competitor” in strategic aircraft OKB im. Tupolev – Experimental machine-building plant(now EMZ named after Myasishchev) was also involved in the development of a single-stage videoconferencing system as part of the Kholod-2 R&D. The project was called “M-19” and included work on the following topics:
- Topic 19-1. Creation of a flying laboratory with a power plant using liquid hydrogen fuel, development of technology for working with cryogenic fuel;
- Topic 19-2. Design work to determine the appearance of a hypersonic aircraft;
- Topic 19-3. Design and engineering work to determine the appearance of a promising videoconferencing system;
- Topic 19-4. Design and development work to determine the appearance of alternative options for aerospace forces with a nuclear propulsion system.
Work on the promising videoconferencing system was carried out under the direct supervision of General Designer V.M. Myasishchev and General Designer A.D. Tokhuntsa. For execution components R&D plans were approved for joint work with enterprises of the Ministry of Aviation Industry of the USSR, including: TsAGI, CIAM, NIIAS, ITPM and many others, as well as with the Research Institute of the Academy of Sciences and the Ministry of Defense.
The appearance of the single-stage VKS M-19 was determined after studying numerous alternative aerodynamic configurations. In terms of research into the characteristics of a new type of power plant, scramjet models were tested in wind tunnels at speeds corresponding to Mach numbers = 3-12. To assess the effectiveness of the future VKS, mathematical models of the apparatus systems and the combined power plant with a nuclear rocket engine (NRE) were also developed.
The use of a videoconferencing system with a combined nuclear propulsion system implied expanded opportunities for intensive exploration of both near-Earth space, including remote geostationary orbits, and deep space areas, including the Moon and cislunar space.
The presence of a nuclear installation on board the VKS would also make it possible to use it as a powerful energy unit to ensure the functioning of new types of space weapons (beam weapons, beam weapons, means of influencing climate conditions, etc.).
The combined propulsion system (CPS) included:
- Sustaining nuclear rocket engine (NRE) based on a nuclear reactor with radiation protection;
- 10 dual-circuit turbojet engines (DTRDF) with heat exchangers in the internal and external circuits and an afterburner;
- Hypersonic ramjet engines (scramjet engines);
- Two turbochargers to ensure pumping of hydrogen through DTRDF heat exchangers;
- Distribution unit with turbopump units, heat exchangers and pipeline valves, fuel supply control systems.
Hydrogen was used as fuel for the DTRDF and scramjet engines, and it was also the working fluid in the closed circuit of the nuclear propulsion engine.
In its final form, the M-19 concept looked like this: the 500-ton VKS performs takeoff and initial acceleration as a nuclear aircraft with closed-cycle engines, and hydrogen serves as the coolant that transfers heat from the reactor to ten turbojet engines. As it accelerates and gains altitude, hydrogen begins to be supplied to the afterburners of the turbojet engine, and a little later into the direct-flow scramjet engine. Finally, at an altitude of 50 km, at a flight speed of more than 16 Mach, a nuclear-powered rocket engine with a thrust of 320 tf is turned on, which ensured access to a working orbit at an altitude of 185-200 kilometers. With a take-off weight of about 500 tons, the VKS M-19 was supposed to launch a payload weighing about 30-40 tons into a reference orbit with an inclination of 57.3°.
It is necessary to note a little-known fact that when calculating the characteristics of the CDU in turbo-ramjet, rocket-ramjet and hypersonic flight modes, the results of experimental studies and calculations carried out at CIAM, TsAGI and ITPM SB AS USSR were used.
Ajax" - hypersound in a new way
Work on the creation of a hypersonic aircraft was also carried out at the Neva Design Bureau (St. Petersburg), on the basis of which the State Research Enterprise for Hypersonic Speeds was formed (now OJSC NIPGS HC Leninets).
The NIPGS approached the creation of the GLA in a fundamentally new way. The concept of the Ajax GLA was put forward in the late 80s. Vladimir Lvovich Freistadt. Its essence is that the GLA does not have thermal protection (unlike most VKS and GLA). The heat flow that occurs during hypersonic flight is introduced into the HVA to increase its energy resource. Thus, the Ajax GLA was an open aerothermodynamic system, which converted part of the kinetic energy of the hypersonic air flow into chemical and electrical energy, simultaneously solving the issue of airframe cooling. For this purpose, the main components of a chemical heat recovery reactor with a catalyst, located under the airframe, were designed.
The aircraft skin in the most thermally stressed areas had a two-layer shell. Between the layers of the shell there was a catalyst made of heat-resistant material (“nickel sponges”), which was an active cooling subsystem with chemical heat recovery reactors. According to calculations, in all hypersonic flight modes, the temperature of the GLA airframe elements did not exceed 800-850°C.
The GLA includes a ramjet engine with supersonic combustion integrated with the airframe and the main (propulsion) engine - a magnetoplasma chemical engine (MPXE). The MPHD was intended to control the air flow using a magneto-gas-dynamic accelerator (MHD accelerator) and generate electricity using an MHD generator. The generator had a power of up to 100 MW, which was quite enough to power a laser capable of hitting various targets in near-Earth orbits.
It was assumed that the sustainer MPHD would be capable of changing flight speed over a wide range of flight Mach numbers. By braking the hypersonic flow by a magnetic field, optimal conditions were created in the supersonic combustion chamber. During tests at TsAGI, it was revealed that the hydrocarbon fuel created within the framework of the Ajax concept burns several times faster than hydrogen. The MHD accelerator could “accelerate” combustion products, increasing the maximum flight speed to M=25, which guaranteed entry into low-Earth orbit.
The civilian version of the hypersonic aircraft was designed for a flight speed of 6000-12000 km/h, a flight range of up to 19000 km and the carriage of 100 passengers. There is no information about the military developments of the Ajax project.
Russian concept of hypersound – missiles and PAK DA
Work carried out in the USSR and in the first years of its existence new Russia on hypersonic technologies allow us to assert that the original domestic methodology and scientific and technical groundwork have been preserved and used to create Russian HAVs - both in missile and aircraft versions.
In 2004, during the command post exercise “Security 2004”, Russian President V.V. Putin made a statement that still excites the minds of the “public.” “Experiments and some tests were carried out... Soon the Russian Armed Forces will receive combat systems capable of operating at intercontinental distances, at hypersonic speed, with great accuracy, with wide maneuver in height and direction of impact. These complexes will make any missile defense systems, existing or future, unpromising.”.
Some domestic media interpreted this statement to the best of their understanding. For example: “Russia developed the world’s first hypersonic maneuvering missile, which was launched from a Tu-160 strategic bomber in February 2004, when the Security 2004 command post exercises were held...
In fact, during the exercises it was launched ballistic missile RS-18 "Stiletto" with new combat equipment. Instead of a conventional warhead, the RS-18 contained a device capable of changing the altitude and direction of flight, and thereby overcoming any, including American, missile defense. Apparently, the device tested during the Security 2004 exercise was a little-known hypersonic cruise missile (GKR) X-90, developed at the Raduga IKB in the early 1990s.
Judging by the performance characteristics of this missile, the Tu-160 strategic bomber can carry two X-90s. The rest of the characteristics look like this: rocket mass - 15 tons, main engine - scramjet, accelerator - solid propellant rocket engine, flight speed - 4-5 M, launch altitude - 7000 m, flight altitude - 7000-20000 m, launch range 3000-3500 km, number of warheads - 2, warhead power - 200 kt.
In the debate about whether an airplane or a rocket is better, airplanes most often lost, since rockets turned out to be faster and more effective. And the plane became a carrier of cruise missiles capable of hitting targets at a distance of 2500-5000 km. When launching a missile at a target, the strategic bomber did not enter the counter-air defense zone, so making it hypersonic did not make sense.
The “hypersonic competition” between aircraft and missiles is now approaching a new conclusion with a predictable result - missiles are once again ahead of aircraft.
Let's assess the situation. In service long-range aviation, part of the Russian Aerospace Forces, consists of 60 Tu-95MS turboprop aircraft and 16 Tu-160 jet bombers. The service life of the Tu-95MS expires in 5-10 years. The Ministry of Defense decided to increase the number of Tu-160s to 40 units. Work is underway to modernize the Tu-160. Thus, the VKS will soon begin to receive new Tu-160Ms. Tupolev Design Bureau is also the main developer of the promising aviation complex long-range aviation (PAK DA).
Our “probable adversary” is not sitting idly by, he is investing money in the development of the Prompt Global Strike (PGS) concept. The capabilities of the US military budget in terms of funding significantly exceed the capabilities of the Russian budget. The Ministry of Finance and the Ministry of Defense are arguing about the amount of funding for the State Armaments Program for the period until 2025. And we are talking not only about the current costs of purchasing new weapons and military equipment, but also about promising developments, which include PAK DA and GLA technologies.
In the creation of hypersonic ammunition (missiles or projectiles) not everything is clear. Clear advantage hypersound – speed, short approach time to the target, high guarantee of overcoming air defense and missile defense systems. However, there are many problems - the high cost of disposable ammunition, the complexity of control when changing the flight path. These same shortcomings became decisive arguments in the reduction or closure of manned hypersonic programs, that is, hypersonic aircraft.
The problem of the high cost of ammunition can be solved by the presence on board the aircraft of a powerful computer complex for calculating bombing (launch) parameters, which turns conventional bombs and missiles into high-precision weapons. Similar on-board computer systems installed in the warheads of hypersonic missiles make it possible to equate them to the class of strategic high-precision weapons, which, according to PLA military experts, can replace ICBM systems. The presence of strategic-range missiles will call into question the need to maintain long-range aviation, as it has limitations in speed and effectiveness of combat use.
The appearance of hypersonic in the arsenal of any army anti-aircraft missile(GZR) will force strategic aviation to “hide” at airfields, because The maximum distance from which a bomber's cruise missiles can be used will be covered by such GZRs in a few minutes. Increasing the range, accuracy and maneuverability of GZRs will allow them to shoot down enemy ICBMs at any altitude, as well as disrupt a massive raid by strategic bombers before they reach the launch line of cruise missiles. The pilot of the “strategist” may detect the launch of the GZR, but he is unlikely to have time to steer the plane away from defeat.
The development of GLA, which is currently being intensively carried out in developed countries, indicate that a search is underway for a reliable tool (weapon) that can be guaranteed to destroy the enemy’s nuclear arsenal before use nuclear weapons, as the last argument in defending state sovereignty. Hypersonic weapons can also be used against the main centers of political, economic and military power of a state.
Hypersound has not been forgotten in Russia, work is underway to create missile weapons based on this technology (Sarmat ICBM, Rubezh ICBM, X-90), but rely on only one type of weapon (“miracle weapon”, “weapon of retaliation” ") would be, at the very least, incorrect.
There is still no clarity in the creation of PAK DA, since the basic requirements for its purpose and combat use. Existing strategic bombers, as components of Russia's nuclear triad, are gradually losing their importance due to the emergence of new types of weapons, including hypersonic ones.
The course of “containing” Russia, proclaimed as the main task of NATO, is objectively capable of leading to aggression against our country, in which trained and armed modern means Army of the North Atlantic Treaty. In terms of the number of personnel and weapons, NATO is 5–10 times larger than Russia. A “sanitary belt” is being built around Russia, including military bases and missile defense positions. Essentially, NATO activities are described in military terms as operational preparation for a theater of operations (theater of operations). At the same time, the main source of arms supplies remains the United States, as it was in both the First and Second World Wars.
A hypersonic strategic bomber can, within an hour, be anywhere in the world over any military facility (base), from which the supply of resources to troop groups, including those in the “sanitary belt,” is ensured. Lowly vulnerable to missile defense and air defense systems, it can destroy such objects with powerful high-precision non-nuclear weapons. The presence of such a GLA in peacetime will become an additional deterrent for supporters of global military adventures.
The civil GLA can become the technical basis for a breakthrough in the development of intercontinental flights and space technologies. The scientific and technical basis of the Tu-2000, M-19 and Ajax projects is still relevant and can be in demand.
What the future PAK DA will be like - subsonic with SGKR or hypersonic with modified conventional weapons - will be decided by the customers - the Ministry of Defense and the Government of Russia.
“Whoever wins by preliminary calculation before the battle has a lot of chances. Whoever does not win by calculation even before the battle has little chance. Whoever has a lot of chances wins. Those who have little chance do not win. Especially one who has no chance at all.” /Sun Tzu, “The Art of War”/
Military expert Alexey Leonkov
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