An ordinary passenger plane flies at a speed of about 900 km / h. A jet fighter can reach about three times the speed. However, modern engineers from the Russian Federation and other countries of the world are actively developing even more high-speed machines - hypersonic aircraft. What are the specifics of the respective concepts?
Hypersonic Aircraft Criteria
What is a hypersonic airplane? By such, it is customary to understand an apparatus capable of flying at a speed that is many times greater than that for sound. Researchers' approaches to determining its specific indicator vary. A common methodology is used according to which an aircraft should be considered hypersonic if it is several times higher than the speed indicators of the fastest modern supersonic vehicles. Which make about 3-4 thousand km / h. That is, a hypersonic aircraft, if you adhere to this methodology, should have a speed of 6 thousand km / h.
Unmanned and controlled vehicles
Researchers' approaches may also vary in terms of defining criteria for assigning a particular device to airplanes. There is a version that only those machines that are controlled by humans are legitimate. There is a point of view by which an unmanned vehicle can also be considered an airplane. Therefore, some analysts classify the machines of this type into those that are subject to human control, and those that operate autonomously. Such a division can be justified, since unmanned aerial vehicles can have much more impressive technical characteristics, for example, in terms of overload and speed.
At the same time, many researchers consider hypersonic airplanes as a single concept, for which speed is a key indicator. It does not matter whether a person sits at the helm of the device or whether the machine is controlled by a robot - the main thing is that the aircraft should be sufficiently fast.
Take-off - independent or with outside help?
A classification of hypersonic aircraft is widespread, based on classifying them as those that are capable of taking off on their own, or those that involve placement on a more powerful carrier - a rocket or a cargo plane. There is a point of view according to which it is legitimate to attribute to devices of this type mainly those that are capable of taking off independently or with minimal involvement of other types of equipment. However, those researchers who believe that the main criterion characterizing a hypersonic aircraft - speed, should be paramount in any classification. Whether assigning the device to 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 that we are talking about a hypersonic plane.
The main problems of hypersonic solutions
The concepts of hypersonic solutions are many decades old. Throughout the years of developing the appropriate type of apparatus, world engineers have solved a number of significant problems that objectively interfere with putting the release of “hypersound” into the stream - similar to organizing the production of turboprop aircraft.
The main difficulty in the construction of hypersonic aircraft is the creation of an engine that can be sufficiently energy efficient. Another problem is building the necessary thermal protection of the device. The fact is that the speed of a hypersonic airplane in the values that we examined above implies strong hull heating due to friction against the atmosphere.
Today we look at several examples of successful prototypes of aircraft of the corresponding type, the developers of which were able to significantly advance in terms of successfully solving the problems noted. We will now study the most famous world developments regarding the creation of hypersonic aircraft of the type in question.
The fastest aircraft from Boeing
The fastest hypersonic aircraft in the world, according to some experts, is the American Boeing X-43A. So, during the testing of this unit, it was recorded that it reached a speed exceeding 11 thousand km / h. That is about 9.6 times faster than the speed of sound.
Why is the X-43A hypersonic plane especially noteworthy? The characteristics of this aircraft are as follows:
- the maximum speed recorded in the 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 imply the allocation of harmful combustion products.
The X-43A hypersonic aircraft was developed jointly by NASA engineers, as well as Orbical Science Corporation and Minocraft. The aircraft was created about 10 years. 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 to ensure engine thrust.
Development from Orbital Science
Orbital Science, which, as we noted above, took part in the creation of the X-43A, also managed to create its own hypersonic aircraft - X-34.
Its top speed is more than 12 thousand km / h. True, in the course of practical tests it was not achieved - moreover, it was not possible to achieve the indicator shown by the X43-A. The aircraft in question is accelerated when a Pegasus solid-fuel rocket is activated. The X-34 was first tested in 2001. The aircraft under consideration is significantly larger than the apparatus from Boeing - its length is 17.78 m, wingspan - 8.85 m. The maximum altitude of a hypersonic machine from Orbical Science is 75 kilometers.
Aircraft from North American
Another well-known hypersonic aircraft - X-15, released by North American. This analytics apparatus is referred to as experimental.
It is equipped with rocket engines, which gives rise to some experts not to relate it, in fact, to the class of aircraft. However, the presence of rocket engines allows the device, in particular, to perform suborbital flights. So, during one of the tests in this mode, it was tested by pilots. The purpose of the X-15 is to study the specifics of hypersonic flights, evaluate various design decisions, new materials, and control features of similar machines in different layers of the atmosphere. It is noteworthy that the concept of the project was approved back in 1954. X-15 flies at a speed of more than 7 thousand km / h. Its flight range is more than 500 km, altitude exceeds 100 km.
The fastest production aircraft
The hypersonic devices studied by us above are actually classified as research ones. It will be useful to consider some serial samples of aircraft that are close in characteristics to hypersonic or being (according to one or another methodology) them.
Among these machines - the American development of the SR-71. Some researchers are not inclined to attribute this aircraft to hypersonic, since its top speed is about 3.7 thousand km / h. Among its most notable characteristics is its take-off mass, which exceeds 77 tons. The length of the apparatus is more than 23 m, the wingspan is more than 13 m.
One of the fastest military aircraft is the Russian MiG-25. The device can reach speeds of more than 3.3 thousand km / h. The maximum take-off weight of the Russian aircraft is 41 tons.
Thus, in the market for serial solutions that are close in characteristics to hypersonic, the Russian Federation is among the leaders. But what can be said about Russian developments in terms of “classic” hypersonic aircraft? Are engineers from the Russian Federation able to create a solution that is competitive with Boeing and Orbital Scence cars?
Russian hypersonic devices
At the moment, a Russian hypersonic aircraft is under development. But she goes quite actively. This is a Yu-71 aircraft. According to media reports, his first trials were conducted in February 2015 near Orenburg.
It is assumed that the aircraft will be used for military purposes. Thus, if necessary, a hypersonic device will be able to deliver striking means over considerable distances, monitor the territory, and also be involved 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 hypersonic aircraft of Russia in question will be deployed on the Sarmat ballistic missile, which is also at the design stage. Some analysts believe that the U-71 hypersonic apparatus under development is nothing more than a warhead, which will have to be separated from a ballistic missile in the final section of the flight, so that, thanks to the aircraft’s high maneuverability, it can overcome missile defense systems.
Ajax Project
Among the most noteworthy projects related to the development of hypersonic aircraft are Ajax. We will study it in more detail. The Ajax hypersonic aircraft is a conceptual development of Soviet engineers. In the scientific community, talk of her began back in the 80s. Among the most noteworthy features is the presence of a thermal protection system, which is designed to protect the case from overheating. Thus, the developers of the Ajax apparatus have proposed a solution to one of the “hypersonic” problems that we have identified above.
The traditional thermal protection scheme for aircraft involves placing special materials on the hull. The developers of Ajax proposed a different concept, according to which it was supposed not to protect the device from external heating, but to let heat into the machine, while increasing its energy resource. The main competitor of the Soviet apparatus was considered the Aurora hypersonic aircraft, created in the USA. However, due to the fact that designers from the USSR significantly expanded the capabilities of the concept, a wide range of tasks, in particular, research, was entrusted to the new development. We can say that the Ajax is a hypersonic multipurpose aircraft.
Let us consider in more detail the technological innovations proposed by engineers from the USSR.
So, the Soviet developers of Ajax proposed using heat generated as a result of friction of the airplane’s hull against the atmosphere, converting it into useful energy. Technically, this could be realized by placing additional shells on the apparatus. As a result, something like a second building was formed. Its cavity was supposed to be filled with a certain catalyst, for example, a mixture of combustible material and water. The Ajax thermal insulation layer made of solid material was supposed to be replaced by a liquid one, which, on the one hand, was supposed to protect the engine, and on the other hand, it would contribute to a catalytic reaction, which, meanwhile, could be accompanied by an endothermic effect - heat transfer from the outside body parts inward. Theoretically, the cooling of the external parts of the apparatus could be anything. Excessive heat, in turn, was supposed to be used to increase the efficiency of the aircraft engine. Moreover, this technology would allow the generation of free hydrogen due to the reaction of fuel.
At the moment, there is no information available to the general public about the continued development of Ajax, but researchers consider the introduction of Soviet concepts into practice to be very promising.
Chinese hypersonic devices
China becomes the competitor of Russia and the USA in the market of hypersonic solutions. Among the most famous developments of engineers from China is the aircraft WU-14. It is a hypersonic guided glider placed on a ballistic missile.
An ICBM launches an aircraft into space, from where the machine abruptly dives downward, developing hypersonic speed. The Chinese device can be mounted on different ICBMs with a range of 2 to 12 thousand km. It was established that during the tests, the WU-14 was able to develop a speed exceeding 12 thousand km / h, thus turning into the fastest hypersonic aircraft according to some analysts.
However, many researchers believe that the Chinese development is not entirely legitimate to classify as aircraft. So, the version according to which the device should be classified as a warhead is common. And it’s very effective. When flying down at a marked speed, even the most advanced missile defense systems cannot guarantee the interception of the corresponding target.
It may be noted that Russia and the United States are also developing hypersonic devices used for military purposes. At the same time, the Russian concept, according to which it is supposed to create machines of the corresponding type, is significantly different, according to data in some media, from technological principles implemented by the Americans and Chinese. So, developers from the Russian Federation are concentrating efforts in the field of creating aircraft equipped with a ramjet engine capable of starting from the ground. Russia plans to cooperate in this direction with India. Hypersonic devices created according to the Russian concept, according to some analysts, are characterized by lower cost and wider scope.
At the same time, the hypersonic aircraft of Russia, which we mentioned above (Yu-71), suggests, according to some analysts, just placement on ICBMs. If this thesis turns out to be true, then it will be possible to say that engineers from the Russian Federation work immediately in two popular conceptual areas in the construction of hypersonic aircraft.
Summary
So, probably the fastest hypersonic plane in the world, if we talk about aircraft regardless of their classification, it is still the Chinese WU-14. Although you need to understand that real information about him, including those related to tests, can be classified. This is consistent with the principles of Chinese developers, who often at all costs strive to keep their military technology a secret. The speed of the fastest hypersonic aircraft is more than 12 thousand km / h. It is "catching up" with the American development of the X-43A - many experts consider it to be the fastest. Theoretically, the X-43A hypersonic aircraft, 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 possible that they will be close to the parameters of the Chinese aircraft. Russian engineers are also developing hypersonic aircraft that can take off not on the basis of ICBMs, but on their own.
Current projects of researchers from Russia, China and the United States are somehow 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 different countries of the world there are theses that “hypersound”, like atomic technologies, may well be peaceful.
It is up to the emergence of affordable and reliable solutions to organize the mass production of machines of the corresponding type. The use of such devices is possible in a wide range of sectors of economic development. Hypersonic aircraft are likely to find the greatest demand in the space and research industries.
As the production technologies of the corresponding machines become cheaper, transport businesses may begin to show interest in investing in such projects. Industrial corporations, providers of various services may begin to consider "hypersound" as a tool to increase the competitiveness of business in terms of organizing international communications.