# Hypersonic "Object 4202" and its test

"Object 4202" is a symbol of the newest Russian project in the field of modern military hypersonic aircraft (LA). According to authoritative foreign think tanks, its successful implementation can level out the advantages in the field of strategic armaments that the US intends to gain over Russia as a result of the deployment of a global missile defense system.

## How are airspeeds classified by flight speed

LA in terms of its speed characteristics are divided into subsonic, supersonic and hypersonic. At the same time, their flight speeds are usually expressed in the form of dimensionless quantities, a multiple of the so-called. The Mach number, named after the Austrian physicist Ernst Mach, and denoted by the Latin letter M. The Mach number is a dimensionless quantity and can be simplified as a ratio of the speed of the aircraft to the speed of sound in the air at a given altitude. Therefore, the speed of an aircraft in 1 M (or M = 1) means that it flies with the speed of sound. It should be remembered that the speed of sound decreases with altitude, therefore different values, expressed in km / h, will correspond to the value of 1 M at different heights. So, at the ground speed 1 M corresponds to a value of 1224 km / h, and at an altitude of 11 km - 1062 km / h.

The speeds of supersonic aircraft can not exceed 5 M (or M = 5), and hypersonic ones fly just above 5 M. They can also maneuver using aerodynamic forces arising during flight, and also plan for distances, Much larger than at pre-hypersonic speeds.

## The physical grounds for distinguishing hypersonic aircraft

The 5 M boundary between supersonic and hypersonic aircraft is not chosen by chance. The point is that when this speed is reached, the nature of the flow of aerodynamic and gas-dynamic processes, respectively, near the hull of the aircraft and inside its jet engine, substantially changes. First, the boundary layer of air flowing around the aircraft at a speed of 5 M is heated to a temperature of several thousand degrees (especially in front of the front of the aircraft), and the molecules of the gases forming the air composition decay into ions (dissociate). The physico-chemical properties of such an ionized gas differ substantially from the properties of ordinary air, it tends to enter into chemical reactions with the surface of the aircraft, intense convective and radiative heat exchange occurs between it and the flowing stream. Therefore, the thermal protection of the aircraft should be no worse than that of the American "space shuttle" or the Soviet "Buran".

In addition, hypersonic aircraft need a very special design of a jet engine, which is unlike any of the known types. The fact is that in the known aircraft engines of supersonic aircraft, the speed of the flow of air withdrawn from the atmosphere during the formation of the fuel-air mixture inevitably decreases to subsonic (otherwise it is impossible to enter the required amount of fuel into the air). In a hypersonic aircraft, such a reduction in the air current speed is unacceptable - due to the law of energy conversion this will cause such an overheating of the engine design elements that any known material can not cope with.

## Design Features

The hypersonic aircraft engine (in the simplest version) is similar to two articulated funnels, one of which serves as an air intake (the narrow part is a kind of compressor combined with a fuel injector, and also serves as a combustion chamber), and the second funnel is a nozzle for the exit of burned gases that create Traction. Such an engine can be placed only under the fuselage of the aircraft, which creates a certain appearance of hypersonic devices.

However, such an engine can not operate at speeds less than 5-6 M, since the compressed stream simply does not warm up to the temperatures required for complete combustion of the fuel. Therefore, the most realistic way to accelerate the hypersonic aircraft to the required engine start-up speed (at least at the present stage) is the use of a detonating rocket-accelerator as a first stage, sometimes in combination with an accelerator aircraft. The photo below shows an American hypersonic aircraft X-52, anchored under the wing of the strategic bomber B-52.

## The state of work on hypersonic aircraft in the United States

The United States has long begun the development of new types of offensive weapons. First of all, this is hypersonic aircraft. So, within the framework of the DARPA Falcon Project, a missile glider, designated HTV-2, is being developed, as well as projects of hypersonic vehicles from Boeing Corporation (X-43, X-51) equipped with straight-flow air-jet engines similar to those shown in the photo above. They are capable of carrying warheads weighing up to 450 kg, which can be both nuclear munitions and volumetric bombs, adjacent to them in power, capable of destroying the enemy's protected CPs.

The Boeing X-51 project will be able to reach speeds up to 6400 km / h. For the first time this device was launched in May 2010. In total, there were two unsuccessful starts, which resulted in the destruction of the glider. After separation from the carrier aircraft, the device is accelerated by an additional booster, executed on the basis of a military-tactical missile. Only after reaching a speed of 5400 km / h is included the jet engine of the aircraft itself, which accelerates it to the cruising speed.

## What we lost from the Soviet hypersonic developments

Of course, Russia had to parry such a threat. Today, relevant Soviet developments are brought to mind. In the 80s of the last century, we had advanced developments in this field and even a finished product - the X-90 rocketplane of the project "Gala". According to experts, the X-90 was successfully launched from an aircraft specially adapted for this purpose, and accelerated to 5,400 km / h, which is the boundary of hypersound. But then came the "blessed liberals of the 1990s," and the project was closed.

## The Russian response to "Washington"

Recently, the famous British military research center Janes Information Group published information that in February of last year in Russia at the Dombarovsky test range (Orenburg region) flight tests of hypersonic aircraft under the symbol Yu-71 (Yu-71) were carried out. Object 4202, which, according to the same center, is a generalized symbol for all Russian hypersonic developments, is part of our missile program.

But formally it is ordered from the industry not by the military department, but by the Federal Space Agency of the Russian Federation, which in modern conditions is not a superfluous "cover" of this work. The main performer of the ROC on the subject "Object 4202" is "NPO mechanical engineering" from the Reutov suburb near Moscow (the former rocket design bureau of the designer Vladimir Chelomey, who was the main developer of cruise missiles and medium-range ballistic missiles in the USSR).

By the way, the site of this enterprise posted information that in the late 50-ies of the last century in the KB was created LA MP-1, capable of maneuvering in the atmosphere with the help of aerodynamic controls with hypersonic speeds. Its successful launch was carried out in 1961! So the subject "Object 4202" has a long history.

## Perspectives of the Russian "hypersound"

It is known from a number of sources that since the beginning of the 2000s, Russia has begun work on "military hypersound" and is going to install the Yu-71 product on the promising ballistic missile "Sarmat". The new Russian hypersonic object 4202 is capable of accelerating to a speed of 11,000 km / h and can carry a conventional or nuclear warhead. At such giant speeds, the device can maneuver, being in the atmosphere at altitudes of 40 to 50 km. Therefore, it can not be intercepted by any of the most advanced missile defense systems.

And although the combat blocks of modern intercontinental ballistic missiles also reach hypersonic speeds in flight, their trajectories are amenable to calculation, and hence, to possible interception by missile defense. The product U-71 (object 4202) is capable, unlike them, of maneuvering along a complex unpredictable trajectory, changing the course and height, so that it is practically impossible to intercept it.

At the same time, there are reasons to assume that the first tests of object 4202 were carried out in 2004. It was then that Deputy Chief of the General Staff of the Armed Forces of Russia Baluyevsky reported at a press conference on testing hypersonic aircraft, maneuvering at the rate and height.

## "Object 4202": to the shores of America on hypersound

The American press reacted to the tests of the Russian hypersonic glider. Many newspapers openly talked about how the American strategy of a lightning-fast global strike had a serious competitor. If the work on the project "Object 4202" is successfully completed, then in 10 years, Russia will receive a serious "trump card" in the negotiations with the United States. The fact is that in the presence of hypersonic aircraft, it can be guaranteed to hit any target in the US with only one missile. For example, the same "Sarmat", which will be installed LA, created under the project "Object 4202". Hypersonic in flight speed plus maneuvering capabilities of a new type of aircraft - these are the new qualities of this weapon, which, perhaps, will make senseless the colossal resources of resources for the creation of American missile defense systems.