The development of a second-generation supersonic passenger aircraft, abbreviated as SPS-2, is entering its final phase. The first flight of the Tu-244 is expected by 2025. The new Russian commercial airliner will be structurally different from the Soviet Tu-144 in terms of characteristics, flight range, comfort, spaciousness, size, engine power, and avionics. Its supersonic speed of Mach 2 will remain the same as that of its predecessor Tu-144LL Moskva; this is still the best indicator in the world in heavy civil aircraft construction. At an altitude of 20 km, the routes are free.

A limitation for aircraft designers and developers may be the length of the 1st class runway; at least 3 km is required. Not all airports around the world and the country have such concrete strips. There can be no illusions that the best aircraft will not be in demand in Western countries, which are more interested in selling their European Airbus and American Boeing, flying at a speed of 700 - 900 km/h, 2.5-3 times slower. You will have to rely only on the needs of Russia and the BRICS, as well as on wealthy customers who can afford such aircraft.

Project objectives

The first Tu-244 model is expected to have proven NK-32 engines, the same as the Tu-160M2 strategic bomber upgraded on November 16, 2017. The very first development of SPS-2 began too early, in 1973, thanks to the developments of Soviet military designers of the 1950s, who were 50 years ahead of their time. At that time there were not yet high-quality composite materials to be used in large quantities, and the power plants had insufficient traction. In the 1960s there were engines with 20-ton thrust, in the 1970s with 25-ton, and now 32-ton engines are used.

Aircraft designers are given 2 main tasks:

Flight range – 9,200 km.

Reduced fuel consumption for this class of equipment.

The first and second problems can be solved following the example of the Tu-160 and Tu-22M3, using variable wing sweep, making the aircraft multi-mode. You can analyze Chernyakov’s closed projects T-4 and T-4MS, study Myasishchev’s developments on modifications of the M-50, ingenious and fantastic then, more suitable today. The Tupolev Design Bureau has everything for this; materials from all the leading design bureaus of the USSR involved in heavy weapons are collected here. strategic aviation, on the basis of which the world's best military long-range aircraft, the Tu-22M3M and Tu-160M2, were created.

Advantages of jet aircraft

Advantage jet plane- speed. This guarantees a comfortable flight and reduces the distance in time. Spending three times less hours in a seat means that passengers feel good, for example, on the Vladivostok – Kaliningrad flight. Business time is saved. Using the services of the Tu-244 airliner, you can spend 1 day more on vacation, and upon arrival, immediately go to work without fatigue. It is also important to receive moral satisfaction for our citizens from the prestige of the Tu-244 and to experience pride in Russia. Release of civilians jet aircraft from the military-industrial complex of the Russian Federation - more important than the self-sufficiency of the country's defense enterprises, this is a commercial orientation, jobs, a guarantee of stability and the accumulation of profits in tough market conditions.

Disadvantages of high-speed passenger airliners

In the Tupolev Design Bureau in the 1960s they noticed that the creation of a civilian supersonic passenger airliner according to military principles it will not work due to the requirements for comfort and safety. We began to study the experience of the USA, France and England in this regard; what was considered the best, then, according to the plan of the chief designer Alexei Andreevich Tupolev, went into work. The disadvantages of the first Tu-144 and Concorde include high fuel consumption, engine noise, sound booms, and the amount of harmful emissions into the atmosphere.

The main disadvantage of the Tu-244 is the commercial, military and political institutions of the West, because their Concordes flew off in 2003, and there are no new plans, because our aircraft manufacturing paths diverge. Explanation for this: firstly, NATO does not need strategic supersonic aviation, because Their power is based on an aircraft-carrying ocean-going fleet, and it is enough to deliver nuclear bombs and missiles by aircraft with a range of 1.5 km (fighters) from military bases scattered around the world, which is why military projects of this class are not in great demand in the West. Also, the rather high cost of the flight sharply narrows the potential market segment for these aircraft, so mass production is out of the question. However, a simultaneous order for the military and passenger transportation, this is exactly what can give a serious boost to supersonic passenger aviation.

What will the Tu-244 be like in terms of flight characteristics?

The design was delayed, the Tu-144 in the 1968 configuration reached its first design characteristics by the mid-1970s. Work on its improvement has been going on since 1992 - the beginning of the Tu-244 project; 25 years have passed since then; it will take another 10 to finish what we started. It is clearly seen that the involvement of the USA, England and France in the development of the Tu-244 program with the collapse of the USSR did not which did not lead to anything good, as in all similar cases in the former USSR. Only the collection of scientific data from the Tu-144LL for the NASA military space program and the inhibition of our enterprises in the development.

Today there are many variants of Tu-244 projects. No one can say for sure what the plane itself will be like. Unofficial sources are disseminating ambiguous information. The characteristics described below are conditional, compiled on the basis of current capabilities. Characteristics: length 88.7 m; wingspan 54.77 m, area 1,200 sq.m., and aspect ratio 2.5 m; wing sweep along the edge - 75 degrees at the center section, 35 degrees at the console; fuselage width 3.9 m, height 4.1 m, luggage compartment 32 sq.m.; take-off weight 350 tons, including fuel 178 tons; NK-32 engines – 4 units; cruising speed 2.05 M; range 10 thousand km; Max. altitude 20 km.

Design of Tu-244

Let us imagine a trapezoidal wing and the complex deformation of its middle trapezoid. Aileron control in trim, roll and pitch. At the leading edge, the toes are deflected mechanically. The wing structure is divided into parts: front, middle and console. The middle and console parts have multi-spar and multi-rib power circuits, but there are no ribs in the front part. The vertical tail is the same as the wing structure and the two-section rudder guide.

Fuselage with a pressurized cabin, nose and tail compartments - the size will be selected to order based on the number of passenger seats. For 250 and 320 passengers, a fuselage diameter of 3.9 to 4.1 m is suitable. The cabin will be divided into classes, 1st, 2nd and 3rd. In terms of comfort, the Tu-244 will be at the level of the latest modification of the Tu-204. The plane is equipped with a cargo compartment. There are four pilots, their seats with catapults (in Russian), shooting upward. Everything on board is newly automated and subordinated to central program control.

The Tu-244 may lose the deflectable nose, similar to the Tu-144LL, due to the development of the latest optical-electronic equipment and the ability to deflect controlled thrust vectors in modern domestic power plants. In areas of maximum load, titanium alloy VT-64 can be used in the wheel area. The bow strut may remain the same, but there will definitely be 3 new main supports for the concrete strip, designed for high loads. Navigation and flight equipment will comply with the meteorological minimum according to the international classification IIIA ICAO.

The exploration of the sky has been an unattainable dream for mankind for many centuries. After the expanses were finally conquered, the aircraft became more and more sophisticated and durable. A significant achievement in this field was the invention of supersonic military and passenger aircraft. One of these airliners was the Tu-244, the features and characteristics of which we will consider further. Unfortunately, this project did not develop into mass production, like most similar developments. Funds are currently being sought to resume development of this project or similar aircraft.

How did it all begin?

Aviation began to develop rapidly after the Second World War. Various projects of aircraft with jet engines were developed, which were supposed to replace conventional power units. The important point in creating supersonic airliners was not reaching the speed of sound, but overcoming this barrier, since aerodynamic laws change at such speeds.

Similar technologies began to be used en masse in the fifties of the last century. Among the serial modifications are domestic MiGs, American North American fighters, Delta Daggers, French Concordes and many others. In passenger aviation, the introduction of supersonic speeds was much slower. The Tu-244 is an aircraft that could not only compete in this industry, but become a world leader in it.

Development and creation

The first experimental civil aircraft capable of breaking the sound barrier appeared in the second half of the sixties of the 20th century. From then until now, only two models have been put into mass production: the Tu-144 and the French Concorde. The airliners were typical aircraft for ultra-long flights. The operation of these machines ceased to be relevant in two thousand and three. Currently, supersonic airliners are not used to transport passengers.

There have been attempts to create new modifications of civilian jet airliners, but most of them remained under development or were closed altogether. Such long-term projects include the Tu-244 supersonic passenger aircraft.

It was supposed to replace its predecessor and have improved characteristics borrowed from prototypes - Concorde and some American aircraft. The project was fully developed by the Tupolev design bureau; in 1973, the aircraft under development received the name Tu-244.

Purpose

The main objective of the project being developed was the creation of a supersonic jet aircraft capable of transporting passengers safely, quickly and over long distances. Moreover, the device had to be significantly superior in all respects to conventional jet aircraft. The designers placed a special emphasis on speed.

In other aspects supersonic aircraft inferior to their brothers. Firstly, transportation was not economically profitable. Secondly, flight safety was lower. By the way, serial production and use in civil aviation the predecessor of the Tu-244 was discontinued precisely for the second reason. During the first year of operation, the Tu-144 suffered several accidents that led to the death of the crew. The new project was supposed to eliminate the shortcomings.

Tu-244 (aircraft): technical characteristics

The final model of the airliner in question was supposed to have the following tactical and technical indicators:

  1. The crew piloting the aircraft includes three pilots.
  2. Passenger capacity varied from 250 to 300 people.
  3. The estimated cruising speed is 2175 kilometers per hour, which is twice the sound barrier.
  4. Power plants - four motors with turbine fans.
  5. The flight range is from seven to nine and a half thousand kilometers.
  6. The carrying capacity is three hundred tons.
  7. Length / height - 88 / 15 meters.
  8. Working surface area - 965 sq. m.
  9. The wingspan is forty-five meters.

If we compare the speed indicator, the projected Tu-244 passenger aircraft, the history of which is quite interesting, has become a little slower than its direct competitors. However, due to this, the designers wanted to increase capacity and increase the economic benefits of operating the machine.

Future prospects

The development of a new project, the result of which was supposed to be a supersonic passenger aircraft Tu-244, dragged on for many years. A lot of changes and improvements were made to the design. However, even after the collapse of the USSR, the Tupolev Design Bureau continued to work in given direction. In 1993, detailed information about the project was even presented.

Nevertheless, the economic crisis of the nineties had a negative impact on this area. There was no official message about the closure of developments, nor any active actions. The project was on the verge of being frozen. Specialists from the United States are joining the work, negotiations with whom have been ongoing for a long time. To continue research, two aircraft of the one hundred and forty-fourth series were converted into flying laboratories.

What's next?

The supersonic Tu-244 (the aircraft whose photo is presented below) unexpectedly disappeared from the design documentation as an object of research. It was adopted in two thousand and twelve and assumed that the first hundred units of passenger airliners would enter service no later than 2025. This leapfrog with documentation raised a number of questions and misunderstandings. In addition, several other interesting and promising developments have disappeared from this program.

This prospect was seen in a negative way. Facts indicated that the project was frozen or closed completely. However, there was no official confirmation or denial about this. Given the instability of the economy, a lot of assumptions can be made in a subjective configuration, but the facts speak for themselves.

Today's realities: Tu-244 (aircraft)

History of creation of this aircraft was stated above. How are things going now? Considering all that has been said, it can be assumed that the project in question is currently at least hanging in the air, if not completely covered. There is no official submission of a statement about the fate of the development, as well as the reasons for the reduction and suspension of the project. It is quite possible that the main problem is insufficient funding, economic inadequacy or obsolescence. Alternatively, all three of these factors together may be present.

Not so long ago (2014), information leaked in the media about the possible resumption of the Tu-244 project. However official version Again, no action was taken on this issue. For the sake of objectivity, it is worth noting that foreign developments of passenger supersonic airliners are also far from complete, many of them are closed or are under big question. I would like to believe that this grandiose machine will be built according to all modern standards in the near future.

A little about the predecessor

The development of TU-144 by decision of the Council of Ministers of the Soviet Union began in nineteen sixty-nine. Construction of a supersonic civil aircraft started at MMZ "Experience". The estimated flight range of the airliner should be three and a half thousand kilometers. To improve aerodynamics, the aircraft received a modified wing planform and an increased area.

The length of the fuselage is designed to accommodate internal accommodation of one hundred and fifty passengers. Two pairs of engines were placed under each wing. The jet aircraft made its first flight in 1971. The factory test program included about two hundred and thirty flights.

Comparative characteristics

The supersonic Tu-244 is an aircraft whose dimensions are somewhat larger than those of its predecessor. It has distinctive parameters in other tactical and technical meanings. For comparison, consider the performance of the Tu-144 airliner:

  • crew - four people;
  • capacity - one and a half hundred passengers;
  • length / height - 67 / 12.5 meters;
  • thrust with afterburner - 17,500 kg/s;
  • maximum weight - one hundred eighty tons;
  • cruising speed is 2,200 kilometers per hour;
  • practical ceiling - eighteen thousand meters;
  • maximum range - six and a half thousand kilometers.

The main external difference between the new aircraft (Tu-244) and its predecessor was supposed to be a change in the design of the curved nose.

The cardinal feature of the two hundred and forty-fourth project from its prototype under the symbol “144” is the absence of a downward deflecting nose. The cabin glazing is minimally equipped. This solution is designed to provide the necessary visibility during the flight, and takeoff and landing, regardless of weather conditions, are controlled by an electronic vision optics unit.

It is worth noting that modern environmental requirements for civil airliners significantly impede the creation of a supersonic aircraft of this class, since its operation a priori becomes economically detrimental. Developments have been undertaken to create a supersonic business class aircraft capable of breaking the supersonic barrier. However, the Tu-444 project was also suspended. Its advantages over its competitors are its relative low cost compared to the Tu-244 airliner, as well as the solution to technical issues related to environmental requirements for modern aircraft. For reference: the supersonic airliner in question was presented to the general public in France (1993, Le Bourget air show).

Finally

If all Soviet initiatives in aviation had been finalized and implemented, it is quite possible that this industry would have made a huge leap forward. However, economic, political and other problems significantly slow down this process. One of the most prominent representatives in the world of supersonic civil aviation was to be the Tu-244 airliner. Unfortunately, for a number of reasons, the project is still in development or in a “suspended” state. I would like to hope that there will be people who will finance the project, and this will ultimately lead to the creation of not only the fastest passenger aircraft, but also the transport of the future, characterized by efficiency, capacity and safety.

On December 31, 1968, the world's first supersonic passenger aircraft, the Tu-144, made a test flight. Three years later, in the summer of 1971, he made an incredible impression on the organizers and guests of the International Aviation Exhibition in Paris. To demonstrate the capabilities of the “Soviet bird,” the developers sent the plane from Moscow at 9 a.m. and at the same time, at 9 a.m., it landed in the capital of Bulgaria.

Design of the supersonic aircraft Tu - 144.

Tu-144 is a Soviet supersonic aircraft developed by the Tupolev Design Bureau in the 1960s. Along with Concorde, it is one of two supersonic airliners that have ever been used by airlines for commercial transport.
In the 60s, projects to create a passenger supersonic aircraft with a maximum speed of 2500-3000 km/h and a flight range of at least 6-8 thousand km were actively discussed in aviation circles in the USA, Great Britain, France and the USSR. In November 1962, France and Great Britain signed an agreement on the joint development and construction of Concorde (Concord).

Creators of a supersonic aircraft.

In the Soviet Union, the design bureau of academician Andrei Tupolev was involved in the creation of a supersonic aircraft. At a preliminary meeting of the Design Bureau in January 1963, Tupolev stated:
“Reflecting on the future of air transportation of people from one continent to another, you come to a clear conclusion: supersonic airliners are undoubtedly needed, and I have no doubt that they will come into use…”
The academician's son, Alexey Tupolev, was appointed as the lead designer of the project. More than a thousand specialists from other organizations worked closely with his design bureau. The creation was preceded by extensive theoretical and experimental work, which included numerous tests in wind tunnels and natural conditions during analogue flights.

Concorde and Tu-144.

The developers had to rack their brains to find the optimal design for the machine. The speed of the designed airliner is fundamentally important - 2500 or 3000 km/h. The Americans, having learned that the Concorde is designed for 2500 km/h, announced that just six months later they would release their passenger Boeing 2707, made of steel and titanium. Only these materials could withstand the heating of the structure when in contact with air flow at speeds of 3000 km/h and above without destructive consequences. However, solid steel and titanium structures still have to undergo serious technological and operational testing. This will take a lot of time, and Tupolev decides to build a supersonic aircraft from duralumin, designed for a speed of 2500 km/h. The American Boeing project was subsequently completely closed.
In June 1965, the model was shown at the annual Paris Air Show. Concorde and Tu-144 turned out to be strikingly similar to each other. Soviet designers said - nothing surprising: the general shape is determined by the laws of aerodynamics and the requirements for a certain type of machine.

Supersonic aircraft wing shape.

But what should the wing shape be? We settled on a thin delta wing with the front edge shaped like the letter “8”. The tailless design - inevitable with such a design of the load-bearing plane - made the supersonic airliner stable and well controllable in all flight modes. Four engines were located under the fuselage, closer to the axis. The fuel is placed in coffered wing tanks. The trim tanks, located in the rear fuselage and wing swells, are designed to change the position of the center of gravity during the transition from subsonic to supersonic flight speeds. The nose was made sharp and smooth. But how can pilots have forward visibility in this case? They found a solution - the “bowing nose.” The fuselage had a circular cross-section and had a cockpit nose cone that tilted downward at an angle of 12 degrees during takeoff and 17 degrees during landing.

A supersonic plane takes to the sky.

The first supersonic aircraft took to the skies on the last day of 1968. The car was flown by test pilot E. Elyan. As a passenger aircraft, it was the first in the world to overcome the speed of sound in early June 1969, at an altitude of 11 kilometers. The supersonic aircraft reached the second speed of sound (2M) in mid-1970, at an altitude of 16.3 kilometers. The supersonic aircraft incorporates many design and technical innovations. Here I would like to note such a solution as the front horizontal tail. When using PGO, flight maneuverability was improved and speed was reduced during landing. The domestic supersonic aircraft could be operated from two dozen airports, while the French-English Concorde, having a high landing speed, could land only at a certified airport. The designers of the Tupolev Design Bureau did a colossal job. Take, for example, full-scale tests of a wing. They took place on a flying laboratory - the MiG-21I, modified specifically for testing the design and equipment of the wing of the future supersonic aircraft.

Development and modification.

Work on the development of the basic design of "044" went in two directions: the creation of a new economical afterburning turbojet engine of the RD-36-51 type and a significant improvement in the aerodynamics and design of the supersonic aircraft. The result of this was to meet the requirements for supersonic flight range. The decision of the commission of the USSR Council of Ministers on the version of the supersonic aircraft with the RD-36-51 was made in 1969. At the same time, at the proposal of the MAP - MGA, a decision is made, before the creation of the RD-36-51 and their installation on a supersonic aircraft, on the construction of six supersonic aircraft with NK-144A with reduced specific fuel consumption. The design of serial supersonic aircraft with the NK-144A was supposed to be significantly modernized, significant changes in aerodynamics would be made, obtaining a Kmax of more than 8 in supersonic cruising mode. This modernization was supposed to ensure the fulfillment of the requirements of the first stage in terms of range (4000-4500 km), and in the future it was planned to transition to series on RD-36-51.

Construction of a modernized supersonic aircraft.

Construction of the pre-production modernized Tu-144 (“004”) began at MMZ “Experience” in 1968. According to calculated data with NK-144 engines (Cp = 2.01), the estimated supersonic range was supposed to be 3275 km, and with NK-144A ( Average = 1.91) exceed 3500 km. In order to improve the aerodynamic characteristics in cruising mode M = 2.2, the wing planform was changed (the sweep of the floating part along the leading edge was reduced to 76°, and the base one was increased to 57°), the shape of the wing became closer to the "Gothic". Compared to the "044", the wing area increased, a more intense conical twist of the end parts of the wing was introduced. However, the most important innovation in the aerodynamics of the wing was the change in the middle part of the wing, which ensured self-balancing in cruising mode with minimal losses quality, taking into account optimization for flight deformations of the wing in this mode. The length of the fuselage was increased to accommodate 150 passengers, and the shape of the nose was improved, which also had a positive effect on aerodynamics.

Unlike "044", each pair of engines in paired engine nacelles with air intakes was moved apart, freeing the lower part of the fuselage from them, unloading it from increased temperature and vibration loads, while changing the lower surface of the wing in the place of the calculated area of ​​flow compression, increasing the gap between the lower surface wing and the upper surface of the air intake - all this made it possible to more intensively use the effect of compressing the flow at the entrance to the air intakes on the Kmax than was possible to achieve on the "044". The new layout of the engine nacelles required changes to the chassis: the main landing gear was placed under the engine nacelles, with them retracted inside between the air ducts of the engines, they switched to an eight-wheeled trolley, and the scheme for retracting the nose landing gear also changed. An important difference between “004” and “044” was the introduction of a front multi-section destabilizer wing retractable in flight, which extended from the fuselage during takeoff and landing modes, and made it possible to ensure the required balancing when the elevons-flaps were deflected. Design improvements, an increase in payload and fuel reserves led to an increase in take-off weight, which exceeded 190 tons (for "044" - 150 tons).

Pre-production Tu-144.

Construction of pre-production supersonic aircraft No. 01-1 (tail No. 77101) was completed at the beginning of 1971, and made its first flight on June 1, 1971. According to the factory test program, the vehicle completed 231 flights, lasting 338 hours, of which 55 hours flew at supersonic speed. On this machine, complex issues of interaction of the power plant in various flight modes were worked out. On September 20, 1972, the car flew along the Moscow-Tashkent highway, while the route was covered in 1 hour 50 minutes, the cruising speed during the flight reached 2500 km/h. The pre-production vehicle became the basis for the deployment of serial production at the Voronezh Aviation Plant (VAZ), which, by decision of the government, was entrusted with the development of a supersonic aircraft in a series.

First flight of the production Tu-144.

The first flight of serial supersonic aircraft No. 01-2 (tail No. 77102) with NK-144A engines took place on March 20, 1972. In the series, based on the results of tests of the pre-production vehicle, the aerodynamics of the wing were adjusted and its area was once again slightly increased. The take-off weight in the series reached 195 tons. By the time of operational testing of production vehicles, the specific fuel consumption of the NK-144A was intended to be increased to 1.65-1.67 kg/kgf/hour by optimizing the engine nozzle, and subsequently to 1.57 kg/kgf/hour, while the flight range should was increased to 3855-4250 km and 4550 km, respectively. In reality, they were able to achieve by 1977 during testing and development of the Tu-144 and NK-144A series Av = 1.81 kg/kgf hour in cruising supersonic thrust mode 5000 kgf, Av = 1.65 kg/kgf hour in takeoff afterburner thrust mode 20000 kgf, Av = 0.92 kg/kgf hour in the cruising subsonic mode of thrust 3000 kgf and in the maximum afterburning mode in the transonic mode we received 11800 kgf. A fragment of a supersonic aircraft.

First stage of testing.

In a short period of time, in strict accordance with the program, 395 flights were completed with a total flight time of 739 hours, including more than 430 hours in supersonic modes.

Second stage of testing.

At the second stage of operational testing, in accordance with the joint order of the ministers of aviation industry and civil aviation dated September 13, 1977 No. 149-223, a more active connection of civil aviation facilities and services took place. A new testing commission was formed, headed by Deputy Minister of Civil Aviation B.D. Rude. By decision of the commission, then confirmed by a joint order dated September 30 - October 5, 1977, crews were appointed to conduct operational tests:
First crew: pilots B.F. Kuznetsov (Moscow State Transport Administration), S.T. Agapov (ZhLIiDB), navigator S.P. Khramov (MTU GA), flight engineers Yu.N. Avaev (MTU GA), Yu.T. Seliverstov (ZhLIiDB), leading engineer S.P. Avakimov (ZhLIiDB).
Second crew: pilots V.P. Voronin (MSU GA), I.K. Vedernikov (ZhLIiDB), navigator A.A. Senyuk (MTU GA), flight engineers E.A. Trebuntsov (MTU GA) and V.V. Solomatin (ZhLIiDB), leading engineer V.V. Isaev (GosNIIGA).
Third crew: pilots M.S. Kuznetsov (GosNIIGA), G.V. Voronchenko (ZhLIiDB), navigator V.V. Vyazigin (GosNIIGA), flight engineers M.P. Isaev (MTU GA), V.V. Solomatin (ZhLIiDB), leading engineer V.N. Poklad (ZhLIiDB).
Fourth crew: pilots N.I. Yurskov (GosNIIGA), V.A. Sevankaev (ZhLIiDB), navigator Yu.A. Vasiliev (GosNIIGA), flight engineer V.L. Venediktov (GosNIIGA), leading engineer I.S. Mayboroda (GosNIIGA).

Before the start of testing, a lot of work was done to review all the materials received in order to use them “for credit” for meeting specific requirements. However, despite this, some civil aviation specialists insisted on implementing the “Operational Test Program for Supersonic Aircraft,” developed at GosNIIGA back in 1975 under the leadership of leading engineer A.M. Teteryukov. This program essentially required the repetition of previously completed flights in the amount of 750 flights (1200 flight hours) on MGA routes.
The total volume of operational flights and tests for both stages will be 445 flights with 835 flight hours, of which 475 hours are in supersonic modes. 128 paired flights were performed on the Moscow-Alma-Ata route.

The final stage.

The final stage of testing was not stressful from a technical point of view. Rhythmic work according to schedule was ensured without serious failures or major defects. The engineering and technical crews “had fun” by assessing household equipment in preparation for passenger transportation. Flight attendants and relevant specialists from GosNIIGA, who were involved in the tests, began to conduct ground training to develop the technology for servicing passengers in flight. The so-called “pranks” and two technical flights with passengers. The “raffle” was held on October 16, 1977 with a complete simulation of the cycle of ticket check-in, baggage check-in, passenger boarding, flight of actual duration, passenger disembarkation, baggage check-in at the destination airport. There was no end to the “passengers” (the best workers of OKB, ZhLIiDB, GosNIIGA and other organizations). The diet during the “flight” was at the highest level, since it was based on the first class menu, everyone enjoyed it very much. The “raffle” made it possible to clarify many important elements and details of passenger service. On October 20 and 21, 1977, two technical flights were carried out along the Moscow-Alma-Ata highway with passengers. The first passengers were employees of many organizations that were directly involved in the creation and testing of the supersonic aircraft. Today it is even difficult to imagine the atmosphere on board: there was a feeling of joy and pride, great hope for development against the backdrop of first-class service, to which technical people are absolutely not accustomed. On the first flights, all the heads of the parent institutes and organizations were on board.

The road is open for passenger traffic.

The technical flights took place without serious problems and showed the full readiness of the supersonic aircraft and all ground services To regular transportation. On October 25, 1977, the Minister of Civil Aviation of the USSR B.P. Bugaev and the Minister of Aviation Industry of the USSR V.A. Kazakov approved the main document: “Act on the results of operational tests of a supersonic aircraft with NK-144 engines” with a positive conclusion and conclusions.
Based on the presented tables of compliance of the Tu-144 with the requirements of the Temporary Airworthiness Standards for Civilian Tu-144 of the USSR, the full volume of submitted evidentiary documentation, including acts on state and operational tests, on October 29, 1977, Chairman of the State Aviation Register of the USSR I.K. Mulkijanov approved the conclusion and signed the first airworthiness certificate in the USSR, type No. 03-144, for a supersonic aircraft with NK-144A engines.
The road was open for passenger traffic.

The road was open for passenger traffic.
The supersonic aircraft could land and take off at 18 airports in the USSR, while Concorde, whose takeoff and landing speed was 15% higher, required a separate landing certificate for each airport.

The second production copy of a supersonic aircraft.

In June 1973, the 30th International Paris Air Show took place in France. The interest generated by the Soviet Tu-144 airliner, the world's first supersonic aircraft, was enormous. On June 2, thousands of visitors to the air show in the Paris suburb of Le Bourget watched the second production copy of a supersonic aircraft take to the runway. The roar of four engines, a powerful take-off - and now the car is in the air. The sharp nose of the airliner straightened and aimed at the sky. The supersonic Tu, led by Captain Kozlov, made its first demonstration flight over Paris: having gained the required altitude, the car went beyond the horizon, then returned and circled over the airfield. The flight proceeded normally, no technical problems were noted.
The next day, the Soviet crew decided to show everything that the new one was capable of.

Disaster during a demonstration.

The sunny morning of June 3 did not seem to foretell trouble. At first everything went according to plan - the audience raised their heads and applauded in unison. The supersonic aircraft, showing the “top class”, began to descend. At that moment, a French Mirage fighter appeared in the air (as it later turned out, it was filming an air show). A collision seemed inevitable. In order not to crash into the airfield and spectators, the crew commander decided to rise higher and pulled the steering wheel towards himself. However, the height had already been lost, creating large loads on the structure; As a result, the right wing cracked and fell off. A fire started there, and a few seconds later the flaming supersonic plane rushed to the ground. A terrible landing occurred on one of the streets of the Parisian suburb of Goussainville. The giant machine, destroying everything in its path, crashed to the ground and exploded. The entire crew - six people - and eight Frenchmen on the ground were killed. Goosenville also suffered - several buildings were destroyed. What led to the tragedy? According to most experts, the cause of the disaster was the attempt of the crew of a supersonic aircraft to avoid a collision with the Mirage. During landing, the Tu was caught in a wake from the French Mirage fighter.

The photograph contains the signature of the first cosmonaut who landed on the moon, Neil Armstrong, pilot cosmonaut Georgiy Timofeevich Beregovoy and all the dead crew members. Supersonic aircraft No. 77102 crashed during a demonstration flight at the Le Bourget air show. All 6 crew members (Honored test pilot Hero of the Soviet Union M.V. Kozlov, test pilot V.M. Molchanov, navigator G.N. Bazhenov, deputy chief designer, engineer Major General V.N. Benderov, leading engineer B.A. Pervukhin and flight engineer A.I. Dralin) died.

According to the employees of the A.N. Tupolev Design Bureau, the cause of the disaster was the connection of an undebugged analog block of the control system, which led to a destructive overload.
According to the pilots, emergency situations occurred on almost every flight. On May 23, 1978, the second supersonic plane crashed. An improved experimental version of the airliner, Tu-144D (No. 77111), after a fuel fire in the engine nacelle area of ​​the 3rd power plant due to the destruction of the fuel line, smoke in the cabin and the crew turning off two engines, made an emergency landing on a field near the village of Ilyinsky Pogost, not far from the city Yegoryevsk.
After landing, crew commander V.D. Popov, co-pilot E.V. Elyan and navigator V.V. Vyazigin left the plane through the cockpit window. Engineers V.M. Kulesh, V.A. Isaev, V.N. Stolpovsky, who were in the cabin, left the aircraft through the front entrance door. Flight engineers O. A. Nikolaev and V. L. Venediktov found themselves trapped in their workplace by structures that were deformed during landing and died. (The deflected nose cone touched the ground first, worked like a bulldozer blade, picking up soil, and rotated under its belly, entering the fuselage.) On June 1, 1978, Aeroflot stopped supersonic passenger flights forever.

Improving supersonic aircraft.

Work on improving the supersonic aircraft continued for several more years. Five production aircraft were produced; another five were under construction. A new modification has been developed - Tu-144D (long-range). However, the choice of a new engine (more economical), RD-36-51, required significant redevelopment of the aircraft, especially power plant. Serious design gaps in this area led to a delay in the release of the new airliner. Only in November 1974, the serial Tu-144D (tail number 77105) took off, and nine (!) years after its first flight, on November 1, 1977, the supersonic aircraft received a certificate of airworthiness. Passenger flights opened on the same day. During their short operation, the liners carried 3,194 passengers. On May 31, 1978, flights were stopped: a fire broke out on one of the production Tu-144Ds, and the airliner suffered a disaster, crashing during an emergency landing.
The disasters in Paris and Yegoryevsk led to the fact that interest in the project on the part of the state decreased. From 1977 to 1978, 600 problems were identified. As a result, already in the 80s, it was decided to remove the supersonic aircraft, explaining this with “a bad effect on people’s health when crossing the sound barrier.” Nevertheless, four out of five Tu-144Ds in production were still completed. Subsequently, they were based in Zhukovsky and took to the air as flying laboratories. A total of 16 supersonic aircraft were built (including long-range modifications), which made a total of 2,556 sorties. By the mid-90s, ten of them had survived: four in museums (Monino, Kazan, Kuibyshev, Ulyanovsk); one remained at the plant in Voronezh, where it was built; another one was in Zhukovsky along with four Tu-144Ds.

Subsequently, the Tu-144D was used only for freight transport between Moscow and Khabarovsk. In total, the supersonic aircraft made 102 flights under the Aeroflot flag, of which 55 were passenger flights (3,194 passengers were carried).
Later, supersonic aircraft made only test flights and a few flights to set world records.
The Tu-144LL was equipped with NK-32 engines due to the lack of serviceable NK-144 or RD-36-51, similar to those used on the Tu-160, various sensors and test monitoring and recording equipment.
A total of 16 Tu-144 airliners were built, which made a total of 2,556 sorties and flew 4,110 hours (among them, aircraft 77144 flew the most, 432 hours). The construction of four more airliners was never completed.

Exactly 15 years ago, the last three supersonic passenger aircraft Concorde of the British airline British Airways made a farewell flight. On that day, October 24, 2003, these planes, flying at low altitude over London, landed at Heathrow, ending the short history of supersonic passenger aviation. However, today aircraft designers around the world are again thinking about the possibility of fast flights - from Paris to New York in 3.5 hours, from Sydney to Los Angeles in 6 hours, from London to Tokyo in 5 hours. But before supersonic aircraft return to international passenger routes, developers will have to solve many problems, among which one of the most important is reducing the noise of fast aircraft.

A short history of fast flights

Passenger aviation began to take shape in the 1910s, when the first airplanes specifically designed to transport people by air appeared. The very first of them was the French Bleriot XXIV Limousine from Bleriot Aeronautique. It was used for pleasure air rides. Two years later, the S-21 Grand appeared in Russia, created on the basis of the Russian Knight heavy bomber by Igor Sikorsky. It was built at the Russian-Baltic Carriage Plant. Then aviation began to develop by leaps and bounds: first flights began between cities, then between countries, and then between continents. Airplanes made it possible to get to your destination faster than by train or ship.

In the 1950s, progress in the development of jet engines accelerated significantly, and supersonic flight became available to military aircraft, albeit briefly. Supersonic speed is usually called movement up to five times faster than the speed of sound, which varies depending on the propagation medium and its temperature. At normal atmospheric pressure at sea level, sound travels at a speed of 331 meters per second, or 1191 kilometers per hour. As you gain altitude, the density and temperature of the air decrease, and the speed of sound decreases. For example, at an altitude of 20 thousand meters it is already about 295 meters per second. But already at an altitude of about 25 thousand meters and as it rises to more than 50 thousand meters, the temperature of the atmosphere begins to gradually increase compared to the lower layers, and with it the local speed of sound increases.

The increase in temperature at these altitudes is explained, among other things, by the high concentration of ozone in the air, which forms the ozone shield and absorbs part of the solar energy. As a result, the speed of sound at an altitude of 30 thousand meters above the sea is about 318 meters per second, and at an altitude of 50 thousand - almost 330 meters per second. In aviation, Mach number is widely used to measure flight speed. In simple terms, it expresses the local speed of sound for a specific altitude, density and air temperature. Thus, the speed of a conventional flight, equal to two Mach numbers, at sea level will be 2383 kilometers per hour, and at an altitude of 10 thousand meters - 2157 kilometers per hour. For the first time, American pilot Chuck Yeager broke the sound barrier at a speed of Mach 1.04 (1066 kilometers per hour) at an altitude of 12.2 thousand meters in 1947. This was an important step towards the development of supersonic flights.

In the 1950s, aircraft designers in several countries around the world began working on designs for supersonic passenger aircraft. As a result, the French Concorde and the Soviet Tu-144 appeared in the 1970s. These were the first and so far the only passenger supersonic aircraft in the world. Both types of aircraft used conventional turbojet engines optimized for long-term operation in supersonic flight. Tu-144 were in service until 1977. The planes flew at a speed of 2.3 thousand kilometers per hour and could carry up to 140 passengers. However, tickets for their flights cost on average 2.5–3 times more than usual. Low demand for fast but expensive flights, as well as general difficulties in operating and maintaining the Tu-144, led to their removal from passenger flights. However, the aircraft were used for some time in test flights, including under a contract with NASA.

Concorde served much longer - until 2003. Flights on French airliners were also expensive and were not very popular, but France and Great Britain continued to operate them. The cost of one ticket for such a flight was, in terms of today's prices, about 20 thousand dollars. The French Concorde flew at a speed of just over two thousand kilometers per hour. The plane could cover the distance from Paris to New York in 3.5 hours. Depending on configuration, Concorde could carry from 92 to 120 people.

The Concorde story ended unexpectedly and quickly. In 2000, the Concorde plane crash occurred, in which 113 people died. A year later in passenger air transportation the crisis began caused by the terrorist attacks of September 11, 2001 (two planes with passengers hijacked by terrorists crashed into the towers of the World shopping center in New York, another, the third, fell into the Pentagon building in Arlington County, and the fourth fell in a field near Shanksville in Pennsylvania). Then the warranty period for Concorde aircraft, which was handled by Airbus company. All these factors together made the operation of supersonic passenger aircraft extremely unprofitable, and in the summer and autumn of 2003 airlines Air France and British Airways took turns decommissioning all Concordes.


After the closure of the Concorde program in 2003, there was still hope for the return of supersonic passenger aircraft to service. Designers hoped for new efficient engines, aerodynamic calculations and computer-aided design systems that could make supersonic flights economically affordable. But in 2006 and 2008 International organization civil aviation adopted new aircraft noise standards that prohibited, among other things, any supersonic flights over populated land areas in Peaceful time. This ban does not apply to air corridors specifically designated for military aviation. Work on projects for new supersonic aircraft has slowed down, but today they have begun to gain momentum again.

Quiet supersonic

Today, several enterprises and government organizations in the world are developing supersonic passenger aircraft. Such projects, in particular, lead Russian companies Sukhoi and Tupolev, the Zhukovsky Central Aerohydrodynamic Institute, the French Dassault, the Japanese Aerospace Exploration Agency, the European concern Airbus, the American Lockheed Martin and Boeing, as well as several startups, including Aerion and Boom Technologies. In general, designers were divided into two camps. Representatives of the first of them believe that it will not be possible to develop a “quiet” supersonic aircraft that matches the noise level of subsonic airliners in the near future, which means that it is necessary to build a fast passenger aircraft that will switch to supersonic where it is allowed. This approach, the designers from the first camp believe, will still reduce the flight time from one point to another.

Designers from the second camp primarily focused on combating shock waves. When flying at supersonic speed, an aircraft's airframe generates many shock waves, the most significant of which occur in the nose and tail area. In addition, shock waves typically occur at the leading and trailing edges of the wing, at the leading edges of the tail, at the swirler areas and at the edges of the air intakes. A shock wave is a region in which the pressure, density and temperature of a medium experience a sudden and strong jump. By observers on the ground, such waves are perceived as a loud bang or even an explosion - it is because of this that supersonic flights over populated land are prohibited.

The effect of an explosion or a very loud bang is produced by so-called N-type shock waves, which are formed when a bomb explodes or on the glider of a supersonic fighter. On a graph of pressure and density growth, such waves resemble the letter N of the Latin alphabet due to a sharp increase in pressure at the wave front with a sharp drop in pressure after it and subsequent normalization. In laboratory experiments, researchers at the Japan Aerospace Exploration Agency found that changing the shape of the airframe can smooth out the peaks in the shock wave graph, turning it into an S-type wave. Such a wave has a smooth pressure drop that is not as significant as that of an N-wave. NASA experts believe that S-waves will be perceived by observers as a distant slam of a car door.


N-wave (red) before aerodynamic optimization of a supersonic glider and a similarity to the S-wave after optimization

In 2015, Japanese designers assembled the D-SEND 2 unmanned glider, whose aerodynamic shape was designed to reduce the number of shock waves generated on it and their intensity. In July 2015, the developers tested the airframe at the Esrange missile test site in Sweden and noted a significant reduction in the number of shock waves generated on the surface of the new airframe. During the test, D-SEND 2, not equipped with engines, was dropped from hot air balloon from a height of 30.5 thousand meters. During the fall, the 7.9-meter-long glider picked up a speed of Mach 1.39 and flew past tethered balloons equipped with microphones located at different heights. At the same time, the researchers measured not only the intensity and number of shock waves, but also analyzed the influence of the state of the atmosphere on their early occurrence.

According to the Japanese agency, the sonic boom from aircraft comparable in size to the supersonic passenger planes Concorde and designed according to the D-SEND 2 design, when flying at supersonic speeds, will be half as intense as before. The Japanese D-SEND 2 differs from the gliders of conventional modern aircraft in the non-axisymmetric arrangement of the nose. The keel of the vehicle is shifted towards the bow, and the horizontal tail unit is all-moving and has a negative installation angle relative to the longitudinal axis of the airframe, that is, the tips of the empennage are located below the attachment point, and not above, as usual. The glider's wing has a normal sweep, but is stepped: it smoothly mates with the fuselage, and part of its leading edge is located at an acute angle to the fuselage, but closer to the trailing edge this angle increases sharply.

According to a similar scheme, a supersonic American startup Aerion is currently being created and is being developed by Lockheed Martin for NASA. The Russian (Supersonic Business Aircraft/Supersonic Passenger Aircraft) is also being designed with an emphasis on reducing the number and intensity of shock waves. Some of the fast passenger aircraft projects are planned to be completed in the first half of the 2020s, but aviation regulations will not yet be revised by then. This means that the new aircraft will initially perform supersonic flights only over water. The fact is that in order to lift the restrictions on supersonic flights over populated land, developers will have to conduct many tests and submit their results for consideration aviation authorities, including the US Federal Aviation Administration and the European Aviation Safety Agency.


S-512 / Spike Aerospace

New engines

Another serious obstacle to the creation of a serial passenger supersonic aircraft is the engines. Designers today have already found many ways to make turbojet engines more economical than they were ten to twenty years ago. This includes the use of gearboxes that remove the rigid coupling of the fan and turbine in the engine, and the use of ceramic composite materials that allow optimizing the temperature balance in the hot zone of the power plant, and even the introduction of an additional third air circuit in addition to the already existing two, internal and external. In the field of creating economical subsonic engines, designers have already achieved amazing results, and ongoing new developments promise significant savings. You can read more about promising research in our material.

But, despite all these developments, it is still difficult to call supersonic flight economical. For example, a promising supersonic passenger aircraft from the startup Boom Technologies will receive three turbofan engines of the JT8D family from Pratt & Whitney or the J79 from GE Aviation. In cruising flight, the specific fuel consumption of these engines is about 740 grams per kilogram-force per hour. In this case, the J79 engine can be equipped with an afterburner, which increases fuel consumption to two kilograms per kilogram-force per hour. This consumption is comparable to the fuel consumption of engines, for example, of the Su-27 fighter, whose tasks are significantly different from transporting passengers.

For comparison, the specific fuel consumption of the world's only serial turbofan engines D-27, installed on the Ukrainian An-70 transport aircraft, is only 140 grams per kilogram-force per hour. The American CFM56 engine, a “classic” of Boeing and Airbus airliners, has a specific fuel consumption of 545 grams per kilogram-force per hour. This means that without a major redesign of jet aircraft engines, supersonic flights will not become cheap enough to become widespread, and will only be in demand in business aviation - high fuel consumption leads to higher ticket prices. It will also not be possible to reduce the high cost of supersonic air transportation by volume - the aircraft being designed today are designed to carry from 8 to 45 passengers. Conventional planes can accommodate more than a hundred people.

However, in early October of this year, GE Aviation projected a new Affinity turbofan jet engine. These power plants are planned to be installed on Aerion's promising AS2 supersonic passenger aircraft. The new power plant structurally combines the features of jet engines with a low bypass ratio for combat aircraft and power plants with a high bypass ratio for passenger aircraft. At the same time, there are no new or breakthrough technologies in Affinity. GE Aviation classifies the new engine as a power plant with a medium bypass ratio.

The engine is based on a modified gas generator from the CFM56 turbofan engine, which in turn is structurally based on the gas generator from the F101, the power plant for the B-1B Lancer supersonic bomber. The power plant will receive an upgraded electronic digital engine control system with full responsibility. The developers did not disclose any details about the design of the promising engine. However, GE Aviation expects that the specific fuel consumption of the Affinity engines will not be much higher than or even comparable to the fuel consumption of modern turbofan engines of conventional subsonic passenger aircraft. How this can be achieved for supersonic flight is not clear.


Boom / Boom Technologies

Projects

Despite the many projects of supersonic passenger aircraft in the world (including even the unrealized project of converting the Tu-160 strategic bomber into a supersonic passenger airliner proposed by Russian President Vladimir Putin), the AS2 of the American startup Aerion, S-512, can be considered the closest to flight testing and small-scale production Spanish Spike Aerospace and Boom American Boom Technologies. The first is planned to fly at Mach 1.5, the second at Mach 1.6, and the third at Mach 2.2. The X-59 aircraft, created by Lockheed Martin for NASA, will be a technology demonstrator and a flying laboratory; there are no plans to launch it into production.

Boom Technologies has already announced that they will try to make flights on supersonic aircraft very cheap. For example, the cost of a flight on the route New York - London was estimated by Boom Technologies at five thousand dollars. This is how much it costs today to fly on this route in business class on a regular subsonic airliner. The Boom airliner will fly at subsonic speed over populated land and switch to supersonic speed over the ocean. The aircraft, with a length of 52 meters and a wingspan of 18 meters, will be able to carry up to 45 passengers. By the end of 2018, Boom Technologies plans to select one of several new aircraft projects for implementation in metal. The first flight of the airliner is planned for 2025. The company postponed these deadlines; Boom was originally scheduled to fly in 2023.

According to preliminary calculations, the length of the AS2 aircraft, designed for 8-12 passengers, will be 51.8 meters, and the wingspan will be 18.6 meters. The maximum take-off weight of the supersonic aircraft will be 54.8 tons. AS2 will fly over water at a cruising speed of Mach 1.4-1.6, slowing to Mach 1.2 over land. The somewhat lower flight speed over land, coupled with the special aerodynamic shape of the airframe, will, as the developers expect, almost completely avoid the formation of shock waves. The aircraft's flight range at a speed of Mach 1.4 will be 7.8 thousand kilometers and 10 thousand kilometers at a speed of Mach 0.95. The first flight of the aircraft is planned for the summer of 2023, and the first transatlantic flight will take place in October of the same year. Its developers will mark the 20th anniversary of the last flight of Concorde.

Finally, Spike Aerospace plans to begin flight testing a full prototype of the S-512 no later than 2021. Deliveries of the first production aircraft to customers are scheduled for 2023. According to the project, the S-512 will be able to carry up to 22 passengers at speeds up to Mach 1.6. The flight range of this aircraft will be 11.5 thousand kilometers. Since October last year, Spike Aerospace has launched several scaled-down models of supersonic aircraft. Their purpose is to test the design solutions and effectiveness of flight control elements. All three promising passenger aircraft are being created with an emphasis on a special aerodynamic shape that will reduce the intensity of shock waves generated during supersonic flight.

In 2017, the volume of air passenger traffic worldwide amounted to four billion people, of which 650 million made long-haul flights ranging from 3.7 to 13 thousand kilometers. 72 million long-haul passengers flew first and business class. It is these 72 million people that developers of supersonic passenger planes are targeting first, believing that they will gladly pay a little more money for the opportunity to spend about half as much time in the air as usual. However, supersonic passenger aviation, most likely, will begin to actively develop after 2025. The fact is that research flights of the X-59 laboratory will begin only in 2021 and will last several years.

Research results obtained during X-59 flights, including over settlements- volunteers (their residents agreed to have supersonic planes fly over them on weekdays; after the flights, observers will tell researchers about their perception of noise), it is planned to submit it to the US Federal Aviation Administration. It is expected that on their basis it may revise the ban on supersonic flights over populated land, but this will not happen before 2025.


Vasily Sychev

One example of existing supersonic aircraft projects.

Today I’ll start with a short introduction :).

On this site I already have flights of aircraft. That is, it’s high time to write something about supersonic, especially since I promised to do it :-). The other day I set to work with considerable zeal, but realized that the topic is as interesting as it is voluminous.

My articles lately have not been particularly short, I don’t know if this is an advantage or a disadvantage :-). And the issue on the topic “ supersonic“threatened to become even larger and it’s not known how long it would take me to “create” it :-).

So I decided to try to make a few articles. A sort of small series (three or four pieces), in which each component will be devoted to one or two concepts on the topic supersonic speeds. And it will be easier for me, and I will bother my readers less :-), and Yandex and Google will be more supportive (which is important, you understand :-)). Well, what comes out of this is up to you to judge, of course..

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So, let's talk today about supersonic and supersonic aircraft. The very concept of " supersonic“in our language (especially in the superlative degree) flashes much more often than the term “subsonic”.

On the one hand, this is, in general, understandable. Subsonic aircraft have long become something completely commonplace in our lives. A supersonic aircraft, even though they fly to airspace for 65 years now, but they still seem to be something special, interesting and worthy of increased attention.

On the other hand, this is quite fair. After all, flights to supersonic- this, one might say, is a separate area of ​​movement closed by some kind of barrier. However, inexperienced people may well have a question: “What, exactly, is so outstanding about this supersonic sound? What difference does it make if a plane flies at a speed of 400 km/h or 1400 km/h? Give him a more powerful engine and everything will be fine!” Aviation was in approximately this semantic position at the dawn of its development.

Speed ​​has always been the ultimate dream, and initially these aspirations were quite successfully translated into reality. Already in 1945, Messerschmitt test pilot L. Hoffmann, in horizontal flight on one of the world's first aircraft with jet engines, ME-262, reached a speed of 980 km/h in horizontal flight at an altitude of 7200 m.

However, in reality everything is far from so simple. After all, the flight to supersonic differs from subsonic not only in the magnitude of the speed and not so much by it. The difference here is qualitative.

Already at speeds of about 400 km/h, such a property of air as compressibility begins to gradually manifest itself. And, in principle, there is nothing unexpected here. - it's gas. And all gases, as is known, unlike liquids, are compressible. When compressed, gas parameters change, such as density, pressure, temperature. Because of this, various physical processes can proceed differently in a compressed gas than in a rarefied gas.

The faster the plane flies, the more it, together with its aerodynamic surfaces, becomes like a kind of piston, in a certain sense compressing the air in front of it. It’s exaggerated, of course, but in general that’s how it is :-).

As the speed increases, the aerodynamic pattern of flow around the aircraft changes, and the faster, the more :-). And on supersonic she is already qualitatively different. At the same time, new concepts of aerodynamics come to the fore, which often simply do not make any sense for low-speed aircraft.

To characterize flight speed, it now becomes convenient and necessary to use such a parameter as the Mach number (Mach number, the ratio of the speed of the aircraft relative to the air at a given point to the speed of sound in the air flow at that point). Another type of aerodynamic resistance appears and becomes noticeable (very noticeable!) - characteristic impedance(along with the already increased normal drag).

Such phenomena as wave crisis (with a critical number M), supersonic barrier, shock waves and shock waves.

In addition, the controllability and stability characteristics of the aircraft deteriorate due to the rearward displacement of the point of application of aerodynamic forces.

When approaching the region of transonic speeds, the aircraft may experience severe shaking (this was more typical for the first aircraft that stormed the then mysterious boundary of the speed of sound), similar in its manifestations to another very unpleasant phenomenon that aviators had to face in their professional development. This phenomenon is called flutter (topic for another article :-)).

Such an unpleasant moment appears as the heating of the air as a result of its sharp braking in front of the aircraft (the so-called kinetic heating), as well as heating as a result of viscous friction of air. At the same time, the temperatures are quite high, about 300ºС. The skin of an aircraft heats up to these temperatures during a long supersonic flight.

We will definitely talk about all the concepts and phenomena mentioned above, as well as the reasons for their occurrence, in other articles in more detail. But now, I think it’s quite clear that supersonic- this is something completely different than flying at subsonic (especially low) speed.

In order to get along with all the newly emerging effects and phenomena at high speeds and fully correspond to its purpose, the aircraft must also change qualitatively. Now this must be supersonic aircraft, that is, an aircraft capable of flying at speeds exceeding the speed of sound in a given area of ​​airspace.

And for it, just increasing engine power is not enough (although this is also a very important and mandatory detail). Such aircraft usually change in appearance. Sharp corners and edges and straight lines appear in their appearance, in contrast to the “smooth” outlines of subsonic aircraft.

Supersonic aircraft They have a swept or triangular wing in plan. A typical and one of the most famous delta-wing aircraft is the wonderful MIG-21 fighter ( maximum speed at an altitude of 2230 km/h, at the ground 1300 km/h).

Supersonic aircraft with a delta wing MIG-21.

One of the swept wing options is an ogival wing, which has an increased lift coefficient. It has a special influx near the fuselage, designed to form artificial spiral vortices.

MIG-21I with an ogival wing.

MIG-21I - ogival wing.

Ogival wing of TU-144.

It is interesting that a wing of this type, later installed on the TU-144, was tested on a flying laboratory based on the same MIG-21 (MIG-21I).

Second option - supercritical wing. It has a flattened profile with a specially curved rear part, which makes it possible to delay the occurrence of a wave crisis at high speeds and can be advantageous in terms of efficiency for high-speed subsonic aircraft. This wing was used, in particular, on the SuperJet 100 aircraft.

SuperJet 100. An example of a supercritical wing. The profile bend is clearly visible (rear part)

Photos are clickable.