Tu-95 History

Work on the creation of a high-speed strategic bomber with an intercontinental flight range (that is, capable of taking off from Soviet airfields to reach the territory of the United States and return) of a nuclear weapons carrier aircraft, which received the factory code "95" (aircraft "B") began at OKB A . N. Tupolev in the spring of 1950. The aircraft was supposed to be equipped with a wing-based refueling system in the air (the flight range with one refueling was supposed to be increased to 18,400 km, and the maximum range with several refuelings - 32,000 km.)

The creation of the Tu-95 high-speed long-range bomber was facilitated by: first, the introduction of new requirements for a manned strategic nuclear weapon by the Air Force; secondly, new directions in the development of the configuration of a transonic heavy aircraft and the choice of its main parameters; third, the emergence of new powerful and economical power plants based on turboprop engines. In 1949, a nuclear bomb was created and tested in the USSR, which put an end to the "atomic monopoly" of the United States. Nevertheless, there was no need to talk about the parity of the military capabilities of the two main enemies in the Cold War, since the Soviet Union did not yet have the necessary "delivery vehicles" - neither aviation nor missile. The farthest bomber remained the Tu-4, a copy of the famous American B-29 aircraft. Using specially prepared sites in the Arctic Ocean, the Tu-4 could theoretically reach the United States, however, this method was clearly ineffective.

Design Bureau A.N. Tupolev (OKB-156), starting in 1948, on its own initiative began to develop a model of the aircraft, which received the preliminary designation "85". It was a four-engine all-metal bomber with a straight wing and piston engines, capable of flying up to 12,000 kilometers with a bomb load. The first such machine was demonstrated at the air parade in Tushino on May 12, 1951. Preparations were made for serial production, however, it never began.

The reason for abandoning the aircraft "85" was the results of air battles in Korea. During this conflict, Soviet MiG-15 jet fighters repeatedly smashed large B-29 formations, thereby proving that the age of military piston aviation was over. Until recently, almighty, she has exhausted all the possibilities to improve key performance characteristics. At the same time, it was clear that aircraft "85" would be in enemy airspace no less vulnerable than American bombers in the skies of Korea. Thus, the Soviet strategic aviation needed faster machines equipped with jet engines rather than piston engines.

The first to create such an aircraft, capable of flying long distances at high speed, was the aircraft designer V.M. Myasishchev, who proposed the project of the SDB bomber, later known as the M4. In 1950 V.M. Myasishchev turned to the government with a proposal to create a strategic bomber with a maximum speed of 950 km / h and a range of more than 13,000 km. It was proposed to build the aircraft with 4 AM-3 turbojet engines developed by the A.A. Mikulin Design Bureau. The proposal was accepted.

On March 24, 1951, the USSR Council of Ministers issued a decree on the restoration of the V.M. Myasishchev Design Bureau. This new design bureau, designated OKB-23, was instructed to create a high-speed intercontinental strategic bomber as soon as possible, capable of reaching the United States with a nuclear bomb weighing 5 tons, breaking through its air defense, delivering a nuclear strike and returning to its base in the USSR. The best forces of the Soviet aviation industry are involved in work on the aircraft, which later received the designation M-4, and practically unlimited funding for the work opens.

A.N. Tupolev was well informed about the unfolding work on the M-4 and was ready to join the competition with his former student and colleague for the right to create a high-speed strategic bomber. Tupolev, at first, considered such undertakings unrealistic, since the first turbojet engines were too "gluttonous". There were other serious problems, for example, at subsonic speeds, flutter (destructive oscillations) of long swept wings occurred.

Talking with Stalin, Tupolev mentioned these important details, but the aircraft designer could not convince the head of the USSR. The backwardness of piston aircraft became too obvious, it was already impossible to ignore it. As a result, OKB-156 received an official order from the government, which provided for the creation of a high-speed bomber with four turboprop engines for the Air Force.

Work on the Tu-16 and Tu-85, the experience of world aircraft construction made it possible by 1951 to form the appearance of the future Tupolev high-speed ultra-long-range bomber. In the Design Bureau, an airplane with a takeoff weight of about 150 tons, with a sweep wing of 35¦ and an aspect ratio of 9 was drawn. Such a wing by that time had been sufficiently well studied at TsAGI and should not have caused any particular problems either for aerodynamics, or for structural engineers, or for designers and technologists. The fuselage of the new aircraft was basically supposed to repeat the fuselage of the "85" aircraft. But the type of engines remained a big question. Turbojet or turboprop - this is the main dilemma that faced the designers of the future machine. Large-scale research, carried out in 1950 and at the beginning of 1951 at OKB-156, together with related organizations, showed that to obtain an aircraft with the necessary combinations of speed and range parameters, the most acceptable way for that period was the installation of 4 turboprop engines with a capacity of 10,000-12,000 e. .from. each, with specific fuel consumption of the order of 0.25-0.3 kg / hp h.

the team of B.M. Kondorsky worked on various options for power plants with turbojet and turboprop engines, as well as their combinations. The search began with an attempt to use ready-made designs of OKB aircraft (Tu-85 and Tu-4) for new tasks. The options for installing turboprop engines TV-2 instead of the ASh-73TK on the Tu-4 were reviewed, in this version the maximum speed of the Tu-4 aircraft was increased to 676 km / h, and the flight range was up to 6900 km. This project, designated aircraft "94", became the basis for attempts to propose modernization of the fleet of serial Tu-4s. The second direction was the projects of modernization of the project "85" for the TV-2F or TV-10 engines. In this case, the estimated flight range was 16000-17200 km, and the maximum speed was 700-740 km / h. The results obtained did not suit anyone; it was not possible to pour new wine into familiar old bottles. It was necessary to move on.

Two similar aircraft were chosen for comparison, one with 4 turbojet engines, the other with 4 turbo-props. The comparison showed that it was possible for TV-2 to obtain a flight range of over 13,000 km with the variant with the use of 4 turbo-props with a takeoff power of 12000-15000 ehp. At the same time, the take-off weight of such an aircraft reached 200 tons, and the estimated maximum speed at an altitude of 10,000 m would be about 800 km / h. The takeoff run of such an aircraft would be 1500 m. A similar aircraft with 4 turbojet engines of 9000 kg each of take-off thrust (AM-3 engines) would have, at best, a maximum flight range of no more than 10,000 km and a takeoff run of more than 2000 m.Its only advantage was a maximum speed of -900 km/h.

Comrade Stalin, having entrusted this work to the newly formed OKB-23, nevertheless decided to play it safe and at the same time give a similar task to Tupolev. Here is how one of his deputies L.L. Kerber recalled this meeting, who received information about this conversation directly from Andrei Nikolaevich:

"... Comrade Tupolev," said Stalin, "is it possible to install additional engines on one of your bombers so that it can reach the United States, complete the task, and then, upon returning, report the results?"

I replied that this is not the point, but that domestic engines are not economical and require a huge amount of fuel for such a flight, which cannot be accommodated in existing aircraft.

- So, in your opinion, it is not possible?

- Yes, Comrade Stalin, that's right.

Stalin was silent for a while, then went to the table, opened the folder that was on it, turned over several pages and said:

- It's strange. But our other designer reports that it is possible, and undertakes to solve the problem.

He closed the folder and let go of me with a nod of his head. I realized that he was extremely displeased. "

The result of this conversation was the direction OKB-156 of work on a new strategic aircraft, which received the code of the OKB aircraft "95". The previous developments on the 85 aircraft greatly helped Tupolev both in the creation of a new aircraft and in the subsequent establishment of its serial production. By this time, the actually existing TV-2 type turbo-prop engine developed by OKB-276 in Kuibyshev, led by N.D. Kuznetsov, had a take-off power of about 5000 ehp. This engine was developed on the basis of the captured German engine JuMO-022 by interned German specialists. The prototype of the engine, which had the initial designation TV-022, passed State bench tests in October 1950. Its boosted version TV-2F had a power of 6250 ehp. At the same time, OKB-276 had begun work on TV-10 and TV-12 engines for takeoff power of 10,000 and 12,000 hp. respectively. These most powerful turbo-propsin the world could be ready only in 1.5-2 years, but the engine for the 95 aircraft was needed now. A.N. Tupolev personally flew to Kuibyshev to meet with Kuznetsov in order to understand the prospects of the new power plant. As a result of the trip and familiarization with the problem on the spot, A.N.Tupolev decided to lay the project in two versions for two power plants: the first - for a pair of real-life TV-2F, the second - for prospective double-power engines in one unit. OKB276 urgently designed and built a pair of two TV-2Fs working on a common gearbox. The new engine received the designation 2TV-2F, its take-off power reached 12,000 ehp, just what was needed for the new aircraft.

On July 11, 1951, the Resolution of the Council of Ministers of the USSR No. 2396-1137, followed by MAP Order No. 654, according to which the design bureau of A.N. Tupolev was instructed to design and build a high-speed long-range bomber in two versions: the 1st with four twin TVDs of the 2TV-2F type with its transfer for flight tests in September 1952; The second - with four TV-12s with a date of transfer for flight tests in September 1953. Four days later, on November 15, 1951, the issue of the forthcoming serial production of the aircraft was decided.

In November 1952, a prototype bomber, designated "95-1", took to the air for the first time. Over the next six months, 16 successful test flights were performed, and on May 11, 1953, there was a disaster. The cause of the tragedy was not weather conditions, but a defect in the engine design, which caused the destruction of gears and a fire. The plane, carrying several tens of tons of kerosene on board, crashed into the swampy underbrush, exploded and formed a crater up to 10 meters deep. The results of the catastrophe - four dead, seven escaped by parachutes and the destroyed hope of Soviet strategists.

The first reaction of the Air Force Command to the disaster explaining the catastrophe was developed and supported in the engine department under the Commander-in-Chief and by the engine specialists themselves from OKB-276. Everything in this version was explained simply: the engine mount of the third engine collapsed, the engine came off, fuel gushed out, and a fire started. Everything is very clear. The premise of the disaster is the negligence of the military representative of plant No. 156. A Submission from the Commander-in-Chief to hand over to the Military Tribunal the senior military representative of the Air Force at Plant No. 156 Guard engineer-lieutenant colonel S.D. Agavelyana, as the main culprit of the disaster. Dvigatelists insisted that the gear had broken from the impact and that the cause of the disaster was the destruction of the motor mount. Clouds were gathering over A.N. Tupolev.

Stalin had died in March 1953, but practically nothing had changed in the country, the terrible repressive machine continued to work. Sympathy itself or liberalism towards the guilty was considered a crime. A.N.Tupolev had already tasted the prison gruel. Dvigatelists and many members of the commission together smashed A. N. Tupolev, accusing him of all mortal sins. Some, in the style of the time, agreed that it was impossible to trust the design of the Soviet strategic aircraft to a former "enemy of the people."

Earlier technical test results revealed that at the 30th and 40th hours of operation of the 2TV-2F engines on bench tests there was a destruction of the gears of the reducers with a fire in the test boxes. ND Kuznetsov, who was sitting with his head bowed, was reviled for about an hour. Finally, A.N. Tupolev took the floor. Everyone was impatiently waiting for him to "grind" Kuznetsov into powder, but Tupolev began to talk about something completely different.

Having scolded Kuznetsov for hiding facts, he got to the heart of the matter, saying: "Who doesn't make mistakes? Who was not mistaken? The Chief Designer of 2TV-2F must be reprimanded for hiding a fact, but these are details. Offering the most severe measures in relation to him, right up to the shooting, you talked about the benefits of the case, but it can only do great harm to the country's defense capability. This ill-fated engine is on the Tu-95, with which we are trying to create a balance with the United States. While we were in this office for almost two weeks engaged in a discussion, Khrunichev and I were summoned to the Government more than once and tried to find out what ways there were to get the Tu-95 on its feet. What some comrades are proposing will completely ruin this order of state importance. To decapitate OKB-276, remove the head - this means ditching the world's most powerful engine, and at the same time the Tu-95. This cannot be done. Our decisions should be aimed at supporting further work on the 2TV-2F engines and its variants. And in order to achieve this goal, it is necessary to help Kuznetsov, and not to put him in prison. That's what I wanted to say!"

The MAP order No. 114 dated October 15, 1953. The order named the reasons for the disaster: the destruction of the intermediate gear of the gearbox of the 2TV-2F engine due to its insufficient fatigue strength and the inadequacy of the onboard fire extinguishing equipment of the 95 aircraft. Chief designers Tupolev, Myasishchev, Kuznetsov, Mikulin were charged with ensuring high-quality and accident-free flight tests of Tu-95 and M-4 aircraft. Tupolev, Kuznetsov and Makarevsky (head of TsAGI), prior to the start of flight tests of the 95-2 aircraft with TV-12 engines, had to organize and conduct static tests of the TV-12 with the nacelle of the aircraft, as well as additional static and vibration tests on the Tu-95.

The crash of the 95-1 prototype significantly delayed the process of creating the aircraft. This was largely due to the complexity of "fine-tuning" the NK-12 engine. Production of the "understudy" airframe was completed in November 1952. Until July 1954, there was an endless chain of improvements and changes on an almost finished machine. And for almost half a year the aircraft "95-2" was in the assembly shop of the pilot plant. There were no engines. Only in February 1955, the cycle of flight and technical tests continued. Even before its completion, serial production of bombers began, this time under the official name Tu-95.