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Tu-104

 

 

In June, 2005 Tu-104, the first Soviet jet passenger aircraft, marked half-century anniversary of the beginning of its flight tests. Creation of Tu-104 and its assimilation in wide operation became an important milestone in the history of world aviation.
The successful introduction of airplanes with turbojet engines in the Air Force allowed switching to the problem of creating a jet passenger aircraft for civil aviation. The prototype of the world's first production jet passenger airplane, named "Comet", was produced in the UK in 1949. After several years of testing and development, the airplane started operations in the civil air fleet. However, a series of crashes in the first half of the 50s forced airlines to remove the aircraft from service. It took four years of additional research and design improvements before almost new "Comet" was back in service.

 

 

In the end of 1953, the Design Bureau’s leaders, headed by A.N. Tupolev, basing on the positive experience of developing, testing and beginning of serial production of Tu-16, proposed the idea of creating jet passenger aircraft on its basis to the leadership of the country. Soon, Tupolev made a report to the Central Committee of the Communist Party on the proposal. The report focused the attention of the country's leadership on the benefits of the modification approach to the design of the first domestic passenger plane. The following features concerning aircraft operation were noted: a high cruising speed (three times more than that of Li-2 and IL-12 – Aeroflot’s main passenger airplanes of the period); the capability of flying at high altitudes without turbulence; high carrying capacity and passenger capacity, while providing high comfort. For the first time in the USSR, the issue was a creation of a large-production civil aircraft of "liner" class for the CAF that could make high-speed air transport a mass means of transportation.

 

Andrey N. Tupolev and his colleagues managed to prove to the leadership of the country, industry and the CAF, the capability of providing affordable economic performance of jet liners, even taking into account the sharp increase of fuel costs after implementation of these airplanes. According to the assessments performed in the Bureau, in conditions of the USSR, in case of the introduction of jet airliners, for improving the efficiency of the transport system it was necessary to extend the life time of these airplanes up to 25,000-30,000 flight hours, instead of 10,000 hours for piston-engined aircraft; increase payload, by building airplanes for 50-100 or more passengers; increase cruise speed up to 750-800 km/h. According to the opinion of the Bureau’s leadership, creation of passenger jet by modifying Tu-16 long-range jet bomber, mastered in production and operation, would give significant economic benefits. In this case, the experience of building, finishing and maintenance of military prototype was used completely, that provided high reliability and operational safety, so important for passenger aircraft. The cost of implementation of the aircraft into batch production was significantly reduced too, thereby reducing the cost of the aircraft and increasing its economic characteristics. The problem of training pilots and ground crews for the new passenger aircraft was facilitated through the use of specialists trained in the Air Force on the airplanes with design, flight and operational characteristics close to those of the passenger jets. This concept, in relation to passenger jet, was a continuation and development of the ideas accepted by the Bureau during the 20s - 40s, that had been formed during the design and construction of a series of piston-engined passenger and cargo aircraft. The most remarkable was wide structural unification of ANT-9 (PS-9) and ANT-14 "Pravda" passenger airplanes with ANT-4 (TB-1), ANT-6 (TB-3) bombers and ANT-7 (R-6) multi-purpose aircraft, as well as designing ANT-20 "Maxim Gorkiy" and ANT-28 passenger "giants" on the basis of the layout and design solutions of a series of super heavy bombers ANT-16 (TB-4) and ANT-26 (TB-6). In the second half of the 40s, during the successful implementation of Tu-4 into batch production, the Bureau of A.N. Tupolev has prepared a profound modification of this long-range bomber - Tu-70 passenger liner and Tu-75 cargo airplane, which successfully passed the cycle of tests and developments, but were not accepted for mass production and operation due to lack of necessary facilities for their production, and what was more important, due to the fact that the USSR’s market of aviation services and operators were not ready for switching to the modern airplanes.

Even before the official decision on the aircraft, the Bureau had started works on its development. On June 11, 1954 the Council of Ministers of the USSR issued a decree № 1172-516 on creation a long-range high-speed passenger aircraft designated Tu-16P (within the Bureau it had "104" designation, which further became its official - Tu-104, then the last number "4" became a constant figure in the official designation of Tupolev passenger airplanes). It was to be designed on the basis of Tu-16 airplane with two AM-3-200 engines. Serial production was imposed on the plant № 135 in Kharkov.
The transition from Tu-16 to Tu-104 was carried out by replacing the fuselage with the newly designed one of increased diameter (3.5 m instead of 2.9 m) with pressurized cabin from the nose to the empennage compartment. The scheme of the aircraft was also changed: the aircraft became low-wing instead of mid-wing monoplane, that’s why center wing and nacelles were modified. The following assemblies of Tu-16 were used: outer wing, engine compartments of the wing, landing gear, horizontal tail, vertical tail and landing gear fairings. Initially, Tu-104 was designed for 50 passengers, although a further transition for 70 or more passengers in case of success of the project was provided from the beginning.
In September, 1954 the preliminary design of Tu-104 was presented to the Air Force. In November and December, a mock-up committee was performed, while detailed design and construction of prototype aircraft were under way.
During the creation of Tu-104, special attention was paid to ensuring high reliability of the aircraft structure, as well as increasing life time of the airframe and especially of pressurized cabin. Bearing in mind the challenges faced by the British with "Comet", airframe of Tu-104 for the first time in the Soviet practice was cycled in TsAGI’s new purpose-built water-tank, within the framework of Tu-104 creation program. These tests had revealed weaknesses in the design, thus, the redesign was performed to ensure its durability was enough.
At the same time, a search for the most rational layouts of passenger cabins, galley and domestic compartments was being performed for the aircraft. Comfortable passenger seats and shadow-free lighting were being developed; interior’s color palette and materials for upholstery of chairs and partitions were being chosen. The interior of the aircraft was being designed with the idea that a sense of comfort and security can be achieved by creating a "home environment" in the airplane ("House-cabin" idea). Hence, the interior was a little bit overfilled with elements of traditional imperial style and both the total space and individual parts didn’t resemble a unity; shapes and design of wagon architecture were used as well as gold and walnut finish. All these interior features existed only on the first prototype. Later, in batch production, the interior of the passenger compartment became more "democratic", approaching the international standards of the period.

Passenger aircraft specificity has necessitated the development of new units of air conditioning systems, electrical units for food cooking and warming up, new lighting, radio installation of passenger cabins, etc. All that was, to a large extent, just being mastered by our aviation industry, that had been working for many years mainly for the mass military contracts. In addition to it, increased requirements on reliability were imposed on the previously developed systems and units. Some new units, mainly for domestic service, have been designed in the Tupolev Design Bureau, because the specialized bureaus refused to deal with the subject, having no experience of designing specific units of passenger aircraft.
By the beginning of 1955, Tu-104 prototype with AM-3 engines was finished in prototype production and immediately transferred to the Bureau’s Flight Test and Development base in Zhukovskiy, where its development and preparation for tests began. Factory tests of the prototype started on June 11, 1955 and continued till October 12, 1955. Tests were carried out by the crew consisting of the following persons: captain – test-pilot Y.T. Alasheev, copilot - B.M. Timoshok, navigator - P.N. Rudnev, chief engineer - V.N. Benderov. B.F. Petrov was appointed the chief engineer from the Bureau for Tu-104, while the general management of the project, as with Tu-16, was carried out by D.S. Markov, who later became the chief designer of the aircraft.
Tu-104 prototype performed its first flight on June 17, 1955.
The data obtained during the factory tests met almost all the requirements for the airplane, given in the decree of the Council of Ministers, except for the take-off run, which was corrected by installation of more powerful AM-3M engines. The plane was then recommended for transfer to the state tests.
While the factory tests were under way, production plant № 135 was being prepared for batch production of Tu-104. Hard work on putting the aircraft into production was as tough as it would be in the years of the Great Patriotic War. Less than a year after issuing the decree of the Council of Ministers, the first production Tu-104 was being finished in the newly built assembly shop of the plant (it should be noted that the roof of the shop was not finished yet at that point). On November 5, 1955 the first serial aircraft Tu-104 performed its first flight piloted by the crew of test-pilot V.F.Kovalev, followed by two more airplanes of zero batches, which by May, 1956 were ready for field tests. In August, 1956 the first preproduction aircraft was ready – it was flown for the first time and factory tested by the plant’s test-pilot F.F. Dotsenko. Then, full-scale production of Tu-104 began.

The state tests of the first prototype took place in the Air Force State Scientific Research Institute of the Red Banner from January 31, 1956 to June 15, 1956. The state tests were performed by the crew headed by A.K. Starikov, who had successfully tested Tu-16 before and has done a lot to teach its younger passenger "brother" to fly. During tests, a large number of flights related to the following emergencies were performed: failure of one of the engines during take-off, fuel dumping in flight, aborted take-off, emergency descent from high altitudes, determination of stall characteristics, check of the effectiveness of anti-icing systems, etc. During the state tests on March 22, 1956 Tu-104 prototype flew to London with a group of diplomats and I.A. Serov, the chairman of the KGB, who was preparing visit of N.S. Khrushchev and N.A. Bulganin to England. The emerging of Tu-104 in Western Europe caused a real furor in the aviation and general public at the other side of the "iron curtain". It became clear for the Europe that the Soviet Union had brilliantly mastered the complex technologies of aircraft industry and was capable of producing not only modern combat jet airplanes (which the West met during Korean War not so long ago), but also first-class passenger jets.
Field tests of the first two production aircraft began almost simultaneously with the state tests of the prototype. The former were carried out by the CAF with the help of the Ministry of Aircraft Production, specifically, chief engineers of the Bureau B.N. Grozdov V.N. Benderov took part in them.

 

A squadron of jets specially organized in Moscow’s Vnukovo airport became the pioneer of mastering Tu-104 in the CAF. It was also the first educational and training squadron, which retrained crews of other airlines for new jets. The pilots of the highest class, such as K.P. Sapelkin, E.P. Barabash, B.P. Bugaev, A.V. Orlovets and others were among the pioneers of jet passenger aviation. They were the first who have mastered Tu-104 and then, they took part in its field tests. On September 15, 1956 Tu-104 performed its first scheduled flight with passengers en Moscow-Irkutsk air route, the plane was piloted by a crew headed by E.P. Barabash. On October 12 Tu-104 performed its first regular international flight to Prague piloted by a crew headed by B.P. Bugaev (who later became chief pilot for L.I. Brezhnev, and then the head of the Soviet CAF). The regular operation of the aircraft began, opening a new era in the development of Soviet civil aviation, and also pushing the development of the global jet passenger aviation. Tu-104 is the world's first passenger jet, successfully mastered by the CAF which was followed by such airplanes as Boeing 707, "Comet-4," and the French "Caravel" entering service. Thus, jet passenger aviation became a reality available to a wide range of passengers in many countries.
Following the batch production at the plant № 135, production was started at the plant № 166 in Omsk. In 1957, both plants switched to Tu-104A modification for 70 passengers. In 1958, the batch production of Tu-104 was started at the plant № 22 in Kazan, which has mastered Tu-104B modification for 100 passengers. Just before termination of batch production in 1960, three plants had built 201 aircraft. 6 Tu-104A airplanes were delivered to Czechoslovakia. In 1957, General Designer (since December, 1956) A.N. Tupolev, and a number of his deputies and leading experts of the Bureau (A.A. Arkhangelskiy, N.I. Bazenkov, D.S. Markov, S.M. Eger, A.R. Bonin, A.E. Sterlin, L.L. Kerber, K.V. Minkner, A.M. Cheriomukhin) were awarded the Lenin Prize for the creation of Tu-104. More than 400 employees of the Bureau and the aircraft development plant have been awarded various governmental awards.
During the batch production, Tu-104 was repeatedly modified and modernized: AM-3 engines were replaced with more powerful and reliable RD-3, RD-3M and RD-3M-500 engines; modifications with an increased passenger capacity were prepared for production; the equipment, mainly flight and navigation as well as radio and communication, was constantly updated. All this made it possible to maintain the fleet of Tu-104 at the modern level throughout the life cycle of the aircraft.


Modifications and variants of the aircraft:
- Tu-104 - the first production aircraft for 50 passengers. 29 airplanes have been built;
- Tu-104A - modification of the aircraft for 70 passengers. 80 airplanes have been built, six of which were delivered to Czechoslovakia, where they were in operation for several years;
- Tu-104B - modification of the aircraft for 100 passengers, with a longer fuselage and extended lift devices. 95 airplanes have been built. During operation, Tu-104B were converted to Tu-104B-115 for 115 passengers and were fitted with a new flight and navigation and radio equipment;
- Tu-104V - unfulfilled project of production aircraft for 117 passengers;
- Tu-104G and Tu-104D - versions of the aircraft with higher level of comfort for special air transportations;
- Tu-104E - prototype aircraft with more fuel-efficient RD-16-15 engines (thrust of 11,300 kg) and changes in the airframe and aircraft systems;
- Tu-104V - a number of Tu-104A airplanes converted by the CAF for 100-105 seats;
- Tu-104D-85 - Tu-104A converted for 85 seats;
- Tu-104V-115 - Tu-104B converted for 115 seats;
- Tu-104A-TS and Tu-104BTS – conversion of production airplanes in medevac version (in-the-field conversion has been provided by the design of production planes);
- Tu-104AK - flying laboratory for training astronauts in short-term zero-gravity state;
- Tu-104Sh - conversion of one production Tu-104 in navigator training aircraft for training crews of Tu-16K-10 rocket carriers;
- Tu-104LL - several production Tu-104 airplanes converted for adjustment of radio equipment of Tu-128, Tu-22M and others;
- Tu-104 "relay aircraft" - was used during tests of Tu-144;
- Tu-104 2NK-8 - conversion of Tu-104 fleet (simultaneously with Tu-16) for NK-8 engines - the project was considered in the 60s;
- Tu-104D 3NK-8 - one of the first projects of the Bureau on Tu-154, which had Tu-104-based design, adapted to the new power plant;
-  aircraft "110" (Tu-110) - four-engine modification of Tu-104 intended for export. Several airplanes have been built in Kazan, but the program was terminated due to lack of contracts, and the airplanes have been used as various flying laboratories for many years;
-  aircraft "107" (Tu-107) - military transport version of Tu-104, created for the Air Force, which went through the factory and state tests but was not approved for production due to incomplete satisfaction of the Air Force’s requirements;
- aircraft "118" - project of Tu-104 with four turbofan engines.
In the period from 1957 to 1960 various versions of Tu-104 have established 26 world records of speed and carrying capacity, more than any other passenger aircraft of this class in the world. Records were established by the crews of test-pilots Y.T. Alasheev and V.F. Kovalev.

 

 

Tu-104 was in mass operation until the end of the 70s. In late 1979 Tu-104 finished its operation en the air routes of Aeroflot. But for some time, Tu-104s were used in various Soviet military organizations. Tu-104 performed its last flight on November 11, 1986 when one of the remained aircraft which was in flyable status was flying to its last parking in the CAF Museum of Ulyanovsk. Together with IL-18 - the other domestic passenger jet of the first generation, Tu-104 became for a long time the main Aeroflot passenger plane. For example, in 1960, Tu-104 performed one third of passenger air transportations in the USSR. In total, within 23 years of operation the fleet of Tu-104 has carried about 100 million passengers and spent in the air 2 million flight hours, performing 600,000 flights.  
Tu-104 has made a revolution in the Soviet civil air fleet, preparing it for operation of jet passenger airplanes of the second and the third generations.

The basic characteristics of serial aircraft Tu-104B with turbojet RD-3M-500 engines with a maximum take-off thrust of 9,500 kgf

airplane length, m 40.06
wing span, m 34.54
height, m 11.9
wing area, m2   183.5
takeoff weight, kg 78,100
payload, kg 12,000
cruising speed, km/h 750-800
operating altitude, m 10,000 - 12,000
range with a payload of 12,000 kg, km   2,120
range with full fuel load and payload of 8,150 kg, km 2,750;
number of passengers, persons 100
crew, persons 4-5