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Tupolev TU-126 Moss - Design Evolution

According to the project, the substantial changes concerned the fuselage construction and content of equipment, and also number of aircraft systems. The air crew cabin practically did not change, it became only at the work site of navigator somewhat more closely because of the auxiliary equipment. The upper deck was cellular. In the first were placed BY [BEVM], the operator's positions and the part of the blocks of the "Livna / Liana" radar. Afterwards was arranged the cloakroom, further - the second section (it remained that reserved for the auxiliary equipment). In the third section was placed working the place pointer of the remote stern cannon installation, which consisted of two guns AM-23, fire-control radar “krypton” and television sight. In the following, fourth section the places of leisure were located. In the fifth were mounted the blocks of station “Livna / Liana”. In the sixth section were placed the blocks of radio-technical system “crystal”.

In the region of the fifth section on the fuselage was established the powerful pylon, to upper part of which was fastened the revolving fairing with the antenna block RLS. On the lower deck was placed the part of the aggregates of aircraft systems and the equipment for radio-electronic opposition. Under the fuselage in the region of the fifth section was mounted the fairing about the liquid and air coolers, with the aid of which was supported the normal temperature conditions of the blocks of station “Livna / Liana”. For guaranteeing the acceptable yawing stability characteristics and aircraft handling, additional strakes were fastened.

The quantity of illuminators was considerably reduced. The selection for the installation to the aircraft of RLS “Livna / Liana” was at that time considered as the present miracle of technology. According to declared data, it made possible to detect aerial targets at the distances from 100 to 350 km (depending on their sizes) and waterborne targets, such as cruisers, at the distance to 400 km. The onboard telecode equipment had to transfer obtained information to the control centers PVO (Air Defense) and Navies, located at a distance of up to 2000 km.

In order to ensure circular scan, antenna system RLS “Livna / Liana” it was necessary to establish above the fuselage on the pylon with a height of 2.6 m and to revolve in the process of work with a velocity of 10 revolutions per minute. This conducted to the great difficulties with the creation of aircraft. Two assembly design solutions were proposed for the system of the fairing antenna: the revolving antenna inside the fixed fairing, fixed on the pylon, and the antenna, which revolves together with the fairing on the same pylon. The later idea was advanced by A.I. Putilov. Relying on the results of detailed study, he proved that the second version was lighter and simpler in design sense. at first Tupolev did not accept this proposal; moreover his argument was very weighty - where to take the bearing with a diameter of 1200 mm? Only after a sufficiently stormy exchange of opinions did the leader of the OKB became an active supporter of this idea, and personally, using his enormous influence, he "opened” the government to the solution about the production of super-bearing for Tu-126. Thus appeared the first in the world a DRLO aircraft with a revolving mushroom-shaped RLS fairing, which became an authentic technical innovation, borrowed later by the Americans.

In the process of design special attention was paid to convenient access to the aggregates of complex. In the fairing and the pylon there were special hatchways for the inspection of the RLS antenna system and performing work on it. The dimensions of fairing (diameter - 11 m, height - 2 m) made it possible for this to be done without the special complications. In contrast to the Tu-114, the Tu-126 provided for the possibility of the crew abandoning the aircraft in air through the special emergency bottom flap of the first section, and also through the niche of leading gear in the released position.

In the course of further study of project the composition and the arrangement of equipment on Tu-126 were somewhat changed. First of all, the stern gun installation was abandoned, as ineffective for this aircraft type. For expanding the possibilities of the RLS operating at a range of up to 600 km, the designers changed the arrangement of the radio-technical crew, into composition of which, besides operators RLS, they entered the chief of complex, the operators of systems [RTR] and telecode transmission of data, technician the mechanics of complex for the operational repair work in air. Above the first section they established the fairing about the heads of astros-sextant, provided number of the measures of biological protection of crew from the powerful emission of the “Livna / Liana” radar station.

After a detailed determination, the layout of the Tu-126 was refined, as was its flight performances. According to preliminary design, the maximum speed of flight was 825 km/h, cruising - 650-700 km/h, service range with the refueling - 11000 km, the time on station at range of 2000 km was 3 hours. The division of S.M. Jager together with the servicemen, approached the detailed study of questions of the combat employment of the DRLO complex under the conditions which were established at the beginning of the 60's. By that time the flight speed of the aircraft of the strategic, tactical and carrier-based aviation of potential enemy had sharply grown, which left Soviet PVO (Air Defense) too little time for bringing their forces to alert.

It was established that the introduction into the system of the DRLO complex with the stated characteristics made it possible to carry out interception of bombers flying at a rate of 900 km/h (bombers B-52, B-47, Vulcan, Valiant and Victor) some 1000 km from the coast line. For this was proposed the plan of intergrating the Tu-126 with the Tu-128 long-range interception complex, for which a group controller was included in the composition of crew. It also proved that the flight speed Tu-126 made it possible in a short time to make a guaranteed detection of air and marine enemy in any necessary direction, where the development of ground RLS was not at all possible, and in the sea regions, where to develop the shipboard means of long-range detection at the given moment is difficult under the weather conditions.

The Tu-126 had to possess high combat stability for RLS combat means. It could not be destroyed by cruise or ballistic missiles with passive homing guidance systems, intended for dealing with the working stationary locators. It was difficult to destroy by air-to-air missiles or “surface- air”, as it revealed the carriers of these rockets and their working guidance radar long before they reached the launch range. Furthermore, the mode of operation of the Tu-126 onboard radio-technical complex was designed for the disruption of tracking by passive air defense weapons of the enemy - active emission the “Livna / Liana” RLS alternated with the periods of silence, when they worked on the method only of means [RTR]. It was considered that Tu-126 it can successfully carry out tasks even with respect to the reconnaissance of carrier-based striking forces, since sufficiently high flight velocity gave to it the possibility to leave from under the impact of carrier-based fighters.

Thus almost two years of scrupulous study was spent on all questions prior to the start of building the first Tu-126 experimental aircraft. On May 30, 1960 the decision of Council of Ministers CCCP of #567-230 (the second on the complex Tu-126), and on June 10 - order [GKAT] of #217, in which as the carrier aircraft of complex finally was determined the modification Tu-114, and as onboard RLS - station “Livna / Liana”. Concrete developers and delivery times for indicator tubes with the increased resolution were established by document, along with the new systems of communications, equipment of the coding of data, national recognition and so forth. The practical coordination of all these questions by OKB-156 required work on the installation on the Tu-126 of equipment for the designation to submarines, to determine the place of conducting joint testing of complex and to ensure in IV block of 1961 its presentation to the joint flight tests.

Finally the “tactical face” of the Tu-126 was determined in the very end of 1960 as a result of the work of model commission, which sat from December 7 to 12 under the chairmanship of the deputy of the commander of PVO (Air Defense) P.Ka. Podolskiy. After this, practically all direct work on alteration Tu-114 in Tu-126 was by the Kuybyshev branch of OKB-156. In a short time this association together with basic KB prepared entire necessary design documentation and transmitted it to the plant #18, and then it actively participated in the works on building the aircraft.

Page last modified: 13-09-2021 17:22:02 Zulu