Tu-121

In 1957 OKB-156 headed by Andrei Nikolaevich Tupolev began to develop a fundamentally new subject. In the traditional area of the OKB - aircraft construction, the situation seemed quite favorable. The output of the intercontinental Tu-95 was increased, at three plants there was a Tu-16 series, in the pilot production there was the first prototype of the supersonic "plane 105". The tests of the passenger Tu-104 were completed, the "Tu-95 conversion" was being worked out.

At the same time, Tupolev was worried by NS Khrushchev's growing interest in the development of missile weapons. By the beginning of 1957 the preparation for the flight tests of the first Soviet R-7 ICBM was being completed, the first strategic missile with the nuclear charge P-5M was flight tested. Against ballistic missiles proved to be ineffective by all means, both existing in those years, and advanced air defense (air defense). On the contrary, for the conventional means of long-range aviation, the deployed air defense system of the North American continent NORAD could become an almost insurmountable barrier.

The Tu-121 was a Mach 3 intermediate range cruise missile that was tested in 1958-1960 before cancellation. The TU-121 was a strategic unmanned aircraft-missile of surface - to - surface' class designed for long flight at speed of 2700 km/h at altitude up to 25000 m which structure and equipment were affected by heat barrier. The first start was on the 26 August 1959. Two more successful test flights were made. Produced in small series to be used when trying out of TU-123 Hawk unmanned reconnaissance aircraft representing a further development of 121.

In 1956, a new subdivision of OKB-156 by A. N. Tupolev ("Department K") was launched to create a medium-range unmanned airplane "121" (product "C") with an astronertic guidance system designed to defeat strategic targets at range up to 4000 km. The resolution of the Council of Ministers of the USSR on the creation of a strategic strike system with a range of 3000 to 4000 km with an exit for tests in mid-1959 was adopted on September 23, 1957.

At the end of 1957 TUPOLEV Design Bureau appointed a group of specialists to start activities on unmanned air vehicle. The activities were headed by Alexey A.Tupolev. The work started without formal orders making no special publicity. It was not a passion with popular subject - from the very beginning the new tenor of advanced aviation was treated seriously. First of all it can be explained by increased requirements to aviation development in accordance with state-of -the-art level of that times. Certainly there was a rational attitude to application of aircraft capable to operate without pilot saving his life. Absence of the pilot in an air vehicle immediately puts much more severe requirements to such aircraft characteristics as G-force, altitude, vibration, temperature and some others.

To-day it does not matter how the DB started working on the new trend of aviation - wether it was done under Government Decree or in Andrey Tupolev initiative supported by the higher authorities. By the way, at that time the DB performed many investigations in various trends of aviation. Andrey Tupolev appealed to Commandment of Army and to Government with issues on many of these investigations. It was normal way of working at that time. In 1957-1958 Alexey A.Tupollev together with his assistant Victor Saharov elaborated a structure of new division, gathered the backbone of the collective, defined key trend of work. And the work started in full swing. The core of the team was composed of V.Blizniuk, Y.Orlov, N.Kozlov, V.Andreev, A. Davtian, A.Kochrgin, G.Cheriomuhin, A.Kaandalov, S.Svirskiy, B.Saharov, B.Stoma, V.Ryabenko, G.Polezhaev, Y.Shumilov, G.Gofbaauer, B.Grozdov, L.Lanovskiy, V.Kulinskiy. All of them were emplyees of the Design Bureau and rather young people. Said division was a part of the DB and was designated by index "K".

The first task of said new collective was building of unmanned strike aircraft of strategic purpose (TU-121, "C" aircraft). This was unusual work for the DB. It was not because of complexity of the air vehicle itself having rather high technical characteristics : booster-rocket launching at takeoff equal to 35 t, cruise flight at the speed up to 2700 km/h at the altitude of 22000 m and range of 4000 km. When work started the most unusual were the requirements to combat application of the air vehicle and operation. Complex composed of several air vehicles and aids of ground support had to be completely autonomous and capable to leave their bases independently, to operate from unprepared fields maintaining combat condition. It was necessary to solve problems of no aviation nature which were not considered in the DB previously. Management of the division had to arrange new services, to establish business links with non-aviation organizations.

Designing of the air vehicle itself also raised a number of technical questions. Such as selection and test of unusual aerodynamic layout, heat demand, especially of radio-equipment, development of autopilot system that provided both stabilization of the air vehicle and capability to fly along preprogrammable path. It was necessary to build multimode short service life turbojet engine that operates at reheat power, to design air intake that provides engine operation both under sub-sonic and supersonic conditions. There also were questions regarding fuel system functioning in view of in-flight fuel heating and some other problems. Airframe skin temperature in flight was equal to 100-120oC. Total start thrust is 160 tf at operating boosters and reheat power main turbojet engine. So there were many issues difficult from technical point of view. And the collective began to solve them.

It should be noted that Alexey A.Tupolev showed himself worth as manager of the project. He always showed high capacity for work. He worked 10-12 hours a day being in contact with specialists substantially all the time.

To launch the projectile, equipped with a short-range short-life afterburner engine KR-15-300, developed at OKB-ZOO, the starting solid-propellant accelerators PRD-52 with a thrust of 75,000-80000 kg were used. Starting engines were installed on the guide of the launcher and formed the starting unit PAT-52. During the time of 3.75-5 seconds, the starting accelerators informed the aircraft about a speed of about 165-170 km / h and brought it to a height of about 100 meters.

The astronavigation system was derived from that developed for Burya, built by NII-1 MAP under V G Chachikiyan. The missile was carried on an ST-10 mobile launch trailer, with the wings removed for transport. The astronavigation system would engage five minutes after launch. The missile would already have covered 200 to 300 km of range before reaching its cruise altitude.

Cruise engine at a resource of 15 hours provided a normal static thrust of 10 tons, and in the afterburner mode - up to 15 tons for 3 hours. The flight altitude (about 20,000 meters) was reached at a distance of 200-300 km from the launching point. The accuracy of aiming the projectile on the target was ensured by the use of an inertial guidance system, astronavigation system "Earth-AI" and autopilot AP-85. When the calculation point was reached, the "C" product was transferred to a dive at an angle of about 50 degrees.

The missile would pitch over at the target into a dive at a 55 degree angle. The thermonuclear warhead would detonate at 2 km altitude. In the event of any deviation from the planned course, an internal destruct system would destroy the missile. The Tu-121 was to have been equipped with a '205' nuclear weapon built by NII-1011, with a total mass of 3 tonnes.

In case of abnormal situations, the product "C" self-destructed. Self-liquidation was carried out with a lateral deviation from the set course or a turn, with an unscheduled decrease below 15 km. To reduce the danger and prevent serious damage during the flight over its territory, self-destruction occurred with a "passive undermining" of the product without triggering a combat charge, after passing the distance and transferring to a dive, self-liquidation was made only with the destruction of the combat charge.

A launcher weighing 21.25 tons was towed by a "launch vehicle" at a speed of up to 40 km / h on the highway or up to 20 km / h on a dirt road. "Starter car" was created on the basis of the car YAZ-2?0D, manufactured by the Yaroslavl Automobile Plant from 1951 to 1959, equipped with a hydraulic crane-manipulator. In addition to ensuring the launch of the projectile, the launcher was also used for its transportation. The vehicles were removed and attached separately to the wing console console, rudders, starting accelerators. The combat unit and control equipment were transported separately from the projectile by a special vehicle.

Tests of the prototype of the projectile were carried out on December 30, 1958 in Faustovo, later at the Polygon in Vladimirovks. Since August 26 , 1959, the tests were carried out on full-scale samples. Five prototypes were built; the first fuselage was completed in June 1958 and the first prototype was completed in late 1958 at Yauz. Launcher tests were conducted in the winter of 1958-1959 at the NIIAS test center near Moscow. The first launch with an incomplete system was conducted on 31 December 1958 (thereby fulfilling the decree schedule). In 1959 the first full prototype was delivered to Vladimirovka, followed by the first unsuccessful launch attempt on 25 August 1959. A total of four flight tests had been completed when a decree of February 1960 cancelled all further work on winged long-range missiles. A total of seven cruise stages were completed at the time the project was cancelled.

On 11 November 1959 the Commission on Military Industrial Issues (MIC) proposed to stop the development of a number of unpromising examples of jet weapons, including the "Burya", P-20, "C", as well as the Tu-95 air strike complex - carrier "C" (it was also developed in the version of the air-to-surface missile from the end of August 1958). The final decision was made by the government on February 5, 1960. The verdict was strict, but it was fair. At the end of 1959, the ballistic missile R-12, developed under the guidance of MK Yangel, with a range of up to 2,000 km, was adopted, according to the accuracy of the hits, about twice as large as the "C" .

Works on large-range unmanned strike aircraft which started in 1958 were stopped in 1960 defining a basis for activities on unmanned reconnaissance aircraft "Yastreb"-DBR-1. Said works were successfully completed in 1964. From 1965 DBR-1 complex entered serial production. The aircraft had unique characteristics for that time. It was completely autonomous for combat missions and data acquisition and processing.

However the Tu-121 was elaborated into the Tu-133 intercontinental cruise missile design, which in turn was the basis for the DRB-1 Yastreb trisonic target drone, which did reach production.