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ANT-20 (Maxim Gorky)

ANT-20 (Maxim Gorky)
Agitation, passenger multi-seat aircraft, batch produced. In the 30s - 40s, it was the largest land airplane.

Designing the largest of the land airplanes that flew in the 30's - 40's, became a logical development of the work on further increasing of weight-size parameters of heavy and extra-heavy aircraft, while remaining the initial layout and design schemes, selected for ANT-4 and further developed in ANT-6 and ANT-16, generally untouched. Initially in 1931, under the code "ANT-20", the Design Bureau was developing the four-engine passenger plane, which was a further development of ANT-16 in the direction of increasing dimensions and weight. Six M-34 engines were changed to four more powerful M-35 geared engines. The preliminary design of that aircraft was prepared and submitted to the customer, however, in autumn of 1932 the work was suspended and the Design Bureau received an urgent task that completely changed the fate of the original project.

The new aircraft’s design was based on ANT-16 (TB-4) project, but unlike it, ANT-20 was to carry 1,500 more pounds of payload and to be operated from a relatively small airfields – maximum take-off run was to be 300-400 m only (instead of 800 m for TB-4). In this regard, a new wing was designed, with enlarged area and aspect ratio, than the wing of TB-4. The power plant used eight modernized M-34FRI engines with a total power of 7200 hp (six engines were installed in the wing leading edges, and two others - in tandem installation above the fuselage). Special attention during creation of ANT-20 was paid to the design of various aircraft systems and equipment. ANT-20 was the first heavy aircraft that had rigid push-rod control system, trimmable stabilizer with fly-by-wire control system, electric servo actuators in the control system and power plant. Flight and navigation equipment of the aircraft provided its operation during day and night, including night landing on unprepared terrain. For the first time in the history of soviet aviation an autopilot was included in this equipment. Centralized electric power supply station of the aircraft generated direct and alternating current (three-phase AC system of 127 V, 50 Hz was used for the first time on the domestic plane) and supplied the payload of the agitation airplane (cinema and radio broadcast station, printing, headlights, etc.).

"MG" airplane was built in June, 1934. On June 17, 1934 the aircraft performed its first flight, piloted by M.M. Gromov. The pilot noted the simplicity and manoeuvring ability of a huge airplane. The second flight was performed two days later. "MG", escorted by two I-4 fighters, flew over Red Square, welcoming crew and passengers of "Chelyuskin" steam-ship who had returned from ice captivity. In the same 1934, M.M.Gromov and N.S.Zhurov established two world records on this plane by lifting a weight of 10,000 kg and 15,000 kg to a height of 5,000 m. In August, ANT-20 "MG" was transferred to agitation squadron n.a. M. Gorky, becoming its flagship, replacing ANT-14. Until May next year, the aircraft was successfully operated for its main agitation purpose. On 18 May, 1935 "MG" was destroyed in the crash: I-5 fighter (operated by test-pilot N.P. Blagin), escorting "MG", crashed into the wing of the plane.

In May, 1935 Council of People's Commissars of the USSR stated to build three aircraft of the same type and size instead of the crashed "MG" - "Vladimir Lenin", "Joseph Stalin", and "Maxim Gorky". A started fund raising gathered in a short time the amount of 68,113,267 rubles and 14,242 rubles in foreign currency. This allowed the Council of People's Commissars to add to the list of personalized airplanes 13 more airplanes of the same class. Urgent work started at the Design Bureau on producing drawings for the batch of airplanes, which were to be constructed at the Kazan plant №124, which building was almost finished at that time.

In the Design Bureau, production aircraft got ANT-20bis designation. The main difference of ANT-20bis was its power plant and the layout of the fuselage. New more powerful M-34FRNV engines eliminated the tandem device. The fuselage was converted for accommodating 64 passengers. Responsibility for the program of building ANT-20bis production airplanes was assigned to B.A.Saukke. The first production aircraft, designated PS-124 (passenger airplane produced at the factory №124) was put on the airfield in spring of 1939. On May 15, 1939 the plane performed its first flight, piloted by test-pilot E.I. Shvarts and his crew. Then, PS-124 has flown to Moscow, where it successfully passed state tests and was transferred to Aeroflot. The airplane performed regular flights between Moscow and Mineralnye Vody till December, 1940. Then, until November, 1941 the aircraft was in a special purpose squadron of Moscow airport. Since November, 1941 the plane converted for AM-35 engines and transferred to Uzbekistan CAF department, carried cargo and passengers on the Central Asia routes. On December 14, 1942 the aircraft crashed 90 km away from Tashkent due to violations of flight operations rules by the crew.

Apart from the agitation and passenger aircraft the Design Bureau was working on the military version of the plane. In November, 1933 the Design Bureau and the Air Force State Scientific Research Institute were discussing the possibility of using "MG" as troop carrier and bomber. As a result of the negotiations, it was decided to work out a version of the aircraft with the machine-gun/cannon defense and bombing weapons, designed for using bombs with the caliber up to 2,000 kg. The project was never executed.

The planned line of ANT-20bis was stopped, as well as works on military versions of ANT-20, because of the following: as a passenger plane for the CAF, regarding the existed passenger traffic in the USSR, it was simply not needed, and as a heavy bomber and paratroop transport aircraft for Airborne Troops with large load capacity flying at relatively low speeds and altitudes, like its prototype - ANT-16 (TB-4), it became from the second half of the 30s, a relatively easy target for air defense and front-line fighter aviation of potential enemies.
During the development of ANT-20, ANT-20bis and their experimental bomber prototype - TB-4, complex problems of the time in the field of aerodynamics, structural mechanics and strength of the structure of such large airplanes, as well as problems of creation modern avionics and mastering mass production of these aircraft were solved.

Creation of ANT-16 (TB-4) and ANT-20 ("MG"), which, by their geometric dimensions and flight weight were significantly superior to domestic and foreign heavy aircraft of the time, was an outstanding success throughout the Soviet aircraft industry and above all, the success of the team led by Tupolev.

Basic performance of ANT-20 (ANT-20bis):
• aircraft length, m - 33.0 (34.1)
• wing span, m - 63.0 (63.0)
• aircraft height, m - 11.25 (10.85)
• wing area, m2 - 486 (486)
• normal takeoff weight, kg – 42,000 (44,000)
• maximum speed near ground, km/h  - 260
• maximum speed at an altitude of 3,500 m, km/h - (275)
• practical ceiling, m – 7,500 (5,500)
• maximum range, m – 1,000 (1,000)
• number of passengers, people - 60 (64)
• crew, people - 20 (7) (with staff)