Series TB-1 (ANT-4) by A.N.Tupolev

56k b/w photo from 'Technica Vozdushnogo Flota' magazine (1930th!), courtesy of Sergey V. Andreev

TB-1 series production started on Summer 1929. The last aircraft was built in early 1932. It was in front line military service until 1936, when fast development of new machines made angular ANT-4 obsolete.

It was an all-metal low-wing cantilever monoplane with corrugated duralumin skin. Duralumin was also used for aircraft frame, while joints were reinforced by steel parts. Junkers company tried to sue A.N.Tupolev and TsAGI for violating patent on metal wing, but failed. Except corrugated skin (common at the time all over the world), wing of ANT-4 seriously differed from wings of Junkers machines, it was more technological.

16k b/w photo of TB-1 fuselage frame from 'Technica Vozdushnogo Flota' magazine (1930th!), courtesy of Sergey V. Andreev

During production some construction elements were deleted (fifth wing spar, duralumin support strips under the skin) as unnecessary. Indeed, ANT-4 proved to be very reliable aircraft. During years of service as a bomber and civil transport (after retirement), no crashes due to structural failure vere registered.

Experiments with additional fuel tanks resulted in increase of tactical radius to 800km. Non-stop flight Moscow-Voronezh-Moscow was performed in 1928. Takeoff weight reached 8790kg, with 3850kg of bombs and fuel. Some of series TB-1 were equipped with extra fuel tanks following those trials (June 1933).

In October 1933 engineer V.I.Dudakov suggested to use solid rockets to accelerate TB-1 on takeoff. Pilot N.P.Blagin tried TB-1 with six rockets, arranged under and above the wing, near the roots of outer panels. Total weight of rockets was 469kg, and results were just great. Takeoff acceleration was cut down to few seconds.

Version of the TB-1 with strengthened undercarriage was used to carry parasite fighters in the 'Zveno' experiments by V.S.Vakhmistrov. Takeoff weight was up tp 12,000kg.

GDL carried out experiments by arming the aircraft with RS-132 or RS-245 (245mm unguided rocket) in 1932.

In 1933- 1935 TB-1 was used in air refueling experiments (military engineer A.K.Zapanovannij, pilot I.Belozerov). Fuel was pumped in flight from R-5 to TB-1, from TB-1 to I-15, I-16 and other TB-1. P.I.Grokhovskij used TB-1 to test his parachute systems for heavy cargo containers.

In 1935 and 1939 different systems of remotely-controlled TB-1 were tried.

For winter use special skis were a necessity. The first TB-1 was tried on all-metal Junkers skis, but those vere too heavy and weak for larger machine. Five domestic designs were tried, and all-wood design was chosen (pair weight 230kg). About 200 pairs were built.

On March 5, 1934 pilot A.V.Liapidevskij picked up first group of crashed icebreaker 'Cheluskin' survivors.

Predecessors	Modifications
TB-1 ANT-4 Dubler-bis	Strana Sovetov	TB-1P	ANT-7 R-6
	ANT-6 TB-3	Zveno	G-1