Improving the defensive armament of SB

Updated on March 13, 2019

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In 1936, SB 2-M-100 were already in production and had their combat debut in the Spanish civil war.

Some feedbacks were already available, including criticism about the poor ergonomicity of the rear defensive positions and the difficulty for the crew to intercommunicate.

In late 1936/early 1937 some attempts were made to resolve some of these problems.

 

SB 2 M-100 c/n 2255 with long glazing and turrets (early 1937)

 

 

Plane c/n 2255 was modified with a prolonged front canopy to allow the navigator to protrude and face the pilot to improve their communication; projects were made to delete the upper part of the fuselage under the canopy to make communication better.

 

A rotating turret, similar to what became the MV-3 turret, was used to increase the field of fire and the comfort of the gunner; it was a big progress over the usual TUR-3 turret, that had given bad results in the Spanish civil war.

The image shots that the landing gear bays were closed and the skis weres unretractable.

The black thing under the engine is the open cooler outlet.

 

 

The ventral gun position was improved with an opaque pod covering the machine gun on a new downwards protruding support; the ShKAS machine gun was aimed via a periscope.

Both the dorsal and the ventral turrets were successful and deemed developments, while the prolonged front canopy was no longer developed, probably because it limited the pilot's forward view.

The plane looks painted in the typical matt light grey of early SB, replaced by aluminum paint AE-8 in 1938 and by glossy light grey AE-9 in late 1939; the canopy frames were unpainted metal.

 

SB 2 M-100A with MV-3 turret (spring 1937)

 

The solutions experienced on the SB 2 M-100 c/n 2255 were refined and tested again on a production SB M-100A in spring 1937.

While the prolongation of the pilot's canopy was abandoned, probably because it reduced the forward visibility of the pilot, the dorsal turret (an early form of the MV-3) was perfectioned with an aerodynamic balancer and an openable top to enlarge the field of fire.

The ventral fairing for the ShKAS was made trasparent; the mount of the weapon was now retractable. This installation was later designed MV-2.

The tests were successful, but the installation of similar turrets on SB started only in 1940.

The plane looks painted in the typical matt light grey of early SB, replaced by aluminum paint AE-8 in 1938 and by glossy light grey AE-9 in late 1939; the canopy frames were unpainted metal.

 

Sources and bibliography:

Tupolev SB of Maslov, Ikarus Aviation press;

SB the pride of the Soviet aviation, Air War n.64 and 65;

Tupolew SB, of V. Kulikov and R.Michulek, Monografie Lotnicze 83, AJ Press

OKB Tupolev of Y.Gordon, V.Rigmant, ed. Midland

Tupolev aircraft since 1922, B.Gunston, Naval Institute Press

Tupolev SB in action- of H.Stapfer, Squadron Signal publications

 

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