he ShB (BB-2) attack bomber first took to the air on May 25, 1940. Its design began in 1938, when even military specialists did not yet have a clear idea of ​​the "range of combat duties" of vehicles for direct support of ground forces on the battlefield. Therefore, the designers sought to provide the SB with such flight and technical parameters that would make it possible to use it for the destruction of manpower and equipment on the battlefield and for strikes against enemy communications and military facilities in its immediate rear.

To save duralumin, the aircraft was built with the maximum possible use of wood. The fuselage and keel were made entirely of wood. In the cantilever parts of the wing - of a mixed design, metal was used only in the spars, in the second rib and in the tip. The wing center section also had a mixed design.

The BB-2 aircraft was distinguished by the kinematics of cleaning and releasing the main landing gear, which retracted back into the center section of the wing with a 90 ° turn of the wheels. Subsequently, a similar scheme was used on the Su-1, Su-6 and Il-10 aircraft.

To increase the combat survivability of the attack aircraft, the armor of the main elements and crew members, the protection of gas tanks were used. The prototype of the attack bomber was armed with six rapid-fire 7.62 mm ShKAS machine guns. Of these, four were installed in the wing consoles, one in the turret and one in the lower hatch machine gun mount. The turret machine gun in flight to the target was covered with a special casing to improve aerodynamics. With a normal take-off weight of 4500 kg, up to 600 kg of bombs of various calibers were suspended on cassette holders in the fuselage compartment.

According to the calculations of the designers, the SB was supposed to develop a speed at the ground up to 350 km / h, a flight range of about 800 km, a ceiling of up to 8 thousand m. Flight tests, in general, confirmed these data. The aircraft showed good stability and controllability. However, as the very first major operations of the Second World War showed, it is still inexpedient to combine the qualities of an attack aircraft and a bomber in one aircraft. An attack aircraft needs stronger armor, larger caliber small arms, lower altitude, but higher ground speed. Taking into account these requirements dictated by life, the designers began to develop the Su-6 - an attack aircraft for the new powerful M-71 air-cooled engine. In the new aircraft, which also did not go into series, they used the developments used in the experienced ShB.

Photo	Description
	Drawing (BB-2)
	ShB on tests

• Attack aircrafts of the Red Army / Vladimir Perov, Oleg Rastrenin. /
• ShB / Wings of the Motherland. N. Gordyukov, E. Pavlov, I. Sultanov. /
• Su-2 close-range bomber / Dmitry Khazanov, Nikolay Gordyukov. /
• History of aircraft designs in the USSR, 1938-1950. /V.B. Shavrov /